52
MIXED PLASTIC RECYCLING PLANT Reck ‘em Recyclers Nunzio Carducci, Anders Hoglund, Maxon Lube, Damiana Murdock May 8 th , 2020 CHE 4080
MIXED PLASTIC RECYCLING
PLANT Reck ‘em Recyclers
Nunzio Carducci, Anders Hoglund, Maxon Lube, Damiana Murdock
May 8th, 2020
CHE 4080
1
Table of Contents I. Executive Summary ..................................................................................................................... 3
II. Scope of work............................................................................................................................. 4
III. Introduction ............................................................................................................................... 5
IV. Description of Base Case .......................................................................................................... 9
V. Design alternatives ................................................................................................................... 16
VI. Permitting and Environmental Concerns ................................................................................ 18
VII. Safety and Risk Analysis ....................................................................................................... 19
VIII. Project Economics................................................................................................................ 20
IX. Global Impacts ........................................................................................................................ 28
X. Conclusions & Recommendations ........................................................................................... 29
XI. Future work ............................................................................................................................. 29
XII. Acknowledgements ............................................................................................................... 29
XIII. References ............................................................................................................................ 30
XIV. Appendices........................................................................................................................... 33
Appendix A: Plastic Details ...................................................................................................... 33
Appendix B: Process Notes ....................................................................................................... 36
Appendix C: Methanolysis Mass Balances ............................................................................... 41
Appendix D: Detailed Pyrolysis Emissions .............................................................................. 41
Appendix E: Total Cost Analysis Excel Spreadsheet ............................................................... 42
Appendix F: Aspen Plus Files ................................................................................................... 42
Appendix G: Complete HAZOP Analysis ................................................................................ 42
Appendix H: SDS files .............................................................................................................. 51
Appendix I: Equipment Sizing .................................................................................................. 51
Appendix J: Environmental Impact Calculations...................................................................... 51
Table of Tables
Table 1: Plastic percentage in feed ............................................................................................................ 9
Table 2: Composition of pyrolysis fuel .................................................................................................... 12
Table 3: Pyrolysis reactor and condensers conditions and duty ........................................................... 13
Table 4: Pyrolysis mass balance .............................................................................................................. 13
Table 5: Methanolysis Overall Mass Balance ......................................................................................... 16
Table 6: Utility Requirements for Methanolysis Unit Operations ....................................................... 16
Table 7: Pyrolysis Reactor Emissions ..................................................................................................... 18
2
Table 8: Main equipment quantity, pricing, and total cost ................................................................... 20
Table 9: Equipment description and location ........................................................................................ 21
Table 10: Capital investment estimation based on delivered-equipment cost ..................................... 22
Table 11: Annual operating costs assuming plant runs at 100% capacity .......................................... 23
Table 12: Total revenue for major products and byproducts ............................................................... 24
Table 13: Cash flow sheet, years 0 to 10. ................................................................................................ 25
Table 14: Cash flow sheet, years 11 to 21 ............................................................................................... 25
Table 15: Cash flow sheet summary ........................................................................................................ 26
Table 16: Detailed pyrolysis emissions .................................................................................................... 41
Table of Figures
Figure 1: Overall process flowsheet showing four major stages of the recycling process. ............ 9
Figure 2: Pyrolysis process flowsheet........................................................................................... 11
Figure 3: Generic schematic of an FCC reactor (“U.S. Energy Information Administration - EIA
- Independent Statistics and Analysis”) ........................................................................................ 12
Figure 4: Aspen Plus pyrolysis simulation ................................................................................... 13
Figure 5: Transesterification of PET monomer with methanol .................................................... 14
Figure 6: Methanolysis Process Flow Diagram ............................................................................ 15
Figure 7: Sensitivity plot analyzing the revenue effect on the NPV20. ........................................ 27
Figure 8: Sensitivity plot analyzing the operating cost effect on the NPV20. .............................. 27
Figure 9: Sensitivity plot analyzing the FCI effect on NPV20. .................................................... 28
3
I. Executive Summary Mismanaged plastic waste is a serious problem, and the United States is responsible for 13% of
the annual global plastic waste production. Less than 10% of plastic waste in the United States is
recycled, and traditional mechanical recycling methods can only be used six times before the
plastic is no longer usable. Chemical recycling technologies can help solve these issues. The goal
of the following project is to design a plant that can process all seven plastic types using
chemical recycling and be economically feasible.
While this plant cannot recycle all seven consumer plastic types, it is able to accept and sort a
mixed input stream of those plastics with the objective of promoting a more circular plastic
cycle. Supercritical methanolysis will be used to recycle polyethylene terephthalate (PET) into
the virgin monomers, dimethyl terephthalate (DMT) and ethylene glycol (EG), and pyrolysis will
recycle polyethylene (PE), polypropylene (PP), polystyrene (PS), and other plastics into fuel oils.
Polyvinyl chloride (PVC) will be sorted and sold to prevent the release of chlorinated
compounds through pyrolysis.
The expected processing rate is 18,500 tons of mixed plastics and an additional 16,415 tons of
pre-sorted PET per year. Pyrolysis will process 36.6 tons per day of mixed PE, PP, PS, and other
plastics using two fluid catalytic cracking reactors with a processing capacity of 20 tons per day
each. Condensers and filtration will yield pyrolysis oil that is composed of 35% motor gasoline,
45% diesel, and 20% No. 6 fuel oil (used in industrial boilers). Byproducts such as syn gas and
light fraction residuals will be combusted to help heat the reactors, whereas carbon black will be
sold separately. According to RTI International, the emissions produced from the reactor are
insignificant requiring no emissions control system (2012). Methanolysis will process the 3.3
daily tons of PET from the sorting line and 49 tons of outsourced PET that has already been
presorted. Daily DMT production is expected at 52.7 tons at 99% purity. Daily ethylene glycol
output is expected to be 16.6 tons. These numbers are estimated based on an input of 52 tons of
PET and 312 tons of methanol.
Economic analysis assumed a 21% tax rate and 20-year lifespan with a MACRS5 depreciation
schedule. MARR was set at 20% since the recycling market is well-established, but this plant
combines new, medium-risk sorting techniques and chemical recycling processes. Equipment for
methanolysis and pyrolysis were based on data from Peters et al. Delivered equipment cost is
expected to be $7.1 million using a delivery rate of 10% of the purchased equipment cost. Fixed
capital investment totaled $28.2 million, and the total capital investment was $41.7 million.
Operational costs were found to be $16.7 million, and methanolysis electricity costs alone
contribute nearly $7 million to that figure. Annual revenue was estimated to be $28.9 million. A
cash flow analysis resulted in a payback period of 9 years, an IRR of 10%, and net present value
(NPV) of –$35.1 million at a 20% interest rate. NPV0 was calculated to be +$131.7 million.
Since the IRR does not exceed the MARR of 20%, this project cannot be recommended on an
economic basis. However, considerations should be made when viewing the plant from a
sustainability standpoint. An important note is that a gate or tipping fee was not considered in the
cash flow analysis. Preliminary analysis of additional revenue from a gate fee and/or government
subsidy show an additional $9.09 million per year ($491.37/ton of mixed plastic waste) is needed
4
to achieve an NPV of 0 at 20% interest. A gate fee of $70/ton, which is comparable to the
landfilling fee in the New York area, would result in an IRR of 12% and NPV20 of –$30.1
million.
The price of electricity presents considerable economic risk because of how much is used,
mainly in the methanolysis process. Electricity accounts for nearly half of the annual $15.8
million in variable production costs. Fluctuations of even $0.01/kWh can change the annual cost
by approximately $1 million. The sale price of DMT also poses significant economic risk if the
price were to drop. About $17.7 million of the $28.9 million in annual revenue comes from DMT
alone. Market fluctuation in the selling price can greatly affect the overall revenue.
To conclude, the project is not economically viable with an IRR of 10%. Government subsidies
and a gate fee should be considered to improve the IRR, and a competitive gate fee of $70/ton
raises the IRR to 12%, based on preliminary results. To meet a target IRR of 20%, an additional
$9.09 million must be raised per year. Further studies should be made on the impact that utilities
and market values have on the project economics due to electricity expenditures and the sale
price of DMT being critical components to the profitability of the project. Further research
should be conducted on how to effectively separate out dyes from the methanolysis products and
determine if the additional expenditures are outweighed by the marginal increase in revenue by
selling cleaner DMT and EG. CreaSolv looks to be a promising route if enough PET can be
sourced to recycle and offset the additional capital costs. Expansion of the methanolysis process
should also be considered as it can be very profitable if more PET can be processed. (Nunzio)
II. Scope of work This mixed plastic recycling plant is designed to process all seven plastic types to reduce plastic
waste generation and create valuable products and byproducts. It is crucial to increase the
percentage of waste that is recycled, plastics especially, to keep the environment healthy.
Mechanical and chemical recycling techniques will be used to process an estimated 18,500 tons
of mixed, uncleaned plastic waste per year from New York and the surrounding area. (Wimsatt,
2016). An additional 16,415 tons of pre-sorted PET will be outsourced to improve the
profitability of the methanolysis process (Genta, 2003). The plastics will go through a
preparation stage which consists of washing, drying, sorting, and shredding before the PET
plastics undergo methanolysis to create dimethyl terephthalate (DMT) and ethylene glycol (EG).
The EG and DMT then can be sold to remake PET. The PP, PE, PS, and other plastics will be
sent to a pyrolysis process to make fuel oils consisting mainly of fuel type No. 2, No. 6, and
motor gasoline while the PVC plastics will be removed, granulated, and sold separately. The fuel
oils will be sold to a refinery to be blended into commercial use concentrations. The waste
streams generated from the plant will all be non-hazardous material which can be landfilled.
(Maxon)
Constraints to the plant design include how much plastic can be sourced. Approximately 18,500
tons of plastic is produced annually by the area surrounding the plant location in New York
(Wimsatt, 2016). Mixed plastic waste streams are variable, and the amount of PET can be as low
as 6% (RTI International, 2012) to as high as 10% (Bodzay and Banhegyi, 2017). This report
assumes a PET fraction of 6%. However, methanolysis requires significantly more PET.
Approximately 20,000 tons of PET must be processed annually to make the methanolysis
5
process economically feasible according to Genta (2003). Other studies have found the minimum
profitable amount to be 15,000 tons annually (Aguado, 2007). To maintain overall profitability
of the plant, 20,000 tons of PET will be processed annually with about 16,415 tons being pre-
sorted PET waste that is purchased. This plant is unfortunately unable to process every type of
plastic. PVC cannot be processed in either reactor, and it can destroy the pyrolysis catalyst if
pyrolyzed. Due to this and the toxic nature of combusted PVC, an IR sorter will be used to sort
out PVC.
Technical constraints to the project include the 86.7% efficiency of the pyrolysis reactors (RTI
International, 2012). The overall plant processing capacity is limited by the infrared (IR) sorting
machines to an average of five tons per hour and a maximum of eight tons per hour. This
processing limit is dependent on the width of the machines purchased as it can vary from 2-10
feet (4R Sustainability, 2011). The preparation process equipment also presents capacity
constraints, but their capacities are not lower than the IR sorters.
The project has several safety constraints due to the use of hazardous equipment and materials.
The moving parts in the shredders and granulator present operational hazards. The methanolysis
process uses flammable methanol at supercritical conditions (300oC and 1176 psi). The fuel oils
produced by the pyrolysis reactor, which operates at 350oC, must be managed appropriately, and
there should be minimal amounts stored onsite due to the flammability risk. The pyrolysis
reactor also emits air pollutants such as CO2, NOx, and particulate matter. Current processing
rates do not necessitate a control system for these emissions. PVC in the mixed plastic stream
poses a risk if it is accidentally pyrolyzed. Combustion of PVC would lead to a release of toxic
chlorine gas. (Nunzio)
III. Introduction According to the EPA (“National Overview,” 2019), the United States generates approximately
35 million tons of plastic annually, and the World Bank (“What a Waste 2.0”) estimates that 265
million tons of plastic waste are produced globally. Therefore, the United States alone generates
13% of the total global plastic waste every year. The U.S. consistently ranks in the top 20
countries for having the most mismanaged plastic waste and is also the only high-income country
to be on the list (Jambeck, 2015). This is a problem because the United States has the
technologies and economic capabilities to develop solutions.
Mismanaged plastic waste is an issue for the environment, especially marine life. Plastic that
ends up in oceanic garbage patches can be fragmented into small particles that can be ingested by
marine life (Jambeck, 2015). The best solution to this issue is to reduce total plastic inputs to the
environment.
