Date post: | 16-Apr-2017 |
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Introduction: Problem
Recognition of Problem
“This year, for the first time since before the Ice Age, CO2 will not fall below the 400 ppm mark.” -NOAA (2016)
Algae could be used to sequester carbon
Unless made into a product with a long useful lifespan it will decay and re-release the CO2
http://www.esrl.noaa.gov/gmd/ccgg/trends/full.html
Introduction: Goals
Biological- Design a CSTR capable of producing enough algae for a positive revenue in
full scale implementation - Improve bleaching processes through chlorophyll-related options
Structural - Create a paper product that is as strong as store bought wood pulp paper
Mechanical - design a simplified paper making process utilizing the benefits of algae-based
pulp
Introduction: Constraints
Skills - Lack of paper making knowledge
Budgetary - Algal paper production must be comparable in price to similar wood pulp based papers
Space - Can only keep a limited amount of algae for testing at a given time
Logistics - Lab scale tests and procedures are very different from industrial application
Time - Algae growth rate and seasonal weather limits algal biomass available for testing
Introduction: Considerations
Ethical - North Charleston’s Kapstone plant uses chemical pulping which must be heavily treated before being released into the Cooper River.
Safety - Bioaccumulation of toxins could occur in marine life living in or near the effluent flows of paper mills if not treated properly.
Ecological - Inappropriate handling of CSTR effluent could release excess nutrients into the ecosystem. http://www.kapstonepaper.com/location/
charleston-sc/
Introduction: Questions
User- Will traditional pens and pencils write legibly on Algal paper?
- Is the algal paper as durable as comparable traditional papers?
- Will the paper last as long as traditional papers?
Client- What is required to grow algae for paper making?- Can algal pulp be processed using similar equipment to traditional pulp- Can wood and algae pulp be mixed?
Designer- What type of paper is desired by the client (loose leaf, card stock, etc)?- What will be the required strength of the pressed paper?- What type of algae will be used?
Identifying the Algae
Scientific Name: Pithophora oedogonia
Common Name: Cotton-ball Algae/Horsehair Algae
Steps in Design
The final process design based on our preliminary lab data is broken into six major unit operations:
Culture
Drying
Blending
Screening
Pressing
Final Drying
Sourcing Algae
Two options for obtaining algae were explored
Harvest from natural environments
Raised many problems regarding cleaning the algae which translated into the final product
Growth from a culture in a CSTR
Proved much more logical as it removed cleaning difficulties and the Pithophora proved to grow well
Harvesting Algae
Algae was removed from a natural environment
Led to many difficulties in cleaning and keeping the samples alive
Snails, bacteria, and other contaminates soiled multiple harvests
Would be a practical approach if a feasible method of cleaning harvest crop could be developed without damaging the algae
Algae Culture: CSTR with Recycle
Grown in a 2 L CSTR using BG-11 Media to support growth
Flow rate: 1.76mL/s = 6.35L/hr for 4 minutes a day
Time: 11 days
Inoculation Weight: 2g
Final Weight: 3.33g
● Cell Retention Time
● Specific Growth Rate (SS Mass Balance)
● Monod
Governing Equations: CSTR with Recycle
● θ= Cell retention time (hr) ● V= Volume (L)● Qw= Harvest flow rate (L/hr)● XB= Biomass Concentration● μ= Specific growth rate (hr-1)● μm= maximum specific growth rate(hr-1)● b= decay constant (hr-1)● Ss= Soluble substrate concentration (g/L) ● Ks= Half-saturation Constant (g/L)
Bleaching Alternative: Ultraviolet Light
Day 1 Day 3 Day 4
Bleaching: Other Alternatives
Ultra Violet light seems to be the best and least intrusive option
Requires significant time investment and does not completely whiten paper
Repetitive drying and re-soaking of algae to wash out chlorophyll
Will be energy intensive
Chemical Bleaching is another option to explore as it will most likely be the most successful at completely removing all color
Effluent wastewater will have to be treated
Preliminary data: Convection DryerPreliminary Trial:
Oven dried at 68 over 4 days℃Algae was successfully dried with a
brown border
Trial 1:Oven was set to 103 ℃Algae was weighed every 30
minutes for 5.5 hours
Drying occurred at 0.85 g/min
Lab Scale Vacuum Shelf Dryer
Water at 78 C circulated through tray
Water at 25 C circulated through condenser
Vacuum pump at
Drying occurred at 0.13 g/min
Governing Equations: Drying
Fouier’s law of heat conduction
Preliminary data: Pulping dried and undried
Undried
Blends very quickly and easily
Cells do not rupture or shorten
Color stays very green
Dried
Must rehydrate for easy pulping
Cells rupture and shorten
Color fades over time
Preliminary data: Pulping Dried and Undried
Undried Dried
Preliminary data: Pulping
Proctor Silex 59735 immersion blender
Tested dried and undried samples
Fiber lengths of pulped paper averaged 6.45 mm.
