Single-flow low-temperature spiral winding tube type heat exchanger with vacuum heat-insulation effect

Abstract

A single-flow low-temperature spiral winding tube type heat exchanger with a vacuum heat-insulation effect mainly comprises a spiral winding tube bundle and a vacuum shell. A winding equation of a novel spiral tube bundle theory is applied, a mathematical model is built and applied to a numerical simulation process of a flow field, accordingly, a computation method of the tube bundle winding theory is obtained, and the spiral winding tube type heat exchanger is designed and manufactured. The vacuum heat-insulation technology is applied to the single-flow low-temperature spiral winding tube type heat exchanger, a vacuum structure consisting of an upper gland, a lower gland and a barrel which are independent from each other is adopted, and shortcomings that a traditional vacuum structure and a tube nest bundle are combined difficultly and inconvenient in manufacture, installation, detachment and maintenance and the like are overcome. The single-flow low-temperature spiral winding tube type heat exchanger is applicable to technical fields of gas purification and liquefaction separation including natural gas low-temperature liquefaction at the temperature of minus 161 DEG C, air low-temperature liquefaction separation at the temperature of minus 197 DEG C, low-temperature liquid-nitrogen washing at the temperature of minus 197 DEG C, low-temperature methanol washing at the temperature of minus 70 DEG C and the like, low-temperature heat exchange efficiency can be improved, and the single-flow low-temperature spiral winding tube type heat exchanger has the advantages that the single-flow low-temperature spiral winding tube type heat exchanger is compact in structure, heat transfer area of unit volume is large, heat expansion can be automatically compensated, the heat exchanger can be enlarged easily, the quantity of heat exchange equipment can be reduced, and the like.

Description

technical field [0001] The invention relates to a single-flow low-temperature spiral wound tube heat exchanger with vacuum insulation, which is mainly used in the field of low-temperature liquefaction and separation of gases, including low-temperature liquefaction of natural gas at -161°C, low-temperature liquefaction and separation of air at -197°C, and low-temperature liquefaction at -197°C Liquid nitrogen washing process, -70 ℃ low temperature methanol washing process and other gas low temperature purification, low temperature liquefaction separation technology fields. Background technique [0002] Spiral wound tube heat exchanger is a kind of heat exchange equipment, which is mainly used in low temperature heat and mass exchange process. It has a compact structure and a large heat transfer area per unit volume. The thermal expansion of the heat transfer tube can be compensated by itself, and it is easy to realize large-scale With the advantages of reducing the number of ...

AI Technical Summary

Problems solved by technology

Since spiral wound tube heat exchangers are mostly used in low temperature environments, they are large in size and generally appear in the form of heat transfer towers, up to seventy or eighty meters high. Multi-stream heat exchange is the main method, the internal pipes are complicated to wind, there are no relevant fixed design standards, and there is no unified design method. There are great differences with the characteristics of the process flow or physical parameters, so the spiral wound tube heat exchanger The standardization process presents obstacles

There are many winding methods for the traditional spiral tube heat exchanger tube bundles, and there are many shortcomings. During the winding process, the tube spacing and layer spacing in the tube bundle cannot be guaranteed to be consistent everywhere, and the heat transfer effect is poor. There is no unified theoretical calculation method for computer-aided calculations. process

In addition, due to the large difference between the temperature of the low-temperature heat exchanger and the environment, the environment acts as a high-temperature heat source and continuously supplies heat to the low-temperature heat exchanger. The surface of the heat exchanger receives solar radiation, air convection heat transfer, environmental heat radiation or internal friction After being heated, the fluid inside the system, especially when heated by instantaneous high heat flux, will cause serious heat leakage, resulting in gas-liquid two-phase flow, and a large amount of superheated steam will be generated. The heat exchange process has a serious impact and brings great safety problems. However, it is difficult to meet the problem of heat exchange between the heat exchanger and the outside world under low temperature conditions by using the external capillary material insulation layer. The low temperature fluid in the heat exchanger Still undergoes a drastic phase transition process

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