生物质灰对煤焦加氢气化的催化作用

Catalytic effect of biomass ash on the hydrogasification of coal char

以小麦秸秆、马尾藻和山苦荬等三种富含碱金属和碱土金属的生物质为原料,研究了在500、600和815℃下制得的生物质灰对神府煤焦加氢气化的催化作用。结果表明,随着制灰温度由500℃升高至815℃,灰产量减少,且灰中的碱金属和氯元素的含量降低;当制灰温度达到815℃,生物质灰出现明显的熔融现象;600℃灰样对神府煤焦加氢气化具有较好的催化作用,催化效果随灰样添加比例增大而增强。山苦荬灰催化作用较好,而马尾藻灰催化作用较弱。小麦秸秆灰中较高的硅含量和马尾藻灰中较高的氯含量是其催化作用较弱的主要原因;氯元素会加剧碱金属的挥发,弱化与其结合的碱金属的催化效果,对碱金属催化所产生的抑制作用比相同摩尔数的硅更加明显。

Biomass ashes were prepared from three rich in alkaline and alkaline earth metal materials,viz.,wheat straw（WS）,sea grape（SG） and ixeris chinensis（IC）,at different temperatures of 500,600 and 815℃;the catalytic effect of biomass ash on the hydro-gasification of Shenfu coal（SF） char was then investigated.The results show that the ash yield and the content of alkali metals and chlorine reduce with increasing ashing temperature from 500 to 815℃;significant ash melting can be observed at high temperature near 815℃.The biomass ashes obtained at 600℃ exhibits the best catalytic effect on the gasification of coal char;the more the ash is loaded with the char,the stronger exhibit the promoting effect on the gasification is.The ash from IC performs best in catalyzing the coal char gasification,whereas the SG ash is the worst catalyst.The high content of silica in the WS ash and the high content of chlorine in the SG ash may explain their poor catalytic effect on the char gasification;chlorine can aggravate the volatilization of alkali metal and lead to a severer inhibiting effect on the coal char hydrogasification than silica with the same molar quantity.