Beneficial utilization of waste coffee ground for biodiesel production
Beneficial utilization of waste coffee ground for biodiesel production 105th Annual Conference of Air & Waste Management Association San Antonio, TX June 18-22, 2012
Qingshi Tu Mingming Lu Ming Chai University of Cincinnati
Agenda • Introduction – US biodiesel industry – Technical issues – WCG as a solution
• • • • • •
Goal and scope Methodology Results and discussion Conclusion Future work References
US biodiesel industry • A few numbers about US biodiesel industry – – – –
-48% CO, -47% PM, -80% PAHs, -100% SO2 Fossil energy return (FER) 5.54:1(Pradhan et al. 2011) Over 1 billion gallons of biodiesel produced in 2011 (NBB,2012) 194 plants, total capacity over 2.9 billion gallons per year (Biodiesel Magazine, 2012)
– Soybean accounted for a large share of feedstock market • 80% in 2007, 56% in 2008, 49.2% in 2009 (USDA 2011)
– Average irrigation for soybean • 228,095 gallons/acre (USDA 2008) Feedstock development
Oil processing
Biodiesel production
Technical issues Feedstock supply issue
Challenge in purification
Post-purification disposal
• Moderate oil content; substantial supply • Suitable for current technology
• Constringent specifications • Cost-effectiveness
• Non-hazardous • Environmentally-friendly
Waste coffee grounds as a solution •
WCG supply potential – –
•
WCG as the oil source – –
•
Oil concentration in WCG is usually around 10-20 wt% Both lipids and FFAs from coffee beans and grounds mainly consisted of long oxygenated carbon chains, such as C16:0, C18:0, C18:1, and C18:2.
WCG as purification material – –
•
Annual personal consumption of coffee: 24.2 gallons/yr (US Bureau of Census 2008)…which translates into...11.1 lbs waste coffee ground per capita per year (Specialty Coffee Association of America) If assuming 10 wt% oil content (Kondamudi et al. 2008), the oil supply for biodiesel could be 44 million gallons per year in the US (based on 2008 population data).
Effective substrate for AC preparation Effective adsorbent for heavy metal, cation dyes, phenols, etc.
WCG as fuel – –
High energy potential: combustion of 1 kg of coffee grounds in municipal incineration could generate 0.53 kWh electricity and 3.92 MJ of useful heat (ESU-Services Ltd., 2011) Adjunct fuel with coal (ABC, 2012)
Characterization of WCG •
Characterization of WCG (general) – – –
–
•
Particle size distribution depends on the grinding process High moisture content Chemical composition (Azouaou et al. 2010) • C+O: ~92% • Various metal oxides Acidity (free fatty acid leaching out)
Current fates of WCG – – – – –
Gardening material/composting (e.g. Starbucks “Grounds for Your Garden”) Odor control (e.g. toilet deodorant) Pest control Furniture scratch touch-up Landfill
Benefits of using WCG for biodiesel production • • • • •
Enriching the feedstock market, lowering the production cost Lowering the purification cost Saving cost for electricity generation by replacing coal with WCG (after oil extraction and purification) Reducing the solid waste disposal issue, and subsequently saving land Protecting water resources: 1) less contamination by WCG landill leachate; 2) elimination of water consumption and wastewater generation for crude biodiesel purification
7
Goal and scope •
The overall goal is to utilize the WCG in a closed-loop manner for biodiesel production: – –
• •
Oil extraction from WCG for feedstock supply Purification of crude biodiesel by using WCG (after extraction) as a polishing material
The last piece of the loop, “heat/power generation by burning spent WCG”, is not included in the current scope of the study. In addition, the current study is focused on lab-scale R&D and the results presented in the thesis are based on the preliminary experiments.
