高碱煤液态排渣燃烧条件下碱金属释放特性研究  

Study on Akali Release Characteristics During the Slag Tapping Combustion of High-Alkali Coal

作　　者：胡兴雷 李丹 张海东 张忠孝[1] 樊俊杰[3] 周昊[2] 范浩杰[1] 李子祥 乌晓江[1] HU Xinglei;LI Dan;ZHANG Haidong;ZHANG Zhongxiao;FAN Junjie;ZHOU Hao;FAN Haojie;LI Zixiang;WU Xiaojiang(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Tianjin HuaNeng Yangliuqing Power Co.,Ltd.,Tianjin 300380,China;School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海交通大学机械与动力工程学院,上海200240 [2]天津华能杨柳青热电有限责任公司,天津300380 [3]上海理工大学环境与建筑学院,上海200093

出　　处：《锅炉技术》2023年第4期30-39,共10页Boiler Technology

基　　金：国家自然科学基金计划项目(52176121);国家重点专项课题资助课题(2018YFB0604102);上海市优秀技术带头人项目(19XD1431000)。

摘　　要：采用液态排渣旋风燃烧技术可优先将煤中Na等碱金属以硅铝酸盐熔渣的形式从炉底排出,从而有效减缓燃高碱煤锅炉尾部受热面的强沾污、结渣问题。高温液态排渣燃烧条件下Na的迁移、释放特性对其在炉内渣膜的捕捉行为影响巨大。为此,在沉降炉上研究了3种典型高碱煤(地表高氯煤、将军庙煤、沙尔湖煤)在液态排渣高温热解—燃烧过程中,煤中Na的释放特性以及Ca、Fe等对Na释放行为的影响。研究结果表明:热解阶段,水溶性Na主要以Na2SO4、NaCl等形式释放,1500℃下释放率为63.1%~68.6%;酸溶性Na主要通过分解或与自由基反应释放,1500℃下释放率为64.4%~79.2%;高温下,部分水溶性Na、酸溶性Na会与灰中硅铝酸盐矿物反应转化为不可溶性Na。Ca、Fe在热解阶段对Na的释放影响并不显著;焦炭燃烧阶段,水溶性Na和酸溶性Na的释放率达95%以上,灰中不溶性Na分别为3种原煤中不溶性Na的2.64倍、2.28倍和5.6倍,表明高温液态排渣燃烧条件下,高温熔渣对Na具有一定的捕捉作用,且以不可溶性Na的形式固化于高温熔渣当中。Cyclone-fired combustion technology has advantages in solving the problem of strong fouling and slagging of high alkali coal by discharging Na and other alkali metals from the furnace bottom in the form of aluminosilicate slag.The transfer and release characteristics of Na in high temperature combustion have great influence on its capture behavior in the furnace.In this paper,the release of alkali metal Na from three typical high alkali coals(DB coal,JJM coal and SEH coal)during pyrolysis-combustion at high temperatures and the effect of the release of Ca and Fe on the release of Na were systematically studied in a drop furnace.The results show that in the pyrolysis stage,water-soluble Na is released in the form of Na 2 SO 4,NaCl and other molecules,and the release rate is 63.1%~68.6%at 1500℃.HCl-soluble Na is released by decomposition or reaction with free radicals,and the release rate is 64.4%~79.2%at 1500℃.Some water-soluble Na and acid soluble Na react with aluminosilicate minerals in ash to convert into insoluble Na.Ca,Fe have no significant effects on Na release during pyrolysis.In the combustion stage,the release rate of water-soluble Na and acid soluble Na is above 95%.Insoluble Na in ash is 2.64 times,2.28 times and 5.6 times higher than that in the three raw coals respectively.It indicats that the high temperature slag has a certain capture effect on Na,and Na is insoluble and exists in the slag under the conalition of high temperature slag tapping.

关 键 词：高碱煤 沾污结渣 液态排渣 碱金属释放 

分 类 号：TQ534[化学工程—煤化学工程]