摘要
排烟热损失为锅炉热损失的最主要部分,采用低低温省煤器进行尾部烟气余热回收可以提高机组效率,但自超低排放改造完成后,脱硝氨气过喷导致低低温省煤器普遍出现硫酸氢铵腐蚀和堵塞问题,流场不均引起的局部磨损问题也日益凸显。以某电厂2台600MW机组低低温省煤器改造为例,首先对低低温省煤器运行中存在的问题进行摸底试验,然后提出低低温省煤器功能性恢复及提升改造的具体方案,主要改造内容是对换热管进行更换,将材质比例由60%20G+40%ND钢升级为50%20G+50%ND钢并将H型翅片间隙由10mm调整为15mm,最后对改造后的引风机能耗降低量进行估算,并利用等效焓降法对改造前后的发电煤耗节约量进行计算和对比。相比改造前,3、4号机组引风机能耗分别降低706kW和353kW,折算到年生产成本分别节约162万元和81万元,余热回收系统节约发电标煤耗分别为0.47g/(kW·h)和0.24g/(kW·h),折算到年收益增量分别为85万元和43万元,投资回收期约为3.78年,节能收益显著,机组运行经济性有较大改善。通过改造实例的详细论述,以期为其他电厂低低温省煤器的功能性恢复改造工作提供有效指导。
Exhaust heat loss is the main part of the boiler heat loss,adopting ultra-low temperature economizer for tail flue gas waste heat recovery can improve the efficiency of the unit.But since the ultra-low emission renovation completes,excessive spraying denitration ammonia leads to ultra-low temperature economizer with general problems of ammonium bisulfate corrosion and blockage,partial wear problems are caused by the uneven flow field are also growing.This paper takes the renovation of ultra-low temperature economizers of two 600MW units in a power plant as an example.Firstly it analyzes the problems existing in the operation of ultra-low temperature economizers,and then proposes the specific scheme of functional recovery and upgrading of ultra-low temperature economizers.The main renovation content is to replace the heat exchange tubes,upgrade the material proportion from 60%20G+40%ND steel to 50%20G+50%ND steel,and adjust the H-fin gap from 10mm to 15mm.Finally,the energy consumption reduction of the induced draft fans after renovation is estimated,and uses equivalent enthalpy drop method to calculate and compare the coal consumption saving of power generation before and after the renovation.Compared with the former,the energy consumption of the induced draft fans of unit 3 and unit 4 are reduced by 946kW and 473kW respectively,and the annual production costs are saved by 2.17 million yuan and 1.08 million yuan respectively after conversion.The standard coal quantity of power generation are saved by the waste heat recovery system is 0.47g/(kW·h)and 0.24g/(kW·h)respectively,and the annual benefit increment are 850 thousand yuan and 430 thousand yuan respectively.The investment payback period is about 3.78 years.The energy saving benefit is significant and the unit operation economy is greatly improved.Through detailed discussion of the renovation example in this paper,it is expected to provide effective guidance for functional recovery renovation of ultra-low temperature economizers in other power plants.
作者
张志中
刘强
刘沛奇
胡妲
唐郭安
杜振
ZHANG Zhizhong;LIU Qiang;LIU Peiqi;HU Da;TANG Guoan;DU Zhen(Huadian Electric Power Research Institute Co.,LTD.,Hangzhou 310030,China)
出处
《电力科技与环保》
2022年第3期202-208,共7页
Electric Power Technology and Environmental Protection
基金
中国华电集团有限公司科技项目(CHDKJ20-02-75)。
关键词
低低温省煤器
硫酸氢铵
腐蚀和堵塞
发电标煤耗
节能收益
ultra-low temperature economizer
ammonium bisulfate
corrosion and blockage
standard coal consumption of power generation
energy saving benefit
