Integrated liquid hydrogen production technology with cascade separation and waste heat&cooling energy utilization

Hydrogen energy is of great significance for building a clean, low-carbon, and efficient energy landscape and achieving the "dual carbon" goals. This paper put forward a coalbed methane reforming based liquid hydrogen manufacture scenario through process enhancement of comprehensive separation and external energy utilization. The new separation process combines pressure swing adsorption (PSA), membrane, and MEA absorption technology to achieve efficient hydrogen concentration and CH4 recovery, while capturing CO2. The utilization of flue gas waste heat and liquefied natural gas (LNG) cooling energy significantly reduces energy consumption. Process simulation, heat integration and tech-economic analysis are successively carried out to run through and assess the superiority of the whole system. Results indicate that for the plant with annual productivity of 42.35 kilotons, its unit liquid hydrogen cost is 2.75 $/kg, energy consumption is 23.74 kW h/kg and the carbon emission is 11.56 kg/kg. The current system can recover 209.07 tons of carbon dioxide and 33.48 tons of methane annually. Therefore, this work provides a promising liquid hydrogen generation technology for future application.