Carbon treating at the National Carbon Capture Center for the mitigation of PZ oxidation

Abstract

In previous work, carbon treating appeared to mitigate piperazine (PZ) oxidation at the bench and pilot scale. However, the long-term effects of carbon treating and its ability to mitigate Fe-catalyzed oxidation at the pilot scale are still not understood. The PZAS (Piperazine with Advanced Stripper) process was tested in the pilot plant at the National Carbon Capture Center from December 2022 to October 2023. Carbon treating was tested for a total of 4633 h and was effective at lowering Fe solubility, reducing NH3 production, and mitigating the accumulation of UV absorbing species. However, once the carbon is saturated, it appears to act as a catalyst bed for oxidation and corrosion. Operational recommendations include using online NH3 monitoring or on-site UV-Vis spectroscopy to determine when to exchange the carbon. The waste carbon will likely be classified as hazardous waste due to high Cr.

Keywords: amine scrubbing, carbon treating, reclaiming, amine oxidation