(213g) Numerical Simulation on the Feasibility of Bulk CO€2 Separation in Natural Gas via Supersonic Nozzle Expansion System

The application of supersonic nozzle separator has been proven for dehydration and hydrocarbon dew pointing.  A study was conducted on the potential of the nozzle supersonic expansion technology for CO₂ separation from natural gas. A proof of concept testing of the nozzle prototype is being validated via a multiphase flow loop. The setup consists of a multiphase pump, gas-liquid separators and heat exchangers. Pressure transducers were installed along the nozzle prototype and the pressure reading is recorded by the data acquisition system. Besides pressure, the temperature inlet, primary and secondary outlets of the tube were also monitored. Two vibration sensors were installed to monitor the effect of the high vibration to the prototype. An on-line gas chromatography was installed at the inlet and the outlet of the nozzle tube to monitor the inlet composition and the effect of the phase separation occurred in the tube to the outlet composition. The pressure profile plotted along the prototype was compared with the CFD simulation result and significant flow of liquid CO₂ was produced during the test. The result of temperature reduction at the nozzle outlet shows that the thermodynamic prediction on gas expansion using de-Laval nozzle was proven as per simulation. The outcome from the experiment provides the improvements to the CFD simulation numerical modelling as well as the in-house coding for CO₂ separation efficiency.