2019 Alfian 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, hydrogen 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 between economic and environmental considerations. The aim of this work was to propose a green urea production strategy using a multi-objective optimization (MOO) model to minimize production costs and environmental impacts by considering the future 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 production costs and greenhouse gas emissions, compared to conventional urea production. 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.