This document compares biodiesel and petroleum diesel in terms of their fuel properties, engine exhaust emissions, production trends, and scenario analysis. It finds that biodiesel emits less particulate matter, hydrocarbons, and carbon monoxide but more oxides of nitrogen than petroleum diesel. A scenario analysis shows that using 100% biodiesel instead of petroleum diesel could reduce emissions of these pollutants by millions of metric tons annually in the United States. The document also discusses challenges with biodiesel including higher NOx emissions and potential engine issues.

1. Biodiesel versus Diesel
Air Quality & Economic Aspects
Student Presentation
ENV5015: Fundamentals of Air Pollution
April 17, 2017
Project Report: https://goo.gl/9MQNVV
kalaivanan murthy
comparison of biodiesel and petroleum diesel

2. Contents
• Biodiesel: An Overview
• Trends: Production & Consumption
• Biodiesel: Fuel Properties
• Engine Exhaust Emissions
• Scenario Analysis
• Conclusion
• References
Picture Credit: NESTE (NEXBTL) 2
BIODIESEL PETROLEUM DIESEL

3. Biodiesel: An Overview
• Biodiesel is a fuel produced from vegetable or animal oil by transesterification process.
• Biodiesel is environment friendly: biodegradable, renewable, non-toxic, carbon-neutral fuel.
• In 2016, the consumption of biodiesel in US is 2.06 billion gallons. In 2001, it was 0.01 billion gallons.
This is 20,500% increase (since 2001).
• Biodiesel is domestically produced and it is non-toxic (free from spill hazards).
• Biodiesel is cleaner fuel in regard to exhaust emissions. Compared to petroleum diesel, biodiesel
emits lesser particulate matter, hydrocarbons, carbon monoxide. It is also free from sulfur emissions.
• In general, diesel (compression combustion) outperforms gasoline (ignition combustion) in many
factors: fuel economy, hauling capacity, long-range driving, carbon dioxide emissions.
• Biodiesel has some challenges. Compared to petroleum diesel, NOx emissions are higher for
biodiesel. This is due to increased oxygen content and high peak pressure in combustion.
• Biodiesel cannot be 100% replaced in automobile engines – not because of the fuel – but because of
the engine compatibility. It is also found to leave sediments and deposits.
3

4. Trends: Production & Consumption
• In 2001, the annual consumption
was 10.27 million gallons (0.010
billion gallons). That was just
0.03% of No.2 Diesel produced.
• In last five years (2011-2015), an
average of 1.23 billion gallons of
biodiesel was consumed annually.
This corresponds to an average of
3.25% of No.2 Diesel produced in
the same year.
• The figure shows an increasing
trend, which implies biodiesel is
gaining popularity. (exponential)
4
0.00
500.00
1000.00
1500.00
2000.00
2500.00
2001 2003 2005 2007 2009 2011 2013 2015
AnnualAmount(milliongal)
Time
Biodiesel Statistics of US
Consumption (Mgal) Production (Mgal) Poly. (Consumption (Mgal))

5. Biodiesel: Properties
Property Units Petroleum Diesel Biodiesel
Soy Methyl Ester
(SME)
Viscosity 40 °C, cSt 2.0-3.5 3.5-5.5 4.7
Density 15 °C, g cm-3 0.81-0.86 0.87-0.89 0.88
Oxygen % mass ≅0 10-11 NA
Cetane Number - 40-45 45-55 56.4
Energy MJ/kg 42.5-44 36.5-38 37.1
Sulfur % mass 0.0015-0.05 ≅0 NA
Aromatics % mass 30 ≅0 NA
Flash Point °C 64 NA 169
5

6. Exhaust Emission: NOx
• Biodiesel emits higher NOx than petroleum diesel. (positive effect)
• Increase in NOx emission is 12% for B100 and 6% for B20.
• Difference in NOx emission increases at higher engine loads.
• Higher NOx is due to:
• higher oxygen
• higher peak pressure
• advanced ignition
• higher cetane number
• Relative reduction is nearly same for all blends through B100 (linear relationship). No significant
increase was observed with B5.
• NOx emissions decreased with decreasing viscosity.
6

