Hot gas comprehensive purification device for preventing dew point corrosion at boiler tail

Abstract

The invention discloses a hot gas comprehensive purification device for preventing the dew point corrosion at a boiler tail, which comprises a purification device body and an inclined partition plate.The tail heating surface is divided by the inclined partition plate into an upper chamber and a lower chamber which are independent from each other. The purification device body is internally and sequentially provided with an SCR denitration layer, a soda lime desulfurization layer, a secondary air preheater and a super absorbent resin layer from top to bottom. The purification device body is communicated with the upper chamber through an air inlet pipeline and is communicated with the lower chamber through an air outlet pipeline. A dust collecting groove, a dust removing net and a primary air preheater are arranged in the air inlet pipeline, and ultrasonic dust removers are arranged on the outer walls of the air inlet pipeline and the purification device body.According to the hot gas comprehensive purification device, the dust removal net and the three purification layers are used for reducing the contents of large-particle dust, nitrogen oxide compounds, sulfur oxide compounds and water vapor in the hot gas at the boiler tail, so that the occurrence of the dew point corrosion of a low-temperature heating surface at the boilertail is avoided, and the abrasion of dust particles onthe outer wall of an air preheater pipeline and dust deposition are slowed down.

Description

Technical field [0001] The invention relates to the field of environmental treatment, in particular to a comprehensive hot gas purification device for preventing dew point corrosion at the tail of a boiler. Background technique [0002] Dew point corrosion on the heated surface of the boiler tail: Because coal itself contains certain sulfur elements, the flue gas after combustion contains sulfur trioxide. When the tube wall temperature is lower than the flue gas dew point, the water vapor containing sulfate in the flue gas is on the tube wall Upper condensation, which mostly occurs in the low temperature section of the air preheater. When the sulfur content in the fuel is high and the excess air coefficient is large, SO in the flue gas 3 When the content is higher, the acid dew point rises, and the feed water temperature is lower, the economizer tube may also undergo low-temperature corrosion, causing the heated surface to corrode and perforate and leak air. Due to the wet and ro...

AI Technical Summary

Problems solved by technology

SCR denitrification technology converts nitrogen oxides into nitrogen and water vapor, but other components in the hot gas in the boiler will also react with the catalytic layer to produce harmful substances such as ammonium bisulfate and sulfur trioxide, and sulfur trioxide is the main cause of dew point corrosion The culprit is that ammonium bisulfate is a highly viscous and highly acidic substance, which is liquid at high temperature and can easily cause pipe wall corrosion and blockage

At the same time, the SCR catalyst also has problems such as ammonia leakage.

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