Experimental investigation of low temperature CO2 liquefaction and phase-separation for carbon capture.

A low-temperature CO2 liquefaction and phase-separation experimental rig has been built in SINTEF's Thermal Energy laboratory in Trondheim for investigation of carbon capture and CO2 liquefaction applications. This paper describes the experimental setup and results from the first experimental runs. The rig has been operated with two different binary feed compositions; 63 mol% CO2 - 37 mol% N2, and 76 mol% CO2 - 24 mol% N2. These compositions are representative of a flue gas stream from for example a cement
factory after an initial membrane based bulk separation of the flue gas. The experimental results have been compared to steady-state equilibrium process simulations. These are found to be in close agreement with each other for process conditions, liquid CO2 product purity and Carbon Capture Ratio. Liquid CO2 product purity can be controlled by controlling the separation pressure in the second separator. Reduced separation pressure leads to increased CO2 product purity. The process is found to be stable and easily controllable.