Diesel Engine Particulate and Gaseous Emissions from the Combustion of Microbial Biodiesels

Class

Article

Department

Chemistry and Biochemistry

Faculty Mentor

Lance Seefeldt

Presentation Type

Oral Presentation

Abstract

Challenges associated with feedstock production through lipid recovery has resulted in limited engine testing of microbial based biofuels. This study evaluates the combustion of methyl ester biodiesels produced from a microalgae Nannochloropsis salina, and an oleaginous yeast Cryptococcus curvatus, in a modern compression ignition engine in comparison to methyl ester biodiesel produced from traditional feedstocks. Microbial biomass was converted through in situ transesterification. Methyl esters were then extracted using chloroform which was then distilled off before a final vacuum distillation of the methyl esters to ensure fuel purity. Engine testing was performed to quantify the performance and emissions from combustion of each fuel in a Tier 3, turbocharged, 4-cylinder, 4.5 L John Deere PowerTech Plus common rail, direct injection diesel engine. A direct comparison of the emissions from the microalgae and yeast biodiesels with biodiesel produced from soybean, and canola was performed. Fatty acid profiles were obtained for both the N. salina and C. curvatus methyl esters, the former contained 14.6% C20:5, which prior work has suggested could be problematic from an oxidative stability and ignition quality standpoint. Gaseous emissions measurements included CO, CO2, NOx, CH2O and total hydrocarbons along with total PM mass emissions, particle size measurements and elemental to organic carbon ratio. Despite the high levels of C20:5 in the N. salina methyl -esters, the results indicated that the microalgae based biodiesel performed similarly to biodiesel produced from traditional feedstocks. Specifically, CO and total hydrocarbon emissions were both found to decrease by 20%, and PM emissions decreased by 50% in comparison to certification ULSD. Significantly it was found that the NOx emissions from both the microalgae and yeast based biodiesels were lower than certification ULSD.

Start Date

4-9-2015 12:00 PM

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Apr 9th, 12:00 PM

Diesel Engine Particulate and Gaseous Emissions from the Combustion of Microbial Biodiesels

Challenges associated with feedstock production through lipid recovery has resulted in limited engine testing of microbial based biofuels. This study evaluates the combustion of methyl ester biodiesels produced from a microalgae Nannochloropsis salina, and an oleaginous yeast Cryptococcus curvatus, in a modern compression ignition engine in comparison to methyl ester biodiesel produced from traditional feedstocks. Microbial biomass was converted through in situ transesterification. Methyl esters were then extracted using chloroform which was then distilled off before a final vacuum distillation of the methyl esters to ensure fuel purity. Engine testing was performed to quantify the performance and emissions from combustion of each fuel in a Tier 3, turbocharged, 4-cylinder, 4.5 L John Deere PowerTech Plus common rail, direct injection diesel engine. A direct comparison of the emissions from the microalgae and yeast biodiesels with biodiesel produced from soybean, and canola was performed. Fatty acid profiles were obtained for both the N. salina and C. curvatus methyl esters, the former contained 14.6% C20:5, which prior work has suggested could be problematic from an oxidative stability and ignition quality standpoint. Gaseous emissions measurements included CO, CO2, NOx, CH2O and total hydrocarbons along with total PM mass emissions, particle size measurements and elemental to organic carbon ratio. Despite the high levels of C20:5 in the N. salina methyl -esters, the results indicated that the microalgae based biodiesel performed similarly to biodiesel produced from traditional feedstocks. Specifically, CO and total hydrocarbon emissions were both found to decrease by 20%, and PM emissions decreased by 50% in comparison to certification ULSD. Significantly it was found that the NOx emissions from both the microalgae and yeast based biodiesels were lower than certification ULSD.