Membrane Contactors for Post-Combustion CO2 Capture: Progress towards pilot plant operation
Sustainable process-product development & green chemistry
Sustainable & Clean Technologies - III: Combustion & Emission (T1-6)
Keywords: CO2 capture, post-combustion, solvents, absorption, membrane contactors
It is becoming clear that to halt the change in the global climate, CO2 emissions need to be reduced by more than 80% in the middle of this century. Capture and storage of CO2 (CCS) is a technology which enables large reductions of CO2-emissions from fossil fuel fired power plants. As part of a balanced technology portfolio for emission reductions, it is at present receiving considerable attention, because other methods to reduce CO2-emissions (e.g. renewable energy) will take considerable time before they can impact on the required large scale. CCS is also attractive because it can be implemented directly in current power plants, by using post-combustion capture of CO2. The leading technology for post-combustion capture is a chemical solvent which reacts reversibly with CO2. Increasing the solvent temperature will lead to the release of CO2. The process is, however, rather expensive not in the last because of the high costs of absorbers.
Membrane contactors represent a novel way to contact gas and liquid streams, which can reduce costs due to the fact the equipment is rather compact. Its advantages lie in the fact the equipment can be made more compact and with a smaller footprint. This presents advantages in terms of investment cost reduction.
TNO has been developing this process successfully for a number of small-scale applications. The technology is based on combinations of dedicated solvents with cheap polypropylene membranes. The presentation will focus on the following items:
1. Principles and benefits of membrane contactors
Membrane contactors will enable the establishment of a compact apparatus for gas separation based on absorption processes.
2. Selection and characterisation of membranes for membrane contactors
Membranes should fulfil requirements regarding their porosity, thickness, pore size, permeability to be useful for contacting applications.
3. Development of dedicated solvents for CO2-capture
One of the most critical development items is the system stability, i.e. whether the gas-liquid interface can be fixed at the membrane surface for a sufficiently long period without wetting the membrane pores.
4. Development of dedicated membrane modules for use as contactors
Membrane modules should exhibit good fluid distribution and low gas-side pressure drop and this leads to module concepts based on transversal flow.
5. Performances of membrane contactors in laboratory conditions
Results from laboratory set-ups will be presented for a variety of conditions.
6. Pilot plant operation with power plant flue gases
The application of membrane for reduction of CO2-emissions from power stations will be presented. TNO is building a pilot plant at a coal fired power station, which will be the largest pilot plant for testing membrane contactors for gas absorption.
Presented Tuesday 18, 12:00 to 12:20, in session Sustainable & Clean Technologies - III: Combustion & Emission (T1-6).
