Process Simulation of Green Ammonia Production Via Sorption-Enhanced Gasification of Biomass

Abstract

Ammonia is a crucial hydrogen carrier. This paper explores small-scale green ammonia production from two-stage sorption-enhanced gasification of biomass. ASPEN Plus was used to calculate the mass and energy balance of two novel process designs; configuration (a) employs fractional flue gas recycling to supply nitrogen for producing carbon-neutral ammonia without air separation, and configuration (b) uses air separation to produce carbon-negative ammonia by efficiently capturing CO2. The mass balance shows that the ammonia yield of configuration (a) is about 5% higher than that of configuration (b). The energy analysis shows that additional biomass fed to the combustor is the primary energy penalty in configuration (a), while the primary energy penalty in configuration (b) is from the electricity consumption by the ASU and CO2 compressor. The energy penalty for configuration (a) is considerably higher than that for configuration (b); hence, configuration (b) has lower energy consumption.(36.4 GJ/t NH3 vs. 40.2 GJ/t NH3). Overall, configuration (b) is superior to configuration (a) from a techno-environmental standpoint.