A Novel Multifunctional Energy System for CO₂ Removal by Solar Reforming of Natural Gas

In this paper, a novel multifunctional energy system (MES) fueled by natural gas and solar radiation is proposed. In this MES, hydrogen and electricity are cogenerated and approximately 92% of CO₂ derived from natural gas is removed. The solar concentrated process provides high-temperature thermal energy to the methane/steam reforming reaction. The resulting syngas enters a pressure swing adsorption unit to separate approximately 80% of hydrogen. This process significantly increases the concentration of carbon dioxide in syngas from nearly 19% to 49%, which decreases energy consumption in CO₂ removal. As a result, the overall power efficiency of the new system becomes about 39.2%. Compared to a conventional natural gas-based hydrogen plant with CO₂ removal and a concentrated solar power tower plant, the overall power efficiency of the new system is increased by 7.9 percentage points. Based on the graphical exergy analysis, the integration of synthetic utilization of natural gas and solar radiation, combination of the hydrogen production plant and power plant, and integration of the energy utilization processes and CO₂ separation were found to play significant roles to improve thermodynamic performance. The result obtained here provides a new approach for highly efficient use of solar radiation by hybrid natural gas.