Currently, the U.S manages plastic in 3 ways: landfilling, combustion for energy recovery, and
recycling. Approximately 76% is landfilled, 15% is combusted for energy, and 9% is recycled
(“National Overview,” 2019). Part of the reason the amount of recycling is insignificant is the
lack of a circular recycling process. Plastic is traditionally recycled by washing and melting the
material, granulating it, and then reforming it into a new product. However, this method
produces plastics that cannot be reused for their original purpose. One reason is that the washing
process does not remove enough contaminants for melted plastics to be considered safe for reuse
in food products by FDA guidelines. Another reason is the melting process degrades the physical
integrity of the plastic—it loses quality and strength with each melting process. Thus,
6
traditionally recycled plastic cannot be reused in the same product it was made from and is often
downcycled into other products. Additionally, there is a critical amount of times plastic can be
downcycled before it is no longer useable. PET, for example, can only be downcycled 6 times
before it can no longer be reused. The issues associated with mechanical recycling technologies
can likely be remedied through chemical recycling technologies. (Damiana)
Several approaches to plastic recycling are in use, but they all have one thing in common:
mechanical sorting. Mechanical sorting is the use of the various physical and chemical properties
of each plastic type to separate them into pure streams. The most common approach, known as
flotation or float-sink separation takes advantage of the density differences among various plastic
types. The plastics are placed in a separation fluid and will float or sink depending on their
density in relation to the liquid. Water is typically used as the fluid to separate PE and PP from
other plastic types because both plastics have densities that are less than 1 g/cm3. A limitation of
this method is that PE and PP are the only two types that can be reliably sorted. Denser fluids
such as dichloromethane (density = 1.36 g/cm3) have also been used in practice. However, water
is considerably cheaper to use, especially since large quantities of the separation fluid are
needed. The denser fluid does not necessarily improve the separation of other plastic types
because most plastics have an overlapping range of densities and each stream would still be
contaminated with other plastic types (Shent, 1999). (Nunzio)
Another mechanical separation approach is tribo-electric separation, which uses static electricity
to separate the plastics. Inside a rotating drum, the plastics rub against each other and generate
static electricity. Each type of plastic has a unique signature that can be read with a sensor made
of two highly charged electrodes. After being charged, the plastics fall between the electrodes
and create a unique electric signature. This technology is advanced, but it does not appear to
have practical applications for this process design. Any additives for coloring or added strength
and flexibility will change each plastics’ unique signature. This can give a false reading, leading
to misidentification. Also, several pure plastics have similar charges which makes it difficult to
separate them. This may be a more viable option in the next ten years after the completion of
more research (Li, 2015). (Anders)
Mechanical recycling methods (washing, melting, and reforming) are commonly used today;
however, chemical recycling has gained attention because of its ability to produce valuable
products and its allowance for a more circular recycling technology. There are three main types
of chemical recycling: chemolysis, pyrolysis, and gasification.
The most well-known of these techniques is gasification, in which a wide variety of untreated
organic feedstocks are converted to syngas with an oxidation agent such as oxygen or air. The
drawbacks to this technology are its production of relatively high amounts of NOx and other
contaminants and its high reaction temperatures (ranging between 1200-1500 °C). The NOx and
other contaminants must be cleaned to meet emission requirements and to purify the product
stream that may be sent to other catalytic processes that are sensitive to such contaminants
(Ragaert et al, 2017).
The pyrolysis of waste plastics involves the thermal decomposition in the absence of oxygen or
air. During the pyrolysis reaction, the polymer materials are heated to high temperatures and
their macromolecules are broken into smaller molecules, resulting in the formation of a wide
range of hydrocarbons. Pyrolysis can be further defined by its numerous reactor types: batch,
semi-batch, or continuous flow. Batch and semi-batch reactors are generally used in laboratory
7
settings, but they become infeasible when the process is scaled up. Thus, a continuous reactor is
preferable for this plant. All three types of reactors can carry out the pyrolysis process via
catalytic or thermal cracking. Thermal cracking has historically been used due to its simplified
chemistry; however, it requires a large input of heat (Sharuddin et al, 2016). Thermal cracking
pyrolysis can be run in the range of 350-900°C, but a temperature of at least 500°C is required
for favorable yields (Almeida, 2017). Catalytic cracking has not been used previously due to the
complexity of the reaction and expensive catalysts. However, recent advancements in technology
have mitigated these drawbacks. Catalytic cracking reactors have been run in temperature ranges
of 300-400°C while maintaining favorable yields (Ragaert et al, 2017). (Maxon)
Another promising recycling method is chemolysis. Chemolysis has been of interest because it
converts plastic back into its monomers that can be repolymerized as new plastics. However, this
technology is only applicable for step polymers and is currently only used to process PET. There
are currently two chemolysis methods used industrially: methanolysis and glycolysis. While
methanolysis typically requires a large processing capacity due to the large capital requirement,
glycolysis can still be profitable for small and medium plants. Methanolysis also requires a very
pure feed of PET as the input, and glycolysis can more readily handle contaminants in the
feedstock. Methanolysis will create dimethyl terephthalate (DMT) and ethylene glycol (EG)
from PET. Two mechanisms are currently used for methanolysis, and both require high
temperatures and pressures. The first is to heat and melt the PET to reaction temperature and
then contact it with liquid methanol in the presence of a catalyst. The second is to supply
supercritical methanol to the purified PET. This second option has shown great promise by
depolymerizing the PET faster and with higher yield, and the reaction at supercritical methanol
conditions does not require the use of a catalyst (Aguado, 2007). One study has suggested that
near complete depolymerization is possible for PET in supercritical methanolysis with excess
methanol after 1 hour of reaction time. There is up to a 95% yield of DMT (the remaining 5% is
oligomers of the PET monomer). The greater the ratio of methanol to PET, the greater the
depolymerization percent and yield of DMT. (Yong, 2019). Glycolysis, on the other hand, is the
reaction of PET with excess ethylene glycol at temperatures between 180 and 240℃. This
reaction produces bis(2-hydorxyethyl) terephthalate (BHET). Zinc or lithium acetate is
commonly used as a catalyst for this depolymerization, but others have been tested in the lab as
well and may soon be used in commercial applications (Aguado, 2007). Both methanolysis and
glycolysis require separation processes to recover the desired monomers after the
transesterification reactions. (Damiana)
Current plastic recycling plants typically use a combination of mechanical sorting and chemical
recycling. However, unlike the plant designed in this approach, current chemical recycling plants
use only one type of chemical recycling. Pyrolysis plants are in operation across the United
States in Maryland, Oregon, Georgia, and New York. Each plant receives a variety of untreated,
unsorted mixed plastics that are shredded and pretreated before being sent to a pyrolysis reactor.
to create refined petroleum products. These plants receive anywhere from 3,650 to 10,000 tons
of mixed plastic a year, and the plants in Maryland, Oregon, and Georgia can process all seven
types of plastics; however, the ability to process such a wide variety of feedstock comes with
some costs. The plants are limited to using thermal cracking and lower operating temperatures
because the chlorines in PVC can create hydrochloric acid, which contaminates the catalyst and
products. To limit contamination, the reactors are run around 400 °C which results in lower
yields with a maximum of 75% recovery (RTI International, 2012). Outside of the United States,
8
China has several pyrolysis plants in are of similar sizes with the smallest being able to process 6
tons a day and the largest processing 30 tons a day. These plants vary from using batch, semi-
continuous, to continuous reactors, and each have slightly different processes to make them more
advantageous (Lin, 2018). (Maxon)
Eastman Chemical Company is currently developing a circular recycling methanolysis process
for polyester based plastics to be fully functioning within the next 3 years. (“Eastman Offers
Innovative Recycling Technology for Polyesters,” 2019). Although the company has not
disclosed process-specific information, it does plan on using methanolysis to convert recycled
PET feedstock into monomers to meet the demands of its customers. Additionally, Mitsubishi
has designed a B to B recycling process (bottle to bottle) designed to convert post-consumer PET
bottles into virgin monomers to be remade into PET bottles. The Mitsubishi process uses
supercritical methanol depolymerization, reports reaction times of 10 minutes, and monomer
yields of greater than 99.9% after the distillation process. However, the Mitsubishi process does
not stop with methanolysis. The purified DMT is sent to a hydrolysis section to be converted to
terephthalic acid (PTA). PTA and ethylene glycol are then sold as the PET resins to be
repolymerized into PET product. The company estimates that 20,000 to 40,000 tons of PET
bottles would need to be collected every year to be economically feasible (Genta, 2003).
(Damiana)
The recycling plant being designed has considered and combined some of the approaches from
above. As mentioned previously, chemical recycling must begin with a mechanical sorting
process. Density-based separation is adequate for melt-based recycling, but processes such as
float-sinks can only separate PP and PE effectively from a mixed plastics stream (Ragaert et al.,
2017). The chemical recycling processes that promote a circular plastic cycle only process
certain types of plastic. Infrared (IR) sorting is the simplest technique to accurately sort mixed
consumer plastics. Infrared spectroscopy will be used because each polymer has a specific
reflective spectrum. The unique spectra result from different vibrations in the C—H, O—H, and
N—H bonds in the polymers (Zhu et al., 2019). As a result, infrared sorters can sort any
combination of the seven consumer plastics. Current IR sorters have an accuracy of up to 99%
and can sort up to eight tons of mixed plastic per hour (4R Sustainability, 2011). (Nunzio)
Due to chemolysis creating a pure, high value product and pyrolysis being suitable for a wide
range of feedstock, a combination of the two were chosen for this plant (Ragaert et al, 2017).
Specifically, a continuous fluid catalytic cracking pyrolysis process was chosen because it has a
higher capacity than batch or semi-batch pyrolysis processes, and continuous fluid catalytic
cracking operates at a lower operating temperature than thermal cracking due to its use of a
catalyst. (Maxon)
Supercritical methanolysis was selected as the chemolysis process. This process was chosen
because methanolysis plants need to be designed to take in large feedstocks, and this emphasizes
the part of the scope to reduce total plastic waste. Supercritical methanolysis also does not
require a catalyst for transesterification because the high temperatures and pressures will damage
the catalyst. Using no catalyst simplifies the purification process. Additionally, several studies
and industrial applications have shown that PET depolymerization and DMT yields are typically
above 95% with short reaction times. Unlike the Mitsubishi process, methanolysis at this mixed
plastic recycling plant will be batch instead of continuous. The reaction will also stop with the
formation of the DMT unit, and subsequent hydrolysis will not be used. Additionally, longer
9
reaction times will be used to promote further PET depolymerization as conversion in the
Mitsubishi process is 80% yield. The mixed plastic recycling plant will allow 1 hour for reaction
time rather than 10 minutes. (Damiana)
IV. Description of Base Case As shown below in Figure 1, the mixed plastic recycling plant has four main stages: plastic
preparation, sorting, chemolysis, and pyrolysis. The plant will be able to receive and process a
stream consisting of all seven types of plastics. Plastic preparation will remove contaminants
from the feedstock. Infrared sorting will separate the plastics into three major categories: PET,
PVC, and PE, PP and PS. After sorting, the plastic will be shredded and sent to its respective
chemical process. PVC will be not be processed after sorting and will instead be granulated and
sold. PET is sent to methanolysis to be converted into DMT and EG. Pyrolysis will convert the
PP, PE, and PS plastics into fuel oils by using a fluid catalytic cracking pyrolysis reactor.
Figure 1: Overall process flowsheet showing four major stages of the recycling process.
The plant is designed to receive 18,500 tons of mixed plastic feed a year (55 tons per day). Table
1 details the amount of each type of plastic in the feedstock in tons per day (Ragaert et al, 2017).
Note that this table does not include the total amount of PET that will be processed. Additional
pre-separated PET will be fed directly into methanolysis and will be discussed in more detail in
the methanolysis description. (Damiana)
Table 1: Plastic percentage in feed
Plastic Type Feedstock (ton/day)
PET 3.3
HDPE 7.15
PVC 10.45
LDPE 13.2
PP 10.45
PS 3.3
Other 5.5
EPS and ABS 1.65
10
Plastic preparation is a vital part of plastic recycling. This process includes prewashing, friction
washing, and drying. Prewashing is necessary because post-consumer plastics are often heavily
contaminated and loaded with foreign matter. Possible contaminants include organic material,
dirt, and small pieces of trash that were not separated out from the plastics beforehand. This
process uses the Lindner pre-washer. The Lindner pre-washer can process 4.3 tons of mixed
plastics per hour, using 28.5 kW of energy/hr. Prewashing removes 55-60% of contaminants,
leaving 40-45% of contaminants that still need to be washed out (Sánchez, 2011).
The next step of plastic preparation is friction washing. This process produces a 95% pure mixed
plastic feed. Friction washers are high-speed water cleaning machines typically only used for
mixed plastics, and they require another washing process beforehand. The friction washer is a
high-velocity rotating drum with a counter-current flow of water. The countercurrent flow and
revolving drum cause the plastics to rub against each other, thus removing contaminants. The
contaminants are removed from the drum quickly due to the countercurrent flow and are sent
through a series of filters and screens before the water is recycled through the system. Even
through the energy requirements are high (55kW/hr), Polestar Machinery’s friction washer meets
all design specifications for this process. It has the same processing capacity as the prewasher, 4
tons of mixed plastics per hour. Polestar Machinery’s friction washer is one of few continuous
flow friction washers. Typically, friction washing is done as a batch process, which yields higher
percentages of pure plastic; however, the residency period is an hour in the batch process
whereas only 15 minutes with the continuous flow process. This allows an additional 4% of pure
plastic (Polestar Machinery, 2019).
The final step of plastic preparation is drying the mixed plastic stream. The unit operations
following the preparation are sensitive to moisture. Thus, it is critical that the plastic is
thoroughly dried. This process uses Rotajet Recycling’s RJ-MD-55 Dryer. This horizontal
mechanical dryer is fit with a blower (5.5 kW/hr) and heater (36 kW/hr) that are effective to
remove 99% of all water through centrifugal drying. The RJ-MD-55 Dryer has a rotating drum
that operates at 1450 rpm. The dryer is also fitted with paddles made of D2 steel that are easily
interchangeable, with the purpose of cutting down on maintenance time (Rotajet Recycling,
2019). (Anders)
After the preparation stage, the mixed feed will be fed through infrared sorters. Infrared sorters
are less common because they are more expensive than density-based separation equipment, and
current recycling techniques do not have a high specificity for the input plastic composition.
Methanolysis and pyrolysis are both very specific in their feedstock requirements, but they also
work towards the goal of a more circular plastic cycle. Methanolysis requires PET, and pyrolysis
accepts PP, PE, and PS. A series of National Recovery Technologies (NRT) SpydIR-R sorters
will be used because they have a sorting accuracy of 99% and can sort any combination of the
seven consumer plastics (4R Sustainability, 2011). The three SpydIR-R’s will sort out target
plastics into the following streams: PVC; PET; and PP, PE, and PS. Maximum throughput for
each machine is up to eight tons per hour (NRT, 2019). The choice was made to separate out
PVC because of its value as a secondary raw material, and PVC will form chlorine compounds if
it is pyrolyzed. Chlorinated compounds destroy the pyrolysis catalyst and contribute to harmful
emissions. (Nunzio)
11
After separation, each plastic stream will be shredded in its own shredder. This process uses
Shanjie Machinery’s Plastic Shredder. 90% of the shredder’s output will be smaller than 60mm.
