燃煤电厂深度调峰下湿法脱硫石膏脱水困难分析与治理

Analysis and Treatment of Wet Desulfurization Gypsum Dehydration Difficulties Under Deep Peak Shaving in Coal Fired Power Plants

某燃煤电厂2×350 MW机组脱硫石膏含水率高,影响脱硫石膏循环利用,造成脱硫系统二次污染。通过分析脱硫脱水系统设备状况、运行参数和石膏结晶情况,确定导致脱水困难的原因,在频繁深度调峰负荷下,脱硫系统不能快速适应机组负荷变化,脱硫浆液过饱和度较高,使石膏生成速率远大于其生长速率,生成大量小晶体难以脱水。采取添加石膏晶体、增加浆液固体停留时间及降低运行pH值等多种措施使石膏脱水恢复正常,为存在类似问题的燃煤电厂提供参考。

A coal fired power plant has 2×350 MW units with high moisture content in desulfurization gypsum,which affects the recycling of desulfurization gypsum and causes secondary pollution in the desulfurization system.By analyzing the equipment condition,operating parameters,and gypsum crystallization of the desulfurization and dehydration system,it is determined that the reason for the difficulty in dehydration is that the desulfurization system cannot quickly adapt to changes in unit load under the recent frequent deep peak load shaving regulation.The high supersaturation of the desulfurization slurry results in a much faster gypsum generation rate than the growth rate of gypsum,which generates a large number of small crystals that are difficult to dehydrate.Various measures such as adding gypsum crystal seeds,increasing the solid retention time of the slurry,and reducing the operating pH value are taken to restore normal gypsum dehydration.It provides reference for coal fired power plants with similar problems.