Combustion Chemistry of Biodiesel for the Use in Urban Transport Buses
Biodiesel has many advantages over petroleum-based diesel and other renewable fuels. The use of biodiesel is less harmful to human health and environment and compared to other renewable energy, biodiesel has a broader range of feedstock resources, and is more economical to produce. Compatibility with the existing diesel engines and infrastructure is also a great advantage. Theoretically, biodiesel may be directly used on the current diesel engines without much extra modification. Not only is there less oxides of nitrogen (NOx) produced, but the most popular 20% biodiesel has demonstrated performance on a par with regular diesel. Most engine manufacturers allow up to 20% blends of biodiesel without voiding the warranty. Despite its ever increasing production and consumption, and its potential as a competent alternative energy in the future, there are many unknowns about biodieselís combustion mechanisms, performance, and environmental and health impacts.
The characterization of the combustion behavior of biodiesel and modeling of its combustion kinetics, have not been investigated in-depth. Thus far, most studies have focused on the effects of engine design, such as injection nozzle locations and cylinder shapes, on power generation and emissions. Most of these studies use existing diesel combustion kinetics.
This is of concern because combustion strategies that are currently being developed are more based on fuel properties than combustion patterns with regard to the engine design. There are biodiesels manufactured from soybean, animal fats, waste oils, and algae. Depending on the applications, some biodiesels are blended with diesel 0, 10, 20, 50, 80, or 100%. Due to these variations, biodiesel combustion mechanisms and emissions vary. Accordingly, the engine design and operation conditions must be adjusted to optimize engine performance and to reduce harmful emissions. To address these issues, we have studied a few required properties of biodiesel and ULSD (ASTM standards were followed), fundamental combustion chemistry of biodiesel and basic emission generation models that provide a better understanding of biodiesel combustion characteristics and help to develop more realistic emission generation models.
This study focused first on particulate matter (PM) and then on NOx (NOx =NO+NO2) released during combustion. Because, in general, biodiesel produces more NOx than diesel, its production mechanisms should be more deeply investigated for better pollution control. Furthermore, even if biodieselís PM emission is lower than diesel, its formation mechanisms must be better understood to reduce it without compromising engine performance. Biodiesels with various compositions and feedstock resources were first chemically analyzed for their chemical characteristics. The major components were identified and are then used for the combustion mechanism study. A high-pressure, high-temperature combustion chamber is used at controlled temperature and pressure, and Gas Chromatograph (GC) was used to analyze the emission gases. On the other hand, we tried to relate the examined biodiesel properties to the combustion behavior and PM release.
The proposed experimental research is unique because it is oriented towards fundamental chemical reactions. We looked into a simplified combustion reaction model that describes the reaction mechanisms of biodieselís major components that lead to specific emission species. The results are correlated to biodiesel source feedstock type, engine temperature, and pressure to specific components in the emissions.
The combustion characteristics and models obtained in this study will help develop a robust and realistic biodiesel combustion model.
K. K Shandilya and A. Kumar, Particulate Emissions from Tailpipe during idling of Public Transit Buses Fueled with Alternative Fuels, Environmental Progress & Sustainable Energy, DOI: 10.1002/ep.11696, 201 . (partial work was done under the grant)
K. Shandilya, A. Kumar, Carbon speciation of exhaust particulate matter of public transit buses running on alternative fuels, Fuel 114 (2014) 678Ė684. (partial work was done under the grant)
H. Omidvarborna, A. Kumar, D.S. Kim, P.K.P. Venkata, V.S.P. Bollineni, Characterization and Exhaust Emission Analysis of Biodiesel in Different Temperature and Pressure: Laboratory Study, Journal of Hazardous, Toxic, and Radioactive Waste, May, http://dx.doi.org/10.1061/(ASCE)HZ.2153-5515.0000237 , 2014 (published online by ASCE).
H. Omidvarborna, A. Kumar, D.S. Kim, Characterization of particulate matter emitted from transit buses fueled with B20 in idle modes, submitted to Journal of Environmental Chemical Engineering, March 2014 (in review).
S.K. Kuppili, A. Kumar, D.S. Kim, Biodiesel properties depending on various feedstocks and blends: cloud point, kinematic viscosity and flash point, submitted to Fuel Processing Journal, June 2014 (in review).
H. Omidvarborna, A. Kumar, D.S. Kim, K. K. Shandilya, Analysis of Particulate Matter from the Exhaust of Biodiesel Transit Buses under Idling Conditions (Paper #13431), Proceedings of A&WMA Conference, Chicago, June 2013.
S.K. Kuppili, D.S. Kim, A. Kumar, A Review of Patents on the Production of Biofuels, USA, Student Poster #22, 106th AWMA Annual Conference, Chicago, Illinois, 2013.
H. Omidvarborna, A. Kumar, D.S. Kim, Analysis of Particulate Matter (PM) from the Exhaust of Biodiesel Transit Buses under Idling Conditions, (Paper #31870), Presented as Student Poster at A&WMA Conference, Long Beach, CA, June 2014.
H. Omidvarborna, A. Kumar, D.S. Kim, Experimental Evaluation of a Biodiesel Combustion Model using a Laboratory Reactor, (Paper #31867), Presented as Technical Poster at A&WMA Conference, Long Beach, CA, June 2014.
S.K. Kuppili, D.S. Kim, A. Kumar, Biodiesel Properties Depending on Blends and Feedstocks: Cloud point, kinematic viscosity and flash point, (Paper #33261), Presented as Technical Poster at A&WMA Conference, Long Beach, CA, June 2014.
H. Omidvarborna, D. S. Kim, A. Kumar, K. K. Shandilya, A Field Study to Collect Particulate Matter from the Exhaust of Biodiesel Transit Buses, Poster at Sustainable U 2013 conference, The University of Toledo, 2012.
Kumar, A., Indoor Air Quality (IAQ): Monitoring, Modeling, and Assessment, UT-EAD Research Workshop, Abu Dhabi (UAE), January 22, 2013. This presentation included slides from the biodiesel projects funded by USDOT.
Kumar, A. and Kadiyala, A., An Overview of Ongoing APRG Research Projects at UT, Presentation to UG Students at Mangalayatan University, Aligarh (India), January 23, 2013. This presentation includes slides from biodiesel project.
Kumar, A., Kim, D.S., and Omidvarborna, H., Characterization of Exhaust Particulate Matter from Transit Buses in Toledo, Ohio, Environmental Seminar, Dept. of Civil Engineering, Aligarh Muslim University, January 24, 2013.
Omidvarbona, H., Kumar, A., Kim, D.S., Characterization of Exhaust Emissions From Transit Buses (Brief Review), Air Pollution Course (CIVE 3620) Presentation, The University of Toledo, Toledo, OH, January 28, 2013.
Omidvarbona, H., Kumar, A., Kim, D.S., Characterization of Exhaust Particulate Matter from Transit Buses in Toledo, OH, April 22, 2013 (Chinese Delegation Presentation)
Chinese Delegation Lab Presentation, NE #2022, The University of Toledo, OH, April 25, 2013.
Mineta National Transit Research Consortium (MNTRC) Newsletter Story in April 2013.
Mineta National Transit Research Consortium (MNTRC) Newsletter Story in August 2013.
Mineta National Transit Research Consortium (MNTRC) Newsletter Story in December 2013.
K.K. Shandilya, Characterization, Speciation, and Source Apportionment of Particles inside and from the Exhaust of Public Transit Buses Fueled With Alternative Fuels, PhD Dissertation, University of Toledo, 2012. The dissertation includes initial analysis of combustion related data on B20 completed under this grant.