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.