(11h) Process Development of Novel Sub-Ambient Membrane Processes for CO2 Capture

CO₂/N₂ selectivity of membrane in the sub-ambient conditions is significantly increased, which allows considerable savings in energy consumption for membrane-based CO₂ capture process. In order to fully utilize benefits of high selectivity, we proposed novel membrane systems such that energy efficiency is maximized with full appreciation of capability in membrane for CO2 removal from coal-fired flue gas. The membrane process is configured to allow cost-effective use of membrane modules as well as energy-efficient generation of sub-ambient operating conditions through external refrigeration cycles. Enhancement of CO2 capture performance is made with the strategic use of gas sweeping to membrane permeate side. The proposed process is rigorously modeled and optimized in a holistic manner, subject to design specifications and engineering constraints, in which the selection of the most appropriate membrane network configurations and the determination of economic operating conditions is systematically made. Technical feasibility of new membrane process is assessed in collaboration with experimental group and membrane manufacturer, while economic evaluation in conceptual costing level is carried out to obtain CAPEX and OPEX, leading to the calculation of CO₂ capture costs. The optimized sub-ambient membrane process proposed allows about 15% reduction in CO₂ capture cost and 16% in parasitic load, compared to that of the conventional multi-stage membrane process operating at ambient conditions. Case study will be given to discuss considerable advances made in the new sub-ambient membrane process and to provide conceptual insights and design guidelines in the use of membrane for CO₂ capture process in practice.

Acknowledgement

This research was supported by the Korea Carbon Capture & Sequestration R&D Center (KCRC) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, and ICT (NRF-2014M1A8A1049338)