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    基于粒度分级的煤气化细渣特性分析及利用研究

    Characteristic analysis and utilization of coal gasification fine slag based on particle size classification

    • 摘要: 煤气化过程中产生大量含碳量较高的气化细渣,目前主要以填埋方式处理,不仅占用大量土地,污染土壤和水体,同时造成能源浪费,对气化细渣进行高效环保的资源化利用是目前的研究热点。气化细渣中的残碳与灰组分分离是实现其高值化、减量化、无害化利用的关键,煤气化细渣粒度特性分析表明,各粒级产品灰分基本随粒级减小呈增大趋势,通过分级工艺可实现碳灰的分离与富集。榆林煤气化细渣固定碳含量随粒级减小均呈下降趋势,各粒级产品中均含有较多的SiO2、Al2O3、Fe2O3、CaO,微观形貌主要由多孔基体、不规则颗粒、黏附小颗粒及圆球颗粒组成。煤气化细渣孔隙结构发达,比表面积丰富,>75μm粒级产品可直接作为优质的吸附材料;与气化燃料煤相比,气化细渣各粒级产品燃烧的特征温度均显著提高,从着火温度看,除<45 um颗粒外,着火特征温度都高于作为参照的无烟煤;由于气化细渣中丰富孔隙率的存在,增大了颗粒与氧气的接触面积,使燃烧中后阶段燃烧峰值温度低于无烟煤,且燃尽温度明显低于无烟煤。

       

      Abstract: A large amount of gasification fine slag with high carbon content is produced in the process of coal gasification. At present,it is mainly treated by landfill,which not only occupies a lot of land,pollutes soil and water,but also causes energy waste. How to efficiently and environmentally utilize gasification fine slag as a resource is the hot spot of current research. The separation of residual carbon and ash in gasification fine slag is the key to realize its high value,reduction and harmless utilization. The analysis of particle size characteristics of gasification fine slag shows that the ash content of each particle size increases with the decrease of particle size,and the separation and enrichment of carbon and ash can be realized by screening and classification process. The results show that the fixed carbon content of Yulin coal gasification fine slag decreases with the decrease of particle size. There are more SiO_2,Al_2O_3,Fe_2O_3 and Ca O in each particle size.The micro morphology is mainly composed of porous matrix,irregular small particles,flocculent particles and spherical particles. The results show that the pore structure of coal gasification fine slag is developed,the specific surface area is rich,and the products with particle size >75 μm can be directly used as high-quality adsorption materials. Compared with the gasification fuel coal,the combustion characteristic temperature of each particle size of coal gasification fine slag is significantly increased,and the ignition characteristic temperature is higher than that of anthracite except for <45 μm particles. Due to the existence of rich porosity in gasification slag,the contact area between particles and oxygen is increased,so that the peak combustion temperature of combustion is lower than that of anthracite and the burnout temperature is significantly lower than that of anthracite in middle and later stage of combustion.

       

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