Each shredder can operate with up to 5 tons per hour and uses 60 kW/hr of electricity (Shanjie
Machinery, 2019). The next step for the PVC stream is granulation. To sell the PVC it needs to
be in uniform, predictable sizes. The Plastic Recycling Machinery’s (PRM) dry granulator
requires 55 kW/hr and is used in this process. Granulation is a process where small flakes or
plastic are cut into smaller (10-25mm) pieces. In a rotating drum, large knives crush and cut the
shreds of plastic being feed into it. There is an adjustable sized mesh in the drum that that the
plastic will fall through once small enough. The mesh can also be adjusted to make smaller or
larger plastic granules. The mesh range includes diameters between 10 and 25 mm (Plastic
Recycling Machine, 2019). (Anders)
The PP, PS, PE, and other plastics are sent to the pyrolysis process after the sorting stage. As
shown below in Figure 2, the plastics are fed to two pyrolysis reactors which will produce
exhaust, waste, carbon black, and gaseous fuel. The fuel will consist of hydrocarbons of various
lengths that must be condensed into liquid form. After going through the first condenser and
separator set, the liquid phase consisting mainly of fuel No. 6 (industrial boiler fuel) will be
removed, leaving the remaining vapor to go through a second condenser and separator set. This
set will lower the temperature of the vapor to create liquid fuel No. 2 (also known as diesel) that
can be separated easily. The final condenser and separator set will remove the motor gasoline
from the light gas fractions and syngas which can be used to heat up the reactor. Byproducts,
such as carbon black (an energy dense solid), can be sold as a fuel source for combustion or used
like the syngas to heat up the reactors. The very small amount of non-hazardous waste produced
will be landfilled (“Waste Plastics Pyrolysis Plant,” 2018). Finally, the exhaust produced from
these reactors already meets emission standards negating the need for additional exhaust cleaning
equipment. A detailed mass balance for the exhaust can be seen in Appendix D (RTI
International, 2012).
Figure 2: Pyrolysis process flowsheet
12
The reactors are fluid catalytic cracking (FCC) reactors. These reactors are common in the oil
and gas industry and produce most of the fuel that is used today. Figure 3, shown below,
illustrates a generic schematic of an FCC reactor. The feedstock enters at the bottom where it is
sent through a pump where it reacts with the catalyst in the riser. The catalyst is removed in the
stripper and is sent to be regenerated while the fuel continues through the process. The
regenerator requires an input of combustion air and produces flue gas to be used in other parts of
the process.
Figure 3: Generic schematic of an FCC reactor (“U.S. Energy Information Administration - EIA
- Independent Statistics and Analysis”)
Specifically, the process will use two reactors that each have a capacity of 20 tons of plastic per
day, have a 92% recovery efficiency, and only take up 1000 ft2. The product fuel oil will consist
of 86.7% fuel oils, 6.8% carbon black, a small fraction of syngas, and the remaining amount is
nonhazardous waste (RTI International, 2012). Furthermore, the use of a Z2SM-5 catalyst
reduces the operating temperature of the reactor down to 350 °C, and each reactor will require
about four tons per year of this catalyst (Sharuddin et al, 2016). The reactors will produce a fuel
with an expected composition shown in Table 2 shown below (Kunwar et al).
Table 2: Composition of pyrolysis fuel
Motor gasoline Fuel No. 2 Fuel No. 6
% of total 35 45 20
While an operating temperature of 350 °C is relatively low for a pyrolysis process, it will still
require a significant amount of heat to reach this temperature. Once leaving the reactor and
entering the sequence of condensers and separators, a significant amount of heat will be released
due to lowering the temperature and the phase change occurring. To estimate the amount of heat
required and given off in the condensers, an Aspen Plus simulation was created and can be found
in Appendix F. The process flow diagram is shown in Figure 4.
13
Figure 4: Aspen Plus pyrolysis simulation
Since complex polymers like plastics cannot be modeled in Aspen+ and pyrolysis reactors are
not one of the premade available options, to model the reactor, the feed stock temperature was
increased from 25 °C while the pressure was increased from 1 atm to 4.1 atm. The following
condensers brought the temperature and pressure within ranges to maximize the amount of each
fuel type. The calculated reactor and condensers conditions and duty are shown in Table 3
below.
Table 3: Pyrolysis reactor and condensers conditions and duty
Unit Outlet Temperature °C Pressure atm Duty BTU/hr
Reactor 350 4.1 1,185,870
Cond1 225 1 – 450,190
Cond2 100 1 – 416,523
Cond3 20 1 – 73,861
This heat can be conserved and transferred to other parts of the process by using a heat
exchanger. If the heat exchanger works at 100% efficiency, a total of 245,296 BTU/hr can be
converted into the regenerator in the FCC reactor requiring a smaller amount of energy needed
from other sources such as natural gas. After leaving the reactors and being liquified in the
condensers, the fuel must be separated, allowing the motor gasoline, fuel No. 2, and fuel No. 6 to
become their own streams; however, these streams are not pure. They will need to be sent to an
oil refinery to be blended with their product streams before reaching consumer grade. The
amount of each product produced from the reactor can be found in the mass balance for the
pyrolysis process as shown in Table 4 below.
Table 4: Pyrolysis mass balance
Material Input (ton/day) Output (ton/day)
HPDE 7.15 0
LDPE 13.2 0
PP 10.45 0
14
Material Input (ton/day) Output (ton/day)
PS 3.3 0
Other 5.5 0
Motor gasoline 0 12.02
Fuel No. 2 0 15.45
Fuel No. 6 0 6.87
Carbon black 0 2.70
Waste 0 2.5
(Maxon)
The other main chemical recycling process that will be used is methanolysis. Methanolysis
involves a transesterification reaction between methanol and the polyethylene terephthalate
(PET) scraps as shown in Figure 5 below.
Figure 5: Transesterification of PET monomer with methanol
This process will utilize the supercritical methanol method discussed previously. A highly pure
feed of PET will enter the reactor. Approximately 3.3 tons per day of PET will supplied from the
mixed plastic input and separation streams. An additional 49 tons per day will be outsourced or
purchased from other mechanical sorting facilities. Figure 6 below shows the general schematic
for the methanolysis process.
Methanol at 572℉ and 1176 psi (supercritical temperature and pressure) and in 6 times weight
excess will contact the PET. The reaction will run for no longer than 1 hour to allow time for
near complete depolymerization (Yang, 2001). Five reactors are needed to account for the
volume of gaseous materials during each reaction, and the products will be combined
downstream. There are 2 methanol streams entering the reactor: MET and METR. Since the
methanol is in excess, it will be separated out later in the process and return as a recycle stream
in METR, and MET is the methanol that needs to be purchased for each reaction. The schematic
from Aspen has HOTPROD (the feed leaving the reactor) entering the valve RMV. RMV is not
an actual unit operation in the system; its purpose is to model reducing the pressure and
temperature of the RM-1 products. This cooling step will occur in RM-1 with a cooling system.
After the reaction, the DMT, ethylene glycol (EG), methanol, and oligomers from CLDPROD
will enter the first distillation column DM-1. DMT has a boiling point of 550℉, and EG and
15
methanol have boiling points of 388℉ and 149℉, respectively. Given the design conditions from
Aspen (Appendix F), the condenser will operate at 219˚F and the reboiler will operate ate 544˚F.
DM-1 will have 57 stages. A 99% pure DMT product is expected to be collected from DM-1.
Because EG and methanol will enter DM-2 where the ethylene glycol product will be extracted.
DM-2 will have a reboiler that operates at 321˚F and a condenser than operates ate 147˚F.
According the Aspen file in Appendix F, 19 stages would be required to distill the methanol
from the ethylene glycol product.
Figure 6: Methanolysis Process Flow Diagram
Table 5 show the mass balance comparing the feed and product flows per day. One important
assumption made to develop this mass balance is that PET completely depolymerized into DMT
and EG products. This would be unlikely. While it is true that full PET polymers would not be
present after the reaction, other chains with more repeating units than DMT would be present.
These would also be present in the DMT outlet stream. Additionally, the washing does not have
100% efficiency in removing dirt, and there would be a minimal amount of dirt particles present.
Therefore, the DMT stream will likely have more than just EG present and the EG stream will
certainly not be 100% pure. METR will also be contaminated with some of the product streams.
Because Aspen cannot model the reaction with the correct molar conversion ratios (1:1
conversion for everything is expected but Aspen has to be modeled with 6 PET and 20 methanol
yields 5 DMT and 15 EG for proper molar balance), many assumptions had to be made to
generate the expected conversions. All the DMT was assumed to come out in the DMT stream
from DM-1, and the 99% purity was calculated assuming EG also came out in the bottoms. All
the EG came out in the EG stream from DM-2 and all the methanol comes out in METR. This is
not actually the case, but due to the large differences in boiling points it is probable that the
contamination of other species in these streams is negligible compared to the component of
interest. These are the values that are closest to what would be purchased or seen in the real
process and will be used for the calculation of expenses. A more detailed version of this expected
balance and the Aspen balance can be found in Appendix C.
16
Table 5: Methanolysis Overall Mass Balance
Reactants and Products
Inlet Stream (tons/day) Outlet Streams (tons/day)
Material PET MET METR DMT EG
PET 52 9 303 0 0
Methanol 0 0 0 0 0
DMT 0 0 0 52.5 0
EG 0 0 0 0.2 16.6
Table 6 shows the utility requirements for each of the unit operations from Figure 6. These
results are based on the duty requirements from Aspen, but it is being assumed these are the
energy requirements required for heating and cooling all the necessary elements for each unit.
Table 6: Utility Requirements for Methanolysis Unit Operations
Btu/hr kWh/yr
RM-1 16924500 39878908.25
DM-1 11858140 27941131.32
DM-2 13839580 32609964.31
(Damiana)
This process addresses the scope of transforming waste plastic into a value-added product
adequately, solving the problem of unusable waste plastic. It has been shown that it is
technologically feasible to prepare, sort, and recycle or transform waste plastic into useable
products rather than simply sending them to a landfill. A more sustainable approach would be
able to completely recycle more plastic types than just PET, but the pyrolysis reaction is
providing fuel which will lower the total amount of crude oil removed from the earth while the
PVC is still being used, albeit for a lower grade use. (Maxon)
V. Design alternatives Some alternatives to the base case design included using granulators in front of the methanolysis
and pyrolysis process. These were eventually removed for two reasons. Granulation is not
necessary for these processes to be run efficiently and forgoing the granulators would be more
cost effective. (Damiana)
Another alternative was to use higher density washing fluids in the friction washer. This would
allow for 99% of the contaminants to be removed, rather than 95% using high-pressured water.
However, 95% efficiency was considered sufficient for this process and was more cost effective
because water is cheaper. Running the friction washer as a batch process was considered, but
ultimately rejected, because the process would not be fast enough to keep up with the feedstock
flowrate. Wetted granulation, or granulating with water present, was briefly considered. Water
works as a lubricant and allows for less friction in the plastic as size is being reduced and
requires less maintenance on the granulator’s blades. Dry granulation was ultimately picked as to
avoid a second drying process. (Anders)
Typical recycling plants use density-based separation processes. Float-sinks are used to separate
PP and PE from other plastics using water because PP and PE are less dense than water. The PP
17
and PE are further separated using an air sifter. The air sifter sorts high-density polyethylene
(HDPE) from low-density polyethylene (LDPE). The problem with this method is that a
relatively low degree of separation is achieved, and it is not necessary to separate the HDPE and
LDPE. Several types of plastic compose the sink fraction, and this heterogeneous mixture is
often used as a secondary raw material. However, the chemolysis and pyrolysis reactions that
this plant is based around have low tolerances for contaminants, and certain polymers such as
PVC pose environmental hazards if combusted. (Nunzio)
An NRT ColorPlus sorter was considered for separating colored PET from clear PET with an
accuracy of 95% (4R Sustainability, 2011). Like the SpydIR-R, the ColorPlus also has a
maximum throughput of eight tons per hour (National Recovery Technologies, 2017). While
methanolysis does not have any issues processing mixed PET, the final product is discolored
because of the dyes used in colored PET. The separation would not have been economically
feasible because of the additional equipment that would have been required. The colored PET
would have to either be processed in its own methanolysis process or alternated with clear PET
in the existing process stream. Both options were not economically sensible compared to the
base case due to equipment costs or downtime losses. (Nunzio)
Some other alternatives for the pyrolysis process include using a thermal cracking reactor rather
than a catalytic cracking reactor. If the price of catalyst is more than the price of a fuel like
natural gas, then a thermal cracking reactor would be a better option. Looking at the current price
which is very low due to the stock market crash, a thermal cracking reactor would be more
beneficial in the short term, but over a long lifetime, an FCC reactor will likely be more
advantageous as fuel prices begin to increase. Another possible alternative includes using a
fractionating distillation column over the sets of condensers and separators. The distillation
column will likely produce more pure products; however, it will be a larger operational and
capital cost. Finally, designing and creating one large FCC reactor would suit our plant needs
better, rather than having two separate reactors. Information on the efficiency, percentage of
products, amount of emission, and many other important details is currently unknown for sizing
this large of a reactor. (Maxon)
Additionally, the problems associated with outsourcing a substantial amount of PET provided
economic difficulties due to the cost of outsourcing. PET could be included in pyrolysis as well,
but part of the design scope is to develop a circular recycling process (creating plastics for reuse
to reduce new plastic production). The technology is available to chemically recycle PET and
that is what the base case addresses. Also, it was originally thought that PET plastics should be
separated by color to retain economic value, but this caused difficulties with running the process
and cleaning the units to prevent color contamination. All plastics of all colors will run through
the process and produce a darker product. This will reduce the value of the product, but it makes
more sense from an engineering standpoint to be able to process all the colors at once rather than
trying to separate them. The dyes could be removed in a separate process, but this is addressed in
the future work section. Finally, the operating temperatures for DM-1 tower are close to the
temperatures for pyrolysis. The product would be ruined if it were pyrolyzed, but a vacuum
pressure could be used in the column to reduce this possibility. However, good engineering
maintenance can appropriately monitor the temperature. The main reason the higher pressure
was favored was because this modelling option gave a more reasonable numbers of trays in
distillation column design.
