Downstream ash blockage prevention system and ash blockage prevention method adopting smoke circulation

Abstract

The invention discloses a downstream ash blockage prevention system and ash blockage prevention method adopting smoke circulation. The downstream ash blockage prevention system adopting smoke circulation comprises a base assembly and a blockage prevention assembly, wherein the base assembly comprises an air preheater body; the air preheater body comprises a smoke channel, a secondary air channel adjacent to the smoke channel, and a primary air channel adjacent to the secondary air channel; and the blockage prevention assembly comprises a smoke branch bin formed in the smoke channel, a smoke branch sub-bin formed in the side part of the smoke branch bin, and a smoke flow adjustment device configured for the smoke branch sub-bin. According to the downstream ash blockage prevention system andash blockage prevention method adopting smoke circulation, the smoke branch sub-bin is formed in an area with a low-temperature corrosion risk in the smoke channel, an original smoke bin is improvedto be 1+1 smoke bin, and the smoke branch sub-bin becomes an independent and isolated smoke channel; and meanwhile, the smoke flow adjustment device is configured for the smoke sub-bin, and a smoke temperature of an outlet of the smoke sub-bin, and an outlet speed are controlled through the smoke flow adjustment device, so that unbalanced control over the flow of smoke passing through the smoke bin is realized.

Description

technical field [0001] The invention relates to a downstream anti-clogging ash device, in particular to a flue gas circulation downstream anti-clogging ash air preheater, which belongs to the technical field of energy saving. Background technique [0002] At present, the additional flue gas denitrification facilities in coal-fired power plants are mainly based on selective catalytic reduction (SCR) technology. The technology is injected into the SCR reactor , so that most of the smoke Reverted to environmentally friendly and . But during this process, two side reactions occur: + → and + + → , adversely affect the operation of the air preheater downstream of the denitrification unit. [0003] in the smoke It will combine with water vapor to generate sulfuric acid vapor, and the higher the concentration, the higher the acid dew point of the flue gas, which can reach 140-160°C or even higher. The liquid droplets not only aggravate the low-temperatur...

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Problems solved by technology

But during this process, two side reactions occur: + → and + + → , adversely affect the operation of the air preheater downstream of the denitrification unit

[0003] in the smoke It will combine with water vapor to generate sulfuric acid vapor, and the higher the concentration, the higher the acid dew point of the flue gas, which can reach 140-160°C or even higher. The liquid droplets not only aggravate the low-temperature corrosion problem of the air preheater, but also absorb fly ash more easily; in addition, the generated It is liquid in the temperature range of 146-207°C, and has very strong viscosity, which is very easy to catch fly ash. If it is not cleaned in time, the fly ash adhering to the surface of the heat storage element will form hard lumps, resulting in conventional steam blowing. The ash is difficult to remove effectively, eventually forming ash plugging

[0004] Due to the dust blocking of the air preheater caused by the denitrification system put into operation, it has seriously threatened the safe operation of the unit. The phenomenon of corrosion and dust blocking of the air preheater of coal-fired boilers in my country is becoming more and more serious, and its performance has two notable characteristics. One is that more and more units have the problem of dust blocking in the air preheater, and the other is that the degree of dust blocking is becoming more and more serious. The designed air preheater flue gas side resistance is usually around 1000Pa, and the actual resistance is as high as 3000Pa. Some are even as high as 4000Pa, and thus forced to apply for shutdown or cause non-stop accidents of the unit, which seriously affects the safety and normal production of power generation

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