提高现有余热发电系统热效率的新思路探索

提出了水泥厂低温余热发电系统余热深度回收利用的技术路线,以解决水泥厂低温余热发电系统普遍存在的余热锅炉排烟温度过高和蒸发量不足的问题。提出的两种余热深度利用方案,分别为窑头余热锅炉排烟余热回收至给水系统技术路线(方案一)和窑头窑尾余热锅炉能量优化配置技术路线(方案二)。方案一通过加热窑头余热锅炉给水温度,将窑头余热锅炉排烟温度从115℃降低至85℃,提高了系统余热利用效率。方案二通过优化能量在窑头和窑尾余热锅炉之间的分配,将窑尾余热锅炉排烟温度从219℃降低至201.3℃,提高了系统余热利用效率。方案一低温余热发电系统的年收益为101.24万元/年,静态投资为190万元,静态投资回报期为1.88年。方案二低温余热发电系统的年收益为210.88万元/年,静态投资为165万元,静态投资回报期为0.78年。这两种方案均在节能方面具有显著的经济效益,符合国家节能减排的要求,对水泥厂低温余热发电系统的余热深度利用具有一定的指导意义。

New exploration to improve thermal efficiency of existing waste heat power generation system

In order to solve the problem of over temperature flue gas and insufficient evaporation capacity in the heat recovery boiler,the technical routes of waste heat depth utilization were proposed for the low-temperature cogeneration in cement plant.There were two technical routes of waste heat depth utilization:One was the waste heat recovery from the exhaust flue gas of the AQC boiler to the water supply system(Plan A).The other was the optimal energy partition between the AQC boiler and the SP boiler(Plan B).In plan A,the temperature of exhaust flue gas of AQC boiler was reduced from 115℃to 85℃,and the system waste heat utilization efficiency was improved.In plan B,the temperature of the exhaust flue gas of the SP boiler was reduced from 219℃to 201.3℃,and the system waste heat utilization efficiency was also improved.Plan A has an annual income of 1.0124 million yuan per year,a static investment of 1.9 million yuan and a static investment return period of 1.88 years.While plan B has an annual income of 2.1088 million yuan per year,a static investment of 1.65million yuan and a return period of 0.78 years.The two plans have remarkable economic benefits in energy conservation andemission reduction,which is beneficial to the waste heat depth utilization for the low-temperature cogeneration in cement plant.