18
Potential alternatives also included using PVC in the pyrolysis process. As mentioned
previously, PVC will simply be granulated and sold because the high temperature in the reactor
will cause the formation of chlorides that are harmful to the environment and will degrade the
catalyst. Other plants are currently using this method, but avoiding the dangers associated with
PVC processing currently outweighs the potential to create more fuels. (Damiana)
VI. Permitting and Environmental Concerns While this is a recycling plant that is designed to help improve the environment, there are still
several areas in which waste is produced. For the pyrolysis reactors, which have been designed
based off the reactors used in a plant near Niagara Falls, NY, the air emissions include
particulate matter, carbon dioxide, nitrogen oxides, hydrocarbons and VOC’s. That process
yields approximately 0.29 pounds of carbon equivalents and 2.41 pounds of NOx emitted for
every ton of waste plastic. It was not required to install emissions control technologies due to the
relatively cleanliness of the process (RTI International, 2012). Appendix D: Detailed Pyrolysis
Emission contains more information about amounts of each emission type produced when the
pyrolysis input is 55 tons/day. Table 7: Pyrolysis Reactor Emissions summarizes this
information.
Table 7: Pyrolysis Reactor Emissions
Emissions generated: lbs/day tons/year
PM 2.09 0.35
CO2 equivalents 15.95 2.67
Hydrocarbons 0.019 0.0031
SO2 0.77 0.13
NOx 132.55 22.20
CO 15.95 2.67
VOC 0.94 0.16
HAP 0.019 0.0031
NOx is clearly the largest emission produced by the pyrolysis reactors at 22.20 tons each year.
The next largest are the CO2 equivalents and the CO emissions, each at 2.67 tons/year. While
RTI International states that the pyrolysis reactor does not need air control, some of the best
available air control technologies (BACTs) that could be used are low NOx burners (LNB),
overfire air (OFA), burning out of service (BOOS), and flue gas recirculation (FGR). All of these
are commonly used for utility boilers which are a close model for the pyrolysis reactors used in
this process; however, each type of control has a different level of efficiency, % of NOx removed,
and cost. For example, LNB control on a PC-Wall boiler type would be 45-60% efficient,
removes 35-55% of the NOx present, and costs $160-450 per ton of air passed through the
controller (United States).
Outside of the air emissions, the pyrolysis also produces nonhazardous waste at 2.5 tons/day or
837.5 tons/year. This nonhazardous waste does not have any specific environmental concerns but
does fill landfills which can become a problem in the future as waste disposal becomes a larger
issue.
19
Another environmental concern is the amount of CO2 produced during the generation of
electricity which will be required to run the plant. Calculations based on natural gas burning for
power generation can be found in Appendix J: Environmental Impact Calculations. With
103,677,944 kWh/year of electricity needed and using only natural gas, 19,244 metric tons of
CO2 will be released into the atmosphere each year. Since the plant will not generate its own
electricity, control methods for this will not be discussed further. (Maxon)
Several general permits will need to be obtained to build in New York City. First, a boiler permit
will be needed for both the pyrolysis and methanolysis processes. This permit allows for boilers
to be built and operated in city limits. To obtain the boiler permit, all boilers must be in
compliance with the Building Code and all regulations. Next, a concrete permit is required to
build in New York City. This ensures that the building meets the project’s structural design
requirements. Also, an electrical permit is needed. Any electrical work, including handling of
wires, needs an electrical permit. Another important permit is general liability insurance. In the
case of an accident during construction, general liability insurance will cover the expenses that
otherwise would fall on the company. Finally, any plumbing work being done that involves
alteration, relocation, or permanent removal of piping must be supervised by a licensed plumber.
The licensed plumber must obtain the permit and arrange for any necessary tests and
inspections (nyc.gov, 2020). (Anders)
VII. Safety and Risk Analysis The major safety risks arise from both the pyrolysis and methanolysis reactors as well as the
equipment closest to them due to the high pressure and temperatures they are operating at.
Extreme caution should be taken when working around these unit operations because a simple
leak could result in dangerously hot fluids being released. As shown in Appendix G: Complete
HAZOP Analysis, this release could harm operators, increase the chance of an external fire, or
damage the equipment surrounding the reactors which could initiate a chain reaction. There is
extra concern due to the high flammability of both the methanol reactant and the pyrolysis fuel
product. The possibility of an explosion or implosion results in further danger as these events
could be catastrophic for the whole plant. Other safety concerns include malfunctions of the IR
sorters resulting in more or less material being sent to a particular process. That could result in
safety issues such as burst pipes, released reagents, pump cavitation, and/or toxic gas produced.
Furthermore, plastic preparation steps do not include the project’s primary hazards, but safety
precautions need to be taken such as having preventative measures in place in case of a leak or
spill of water. The hazard of cleaning the sharp blades incorporated in the shedders and
granulator will be mediated by procedural safety training. Several reagents are highly flammable
including methanol and crude oil as shown in Appendix H: SDS files. Appendix H contains all
other reagents as well, while complex compositions such as the crude oil have been described by
a combination of several components rather than a comprehensive list.
The major design improvements include monitoring systems and automated shutdown processes
and procedures. Automated safety systems such as pressure relief valves will be placed on
reactors, distillation columns, condensers, and separators to ensure they are properly vented once
a pressure deviates from the standard range. Other measurement tools such as flow meters will
20
be installed before major unit operations to monitor in case of a pipe burst or sorting
malfunction. Once a flowrate outside of the desired setpoint is detected, procedures to check
measurements and adjust the system will take place. This will require a comprehensive
monitoring and control system. Other adjustments include a purge stream for the friction washer
to ensure the water flow does not become too high. A barrier and guard were added to the
shredder to ensure operators stay a safe distance from the blades. Another precaution that has
been added to the design is fire protection. Supporting beams and piping must be able to handle
extreme temperatures without losing strength or deteriorating. Unit operations will be placed safe
distances from one another to ensure fire damage does not spread from one unit operation to
another. Finally, maintenance and integrity testing procedures will need to be created and
implemented to monitor any cracks or potential weak areas in the process equipment. (Maxon
and Anders)
VIII. Project Economics Several assumptions were made to analyze the economic feasibility of this plant. The plant will
only operate for eleven months out of the year (335 days) and leave the twelfth month for
maintenance, repairs, and cleaning. Plant construction is estimated to take one year, and the plant
will have a 20-year lifetime. The tax rate was set at 21%, and a MACRS5 depreciation was used.
A MARR of 20 % was chosen by analyzing Table 8-1 from Peters et al. and determining this
plant has a medium risk level (1968). A medium risk level was chosen because recycling is an
established market, but this plant uses newer technologies and designs. Table 8 shows the
estimation of equipment pricing. All costs have been updated to July 2019.
Table 8: Main equipment quantity, pricing, and total cost
Equipment Quantity Updated Pricing ($) Total ($)
Plastic Preparation
(Anders)
Prewasher 1 23,000 23,000
Friction washer 1 36,000 36,000
Dryer 1 28,000 28,000
Shredder 3 17,000 51,000
Granulator 1 45,000 45,000
Sorting (Nunzio)
IR sorter 3 255,273 765,819
Methanolysis
(Damiana)
RM-1 (reactor) 5 726,081 3,630,404
DM-1 (distillation) 1 421,804 421,804
DM-2 (distillation) 1 229,513 229,513
Pyrolysis (Maxon)
Reactor 2 587,000 1,174,000
Cond1 1 20,133 20,133
Cond2 1 7,500 7,500
Cond3 1 7,500 7,500
Sep1 1 5,586 5,586
21
Sep2 1 4,638 4,638
Sep3 1 3,584 3,584
Heat Exchanger 1 3,097 3,097
Total 6,456,577
All the equipment for the plastic preparation, sorting stage, and the pyrolysis reactor were found
from online vendors. The main factors for selecting equipment were efficiency and sizing;
whereas, other equipment for pyrolysis and methanolysis were obtained from Peters et al. cost
figures and then updated to July 2019 using the CEPCI index (Lozowski). Table 9 below
summarizes the name, location found, and description of each equipment cost estimation that
came from Peters et al. (1968). For the pyrolysis equipment that needed to be sized, calculations
to determine their sizes can be found in Appendix I: Pyrolysis Equipment Sizing. Equipment
sizing for methanolysis was based on results generated from the Aspen files in Appendix F, but
the calculation is also shown in Appendix I: Methanolysis Equipment and Products; this includes
the required volume for the reactors and the number of trays needed for the distillation columns.
Table 9: Equipment description and location
Equipment
Name
Location Description
Prewasher (Lindner, 2018) Effectively separates abrasive
matter and prepares the material
for all following processes. Can
process 5 tons/hr.
Friction
Washer
(Polestar Machinery, 2019) Uses a high-pressure spray,
impinging on the surface of the
plastic as it is transferred up an
incline conveyor.
Dryer (Rotajet Recycling, 2019). High volume hot air blower. The
used hot air is recirculated for
reuse, ensuring an operating
temperature is achieved in a
short cycle time.
Shredder (Shanjie Machinery, 2019) Cardan shaft drives, double
sidewalls, reversible counter
knives, hydraulic swing-up
screen carriages, rotatable
screens, and externally
adjustable counter knives.
Granulator (Plastic Recycling Machine, 2019) Rotor bearings, knife mount,
rotor shaft, and adjustable output
sizes.
IR Sorter (National Recovery Technologies, 2019) Infrared sorting system to sort
out target plastics to be recycled.
8 t/hr throughput. Detection
accuracy of 99%.
22
RM-1 (“Matches' Reactor Cost”) Glass lined carbon steel with
5000-gal capacity and 1500 psi
pressure capacity.
DM-1 Figure 15-15
61 trays, 3 ft diameter and
stainless steel
DM-2 Figure 15-15
6 trays, 3 ft diameter, and
stainless steel
Pyrolysis
Reactor
(RTI International, 2012). 20 tons/day capacity, 92%
recovery, 1000 ft2 footprint
Pyrolysis
Condensers:
Cond1,
Cond2, Cond3
Figure 14-29 316 stainless-steel housing with
a 48, 2.8, 0.3 m2 heat transfer
area respectively
Pyrolysis
Separators:
Sep1, Sep2,
Sep3
(“Separator Cost Estimate”). Internal diameters of 12, 9, 6 in
respectively
Pyrolysis Heat
Exchanger
Figure 14-15 Double pipe heat exchanger with
stainless-steel tubes and a carbon
shell operating at 600 psi and a
heat transfer area of 1.45 m2
Given the purchased cost of the major equipment in Table 8 above, the total and fixed capital
investment was calculated using the solid-processing plant design factors from Figure 6.6 in
Peters et al and is shown in Table 11 below. The working capital given in Peters et al. uses a
factor of 0.7 of the delivered equipment costs which would result in $ 4.88 million (1968).
However, to more accurately estimate the necessary working capital for this plant, 3 months
from the first year expenses was used and calculated to be $14.71 million.
Table 10: Capital investment estimation based on delivered-equipment cost Fraction of delivered
equipment for a solid
processing plant
User
values
Calculated values $
Direct costs
Purchased equipment
6,456,577
Delivery, percent of purchased
equipment
0.1 645,658
subtotal: delivered equipment
7,102,235
Purchased equipment installation 0.45
3,196,006
Instrumentation and controls
(installed)
0.18
1,278,402
Piping (installed) 0.16
1,136,358
Electrical Systems (installed) 0.1
710,223
Buildings (including services) 0.25
1,775,559
Yard improvements 0.15
1,065,335
23
Fraction of delivered
equipment for a solid
processing plant
User
values
Calculated values $
Service Facilities 0.4
2,840,894
Total direct cost
19,105,012
Indirect costs
Engineering and supervision 0.33
2,343,738
Construction expenses 0.39
2,769,872
Legal expenses 0.04
284,083
Contractor's fee 0.17
1,207,380
Contingency 0.35
2,485,782
Total indirect cost
9,090,861
Fixed capital investment (FCI)
28,195,873
Working Capital 3 months of year 1
expenses
13,501,074
Total Capital Investment (TCI)
41,696,947
Table 11 shows the estimated operating cost, raw material pricing, and variable costs such as
insurance and taxes. The prices for methanol and PET were found in the ICIS database. The
catalyst amount was determined using the ratio of 10 kt/a (Ragaert et al., 2017) and prices were
found at “Z2SM-5 Series Zeolite (MFI) Powder.” Operating costs were calculated assuming that
15 operators will work a total of 8040 hours in a year at $20 per hour. All other costs were found
using factors given in Figure 6-8 of Peters et al. (1968). The current calculated operating costs is
$16.68 million a year.
