Impact of dissolved oxygen removal on solvent degradation for post-combustion CO2 capturew

•Oxidative degradation is a key operational issue in amine based CO2 capture, which can be mitigated by removing oxygen from the solvent.•Dissolved Oxygen Removal Apparatus (DORA) uses membranes to remove dissolved oxygen from capture solvents (tube side) with either a liquid scavenger or sweeping gas (shell side).•Porous membranes are effective in removing at least 90% oxygen, thereby, reducing solvent degradation. However, the performance of these membranes reduces over time due to pore wetting.•Porous membrane with a dense layer coating provide long term stability and at least 90% oxygen removal. One of the major issues encountered in the Post Combustion CO2 Capture processes is the degradation of the solvent which can be in great part attributed to the presence of oxygen in the solution. The present report focuses on the demonstration of DORA (Dissolved Oxygen Removal Apparatus), a technology developed by TNO as a counter-measure of oxidative degradation. The DORA was first operated in combination with TNO's mobile bench-scale CO2 capture pilot (5 Nm3/h flue gas capacity) with artificial flue gas, showing an instant drop of 15% and an overall reduction of approximately 70% in the ammonia emissions from the absorber, which is an indication of reduced degradation. The technology was also demonstrated using the same pilot in an industrial environment in collaboration with the facility PlantOne bringing DORA from TRL5 to TRL6. This campaign proved that DORA contributed to the deacceleration of solvent degradation. The tests were executed with a porous membrane, and it was observed that exposure to degraded solvents led to solvent leakage through this membrane. Therefore, the use of a coated membrane was proposed to optimize the operation and increase oxygen removal. The use of this membrane is demonstrated at TRL3. Along with that, a model was developed to determine mass transfer resistances and the membrane area required to remove different levels of dissolved oxygen.