Design, Development And Evaluation Of A New Type Of Continuous Downdraft Gasifier To Generate Producer Gas From Rice Husk

Abstract

Rice husk is an important agricultural waste, that  can be converted into useful fuel through the process called gasification. In this technology, the rice husk is transformed into a mixture of combustible gases in a  thermo-chemical process. The producer gas  can be used in various applications such as heating production, internal combustion engine application. In the present work, a new prototype of downdraft gasifier is designed and developed of 10 KWth capacity. Fresh rice husk from rice mill is used as a feed stock in the gasifier. It is equipped of a feed system and a drawer ash discharger, which permit continuous run without perturbation. The producer gas was burnt, in order to heat  an water heater, and to evaluate its performance. The performance characteristics (the output power rate,  the gasifier efficiency, the fuel consumption, conversion rate, calorific value and dynamics behavior) are studied and analyzed at different value of the specific gasification rate. It was found that the best thermal efficiency measured was 34% at specific gasification rate equal to 202 kg/h.m². The maximum power rate was 3800 W  at specific gasification rate equal to 275 kg/h.m², and the minimum fuel consumption was 8,87g/kCal at specific gasification rate equal to 202kg/hm². Experiments showed that higher temperature in the reaction zone increases the performance of the gasifier. However, this temperature should not be greater than 900°C to avoid the ash fuse, which is difficult to remove from the gasifier.