Office of Research and DevelopmentNational Risk Management Research Laboratory, Land and Materials Management Division
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Gerardo J. Ruiz-Mercado (1), Ana Carvalho (2), and Heriberto Cabezas (1)
(1) National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH, USA(2) CEG-IST, Instituto Superior Tecnico, Universidade de Lisboa, Lisboa, Portugal
Using Green Chemistry and Engineering Principles to Design, Assess, and Retrofit Chemical Processes for Sustainability
7th International
Congress on
Sustainability Science &
Engineering
Cincinnati, OH, USA
Disclaimer
The views expressed in this presentation are
those of the author and do not necessarily
represent the views or policies of the U.S.
Environmental Protection Agency.
1
Outline
• Sustainability: Conceptual
• Process Design
• Sustainable Process Screening: WAR Algorithm
• Sustainable Process Assessment: GREENSCOPE
• Sustainable Process Retrofit: SustainPro
• Sustainable Process Design: Bringing it Together
2
Sustainability:
Conceptual
3
0
1000
2000
3000
4000
5000
6000
7000
8000
-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000
Hu
man
Po
pu
lati
on
Year
Historical World Population(https://en.wikipedia.org/wiki/World_population)
4
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
-4500 -3500 -2500 -1500 -500 500 1500 2500
Real
GW
P
Year
Real Gross World Product(https://en.wikipedia.org/wiki/Gross_world_product)
($US billions, 1990 intl $US)
5
World Ecological Footprint &
World Biocapacity
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
1961 1965 1970 1975 1980 1985 1990 1995 2000 2005 2007
Foo
tpri
nt
& B
ioca
pac
ity
(he
ctar
es)
Year
~1977
6
Total Ecological Footprint
Total Biocapacity
Source: National Footprint Accounts 2010 edition
www.footprintnetwork.org
Courtesy of M. Hopton, U.S. EPA
How does the biophysical
world work?(Mostly Closed to Mass & Open to Energy)
Earth:
life,
economy,
society,
technology,
etc.
Sun
Light
Energy
Dissipation
to Space
7
Process Design
8
Processes/Industrial
Manufacturing
9
Process SalesRaw
Materials
Capital
Energy
Products
Customers
ProfitsWaste
Mass
Waste
Energy
Sustainable Processes
10
IT HAS TO BE SYSTEMATIC SO THAT GOOD
OPTIONS DONOT GET OVERLOOKED!
1. There is a hierarchical scheme for sustainable
process design:
a. WAR Algorithm for initial screening and
analysis of new and existing designs.
b. GREENSCOPE for detailed process
analysis.
2. For established process designs, SustainPro
provides an effective algorithm for retrofitting
to make processes more sustainable.
Sustainable Process
Design: WAR Algorithm
11
Potential Environmental
Impact (I or PEI)
12
Chemical
Process
İout(w)
İgen
𝜓𝑙 = 𝛼𝑚𝜓𝑙𝑚
𝑚
𝐼 𝑘(𝑖)=
𝑑𝐼𝑘(𝑖)
𝑑𝑡=
𝑑𝑀𝑘(𝑖)
𝑑𝑡 𝑥𝑘𝑙𝜓𝑙
𝑙
Potential Environmental
Impact Balances
13
𝑑𝐼𝑆𝑦𝑠𝑡𝑒𝑚
𝑑𝑡=
𝑑𝐼𝑘(𝑓)
𝑑𝑡𝑘=𝑓
− 𝑑𝐼𝑘
(𝑝)
𝑑𝑡𝑘=𝑝
− 𝑑𝐼𝑘
(𝑤)
𝑑𝑡𝑘=𝑤
+𝑑𝐼𝑔𝑒𝑛
𝑑𝑡
𝑑𝐼𝑔𝑒𝑛
𝑑𝑡=
𝑑𝐼𝑘(𝑝)
𝑑𝑡𝑘=𝑝
+ 𝑑𝐼𝑘
(𝑤)
𝑑𝑡𝑘=𝑤
− 𝑑𝐼𝑘
(𝑓)
𝑑𝑡𝑘=𝑓
General Expression:
Steady State:
Design Criteria
14
𝑑𝐼𝑔𝑒𝑛
𝑑𝑡≤ 0
Either Consume PEI or Minimize PEI Generation:
Minimize the Output of PEI:
𝑑𝐼𝑘
(𝑝)
𝑑𝑡𝑘=𝑝
+ 𝑑𝐼𝑘
(𝑤)
𝑑𝑡𝑘=𝑤
≥ 0
Sustainable Process
Design: GREENSCOPE
15
Chemical Process Indicators
16
• Triple dimensions of sustainable development
–Environment, Society, Economy
–Corporate level indicators
–Assessment at corporate level
Economy
Society Environment
Sustainable
development
Eco-efficiency Socio- economic
Socio-ecology
Rele
ases
E
col. g
oods &
serv
ices
Revenues
Econ.
