CN-121976251-A - Hot film coupling heavy water extraction method and system based on seawater electrolysis hydrogen production

CN121976251ACN 121976251 ACN121976251 ACN 121976251ACN-121976251-A

Abstract

The invention relates to a hot film coupling heavy water extraction method and system based on seawater electrolysis hydrogen production, and belongs to the technical field of seawater resource utilization. The method comprises the steps of pretreating natural seawater to obtain pretreated seawater, carrying out electrolytic treatment on the pretreated seawater by utilizing a PEM electrolytic unit, carrying out primary enrichment on deuterium in the pretreated seawater to form primary deuterium-enriched water while producing hydrogen, directly taking the primary deuterium-enriched water produced in the PEM electrolytic step as feed of a raw material side of a membrane separation unit, vaporizing the primary deuterium-enriched water in the membrane separation unit under the driving of heat of electrolytic sensible heat carried by the primary deuterium-enriched water, condensing light water on a condensing side through a separation membrane of the membrane separation unit, enriching heavy water on the raw material side to obtain secondary deuterium-enriched water, and rectifying the secondary deuterium-enriched water by utilizing a rectifying unit to obtain a heavy water product. The invention realizes the extraction of commercial grade heavy water under low energy consumption by effectively coupling PEM electrolysis, membrane method isotope screening and rectification, and has high heavy water enrichment efficiency.

Inventors

TANG BO
LI JIAWEI
YU QIANG
QIN JIANGUANG
CAI ZHENGWEI
CHENG YONGQIANG
QIAN ZEHUA

Assignees

崂山国家实验室

Dates

Publication Date: 20260505
Application Date: 20260120

Claims (9)

1. The method for extracting heavy water based on the thermal film coupling of the seawater electrolysis hydrogen production is characterized by comprising the following steps of: pretreatment, namely pretreating natural seawater to obtain pretreated seawater meeting the water inlet requirement of a PEM electrolysis unit; A PEM electrolysis step of carrying out electrolysis treatment by using the pretreated seawater as a feed of a PEM electrolysis unit so as to initially enrich deuterium in the pretreated seawater to form primary deuterium-enriched water while producing hydrogen, wherein the primary deuterium-enriched water is used as water produced by the PEM electrolysis unit and is discharged out of the PEM electrolysis unit together with sensible heat generated by electrolysis treatment; The primary deuterium-enriched water produced in the PEM electrolysis step is directly used as a raw material side feed of a membrane separation unit without heating treatment, in the membrane separation unit, the primary deuterium-enriched water is vaporized under the driving of the heat of electrolysis sensible heat carried by the primary deuterium-enriched water, light water enters a condensation side for condensation through a separation membrane with hydrogen isotope screening function of the membrane separation unit, and heavy water is enriched on the raw material side to obtain secondary deuterium-enriched water, wherein the temperature of the condensation side is lower than that of the raw material side; And a rectification step, namely taking the secondary deuterium-enriched water produced in the membrane separation step as a feed of a rectification unit, and rectifying the secondary deuterium-enriched water by utilizing the rectification unit so as to ensure that the heavy water content in the heavy component exceeds 99 percent, thereby obtaining a heavy water product.
2. The method for extracting heavy water by thermal membrane coupling based on seawater electrolysis hydrogen production according to claim 1, wherein in the PEM electrolysis step, the electrolysis treatment is performed at a temperature of 50-80 ℃ and a current density of 0.5-2.5A/cm 2 .
3. The method for extracting heavy water by thermal membrane coupling for hydrogen production based on seawater electrolysis according to claim 1 or 2, wherein in the PEM electrolysis step, a plurality of PEM electrolysis units are sequentially connected in series, the water produced by the previous PEM electrolysis unit is used as the feed of the next PEM electrolysis unit to enrich deuterium in seawater step by step, and the water produced by the last PEM electrolysis unit is used as the primary deuterium-enriched water.
4. A method for extracting heavy water based on thermal film coupling for producing hydrogen from seawater by electrolysis according to claim 3, wherein in the PEM electrolysis step, the temperature and current density of the plurality of PEM electrolysis cells are increased step by step.
5. The method for extracting heavy water by thermal membrane coupling based on seawater electrolysis hydrogen production according to claim 1, wherein in the membrane separation step, a plurality of membrane separation units are provided; the membrane separation units are sequentially connected in series, the raw material side enrichment liquid of the former-stage membrane separation unit is used as the raw material side feed of the next-stage membrane separation unit, and the raw material side enrichment liquid of the final-stage membrane separation unit is used as the second-stage deuterium-enriched water; Or a plurality of membrane separation units are connected in parallel, and the raw material side enrichment liquid of each membrane separation unit is collected and then used as the secondary deuterium enriched water.
6. The method for extracting heavy water by thermal membrane coupling for producing hydrogen based on seawater electrolysis according to claim 1, further comprising a reflux treatment step, wherein the reflux treatment step is characterized in that light components produced by rectification treatment of the rectification unit are taken as light component reflux liquid, the light component reflux liquid is taken as a feed of the raw material side of the membrane separation unit to repeatedly perform the membrane separation step, or the light component reflux liquid is taken as a feed of the PEM electrolysis unit to repeatedly perform the PEM electrolysis step.
7. A thermal membrane coupled heavy water extraction system for producing hydrogen based on electrolysis of seawater, characterized by being used for operating the thermal membrane coupled heavy water extraction method for producing hydrogen based on electrolysis of seawater according to any one of claims 1 to 6, comprising: the pretreatment unit is used for pretreating the natural seawater to obtain pretreated seawater meeting the water inlet requirement of the PEM electrolysis unit; a PEM electrolysis cell for electrolyzing the pretreated seawater to initially enrich deuterium in the pretreated seawater to form primary deuterium-enriched water while producing hydrogen; The membrane separation unit comprises a separation membrane with a hydrogen isotope screening function, wherein the separation membrane divides the inside of the membrane separation unit into a raw material side and a condensation side, the raw material side takes primary deuterium-enriched water produced by the PEM electrolysis unit as a feed, the primary deuterium-enriched water is gasified on the raw material side under the driving of the heat of electrolysis sensible heat carried by the primary deuterium-enriched water, light water enters the condensation side through the separation membrane to be condensed, and heavy water is enriched on the raw material side to obtain secondary deuterium-enriched water; And the rectifying unit is used for rectifying the secondary deuterium-enriched water produced by the membrane separation unit to obtain a heavy water product.
8. The seawater-based hydrogen-producing thermal membrane coupled heavy water extraction system of claim 7, wherein the PEM electrolysis cell is a plurality of the PEM electrolysis cells in series.
9. The thermal membrane coupled heavy water extraction system for producing hydrogen based on seawater electrolysis according to claim 7, wherein the membrane separation units are plural, and the plural membrane separation units are sequentially connected in series or in parallel.

