Experimental Investigation of Biomass Gasification in a Fluidized Bed Reactor

Abstract

This paper aims to catch the influence of various operating conditions and catalyst addition on the property of gas product and tar evolution. The gasification of three local biomass samples (sawdust, peanut shell, and wheat straw) was performed using a fluidized bed gasification reactor, and the gas product and liquid tar were analyzed with gas chromatography (GC). First, the influence of biomass property, gasification temperature, and air equivalence ratio was investigated. The biomass feeding rate was set at ∼2.37 kg/h; the furnace temperature variant was between 750 and 850 °C; and the equivalence ratio (ER) was 0.15−0.35. It can be observed that a lower heating value (LHV) of gas product from sawdust is higher than peanut shell and straw, while the tar content is also much higher than the other two samples, which might be attributed to the high volatile content. At 800 °C, with the increase of ER, the gas yield increased rapidly from 1.14 to 1.93 m3/kg, while the LHV decreased from 7.09 to 3.26 MJ/m3. Meanwhile, the variation of ER also showed a great effect on tar species. With the increase in temperature, combustible gas content, gas yield, and LHV all increased significantly, while the tar content decreased sharply from 13.24 to 6.53 g/m3, which indicated that high temperature was favorable for biomass gasification. Then, three additives (dolomite, magnesite, and olivine) were introduced into the gasification process as catalyst for tar cracking. It is great for the upgrading of gas product quality, and tar removal efficiencies are all above 50%. It is significant for the development of biomass gasification technology.