Design and Development of Downdraft Gasifier to Generate Producer Gas

Utilization of waste is the need of hour today. The waste which cannot be degraded by bio-chemical route like agricultural waste, wood waste can be converted into useful fuel through the process called Gasification. Gasification is a thermo-chemical process which converts solid biomass into a mixture of combustible gases that can be used in various applications. In this project, a prototype of downdraft gasifier is designed and developed of 20 KWthcapacity for generating producer gas for fulfilling heating requirement of a heat treatment furnace. Wood blocks of varying sizes are used as a feed stock in the gasifier. The performance characteristics of the gasifier are studied at different air flow rates. A reduction in the overall cost for replacing fuel oil and LPG is estimated. Performance of gasifier with other feed stocks such as agricultural waste briquettes is checked and their results are compared. It is found that wood block of size less than 50 mm has higher calorific value of 3.978 MJ/Nm3 and when coconut shells are mixed with wood, the calorific value obtained is highest i.e. 4.865 MJ/Nm3.