燃煤电厂灰水pH值变化规律及其CO2调整理论分析

讨论了燃煤电厂水力除灰系统灰浆pH值变化规律.灰浆初始pH值受除尘器类型影响,干式除尘器远大于湿式除尘器；灰浆在输往灰场过程中,灰中游离氧化钙的溶出会使灰浆pH值不断上升；在灰场入口,灰浆pH值达到最高;水与灰在灰场中分离,并吸收空气中CO2,使水pH值下降,最后排出灰场.针对灰浆pH值变化规律和除灰系统的结构特点,从理论上论证了CO2投入点的选择依据及投加量的估算方法.

The pH change of ash transport water in coal-fired power plant and theoretical analysis of CO2 for its adjustment

The pH change of ash transport water in coal-fired power plant is discussed and CO2 for its adjustment is analyzed theoretically. The initial pH of ash transport water is affected by the type of dust collector, the pH of the water for dry type of dust collector being higher than that for wet type. The pH of the water is increasing during its transport through the pipe because of the dissolution of free CaO in the fly ash; and the highest pH of the water is approached at the inlet of ash pond. At outlet of the ash pond, lower pH water is discharged after the seperation of ash from water because of the adsorption of CO2 from atmosphere. Based on the trend of pH change of ash transport water and characteristic of ash hydraulic transport system, the rule for the selecting of CO2 injection points and the methods for the estimating quantity of CO2 addition are analyzed theoretically.