干馏炉内水蒸气对兰炭热解过程中硫迁移的影响  

Effect of water vapor on sulfur migration during pyrolysis of semi-coke in oven for dry distillation

作　　者：折媛[1] 尤宽 巨建涛[1] 刘诗薇[1] 邹冲[1] 徐玉芬 SHE Yuan;YOU Kuan;JU Jiantao;LIU Shiwei;ZOU Chong;XU Yufen(School of Metallurgical Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,Shaanxi,China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710055

出　　处：《钢铁》2023年第8期51-60,共10页Iron and Steel

基　　金：国家自然科学基金资助项目(51904223)。

摘　　要：用于冶金生产的兰炭会在干馏炉内受到回炉煤气燃烧和湿熄焦产生的水蒸气的影响。为明确水蒸气对兰炭孔隙结构及硫含量的影响,选取某低阶煤在不同热解条件下进行热解试验,考察不同热解终温(500~900℃)和水蒸气通入量(质量分数为0、20%、40%、60%)对低阶煤热解产物中硫含量的影响。采用比表面及孔径分析仪和定硫仪分析了兰炭孔隙结构及兰炭中全硫相对含量的变化,采用X射线光电子能谱对兰炭表面含硫官能团的赋存形态进行了分析。试验结果表明,在惰性气氛下,当温度成为限制性环节时,中低温(500~700℃)条件下硫的脱除效果较好,热解终温进一步升高则不利于硫的脱除。当在热解过程中通入水蒸气时,低温条件下(500~600℃),少量(20%)水蒸气脱硫显著,大量(40%~60%)水蒸气则不利于脱硫,此时不同形式的硫会出现相互转化的情况,水蒸气促使硫主要以气相形式析出。较高温度条件下(700~800℃)水蒸气虽促进孔隙结构发育,但硫无法以气相形式析出,水蒸气和缩聚反应共同作用下使硫主要在固相中进行转化,从而导致脱硫率降低。高温条件下(900℃)水蒸气对孔隙结构破坏严重,使硫主要以气相形式析出,显著提高脱硫率,但会生成部分无机硫和较难分解的有机硫。因此,在干馏炉生产兰炭的过程中,应严格控制中高温区域生产流程,避免水蒸气的进入,在低温区域的水蒸气添加量也应尽量控制在20%以内。The semi-coke used in metallurgical production will be affected by the water vapor generated by wet coke quenching and the combustion of returned furnace gas in the oven for dry distillation.In order to clarify the effect of water vapor on the pore structure and sulfur content of semi-coke,a low-rank coal was selected for pyrolysis experiments under different pyrolysis conditions,the effects of different final pyrolysis temperatures(500-900℃)and water vapor input rates(0,20%,40%,60%)on the sulfur content in low-rank coal pyrolysis products were investigated.The change of pore structure and total sulfur relative content of semi-coke was analyzed by specific surface and pore size analyzer and sulfur determination instrument,and the occurrence form of sulfur-containing functional groups on the surface of semi-coke was analyzed by X-ray photoelectron spectroscopy.The experimental results showed that in an inert atmosphere,when the temperature becomes the limiting link,the sulfur removal effect is better at medium and low temperatures(500-700℃),and the further increase of the final pyrolysis temperature is not conducive to the sulfur removal.When water vapor is introduced into the pyrolysis process,at low temperature(500-600℃),a small amount(20%)of water vapor desulfurization is significant,and a large amount(40%-60%)of water vapor is not conducive to desulfurization.At this time,different forms of sulfur will be transformed into each other,and water vapor promotes sulfur to precipitate mainly in the form of gas phase.Under higher temperature conditions(700-800℃),although water vapor promotes the development of pore structure,sulfur cannot be precipitated in the form of gas phase.Under the combined action of water vapor and polycondensation,sulfur is mainly converted in the solid phase,resulting in a decrease in desulfurization rate.Under the condition of high tem perature(900℃),water vapor seriously destroys the pore structure and makes sulfur mainly precipitate in the form of gas phase,which significantly

关 键 词：兰炭 热解 水蒸气 硫形态 脱硫率 X射线光电子能谱 

分 类 号：TQ530.2[化学工程—煤化学工程]