http://www.paperonweb.com/pulppro.htm
Governing Equations: Pulping
Reynolds Number
Power in an unbaffled tank
Limiting Vortexing Pbaffled = P⅙ unbaffled
Power in a baffled tank P = kρN3D5
http://mimoza.marmara.edu.tr/~bilge.alpaslan/enve301/Lectures/Chp_6.pdf
Forming Handsheets
Based on TAPPI standards T 218 sp-11
Utilized rehydrated dried algae from drying tests
Proctor Silex 59735 immersion blender was used for pulping
Forming Handsheets
100 mm diameter Büchner funnel
was used to strain pulp
Pressed between granite slabs
Allowed to air dry overnight
Achieved finished test basis weight
of 127 g/m2
Paper Strength
Paper strength in industry is genuinely described by the break length and tensile index of
the paper
Calculated based on the tensile strength of the paper and the basis weight
These values are important in the paper production process as they are indicative of fiber
strength, fiber bonding, fiber length, and also the pulp materials ability to survive in the
heavy duty machines that are used.
Other properties tested in industry include bursting strength, tear index, stiffness,
compressibility, and wet strength
Tensile Strength Testing
25 mm strips of algal paper were tested for tensile strength against regular printer paper
A Mark-10 Force Gage Model M5-200 Instron was used to test the tensile strengths of the sample papers
The samples of each paper were used in the instron and the peak force before breaking was recorded
Each paper type was sampled five times
Tensile Strength Testing Lab Results
Type of Paper (25mm strips)
Caliper (mm)
Average Peak Force (N)
Tensile Strength (N/m)
Basis Weight (g/m2)
Breaking Length(km)
Tensile Index(Nm/g)
Printer 1.016 49.3 1970 72.9 2.76 27.1
Algae 3.07 22.9 916 127 0.735 7.21
Governing Equations: Tensile Testing
Tensile Strength (TS) [N/m]
F = Peak Force
w = Width of test strip
Breaking Length (BL) [km]
BW = Basis Weight (g/m2)
Tensile Index (TI) [Nm/g]
Stella Model
Volume: 1000000 L
Flow rate: 40000 L/hr
Hydraulic retention time: 25hr
Cell concentration: 30g/
Cell retention time: 47 hr.
Harvest flow: .64 g/L/h
Yield: 14 kg/day
Stella Model
SuperPro
Sustainability
Can be used to help sequester carbon
Make use of problematic algal blooms
Chemical pulping techniques are not required for algae as in traditional paper pulping
Bleaching can be accomplished through drying and UV light
http://www.clemson.edu/extension/natural_resources/water/stormwater_ponds/problem_solving/aquatic_weeds/algae_filamentous/
Budget from Super pro
Budget Cont.
Gantt Chart
Conclusion: User Answers
- Will traditional pens and pencils write legibly on Algal paper?
- Yes, if the color can be contrasted properly
- Is the algal paper as durable as comparable traditional papers?
- No, but it is functional
- Will the paper last as long as traditional papers?
