循环流化床生物质催化气化试验研究

Experimental Study on Biomass Catalytic Gasification in Circulating Fluidized Bed

为研究不同催化剂、不同当量比及不同温度条件下生物质气化效果,采用1.5 MW、产气率4500m^3/h循环流化床试验平台,分别对木屑和稻壳两种生物质原料的催化气化特性进行试验研究。试验结果表明:对于同一种生物质原料,采用橄榄石作为催化剂时,其气化气体中的可燃成分含量更高,橄榄石催化效果优于白云石和菱镁矿;而与稻壳相比,木屑气化产出生物质气体中的可燃成分比重更高;随着当量比的增加,气体热值均有所下降,其原因是当量比增大导致了空气中的氮气更多的进入气化炉,稀释了气化气的体积浓度,从而使得气体热值明显下降。在当量比ER为0.1和0.2条件下,采用橄榄石作为催化剂可以得到热值较高的生物质气;三种催化剂的最佳催化反应温度均为750℃左右,ER=0.2时的气体产率明显比ER=0.1高,说明更多的空气进入气化炉参与反应,产品气体积有所增加,但是将降低气体热值。

In order to study the effect of biomass gasification under different catalysts,different equivalent ratios and different temperature conditions,the catalytic gasification characteristics of wood chips and rice shell were tested by using a test platform of 1.5 MW and gas production rate of 4500 m^3/h circulating fluidization.The test results showed that,when olivine was used as catalyst for the same biomass raw material,the combustible content of gasified gas was higher,its catalysis effect was better than the dolomite and magnesia;Compared with the rice shell,the proportion of combustible components in the biomass gas produced by wood chip gasification was higher;And the thermal value of gas decreased with the increase of the equivalent ratio.The reason was that the increase of the equivalent level led to more nitrogen in the air into the gasified furnace,diluting the volume concentration of gasified gas,thus making the gas thermal value significantly decrease.Under the condition of 0.1 and 0.2 equivalent ratio of ER,the biomass gas with higher thermal value was obtained by using olivine as a catalyst,the optimum catalytic reaction temperature of the three catalysts was about 750℃,and the gas yield at ER=0.2 was significantly higher than that of ER=0.1,indicating that more air entered the gasification furnace to participate in the reaction,the volume of produced gas increased,but the calorific value of the gas decreased.