MeDORA - Membrane-assisted Dissolved Oxygen Removal from Amine solution for CO2 capture
Technology
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Technology implementation
DORA is based on membrane contactor technology, where the CO2-rich solvent is contacted with the membrane interface to allow for O2 removal. DORA is placed at the bottom of the absorber and treats the CO2-rich solvent before the sump pump that circulates the amine solvents towards the stripper. DORA can also be installed after the sump pump (easier retrofitting option), but this would impact the efficiency of the technology in O2 removal and consequently the cost reduction potential in terms of solvent management.
The membrane contactor operates in liquid-gas mode, with the liquid solvent running on the shell side of hollow fiber membranes. A sweeping gas (N2) combined with vacuum is used on the lumen side of the membrane. Because of the operation mode, any physically dissolved gas will be removed from liquid solvent. In addition, the DORA concept is designed to be solvent-independent.
The footprint of the technology is expected to be very small compared to the rest of the capture plant. In the figure below, a picture of the skid installed at the HVC facility is shown, treating the whole solvent stream of the pilot plant (about 13 m3/h).
Technology impact
DORA technology is expected to impact the operation of amine-based capture plants at 2 different levels: offering an efficient solvent management solution while implementing an effective CO2 conditioning strategy.
- By removing at least 90% of the dissolved O2 in rich amine solvents, DORA will deliver:
- Reduction of solvent degradation and hence reduction of solvent management cost up to 80% for MEA (1.93 → 0.39 €/tCO2) and 57% for CESAR1 (4.97 → 2.13 €/tCO2)
- Cost efficiency, with CAPEX and OPEX that add up to ca. 0.30 €/tCO2
- Reduction of the frequency of solvent reclaiming (hazardous operation), increasing the safety of CO2 capture plants
- Reduction amine losses (i.e., volatile emissions) and the volume of waste streams, greatly reducing the environmental footprint of amine-based CO2 capture plants
- Due to the technology working principle, DORA will also deliver:
- Similar removal rates of all other physically dissolved gases (e.g., SOx, NOx, N2, Ar, CO), together with O2 improving the quality of the CO2 product
- Reduction in off-gas production from liquefaction processes (from 5 vol% to ≤ 1 vol%), significantly limiting CO2 losses as well as reducing the power consumption per ton of liquefied CO2.