Thermodynamic and environmental analyses of a hydrogen-enriched natural gas oxy-fuel combustion power plant

Abstract

Hydrogen-enriched natural gas is regarded as a promising low-carbon fuel in clean energy field. A hydrogen-enriched natural gas oxy-fuel combustion power plant is established to study the effect of hydrogen content on system thermodynamic performance. Three different diluents including recycled flue gas (RFG), H2O, and CO2 are used to moderate the high combustion temperature. The transcritical CO2 cycle is adopted to efficiently utilize flue gas waste heat. As the hydrogen blending ratio increases from 0 to 0.5, the efficiency of the O2/RFG system, O2/H2O system and O2/CO2 system increases by 1.45%, 1.13% and 1.16%, respectively. The RFG system is preferable to realize high efficiency that can reach 50.23%. In the proposed systems, the carbon capture rate (CCR) decreases while specific CO2 emission (SECO2) increases with the hydrogen addition. In O2/RFG system, the CCR reaches a minimum of 99.09% when SECO2 is 3.81. The study results can have a positive influence on the utilization of hydrogen energy.