Poultry litter valorization by application of hydrothermal gasification: Process simulation, Economic, Energic, and Environmental analysis

Hydrothermal gasification (HTG) at supercritical water has been used to convert poultry litter into value-added products. In this research study, a process simulation model of HTG for syngas from poultry litter has been developed using Aspen Plus software, and it has been validated at four distinct temperature levels. The effects of the three parameters, including temperature, pressure, and biomass concentration on syngas quality and net heat steam have been analyzed. The results show that the model has a better yield of hydrogen and methane gas with a superior lower heating value (LHV) at 540°C, 25 MPa, and 20% feedstock concentration. Feedstock concentration is the biggest contributing factor in the production of hydrogen. Energy analysis of the HTG has been carried out using the Sankey diagrams technique, which shows that the energy efficiency of this process is about 61%. Similarly, an economic analysis of the process has been conducted based on heat steam production costs, and it reveals that the HTG method is at least 10% cost-effective than coal, natural gas, or distillated oil. In comparative results of life cycle assessment (LCA) with the HTG process and direct land disposal, the HTG process has outperformed direct land disposal. Therefore, the outcomes of this study suggest that this process is economical, environmentally friendly, and energy efficient as compared to direct land disposal.