Separation and recovery of carbon dioxide by a membrane flash process utilizing waste thermal energy

Abstract The membrane flash process utilizing waste thermal energy was developed to realize an energy-saving technology and to substitute it for a conventional regenerator. The operating conditions of a membrane flash at high temperature were studied. The DEA concentration and the flashing pressure had optimum values to improve the performance and reduce the energy consumption for CO 2 recovery. The petroleum refinery process and iron manufacturing process were proposed for candidate processes that actually had waste energy sources. Energy consumption and costs for CO 2 recovery in the membrane flash and chemical absorption were estimated by custom-made program and discussed under the same conditions. The membrane flash was suitable for the CO 2 emission sources that had high CO 2 concentration independently of the plant scale. The chemical absorption was suitable for large-scale sources, even if the CO 2 concentration was low.