Table 11: Annual operating costs assuming plant runs at 100% capacity Suggested
Factor
Rate or
quantity
Units Cost
($)
Units Calculated
values $M
Raw materials
Methanol (Year 1)
104,520 ton/yr 376 $/ton 39
Methanol (Year 2 –
End)
3,015 ton/yr 376 $/ton 1.13
PET
48.7 ton/yr 300 $/ton 0.01
Operating labor 8040 hr/yr 15 operators 20 $/hr 2.412
Operating supervision 0.15 of
operating
labor
0.36
Utilities
Cooling water
19,381 cft/yr 3.99 $/100cft 0.08
Process water
316,800 cft/yr 3.99 $/100cft 0.01
24
Suggested
Factor
Rate or
quantity
Units Cost
($)
Units Calculated
values $M
Electricity
103,677,944 kWh/yr 0.07 $/kwh 7.225
Nonhazardous waste
33.5 ton/yr $ 51 $/ton 0.002
Maintenance and
repairs
0.07 of FCI
1.974
Operating supplies 0.15 of
maintenance
and repairs
0.296
Catalysts and solvents
2.407
Total variable
production costs
15.838
Property taxes 0.02 of FCI
$ 0.564
Insurance 0.01 of FCI
$ 0.282
Fixed charges
$ 0.846
Total product cost
$ 16.68
To estimate the annual revenue produced, the quantity of major products and byproducts were
determined, the prices for each were researched, and then multiplied together to get a total
revenue. The price value for the DMT was given by ICIS while the price for motor gasoline, fuel
No. 2, and fuel No. 6 were found at “U.S. Energy Information Administration - EIA -
Independent Statistics and Analysis.” These prices were then lowered by 5% to account for the
cost of sending the fuel to a refinery rather than selling it at wholesale value. As for the
byproducts, the PVC pricing was found at “Transparent PVC Granules,” while the EG price was
given by ICIS. Both the DMT and EG prices were reduced 20% from real values due to the
decrease in value of the product from the combination of dyes. A large amount of methanol will
be required during year one, but most of this can be reused which lowers the reoccurring
operational costs. After totaling the amount received from each product, a yearly revenue of
$28.89 million was determined for every year but year one. The revenue is summarized in Table
12. (Maxon)
Table 12: Total revenue for major products and byproducts
Products Quantity (ton/yr) Price ($/ton) Yearly Revenue $
DMT 17,654.5 1005 17,742,490
Motor Gasoline 4,026 477 1,919,278
Fuel No. 2 5,176 500 2,589,786
Fuel No. 6 2,300 378 868,861
Byproducts
PVC 3,819 417 1,592,523
EG 5,561 752 4,181,961
Total
28,894,900
Tables 13-15 show a cash flow sheet to investigate the economic feasibility of the mixed plastic
recycling plant over its lifespan. Note that all tables are created using millions of US dollars as a
25
currency unit. The MARR was assumed to be 20%. The NPV0 of project is $131.72 million with
a payback period of just under 9 years. The NPV20 is –$35.13 million. The IRR was calculated
to be 10%. This is much less than the MARR and makes this an unfavorable project. As
expected, recycling is not a lucrative industry in the current economy; therefore, government
support will be required to be economically feasible over time. (Nunzio)
Table 13: Cash flow sheet, years 0 to 10.
Tax Rate 0.21
Year 0 1 2 3 4 5 6 7 8 9 10
FCI -28.20
Working
Capital
-14.71
StartUp -2.82
MACRS5
Factors
0.2 0.32 0.192 0.1152 0.1152 0.0576
Depr
Amount
5.64 9.02 5.41 3.25 3.25 1.62
Depr
Credit
1.18 1.89 1.14 0.68 0.68 0.34
Revenue 28.89 28.89 28.89 28.89 28.89 28.89 28.89 28.89 28.89 28.89
Production
Expenses
-44.52 55.98 16.68 16.68 16.68 16.68 16.68 16.68 16.68 16.68 16.68
Revenue-
Expenses
-44.52 -27.09 12.21 12.21 12.21 12.21 12.21 12.21 12.21 12.21 12.21
Tax
Liability
-5.69 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56
Cash Flow -58.02 -20.22 11.54 10.78 10.33 10.33 9.99 9.65 9.65 9.65 9.65
CumCF -58.02 -78.23 -66.69 -55.91 -45.58 -35.25 -25.26 -15.62 -5.97 3.67 13.32
DF20 100% 83% 69% 58% 48% 40% 33% 28% 23% 19% 16%
PV20 -58.02 -16.85 8.01 6.24 4.98 4.15 3.34 2.69 2.24 1.87 1.56
CumPV20 -58.02 -74.86 -66.85 -60.61 -55.63 -51.48 -48.13 -45.44 -43.20 -41.33 -39.77
Table 14: Cash flow sheet, years 11 to 21
Tax Rate 0.21
Year 11 12 13 14 15 16 17 18 19 20 21
FCI
Working
Capital
14.71
StartUp
MACRS5
Factors
Depr
Amount
Depr
Credit
26
Revenue 28.89 28.89 28.89 28.89 28.89 28.89 28.89 28.89 28.89 28.89 28.89
Production
Expenses
16.68 16.68 16.68 16.68 16.68 16.68 16.68 16.68 16.68 16.68 16.68
Revenue-
Expenses
12.21 12.21 12.21 12.21 12.21 12.21 12.21 12.21 12.21 12.21 12.21
Tax
Liability
2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56 2.56
Cash Flow 9.65 9.65 9.65 9.65 9.65 9.65 9.65 9.65 9.65 9.65 23.15
CumCF 22.97 32.61 42.26 51.91 61.55 71.20 80.85 90.49 100.14 109.78 132.93
DF20 13% 11% 9% 8% 6% 5% 5% 4% 3% 3% 2%
PV20 1.30 1.08 0.90 0.75 0.63 0.52 0.43 0.36 0.30 0.25 0.50
CumPV20 -38.47 -37.39 -36.49 -35.74 -35.11 -34.59 -34.15 -33.79 -33.49 -33.24 -32.73
Table 15: Cash flow sheet summary
NPV0 +134.72
NPV20 -35.13
IRR 10%
PBP (years) 9
MARR 20%
Figures 7 through 9 show sensitivity plots for the above analyses. All sensitivities were chosen to
be ± 40% of the original NPV20. Figures 7 illustrates a linear relationship between an increase in
revenue and an increase in NPV20 while Figure 8 has an inverse relationship in comparison. As
the operating costs increase the NPV20 decrease in a linear fashion. Figure 9 illustrates a
generally linear relationship whereas the FCI increases the NPV20 decrease; however, Figure 7
and 8 have a much larger slope resulting in the operating cost and revenue being more sensitive
than the FCI. (Maxon)
27
Figure 7: Sensitivity plot analyzing the revenue effect on the NPV20.
Figure 8: Sensitivity plot analyzing the operating cost effect on the NPV20.
28
Figure 9: Sensitivity plot analyzing the FCI effect on NPV20.
IX. Global Impacts Plastic waste has had many negative environmental impacts, especially if it is disposed of
improperly. The base case for this design places the plant in New York partially because New
York City is considered the most wasteful city in the world (Adler, 2016). New York City
produces approximately 4.4 million tons of plastic every year, and the capacity of this plant
would not account for even 1% of this waste. Better recycling programs or larger plant capacities
or multiple plants operating could make a bigger impact. However, the reduction of any plastic
waste being put in the environment is an important step to reducing plastic waste in general.
Additionally, wide scale use of plastic recycling plants could impact the oil industry if used more
widely. While it is difficult to estimate how much oil mined every year goes towards the plastic
industry (crude oil must be refined before becoming plastic), some estimates say approximately
4% of global oil production is directly tied to plastic. If methanolysis were able to be used widely
so plastic could be reused, oil production for this plastic could potentially stop. Oil drilling may
lead to water contamination and air pollution, and even if small, circular recycling processes will
reduce this if less oil needs to be recovered. Pyrolysis may not contribute as much to this since
the oil will be burned for energy anyways. When this product is burned for energy, it will
contribute to air pollution. The biggest environmental issue internally is CO2 emissions from the
electricity needed to run the plant which has been assumed to be generated using natural gas.
Renewable and environmentally friendly energy sources (such as solar or wind) could be
considered to reduce this impact, but the capital cost of the project already exceeds the ability to
pay it back.
On a local level, the biggest impacts on the plant would be jobs and transportation. The plant has
a large capacity of plastic that can be processed, but it first must be transported to the location.
Due to the highly automated nature of the process, 15 operators per shift and several supervisors
will be necessary. Recycling will become economically advantageous at a local and national
29
level many years in the future as natural resources begin to decline and the cost of disposal
increases if space for landfill waste runs low. (Damiana)
Chemical recycling of plastic reduces the amount of plastic that is landfilled and promotes a
more circular lifecycle for plastic polymers. Current recycling plants often utilize mechanical
recycling methods that extend the lifespan of polymers but do not reduce the overall amount of
plastic waste. Chemical recycling also avoids having to downcycle plastic waste because the
plastic types are separated with a high specificity. (Nunzio)
X. Conclusions & Recommendations In conclusion, this plant meets most of the above-mentioned design scope and goals. It reduces
the amount of plastic being sent into landfills and the environment by 18,500 tons of mixed
plastic waste every year and an additional 16,415 tons of PET. Using IR sorting and chemical
recycling, all seven types of municipal plastics can be processed in a way to produce profitable
products. Although the sale of DMT, ethylene glycol, fuel oils, and granulated PVC can be
lucrative, the net present value of the plant is about –$35.13 million after 20 years with a 20%
discount rate. Since this project’s IRR is 10%, which is less than the 20% MARR, this is not an
economically favorable project. The payback period for this venture was found to be just under 9
years. Typical recycling plants rarely have large profit margins due to high production costs and
low product prices. Recommendations include use of a gate fee and government subsidy to
generate an additional $9.09 million in annual revenue. Such an increase would improve the IRR
to 20%. (Anders and Nunzio)
XI. Future work The current methanolysis process does not remove dyes from the final products, resulting in
discoloration. Information provided by the Fraunhofer-Institut shows the CreaSolv process to be
a possible route to remove dyes from the PET. Normally the CreaSolv process is used to dissolve
a specific polymer from a mixture. Further tests would need to be run to determine if CreaSolv
can be used for de-dyeing PET. If successful, the EG and DMT would be free of dyes and could
be sold at a higher price. (Nunzio)
Possible governmental assistance needs to be researched to determine if any tax cuts, incentives,
or special loans can be offered. It has been mentioned that some landfills will pay for others to
take and process their waste, so further research into this will be done to hopefully reduce the
cost of PET resourcing. A report by Axion Consulting (2009) determined that a gate fee was an
option to reach an IRR of 15% for a UK recycling project. Gate fees could be implemented at a
similar rate to landfills and still be competitive because of the positive PR associated with
recycling. Both would make the project more economically feasible. Expansion of the
methanolysis process should also be considered as it can be very profitable if more PET can be
processed. If the project is proven to be economically feasible, then PI&D plans would need to
be created before construction could begin. (Maxon and Nunzio)
XII. Acknowledgements We would like to acknowledge our instructor and advisor, Dr. David Bell, for his valuable
knowledge and the sources he shared to get us started on this project. (Anders)
30
XIII. References 4R Sustainability. “Demingling the mix: An assessment of commercially available automated
sorting technology.” American Chemistry Council, 2 ed., Jan. 2011,
https://plastics.americanchemistry.com/Assessment-of-Commercially-Available-
Automated-Sorting-Technology/.
Achilias, D. S., et al. "Chemical recycling of plastic wastes made from polyethylene (LDPE and
HDPE) and polypropylene (PP)." Journal of Hazardous Materials 149.3 (2007): 536-
542.
Adler, Ben. “Which Is the World's Most Wasteful City?” The Guardian, Guardian News and
Media, 27 Oct. 2016, www.theguardian.com/cities/2016/oct/27/which-is-the-worlds-
most-wasteful-city.
Aguado Jose, and David P. Serrano. Feedstock Recycling of Plastic Wastes. Royal Society of
Chemistry, 2007,
Genta (200
Almeida, Débora, and Maria de Fátima Marques. "Thermal and catalytic pyrolysis of plastic
waste." Polímeros 26.1 (2016): 4451.
https://www.sciencedirect.com/science/article/pii/S1110062115000148
Al-Sabagh, A.m., et al. “Greener Routes for Recycling of Polyethylene Terephthalate.” Egyptian
Journal of Petroleum, vol. 25, no. 1, 2016, pp. 53–64., doi:10.1016/j.ejpe.2015.03.001.
Axion Consulting. “A Financial Assessment of Recycling Mixed Plastics in the UK.” Waste and
Resources Action Programme, June 2009, http://www.wrap.org.uk/collections-and-
reprocessing/dry-materials/plastics/reports/financial-assessment-mixed-plastics-recycling
Bodzay, B. & Banhegyi, Gyorgy. (2017). Polymer waste: Controlled breakdown or recycling?.
International Journal of Design Sciences and Technology. 22. 109-138.
Carta, Daniela, et al. “Chemical Recycling of Poly(Ethylene Terephthalate) (Pet) by Hydrolysis
and Glycolysis.” Environmental Science and Pollution Research, vol. 10, no. 6, 2003, pp.
390–394., doi:10.1065/espr2001.12.104.8.
“Chemical Prices.” Icis,
https://www.icis.com/explore/resources/news/2004/03/04/560887/chemical-prices/.
“Continuous Thermal Decomposition Plant (TDP-2-800): Thermal Decomposition Plant.” Ipec-
Index > https://tdplant.com/equipments/continuous-thermal-decomposition-plant-tdp-
2?utm_source=google&utm_medium=cpc&utm_campaign=poiskovaya-
vysokochastotniki-usa-plastik&utm_content=384385802856&utm_term=convert plastic
to
oil&gclid=Cj0KCQiAk7TuBRDQARIsAMRrfUafJahm9K8LKdfkKkcvnnhufueNBOVf
pBGw_KdAOzZFIPolQNWPbHcaAmTSEALw_wcB.
“Eastman Offers Innovative Recycling Technology for Polyesters.” Eastman Chemical
Company, Mar. 2019,
https://www.eastman.com/Company/News_Center/2019/Pages/Eastman-offers-
innovative-recycling-technology-for-polyesters.aspx.
