某循环流化床锅炉增设低温省煤器降低排烟温度的节能分析

ADDING LOW TEMPERATURE ECONOMIZER TO A CFB BOILER FOR ENERGY SAVING

对某循环流化床(CFB)锅炉增设低温省煤器降低排烟温度的节能效果进行了分析。计算结果表明,抽水温度和回水温度越高,低温省煤器的节能效果越好。从6号低压加热器出口抽水,并回水至除氧器的方案1发电效率最高,与未采用低温省煤器相比,发电效率可提高0.34%;从6号低压加热器出口和7号低压加热器出口处抽水,混合后经低温省煤器回水至除氧器入口的方案2较方案1的换热器面积减少约1 000m2,发电煤耗降低约2.2g/(kW.h)。经综合比较,采用方案2改造后锅炉排烟温度降低近30℃,发电煤耗降低了1.6g/(kW.h),节能效果显著。

Installing low temperature economizer is an effective and low-cost way to reduce the exhaust temperature.This paper investigated the energy saving effect of this method.Results show that,the higher temperature of the pumping and returning water,the better economic efficiency of the economizer.Scheme 1 which pumps water from outlet of NO.6 low pressure heater and returns it to the deaerator has the maximum generation efficiency,which is improved by 0.34 percent compared with the boiler without low temperature economizer.Scheme 2 pumps water from the outlet of NO.6 and NO.7 low pressure heater,and returning it to the deaerator through the low temperature economizer after mixing.Compared with Sheme1,it can save heating surface area of about 1 000 m2.And the coal consumption for generation reduced by about 2.2 g/(kWoh) compared to the boiler without low temperature economizer.Finally,the boiler revamped by Scheme 2 has a dramatic energy saving effect because the exhaust temperature is decreased by about 30 ℃,and the coal consumption for generation decreased by 1.6 g/(kW·h).