7. Exhaust Emission: PM
• Biodiesel emits lesser particulate matter than petroleum diesel. (negative effect)
• Maximum reduction achieved was 60% for B100, and 20% for B20.
• Main components of particulate matter:
• soot
• sulfate
• PAH (adsorbed over aerosols.)
• Reduction in PM was due to oxygen, which oxidizes the otherwise formed soot, and absence of
sulfur and PAH compounds.
• Relative reduction was higher for B20-B25 blends. (Some studies report B30.)
• Additionally, PM reductions were maximum in indirect-injection engines (an effect of engine-type on
emission characteristics).
7

8. Exhaust Emission: HC
• Biodiesel emits lesser hydrocarbons (HC) than petroleum diesel. (negative effect)
• The reduction achieved was up to 70% for B100, and 32% for B20.
• Reduced HC emissions was due to:
• higher oxygen (complete combustion)
• higher cetane number (reduced combustion delay)
• advanced injection
• peroxide (due to hydrocarbon oxidation)
• Relative reduction was higher for B25.
• Additionally, HC emissions was decreased with oxygenated biodiesel. (biodiesel with added oxygen
additives.)
8

9. Exhaust Emission: CO
• Biodiesel emits lesser carbon monoxide than petroleum diesel. (negative effect)
• The reduction was nearly 50% for B100, and 15% for B20.
• The reduction in CO was due to:
• higher oxygen
• higher cetane number (lesser fuel-rich zones)
• combustion advancement
• advanced injection
• Relative reduction is almost same for all blends through B100. (linear relationship)
• CO was increased upon adding cetane enhancer. (additives to enhance cetane number.)
9

10. Exhaust Emissions: Summary
• Overall, biodiesel has cleaner emissions than petroleum diesel. NOx is an exception.
• Positive or Increasing Effect: NOx
• Negative or Decreasing Effect: PM, CO, HC (including VOC)
• Absence: Sulfur, PAH
• Differences in B20:
• NOx +6%
• PM -20%
• HC -32%
• CO -15%
10

11. Scenario Analysis
• Since 2001, a total of 9.84 billion gallons of biodiesel has been used. The corresponding gross
savings is given below.
• In past five years (2011-2015), an average of 37.17 billion gallons of petroleum diesel has been
consumed annually. The annual savings in two alternative scenarios are given below (BD100, B20).
11
Unit PD-Emissions
(m3/m3)
Unit PD-Emissions
(kg/gal)
Unit BioD-Emissions
(kg/gal)
Emissions
Million Metric Tons
(If Diesel)
Emissions
Million Metric Tons
(If B100 used)
Emission Savings
Million Metric Tons
B100
CO2 81.8182 0.3794 0.0000 3734.2934 0.0000 3734.2934
NOx 0.7959 0.0037 0.0047 36.3245 46.5089 -10.1844
CO 0.3570 0.0017 0.0010 16.2951 9.5055 6.7896
HC 0.0417 0.0002 0.0001 1.9011 0.8827 1.0184
Unit PD-Emissions
(m3/m3)
Unit PD-Emissions
(kg/gal)
Unit BioD-Emissions
(kg/gal)
Emissions
Million Metric Tons
(If Diesel)
Emissions
Million Metric Tons
(If B100 used)
Emission Savings
Million Metric Tons
B100
Emission Savings
Million Metric Tons
B20
CO2 81.8182 0.3794 0.0000 14103.1050 0.0000 14103.1050 2820.6210
NOx 0.7959 0.0037 0.0047 137.1847 175.6478 -38.4630 -7.6926
CO 0.3570 0.0017 0.0010 61.5408 35.8988 25.6420 5.1284
HC 0.0417 0.0002 0.0001 7.1798 3.3335 3.8463 0.7693
Note: The CO2 emissions for biodiesel is shown zero. It is because the CO2 emitted by biodiesel is absorbed back by plants.

