电厂粉煤灰固定二氧化碳实验研究

Experimental Study on Solidification of Carbon Dioxide by Coal Fly Ash in Power Plant

通过湿法碳酸化的方法研究不同固液比(质量比)、温度、压力和反应时间对粉煤灰固定CO_2的影响。采用XRF,XRD和SEM-EDS分析了粉煤灰和固化产物的相组成和微观结构。结果表明:粉煤灰固定CO_2的量随着温度升高和固液比增加而降低;当反应温度、反应时间、初始压力、固液比和搅拌速度分别为60℃,120min,3.6 MPa,1∶2.5和300r/min时,粉煤灰固碳效率可达69.98%。1t粉煤灰可固定43.13kg CO_2。不同温度下粉煤灰固定CO_2的准一级动力学方程拟合曲线的R^2均值为0.875;准二级动力学方程拟合相关性更好,R^2均值为0.947;随着温度降低,准二级动力学方程的速率常数增大。

The effects of different solid-liquid ratios(mass ratio,the same below),temperatures,pressures and reaction times,on the effect of CO2 sequestration by coal fly ash were studied by the means of aqueous carbonation.XRF,XRD,and SEM-EDS methods were used to analyze the phase composition,and microstructure of the coal fly ash slag material and cured product.The results show that as the increase of temperature and the enlargement of solid-liquid ratio,the amount of CO2 fixed by coal fly ash decreases.When the reaction temperature,reaction time,initial pressure,solid-liquid ratio and stirring speed are 60℃,120 min,3.6 MPa,1∶2.5 and 300 r/min respectively,the carbonation efficiency of coal fly ash reaches 69.98%.1 t of coal fly ash can sequester up to 43.13 kg CO2.At different temperatures,the average R 2 values of the quasi-first-order kinetic equations fitting curves of the coal fly ash fixed CO2 is 0.862,and the average R 2 values for the quasi-second-order kinetic curve is 0.910.The results show that the fitting correlation of the quasi-second-order kinetic is better.And with the reduction of temperature,the rate constant of the quasi-second-order kinetic equation increases.