Double-pipe heat exchanger used for small molten-salt heat-storage system

Abstract

The invention provides a double-pipe heat exchanger used for a small molten-salt heat-storage system. The double-pipe heat exchanger used for the small molten-salt heat-storage system comprises a plurality of double-pipe heat exchanger passes, end sealing flanges, flange end covers, and connecting pieces through which the double-pipe heat exchanger passes are connected. Each double-pipe heat exchanger pass comprises a hollow inner heat exchanger tube (7) and a hollow outer heat exchanger tube (5), wherein the inner heat exchanger tube (7) is arranged in the outer heat exchanger tube (5) in a sleeved mode; the inner heat exchanger tube (7) is filled with a heat-exchange medium; the space between the outer heat exchanger tube (5) and the inner heat exchanger tube (7) is filled with a coolingmedium; the two ends of each outer heat exchanger tube (5) are fixed to the outer surface of the inner heat exchanger tube (7) through the corresponding end sealing flanges; and the flange end coversare arranged on the outer sides of the end sealing flanges. According to the double-pipe heat exchanger used for the small molten-salt heat-storage system, the problem that the flow rate of molten salt in part of molten-salt heat-storage systems is too low is specifically solved through the flexible configuration of the double-pipe heat exchanger, the heat transfer efficiency is effectively improved, and the scaling risk is lowered; and the number of the heat exchanger passes can be increased, so that flexible configuration is achieved, and the media can be completely discharged automatically.

Description

technical field [0001] The field of thermal energy engineering of the present invention specifically relates to a casing heat exchanger applied to a small molten salt heat storage system. Background technique [0002] In the existing small-scale molten salt heat storage system, the molten salt exchanges heat with water through a shell-and-tube heat exchanger to generate steam or high-temperature water under pressure, and then heats the user through heat exchange between steam or high-temperature water under pressure and circulating water. Due to the strong heat storage capacity of molten salt and the large temperature drop before and after heat exchange, the flow rate of molten salt on the side of the heat exchanger tube is often too slow, resulting in low heat exchange efficiency and easy scaling, especially in some small heat storage systems. The amount is too small to even meet the design conditions of the heat exchanger. Molten salt is highly permeable and prone to tube...

AI Technical Summary

Problems solved by technology

Due to the strong heat storage capacity of molten salt and the large temperature drop before and after heat exchange, the flow rate of molten salt on the side of the heat exchanger tube is often too slow, resulting in low heat exchange efficiency and easy scaling, especially in some small heat storage systems. The amount is too small or even unable to meet the design conditions of the heat exchanger

Molten salt is extremely permeable, which is prone to tube sheet leakage in shell and tube heat exchangers

In addition, due to the deflection of the heat exchange tubes in the shell-and-tube heat exchanger, it is easy to accumulate molten salt, which is not conducive to the exhaustion of molten salt and may cause tube blockage

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