goods &
serv
ices
Releases
Ecol. goods & services
• Four areas for promoting & informing sustainability
• Environmental, Efficiency, Economics, Energy (4E’s)
• Decision-making at process design level
• Taxonomy of chemical process indicators for use in process design
GREENSCOPE Indicators
17
Environmental (66)
•Specifications of
process input material
(e.g., hazardous)
•Operating conditions
and process operation
failures (health and
safety hazards)
•Impact of components
utilized in the system
•Potential impact of
releases
•100% sust., best target,
no pollutants release, &
no hazardous material
use or generation
Efficiency (26)
•Quantities of inputs
required/product or a
specific process task
(e.g., separation)
•Mass transfer
operations, energy
demand, equipment size,
costs, raw materials,
releases
•Connect input/output
with product,
intermediate or
operation unit
•The reference states are
defined as mass fractions
0 x 1
Economic (33)
•A sustainable
economic outcome
must be achieved
•Based on profitability
criteria for projects
(process, operating
unit), may or may not
account for the time
value of money
•Some cost criteria
Indicators: capital &
manufacturing costs;
Input costs: raw
material cost; Output
costs: waste treatment
cost
Energy (14)
•Different
thermodynamic
properties used to
obtain energetic
sustainability scores
•Energy (caloric); exergy
(available); emergy
(embodied)
•Zero energy
consumption per unit of
product trend can be
best target
•Most of the worst cases
depend on the particular
process or process
equipment
GREENSCOPE
Sustainability Framework
18
Identification and selection of two reference states for •
each sustainability indicator:
Best target: • 100% of sustainability
Worst• -case: 0% of sustainability
Two scenarios for normalizing the indicators on a realistic •
measurement scale
Dimensionless scale for evaluating current process or •
tracking modifications/designs of new (part of a) process
Actual-Worst
% Sustainabilty Score = 100%Best-Worst
Sustainability Assessment &
Design: GREENSCOPE Tool
19
Classification lists, energy conversion factors,
potency factors
Physicochemical, thermodynamic, and
toxicological properties
Equipment, raw material, utility, and product costs, annual salary, land cost
GREENSCOPE
Energy (e.g., steam) Products
ReleasesRaw material (e.g., oil)
CHEMCAD Simulation
Energy & massEquipment
Operating conditionsProduct & releases
Experimental dataPredicted dataProcess data
Literature dataAssumptions
Tools/Simulation
All indicator results Satisfied?
Potential sustainable
process
YES
NO
Process designDecision-making
Experimental work Process modeling & optimization
New process design specifications
GRNS.xls Template
Efficiency Indicator Results
20
Indicator Description Sust. (%)
2. AEi Atom economy 5.8
7. MIv
Value mass
intensity0
15. MRPMaterial recovery parameter
0
17. pROIM
Physical return on
investment99.4
23. Vwater,
tot.
Total water
consumption100
Environmental Indicator Results
21
Indicator Description Sust. (%)
1. Nhaz. mat.
Number of hazardous
materials input75
6. HHirritation
Health hazard,
irritation factor68.5
10. SHreac/dec I
Safety hazard, reaction
/ decomposition I88.3
22. EHbioacc.
Environmental hazard,
bioaccumulation (the
food chain or in soil)
89.3
43. EPEutrophication
potential100
Energy Indicator Results
22
Indicator Description Sust. (%)
2. RSEI
Specific energy
intensity98.9
6. E
Resource-energy
efficiency77.0
8. BFE
Breeding-energy
factor100.0
10. Extotal
Exergy
consumption0.0
14. BFEx
Breeding-exergy
factor36.1
Economic Indicator Results
23
Indicator Description Sust. (%)
1. NPV Net present value 45.9
8. PBP Payback Period 92.0
19. COM Manufacturing cost 68.0
23. CE, spec. Specific energy costs 63.1
33. Cpur. air
fract.
Fractional costs of
purifying air0.0
Process Retrofit:
SustainPro
24
Process Retrofit
25
Retrofit design has been defined by Guinand (2001) as
follows: “Process retrofitting is the redesign of an operating
chemical process to find new configuration and operating
parameters that will adapt the plant to changing conditions
to maintain its optimal performance.”
