CN-121977327-A - High-pressure low-energy consumption hydrogen liquefaction system and method

CN121977327ACN 121977327 ACN121977327 ACN 121977327ACN-121977327-A

Abstract

The invention relates to a high-pressure low-energy consumption hydrogen liquefaction system which comprises a high-pressure raw material hydrogen supply unit, a precooling subsystem and a liquefaction subsystem, wherein the high-pressure raw material hydrogen supply unit is used for supplying high-pressure raw material hydrogen, the precooling subsystem is used for carrying out preliminary cooling on the high-pressure raw material hydrogen, the precooling subsystem is used for further cooling and liquefying the precooled high-pressure raw material hydrogen, the system is configured to expand the high-pressure raw material hydrogen cooled by the precooling subsystem and then cooled to be close to a critical temperature by a part of the liquefaction subsystem so as to reduce the consumption of external cold energy in the hydrogen liquefaction process and further reduce the hydrogen liquefaction energy consumption, the core problems of high energy consumption and high cost of the existing hydrogen liquefaction are accurately solved by recovering the pressure potential energy of the precooled high-pressure raw material hydrogen and converting the pressure potential energy into the cold energy back-feeding liquefaction process without additional input energy to obtain cold energy, the liquefaction energy consumption and comprehensive cost are reduced, the high-pressure raw material characteristics of the hydrogen for water electrolysis hydrogen are adapted, the high-pressure raw material characteristics of hydrogen can be perfectly connected to the upstream of the hydrogen storage and transportation, and the economical and large-scale application potential of the hydrogen is improved.

Inventors

WANG ZHIPING
LI ANRAN
WANG QIAN
KAN SUYU
WANG SHAOGANG
GONG LINGHUI

Assignees

中山先进低温技术研究院

Dates

Publication Date: 20260505
Application Date: 20260204

Claims (10)

1. A high pressure low energy consumption hydrogen liquefaction system, comprising: a high-pressure raw material hydrogen supply unit for supplying high-pressure raw material hydrogen; the pre-cooling subsystem is used for primarily cooling the high-pressure raw material hydrogen; the liquefaction subsystem is used for further cooling and liquefying the precooled high-pressure raw material hydrogen; The system is configured to expand the high-pressure raw material hydrogen cooled by the precooling subsystem and then cooled by the partial liquefying subsystem to be close to the critical temperature, release the pressure potential energy of the high-pressure raw material hydrogen and convert the high-pressure raw material hydrogen into cold energy, supplement the cold source requirement of the liquefying subsystem by utilizing the cold energy, reduce the consumption of external cold energy in the hydrogen liquefying process, and further reduce the hydrogen liquefying energy consumption.
2. The high-pressure low-energy-consumption hydrogen liquefaction system according to claim 1, wherein the high-pressure raw material hydrogen supply unit comprises an electrolyzed water hydrogen production device, and the raw material hydrogen pressure output by the electrolyzed water hydrogen production device is not lower than 3MPa.
3. The high pressure low energy consumption hydrogen liquefaction system of claim 1, wherein the pre-cooling subsystem is a mixed working medium refrigeration cycle.
4. The high pressure low energy consumption hydrogen liquefaction system of claim 1, wherein the liquefaction subsystem is an inverted brayton cycle or claude cycle circuit employing helium or hydrogen as a refrigerant.
5. The high pressure low energy consumption hydrogen liquefaction system of claim 4, wherein the liquefaction subsystem comprises a plurality of refrigeration modules connected in series, each refrigeration module comprising a turbo expander and a corresponding heat exchanger for progressively cooling the feed hydrogen.
6. The high-pressure low-energy-consumption hydrogen liquefaction system according to claim 5, wherein a positive-secondary hydrogen conversion catalyst is filled in a heat exchanger of at least one stage of the refrigeration module, and is used for realizing positive-secondary hydrogen conversion in the cooling process and guaranteeing the liquefaction efficiency.
7. The high pressure low energy consumption hydrogen liquefaction system of claim 1, wherein the expansion process is accomplished by at least one turboexpander disposed within the liquefaction subsystem for expanding and cooling the partially cooled high pressure feed hydrogen.
8. The high pressure low energy consumption hydrogen liquefaction system of claim 7, wherein the turboexpander is disposed between a temperature zone for cooling the feed hydrogen from 34K to 20K.
9. The high-pressure low-energy-consumption hydrogen liquefaction system according to claim 5, wherein an independent flow regulating device is arranged in each stage of the refrigeration module and is used for independently regulating the flow of the refrigeration working medium entering the turbine expander of the stage according to the temperature of the material at the outlet of the corresponding heat exchanger, so as to optimize the refrigeration energy consumption.
10. The high-pressure low-energy consumption hydrogen liquefaction method is characterized by comprising the following steps of: providing high-pressure raw material hydrogen with the pressure not lower than 3 MPa; precooling the high-pressure raw material hydrogen; further cooling and liquefying the precooled high-pressure raw material hydrogen; And in the further cooling process, the high-pressure raw material hydrogen which is subjected to partial cooling is expanded and cooled, so that the pressure potential energy of the high-pressure raw material hydrogen is converted into cold energy, and the external cold energy consumption required by hydrogen liquefaction is reduced.

