【Ten Years of Rapid Development in Chemical Equipment】New technologies for producing hydrogen from seawater while generating fresh water were developed successfully between 1278 and 2023
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Recently, the team led by Deng Dehui, a researcher at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and Liu Yanting, an associate researcher, has developed a new technology for producing hydrogen and generating fresh water simultaneously using seawater as a raw material, in response to the needs associated with offshore/onshore wind power for hydrogen production. Using this technology, they conducted testing and validation on a 25-kilowatt-scale device. The electrical energy utilization rate for traditional alkaline electrolysis of water to produce hydrogen is generally between 65% and 80%; the unutilized electrical energy is converted into waste heat and released into the environment, resulting in severe waste of energy. In this study, the team utilized the waste heat generated by water electrolysis as a heat source for desalinating seawater at low temperatures. They developed a waste heat recovery system and integrated it with low-temperature seawater desalination technology to create a new technique for producing hydrogen from seawater while simultaneously generating fresh water. Compared to traditional freshwater electrolysis for hydrogen production, this technology eliminates the heat exchanger units required for waste heat removal, as well as the cooling medium associated with them, thereby reducing equipment costs and energy consumption. On this basis, the team developed a 25-kilowatt seawater-to-hydrogen with fresh water co-production system, utilizing the self-developed armored catalyst integrated electrode. The operation results show that using seawater as the raw material, it is possible to carry out efficient electrolytic water splitting to produce hydrogen while generating fresh water as a by-product; the hydrogen production capacity can reach 3 tons per year, with a purity of ≥99.999%. In addition to meeting the needs for electrolysis itself, an additional 6 tons of fresh water can be produced each year. At the same time, compared with traditional freshwater electrolysis hydrogen production systems, it can increase the electrical energy utilization efficiency of alkaline electrolysis hydrogen production systems by over 10%, demonstrating the feasibility and advancement of the new technology for hydrogen production from seawater along with freshwater generation.
Xie Heping’s team: Direct hydrogen production from seawater without desalination. In June 2023, a pilot test was successfully conducted in the Fuzhou area for the technology of producing hydrogen through direct electrolysis of seawater without the need for desalination, developed jointly by Dongfang Electric Group and Academician Xie Heping’s team from the Chinese Academy of Engineering. This approach eliminates the need for seawater desalination, allowing hydrogen to be produced directly from complex, non-desalted seawater; it represents a breakthrough in the research and industrialization of hydrogen production from seawater. The successful sea trial of this project achieved for the first time an integrated technical system for combining offshore wind renewable energy with direct hydrogen production from seawater ； It also verified for the first time the feasibility of direct hydrogen production from offshore wind power without desalination, capable of withstanding marine environmental interference. It uses a polytetrafluoroethylene membrane (similar to a semipermeable membrane) to separate the high-concentration KOH electrolyte in the alkaline electrolyzer from seawater, and takes advantage of the difference in vapor pressure between the two (similar to a concentration difference) to achieve automatic penetration and replenishment of water from seawater into the KOH electrolyte. Meanwhile, ions and impurities in seawater remain in the seawater itself, thus creating an automatic mechanism for seawater purification and water replenishment. This technology essentially amounts to adding a pressure difference-driven automatic water replenishment system to the auxiliary system of the alkaline electrolyzer; the water source is changed from ordinary purified water to seawater with a slightly higher concentration, thereby creating an electrolyzer that combines seawater purification with alkaline hydrogen production. No major technical modifications are required inside the alkaline electrolyzer itself. At the same time, there is no additional energy consumption required for seawater purification, which means that the total energy consumption of this electrolyzer is similar to that of industrial alkaline electrolyzers. Currently, the Dongfu Research Institute under Dongfang Electric has signed a project cooperation agreement with China National Petroleum Corporation’s Changqing Oilfield Branch, to apply the technology for producing hydrogen through in-situ direct electrolysis of undesalinated seawater at the Changqing Oilfield. This is the first time this technology has been applied to the production of hydrogen from industrial wastewater, following its successful pilot testing at sea. In the future, the project aims to expand seawater hydrogen production technology to the field of energy conservation and environmental protection, providing a reference framework for producing hydrogen from industrial wastewater such as petrochemical wastewater and steelmaking wastewater.
【Sea and River Safety Discussion Thread】A compilation post; updates will be made regularly – feel free to discuss! https://bbs.hcbbs.com/thread-5497581-1-1.html (Source: Haichuan Chemical Industry Forum)
Well done; success lies in the details.