CN-121720270-B - Cold end positive para-hydrogen reaction/heat exchanger of refrigerator

CN121720270BCN 121720270 BCN121720270 BCN 121720270BCN-121720270-B

Abstract

The invention belongs to the technical field of heat exchange equipment, and particularly discloses a positive and secondary hydrogen reaction/heat exchanger at a cold end of a refrigerator, which comprises a heat exchanger body relatively fixed with a cold head of the refrigerator, wherein one end of the heat exchanger body is provided with a containing groove which is used for containing the cold head of the refrigerator and can be in contact with heat exchange, and the peripheral side of the heat exchanger body is provided with a positive and secondary hydrogen reaction/heat exchange channel circumferentially arranged around the containing groove. The normal para-hydrogen reaction/heat exchanger provided by the invention can realize high-efficiency heat exchange and normal para-hydrogen conversion of hydrogen in a low-temperature environment of a refrigerator, and is suitable for low-temperature applications such as liquid hydrogen preparation, storage and transportation.

Inventors

DU YUBIN
CAO JINGJING
WU YINGZHE
Qian Die
JIANG WEI

Assignees

上海科安创能科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260225

Claims (6)

1. The positive-secondary hydrogen reaction/heat exchanger at the cold end of the refrigerator comprises a heat exchanger body which is used for being thermally connected with the cold head of the refrigerator, and is characterized in that one end of the heat exchanger body is provided with a containing groove which is used for containing the cold head of the refrigerator and can exchange heat with the cold head of the refrigerator; the heat exchanger body is elastically fixed with the cold head of the refrigerator through a suspender; The positive secondary hydrogen reaction/heat exchange channel is a circuitous structure formed by sequentially connecting a plurality of sub-channels axially arranged along the heat exchanger body, and the sub-channels are uniformly distributed along the circumferential direction of the heat exchanger body; The heat exchanger body includes: the core heat exchange component is provided with the accommodating groove and the sub-runners, and an opening structure is arranged at the joint of the top ends or/and the bottom ends of two adjacent sub-runners; the upper sealing cover or/and the lower sealing cover for sealing the opening structure are/is realized, and the upper sealing cover or/and the lower sealing cover are provided with a filling opening of the normal para-hydrogen reaction catalyst corresponding to the corresponding opening structure and a sealing piece for sealing the filling opening.
2. The cold-end normal-para-hydrogen reaction/heat exchanger of a refrigerator according to claim 1, wherein one end of the hanger rod is elastically fixed with the heat exchanger body by an elastic reset member.
3. The cold end normal para-hydrogen reaction/heat exchanger of a refrigerator according to claim 2, wherein the elastic reset piece is a hanger rod spring sleeved at the bottom of the hanger rod; The heat exchanger body is provided with a lifting lug with a positioning hole; the bottom end of the suspender penetrates through the positioning hole, and the end of the suspender is simultaneously provided with an adjustable positioning piece for axially limiting the suspender spring.
4. The cold-end normal-para-hydrogen reaction/heat exchanger of a refrigerator according to claim 1, wherein the normal-para-hydrogen reaction/heat exchange channels are two arranged in parallel and are symmetrically arranged around the circumference of the accommodating groove.
5. The cold-end normal-para-hydrogen reaction/heat exchanger of a refrigerator according to claim 1, wherein the heat exchanger body is provided with an inlet and an outlet communicated with the normal-para-hydrogen reaction/heat exchange channel, and the inlet and the outlet are provided with filters.
6. The refrigerator cold end normal para-hydrogen reaction/heat exchanger according to claim 1, wherein the normal para-hydrogen reaction/heat exchange channel is filled with normal para-hydrogen reaction catalyst at the same time.

