工业废碱液催化煤焦加压水蒸气气化反应的研究

Catalytic effects of industrial waste alkali liquor in pressurized steam gasification of coal char

为了研究工业废碱液对煤水蒸气反应的催化作用,选取内蒙古王家塔煤(WJT),负载造纸黑液(BL)进行高压水蒸气气化性能评价。分别考察了温度和负载量对催化活性的影响,并与分析纯碳酸钠(SC)催化活性进行对比。固定床小试评价结果表明,700−750℃,催化剂活性随负载量增加呈先增大后减小的趋势,BL最佳负载量为3%Na,并且催化活性优于SC催化剂;温度升高,催化活性更显著。采用N2吸附-脱附等温实验考察BL对煤焦比表面积和孔结构的影响,结果表明,随着BL负载量增加到3%,煤焦比表面积和孔容都增加,从而有利于提供更多的气化活性位点,提高煤焦反应活性;随着负载量的进一步增加,催化剂过量造成堆积堵孔,导致催化剂的比表面积和孔容降低,从而降低了气化反应速率。

The catalytic activity of an industrial waste alkali liquor for coal gasification was identified,and the WJT coal impregnated of black liquor(BL)was gasified with steam under the temperatures 700−750℃at high pressure.The effects of major process variables such as catalyst loading and temperature were investigated,which was also in comparison with Na2CO3(SC).The results show that with an increase in the catalyst loading the gasification rate and the carbon conversion rise first and then drop,having the highest values at a 3%of Na loading and being higher than that with SC.Meanwhile,the catalytic activity increases with increasing the gasification temperature.The influence of BL addition on the BET surface area and pore volume was studied by an isothermal N2 adsorption-desorption experiment.It is indicated that the BET surface area and pore volume increase at first and then decrease with an increase in the BL loading.The increase of surface area and pore volume provide more gasification active sites and thus promote the reactivity of char gasification.However,the blocking of pores in coal char caused by excess catalyst loading can result in a decrease in the surface area and pore volume and thus the declining of the gasification rate.