Exergy regeneration in an O_2/CO_2 gas turbine cycle with chemical recuperation by CO_2 reforming of methane

摘要

This paper proposes a novel power cycle system composed of a chemical recuperative cycle with CO_2-NG (natural gas) reforming and an ammonia absorption refrigeration cycle in which the heat is recovered from the turbine exhaust to drive the CO_2-NG reformer firstly, and then, lower temperature heat from the turbine exhaust is provided for the ammonia absorption refrigeration system to generate chilled media, which is used to cool the turbine inlet gas except for the exported part. Based on 1 kg s~(-1) of methane feedstock, the turbine inlet temperature of 1573 K and the CO_2 compressor outlet pressure of 1.01 MPa, the simulation results show that the new cycle system reached the net electric power production of 24.444 MW, the power generation efficiency of 48.9% based on the low heating value, the export chilled load of 1.070 MW and the exergy efficiency of 47.3%. On the other hand, 2.743 kg s~(-1) of liquid CO_2 was captured, which achieved the goal of zero CO_2 emission. Especially, we investigate the exergy regeneration performances of the chemical recuperation with CO_2-NG reforming, the lower temperature heat from the turbine exhaust generated chilled load and inlet cooling by the aid of the energy utilization diagram to expose the thermodynamic principle of energy integration for high efficiency power conversion in the system.