黏结煤与不黏煤共热解特性研究

Co-pyrolysis characteristics of caking coal with non-caking coal

为了利用内构件反应器热解技术实现黏结性煤的高值化利用,采用TG-MS和固定床反应器研究了黏结的山西兴县煤(简称XX煤)与不黏的先锋褐煤(简称XF煤)共热解时的破黏和热解特性。TG-MS实验结果表明,XX煤与XF煤配制的混合煤比XX煤黏性小,且XF煤促进了XX煤热解,混合煤热解行为是两种煤共同作用的结果。固定床热解实验表明,煤粒径越小,降黏越显著;XX煤和XF煤的比例(XX:XF)越小,降黏越显著,XX:XF小于5:5时,可消除结焦团块;XX:XF越小,半焦产率越低,焦油和煤气产率越高;随XX:XF减小,焦油中<170℃和230~300℃的馏分含量先升后降,XX:XF=6:4~3:7时最高,170~210℃、210~230℃和300~360℃的馏分逐渐增加,>360℃的馏分含量不断降低;随XX:XF的减小,H_(2)含量先升高后降低,在XX:XF=3:7时最高;CO含量呈略微升高趋势;CO_(2)含量先逐步升高,在XX:XF=6:4达到最高,然后从XX:XF=5:5开始降低,在XX:XF=3:7达到最低,然后又开始升高;CH_(4)及C_(2)~C_(3)组分含量呈下降趋势,而H_(2)+CO+CH_(4)(煤气中有效组分之和)的含量先下降再升高接着再降低,在XX:XF=6:4时最低,XX:XF=3:7时最高。XX:XF越小,虽半焦的C/N和C/H不断减少,但C元素含量增幅和N,H元素含量减幅增大;比表面积越大,内孔结构越多越大,起燃温度越低,燃烧越彻底。

The decaking technology with co-pyrolysis of caking coal and non-caking coal was brought out to destroy the caking property of caking coal.And the properties of decaking and co-pyrolysis of caking coal with the decaking technology were studied with co-pyrolysis experiments using TG-MS and fixed bed pyrolyzer.It could be seen from TG-MS experiments that the caking property of the mixed coal produced by caking coal and non-caking coal was smaller than that of caking coal.And pyrolysis of caking coal can be improved by the addition of non-caking coal.The co-pyrolysis characteristics of the mixed coal were the combined action of those of the two single coals.And it could be seen from the fixed-bed pyrolysis experiment that the decline of caking property of the mixed coal rised with smaller particle size of coal and the descent of the ratio of caking coal to non-caking coal in the mixed coal(XX:XF).And the agglomerate was slight.With the descent of XX:XF,the content of char reduced in pyrolysis products,but the contents of tar,coal gas and carbon deposition and water were higher.With the descent of XX:XF,the fractions of distillation cut<170℃ and 230~300℃ in tar from mixed coal first rise and then decrease and reach peak value at XX:XF=6:4~3:7,and the fractions of distillation cut of 170~210℃,210~230℃,300~360℃ rised,while the fraction of distillation cut>360℃ decreased.With the descent of XX:XF,the contents of H_(2),CO and CO_(2) in coal gas from mixed coal become larger,but the contents of CH_(4) and C_(2)~C_(3) became smaller.While the contents of H_(2)+CO+CH_(4) became first smaller and then larger with XX:XF and reached peak value at XX:XF=5:5~3:7.And with the descent of XX:XF,the char from mixed coal had smaller C/N and C/H,larger amplitudes of increase of C content and reduction of content of N and H,larger special surface area,more and larger internal pore structure,lower ignition temperature,more complete combustion.