A novel near-zero CO2 emission thermal cycle with LNG cryogenic exergy utilization

A novel liquefied natural gas (LNG) fueled power plant is proposed, which has virtually zero CO2 and other emissions and a high efficiency. Natural gas is fired in highly enriched oxygen and recycled CO2 flue gas. The plant operates in a quasi-combined cycle mode with a supercritical CO2 Rankine-like cycle and a CO2 Brayton cycle, interconnected by the heat transfer process in the recuperation system. By coupling with the LNG evaporation system as the cycle cold sink, the cycle condensation process can be achieved at a temperature much lower than ambient and high-pressure liquid CO2 ready for disposal can be withdrawn from the cycle without consuming additional power. The net energy and exergy efficiencies are found to be over 65 and 50%, respectively. In the case computed (but not optimized), the required total heat exchanger area is estimated to be about 460 m2/MW electricity produced. Besides electricity and condensed CO2, the byproducts of the plant are H2O, liquid N2 and Ar.