摘要
煤气化过程中产生大量含碳量较高的气化细渣,其填埋处理不仅占用大量土地,污染土壤和水体,同时造成能源浪费,如何高效环保地对气化细渣进行资源化利用是目前研究的热点。在获得气化细渣工业分析、元素分析、粒径分布、灰成分和微观形貌等基础上,利用热重对气化细渣单独燃烧及与燃料煤混合燃烧特性进行研究,对比了气化细渣与典型煤种燃烧特性的差异,并考虑掺混比例对混燃的影响。研究结果表明:气化细渣的M_(ar)=69. 7%,A_d=54. 5%,w(C_d)=43. 4%,Q_(gr,d)=16. 14 MJ/kg,干化后的气化细渣中碳含量和发热量与对比劣质烟煤相当;干燥后的气化细渣粒径普遍小于200μm,且孔隙结构发达,电镜结果显示其微观结构由球形颗粒和不规则多孔形状颗粒组成。气化细渣与其他煤种燃烧特性对比表明:气化细渣的着火温度和燃尽温度分别为601. 6℃和680. 8℃,着火和燃尽特性比对比煤样和对应的原煤略差。气化细渣和原煤在不同掺烧比例下的热重燃烧试验结果表明,气化细渣和原煤掺烧存在显著的协同效应,与原煤掺烧能显著改进气化细渣的燃烧特性,在25%气化细渣掺烧比例下,气化细渣的燃烧特性得到显著改善,且相比于纯烧原煤,掺烧气化细渣后混煤的燃烧特性未显著下降。研究结果表明,干化后高含碳量的气化细渣极具应用价值,且与原煤掺烧对混煤的燃烧特性影响较小,还能显著改进混煤的燃烧特性,将干化后的气化细渣与原煤掺烧是一种可行的利用气化细渣热值的技术方案。
In the process of coal gasification,a large amount of fine gasification slag (HC-ash) with high carbon content is produced.The ash-waste landfilling occupies a lot of land,causes the pollution of soil and water,and also wastes the energy.How to utilize the coal-gasification ash (HC-ash) is attracting more and more attentions recently.Based on the proximate and ultimate analysis,particle size distribution,ash compositions,and micro-morphologies of HC-ash,the characteristics of HC-ash combustion alone and combustion with raw coal were studied by thermos gravimetric analysis (TGA).The difference of combustion characteristics between HC-ash and typical coal was compared.The influence of mixing ratio on mixture combustion was also considered.The results show that the moisture of HC-ash (as received basis) reaches 69.7%,the ash of dried HC-ash is 54.5%,the carbon content in dried HC-ash is 43.4% with a heating value of 16.14 MJ/kg.The carbon content and calorific value of dried HC-ash are equivalent to that of inferior bituminous coal.The particle size of dried HC-ash is generally smaller than 200 μm,but with a very developed porous structure.The results of SEM show that the microstructure of HC-ash is composed of sphere and porous irregular shapes.HC-ash compared with other types of combustion characteristics show that the ignition temperature and burnout temperature of HC-ash is 601.6 ℃ and 680.8 ℃,respectively,which are slightly worse than those of contrastive coal samples.The TGA results with different mixing ratio of HC-ash and raw coal show that a significant synergistic effect is observed during the co-combustion of HC-ash and raw coal,which can significantly improve the combustion property of HC-ash.When mixing ratio is 25%,the combustion property of HC-ash is significantly improved and the combustion characteristics of mixed coal with HC-ash decreases slightly compared with pure raw coal.This study indicates that the dried HC-ash is of great application value,its co-firing with raw coal has little influence on the combustion characteristics of mixed coal and is able to improve the overall combustion properties.The overall results suggest that combustion of dried HC-ash with raw coal is a feasible technical scheme to utilize the calorific value of HC-ash.
作者
杜杰
戴高峰
李帅帅
王学斌
孙晓伟
谭厚章
DU Jie;DAI Gaofeng;LI Shuaishuai;WANG Xuebin;SUN Xiaowei;TAN Houzhang(Shaanxi Yanchang Coal Yulin Energy and Chemical Co.,Ltd.,Yulin718501,China;School of Energy and Power Engineering,Xi'an Jiaotong Unviersity,Xi'an710049,China)
出处
《洁净煤技术》
CAS
2019年第2期83-88,共6页
Clean Coal Technology
基金
国家重点研发计划资助项目(2017YFB0603902)
关键词
气化细渣
燃烧
热重
混燃
协同效应
fine slag from gasification
combustion
TGA
co-combustion
synergistic effect
