Quantitative analysis of mass and energy flow in rice straw gasification based on mass and carbon balance

There have been some pilot-scale trials of the fluidized bed and its derivatives for rice and wheat straw gasification in China. Before the industrial promotion, the quantitative data is imperative in preliminary engineering and optimization. A series of experiments were performed on a bench-scale fluidized bed gasifier to obtain data in process in different heat exchange situations. The uncertainty was evaluated and the balance of carbon and mass was performed to verify the quantitative data. Based on the experimental results, the mass and energy flows were established and illustrated in Sankey diagrams. The results show that, as temperature improves from 650 °C to 800 °C, the energy proportion of gas climbs from 27.2 to 64%. When the equivalence ratio decreases, although the calorific value of gas increases from 2.7 to 4.2 MJ/Nm3, the energy proportion of gas does not change much because the gas yield decreases. Finally, the heat exchange, temperature and ER were coupled by interpolation and illustrated in a contour map.