Efficiency Analysis of Hydrogen Internal Combustion Engine Power Generation System Based on Organic Hydrogen Storage Solution

Organic solution is an ideal hydrogen storage and transport carrier, and the dehydrogenation of solution is an endothermic process. High dehydrogenation heat demand becomes a key factor restricting its application. Hydrogen internal combustion engine (HICE) is an ideal power device under the current background of emphasizing clean and low carbon. In this study, dibenzyltoluene (DBT) was selected as liquid organic hydrogen carrier (LOHC), the residual heat of engine exhaust was used as the heat source of organic solution dehydrogenation, and the residual heat of engine exhaust is used as the heat source of organic solution dehydrogenation, using the combustion of dehydrogenated hydrogen products to supplement the heat absorption of hydrogen released by organic solution. Taking hydrogen internal combustion engine power generation as the application scenario, the power generation system of liquid organic hydrogen storage solution combined with hydrogen internal combustion engine (LOHC-HICE) is designed and the system calculation model is built. The system efficiency changes and the influence of subsystem modules on the system during the transfer of hydrogen internal combustion engine from 800 to 2000 are comprehensively analyzed. Waste heat accounted for about 20% of the heat consumed in dehydrogenation, up to 26% at 2000 RPM. Hydrogen combustion energy was the main contributor to dehydrogenation heat, accounting for 60-70%. Comprehensive and comparative analysis was made on measures to improve waste heat utilization, such as improving heat exchange efficiency, increasing exhaust temperature and reducing reaction temperature, and it was concluded that controlling reaction temperature at a lower level was the most feasible. The benefits to the system are most obvious. Improving the process of dehydrogenation of compressed hydrogen and organic solution and reducing the reaction temperature are the key to maintain self-dehydrogenation in the practical application of hydrogen combustion engine.