- Unknown, could not test in allotted time
Conclusion: Client Answers
- What is required to grow algae for paper making?
- A simple CSTR with proper nutrients
- Can algal pulp be processed using similar equipment to traditional pulp
- Very similar equipment can be used, process is actually much simpler
- Can wood and algae pulp be mixed?
- Unknown. Should be able to but it would impact strength
Conclusions: Designer
- What type of paper is desired by the client (loose leaf, card stock, etc)?
- In this case a writing stationery was selected
- What will be the required strength of the pressed paper?
- Ideally around 50 N
- What type of algae will be used?
- Pithophora oedogonia, in this climate
Conclusions
Biological- A 1,000,000L tank was needed to produce the 14400 kg of algae/day for the
process.- Found that UV could be an effective means of whiting paper
Structural - Our test paper was not as strong as printer paper
- A more controlled process could yield better results. Mechanical
- We designed a process that should yield 1.8 million 8.5 x 11in sheets per day.
Thank You!Dr. Caye Drapcho
Dr. Terry Walker
Mr. Tom Jones
Cassidy Laird
Dr. Scott Whiteside
Clemson University
ReferencesAyhan Demirbas, M. F. (2011). Importance of algae oil as a source of biodiesel. Energy Conversion and Management, Vol. 52, 163-170. <http://www.sciencedirect.com/science/article/pii/S0196890410002761>
Teschke, K. (n.d.). Chapter 72 - Pulp and Paper Industry. Encyclopedia of Occupational Health and Safety, Chapt. 72. <http://www.ilocis.org/documents/chpt72e.htm>
Global Greenhouse Gas Reference Network (2016). Trends in Atmospheric Carbon Dioxide: Full Mauna Loa CO2 record. Earth System Research Laboratory.<http://www.esrl.noaa.gov/gmd/ccgg/trends/full.html>
Ben Xu, P. L. (2013). Study of the Flow Mixing in a novel ARID raceway for algae production. Renewable Energy Vol. 62, 249-257. <http://www.sciencedirect.com/science/article/pii/S096014811300342X>
Environmental Protection Agency (1990). Chemical Wood Pulping. Compilation of Air Pollutant Emission Factors, Ch 10 S02 <https://www3.epa.gov/ttnchie1/ap42/ch10/final/c10s02.pdf>
South Carolina Department of Natural Resources (2015). Fish Pond Management Information. Common Aquatic Plant Management Problems.<http://www.dnr.sc.gov/water/aquaff/pithalgae.html>
Georgia Tech School of Economics (2003-16). Pulp Mills, Pulp & Paper Mills, Paper Mills in South Carolina. Center for Paper Business and Industry Studies.<http://www.cpbis.gatech.edu/data/mills-online-new?state=South+Carolina>
ReferencesStein, T. (2016). Carbon dioxide levels race past troubling milestone. National Oceanic and Atmospheric Administration. <http://www.noaa.gov/stories/carbon-dioxide-levels-race-past-troubling-milestone>
Kapstone. (2016). About Kapstone. Kapstone Paper and Packaging Corporation. <http://www.kapstonepaper.com/about-kapstone/>
Pokhrel, D., Viraraghavan, T. (2004). Treatment of pulp and paper mill wastewater--a review. Science of the Total Environment. Vol. 333, Issues 1-3. <http://www.sciencedirect.com/science/article/pii/S0048969704004279>.
Kocamemi, B. A., (n.d.). Environmental Engineering Unit Operations, Chapter 6 Mixing. Marmara University Department of Environmental Engineering. <http://mimoza.marmara.edu.tr/~bilge.alpaslan/enve301/Lectures/Chp_6.pdf>.
Questions?
Preguntas?
Les questions?
Appendices
Handsheet notes and thickness calculations Blending notes and handsheet pressure calculations
Appendices
Hand Calculations for Superpro Scale up
Appendices
Hand Calculations for Superpro Scale up
Appendices
http://www.paperonweb.com/paperpro.htm
Appendices
http://www.paperonweb.com/paperpro.htm