70 MW链条燃煤锅炉改天然气锅炉技术经济性分析

Technical and economical analysis for modification of a 70 MW chain coal-fired boiler to natural gas boiler

根据国家治污减霾政策要求,燃煤供热锅炉上大压小,淘汰小型燃煤供热锅炉,采用集中供热或新建大型燃气锅炉等,这样北方城市供热的大批小型链条燃煤锅炉将面临关停淘汰或需要进行煤改气。本文针对某热力公司70 MW链条燃煤锅炉改天然气锅炉进行了技术研究,介绍了改造技术方案及其效果,并对改造前后环保参数、经济性等进行了对比分析。结果表明:“煤改气”从技术上可以实现锅炉稳定运行,热效率达到95%以上;从环保上可以实现超低排放,NOx排放质量浓度低于30 mg/m^3;从经济性上虽然增加了燃料费用,但减少了脱硫、脱硝、除尘等环保费用、厂用电量、燃料运输及人工成本等费用。

To satisfy the requirements of national pollution control and haze reduction policies,large scale coalfired heating boilers can be put into service but the small scale ones should be shut down,and centralized heating or new large-scale gas boilers should be used.As a result,a large number of small scale chain coal-fired boilers for heating in northern cities are facing shutdown,phased out or coal-to-gas conversion.In this paper,the technical study is carried out on the basis of a 70 MW chain coal-fired boiler which is modified into a natural gas boiler.The technical scheme and modification effect are introduced in detail,and the environmental protection parameters and economics before and after the modification are compared.The results show that,from the technical level,“coal to gas”can realize stable operation of the boiler,and the boiler thermal efficiency can reach higher than 95%.From the environmental protection level,ultra-low emission can be achieved,the mass concentration of NOx emission is able to be controlled below 30 mg/m^3.From the economic level,although the fuel cost increases,the costs of desulfurization,denitrification,dust removal and other environmentally-friendly consumables and equipment costs,factory power consumption,fuel transportation and labor costs are reduced.