Parametric Analysis of a Novel Cryogenic CO₂ Capture System Based on Stirling Coolers

Abstract

CO(2) capture and storage (CCS) is an important alternative to control greenhouse gas (GHG) effects. In previous work, a novel desublimation CO(2) capture process has been exploited making use of three free piston Stirling coolers (namely, SC-1, SC-2, and SC-3, respectively). Based on the developed system, moisture and CO(2) in the flue gas can condense and desublimate in the prefreezing and main-freezing towers, respectively. Meanwhile, the storage column is chilled by SC-3 to preserve the frosted CO(2), and permanent gas (such as N(2)) passes through the system without phase change. The whole process can be implemented at atmospheric pressure and reduce the energy penalty (e.g., solvent regeneration and pressure drop) in other technologies. In this work, the influence of process parameters has been investigated in detail. The optimal conditions for the system are as follows: idle operating time is 240 min, flow rate is 5 L/min, vacuum degree of the interlayer is 2.2 × 10(3) Pa, and temperatures of SC-1, -2, and -3 are -30, -120, and -120 °C, respectively. Under these conditions, the energy consumption of the system is around 0.5 MJ(electrical)/kg CO(2) with above 90% CO(2) recovery.