Catalytic Reduction of Residual Oxygen for the Purification of Carbon Dioxide Streams from Pressurized Oxy-Combustors

Research output: Contribution to conferencePaperpeer-review

Abstract

Pressurized oxy-combustion (OC) is regarded as an energy-efficient alternative to atmospheric OC. To utilize the captured carbon dioxide (CO2) from pressurized OC for enhanced oil recovery or carbon storage in geological formations, the CO2 product stream must meet the required purity specifications. One major impurity in OC flue gases is residual O2 (e.g., 3 vol%). In this study, a catalytic approach has been investigated to remove the residual O2 through a reduction reaction with injected methane (CH4) in a reverse-flow fixed-bed (RFFB) reactor. The performance was tested for a supported copper (Cu)-based catalyst synthesized by incipient wetness impregnation and a cobalt-manganese (CoMn) oxide catalyst synthesized by a coprecipitation method. A commercial Cu-based catalyst was also studied as the reference. Experimental results revealed that under the reverse-flow operation, the temperature profiles in the reactor were symmetrical on both sides of the catalyst zone and were more homogenous than those under the conventional one-direction-flow operation. Among the tested catalysts, the CoMn catalyst was the most reactive for promoting the reduction of O2 with CH4, able to attain >95% O2 removal at 475 °C and a gas hourly space velocity (GHSV) of 18,000 h-1 with a feed gas containing 3 vol% O2. Under all experiments, the concentrations of carbon monoxide (CO) were lower than 30 ppmv in the effluent gas streams. The reaction between O2 and CH4 could be depicted by using the Mars-van Krevelen redox mechanism based on a two-step reduction-oxidation reaction pathway.

Original languageEnglish (US)
StatePublished - 2021
Event15th Greenhouse Gas Control Technologies Conference, GHGT 2021 - Virtual, Online, United Arab Emirates
Duration: Mar 15 2021Mar 18 2021

Conference

Conference15th Greenhouse Gas Control Technologies Conference, GHGT 2021
Country/TerritoryUnited Arab Emirates
CityVirtual, Online
Period3/15/213/18/21

Keywords

  • O2 impurity
  • Oxy-combustion
  • catalyst
  • high pressure
  • reverse-flow fixed-bed reactor

ASJC Scopus subject areas

  • General Energy
  • Industrial and Manufacturing Engineering
  • Management, Monitoring, Policy and Law
  • Pollution

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