Environmental Research & Education Foundation (2018) “Analysis of MSW Landfill Tipping
Fees, April 2018 (Rev. ed.)”. Retrieved from www.erefdn.org, 3 May 2020.
Garforth, Arthur A., et al. “Feedstock Recycling of Polymer Wastes.” Current Opinion in Solid
State and Materials Science, vol. 8, no. 6, Dec. 2004, pp. 419–425.
ScienceDirect, doi:10.1016/j.cossms.2005.04.003.
Genta, Minoru, et al. “Development of Chemical Recycling Process for Post-Consumer PET
31
Bottles by Methanolysis in Supercritical Methanol.” Technical Review, vol. 40, no. 1,
Jan. 2003, https://www.mhi.co.jp/technology/review/pdf/e401ex/e395254.pdf.
Goodship, Vannessa. “Plastic Recycling.” Science Progress, vol. 90, no. 4, 2007, pp. 245-
268. JSTOR, doi: 10.3184/003685007X228748.
Goto, Motonobu. “Chemical Recycling of Plastics Using Sub- and Supercritical Fluids.” The
Journal of Supercritical Fluids, vol. 47, no. 3, Jan. 2009, pp. 500–507.
ScienceDirect, doi:10.1016/j.supflu.2008.10.011.
“How Plastic Recycling Equipment Works” Thomasnet. 10 Dec 2019.
https://www.thomasnet.com/articles/plastics-rubber/plastic-recycling-equipment/
Jambeck, Jenna R., et al. “Plastic Waste Inputs from Land into the Ocean.” Science, vol. 347,
no. 6223, 13 Feb. 2015, pp. 768–771., doi:10.1126/science.1260352.
Kaminsky, W., et al. “Thermal Degradation of Mixed Plastic Waste to Aromatics and Gas.”
Polymer Degradation and Stability, vol. 53, no. 2, 1996, pp. 189–197.,
doi:10.1016/0141-3910(96)00087-0.
Kannan, P., et al. "Polymer Recovery Through Selective Dissolution of Co-mingled Post-
Consumer Waste Plastics." (2017): 75-84.
Kunwar, Bidhya, et al. “Catalytic Thermal Cracking of Postconsumer Waste Plastics to Fuels. 2.
Pilot-Scale Thermochemical Conversion.” Energy & Fuels, vol. 31, no. 3, 2017, pp.
2705–2715., doi:10.1021/acs.energyfuels.6b02996.
Li, Jia, et al. “Tribo-Charging Properties of Waste Plastic Granules in Process of Tribo-
Electrostatic Separation.” Waste Management, vol. 35, 2015, pp. 36–
41., doi:10.1016/j.wasman.2014.10.001.
Lin, Yuji, and Nickolas J Themelis. “Industrial-Scale Processes for Transforming Mixed Plastic
Wastes to OIl.” Department of Earth and Environmental EngineeringFu Foundation
School of Engineering & Applied Science Columbia University, 2018
Lindner. (2018). Post-Consumer – Lindner. Retrieved September 18, 2019, from
https://www.lindner.com/system-solutions/plasticrecycling/post-consumer/
Lozowski, Dorothy. “The Chemical Engineering Plant Cost Index - Chemical
Engineering.” Chemical Engineering The Chemical Engineering Plant Cost Index
Comments, https://www.chemengonline.com/pci-home.
Matches' Reactor Cost , Matches, 2014, www.matche.com/equipcost/Reactor.html.
MSS Optical, L-VIS. 10 Dec 2019, http://www.mssoptical.com/material-sorting-
equipment/plastic-sorting-equipment/l-vis/
“National Overview: Facts and Figures on Materials, Wastes and Recycling.” EPA,
Environmental Protection Agency, 3 Dec. 2019, https://www.epa.gov/facts-and-figures-
about-materials-waste-and-recycling/national-overview-facts-and-figures-materials#13-
14Trends.
National Recovery Technologies. (2017). “Equipment.” Retrieved 2 May 2020.
http://www.nrtsorters.com/equipment/
Nyc.gov. (2020). NYC Permits. Retroeved May 3, 2020, from
https://www1.nyc.gov/site/builinds/business/permit-information-type.page
“PET Bottle Recycling - PET Bottle Washing Line: ASG Plastic Recycling Machine.” PET
Bottle Washing Line | ASG Plastic Recycling Machine, 25 Mar. 2019,
https://www.petbottlewashingline.com/pet-bottle-recycling/.
Peters, Max Stone, et al. Plant design and economics for chemical engineers. Vol. 4. New York:
McGraw-Hill, 1968.
32
“Petrochemicals, Energy, and Fertilizers Market Information: ICIS.” ICIS Explore, ICIS,
www.icis.com/explore/.
“Plastic Recycling Machine.” Plastic Granulator. 10 Dec. 2019.
https://www.plasticrecyclingmachine.net/plastic-granulator/
“Polestar Machinery.” Product description, High speed friction washer. 10 Dec. 2019,
https://www.polestarmachinery.com/product/high-speed-friction-washer/
PRI Systems. (2020). Products PRI. Retrieved November 11, 2019, from
https://prisystems.com/products/
Qian, Rose. “Tyre/ Plastic Pyrolysis Oil - Waste Oil Distillation Plant.” Beston Pyrolysis Plant,
29 Jan. 2019, https://www.bst-pyrolysis.com/waste-oil-distillation-plants/.
Ragaert, Kim, et al. “Mechanical and Chemical Recycling of Solid Plastic Waste.” Waste
Management, vol. 69, 18 Aug. 2017, pp. 24–58., doi:10.1016/j.wasman.2017.07.044.
Rahimi, AliReza, and Jeannette M. García. "Chemical recycling of waste plastics for
new materials production." Nature Reviews Chemistry 1.6 (2017): 0046.
“RecycleMorePlastic.org.” RecycleMorePlastic.org,
https://recyclemoreplastic.org/view/sortforvalue.
Reusch, William. Polymers,
https://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/polymers.htm.
“Rotajet Recycling.” Mechanical Dryers – Horizontal. 10 Dec 2019.
https://plasticwashing.co.uk/mechanical-dryer-horizontal/
RTI International (2012). Environmental and Economic Analysis of Emerging Plastics
Conversion Technologies Final Project Report. pp.1-70.
Sánchez, Arnau Carné, and Simon R. Collinson. “The Selective Recycling of Mixed Plastic
Waste of Polylactic Acid and Polyethylene Terephthalate by Control of Process
Conditions.” European Polymer Journal, vol. 47, no. 10, 2011, pp. 1970–
1976., doi:10.1016/j.eurpolymj.2011.07.013.
“Separator Cost Estimate.” Matches' Separator Cost - Air-Sweep, Cyclone, Gas-Liquid Vane,
Screw Classifier., 2014, www.matche.com/equipcost/Separator.html.
“Shanjie Machinery.” 2019 new pip shredder machinery. 10 Dec 2019.
https://hnsjmachinery.en.alibaba.com/product/62356697584-
815460511/2019_new_pipe_shredder_machinery.html
Sharuddin, Shafferina Dayana Anuar, et al. “A Review on Pyrolysis of Plastic Wastes.” Energy
Conversion and Management, vol. 115, 12 Feb. 2016, pp. 308–326.,
doi:10.1016/j.enconman.2016.02.037.
Shent, Huiting, et al. “Erratum to ‘A Review of Plastics Waste Recycling and the Flotation of
Plastics.’” Resources, Conservation and Recycling, vol. 27, no. 3, 1999, pp. 285–286.,
doi:10.1016/s0921-3449(99)00032-4.
Taverdi, K. “Improving the Mechanical Recycling and Reuse of Mixed Plastics and Polymer
Composites.” Management, Recycling and Reuse of Waste Composites, Woodhead
Publishing, 2010, pp. 281-
302. https://www.sciencedirect.com/science/article/pii/B9 781845694 62350011X?via%
3Dihub
“Transparent Pvc Granules - Buy Pvc Granules, Pvc Granules for Profiles, Soft Medical Pvc
Granules Product on Alibaba.com.” Www.alibaba.com,
https://www.alibaba.com/product-detail/transparent-pvc-
granules_527810736.html?spm=a2700.7724838.2017115.22.7cf915c2LrmJwN&s=p
33
Tullo, Alexander H. “Plastic Has a Problem; Is Chemical Recycling the Solution?” Chemical &
Engineering News, 6 Oct. 2019, https://cen.acs.org/environment/recycling/Plastic-
problem-chemical-recycling-solution/97/i39.
United States, Congress, Neuffer, Bill. “NOx CONTROLS FOR EXISTING UTILITY
BOILERS.” NOx CONTROLS FOR EXISTING UTILITY BOILERS.
“U.S. Energy Information Administration - EIA - Independent Statistics and Analysis.” U.S.
Energy Information Administration (EIA) - Petroleum & Other Liquids,
https://www.eia.gov/petroleum/.
“U.S. Energy Information Administration - EIA - Independent Statistics and Analysis.” Fluid
Catalytic Cracking Is an Important Step in Producing Gasoline - Today in Energy - U.S.
Energy Information Administration (EIA),
https://www.eia.gov/todayinenergy/detail.php?id=9150.
Wang, Hui, Zhang, Y., Wang, C. “Surface modification and selective flotation of waste plastics
for effective recycling – a review.” Separation and Purification Technology, vol. 226,
2019, pp. 75-94. Elsevier B. V., doi: 10.1016/j.seppur.2019.05.052
Waste Plastic Pyrolysis Plant For Sale - Plastic Pyrolysis Machine Price
https://www.bst-pyrolysis.com/waste-plastic-pyrolysis-plant/
“Waste Plastic Pyrolysis Plant For Sale - Plastic Pyrolysis Machine Price.” Beston Pyrolysis
Plant, https://www.bst-pyrolysis.com/waste-plastic-pyrolysis-plant/.
“Waste Plastics Pyrolysis Plant.” Lingfine Machinery, 2018, https://www.lingfine.com/waste-
plastics-pyrolysis-plant.html.
“WHAT A WASTE 2.0.” Trends in Solid Waste Management,
http://datatopics.worldbank.org/what-a-waste/trends_in_solid_waste_management.html.
Wimsattt, K. (2016). Recycling Facts, Retrieved October 15, 2019, from
https://www.grownyc.org/recycling/facts
Yang, Yong, et al. “Study on Methanolytic Depolymerization of PET with Supercritical
Methanol for Chemical Recycling.” Polymer Degradation and Stability, vol. 75, no. 1,
10 Dec. 2001, pp. 185–191., doi:https://doi.org/10.1016/S0141-3910(01)00217-8.
Yong, Yang, et al. “Methanolysis of Poly(Ethylene Terephthalate) in Supercritical Phase.” The
Chinese Journal of Process Engineering, vol. 1, no. 1, Jan. 2001,
https://pdfs.semanticscholar.org/8067/18dc4ca56af704c68f569b5b9ad3d7831f19.pdf.
Zhao, Yi-Bo, Lv, X., Ni, H. “Solvent-based separation and recycling of waste plastics: A
review.” Chemosphere, vol. 209, 2018, pp. 707-720. Elsevier Ltd.,
doi: 10.1016/j.chemosphere.2018.06.095
Zhu, Shichao, Chen, H., Wang, M., Guo, X., Lei, Y., Jin, G. “Plastic solid waste identification
system based on near infrared spectroscopy in combination with support vector
machine.” Advanced Industrial and Engineering Polymer Research, vol. 2, 2019, pp. 77-
81. Elsevier Ltd., https://doi.org/10.1016/j.aiepr.2019.04.001
“ZSM-5 Series Zeiolite (MFI) Powder.” ACS Material Advanced Chemicals Supplier, ACS
Material LLC, 2020, www.acsmaterial.com/zsm-5-series-zeolite-powder.html.
XIV. Appendices Appendix A: Plastic Details
All are main 7 types of plastics are thermoplastics
34
Plastic Name: Polyethylene Terephthalate PET
Plastic Type: type 1
Density: 1.38 g/cm^3
MW:
Monomer Structure:
Polymer Formation: condensation
Uses: fibers for clothing, containers for liquids/foods, thermoforming for manufacturing,
combination with glass for engineering resin
Melting Point: 260 C
Other recycling considerations:
Only type that could be processed via chemolysis
Current washing and treatment technique: (“PET Bottle Recycling - PET Bottle Washing Line:
ASG Plastic Recycling Machine,” 2019)
(Reusch)
Plastic Name: High Density Polyethylene HDPE
Plastic Type: type 2
Density: .95 g/cm^3
MW: 2*10^5-3*10^6
Monomer Structure:
Polymer Formation: breaking of double bonds
Uses: storage containers, lumber, outdoor furniture, playground equipment, automobile parts,
trash cans
Melting Point: 130 C
Other recycling considerations: Only difference between HDPE and LDPE is degree of
branching
Plastic Name: Polyvinyl Chloride PVC
Plastic Type: type 3
Density: 1.45 g/cm^3
Monomer Structure:
35
Polymer Formation: chlorine reacts with double bond
Uses: Pipe and in profile applications such as doors and windows. It is also used in making
bottles, non-food packaging, food-covering sheets, debit/credit cards,
Melting Point: 100-260 C
Other recycling considerations:
Must be separated from all others during mechanical separation
Currently recycled using pyrolysis, hydrolysis and heating are used to convert the waste into its
chemical components. The resulting products – sodium chloride, calcium chloride, hydrocarbon
products and heavy metals to name a few – are used to produce new PVC, as feed for other
manufacturing processes or as fuel for energy recovery.
