Experimental and numerical study on the offshore adaptability of new FLH2 floating hydrogen liquefaction production storage and offloading unit

With the development of hydrogen production technology from offshore wind power and natural gas, the deep-sea energy interconnection system using hydrogen energy as the medium is constantly improving. The floating hydrogen liquefaction production storage and offloading unit (LH2-FPSO, FLH2) is an effective method for large-scale utilization of offshore hydrogen energy. By filling the heat exchanger with ortho-parahydrogen conversion catalyst, a new porous medium heat exchange channel is formed. Integrating the spiral wound heat exchanger with the ortho-parahydrogen catalytic conversion reactor can reduce the deck area of FLH2 process system and lower the investment cost of floating hydrogen liquefaction device. The performance of FLH2 can be influenced by the offshore wave and typhoon. In this paper, the methods of floating cryogenic visualization experiment, theoretical analysis and numerical simulation are conducted to study the coupled flow and heat transfer mechanism of working fluid applied in FLH2 under offshore conditions. The results show that the sea state has little influence on the ortho-parahydrogen conversion and cooling process of hydrogen in the porous heat exchange tube. The complex flow and heat transfer challenges brought by the integrated process of new floating hydrogen liquefaction and ortho-parahydrogen conversion have been overcome. With the effect of co-current shear of gas-phase mixed refrigerant, a large dry area will not appear on the outer wall surface of porous tube under offshore conditions. The FLH2 process system shows good adaptability at sea.