8
Methodology •
Materials – –
– –
•
WCG: Starbucks® “grounds for your garden” program in the West Campus of University of Cincinnati Solvents: n-hexane (99.9%, HPLC grade), isopropanol (99.9%, HPLC grade), and heptane (99.9%, HPLC grade) from UC chemistry stockroom Crude biodiesel: BlueGrass Biodiesel® (KY, USA) Commercial dry washing materials: D-Sol (C400)TM from Dallas Group of America, Inc (TX, USA) and the ion-exchange resin from ALX
Analytical methods – –
Total oil recovery: wt% of oil to WCG dry mass (weighing by analytical balance) Purification effectiveness: ASTM standards
9
Methodology •
Oil extraction – – – – –
•
Around 10 g WCG is baked in the oven overnight to remove the moisture. Oil extraction is performed through soxhlet system 3 individual solvents and 1 mixture are tested Both short extraction time (45 min) and long extraction time (7 hrs) are tested After extraction, the oil is separated from the solvent through the rotary evaporator
Post-extraction WCG as purification material – – – – –
The designated amount of WCG (after extraction) is baked to remove trace solvent) WCG is packed in the graduated column, where crude biodiesel flows through by gravity In the end of each purification run, a sample was withdrawn to check the purification effect for each ASTM specification. WCG-to-crude biodiesel ratio (wt/v) is fixed at 1:10 3 purification trials have been performed
10
Results and discussion • Oil recovery Solvent
Extraction Time (hr)
Extraction Rate (wt%)
Note
Heptane
0.5-0.75
8.37
Averaged from 7 batches
Hexane
7
8.88
Isopropanol
7
9.23
Hexane/Isopropanol (1:1)
7
11.62
1:1 v/v mixture
11
Results and discussion • Composition – Moisture: 20-50 wt%, depending on factors such as time between disposal and collection, environment for disposal – Ultimate analysis for grounds:
Element
Percentage
C
54.26
H
7.3
N
2.38
O
35.3
S
0.15
Others
0.61
12
Results and discussion •
1st purification trial
Upper left: (a)-effect on AN; upper right: (b)-effect on moisture; lower left: (c)-effect on residual MeOH; lower right: (d)-effect on residual free glycerin
Results and discussion •
2nd purification trial
Upper left: (a)-effect on AN; upper right: (b)-effect on moisture; lower left: (c)-effect on residual MeOH; lower right: (d)-effect on residual free glycerin
Results and discussion •
2nd purification trial (cont’d)
Purification Results of Second Run (Na+Ca)
Results and discussion •
3rd purification trial
Upper left: (a)-effect on AN; upper right: (b)-effect on moisture; lower left: (c)-effect on residual MeOH; lower right: (d)-effect on residual free glycerin
Results and discussion •
3rd purification trial (cont’d)
Upper left: (e)-effect on Na+K; upper right: (f)-effect on Ca+Mg; lower left: (g)-effect on P; lower right: (h)-effect on S
Conclusion •
Qualitative summary of purification effects by different materials based on the preliminary results
18
Conclusion •
Removal rates of some impurities by different purification materials
19
Future Work •
Clarifying the uncertainties regarding oil extraction from WCG, such as solvent selection vs extraction outcome, influence of solvent on oil composition, optimal extraction time, etc.;
•
Clarifying the uncertainties regarding purification effectiveness, such as effect on moisture, initial concentration of impurity vs removal efficiency, etc.;
•
Testing the effectiveness in removing S
•
Study the properties (e.g. surface area, morphology), and purification mechanisms of WCG;
•
Finding the influence of dosing (WCG-to-crude biodiesel ratio; wt/v) on the purification;
•
Performing combustion tests on burning spent WCG (after purification) to obtain the knowledge of its heat/power generation potential as well as the emission profile to the environment.
20
References • • • • • • • • • •
National Biodiesel Board. See http://www.biodiesel.org (accessed on January 2012). U.S. Bureau of Census. See http://www.census.gov (accessed on January 2012). Specialty Coffee Association of America. See http://www.scaa.org/ (accessed on January 2012). Oliveira, L. S.; Franca, A. S.; Camargos, R. R. S.; and Ferraz, V. P. Bioresource Technol. 2008, 99, 3244-3250. ASTM D6751 Standard specification for biodiesel fuel blend stock (B100) for middle distillate fuels. See http://www.astm.org/Standards/D6751.htm (accessed on January 2012). Kondamudi, N.; Mohapata, S. K.; and Misra, J. Agric. Food Chem. 2008, 56, 11757-11760. Nunes, A. A.; Franca, A. S.; and Oliveira, L. S. Bioresource Technol. 2009, 100, 1786-1792. Franca. A. S.; Oliveira, L. S.; Nunes, A. A; and Alves, C. C. O. Bioresource Technol. 2010, 101, 1068-1074. Faccini, C.S.; De Cunha, M.E.; Moraes, M.S.A.; Krause, L.C.; Manique, M.C.; Rodrigues, M.R.A.; Benvenutti, E.V.; and Caramao, E.B. J. Braz, Chem. Soc. 2011, 22, no3, 558-563. Berezin, O.Y.; Tur’an Y.I.; Kuselman, I.; and Shenhar, A. JAOCS. 1996, 73, 1707-1711.
