System and method for graded rotary type air preheaters for reducing ammonium bisulfate deposition

Abstract

The invention discloses a system and method for graded rotary type air preheaters for reducing ammonium bisulfate deposition. The system is based on the graded rotary type air preheaters and mainly comprises the first stage rotary type air preheater, a flue gas on-line monitoring system, a reaction chamber, a dust remover, the second stage rotary type air preheater, a circulating air fan and an air feeder. According to the system and method for the graded rotary type air preheaters for reducing the ammonium bisulfate deposition, by means of the manner that the rotary type air preheaters are arranged in a graded manner, under the premise that the original heat transfer efficiency of the rotary type air preheaters is guaranteed, the ammonium bisulfate deposition and corrosion inside the airpreheaters and the cold end corrosion problem caused by sulfuric acid are significantly reduced; a one-stage air preheater frequently used in a boiler system is changed into two stages in the flowingdirection of flue gas, and the reaction chamber and the dust remover are arranged between the two stages; and by means of real-time feedback adjustment performed on the circulating air fan by the fluegas on-line monitoring system, the temperature of the flue gas at an inlet of the reaction chamber is made to be always maintained in a required range, and the safe and efficient operation of the system is guaranteed.

Description

technical field [0001] The present invention relates to a system and method for a graded rotary air preheater for mitigating ammonium bisulfate deposition. Background technique [0002] As we all know, selective catalytic reduction (SCR) flue gas denitrification technology has been adopted by a large number of coal-fired power plants to achieve NO x low emissions. Air preheater, as the equipment in the low-temperature area at the tail of the boiler, will inevitably suffer from low-temperature corrosion. SCR catalyst promotes NO x At the same time of the reduction reaction, it is inevitable that part of the SO in the flue gas 2 converted to SO 3 , the resulting SO 3 It can interact with the ammonia escaped from the SCR denitrification system to generate ammonium sulfate (AS) and ammonium bisulfate (ABS). Among them, ABS is hygroscopic, viscous and corrosive, and its melting point is 147°C. When the temperature is lower than the dew point temperature, ABS will deposit on...

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Problems solved by technology

[0004] Aiming at the serious clogging and corrosion problems that occur in the current rotary air preheater, the present invention proposes a system and method for a graded rotary air preheater for reducing the deposition of ammonium bisulfate

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