Not ideal for energy recovery due to high chlorine content which causing unfavorable pollution
Plastic Name: Low Density Polyethylene LDPE
Plastic Type: type 4
Density: .92 g/cm^3
Monomer Structure:
Polymer Formation: breaking of double bonds
Uses: trays, corrosion-resistant work surfaces, parts that need to be weldable and machinable, six
pack rings, juice/milk cartons, packaging for computer hardware, playground slides, plastic
wraps
Melting Point: 115 C
Other recycling considerations:
Currently not recycled because it is so light that it gets stuck in equipment
Plastic Name: Polypropylene PP
Plastic Type: type 5
Density: .9 g/cm^3
Monomer Structure:
–[CH2-CH(CH3)]n–
Polymer Formation: breaking of double bonds
Uses: flip-top bottles, manufacturing of piping systems, medical/laboratory equipment, food
containers,
Melting Point: 170 C
Other recycling considerations:
36
Plastic Name: Polystyrene PS
Plastic Type: type 6
Density: 1.05 g/cm^3
Monomer Structure:
–[CH2-CH(C6H5)]n–
Polymer Formation: breaking of double bonds
Uses: protective packaging (packing peanuts, CD/DD cases) containers, lids, bottles, trays,
tumblers, disposable cutlery
Melting Point: 240 C
Other recycling considerations:
Plastic Name: other acrylic, polycarbonate (PC), polylactic fibers, nylon (PA), fiberglass
Plastic Type: type 7
Density:
Monomer Structure:
Polymer Formation:
Uses: miscellaneous
Melting Point:
How its made:
Other recycling considerations:
Difficult to recycle, but some could be done by chemolysis (carbonates)
There is such a mixture here that it is hard to know exactly what you're getting. (Maxon)
Appendix B: Process Notes
Grinder/shredder/granulators (something to break into smaller pieces)
Process description: Plastic materials usually need to be cut into smaller sizes in order to allow
further processing and to provide easier packaging, transportation, and distribution of recycled
stock. This cutting presents certain challenges, as many plastics are abrasive to metal blades and
can have wide variation in their hardness, weight, and thickness. Most standard size reduction is
performed by single or multi-shaft shredders, and granulators. Multi-shaft shredders perform
scissor-like cutting with a series of rotating blades that can handle moderately dirty or
contaminated material but are somewhat imprecise in the size of the cuts. Single shaft shredders
perform more of a tearing motion and have slower motors that lengthen blade lifespan. They can
also handle dirty or abrasive material and usually have adjustable or replaceable blades.
Granulators are composed of a rotor attached to blades that rotate within a chamber containing a
grid floor. Their capacity for processing plastic material depends on the speed of the rotor, angle
of the cutting blades, spacing of the grid, and the shape of the rotor. Granulators are usually
sturdy machines, capable of relatively rapid cutting rates, and the presence of the grid allows for
more precise control over the size of cuts. Granulator blades typically need to be replaced
regularly over the course of operations.
Types of plastics involved: all
Washing Equipment
Process description: Paper, glue, sand, and grit are some of the common elements targeted in the
washing process, which can be accomplished using water baths, friction washers, or a washing
line. The washing line applies a continuous hot spray over a stream of plastic material, removing
37
some or all of the labels and dirt attached to the plastic surface. Detergents and disinfecting
agents are often included in this process to improve the level of cleaning.
Types of plastics involved: all. Can be done before or after ground into small pieces
(How Plastic Recycling Equipment Works, 2019)
Float-sink separation
Process description: Typically uses a water bath to separate plastics between those denser and
less dense than water. Other fluids can be used, but this would require another washing
stage. Many plastics, especially those denser than water, have relatively large density ranges that
overlap, making further separation difficult. PE and unfilled PP (PP without talc) will float (float
fraction), and filled PP, PS, PET, PVC, ABS, and other plastics will sink (sink
fraction). Minimum difference in density must be at least 0.2 g/cm3 (Paprec).
The float fraction is sent to a wind sifter where the LDPE and some PP (soft fraction) are
separated from the HDPE and PP (hard fraction) using the difference in mass. The hard fraction
can then be used as a secondary raw material, but the soft fraction is too low in bulk density and
must be run through another regranulation with melt filtration step before being extruded.
The sink fraction can be used right away as a secondary raw material. However, this project
needs to maximize production of value-added products. Therefore, plastics such as PET and
PVC must be separated out. Current float-sink separators can process 4 tons per hour of mixed
plastic (MSS Optical, 2019)
Types of plastics involved: Mixed polyolefins (MPO), solid plastic waste (SPW). PE, PP, PS,
PVC, ABS, PET, etc (all common plastics).
Wind Sifter
Process description: Used to sort the float fraction from float-sink separator. Sorts LDPE from
HDPE. PP is split between both output streams based on its density.
Types of plastics involved: LDPE, HDPE, PP.
X-ray sorting
Process description:
Types of plastics involved: Separating PVC from PET
Selective Dissolution:
Process description: The goal is to sort plastics using solvents. Supercritical fluids (SCFs) are
the best option as they tend to be nontoxic and usable for recycling food grade plastics. A
mixture of plastics is dissolved with the intent of either dissolving all the plastics except one or
dissolving a single type.
Types of plastics involved: Sink fraction from float sink
Chemolysis
• 15,000 tons/yr to be economically feasible (Swedish master’s thesis)
Process description:
Types of plastics involved: only PET
The following notes are from (Aguado, 2007) unless otherwise specified:
38
Methanolysis: pg 37 treatment of PET with methanol at relatively high temperatures (180-280C)
and pressures (20-40atm) to make ethylene glycol and dimethyl terephthalate (DMT)
• Products are separated by crystallization or distillation
• Step 1: heat and melt PET to reaction temperature
• Step 2: contact with methanol
• OR
• PET contacted with superheated methanol vapors
• Recent applications:
o Supercritical methanol at temperature of 300 degrees Celsius and pressure above
80atm; faster PET decomposition compared to used liquid methanol
o Pg 44. Energy requirement of 40-60 MJ/kg of PET
• Typically requires large scale plants to be economically feasible
• Contamination of initial PET waste is a limiting factor
• Depolymerization increases as methanol to PET ratio increases and reaction time
increases (Yang, 2001)
Hydrolysis: pg 38 reacting PET with water to create terephthalic acid (TPA) and ethylene
glycol—carried out under neutral, acidic, or basic conditions
• Need to have excellent purification process to gain TPA, use crystallization with solvents
like acetic acid
• Purification is complex…not very industrialized yet, maybe not even economically
feasible????
Glycolysis: pg33 reaction of PET under pressure and temperatures between 180-240C in excess
glycol (usually ethylene glycol) promoting formation of BHET
• BHET is purified by melt filtration
• Depolymerization is carried out in the presence of transesterification catalysts such as
zinc or lithium acetate
• OR
• EG/PET at 190C (with excess EG at ratio 1/1.3 by weight) in presence of metal acetates;
type of metal acetate affects initial rate of depolymerization; requires purification to separate
green and colorless BHET
• Can be economic with small and medium sized plants
• Oldest and simplest method of PET depolymerization
• Contamination of initial PET waste is not a limiting factor
39
• Contacting PET scrap with ethylene glycol at (453-523K) during 0.5-8hrs to make
bis(hydroxyethyl)terephthalate (BHET) to be repolymerized (Carta, 2003)
• Depolymerization is proportional to the square of EG concentration…EG is a catalyst and
reactant (Carta, 2003)
The following notes are from (Al-Sabagh, 2016) unless otherwise specified:
types of catalysts…
considerations: temperature, pressure, PET/EG ratio, type and amount of catalyst
also, reaction time…if we prolong too long after equilibrium the reaction can reverse
catalysts:
HOMOGENEOUS:
• Metal acetates
o Heavy metals with negative environmental impacts
o Zinc ~ 62.8%
• Mild alkalis
o Sodium carbonate
o Sodium bicarbonate
o Similar yields to metal acetates
• Metal chlorides
o Zinc chloride ~ 73.34% yield
• SEE above
o Catalysts are soluble in ethylene glycol and need distillation to remove them from
the product stream
o Zinc salts do not increase glycolysis rates at temps above 245 degrees Celsius
o Catalysts cannot be recycled and reused
o Side reactions
o Product purity is a problem
HETEROGENEOUS:
• Zeolites
o Similar yield to homogeneous catalysts
• Metal oxides on silica supports
• Graphene oxide manganese nanocomposite
• Solid catalysts
IONIC LIQUIDS:
• Salt in a liquid state with a melting point lower than 100C
• Purification of products is simpler than conventional catalysts
• 100% conversion 180C with 1-butyl-3-methyl-imidazolium
• Bmim OAc can be reused up to 6 times
(Damiana)
Pyrolysis - Cracking
Process description: The pyrolysis of waste plastics involves the thermal decomposition in the
absence of oxygen / air. During the pyrolysis, the polymer materials are heated to high
temperatures and thus, their macromolecules are broken into smaller molecules, resulting in the
formation of a wide range hydrocarbons. The products obtained from the pyrolysis can be
40
divided into non-condensable gas fraction, liquid fraction (consisting of paraffins,
olefins, naphthenes and aromatics) and solid waste. From the liquid fraction can be recovered
hydrocarbons in the gasoline range (C4-C12), diesel (C12-C23), kerosene (C10-C18) and motor
oil (C23-C40)
Types of plastics involved:
Still relatively new idea. Found a paper that used a batch reactor with LDPE and HDPE with a
HZSM-5 zeolite catalyst to produce the following:
I would imagine other types of plastics that are made of hydrocarbons would work as well.
Catalyst might change, but need more research
Also, catalytic cracking (catalytic pyrolysis) can have conversion as high as 100% for plastic
waste and oil yields between 86 and 92 %. Heterogeneous solutions often used due to lower cost
and high availability. Three types of catalysts are used: zeolites, fluid catalytic catalysts, and
silica alumina catalysts.
Fluid Catalytic Cracking (FCC): secondary conversion in oil refinery and provides most of the
world's gasoline. Figure below shows process. Biggest problem is catalyst roughly last 1 month
and all catalyst needs to be removed each time.
Reactor Design -
(Waste Plastic Pyrolysis Plant, 2019)
(“Continuous Thermal Decomposition Plant (TDP-2-800): Thermal Decomposition Plant”).
Continuous, 20-40 ton per day speed, built in heat exchanger, vents ect
(“Waste Plastics Pyrolysis Plant”)
And the winner is: http://www.plastic2oil.com/site/advantage
• The conversion ratio for waste plastic into fuel averages 86%.
• Approximately 1 gallon of fuel is extracted from 8.3 lbs. of plastic.
• The processor uses its own off-gases as fuel (approximately 10-12% of process output);
minimal energy is required to run the machine.
• Approximately 2-4% of the resulting product is Petcoke (Carbon Black), a high BTU
fuel.
• Emissions are lower than a natural gas furnace of similar size, and the quality of the
emissions improve with increased feed rates.
• Results from the final stack test performed by Conestoga-Rivers & Associates confirm
that the processor emissions are well within the limits allowable under a NYSDEC air
permit.
• The process operates at atmospheric pressure, and is not susceptible to pinhole leaks
and/or other problems with pressure and vacuum-based system.
• The reusable catalyst is produced economically.
• The fuel produced is refined and separated without the high cost of a distillation tower.
41
Separation methods for pyrolysis
(Qian, 2019). (Maxon)
Appendix C: Methanolysis Mass Balances
Attached excel spreadsheet with analytical mass balance and Aspen simulation mass balance
named: Methanolysis Mass Balances
This excel file contains several versions of the mass balance. The first is the analytical mass
balance based on assumed product purities as shown in Table 5. The analytical mass balance is
based on the actual reaction stoichiometry of the methanolysis reaction (1 mole of EG and 1
mole of DMT are produced from 1 PET monomer mole and 1 methanol mole). The second mass
balance over the whole process is based on the Aspen RM-1 reaction conversions which are
modelled using different stoichiometry. This is because Aspen does not model polymers (or
include plastic polymers in the database since the chain lengths will vary), so ethylene
terephthalate was used to model the PET monomer instead. The stoichiometry of this reaction is
shown in the Mass Balance (Aspen) tab. Mass Balance (Actual) was used for economic analysis.
(Damiana)
Appendix D: Detailed Pyrolysis Emissions
Table 161 below summarizes estimates for air and water emissions. Primary air emissions from
the P2O process include particulate matter, carbon dioxide, nitrogen oxides, hydrocarbons and
VOC’s; however, JBI is not required to monitor emissions or install emissions control
technologies. In terms of emissions, converting one ton of plastic using JBI’s P2O process
yields approximately 0.29 pounds of carbon equivalents. The process also reports 2.41 pounds of
NOx emitted for every ton of waste plastic. JBI reports that the atmospheric emissions are less
than a natural gas furnace. Water is used for gas cooling, and wastewater from this step is
reused, but no water effluent is generated (RTI International, 2012).
Table 16: Detailed pyrolysis emissions
42
(Maxon)
Appendix E: Total Cost Analysis Excel Spreadsheet
Attached excel spreadsheet submitted with this report named: Total Cost Analysis
Appendix F: Aspen Plus Files
Attached Aspen Plus file submitted with this report named: Pyrolysis System (Maxon) and
Methanolysis Simulation (overall process simulation) and Methanolysis Distillation (basis for
distillation tower sizing and utility) (Damiana)
Appendix G: Complete HAZOP Analysis
Equipme
nt or
Section
Parameter;
Possible
Deviation
Deviation
Cause
Deviation
Consequences
Additional
Implications
Process
Indicatio
ns
Notes & Questions
Plastic
Prep-
Anders
Prewasher No flow of water 1. Leak
2. Faulty pump
1. Water is not
contained in
the unit
2. Water is not
being used in
the unit
1. Spills present
potential hazard
for operators
2. Contaminants
remain in the
stream
1./2. Flow
sensor
1. Can we used
recycled water from
our plant, or does
this need to be new
water?
2. If so, how much
of it can be
recycled?
Friction
Washer
No flow of water 1. Leak
2. Faulty pump
1. Water spills
from the unit
2. Water is not
being used in
the unit
1. Spills present
potentially
hazardous
conditions for
operators
2. Contaminants
remain in the
stream
1./2. Flow
sensor
1. Is there a
backup?
