Side-to-side thermal deashing method for rotary air preheater

Abstract

The invention relates to a side-to-side thermal deashing method for a rotary air preheater. The method is realized in a way that: loads of a primary air fan, a blowing fan and a draught fan are totally poured to one side by utilizing the low load of a generator set at night; a primary air fan, a blowing fan and a draught fan on the other side are shut down to change the heat transfer situations of the high, medium and low temperature heat transfer elements on the fan shut-down side of the rotary air preheater; a small amount of controlled hot fume at the preheater inlet on the fan shut-down side is utilized to heat the heat transfer elements, and meanwhile, primary cold air and secondary cold air are prohibited to enter the rotary air preheater, so that the heat transfer elements on the fan shut-down side of the rotary air preheater are only heated without releasing heat while rotating; and when the temperature of the heat transfer elements is raised almost to the temperature of the hot air and far higher than the dew point of ammonium bisulfate, ash deposit becomes loosened and the falls off. The invention can be used for periodically and thoroughly removing ash deposit on the heat transfer elements in the medium and high temperature sections, so that the ash deposit can not become severe. The invention can enhance the operating efficiency of the station boiler and lower the station service power consumption rate, and has the advantages of high effectiveness, energy saving, low carbon and emission reduction.

Description

(1) Technical field: [0001] The invention relates to a side-split hot ash cleaning method for a rotary air preheater used in a power station boiler. Serious fouling of the heat transfer elements in the middle and low temperature sections of the rotary air preheater will make the exhaust gas temperature of the power station boiler abnormally increase, and the boiler efficiency will decrease; it will increase the power consumption of the fan and the power consumption rate of the plant. The rotary air preheater split-side hot ash cleaning method of the invention can periodically and completely remove the ash deposits of the heat transfer elements in the middle and low temperature sections, so that the ash deposits will not develop to a serious level, and the invention can improve the operation efficiency of the power station boiler, It is an effective energy-saving, low-carbon and emission-reduction technology to reduce the power consumption rate of the plant. (2) Background te...

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Problems solved by technology

The oxidation characteristics of the SCR catalyst can convert a small amount of SO in the flue gas 2 Oxidation to SO 3 , SO 3 It can react with escaped ammonia to form ammonium bisulfate. The dew point of ammonium bisulfate is as high as 176°C. It cannot be blown through with a soot blower. The conventional denitrification rotary air preheater of a utility boiler adopts an increase in the height of the heat transfer element in the low temperature section and cancels the heat transfer element in the middle temperature section; the heat transfer element uses a small closed flow channel to ensure that the blowing air flow passes The use of enamel surface heat transfer elements; the use of duplex (steam and high-pressure water) soot blowing system; technical means such as increasing the exhaust gas temperature under the design load of power plant boilers, the adoption of these technical means has greatly improved Reduced the cost of the denitrification rotary air preheater, and also reduced the design efficiency of the power plant boiler

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