Simulation and Economic Optimization of Vapour Recompression Configuration for Partial CO2 capture

Abstract

A standard method for CO2 capture is by absorption in an amine based solvent followed by desorption. Such plants are traditionally designed for removal of 85-90 % CO2 from the exhaust gas as a reasonable trade-off between high removal efficiency and low investment. The major challenge is the high energy demand for CO2 desorption. In many industrial cases, a limited amount of cheap waste heat is available and this makes partial CO2 capture an interesting option. It is not obvious whether a high removal efficiency from a part of the exhaust or a low removal efficiency from the total exhaust is the optimum solution. In this work, simulations of traditional and vapor recompression processes are performed, and it is found that vapour recompression treating the total exhaust is energy optimum. A traditional process with a low absorption column treating the total exhaust gives the lowest cost per ton CO2 captured.