Description

Cold end positive para-hydrogen reaction/heat exchanger of refrigerator Technical Field The invention relates to heat exchange equipment, in particular to a structure and a connection mode of a normal para-hydrogen reaction/heat exchanger arranged at a cold end of a refrigerator. Background Hydrogen contains two isomers, para-hydrogen (p-H 2) and ortho-hydrogen (o-H 2) due to the different spin directions. At normal temperature, the ratio of para-hydrogen to ortho-hydrogen in the equilibrium hydrogen is about 1:3 (i.e., 25% para-hydrogen, 75% ortho-hydrogen). As the temperature decreases, the normal parahydrogen balance ratio changes significantly. The interconversion process between orthohydrogen and para-hydrogen does not involve the cleavage and formation of chemical bonds, nor changes the chemical nature of the hydrogen molecule, essentially a process of nuclear spin rearrangement, accompanied by a change in the rotational energy level of the molecule. Since nuclear spin inversion is a quantum mechanical "forbidden" process, the rate of spontaneous conversion is extremely slow. At the liquid hydrogen temperature, the para-hydrogen ratio can reach 99.8 percent. If hydrogen gas (75% normal hydrogen) produced at room temperature is liquefied directly, the normal hydrogen is spontaneously converted slowly to para-hydrogen in a liquid hydrogen storage tank and conversion heat is released. This heat of conversion, which is much greater than the latent heat of vaporization of the liquid hydrogen, can result in substantial boiling and vaporization of the liquid hydrogen, resulting in significant losses. Therefore, the conversion of the normal and secondary hydrogen is accelerated by the normal and secondary hydrogen catalyst in the hydrogen liquefaction process, and the conversion heat is taken away in the liquefaction process, so that the liquid hydrogen with the secondary hydrogen content of more than 95% is obtained, and the liquid hydrogen can be stably stored. Patent document CN117168087a proposes a solution for achieving hydrogen liquefaction by providing low-temperature refrigeration using a standard refrigeration unit. Wherein, a hydrogen pipeline is arranged in the cold end of the standard refrigeration unit and is used for cooling hydrogen, and a part or all of the hydrogen pipeline is provided with a normal para-hydrogen catalyst. The hydrogen line with the catalyst section constitutes the normal para-hydrogen reactor. The patent application also states that the standard refrigeration unit is a recuperative refrigerator, which may be specifically a Gifford-McMahon refrigerator, a stirling refrigerator, a solvin refrigerator, a GM-type pulse tube refrigerator or a stirling-type pulse tube refrigerator. Prior art solution US20170205140A1 provides a tube-cartridge heat exchanger (see fig. 9) for a small-sized hydrogen liquefaction system, in which the heat exchanger 24 is formed by directly winding a tube 24b around a cylinder 24a, and then connecting the heat exchanger 24 to the bottom end surface of the cold head of the refrigerator through the end surface of the cylinder 24a, which has a series of technical problems. (1) The thermal contact resistance on the thermal conduction path is large, and in the design, two thermal contact resistances exist on the thermal conduction path from the bottom end face of the refrigerator cold head to the cooled hydrogen in the tube 24b, namely, the bottom end face of the refrigerator cold head is contacted with the end face of the tube 24a, and the side face of the tube 24a is contacted with the surface of the tube 24 b. The contact thermal resistance between solid interfaces at low temperature is the main thermal resistance source for heat conduction and exchange. (2) The heat exchange area is insufficient, namely the contact between the copper pipe and the surface of the cylinder body cannot fully utilize the whole outer surface of the copper pipe, the whole heat exchanger 24 is connected with the end surface of the bottom of the cold head of the refrigerator, and the heat exchange area of the side surface of the cylinder body of the cold head of the refrigerator is not fully utilized; (3) The hydrogen has limited heat exchange efficiency, and the heat transfer efficiency is further affected by adopting a simple copper pipe structure and being incapable of forming internal turbulent flow due to single flow in the pipe; (4) The optimization space is small, namely the optimization of the heat exchanger in the form of a round copper pipe can be limited to a certain extent, and the heat exchange efficiency can be improved only by increasing the number of winding turns, but the length of the cylinder 24a can be increased, so that the material cost is increased rapidly, and the weight of the heat exchanger is increased rapidly; (5) Partial condensation cannot be effectively eliminated, namely, when hydrogen flows in the heat exchange tube, partial condensation is caused