Performance analysis, techno-economic and life cycle assessment of Jatropha curcas L. (Euphorbiaceae) seedcake gasification and Fischer-Tropsch integrated process for biomethanol production

Abstract

The overall economic performance of biodiesel production can be improved by reducing the cost of methanol required for the transesterification process. Gasification integrated with Fischer- Tropsch synthesis provides an alternative route to biomass conversion. In this study, a thermodynamic model of steam gasification of Jatropha curcas L. (Euphorbiaceae) seedcake and Fischer- Tropsch synthesis of the syngas is developed to forecast the production of bio-methanol using Aspen Plus. The combined effects of the gasification temperature, steam flow rate, and off-gas recycling percentage were investigated using a response surface methodology to pinpoint the optimal operating conditions. The results showed that a gasification temperature of 820 C, steam flow rate of 740 kg/h and off-gas recycle fraction of 0.6 were the optimum operating conditions for producing the highest amount of bio-methanol (53.13 wt.%). An initial capital investment of 7.4 million dollars and a minimum production price of bio-methanol of $0.91/L was determined. Integrating the bio-methanol production process in biodiesel plants reduces the cost of producing biodiesel by 26.36%. The environmental impact analysis showed that the process had an overall effect of 10 potential environmental impacts/kg of bio-methanol generated. Utilizing optimized process parameters may improve the process’ competitiveness on a commercial scale and improve sustainability in the biorefinery process.