Performance, emission and net energy analysis of a diesel genset using producer gas from jatropha press-cake in dual fuel miode

The by-product of Jatropha biodiesel production which is Jatropha press-cake has a potential to be used as a direct feedstock in a gasification process. A throatless downdraft gasifier had been used to convert the press-cakes into producer gas. This study focus on the use of producer gas derived from Jatropha press-cake as an alternative fuel in a diesel genset in dual fuel mode operation. The emission and performance were investigated through a combination of parameter settings at diesel injection timing of 6, 9, and 12 degrees BTDC, gas flowrates of 0, 10, and 20 kg/h, and electrical load of 1, 1.5 and 2 kW. Genset performance were defined according to diesel consumption rate (DCR), equivalence ratio (ER), specific fuel consumption (SFC), thermal efficiency (TE), and exhaust gas temperature. In general, performance was found to be lower in dual fuel mode operation than running the engine in diesel only. This was due to the low calorific value of the producer gas which is equal to 4.702 MJ/kg as analyzed by CRL corp. Also, the emission level for HC, CO, CO2, and NOx were higher for dual fuel operation. Individual and overall optimization had been implemented using response surface methodology, central composite design. A comparison of net energy analysis of Jatropha biodiesel production coupled with press-cake gasification and direct gasification of Jatropha seed from the result of previous study shows that NEB and NER were higher for biodiesel and producer gas derived from press-cake

Optimization of diesel injection timing, producer gas flow rate, and engine load for a diesel engine operated on dual fuel mode at a high engine speed

Jatropha seed cake is a byproduct of biodiesel production, and the seed cake can be used as a feedstock for a gasifier. The gasified seed cake can partially reduce fossil diesel consumption to run a diesel engine. However, an increase in gas flow rate is associated with a higher diesel substitution rate, but a higher specific CO2 emission is observed. This study attempts to optimize diesel injection timing (DIT), gaseous fuel flow rate, and engine load to offset the specific diesel consumption and the specific CO2 emissions at a high engine speed of 3,000 rpm. Response Surface Methodology (RSM) was applied to statistically develop mathematical models of the response variables as functions of the design variables. A desirability function was then applied to maximize overall desirability. It highlighted that an overall desirability of 0.829 was obtained at 11° before top dead center (BTDC) of the DIT, a 10 kg/h gas flow rate, and 70% of the full engine load. At the optimum operating settings, the specific diesel consumption (SDC) and the specific CO2 emission were 0.0967 kg/kWh and 0.6123 kg/kWh, respectively. A value of electrical-thermal efficiency was found to be 14.10%. It is evident from these findings that a dual producer gas-diesel fuel engine should not be operated at the maximum diesel replacement rate. © 2019, Paulus Editora. All rights reserved

The effect of jatropha seed cake producer gas flow rates on a diesel engine operated on dual fuel mode at high engine speed

© 2019, Paulus Editora. All rights reserved. Jatropha seed cake is a byproduct of biodiesel production. The seed cake can be used to make a producer gas that can be fumigated into a diesel engine operated on dual fuel mode without major modification. This paper intends to investigate the impact of Jatropha seed cake-derived producer gas mass flow rate on the performance and emission characteristics of a diesel engine operated on a dual fuel mode at a high engine speed of 3,000 rpm. The results highlight that the maximum diesel replacement rate reached 60% at a 20 kg/h gas flow rate when the engine was operated at medium engine load. An increase in gas flow rate augments the diesel substitution rate but decreases the electrical-thermal efficiency (ETE). At 70% of the full engine load, the specific diesel consumption declined from 0.337 to 0.185 kg/kWh when the gas was increased from zero to 20 kg/h. At this engine load, the ETE sharply fell off from 25% to 10.6% and 6.6% when the gas flow rate increased from zero to 10 kg/h and 20 kg/h, respectively. The electrical specific fuel consumption and electrical specific energy consumption, exhaust hydrocarbon (HC), carbon monoxide (CO), and carbon dioxide (CO2) emissions were found to be higher with an increase in gas flow rate. Unlike dual fuel engine operation at medium speed, the nitrogen oxides (NOX) emissions were consistent with an increase in gas flow rate. Based on the empirical findings, the dual producer gas-diesel engine should be operated at high engine load but not at a high engine speed of 3,000 rpm with a maximum gas flow rate of 20 kg/h