Clean and energy-efficient hydrogen production and storage from coal

Clean conversion technologies of coal to hydrogen and its storage are proposed, compared and evaluated in this study. Chemical looping is selected as the main conversion technology to convert the fuel to both carbon dioxide and hydrogen. In addition, integrated system for hydrogen production from coal employing two different chemical looping methods were modeled and compared. The first system integrates coal drying, gasification, syngas chemical looping, hydrogenation, and power generation. On the other hand, the second system combines coal drying, direct chemical looping, hydrogenation, and power generation. Each proposed system was developed based on the principles of enhanced process integration technology, which is combining exergy recovery and process integration. The total energy efficiency of each integrated system is compared. From the study, it is shown that adoption of direct chemical looping, instead of gasification and syngas chemical looping, in the integrated system can improve the total energy efficiency significantly. In addition, it also represents high economic and technical feasibilities due to fewer numbers of required equipment.