Simulation and 4E analysis of a novel multigeneration process based on carbon dioxide capture and utilization, water electrolyzer, and COG reforming

Abstract

Current study presents a novel integrated process for cogeneration of methanol (37020 kg/h), heating (25730 kgLPS/h), oxygen (1000 kmol/h), and desalinated water (29.83 m3/h) from polluting resources, including flue gas and coke oven gas (COG). Concerning carbon dioxide (CO2) capture and utilization concept, COG reforming, and generating hydrogen from an electrolyzer, the newly designed configuration is available. The other subsystems of the proposed structure include seawater desalination unit, steam power plant, methanol production unit, and ammonia power plant. Thermodynamic outcomes demonstrate that the total energetic and exergetic efficiencies equal 58.71% and 69%, correspondingly. Also, the total destructed exergy is 135311 kW, where the COG steam reforming subsystem has the major share (29%). Subsequently, total CO2 emission, net CO2 emission, and the intensity of the CO2 emission of this configuration are respectively found at 32970 kg/h, −7395.71 kg/h, and −0.1998 kgCO2/kgMeOH. Based on the economic evaluation, the cost rate of yielded methanol equals 0.351 $/kg, which exhibits a significant decrease compared to other structures. Concerning the sensitivity study, it is found that enhancing the desorption column’s reflux ratio results in decreasing the total CO2 emission. In addition, increasing the feedwater of the electrolyzer, due to the rise in the CO2 conversion, is one of the important factors in growing the total energetic efficiency and methanol production, as well as decreasing the net CO2 emission of the process.