Selective-exhaust gas recirculation for CO2 capture using membrane technology

Membranes can potentially offer low-cost CO2 capture from post-combustion flue gas. However, the low partial pressure of CO2 in flue gases can inhibit their effectiveness unless methods are employed to increase their partial pressure. Selective-Exhaust Gas Recirculation (S-EGR) has recently received considerable attention. In this study, the performance of a dense polydimethylsiloxane (PDMS) membrane for the separation of CO2/N2 binary model mixtures for S-EGR application was investigated using a bench-scale experimental rig. Measurements at different pressures, at different feeding concentrations and with nitrogen as sweep gas revealed an average carbon dioxide permeability of 2943 ± 4.1%RSD Barrer. The bench-scale membrane module showed high potential to separate binary mixtures of N2 and CO2 containing 5–20% CO2. The permeability was slightly affected by feed pressures ranging from 1 to 2.4 bar. Furthermore, the separation selectivity for a CO2/N2 mixture of 10%/90% (by volume) reached a maximum of 10.55 at 1.8 bar. Based on the results from the bench-scale experiments, a pilot-scale PDMS membrane module was tested for the first time using a real flue gas mixture taken from the combustion of natural gas. Results from the pilot-scale experiments confirmed the potential of the PDMS membrane system to be used in an S-EGR configuration for capture of CO2

Design, Process Simulation and Construction of a 100 kW Pilot-scale CO2 Membrane Rig: Improving in situ CO2 Capture Using Selective Exhaust Gas Recirculation (S-EGR)

Carbon capture and storage (CCS) from natural gas fired systems is an emerging field and many of the concepts and underlying scientific principles are still being developed. Cranfield University has worked as part of a consortium on a UK-funded project called Gas-FACTS to enhance the CO2 capture performance from natural gas-fired power plants using exhaust gas recirculation (EGR) and selective EGR (S-EGR) technologies. Preliminary studies suggest this approach can boost the CO2 content in the feed gas up to 3 times compared to the ‘no recycle’ case (CO2 concentration increased to 18% vs. 6%), with a consequent reduction in flow to the post-combustion capture unit by a factor of three compared to conventional, non S-EGR. For this project, Cranfield developed a pilot-scale 100 kW CO2 membrane rig facility in order to investigate simultaneously EGR and S-EGR technologies, the latter being achieved by using a CO2 sweep air polymeric membrane. A bench-scale membrane rig has also been developed to investigate the permeability and selectivity of different polymeric membranes to CO2. Currently a small-scale polydimethylsiloxane (PDMS) membrane module is also being investigated to study its selectivity/permeability. The tests include exploring the performance improvement of the PDMS membrane using different operating conditions with a view to developing scale-up procedures for the membrane unit for the actual 100 kW pilot-scale rig. Process simulations were performed using Aspen Plus software to predict behaviour of the pilot-scale rig using a model developed based on empirical parameters (i.e., mass transfer coefficient of CO2 through the membrane and permeance), measured in the bench-scale membrane test unit. The results show that CO2 concentrations of up to 14.9% (comparable to CO2 level in coal combustion) can be achieved with 60% EGR, with a 90% CO2 removal efficiency of the membrane units. However, the results generated with the membrane model in which specific permeance values to PDMS were applied, predicted concentrations of CO2 in flue gases up to 9.8% (v/v) for a selective recycle of 60%. The study shows that the S-EGR technique is an effective method that can provide similar conditions to that of a coal-fired power plant for the post-combustion capture system operating on natural gasfired units, but also highlights the fact that more research is required to find more suitable materials for membranes that optimise the CO2 removal efficiencies from the flue gas. Keywords: Carbon dioxide capture; Gas-CCS; Exhaust gas recirculation (EGR); CO2 selective membrane, Selective EGR (S-EGR

Selective-exhaust gas recirculation for CO2 capture using membrane technology

Membranes can potentially offer low-cost CO2 capture from post-combustion flue gas. However, the low partial pressure of CO2 in flue gases can inhibit their effectiveness unless methods are employed to increase their partial pressure. Selective-Exhaust Gas Recirculation (S-EGR) has recently received considerable attention. In this study, the performance of a dense polydimethylsiloxane (PDMS) membrane for the separation of CO2/N2 binary model mixtures for S-EGR application was investigated using a bench-scale experimental rig. Measurements at different pressures, at different feeding concentrations and with nitrogen as sweep gas revealed an average carbon dioxide permeability of 2943 ± 4.1%RSD Barrer. The bench-scale membrane module showed high potential to separate binary mixtures of N2 and CO2 containing 5 to 20% CO2. The permeability was slightly affected by feed pressures ranging from 1 to 2.4 bar. Furthermore, the separation selectivity for a CO2/N2 mixture of 10%/90% (by volume) reached a maximum of 10.55 at 1.8 bar. Based on the results from the bench-scale experiments, a pilot-scale PDMS membrane module was tested for the first time using a real flue gas mixture taken from the combustion of natural gas. Results from the pilot-scale experiments confirmed the potential of the PDMS membrane system to be used in an S-EGR configuration for capture of CO2

European Journalism Observatory- a platform for training and professional networks in the Faculty of Information Sciences

The launching of a Spanish platform within the Observatory will serve as a training laboratory for undergraduate and graduate students of the Faculty of Information Sciences at the same time as for establishing a professional media network in and outside Spain. The European Journalism Observatory (EJO) is a network of 14 non-profit media research institutes in 11 countries where Spain continue to be the missing element. All researchers in the EJO network actively strive to transfer their knowledge to the media industry as well as interested publics outside the scientific community, as a platform to enable online availability of at least a portion of many publications in several languages