Combined air preheater

Abstract

The invention discloses a combined air preheater. A hot flue gas inlet flue communicates with a cold flue gas outlet flue through a flue gas side rotary air preheater, a medium-temperature flue gas outlet flue, a medium-temperature flue gas inlet flue and a heat release side of a tubular air preheater system. A cold air inlet air flue communicates with a hot air outlet air flue through a heat absorption side of the tubular air preheater system, a medium-temperature air outlet air flue, a medium-temperature air inlet air flue and an air side rotary air preheater. The combined preheater can effectively increase the temperature of outlet exhausted smoke of the rotary air preheater, solves the problem that ammonium bisulfate ash clogging influences the rotary air preheater, and is high in safety and stability.

Description

technical field [0001] The invention belongs to the technical field of generator sets, and relates to a combined air preheater. Background technique [0002] Air preheater is widely used in thermal power generating units. It can reduce the exhaust gas temperature of the unit, increase the temperature of the air required for combustion, and greatly improve the thermal efficiency of the boiler. Air preheaters are mainly divided into rotary air preheaters and tubular air preheaters. Rotary air preheaters have high heat exchange efficiency and small size, and are mainly used in large-capacity units of 300MW and above, while tubular air preheaters The preheater is simple to manufacture and has a small air leakage rate, and is mainly used in small units of 200MW and below. [0003] After the implementation of the ultra-low emission policy, the NOx concentration is required to be no more than 50mg / m 3 , the generating units have all undergone denitrification transformation. The d...

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Problems solved by technology

The main problems faced by rotary air preheaters are increased resistance and decreased heat transfer efficiency due to ammonia slip

[0004] In order to solve the clogging problem of ammonium bisulfate, the air preheater is equipped with a high-pressure water gun online flushing device at the cold end, but the thickness of the ammonium bisulfate clogging ash is more than 1m, and it is difficult to completely solve the clogging problem

In addition, the low-temperature section of the air preheater is replaced with a large-channel heat exchange plate, which is conducive to online cleaning, but the large-channel heat exchange plate will reduce the heat exchange efficiency of the air preheater, which will increase the exhaust gas temperature at the outlet of the air preheater and reduce the temperature. boiler efficiency

[0005] The tubular air preheater also has the problem of ammonium bisulfate clogging

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