Change in physical parameters of CO2 exhaust gas containing impurities from purification plant and selection of state equation
Due to the physical property difference among CO2,natural gas,and oil,CO2 pipeline transport is greatly different from natural gas and oil transport.Therefore,it is of great significance to study the physical property state parameters of CO2exhaust gas containing impurities from purification plants for CO2 pipeline transport in the gas phase.Firstly,this paper collected and analyzed the research cases of CO2 transport in China and abroad and found that phase state and physical property testing of CO2containing impurities is the basic condition for studying CO2 transport.Then,the exhaust gas from the purification plant was captured after hydrodesulfurization treatment,and the characteristics of the exhaust gas components from the purification plant before and after treatment were obtained.Through the preparation of fluid samples with different CO2 contents,flash test,and PV relationship test,the compression factor and density of CO2,as well as other physical property parameters under different temperatures and pressures were obtained.It is concluded that under the same pressure,higher CO2 content indicates a smaller compression factor.Under the same pressure,except for pure CO2,higher CO2 content indicates higher density,which is related to the content of C2 and other hydrocarbon components.At the same temperature,higher CO2 content contributes to higher viscosity under the same pressure,and the pressure gets lower as viscosity growth slows down.At the same temperature,higher CO2 content indicates higher specific heat at constant pressure.With the decrease in temperature,the CO2 content reaching the highest specific heat at constant pressure gradually decreases.Finally,BWRS,PR,and SRK state equations are used to calculate the compression factor,density,viscosity,and specific heat at constant pressure of the gas mixture with molar compositions of 50%CO2 and 100%CO2.Compared with the experimental results,the PR equation is selected as the most suitable state equation to guide the parameter setting of key nodes of CO2 transport in the gas phase.
CO2 containing impurityphysical parameterstate equationrelative error
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