Adding low pressure economizer is an effective way to reduce the exhaust flue gas temperature of boiler in a power plant

but it would result in low temperature corrosion.Increasing wall temperature of the low pressure economizer can inhibit the low temperature corrosion effectively.A scheme of laying coating with low thermal conductivity on the inner wall of the low pressure economizer in low temperature duct was put forward.Taking a 1 000 MW unit as the example

the influence of coating thickness on the wall temperature and heat transfer coefficient of the heating surface was analyzed.The results show that

laying low heat transfer coefficient coating with thickness of 0.2 mm on low temperature inner surface can decrease the total heat transfer coefficient of the low pressure economizer by 9.1%

increase the heat transfer temperature difference by 33.3%

thus to save the heating surface by about 13.0%and reduce the flue gas resistance by 70 Pa.