A low temperature liquid nitrogen heat exchanger with adjustable temperature difference

Abstract

The invention discloses a low-temperature liquid nitrogen heat exchanger with adjustable temperature difference, which comprises a shell, a heat exchange tube, a baffle plate, a fan and a temperature measuring device; Separated into a heat exchange area, a liquid nitrogen evaporation area and a reflux channel, it is convenient for the recycling of low-temperature nitrogen; the number of the heat exchange tubes is divided into multiple groups, and they are arranged in layers from top to bottom in the heat exchange area. The tubes are divided into multiple layers, and each layer of heat exchange tubes is arranged in a serpentine shape, which makes the structure more compact while ensuring the heat exchange area; the baffles are arranged in the heat exchange area of ​​the housing; the fans are arranged On one side of the housing, a guide cover is also provided to increase the flow rate of low-temperature nitrogen and enhance the turbulence effect; a liquid nitrogen shower is arranged in the liquid nitrogen evaporation area, and the liquid nitrogen inlet of the liquid nitrogen shower An electromagnetic control valve is installed on the pipeline, which can adjust the amount of liquid nitrogen spraying according to the temperature difference obtained by the temperature measuring device, so as to realize the control of the maximum temperature difference.

Description

technical field [0001] The invention relates to a heat exchanger, in particular to a low-temperature liquid nitrogen heat exchanger with adjustable temperature difference. Background technique [0002] Liquid nitrogen is an excellent refrigerant, its lowest refrigeration temperature can reach -180°C, and it has the advantages of no pollution, low price and easy availability, so it has been widely used in the field of industrial refrigeration. The Chinese patent application publication number CN109764698A discloses a liquid nitrogen refrigerant heat exchanger, including a shell, supporting baffles and finned tubes; the Chinese patent application publication number CN102338573A discloses a highly efficient and compact cryogenic liquid nitrogen A heat exchanger comprising multiple layers of cross-helically wound elastic tube bundles. These structures overcome the problems of small heat exchange area and large thermal stress of traditional shell-and-tube heat exchangers. Howeve...

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Problems solved by technology

These structures overcome the problems of small heat exchange area and large thermal stress of traditional shell-and-tube heat exchangers. However, liquid nitrogen is used as the refrigerant for direct heat exchange, and the heat transfer temperature difference is large and cannot be adjusted. There are strict requirements on the temperature difference; at the same time, the vaporized nitrogen is directly discharged, and the cold energy is not fully utilized, which increases the consumption of liquid nitrogen

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