Concept design and techno-economic performance of hydrogen and ammonia co-generation by coke-oven gas-pressure swing adsorption integrated with chemical looping hydrogen process

The coke-oven gas direct chemical looping hydrogen generation is a promising process for chemical industry; however, it still suffers from high energy consumption and low hydrogen production. The chemical looping derived H-2 and N-2 can be used to produce ammonia. Therefore, a new process for coke-oven gas chemical looping hydrogen and ammonia co-generation integrated with pressure swing adsorption technology, which can flexibly adapt to market demand, is proposed in this paper. The new process has two extreme configurations to produce hydrogen or ammonia only. A thorough analysis of key operational parameters of the proposed systems has been conducted to optimize coke -oven gas utilization, and maximize hydrogen and subsequent ammonia production. The maximal hydrogen and ammonia productions are 7126 and 4784 kmol/h of 5532 kmol/h coke oven gas consumption for the two extreme configurations, respectively. Moreover, an exergy efficiency of 68.5-73.6% and about 100% direct CO2 capture efficiency are obtained when switching between hydrogen and ammonia production in the novel process. These values are compared to those of the coke-oven gas chemical looping hydrogen generation process (hydrogen production of 6613 kmol/h per 6276 kmol/h coke-oven gas consumption, 66.0% exergy efficiency, and 73.3% CO2 capture efficiency). Finally, the economic and sensitive analyses of the novel process are also conducted in this paper.