【Major Industrial Equipment in the Chemical Industry】China’s first 90MPa liquid-driven piston hydrogen compressor for hydrogen refueling stations, 2022

Two years ago, Xi’an Jiaotong University and the People’s Government of Sichuan Province signed a strategic cooperation agreement aimed at leveraging their respective strengths and integrating resources effectively to carry out in-depth collaboration in areas such as strategic decision-making consultation, technological innovation and achievement transformation, as well as talent exchange and training. Building on years of cooperation, Sichuan Dachuan Compressor Co., Ltd. and Xi’an Jiaotong University reached an agreement to jointly establish the \"Sichuan Dachuan-Xi’an Jiaotong University Hydrogen and Fuel Cell Vehicle Compressor Research Center.\" Focusing on the fields of hydrogen energy and fuel cell vehicles, this center will work on developing key technologies and new products related to hydrogen compressors for hydrogen refueling stations, health management systems for such stations, air compressors for hydrogen fuel cell vehicles, and hydrogen circulation systems. The successful development of a 90MPa liquid-driven piston hydrogen compressor for hydrogen refueling stations is the result of the in-depth collaboration between Sichuan Dachuan and Xi’an Jiaotong University within the framework of their provincial-university strategic partnership.

In 2004, under the guidance of the provincial and Ziyang municipal authorities, Chuanya Press Factory completed its restructuring. After the restructuring, Huaxi General Machinery was divided into two entities: Sichuan Lianzhong Petrochemical Machinery Equipment Co., Ltd. and Sichuan Dachuan Compressor Co., Ltd. Lianzhong Company took on the bad assets and debts of the former Chuanya Press Factory; it is essentially a shell company ； Ookawa Company acquired all of the high-quality assets and current assets from the former Kawakami Press Plant, entering the market with a lean structure. After the restructuring, Ookawa Company had seven or eight hundred employees, with those who remained being mainly the key personnel in management, technology, and production.

“At present, 500-kilogram, 35MPa compressors are still the most commonly used in hydrogen refueling stations in China. However, two trends are becoming increasingly evident: one is the rising demand for 70MPa hydrogen refueling stations, and the other is the increased use of high-flow hydrogen refueling stations. For compressors, this means that high pressure and large displacement will be the trends in their development. ”An industry insider said as much. At the same hydrogen storage volume, higher pressure means a longer driving range and better fuel efficiency for the vehicle; data shows that 70MPa hydrogen provides a 67% longer driving range compared to 35MPa hydrogen. At the same time, as hydrogen-powered commercial vehicles become more widespread, the best way to enable hydrogen refueling stations to serve large fleets on limited construction land is to increase the displacement of the compressors. Under this trend, many companies are developing or have already launched high-pressure, high-displacement compressors. Among the diaphragm compressor suppliers, Zhongding Hengsheng has introduced compressors with a pressure of 90 MPa. Its project to produce 1,000 diaphragm compressors per year, including 100 units of 90 MPa hydrogen diaphragm compressors per year, has passed the environmental impact assessment and is set to begin production soon. Fengdian Jinkaiwei has currently, in collaboration with the Beijing Low-Carbon Clean Energy Research Institute of the **Energy Group, developed China’s first diaphragm compressor for hydrogen refueling stations with a high discharge capacity of 90 MPa that has passed hydrogen-related tests; its performance exceeds the requirements set for this project. East German Industry has also currently launched 90MPa diaphragm compressor products. Among the suppliers of liquid-driven compressors, Hydralisson has designed high-displacement liquid-driven compressors tailored to the actual needs of high-density commercial hydrogen refueling stations. These compressors feature a large discharge volume per unit, strong adaptability to inlet pressures, and high outlet pressures. The 90MPa liquid-driven piston compressor and intelligent integrated system for mobile hydrogen refueling stations, jointly developed by Sichuan Dachuan Compressor Company and Xi’an Jiaotong University, have been successfully developed recently.

Typical projects for hydrogen station construction over the past six months show a clear increase in skid-mounted hydrogen station projects and integrated hydrogen production and refueling station projects. For example, CIMC Enrico has recently developed and deployed the second-generation compact skid-mounted 35MPa hydrogen refueling unit in Foshan. This unit is designed for use in scenarios where hydrogen is required, such as port terminals, internal material handling operations, and fuel cell vehicle manufacturing plants, providing hydrogen refueling for hydrogen-powered forklifts, test vehicles, and operational vehicles. Another example is from April this year, when the largest hydrogen fuel cell supply project in South China – the Sinopec Maoming Petrochemical Hydrogen Fuel Cell Supply Center – was successfully completed and entered the production preparation phase. The project includes a hydrogen purification unit with a capacity of 3,000 standard cubic meters per hour, a hydrogenation master station (phase 1) with a capacity of 500 kilograms per day, and associated units. Once the project is put into operation, it will be able to produce 6,400 kilograms of high-purity hydrogen per day, supplying markets within a 200-kilometer radius. Given that the National Development and Reform Commission has explicitly called for the exploration of new models for hydrogen refueling stations that integrate hydrogen production, storage, and refueling within the medium- to long-term plan for the development of the hydrogen industry, and considering that provinces such as Guangdong, Shanghai’s Lingang area, and Chengdu in Sichuan have already introduced relevant policies and standards to accelerate the construction of demonstration hydrogen production and refueling stations, it is foreseeable that the use of hydrogen compressors for station operations will increase in specific applications in the future.

Among the three technical approaches used in hydrogen refueling stations – diaphragm compressors, liquid-driven compressors, and ion compressors – ion compressors are less widely used in China at present due to their high cost, and because the products of companies other than Linde are not yet fully developed. However, these compressors offer advantages such as compact design, high efficiency, no pollution, and the ability to generate high pressure and large flow rates, which makes them considered as the \"next generation of products\". Among the more commonly used diaphragm compressors and liquid-driven compressors, diaphragm compressors are currently favored due to their higher level of technical maturity, better sealing performance, more stable quality control, and higher efficiency. It is worth noting that, amid the trend toward larger displacement capacities, liquid-driven compressors are gaining increasing attention in the past two years. This is due to their advantages in terms of displacement, as well as features such as modular design, relatively small size, easy maintenance, and long-lasting seals. Tomorrow, Fei *Chao, the manager of the H2 Energy Jinan hydrogen refueling station, told Gao Gong Hydrogen Power that the two technical approaches are suitable for different application scenarios and do not actually conflict with each other. Diaphragm compressors have significant advantages, and liquid-driven compressors also have suitable application scenarios; we are keeping an eye on liquid-driven compressors as well, and we wouldn’t rule out adopting this technology in appropriate situations.