Thermoeconomic analysis of a novel zero-CO2-emission high-efficiency power cycle using LNG coldness

Abstract: This paper presents a thermoeconomic analysis aimed at the optimization of a novel zero-CO2 and other emissions and high-efficiency power and refrigeration cogeneration system, COOLCEP-S (Patent pending), which uses the liquefied natural gas (LNG) coldness during its revaporization. It was predicted that at the turbine inlet temperature (TIT) of 900°C, the energy efficiency of the COOLCEP-S system reaches 59%. The thermoeconomic analysis determines the specific cost, the cost of electricity, the system payback period and the total net revenue. The optimization started by performing a thermodynamic sensitivity analysis, which has shown that for a fixed TIT and pressure ratio, the pinch point temperature difference in the recuperator, ΔT p1, and that in the condenser, ΔT p2 are the most significant unconstrained variables to have a significant effect on the thermal performance of novel cycle. The payback period of this novel cycle (with fixed net power output of 20MW and plant life of 40years) was ∼5.9years at most, and would be reduced to ∼3.1years at most when there is a market for the refrigeration byproduct. The capital investment cost of the economically optimized plant is estimated to be about 1000$/kWe, and the cost of electricity is estimated to be 0.34–0.37CNY/kWh (∼0.04$/kWh). These values are much lower than those of conventional coal power plants being installed at this time in China, which, in contrast to COOLCEP-S, do produce CO2 emissions at that. [Copyright &y& Elsevier]