气流床煤气化炉渣特性及综合利用研究进展

Review on characteristics and utilization of entrained-flow coal gasification residue

我国煤化工技术的快速发展使煤气化炉渣排放量急剧增加。气化炉渣的减量化、资源化、无害化利用已是当前煤化工行业的研究热点。概括了气流床煤气化炉渣的矿物学和物化特性,总结了国内外气化炉渣在建材、污水处理、锅炉掺烧等领域的研究现状,提出了当前气化炉渣利用存在的局限性问题,展望了未来煤气化炉渣利用技术的发展方向。结果表明:气流床煤气化炉渣以无定形物(残碳和玻璃体)为主,少量矿物晶体包括石英、方石英、莫来石、钙长石等;其化学组成主要为SiO_(2)、CaO、Fe_(2)O_(3)、Al_(2)O_(3)等,与煤燃烧后灰化学组成相似,对于液态排渣炉型,由于助溶剂的加入,其CaO质量分数>10%。气化炉渣SiO_(2)、Fe_(2)O_(3)、Al_(2)O_(3)含量低(部分气化渣三者总相对质量分数小于60%),残碳、全水质量分数高(湿排气化细渣残碳高达30%,全水60%)、成分不稳定,是制约其资源化利用的主要因素。气化炉渣的利用存在领域窄、附加值低、产品质量差、掺量少、缺乏相关标准和技术规范等问题。目前,建材化、循环流化床锅炉掺烧是气化炉渣的主要利用途径,烧结陶粒和作为吸附剂处理废气、废水是其高附加值综合利用途径。气化炉渣资源化利用研究应以适合的脱水技术、残碳和灰分的高效分离、残碳与玻璃体的分级利用为突破,应因地制宜,寻求气化炉渣高附加值与大规模消纳相结合、适合市场的综合利用方案。

In accordance with the rapid development of China’s coal to chemical industry,the production of coal gasification residues has accordingly increased dramatically.However,the beneficial utilization of coal gasification slag,either researches or practical applications,is unreasonably limited.It is thus becoming a hot area in the coal to chemical industry to develop the coal gasification residue associated re⁃duction,harmless and reutilization technology.In the present article,the status and progress with respect to entrained-flow coal gasification slag physiochemical properties(mineralogical properties,chemical composition and physical properties),beneficial utilizations as building materials,sewage treatment adsorbents and boiler fuels were presented.The current technical barriers and practical limitations for the utili⁃zation of coal gasification slag were discussed,based on which the future development needs for the utilization technology of coal gasifica⁃tion slag is proposed.According to the analysis,the mineral composition of coal gasification slag is mainly amorphous(residual carbon and vitreous),with a small amount of quartz,cristobalite,mullite,feldspar and other mineral crystals.Its chemical composition is mainly SiO2,CaO,Fe2O3 and Al2O3,this is similar to the chemical composition of ash after coal combustion,the Cao mass fraction of liquid slag dis⁃charge furnace is generally more than 10%due to the addition of cosolvent.The low mass fraction of SiO2,Fe2 O3 and Al2 O3(the total a⁃mount of these three substances in part of gasification slag is less than 60%),high mass fraction of residual carbon and total water(the re⁃sidual carbon of wet exhaust fine slag is as high as 30%and total water is 60%),and unstable composition of gasification slag are the main factors restricting its resource utilization.There are some problems in the utilization of gasifier slag,such as narrow field,low added value,poor product quality,small dosage,lack of relevant standards and technical specifications.Building materials and mixed combustion of cir⁃culating fluidized bed boilers are the main utilization ways at present,sintered ceramsite and its use as adsorbent to treat waste gas and wastewater are one of the ways of comprehensive utilization with high added value.The research on resource utilization of gasifier slag should be based on the suitable dehydration technology,efficient separation of residual carbon and ash,and graded utilization of residual carbon and vitreous.It is necessary to seek a comprehensive utilization scheme which combines high added value with large-scale consump⁃tion and is suitable for the market.