Numerical Studies On Natural Gas Power Plant With LNG Cold Energy Applied To Oxy-combustion

Energy crisis and Environmental pollution are the products of human society development. Economic development model of resource consumption has brought a huge problem to the human living environment. Scholars have sought various methods to increase energy utilization efficiency and reduce emissions of pollutants. By improving combustion efficiency,cascade utilization of industrial waste heat and LNG cold energy utilization etc. to improve energy utilization efficiency; through the use of clean energy such as natural gas etc. the application of carbon capture and storage or other means to reduce emissions of pollutants. Oxy-combustion technology has been deemed one of the promising techniques of carbon capture and storage technology,which has a large energy conservation space.On the basis of previous studies,this paper proposes a novel oxy-fuel power plant integration system with LNG cold energy. The integrated system consists of “Air separation subsystem with LNG cold energy”, “Power generation subsystem in oxy-combustion with H2 O under high pressure” and “Carbon capture subsystem with high-pressure liquid oxygen”. Similar to most of the Oxy-combustion, the system also consists of three parts, they are air separation unit?ASU?,carbon capture unit and thermal power generation system respectively. Working fluid of Most of the existing Oxy-combustion systems are the CO₂ in flue gas. Due to the condensation condition of CO₂ are relatively harsh, the condensation process of lots of CO₂ will increases the costs. Therefore,the system loop used H2 O as the working fluid. In addition, air separation unit of the integrated system with LNG cold energy as an auxiliary, simultaneously cryogenic cold energy of liquid oxygen and liquid nitrogen are applied to process of carbon capture and air separation unit respectively,which reduced the energy consumption of air separation unit and process of carbon capture. This paper modeled the process of integrated systems with Aspen Plus software, simulated operating conditions of each subsystems and analyzed the effects of the main factors, thereby determining the optimization principle.By optimizing the operation conditions of the integrated system,obtained the carbon capture rate up to 100%,realized zero carbon emissions. Simultaneously with the introduction of LNG cold energy and the utilization of the cold energy of liquid oxygen and nitrogen,in the case of completing process of air separation for oxygen and carbon capture, the gross power generation efficiency, the net power generation efficiency and energy efficiency of the integrated system are 64.74%,55.52% and 60.90%,respectively. The integrated system are more superior compared with conventional air combustion system and general oxy-fuel system.