Efficient co-production of power and ammonia from black liquor.

Black liquor (BL) is a by-product in the paper and pulp industry. Although it has good potential for providing energy as an industrial waste, BL's high moisture content limits its usability. In this study, an integrated system to effectively co-produce power and ammonia (NH 3) from BL is modeled and evaluated. The modeling and integration are conducted using the principles of exergy recovery and process integration to effectively circulate the energy/heat throughout the whole system. The developed system involves BL evaporation, gasification, syngas chemical looping (SCL), and NH 3 synthesis. During SCL process, H 2 , CO 2 , and N 2 -rich gas are produced consecutively in the oxidation, reduction, and combustion reactors, respectively. The designed system can achieve the total energy efficiency of ~50%. The result also suggests that N 2 -rich gas and pure H 2 produced during SCL can be used directly for NH 3 synthesis without any additional energy penalty. The additional step for CO 2 separation can also be avoided, affording a cleaner and more efficient system that provides complete carbon capture. • An efficient energy system of a H 2 production is proposed. • The system comprises evaporation, gasification, syngas chemical looping and NH 3 synthesis. • High energy efficiency in NH 3 production can be realized. • The designed system achieved about 50% of total energy efficiency. • The system has cleaner and more efficient system with 100% carbon capture. [ABSTRACT FROM AUTHOR]