Thank You
Contact Qingshi Tu [email protected]
Qingshi Tu Mingming Lu Ming Chai University of Cincinnati
Agenda • Introduction – US biodiesel industry – Technical issues – WCG as a solution
• • • • • •
Goal and scope Methodology Results and discussion Conclusion Future work References
US biodiesel industry • A few numbers about US biodiesel industry – – – –
-48% CO, -47% PM, -80% PAHs, -100% SO2 Fossil energy return (FER) 5.54:1(Pradhan et al. 2011) Over 1 billion gallons of biodiesel produced in 2011 (NBB,2012) 194 plants, total capacity over 2.9 billion gallons per year (Biodiesel Magazine, 2012)
– Soybean accounted for a large share of feedstock market • 80% in 2007, 56% in 2008, 49.2% in 2009 (USDA 2011)
– Average irrigation for soybean • 228,095 gallons/acre (USDA 2008) Feedstock development
Oil processing
Biodiesel production
Technical issues Feedstock supply issue
Challenge in purification
Post-purification disposal
• Moderate oil content; substantial supply • Suitable for current technology
• Constringent specifications • Cost-effectiveness
• Non-hazardous • Environmentally-friendly
Waste coffee grounds as a solution •
WCG supply potential – –
•
WCG as the oil source – –
•
Oil concentration in WCG is usually around 10-20 wt% Both lipids and FFAs from coffee beans and grounds mainly consisted of long oxygenated carbon chains, such as C16:0, C18:0, C18:1, and C18:2.
WCG as purification material – –
•
Annual personal consumption of coffee: 24.2 gallons/yr (US Bureau of Census 2008)…which translates into...11.1 lbs waste coffee ground per capita per year (Specialty Coffee Association of America) If assuming 10 wt% oil content (Kondamudi et al. 2008), the oil supply for biodiesel could be 44 million gallons per year in the US (based on 2008 population data).
Effective substrate for AC preparation Effective adsorbent for heavy metal, cation dyes, phenols, etc.
WCG as fuel – –
High energy potential: combustion of 1 kg of coffee grounds in municipal incineration could generate 0.53 kWh electricity and 3.92 MJ of useful heat (ESU-Services Ltd., 2011) Adjunct fuel with coal (ABC, 2012)
Characterization of WCG •
Characterization of WCG (general) – – –
–
•
Particle size distribution depends on the grinding process High moisture content Chemical composition (Azouaou et al. 2010) • C+O: ~92% • Various metal oxides Acidity (free fatty acid leaching out)
Current fates of WCG – – – – –
Gardening material/composting (e.g. Starbucks “Grounds for Your Garden”) Odor control (e.g. toilet deodorant) Pest control Furniture scratch touch-up Landfill
Benefits of using WCG for biodiesel production • • • • •
Enriching the feedstock market, lowering the production cost Lowering the purification cost Saving cost for electricity generation by replacing coal with WCG (after oil extraction and purification) Reducing the solid waste disposal issue, and subsequently saving land Protecting water resources: 1) less contamination by WCG landill leachate; 2) elimination of water consumption and wastewater generation for crude biodiesel purification
7
Goal and scope •
The overall goal is to utilize the WCG in a closed-loop manner for biodiesel production: – –
• •
Oil extraction from WCG for feedstock supply Purification of crude biodiesel by using WCG (after extraction) as a polishing material
The last piece of the loop, “heat/power generation by burning spent WCG”, is not included in the current scope of the study. In addition, the current study is focused on lab-scale R&D and the results presented in the thesis are based on the preliminary experiments.
