Simulation and optimization of multi-component organic Rankine cycle integrated with post-combustion capture process

• We present an organic Rankine cycle utilizing multi component working fluid.
• Liquefied natural gas and waste heat of CO2 capture process are used for the cycle.
• Power generation is improved by working fluid recuperation and vapor recondensation.
• Thermal and 2nd law efficiencies are 30.3% and 46.2%, respectively.
• The power generation can reach 304 kJ per kg liquefied natural gas regasification.

A multi-component working fluid organic Rankine cycle (ORC) with advanced configuration is proposed and optimized in this paper. The proposed ORC utilizes the wasted heat of a CO2 capture process as a heat source, and waste heat utilization is optimized through heat integration. The ORC employs advanced configurations: multi component working fluid, a cold energy recuperating in multi stream cryogenic heat exchanger (MSCHE), and a vapor recondensation process (VRP), thus, its power generation efficiency is much higher than that of conventional ORCs that utilize wasted heat. Process optimization is achieved through exergy evaluation. The results indicate that the proposed cycle is able to produce 304 kJ per kg liquefied natural gas (LNG), and its corresponding second-law efficiency is approximately 46.2%. With the power generation of the ORC, the power de-rate caused by the CO2 capture process installation is completely compensated and produces more electricity compared with the original power plant.