1- Identify process bottlenecks
2-Select the most relevant bottlenecks for
improvements
3- Suggest new design alternatives -eliminate
the bottlenecks
4- Assess and select new design
alternatives
Retrofit Generic Methodology
SustainPro- Retrofit Tool
26
Collect Data
STEP 1Simulators
Flowsheet Decomposition• OP and CP
STEP 2
Equipment flowsheet into operational flowdiagram
STEP 1.A
Flowsheet Decomposition• AP
STEP 2
Simulators Plant Data
Calculate Indicators
STEP 3
3.1 Mass/Energy indicators3.2 Sustainability Metrics
3.3 Safety Indices
Calculate Indicators
STEP 3
3.4 Operational Indicators3.5 Compound indicators
Indicator Sensitivity Analysis (ISA)
STEP 4
Sensitivity analysis operational parameters
STEP 5
Generate/Evaluate new design alternatives
STEP 6
Properties
WAR
Solvent Separation
Properties
Continuous & Batch
Batch
Tools
SustainPro
CAPEC Database
ICAS - ProPred
ICAS – WAR algorithm
Super Pro Designer
Gproms
Aspen Tech
Pro II
ICAS 11
HYSYS
ICAS - ProCamd
Thermodynamic insights
Lable
SustainPro- Retrofit Tool.
27
Continuous Process Batch Process
Closed-path Open-path Accumulation-path
Step 1- Data Collection
Step 2- Flowsheet Decomposition
OR
Simulators
EA EB EC1 2 3 4
5
OP1 OP2 OP3
1 2
3
4 5
6
78 9
10
SustainPro- Retrofit Tool:
Indicators
28
Indicator Description Definition
MVA Material Value Added MVA = MT*(Psale-Pcost)
EWC Energy & Waste Cost EWC = E PE Mi θi/(Σi Mi θi)
TVA Total Value Added TVA = MVA - EWC
RQ Reaction Quality RQ = RX θR/ (Σp Mp)
AF Accumulation Factor AF = Mi-cycle /(Σk-cycle Mk-cycle)
REF Reusable Energy Factor REF = Eused-cycle/ Eexit-cycle
DC Demand Cost DC = PutilityEopen-path
TDC Total Demand Cost TDC = Σ DCk
Step 3- Indicators Calculation
SustainPro- Retrofit
Tool: Algorithm
29
IndicatorsVariables (VI)
VI,1
VI,2
…
VI,N
ObjectiveFunction (VOF)
VOF,1
VOF,2
…
VOF,N
Indicators (I)
I1
I2
…
IN
Common Variables
•Sensitive
•Large Amount
Min Max Score
Vmin Vmin + Inc 1
Vmin + Inc Vmin + 2Inc 2
Vmin + 2Inc Vmin + 3Inc 3
Vmin + 3Inc Vmin + 4Inc 4
Vmin + 4Inc Vmax 5
Scores
EWC, REF, TDC
AF, DC
High PositiveValues
MVA, TVA
RQ
High NegativeValues
HIGHEST SCORES ARE THE TARGETS
Step 4- ISA Algorithm
SustainPro- Retrofit Tool:
Alternatives
30
Target Indicators (TI)
OP1
OP2
…
OPN
Variation5, 10, 15%
Variation5, 10, 15%
Variation5, 10, 15%
Variation5, 10, 15%
ImprovementTI X%
ImprovementTI X%
ImprovementTI X%
ImprovementTI X%
Purge
Improve Separation
Insert New Separation
Increase Conversion
New Solvent
Increase Conversion
Highest Improveme
nt
Recycle
Separation
Inc Conversion
Separation
Source
Separation
Reactor
Change
Insert New
Improve
Separation
Reactor
CP Flowrate
OP Flowrate Raw Material
Product
Inert
Sub-Product
Solvent
Reverse Approach
Thermodynamic Insights
ICAS
Step 5, 6- SA and Generation of
alternatives
Sustainable
Processes: Bringing
It All Together
31
Some Final Thoughts
• There is a hierarchical scheme for sustainable
process design of new designs:
• WAR Algorithm for initial screening analysis.
• GREENSCOPE for detailed process analysis.
• For established process designs, SustainPro
provides an effective algorithm for retrofitting
to make processes more sustainable.
• However, these tools do not and can not
substitute for the skill of the engineer. A fine
hammer is wonderful in the hands of a skilled
carpenter but useless in unskilled hands.32