Study on supersonic swirling condensation characteristics of CO2 in Laval nozzle

Abstract

Supersonic swirl separation technology has been widely used in natural gas processing and has achieved good results. However, there are few studies on the application of supersonic separation technology to the removal of CO2 from natural gas, and the condensation rule of CO2 under supersonic swirling flow condition is still unclear. In order to study the supersonic swirling condensation characteristics of CO2 in Laval nozzle, the Euler mathematical model of the condensation flow of CO2–CH4 two-component mixed gas was established, and the feasibility of CO2 removal by supersonic separation technology was verified by numerical simulation. The results show that, in the process of axial flow and swirling flow, the variation trend of CO2 condensation parameters is basically the same along the axial direction of the nozzle, but the distribution of parameters is significantly different along the radial direction. The increase of swirl intensity will increase the nozzle's liquefaction efficiency and reduce the working flow of the nozzle. The inlet temperature and inlet pressure had a significant influence on the liquefaction efficiency of the nozzle, while the inlet CO2 content had little influence on the liquefaction efficiency.