摘要
煤气化是煤炭清洁高效利用的关键技术,煤气化过程中产生了大量的细渣,细渣中复杂的碳-灰交融状态以及高水分含量限制了其资源化利用,碳灰分离是煤气化细渣资源化利用的必要前提。本研究采用泡沫浮选法对宁东地区3种不同气化工艺产生的细渣(SNB1细渣,XTY细渣和JC细渣)进行碳灰分离,分析了气化细渣及其碳灰分离产物的基本物性和持水能力,并借助傅里叶变换红外光谱仪、扫描电子显微镜和物理吸附仪研究,对比了气化细渣及其碳灰分离产物物理化学结构差异,以期为气化细渣的低成本处置与资源化利用提供参考。结果表明:通过泡沫浮选可以将3种细渣中的碳-灰进行不同程度的分离,泡沫浮选过程可以有效地将“游离”的球形矿物质颗粒与残碳颗粒进行分离,残碳表面和孔内灰颗粒相对更难去除。其中SNB1细渣的碳-灰分离效果最好,SNB1残碳中灰分降低至38.65%,SNB1尾灰中的灰分高达99.16%。经过泡沫浮选后,残碳和尾灰的持水能力相较于对应原气化细渣均有不同程度的降低,其中3种尾灰持水能力的降幅尤为显著(79.34%~96.61%)。此外,气化细渣及其碳灰分离产物中存在大量的圆柱形孔,碳-灰分离过程使得部分阻塞残碳颗粒中孔的微细球形矿物质颗粒脱离,从而使得残碳中微孔和中孔的数目增加,比表面积增大,而尾灰中主要以球形矿物质颗粒相互熔融而形成的缝隙中孔为主。碳灰分离过程使得部分夹带在残碳孔道内部的亲水性较强的微细球形矿物质颗粒被泡沫浮选过程去除,二氧化硅亲水位点相对减少,这使得3种残碳的持水能力相对于原气化细渣都有所降低。3种尾灰由于具有较低的比表面积(29.383~46.875 m^(2)/g),因而具有更低的持水能力。
Coal gasification is a key technology for the clean and efficient utilization of coal.A large amount of fine slag is produced during the coal gasification process.The utilization of gasification fine slag is limited by its complex carbon-ash fusion structure and high moisture content.The carbon ash separation is a necessary process for the utilization of gasification fine slag.In this study,the froth flotation method was used for the carbon-ash separation of gasification fine slags from three different gasification processes(SNB1 fine slag,XTY fine slag,and JC fine slag),then the basic properties and moisture holding capacity of gasification fine slag and its carbon-ash separation products were analyzed.Moreover,the Fourier transform infrared spectrometer,scanning electron microscope and physical adsorption instrument were adopted to comparatively study the physical and chemical structure of different gasification fine slag and its carbon-ash separation products,which is expected to provide reference for the low-cost disposal and resource utilization of gasification fine slag.The results show that the carbon and ash could be separated to varying degrees by the forth flotation process.The froth flotation process can effectively separate the spherical mineral particles that exist alone from the residual carbon particles.However,the spherical mineral particles melted or attached to the surface of the residual carbon particles and in the pores were difficult to be separated.Among them,the SNB1 fine slag has the best carbon-ash separation effect.The ash content in the SNB1 residual carbon was reduced to 38.65%.At the same time,the ash content of tail ash could be achieved to 99.16%.After froth flotation,the moisture holding capacity of the residual carbon and tail ash are reduced to varying degrees compared with the corresponding raw gasification fine slag,among which the decreasing amplitude of the moisture holding capacity of three kinds of tail ash is significant(79.34%-96.61%).There are a large number of cylindrical pores in the gasification fine slag and its flotation separation products.The carbon-ash separation process makes the fine spherical mineral particles,which blocked the pores of the residual carbon particles partially detached,resulted in the increase of micropores and mesopores in the residual carbon,thereby the specific surface area of residual carbon also increased.The pores in tail ash were mainly composed of the gaps formed by the mutual melting of spherical mineral particles.The carbon-ash separation process partially removed the hydrophilic fine spherical mineral particles entrained in the residual carbon pores.Thus,the silica hydrophilic sites in residual carbon were relatively reduced,which made the moisture holding capacity of the residual carbon reduced,compared with the raw fine slag.Due to the lowest specific surface area(29.383-46.875 m^(2)/g),the tail ash had the lowest moisture holding capacity.
作者
张一昕
郭旸
王如梦
贾文科
郭凡辉
武建军
ZHANG Yixin;GUO Yang;WANG Rumeng;JIA Wenke;GUO Fanhui;WU Jianjun(National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology,Xuzhou 221116,China;School of Chemical Engineering,China University of Mining and Technology,Xuzhou 221116,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2021年第S02期1096-1104,共9页
Journal of China Coal Society
基金
国家自然科学基金面上资助项目(51974311)
国家重点研发计划资助项目(2019YFC1904302)
山东省自然科学基金重点资助项目(ZR2020KE044)
关键词
煤气化细渣
碳灰分离
持水能力
化学结构
微观形貌
孔隙结构
coal gasification fine slag
carbon-ash separation
moisture holding capacity
chemical structure
microscopic morphology
pore structure
