Modeling of efficiently-integrated algal gasification, nitrogen production, ammonia synthesis, and power generation

Abstract

Abstract Novel integrated system to convert algae to NH3 is proposed with the objective of effective and thorough energy/heat circulation to achieve high total energy efficiency. The integrated system consists of hydrothermal gasification (HTG), chemical looping, N2 production, NH3 synthesis, and power generation. Algae are converted initially to syngas through HTG, which is further converted to CO2 and H2 in chemical looping module. The produced H2 from chemical looping module is reacted with the produced highly pure N2 to N2 production module to form NH3 in NH3 synthesis module. To realize high energy-efficiency, an enhanced process integration, consisting of exergy recovery and process integration, is applied. The energy/heat involved in the integrated system is recirculated thoroughly and partly used for power generation. From process modeling and calculation, the proposed integrated-system shows very high total energy efficiency up to about 70%, including NH3 production of 53% and power generation of 17%.