Low temperature protection device for metal heat exchange tube of preheater

Abstract

The invention discloses a low-temperature protective device of a preheater metal heat-exchange tube. A plurality of metal heat-exchange tubes are arranged in parallel among an air input collection header, an air output collection header and an air bottom connection header at intervals, and are used for communicating the air input collection header with the air bottom connection header and communicating the air bottom connection header with the air output collection header respectively; the air input collection header and the air output collection header are respectively provided with an air input interface and an air output interface; a hot air collection header is sleeved on the top of the air input collection header; the bottom of one side of the hot air collection header is provided with a hot air spout towards the plurality of metal heat-exchange tubes; the hot air interface is arranged at the top of the hot air collection header; and the air input interface of the air input collection header passes through the hot air collection header and is connected with the air input collection header. By adopting the device, acid corrosion of a low-temperature tube bank of a preheater is avoided effectively, the heat recycling efficiency of the preheater is increased, the service life of the preheater is prolonged, and the energy consumption is lowered.

Description

technical field [0001] The invention relates to a low temperature protection device for a metal heat exchange tube of a preheater. Background technique [0002] The preheater utilizes the recovered flue gas waste heat to increase the temperature of the combustion-supporting gas entering various furnaces or boilers. Exhaust smoke temperature, increase combustion gas temperature, reduce energy consumption. Such as figure 1 As shown, the structure of the general preheater includes an air bottom connection box 1, an air input header 2, an air output header 3 and several metal heat exchange tubes 4, and the air input header 2 and the air output header 3 are arranged side by side and respectively An air input interface 21 and an air output interface 31 are provided. The air bottom connection box is located at the lower part of the air input header 2 and the air output header 3. Several metal heat exchange tubes 4 are arranged in parallel and spaced between the air input header 2...

AI Technical Summary

Problems solved by technology

Generally, in order to avoid low-temperature corrosion caused by the temperature of the low-temperature tube group 42 of the preheater being lower than the acid dew point temperature, in addition to using more corrosion-resistant materials in the low-temperature section, most of them adopt control of the flue gas outlet temperature of the preheater to be much higher than the acid dew point temperature. Or use an external heat source or hot air circulation to increase the air temperature before entering the preheater, which prevents a large amount of waste heat from the flue gas from being effectively recycled and reduces the heat transfer efficiency of the preheater

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