Production & Technology

Multi-objective optimization of green urea production


The availability of natural gas as feedstock for nitrogen fertilizer production continues to decline, while its price increases, encouraging the search for renewable feedstocks for the future green urea industry. Renewable feedstocks include waste biomass, hydro- gen from solar PV-electrolysis, and the combination of these feedstocks with natural gas. The selection of a green production strategy is a critical step in the trade-off be- tween economic and environmental considerations. The aim of this work was to pro- pose a green urea production strategy using a multi-objective optimization (MOO) model to minimize production costs and environmental impacts by considering the fu- ture cost development of technologies and feedstock price for each technology in the time frame of 2020-2050. The results show that green urea production can reduce pro- duction costs and greenhouse gas emissions, compared to conventional urea produc- tion. Biomass gasification technology fulfills the minimum requirements for production cost and CO2 emissions from 2020 to 2035 and combined biomass gasification-PV electrolysis without battery technology is the optimum process from 2040 to 2050.