Description

Hot film coupling heavy water extraction method and system based on seawater electrolysis hydrogen production Technical Field The invention belongs to the technical field of seawater resource utilization, and particularly relates to a method and a system for extracting heavy water based on thermal film coupling for hydrogen production by seawater electrolysis. Background Heavy water is used as an important strategic isotope resource and has an irreplaceable effect in the fields of nuclear energy, fine chemical engineering and the like. The existing industrial heavy water production mainly comprises an ammonia-hydrogen exchange method, a sulfide exchange method and a multistage rectification method, and the problems of complex flow, large equipment scale, high energy consumption, high operation cost and the like generally exist in the processes, and a special production system is usually required to be independently configured, so that the process is difficult to cooperatively operate with other energy processes. In recent years, along with the rapid development of proton exchange membrane electrolysis hydrogen production technology, the electrolysis methods such as PEM and the like can not only produce high-purity hydrogen, but also promote the deuterium abundance in water in the process of electrolysis hydrogen production due to the potential difference of heavy water and light water. For example, chinese patent No. 118461029A discloses an offshore platform PEM water electrolysis hydrogen production and heavy water production system, which adopts two-stage PEM electrolysis to realize the extraction of heavy water while producing hydrogen, but the deuterium content in the PEM electrolysis produced water is still relatively low, and high-concentration heavy water is difficult to obtain only by adopting an electrolysis mode, and the patent is further combined with a rectification mode, so that the heavy water in the PEM electrolysis produced water is further purified by utilizing rectification. However, since deuterium content in PEM electrolyzed produced water is still relatively low, rectification extraction is directly performed, and great energy consumption is required in the rectification stage to enable the heavy water content to exceed 99% so as to meet the commercial grade heavy water requirement. Therefore, how to extract commercial grade heavy water by utilizing the enrichment effect of electrolytic seawater hydrogen production on deuterium under low energy consumption is a technical problem to be solved currently. Disclosure of Invention Aiming at the technical problems, the invention provides a hot film coupling heavy water extraction method and a hot film coupling heavy water extraction system based on seawater electrolysis hydrogen production, which realize the extraction of commercial heavy water with low energy consumption through effective coupling of PEM electrolysis, membrane method isotope screening and rectification and have high heavy water enrichment efficiency. The invention provides a hot film coupling heavy water extraction method based on seawater electrolysis hydrogen production, which comprises the following steps: pretreatment, namely pretreating natural seawater to obtain pretreated seawater meeting the water inlet requirement of a PEM electrolysis unit; A PEM electrolysis step, namely taking pretreated seawater as a feed of a PEM electrolysis unit, carrying out electrolysis treatment on the pretreated seawater by using the PEM electrolysis unit so as to initially enrich deuterium in the pretreated seawater to form primary deuterium-enriched water while producing hydrogen, wherein the primary deuterium-enriched water is taken as water produced by the PEM electrolysis unit, and the primary deuterium-enriched water is discharged out of the PEM electrolysis unit together with sensible heat generated by the electrolysis treatment; The membrane separation step, namely directly taking primary deuterium-enriched water produced in the PEM electrolysis step as feed of the raw material side of a membrane separation unit under the condition of not carrying out heating treatment, vaporizing the primary deuterium-enriched water in the membrane separation unit under the drive of the heat of electrolysis sensible heat carried by the primary deuterium-enriched water, enabling light water to enter a condensation side for condensation through a separation membrane with a hydrogen isotope screening function of the membrane separation unit, and enriching heavy water on the raw material side to obtain secondary deuterium-enriched water, wherein the temperature of the condensation side is lower than that of the raw material side; And a rectification step, namely taking the secondary deuterium-enriched water produced in the membrane separation step as a feed of a rectification unit, and rectifying the secondary deuterium-enriched water by utilizing the rectification unit so as to ensure that the heavy