Abstract:
The partial combustion of waste water sludge in the gasifier generates producer gas used for heating purposes and as supplementary or sole fuel in the internal combustion engines. In this study, the waste water sludge is used as the feedstock for down-draft gasifier to produce the producer gas to run in diesel engine for power generation. The engine used is a dual-fuel engine where producer gas and air are mixed at the air intake duct and the combustion of air-fuel mixture occurs after the ignition of diesel. Because of the longer ignition delays and slower burning rate of producer gas, the effect of advanced injection timing on the performance has been examined. The engine has standard injection timing of 12 before TDC. The injection timing was advanced by 4 given injection timing of 16 BTDC. The objective is to compare between the standard and advanced injection timing dual-fuel mode and with that of pure diesel. The system was experimentally optimized with respect to maximum diesel saving and lower emission in dual-fuel mode operation. As the result of standard and advanced injection timing in dual-fuel mode, the maximum diesel replacement rate was 77 percent at 36 percent load engine in dual-fuel with advanced injection timing. From the specific energy consumption and the brake thermal efficiency of the engine of dual-fuel with advanced injection timing was slightly different from standard injection timing. The reduction of CO emission and increasing of Coz emission in dual-fuel mode was the effect of advanced injection timing. This is due to the better combustion efficiency of the system compared to that of standard injection timing. NOx emission of dual-fuel mode with standard injection timing was lower than advanced injection timing as a result of decreasing of Nitrogen in air. The exhaust gas temperature of the engine varies on load. The smoke opacity of advanced injection timing was lower than standard injection timing because of the longer time for combustion and lower diesel consumption. At the high load, the opacity of diesel was lower than dual-fuel mode due to the decreasing of air in chamber which is the cause of incomplete combustion due to fuel lean mixture.