Environmental benefits analysis based on life cycle assessment of rice straw-based synthetic natural gas in China

A cradle-to-gate life cycle assessment of rice straw-based synthetic natural gas (R-SNG) production was carried out in this study, and the inventories of rice straw cultivating and harvesting, feedstock transportation, R-SNG facility construction and dismantling, and power consumption (i.e. purchased electricity (PE) scheme and self-supply power (SP) scheme) stages were analyzed. Then, the inventory data was characterized and normalized. The results showed that the SP scheme can significantly reduce the environmental impacts of R-SNG product. A comparison of R-SNG, natural gas (NG) and coal-based synthetic natural gas (C-SNG) was conducted from the perspective of environmental impacts. The results showed that the amount of CO2 emission from C-SNG was the largest, followed by that from NG, while the amount of CO2 emission from R-SNG was negative. A sensitivity analysis about allocation principles of the rice straw and rough rice was carried out to evaluate the allocation principles on the environmental impacts. In conclusion, R-SNG showed great environmental benefits in the abiotic resources saving and greenhouse gases emission reduction.