CO2 Capture from Off-shore Gas Turbines Using Supersonic Gas Separation

CO2 capture from gas turbine based off-shore application face challenges such as size (foot-print), weight and stability (wave motion) in addition to the challenges faced by on-shore industry. Space- and weight challenges are given priority, and the size of the capture installations will be of importance when selecting capture technology rather than process efficiency alone. In this work, CO2 capture from an FPSO turbine exhaust gas using a supersonic separator is investigated. To assess the operational performance of the capture process, a Laval nozzle (converging- diverging geometry) model is implemented and successfully integrated in a steady-state process flow sheet simulator. The model includes equilibrium thermodynamics describing freeze-out of dry ice from a gas mixture containing CO2. To determine under which conditions this process is thermodynamically and fluid dynamically feasible, different boundary conditions are explored. By integrating the supersonic separator unit in a flow sheet model, the interaction between the capture and the rest of the process is studied. The results indicate that supersonic expansion is a viable strategy for capturing CO2 from off-shore gas turbines.