Configuration Analysis of a Novel Zero CO₂ Emission 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can be achieved at a temperature much lower than ambient, and high-pressure liquid CO₂ ready for disposal can be withdrawn from the cycle without consuming additional power.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 thermal and exergy efficiencies of a base-case cycle are found to be over 65% and 50% respectively, which can be increased up to 68% and 54% when reheat is used. Cycle variants incorporating reheat, intercooling, and reheat+intercooling, as well as no use of LNG coldness, are also defined and analyzed for comparison. The approximate heat transfer area needed for the different cycle variants is also computed. Besides electricity and condensed CO₂, the byproducts of the plant are H₂O, liquid N₂ and Ar.