8
Methodology •
Materials – –
– –
•
WCG: Starbucks® “grounds for your garden” program in the West Campus of University of Cincinnati Solvents: n-hexane (99.9%, HPLC grade), isopropanol (99.9%, HPLC grade), and heptane (99.9%, HPLC grade) from UC chemistry stockroom Crude biodiesel: BlueGrass Biodiesel® (KY, USA) Commercial dry washing materials: D-Sol (C400)TM from Dallas Group of America, Inc (TX, USA) and the ion-exchange resin from ALX
Analytical methods – –
Total oil recovery: wt% of oil to WCG dry mass (weighing by analytical balance) Purification effectiveness: ASTM standards
9
Methodology •
Oil extraction – – – – –
•
Around 10 g WCG is baked in the oven overnight to remove the moisture. Oil extraction is performed through soxhlet system 3 individual solvents and 1 mixture are tested Both short extraction time (45 min) and long extraction time (7 hrs) are tested After extraction, the oil is separated from the solvent through the rotary evaporator
Post-extraction WCG as purification material – – – – –
The designated amount of WCG (after extraction) is baked to remove trace solvent) WCG is packed in the graduated column, where crude biodiesel flows through by gravity In the end of each purification run, a sample was withdrawn to check the purification effect for each ASTM specification. WCG-to-crude biodiesel ratio (wt/v) is fixed at 1:10 3 purification trials have been performed
10
Results and discussion • Oil recovery Solvent
Extraction Time (hr)
Extraction Rate (wt%)
Note
Heptane
0.5-0.75
8.37
Averaged from 7 batches
Hexane
7
8.88
Isopropanol
7
9.23
Hexane/Isopropanol (1:1)
7
11.62
1:1 v/v mixture
11
Results and discussion • Composition – Moisture: 20-50 wt%, depending on factors such as time between disposal and collection, environment for disposal – Ultimate analysis for grounds:
Element
Percentage
C
54.26
H
7.3
N
2.38
O
35.3
S
0.15
Others
0.61
12
Results and discussion •
1st purification trial
Upper left: (a)-effect on AN; upper right: (b)-effect on moisture; lower left: (c)-effect on residual MeOH; lower right: (d)-effect on residual free glycerin
Results and discussion •
2nd purification trial
Upper left: (a)-effect on AN; upper right: (b)-effect on moisture; lower left: (c)-effect on residual MeOH; lower right: (d)-effect on residual free glycerin
Results and discussion •
2nd purification trial (cont’d)
Purification Results of Second Run (Na+Ca)
Results and discussion •
3rd purification trial
Upper left: (a)-effect on AN; upper right: (b)-effect on moisture; lower left: (c)-effect on residual MeOH; lower right: (d)-effect on residual free glycerin
Results and discussion •
3rd purification trial (cont’d)
Upper left: (e)-effect on Na+K; upper right: (f)-effect on Ca+Mg; lower left: (g)-effect on P; lower right: (h)-effect on S
Conclusion •
Qualitative summary of purification effects by different materials based on the preliminary results
18
Conclusion •
Removal rates of some impurities by different purification materials
19
Future Work •
Clarifying the uncertainties regarding oil extraction from WCG, such as solvent selection vs extraction outcome, influence of solvent on oil composition, optimal extraction time, etc.;
•
Clarifying the uncertainties regarding purification effectiveness, such as effect on moisture, initial concentration of impurity vs removal efficiency, etc.;
•
Testing the effectiveness in removing S
•
Study the properties (e.g. surface area, morphology), and purification mechanisms of WCG;
•
Finding the influence of dosing (WCG-to-crude biodiesel ratio; wt/v) on the purification;
•
Performing combustion tests on burning spent WCG (after purification) to obtain the knowledge of its heat/power generation potential as well as the emission profile to the environment.
20
References • • • • • • • • • •
National Biodiesel Board. See http://www.biodiesel.org (accessed on January 2012). U.S. Bureau of Census. See http://www.census.gov (accessed on January 2012). Specialty Coffee Association of America. See http://www.scaa.org/ (accessed on January 2012). Oliveira, L. S.; Franca, A. S.; Camargos, R. R. S.; and Ferraz, V. P. Bioresource Technol. 2008, 99, 3244-3250. ASTM D6751 Standard specification for biodiesel fuel blend stock (B100) for middle distillate fuels. See http://www.astm.org/Standards/D6751.htm (accessed on January 2012). Kondamudi, N.; Mohapata, S. K.; and Misra, J. Agric. Food Chem. 2008, 56, 11757-11760. Nunes, A. A.; Franca, A. S.; and Oliveira, L. S. Bioresource Technol. 2009, 100, 1786-1792. Franca. A. S.; Oliveira, L. S.; Nunes, A. A; and Alves, C. C. O. Bioresource Technol. 2010, 101, 1068-1074. Faccini, C.S.; De Cunha, M.E.; Moraes, M.S.A.; Krause, L.C.; Manique, M.C.; Rodrigues, M.R.A.; Benvenutti, E.V.; and Caramao, E.B. J. Braz, Chem. Soc. 2011, 22, no3, 558-563. Berezin, O.Y.; Tur’an Y.I.; Kuselman, I.; and Shenhar, A. JAOCS. 1996, 73, 1707-1711.
Thank You
Contact Qingshi Tu [email protected]
