脱硫废水蒸发系统对燃煤电厂水平衡及氯平衡的影响

Effect of Desulfurization Wastewater Evaporation System on Water and Chlorine Balance of Power Plant

以某电厂脱硫废水旁路蒸发系统作为研究对象,全面分析了该系统对全厂水平衡及氯平衡的影响。结果表明:废水蒸发造成脱硫塔入口烟气温度降低2~5 K,且可在一定程度上降低工艺水的用量;旁路蒸发系统投运后,约有3%氯离子再释放为气态HCl,造成干燥塔出口氯质量浓度提升至75.6 mg/m^(3);剩余的氯引入飞灰中,造成主烟道飞灰中氯质量分数上升至1 mg/g;虽然飞灰中氯含量有所增加,但对电厂粉煤灰综合利用的影响十分有限。

Using the desulfurization wastewater bypass evaporation system of a power plant as the study object,the effect of the system on water and chlorine balance of the whole plant was comprehensively analyzed.Results show that wastewater evaporation causes a temperature drop of 2-5 K in the flue gas at inlet of desulfurization tower,and reduces the usage of process water to a certain degree.After the commissioning of the bypass evaporation system,about 3%of the chloride ions are released as gaseous HCl,causing the increase of mass concentration of chlorine to 75.6 mg/m^(3)at outlet of the dry tower.The residual chlorine is introduced into the fly ash,resulting in the increase of mass fraction of chlorine in fly ash of main flue to 1 mg/g.Although the chlorine content in fly ash is increased,the effect on the comprehensive utilization of fly ash in power plant is very limited.