2. Can this use
recycled water?
3. Is there a purge
stream?
Friction
Washer
Purity of Plastics 1. Motor
failure
1. The washer
is no longer
rotating
1. Friction is not
being generated;
plastics are not
being washed
Alarm 1. How do we
check the plastics
purity?
1. How do we deal
with backups in our
plant if one unit is
shut down?
Shredder No power 1. The unit is
offline
1. Blades stop 1. Nothing is
shredded
2. Potential
danger for
operators
bringing the
1. Flow
meter
1. What safety
precautions are
needed?
43
shredder back
online
Dryer Rotor failure 1. Loss of
power, motor
failure
1. Uneven
drying
1. Water is
introduced to the
following units
1. Flow
meter
1. Is there a
backup?
2. How bad is it if
water goes into the
other units?
Dryer Temperature
1.More
2.Less
1. Heater
output is too
high
2. Heater
output is too
low
1. Plastics
being to melt
2. Plastics are
not dry
1. Plastic buildup
fouls the
shredders blades,
following units
2. Water is
introduced to the
following units
1./2.
Temperatu
re sensor
1. What does
maintenance look
like for this unit?
(specifically
regarding fouling)
Granulator No power 1. Unit failure 1. PVC is not
being
granulated
1. The product
cannot be sold as
intended
2. Potential
danger for
operators during
start up due to
blades
Alarm 1. System will need
storage for
granulated material
Sorting -
Nunzio
IR sorter Utility failure
1. Scanner
failure,
power loss
1. Improper
sorting; no
sorting
1. Some target
plastics not
recycled
2. Waste stream
overflow
1. Flow
sensor
in IR
sorter
1. If storage tanks
are used to
collect material
before sending
to the reactor,
will a level
sensor be
adequate as a
process
indicator?
2. Storage and/or
baling needed
for waste
stream.
Scanning;
misidentification
1. Error in
identificati
on
algorithm
1. Improper
sorting
1. Process
contaminatio
n; pyrolysis
catalyst
poisoning;
toxic gaseous
product
release;
1. IR
sorter
flow
sensor
1. Storage vessels
should be used
to prevent
missorted
material from
immediately
entering the
wrong reactor.
44
pyrolysis of
PET
Pyrolysis
-Maxon
Reactor
(R1)
Temperature
More
Less
1. R1 heater
malfunction;
temperature
sensor
measures
too low
2. R1 cooling
system
failure
3. External fire
4. R1 heater
failure;
temperature
sensor
measures
too high;
heater unit
fails
1. Reactor
failure
2. See event 1
3. See event 1
4. Incomplete
reaction;
products
outside desired
range
1. Damage to
reactor and
surrounding
equipment
2. See event 1
3. See event 1
4. See event
1.
Temperatu
re sensor
in R1
2. See 1
3. See 1
4. See 1
1. Can we have
multiple sensors?
2. What are our
backup cooling
systems?
3. What could
cause an external
fire? What are our
fire protection
capabilities?
4. See 1; Do we
have a backup
heating unit?
Pressure
More
Less
1. Discharge
blockage
2. Valve closed
downstream
3. Failed
pressure relief
valve
4. R1 leak
1. Reactor
failure;
2. See event 1
3. See event 1
4. See event 4
1. Pump
cavitation
downstream
2. Pipe burst,
reagent release
3. Reagent
release; damage
to other
equipment
4. See event 3
1.
Pressure
sensor in
R1
2. See 1
3. See 1
4. See 1
1. What are our
procedures to
quickly remove
blocks?
2. What type of
valve is this? Can
we override the
closer using
computer systems
or does it need to be
manual?
3. What are our
backup relief
valves? How
quickly can we
release pressure?
4. What procedures
do we have for
clean-up and
fixing?
Flow
45
More
Less
No
1. Sorter
malfunction
resulting in
too high of
input
2. Regenerator
valve stuck
open
3. Input
variance
4. Sorter
failure
5. Regenerator
valve shut
6. Leak
7. Input
variance
8. Pipe rupture
9. Inlet
blockage
1. Incomplete
reaction;
products
outside desired
range
2. See event 1
3. See event 1
4. See event 1
5. See event 1
6. Reagent
released
7. See event 1
8. See event 6
9. Pump
cavitation
downstream
1. Damage to
condensers; pipe
burst, reagent
released
2. See event 1
3. Pressure stress
on equipment
4. Pump
cavitation
downstream
5. Regenerator
pressure build
up; failure
6. Fire
7.
8. Pump
cavitation
downstream; fire
9. Pipe burst;
reagent released
1.
Flowmeter
at inlet
2.
Flowmeter
at
discharge
3. See 1
4. See 1
5. See 2
6. Either
flowmeter
7. See 1
8. Either
flowmeter
9. See 1
1. Do we have a
purge stream?
Would it be
necessary to add
one?
2. How can we
change this valve?
Can we easily
change the air input
to account for this
issue?
3. What pressure
variance is our
equipment rated
for?
4. How quickly can
we turn off the
pumps/system?
5. See 2
6. What procedures
do we have for
clean-up and
fixing?
7. What variance
can our equipment
handle?
8. See 4; See 6;
9. What are our
procedures to
quickly remove
blocks?
Composition
Other than
1. Improper
sorting
1. Poisoning
of catalyst
2. Thermal
decomposit
ion of
nontarget
plastics
1. Toxic
gaseous
products
produced
2. Contaminatio
n of product
3. Termination
of reaction
1. Qualit
y
control
system
Use storage tanks to
prevent missorted
material from
entering the reactor.
Condenser
s [Cond1,
Cond2,
and
Cond3]
Flow
More
1. Sorter
malfunction
resulting in too
high of input
1. Lack of heat
removed,
products
outside of
desired range
1. Damage to
following
equipment;
increase
pressure; pipe
1. Flow
meter
1. How quickly can
we turn adjust the
flow rate of the
system?
46
Less
No
2. Leak
3. Sorter
failure
4. Rupture
2. Product
released
3. See event 1
4. Product
released
burst; product
released
2. External fire
3. Pump
cavitation
4. See event 3
2. See 1
3. See 1
4. See 1
2. What are our
clean-up
procedures?
3. How large is the
leak? How can
we fix it?
4. What is the
fastest way to
detect sorter
failure?
5. See 2
Pressure
More
1. Fouling
2. Increased
flow
1. Inefficient
heat transfer
2. see event 1
1. Rupture;
inadequate heat
transfer
2. See event 1
1.
Pressure
gauge
2. See 1
1. How can we
measure fouling?
What are our
cleaning
procedures?
2. Are there
pressure relief
valves? Should
there be?
Separator
[Sep1,
Sep2,
Sep3]
Pressure
More
1. Condenser
failure
2. Discharge
blocked
1. Vessel
rupture
2. See event 1
1. Products
released;
external fire;
products outside
desired specs
2. Pump
cavitation
downstream; see
event 1
1.
Pressure
gauge
2. Flow
meter at
discharge
1. Do the separators
have pressure relief
valves?
2. What other
equipment is in
danger of damage if
it ruptures?
3. How quickly can
blockages be
cleared? What is
the protocol?
Temperature
More
Less
1. Condenser
failure
2. Condenser
malfunctio
n
1. Vessel
rupture
2. Products
outside desired
range
1. Products
released;
external fire;
products outside
desired specs
2. Overflow of
collection tanks
1.
Temperatu
re gauge
2. See 1;
level
meter
1. What equipment
is located nearby?
What are our clean-
up procedures?
2. What are our
backups if
condensers
malfunction? What
are their
47
maintenance
schedules?
Methanoly
sis -
Damiana
Reactor
(RM-1)
Level
More
Less
1. Unload too
much
reactant
into reactor
vessel
2. Reactor
leak
3. Distillation
column
failure;
failure to
return
methanol
supply to
reactor
Reactor
overfills
Reactor
components
released
No reaction
occurs; thermal
decomposition
of PET ensues
Reagents
released via
pressure valve
Fire possible
Toxic gaseous
products
produced
Pressure
relief
valve,
level
controller
Level
controller
Flow
meter
from
distillation
column
What level
indicators are
included with the
tank?
See Event 1.
How is the recycle
stream
monitored/measure
d?
Composition
Other than
As well as
4. Incorrect
inlet plastic
stream;
sorter
malfunctio
n
5. Reagent
other than
methanol
unloaded
6. Methanol
impurities
in non-
recycle
stream
(MET)
Possible
reaction
Possible
reaction
Overpressure if
volatile
Possible fire if
materials
incompatible
with reaction
reactants or
products
Reactor rupture
Combustion
possible; reactor
rupture
Possible reactor
rupture
Quality
control
system
Quality
control
system.
Quality
control
system
How is plastic feed
purity monitored?
Consider testing the
unloaded feed.
What impurities are
possible in
methanol?
48
Pressure
More
Less
7. Tank
overfills
8. Higher
temperatur
e
9. Heating
unit failure
See Event 1
Pressure
released via
relief valve
Solid material
pumped to
downstream
liquid unit
operations
Pressure relief
valve failure and
reactor rupture
Reagent released
Pipe blockage or
burst
Reagents
released to
atmosphere
Damage of
downstream
equipment
Pressure
relief
valve/
temperatur
e
controller
Temperatu
re
controller/
pressure
relief
valve.
Temperatu
re
controller/
flow
meter
controller
What are the
pressure limits of
the reactor?
How will the
reaction be
monitored? How
will the product
conversion be
determined?
Temperature
More
Less
10. Temperatur
e inside
tank is
higher than
design
specificatio
ns
11. Internal/ext
ernal fire
12. Low tank
pressure
Gaseous
components
released to
atmosphere via
relief valve
Reactor fails
See Event 9
Tank rupture if
relief valve fails
Combustion of
tank
components,
toxic gas release
Temperatu
re
controller/
pressure
relief
valve
What are the
temperature limits
of the reactor?
What can cause
combustion of the
feed materials?
What are the
pressure limits of
the tank?
Distillatio
n Column
1 (DM-1)
Flow
More
Less
13. Unload too
quickly
Column
weeping/dumpi
ng
Change in
product quality
Temperature
decreases
Flow
meter at
inlet
What flow rates are
the distillation
column designed to
separate?
49
No
14. Pipe
blockage
before
DM-1 inlet
15. Pipe leak
before
DM-1
16. Column
leak
17. See Less
Column dries
out
Column dries
out
Reagent
released
Pipe burst and
reagent released
Pipe burst and
reagent released
Flow
meter at
inlet
Flow
meter at
inlet
Flow
meters at
inlet and
exit
How is product
quality from RM-1
monitored?
What are the checks
in place for leaks in
the piping system?
How will gaseous
leaks in the system
be monitored?
Composition
Other than
As well as
18. Reactor
failure
19. Nitrogen
purge flow
to column
contaminat
ed
See events 2-6,
9, 11
Potential fire
from
combustion
Quality
control
system
What contaminants
are possible that
may lead to
combustion? Are
there other leaks in
the system that lead
to contamination?
Pressure
More
Less
20. Flooding
21. Reboiler
failure
Liquid reagent
forced out top
of column
Weeping/dump
ing of trays
Change in
product quality
Change in
product quality
Flow
controller
Temperatu
re
controller/
flow
controller
What are the
pressure limits of
the column?
Temperature
More
22. Condenser
failure
23. Inlet feed
temperatur
e higher
Potential fire
Flooding
Distillate
composition
changes
Potential fire if
vapor contact
with combustible
material
Temperatu
re
controller/
flow
controller
Flow
controller/
What are the
temperature limits
of the column?
50
Less
than
normal
24. Reboiler
failure
Weeping/dump
ing of trays
Change in
product quality
temperatur
e
transmitter
Temperatu
re
transmitter
/ flow
controller
Distillatio
n Column
2 (DM-2)
Flow
More
Less
No
25. Unload too
quickly
26. Pipe
blockage
27. Pipe leak
28. Column
leak
29. See Less
Column
weeping/dumpi
ng
Column dries
out
Column dries
out
Reagent
released
Change in
product quality
Temperature
decreases
Pipe burst and
reagent released
Pipe burst and
reagent released
Flow
meter at
inlet
Flow
meter at
inlet
Flow
meter at
inlet
Flow
meters at
inlet and
exit
What flow rates are
the distillation
column designed to
separate?
How is product
quality from RM-1
monitored?
What are the checks
in place for leaks in
the piping system?
How will gaseous
leaks in the system
be monitored?
Composition
Other than
As well as
30. DM-1
failure
31. Nitrogen
flow to
column
contaminat
ed
See Events 13-
23
Potential fire
from
combustion
Quality
control
system
How can the
nitrogen purge
stream be
contaminated?
Pressure
More
32. Flooding
Liquid reagent
forced out top
of column
Vapor released
Flow
controller
What are the
pressure limits of
the column?
51
Less 33. Reboiler
failure
Weeping/dump
ing of trays
Temperatu
re
controller/
flow
controller
Temperature
More
Less
34. Condenser
failure
35. Inlet feed
temperatur
e higher
than
normal
36. Reboiler
failure
Potential fire
Column
flooding
Weeping/dump
ing of trays
Potential fire if
vapor contact
with combustible
material
Temperatu
re
controller/
flow
controller
Flow
controller/
temperatur
e
transmitter
Temperatu
re
transmitter
/ flow
controller
What are the
temperature limits
of the column?
Appendix H: SDS files
Attached with submission of the report is a folder with the necessary SDS for this process.
Appendix I: Equipment Sizing
Attached excel spreadsheets submitted with this report named: Pyrolysis Equipment Sizing
(Maxon) and Methanolysis Equipment and Products (Damiana)
Appendix J: Environmental Impact Calculations
Attached excel spreadsheet submitted with this report named: Environmental Impact
Calculations (Maxon)
