A novel methanol and electricity cogeneration system based on coal and biomass complementary gasification technology: Comprehensive analysis of thermodynamic, carbon emission, and economic performance

Currently, methanol production primarily relies on fossil fuels, presenting the disadvantage of low energy efficiency and high carbon emissions. Developing low-carbon, highly efficient, and economically feasible methanol synthesis solutions has become a critical issue that requires urgent resolution. This research proposes a cogeneration system for methanol and electricity utilizing a novel coal and biomass complementary gasification technology. The integrated system is expected to enhance thermodynamic efficiency and reduce carbon emission intensity through the synergistic effect of coal and biomass during the gasification process. Furthermore, the novel system can improve performance through the recovery of the syngas sensible heat, the chemical energy of the purge gas, and enhanced thermal integration. This research experimentally investigates the co-pyrolysis and gasification characteristics of coal and biomass, and establishes the simulation model using Aspen Plus software to evaluate the system performance in terms of thermodynamics, carbon emissions, and economic feasibility. The results indicate that the cold gas efficiency of the novel gasification process is 14.01 % higher than that of the coal-water slurry gasification process and 11.04 % higher than that of biomass gasification technology, confirming that the novel gasification method can significantly enhance gasification efficiency and methanol yield. The energy efficiency of the new system reaches 56.97 %, representing improvements of 14.06 % and 17.94 % over coal-to-methanol and biomass-to-methanol systems, respectively. The novel system achieves negative carbon emissions with a carbon intensity of −2.15 kg/MWh. Additionally, the levelized cost of methanol is 294.98$/t, representing reductions of 19.42 % and 45.45 % compared to coal-to-methanol and biomass-to-methanol systems, respectively.