添加CaO对煤热解行为影响的实验研究

Effects of CaO-based additives on the behavior of bituminous coal pyrolysis

为研究高钙碳摩尔比对煤热解过程的影响特性,基于热重红外联用系统与固定床实验系统对宁夏烟煤开展了添加CaO吸收剂的煤热解实验。实验采用钙碳摩尔比分别为0,0.25,0.5与1,结果表明:CaO可显著改变煤失重及气态产物析出历程,添加CaO的热解DTG曲线在400℃与650℃存在失重峰,分别对应CaO水合产物Ca(OH)_2与碳酸化产物CaCO_3分解。此外CaO加入亦降低固态热解产物收率,同时促进热解过程CO,CH_4,H_2产出,并显著改变CO_2析出历程,当钙碳摩尔比由0增至1时,H_2产出增加5.21%,CO产出增加44.13%,CO_2降低17.80%,促进与抑制效果均与钙碳摩尔比成正比。

In oder to investigate the influnces of CaO on the behavior of coal pyrolysis,experiments on the coal/CaO co-pyrolysis were conducted by TG-FTIR system and fixed bed reactor with Ca/C mole ratio of 0,0.25,0.5 and 1.0.The results indicate that coal pyrolysis process is affected remarkably by the additive CaO.By comparing with pure coal pyrolysis,there are two additional weight loss peaks in the DTG profiles of pyrolysis with CaO addition,which correspond to the decomposion of Ca(OH)2 and CaCO 3 respectively.The yield of solid product and CO 2 is inhibited.Meanwhile the yields of CO,H 2,CH 4 is enhanced by CaO.The release process of CO 2 duiring pyrolysis is also changed remarkably.With the Ca/C mole ratio increases from 0 to 1,the yields of H 2 and CO are improved by 5.21%and 44.13%respectively,and the CO 2 release is lowered by 17.8%.The promoiton and inhibition effects are both positively related to the Ca/C mole ratio.