12. Challenges
• Factors influencing emission are:
• loading: full, partial loading condition
• engine technology: direct injection, indirect injection
• engine speed
• exhaust gas recirculation
• vehicle type: heavy duty, light duty
• Engines specific to biodiesel to obtain maximum efficiency.
• Use of B5 or B20 is subject to manufacturers warranty.
• Control technologies to be designed specific to biodiesel engines.
12

13. Conclusion
• Benefits with Biodiesel: PM, HC (incl. VOC), CO, Ozone, Sulfur, PAH
• Challenges with Biodiesel: NOx
• Other Benefits: non-toxic, biodegradable.
• Other Challenges: sedimentation, deposits
• The benefit achieved by biodiesel is more sustainable than petroleum diesel.
• These challenges can be overcome by: using additives, controlling ignition time or designing
biodiesel specific combustion engines.
• B20 has tremendous potential in near future (5-10 years). Scope for B100 depends on
manufacturers warranty.
13

14. References
[1] Energy Information Administration - United States, Monthly Energy Review, Biodiesels and other renewable fuels overview, Retrieved: April 10, 2017.
https://www.eia.gov/totalenergy/data/monthly/index.php#renewable
[2] Environmental Protection Agency - United States, A comprehensive analysis of biodiesel impacts on exhaust emissions, Retrieved: April 10, 2017.
https://www3.epa.gov/otaq/models/analysis/biodsl/p02001.pdf
[3] Bureau of Transportation Statistics, Diesel-powered Passenger Cars and Light Trucks, Retrieved: April 10, 2017.
https://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/bts_fact_sheets/oct_2015/html/entire.html
[4] Alternative Fuels Data Center, Biodiesel Blends, Retrieved on April 10, 2017, http://www.afdc.energy.gov/fuels/biodiesel_blends.html
[5] Buyukkaya, E. (2010). Effects of biodiesel on a DI diesel engine performance, emission and combustion characteristics. Fuel, 89(10), 3099-3105.
[6] Szybist, J.P., Song, J., Alam, M., Boehman, A.L. (2007).Biodiesel combustion, emissions and emission control. Fuel processing technology, 88(7), 679-691.
[7] Palash, S. M., Kalam, M. A., Masjuki, H. H., Masum, B. M., Fattah, I. R., & Mofijur, M. (2013). Impacts of biodiesel combustion on NO x emissions and their
reduction approaches. Renewable and Sustainable Energy Reviews, 23, 473-490.
[8] Schumacher, L. G., Marshall, W., Krahl, J., Wetherell, W. B., & Grabowski, M. S. (2001). Biodiesel emissions data from series 60 DDC engines.
Transactions-American Society of Agricultural Engineers, 44(6), 1465-1468.
[9] Zou, L., & Atkinson, S. (2003). Characterising vehicle emissions from the burning of biodiesel made from vegetable oil. Environmental technology, 24(10),
1253-1260.
[10] Dincer, K. (2008). Lower emissions from biodiesel combustion. Energy Sources, Part A, 30(10), 963-968.
[11] Bakeas, E., Karavalakis, G., & Stournas, S. (2011). Biodiesel emissions profile in modern diesel vehicles. Part 1: Effect of biodiesel origin on the criteria
emissions. Science of the total environment, 409(9), 1670-1676.
[12] Karavalakis, G., Boutsika, V., Stournas, S., & Bakeas, E. (2011). Biodiesel emissions profile in modern diesel vehicles. Part 2: Effect of biodiesel origin on
carbonyl, PAH, nitro-PAH and oxy-PAH emissions. Science of the total Environment, 409(4), 738-747.
[13] Rounce, P., Tsolakis, A., Leung, P., & York, A. P. E. (2010). A comparison of diesel and biodiesel emissions using dimethyl carbonate as an oxygenated
additive. Energy & Fuels, 24(9), 4812-4819.
[14] Lapuerta, M., Armas, O., & Rodriguez-Fernandez, J. (2008). Effect of biodiesel fuels on diesel engine emissions. Progress in energy and combustion
science, 34(2), 198-223.
[15] Wang, W. G., Lyons, D. W., Clark, N. N., Gautam, M., & Norton, P. M. (2000). Emissions from nine heavy trucks fueled by diesel and biodiesel blend
without engine modification. Environmental Science & Technology, 34(6), 933-939.
14

