Experimental Study on Product Gas and Tar Removal in Air-Steam Gasification of Corn Straw in a Bench-Scale Internally Circulating Fluidized Bed

摘要

Excessive consumption of fossil fuels and its negative global effects have resulted in increasing interest in biomass energy. This paper presents an experimental study on biomass gasification reactions in an internally circulating fluidized bed gasifier (ICFBG). This work uses compressed corn straw as the raw material and studies the influence of different factors (temperature, equivalent ratio (ER), catalyst, and S/B ratios) on gasification products, in which S/B ratios are defined as the ratios of the steam rate to the biomass feeding rate. The experimental results show that when the bed material is the coal ash residue and air is used as the gasification agent, an increase in temperature from 700 to 900 degrees C reduces the CO2 and CH4 contents, whereas the H-2 and CO contents increase. When a gasification agent is air-steam and the temperature is maintained at 700 degrees C, with a gradual increase in the amount of steam supplied to the gasifier, the CO2 and H-2 contents gradually increase. Besides, an increase in the temperature, S/B ratio, and mixing proportion of dolomite leads to a gradual decrease in the tar content as well as the proportion of light tar, while the proportion of heavy tar becomes relatively high. In addition, we obtained experimental data for an actual gasifier and conducted a brief comparative analysis with the ICFBG developed in this study. The results show that the data provided by the ICFBG developed in this study can serve as a reference and theoretical basis for the operation of actual gasifiers in power plants.