STUDY OF EXIT GAS COMPOSITION IN A BUBBLING FLUIDIZED BED COMBUSTOR USING RICE HUSK

摘要

With growing population and depletion of fossil fuels, there is an urgent need to effectively tap the non-conventional and renewable energy sources. Among the various alternatives, biomass holds a special promise particularly in an agricultural country like India. Rice-husk is one biomass resource that, with the help of fluidized bed combustion can be efficiently converted into thermal energy and used for power generation. The concept of generating energy from rice husk has great potential as it not just acts as a solution to the problem of depleting fuels, but also helps in solving disposal problems. In the present work, a three phase model for exit gas composition of a commercially operated bubbling fluidized bed, located in Amritsar, in which rice husk is being used as feed has been developed. The fluidized bed has been assumed to be composed of a number of equivalent stages in series. Within each stage, exchange of gas takes place between the bubble, cloud-wake and emulsion phases. Physico-chemical parameters like minimum fluidization velocity, operating velocity, bubble properties, etc. have been found. Exit gas composition predicted by the model has been compared with plant data and reasonable agreement is obtained. Effect of fuel composition and excess air on exit gas composition and physico-chemical parameters were studied.