Membrane Cascade Type of «Continuous Membrane Column» for Power Plant Post-Combustion Carbon Dioxide Capture Part 1: Simulation of the Binary Gas Mixture Separation

The present paper deals with the complex study of CO₂ capture from combined heat power plant flue gases using the efficient technological design of a membrane cascade type of «Continuous Membrane Column» for binary gas mixture separation. In contrast to well-known multi-step or multi-stage process designs, the cascade type of separation unit provides several advantages. Here, the separation process is implemented in it by creating two counter current flows. In one of them is depleted by the high-permeable component in a continuous mode, meanwhile the other one is enriched. Taking into account that the circulating flows rate overcomes the withdrawn one, there is a multiplicative increase in separation efficiency. A comprehensive study of CO₂ capture using the membrane cascade type of «Continuous Membrane Column» includes the determination of the optimal membrane material characteristics, the sensitivity study of the process, and a feasibility evaluation. It was clearly demonstrated that the proposed process achieves efficient CO₂ capture, which meets the modern requirements in terms of the CO₂ content (≥95 mol.%), recovery rate (≥90%), and residual CO₂ concentration (≤2 mol.%). Moreover, it was observed that it is possible to process CO₂ with a purity of up to 99.8 mol.% at the same recovery rate. This enables the use of this specific process design in CO₂ pretreatment operations for the production of high-purity carbon dioxide.