摘要
以新疆润北煤为研究对象,在小型鼓泡流化床上开展了热解实验,结合气相色谱、SEM等表征手段对热解产物及其特性进行了分析,考察了以半焦为热载体不同热解温度条件下CH4和CO2气氛对煤炭流化床热解特性的影响。结果表明:由于煤半焦促进了CH4和CO2的重整反应,CH4/CO2混合气氛下热解产气率与单一气氛相比有所减少,减少幅度随温度和CO2体积分数提高而增加;同时,热解温度为600℃以上时,CO和H2产率随着CO2体积分数的提高和温度的升高而明显增加,相应的热解水产率也明显增加;随着温度升高,受CH4裂解、CH4与CO2重整及CO2与碳的气化等反应的影响,CH4/CO2混合气氛下焦油产率有所增加,在热解温度600℃左右时焦油产率最高的同时增加幅度也较大;受CH4裂解反应积碳以及CO2和半焦的气化反应等过程的影响,CH4气氛下半焦产率增加,CO2气氛下半焦产率降低;CH4/CO2混合气氛下半焦产率及特性同样有明显的变化,且随热解温度升高变化更大;较低体积分数CO2(6%)时,CO2促进CH4裂解积碳,其影响大于CO2与碳的气化反应,半焦产率提高且半焦孔隙变小,表面变粗糙;而随着CO2体积分数提高时(增加到15%),CO2与碳的气化作用增强,使得半焦产率反而明显减少且孔隙变大。
The pyrolysis of Xinjiang Runbei coal were carried out on a small bubbling fluidized bed and the products were characterized by different methods,such as gas chromatography and SEM,to investigate the effects of CH4 and CO2 atmosphere on the pyrolysis characteristics of coal with semi-coke as the heat carrier.The results show that,compared with the single atmosphere,the gas product yield in the CH4/CO2 atmosphere reduced,which was contributed to the promoted reforming reaction between CH4 and CO2 by coal semi-coke.The decreasing degree increased with the temperature and CO2 concentration.When the pyrolysis temperature reached above 600 ℃,the yields of CO,H2 and pyrolysis water significantly increased with the CO2 concentration and temperature.The tar yield increased with the temperature in the CH4/CO2 atmosphere,due to the reactions of methane cracking,methane/carbon dioxide reformation,and carbon dioxide/carbon gasification.The tar yield reached its maximum,and achieved a large increase at about 600 ℃.Owing to the influence of some reactions,such as methane cracking reaction and carbon dioxide and semi-coke gasification,the yield of semi-coke increased in CH4 atmosphere but decreased in CO2 atmosphere.In the CH4/CO2 atmosphere,the yield and characteristics of semi-coke also exhibited distinct changes,which was more obvious with the increase of pyrolysis temperature.At low CO2 concentrations(6%),CO2 promoted the cracking of CH4 more than the gasification of CO2 and carbon.Therefore,the yield of semi-coke increased and the semi-coke had smaller porosity and rougher surface.As the CO2 concentration was increased to 15%,the gasification reaction of CO2 and carbon was enhanced,which caused obvious reduction in semi-coke’s yield and increase in its porosity.
作者
王远丽
王勤辉
李开坤
张瑞月
余春江
方梦祥
WANG Yuanli;WANG Qinhui;LI Kaikun;ZHANG Ruiyue;YU Chunjiang;FANG Mengxiang(State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China)
出处
《热力发电》
CAS
北大核心
2020年第6期7-14,共8页
Thermal Power Generation
基金
国家重点研发计划项目(2017YFB0602800-01)
山西省科技重大专项项目(20181101005)。
关键词
半焦热载体
流化床
热解
气氛
反应
低阶煤
semi-coke heat carrier
fluidized bed
pyrolysis
atmosphere
reaction
low-order coal
