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Simulation Study On The High-efficiency Power Generation System In Oxy-fuel Combustion Natural Gas Power Plant

Posted on:2021-08-05Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiangFull Text:PDF
GTID:2492306104488904Subject:Heating, Gas Supply, Ventilation and Air Conditioning Engineering
Abstract/Summary:PDF Full Text Request
With the increasing demand for energy and the urgent need for CO2 emission reduction,it is imperative to achieve carbon capture in the power industry.The cold energy released by the LNG gasification process can be used in the oxy-fuel combustion carbon capture power plant to offset the energy penalty of oxy-fuel combustion technology.The integration of gas turbine and efficient thermal cycles is used to achieve the maximum recovery of the flue gas waste heat.Finally,the efficiency of the power plant can be effectively improved.This paper proposes an original natural gas oxy-fuel combustion generation system,which combines LNG cold energy utilization with O2/H2O oxy-fuel combustion technology.The integration of gas turbine and two-stage power generation subsystems is used to realize the full utilization of flue gas waste heat in the power plant.Supercritical CO2 regenerative cycle and supercritical CO2 recompression cycle is applied as the primary power generation subsystem.In the study of the secondary power generation subsystem,the cycle performance of organic Rankine cycle and transcritical CO2 cycle in the low-grade power generation is compared.In this work,Aspen Plus software is applied to model the system.The influences of temperature,pressure and other factors on the subsystem’s performance are analyzed.Thermodynamic analysis and economic evaluation are carried out on the power generation system in this paper.The result of research shows that the cycle efficiency of the supercritical CO2recompression cycle is higher than that of the supercritical CO2 regenerative cycle.However,the net power output of the recompression cycle is lower than that of the regenerative cycle.In the end,different forms of supercritical CO2 cycle layout have little effect on the overall performance of the power generation system.In the field of low-temperature waste heat power generation,the performance of the transcritical CO2cycle is significantly better than that of the organic Rankine cycle,which can efficiently recover the sensible heat and rich latent heat resources in the low-temperature flue gas,so the transcritical CO2 cycle is selected as the secondary power generation subsystem.The numerical results show that when 94.8%of CO2 with 97.2%purity is captured,the power consumption of carbon capture is 0.07 k Wh/kg-CO2.When the supercritical CO2regenerative cycle is used as the primary subsystem,the thermal efficiency of the integrated system is 53.1%,the exergy efficiency is 39.1%,and the unit net power output cost is 649¥/k W,which is 0.1%,0.2%and 1.23%lower than that of the integrated system using supercritical CO2 recompression cycle,respectively.
Keywords/Search Tags:Oxy-fuel combustion, LNG cold energy, Supercritical CO2 cycle, Organic Rankine cycle, Transcritical CO2 cycle, Energy conservation and emission reduction
PDF Full Text Request
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