Thermodynamic Analysis of A Novel Solar Hybrid System incorporating Methane Steam Reforming and A Recuperative Direct-fired Supercritical Carbon Dioxide Cycle

摘要

To achieve the zero emission for fossil-based power generation and advance the utilization of solar energy, a novel solar hybrid system integrating methane steam reforming and a recuperative direct-fired supercritical carbon dioxide (sCO_2) power cycle was proposed and analysed. In the proposed system, the concentrated solar energy is used to drive the methane steam reforming to be converted into the stable chemical energy in the syngas; then, the produced syngas is combusted with high-purity oxygen to drive a semi-closed sCO_2 power cycle with intensive heat recuperation and near-zero emission. Through introducing solar heat into the power cycle at the fuel side by reforming reaction, the methane consumption is greatly reduced and the main thermodynamic parameters are similar with the reference system without solar penetration, meaning the solar integration at fuel side has less effect on the operation parameters in the power cycle. Also, the system can operate flexible in response to the solar energy variability by storing the surplus syngas. The thermodynamic analysis results showed that, the proposed solar hybrid system can save 10.8% of methane consumption and the net system efficiency reaches 42.6%, 0.4 percentage points higher than the reference system, revealing the solar penetration can improve the system thermodynamic performance. From the perspective of solar energy utilization, the solar contribution ratio is 10.0% and the solar-to-electricity efficiency soars to 26.7%. The proposed concept may provide a science and technology foundation for efficient utilization of both fossil fuel and solar energy in an advance zero emission power cycle.