煤焦还原分解烧结烟气脱硫石膏的试验

Experimen on coal char reductive decomposition and sintering flue gas desulfurization gypsum

针对烟气脱硫石膏综合利用问题,提出了利用煤焦还原分解石膏制备CaO和SO2的新方法。采用FactSage 6.1计算了煤焦与脱硫石膏的高温反应特性,并利用热重分析仪在理论上分析了煤焦还原分解石膏行为的可行性。通过管式电阻炉试验进一步研究了温度、煤焦添加量、保温时间对石膏分解率和固态产物影响以及气体SO2释放规律。试验结果表明,升高温度、增加煤焦添加量和保温时间均能提高石膏的分解率;煤焦质量分数从5%增加到20%,CaO和SO2的质量分数先升高后下降,而CaS的质量分数一直增大;在煤焦量为11%时,CaO和SO2的质量分数达到最大值,CaO和SO2成分的变化规律主要受CaS和CaSO4相对含量的影响。采用煤焦还原分解石膏的方法,可为石膏综合利用提供理论指导。

Aiming at the problem of comprehensive utilization of the flue gas desulfurization gypsum,a new method for preparing CaO and SO2 by using the coal char to reduce and decompose gypsum was proposed.The high-temperature reaction characteristics of coal char and desulfurization gypsum were calculated by FactSage 6.1,and the behavior of coal char reduction and decomposition gypsum was theoretically analyzed by a thermogravimetric analyzer.Effects of temperature,coal coke addition and holding time on the gypsum decomposition rate,solid product and gas SO2 release were further studied by tubular resistance furnace experiments.The results show that increasing the temperature,increasing the amount of coal char and increasing the holding time can increase the decomposition rate of gypsum.When the amount of coal coke increases from 5%to 20%,the mass percent of CaO and SO2 increases first and then decreases,while the mass percent of CaS always increases.When the coal coke amount is 11%,the content of CaO and SO2 reaches the maximum value.The variation of CaO and SO2 components is mainly affected by the relative contents of CaS and CaSO4.The use of coal char to reduce and decompose gypsum can provide a theoretical guidance for the comprehensive utilization of gypsum.