Jet and insert combined air pre-heater capable of realizing same inlet/outlet temperature difference of gas in heat exchange pipes

Abstract

The invention discloses a jet and insert combined air pre-heater capable of realizing same inlet / outlet equal temperature difference of gas in heat exchange pipes. The combined air pre-heater comprises a bellows and a plurality of rows of heat exchange pipes, wherein the bellows is provided with a cold air inlet and a hot air outlet, one side of the bellows is provided with a flue gas inlet, and the other side of the bellows is provided with a flue gas outlet; the plurality of rows of heat exchange pipes are arranged in the bellows and divided into a jet area and an insert area, the jet area is arranged at one side close to the flue gas inlet, and the insert area is arranged at one side close to the flue gas outlet; and the cold air inlet sequentially passes through the jet area and the insert area and then is communicated with the hot air outlet. Through the jet and insert combined air pre-heater capable of realizing the same inlet / outlet equal temperature difference of gas in the heat exchange pipes, the pipe wall temperature difference among the heat exchange pipes can be reduced, and the air heated in the heat exchange pipes has the same inlet / outlet temperature difference andthe optimal comprehensive heat exchange effect.

Description

technical field [0001] The invention relates to an air preheater, in particular to a combined air preheater with the same temperature difference between the inlet and outlet of a heat exchange tube and an insert. Background technique [0002] Jet-flow air preheater is widely used in chemical industry, metallurgy, energy power, building materials and other industrial fields. It is mainly used in waste heat utilization projects and air preheating projects of hot blast stoves, heating furnaces, industrial furnaces, boilers and other equipment. It can fully recover waste heat, provide pure high-temperature air, and save a lot of energy. With the enhancement of social environmental protection awareness and the pressure of energy shortage, higher and higher requirements are put forward for the heat utilization rate and function of the jet air preheater. [0003] At present, there are many types of air preheaters on the market, such as radiant air preheater, shell and tube air pre...

AI Technical Summary

Problems solved by technology

However, these air preheaters have the following problems: 1. The heat transfer principle of the air preheater is single, and the heat transfer capacity of the flue gas at different temperatures cannot be fully utilized, and the overall heat transfer performance is poor; 2. Generally speaking, The temperature of flue gas from hot blast stoves, heating furnaces, industrial furnaces, etc. is relatively high, up to 800-900°C. This high-temperature flue gas enters the air preheater to exchange heat with the air, which will inevitably affect the air preheater. The material requirements are very high, and will affect the service life of the air preheater; 3. The air preheater will be radiated by high-temperature flue gas for a long time during operation, especially the front heat exchange tubes at the entrance of the flue gas. The radiation of the flue gas is more serious, and the temperature is higher than that of other heat exchange tubes, which causes the thermal expansion of each row of heat exchange tubes to be different. When a heat exchange tube is damaged, the entire air preheater will be scrapped; 4. The air preheater needs to choose heat exchange tubes of different material types from the flue gas inlet to the outlet. Because the materials used for the heat exchange tubes are different, their thermal expansion capabilities are also very different, and it is difficult to avoid their thermal expansion performance mismatch. problems, all of these problems cause the air preheater to be expensive and have a short life, which affects the overall performance of the air preheater

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