Introducing a novel reactor concept: Indirectly fired integrated gasification and steam generation system

This paper introduces a novel gasification reactor that uses steam gasification of carbonaceous feedstock by indirectly heating the reacting flow through a high temperature heat exchanger without the need for partial combustion with oxygen. It demonstrates the importance of gasification as a method for increasing power plant efficiency and reducing emissions. This paper also describes the computational model created to model this novel gasifier and the results of the model that illustrates the efficiency and purity advantages of the new gasifier. The reactor was modeled as a 1D counter-reacting flows heat exchanger, using the effectiveness-number of transfer units (ε-N _tu) method. The heating flow was assumed to be fully combusted at the inlet. The gasification stream was modeled as a plug flow, where the reaction is kinetically controlled. A simplified version of the Random Pore Model (RPM) was used to predict the char consumption. The results indicate that the gasification of coal with steam without partial combustion with oxygen using this new concept is feasible. The gasification reaction rates are found to be slow at temperatures less than 1200°C, but most of the char conversion, which reached about almost 100% completion, occurred at higher than 1200°C.