Low carbon methanol production through electrification and decarbonization

Abstract

Electrifying and decarbonizing the industrial sectors are important candidate strategies towards enhancing sustainability. This work introduces a novel superstructure-based framework of an integrated system to produce low-carbon methanol via electrification and decarbonization. The building blocks include a methanol plant, CO₂ capture and recycle process, solar photovoltaics (PV) modules, wind turbines, reverse osmosis, and electric boilers. The hybrid renewable energy sources of solar and wind are included to provide electric power to the entire system units while connecting to a power grid to address the diurnal fluctuations of solar and wind energy. Stranded natural gas (SNG) is used as a raw material since it is an abundant resource that is not effectively useable due to physical and economic constraints. An industrial electric boiler is considered to supply steam, heating, and cooling requirements to the methanol process. CO₂ released from methanol production process is captured and recycled to reduce the environmental impact of the methanol production process. A reverse osmosis plant (RO) is employed to treat local wastewater from the SNG production and provide clean water for methanol production. An Eagle Ford site in Texas is selected as a case study. A comprehensive techno-economic analysis (TEA) and an environmental evaluation demonstrate the capability of the proposed system to produce low-carbon methanol. A multi-period mixed integer nonlinear program (MINLP) is solved to find the optimal mix of solar energy, wind energy, and local power grid to attain the maximum net annual profit. The Optimal solution was found at solar at 87.65% and wind at 12.35% with a return on investment (ROI) of 11.07%, and the payback period (PBP) is 7.6 years.