Thermodynamic and economic assessments of an innovative methane liquefaction and multigeneration process relying on coke oven gas flow and micro gas turbine cycle

In this paper, a novel system employing coke oven gas (COG) as the source of electricity, hydrogen, chilled water, hot water, and liquefied methane has been suggested and analyzed. A cryogenic separation module is incorporated into the suggested configuration for the recovery of the liquid methane content of the COG fuel. The remaining gas then feeds into a gas turbine cycle to produce electricity. Besides, the gas turbine cycle's waste heat recovery is accomplished by a steam Rankine cycle. The steam Rankine cycle's waste heat is also utilized to generate cooled water by an ammonia-water refrigeration cycle. A proton exchange membrane electrolyzer is provided with power and hot water from the integrated system for hydrogen production. Aspen HYSYS simulation tool is used to simulate the system and carry out an extensive economic, thermodynamic, and environmental analysis. The analysis indicates that the process's exergy efficiency equals 54.54 % and its overall energy efficiency equals 60.43 %, while the levelized cost of energy equals 0.06 $/kWh. A sensitivity analysis is also performed on some of the important parameters that are of interest in thermodynamic performance, including the steam turbine inlet pressure, gas turbine inlet temperature, ARC working fluid pressure, combustion air pressure and mass flow rate, stream 39 temperature, and hydrogen production flow rate. Remarkably, the sensitivity analysis shows increasing the temperature of the gas turbine's incoming air significantly increases the system's exergy and energy efficiency and reduces carbon dioxide emissions.