水力旋流筛分组合用于气化细灰的碳灰分级试验研究

Study on classification carbon and ash of gasification fine ash by combination of hydrocyclone and vibrating screen

气化细灰具有较高的残碳和丰富的无机矿物组成,两者资源属性不同制约着气化细灰的大规模利用,通过对气化细灰进行碳-灰分级研究,有利于气化细灰源头减量及分质资源化利用。以GE水煤浆气化工艺产生的细灰为研究对象,研究其碳灰分布特征及水力旋流筛分组合对细灰的分级效果,并通过BET、TG测定了高碳细灰的孔隙及吸附特征和反应活性,探索气化细灰资源化利用的途径。结果表明:气化细灰的灰成分主要含有SiO_(2)、Al_(2)O_(3)、Fe_(2)O_(3)和CaO,与硅酸盐水泥成分相近;气化细灰中的灰分主要以球状颗粒独立存在或黏附于残碳表面和孔隙中,可通过物理方法对碳-灰进行分级;物料浓度、入料压力和底流口径等是影响水力旋流器分选气化细灰效果的主要参数,随着入料浓度的增大,水力旋流器分选气化细灰的效率先增加后降低,旋流器底流产品的灰分随入料压力的增加先降低后增加,采用水力旋流+筛分组合工艺处理气化细灰,可进一步得到灰分较低的高碳细灰产品;高碳细灰的孔隙发达,比表面积较大约352 cm^(3)/g,反应活性良好,在小于1200℃条件下,高碳细灰中的可燃物可完全与二氧化碳反应。高碳细灰的吸附特性和与二氧化碳的反应特性的结果表明,其可作为低品质吸附材料或返回气化炉气化进行资源化利用。

Coal gasification fine slag has high residual carbon and rich inorganic mineral composition,the different resource properties of the two components restrict the large-scale utilization of gasification fine slag,the research on carbon ash classification is conducive to the source reduction and quality resource utilization of gasification fine slag.Fine slag produced by GE coal water slurry gasification process was selected for investigation,the carbon ash distribution and classification technology were studied.Based on the distribution of carbon and ash in fine slag,the classification effect of hydrocyclone screening combination on fine slag was studied.The pore and adsorption characteristics and reaction activity of the gasification fine slag were systematically studied by BET surface area measurement and thermogravimetric analyzer,expected to develop a new process for resource utilization of gasification fine slag.The results show that the ash composition of fine slag is mainly SiO_(2),Al_(2)O_(3),Fe_(2)O_(3) and CaO,which is similar to that of port land cement.Most of the ash in fine slag exists independently as spherical particles or adheres to the surface and pores of residual carbon.Carbon and ash can be preliminarily classified by physical methods.Concentration of fine mortar,input pressure and underflow diameter are the main parameters of hydrocyclone for separating fine slag,when the concentration of materials increases,the separation efficiency of hydrocyclones increases firstly and then decreases,the ash content of the underflow product decreases and then increases with the increase of the feed pressure.Using the combined process of hydrocyclone and screening to treat the fine slag,the product with high carbon can be obtained.The pores of high carbon fine slag are developed,and the specific surface area is about 352 cm~3/g.Under the condition of less than 1200℃,the combustibles in high carbon fine slag can completely react with carbon dioxide.The adsorption characteristics of high carbon fine slag and its reaction with carbon dioxide show that it can be used as low-quality adsorption material or returned to gasifier to increase its economic benefits.