15. References (cntd.)
[16] Monyem, A., & Van Gerpen, J. H. (2001). The effect of biodiesel oxidation on engine performance and emissions. Biomass and bioenergy, 20(4), 317-
325.
[17] McCormick, R. L., Graboski, M. S., Alleman, T. L., Herring, A. M., & Tyson, K. S. (2001). Impact of biodiesel source material and chemical structure on
emissions of criteria pollutants from a heavy-duty engine. Environmental science & technology, 35(9), 1742-1747.
[18] Ireland, J., McCormick, R., Yanowitz, J., & Wright, S. (2009). Improving biodiesel emissions and fuel efficiency with fuel-specific engine calibration (No.
2009-01-0492). SAE Technical Paper.
[19] Hoekman, S. K., & Robbins, C. (2012). Review of the effects of biodiesel on NOx emissions. Fuel Processing Technology, 96, 237-249.
[20] Nabi, M. N., Akhter, M. S., & Shahadat, M. M. Z. (2006). Improvement of engine emissions with conventional diesel fuel and diesel–biodiesel blends.
Bioresource Technology, 97(3), 372-378.
[21] Fontaras, G., Karavalakis, G., Kousoulidou, M., Tzamkiozis, T., Ntziachristos, L., Bakeas, E., ... & Samaras, Z. (2009). Effects of biodiesel on passenger
car fuel consumption, regulated and non-regulated pollutant emissions over legislated and real-world driving cycles. Fuel, 88(9), 1608-1617.
[22] He, C., Ge, Y., Tan, J., You, K., Han, X., Wang, J., ... & Shah, A. N. (2009). Comparison of carbonyl compounds emissions from diesel engine fueled with
biodiesel and diesel. Atmospheric Environment, 43(24), 3657-3661.
[23] Chai, M., Lu, M., Liang, F., Tzillah, A., & Dendramis, N. (2013). The use of biodiesel blends on a non-road generator and its impacts on ozone formation
potentials based on carbonyl emissions. Environmental pollution, 178, 159-165.
[24] Alternative Fuels Data Center, Fuel Properties Comparison, Retrieved: April 14, 2017. http://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf
[25] Guider, T. P. (2008). Characterization of Engine Performance with Biodiesel Fuels (Doctoral dissertation, Masters Thesis, Lehigh University).
[26] Xue, J., Grift, T. E., & Hansen, A. C. (2011). Effect of biodiesel on engine performances and emissions. Renewable and sustainable energy reviews,
15(2), 1098-1116.
[27] Nett Technologies Inc., What are diesel engines, Retrieved: April 13, 2017, https://www.nettinc.com/information/emissions-faq/what-are-diesel-emissions
[28] Dieselnet, Emission Standards, Retrieved: April 13, 2017, https://www.dieselnet.com/standards/
[29] Shirneshan, A. (2013). HC, CO, CO2 and NOx emission evaluation of a diesel engine fueled with waste frying oil methyl ester. Procedia-Social and
Behavioral Sciences, 75, 292-297.
[30] Reşitoğlu, İ. A., Altinişik, K., & Keskin, A. (2015). The pollutant emissions from diesel-engine vehicles and exhaust after treatment systems. Clean
Technologies and Environmental Policy, 17(1), 15-27.
15

16. Acknowledgement
• Dr. Myoseon Jang
Associate Professor, Department of Environmental
Engineering Sciences, University of Florida.
Atmospheric and Air Quality Scientist (Specialty:
Heterogeneous Chemistry of Organic Compounds, Air
Pollutant Characterization and Modeling)
• Mr. Trevor Tilly, PhD Student
Graduate Student Research Assistant, Department of
Environmental Engineering Sciences, University of Florida.
16

17. Biodiesel versus Diesel
Air Quality & Economic Aspects
Student Presentation
ENV5015: Fundamentals of Air Pollution
April 17, 2017
Project Report: https://goo.gl/9MQNVV
kalaivanan murthy
Thank You

18. Appendix: How Biodiesel is made?
• The following flow chart summarizes the production of biodiesel.
18

19. Appendix: How Biodiesel is made? (cntd.)
• An insight of transesterification reaction.
19