Description

High-pressure low-energy consumption hydrogen liquefaction system and method Technical Field The invention relates to the technical field of liquid hydrogen production, in particular to a high-pressure low-energy-consumption hydrogen liquefying system and method. Background The hydrogen energy is used as a clean and efficient secondary energy, becomes a key carrier for connecting renewable energy and a terminal energy use scene, and has gradually matured upstream and downstream industries, namely, industrial hydrogen technologies such as upstream water electrolysis hydrogen production (especially renewable energy water electrolysis hydrogen production), downstream fuel cell application, synthetic ammonia alcohol and the like are all realized on a large scale. However, the hydrogen resource distribution in China presents obvious regional characteristics that a large amount of renewable energy electricity hydrogen production base and industrial byproduct hydrogen productivity are concentrated in a resource enrichment area, and obvious space mismatch exists between the renewable energy electricity hydrogen production base and a load center with dense population and vigorous energy consumption requirements, so that an economic and efficient hydrogen storage and transportation technology becomes a core clamping point for restricting the large-scale development of hydrogen energy. The current mainstream hydrogen storage and transportation technology has obvious limitations that the economic transportation distance of the high-pressure gas hydrogen storage and transportation technology is usually not more than 200km, large-scale storage faces a large safety risk, the pipeline hydrogen transportation has the advantage of transportation economy, but only solves the problem of 'transportation' and cannot meet the large-scale storage requirement of hydrogen, and the organic liquid hydrogen storage can improve the transportation efficiency, but has extremely high equipment investment and process energy consumption in the hydrogen absorption and dehydrogenation links, and is only suitable for special scenes without dehydrogenation at the tail end. In contrast, after the hydrogen is liquefied into liquid hydrogen, the density can reach 780 times of the hydrogen in an standard state, the storage and transportation efficiency can be greatly improved, the unit storage and transportation cost is reduced, and the method is a core technical path for large-scale hydrogen energy transregional allocation and long-period storage. However, the economical efficiency of liquid hydrogen storage and transportation is severely limited by the high cost of the hydrogen liquefaction link, for the liquid hydrogen storage and transportation scene of 1000km level, the hydrogen liquefaction cost accounts for more than 85% of the storage and transportation cost of the whole life cycle of the liquid hydrogen, and in the liquefaction cost composition, the energy consumption cost accounts for more than 60%, so that the reduction of the hydrogen liquefaction energy consumption becomes a key break for improving the economical efficiency of the liquid hydrogen storage and transportation and promoting the large-scale application of the hydrogen energy. In order to solve the problem of overhigh hydrogen liquefaction energy consumption, the prior art has explored various optimization paths, wherein part of schemes adopt mixed working medium refrigeration cycle to reduce heat transfer temperature difference, part of schemes improve cold energy utilization rate through modes of multi-stage composite refrigeration cycle, cold energy coupling recovery and the like, and the schemes utilize Liquefied Natural Gas (LNG) cold energy to replace the traditional precooling process to simplify the system structure. However, the technologies still have obvious limitations that means such as mixed working medium optimization become industry knowledge, only have slight difference in working medium proportion, have insufficient technical innovation, partial schemes are used for reducing heat transfer temperature difference by increasing heat transfer area, energy consumption is reduced at the cost of greatly increasing equipment investment cost, economy is unbalanced, the technologies such as LNG cold energy coupling depend on specific resource conditions, applicable scenes are limited, and main stream hydrogen source scenes mainly for hydrogen production by renewable energy source electrolyzed water are difficult to adapt. Notably, none of the prior art has exploited the energy saving potential starting from the pressure characteristics of the feed hydrogen itself. The current renewable energy source water electrolysis hydrogen production becomes the main flow direction of future hydrogen sources, wherein the pressure of raw material hydrogen output by a proton exchange membrane electrolyzer can reach more than 7MPa, and the hydrogen production has considerable pressur