Jet-flow air pre-heater with heat exchange tubes having same inlet and outlet temperature difference

Abstract

The invention discloses a jet-flow air pre-heater with heat exchange tubes having the same inlet and outlet temperature difference. The air pre-heater comprises a wind box and a plurality of rows of heat exchange tubes, wherein a cold air inlet is arranged at the upper end of the wind box; a hot air outlet is arranged at the lower end of the wind box; a fume inlet is arranged on one side of the wind box; a fume outlet is arranged on the other side of the wind box; the plurality of rows of heat exchange tubes are uniformly arranged in the wind box and communicated with the cold air inlet and the hot air outlet; the heat exchange tubes consist of internal tubes and external tubes which are sleeved coaxially; and the internal tubes are jet-flow tubes in which a plurality of jet-flow holes are formed. The jet-flow air pre-heater with the heat exchange tubes having the same inlet and outlet temperature difference has the advantages that: the temperature difference between tube walls of the heat exchange tubes can be reduced; and air which is heated in each row of heat exchange tubes has the same inlet and outlet temperature difference and the jet-flow air pre-heater has an optimal comprehensive heat exchange effect.

Description

technical field [0001] The invention relates to an air preheater, in particular to a spray air preheater with the same temperature difference between the inlet and outlet of a heat exchange tube. 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] The jet-flow air preheater is mainly used to recover the waste heat of high-temperature flue gas, and its temperature is as high as 800-...

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Problems solved by technology

[0003] The jet-flow air preheater is mainly used to recover the waste heat of high-temperature flue gas, and its temperature is as high as 800-900°C, so it will be subjected to the heat radiation of high-temperature flue gas for a long time during operation, especially near the flue gas inlet. The flue gas heat radiation of the first few rows of heat exchange tubes is more serious, and the temperature it bears is much higher than that of the heat exchange tubes in the middle position, which causes the thermal expansion of each row of heat exchange tubes to be different. When the tube is damaged, the entire jet-flow air preheater will be scrapped. Therefore, in the design and manufacturing process, heat exchange tubes of different materials and types are usually selected from the flue gas inlet to the outlet. The high temperature resistant alloy pipe is selected for the pipe, and the general stainless steel pipe is used for the heat exchange pipe at the outlet of the flue gas. However, due to the different materials selected for the heat exchange pipe, their thermal expansion capabilities are also very different. , it is easy to cause damage to individual heat exchange tubes due to thermal expansion mismatch, which makes the jet air preheater expensive and short in life, affecting the overall performance of the jet air preheater

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