(423f) CO2 Utilization for CO Production Via Fuel Cell Enabled By CO2-Selective Membrane

This presentation describes a method of CO₂ utilization for CO production via a fuel cell system that is enabled by a CO₂-selective membrane. We have synthesized a highly CO₂-selective facilitated transport membrane, showing an extraordinarily high CO₂/CO selectivity of greater than 1200 at 100 – 130°C that separates a CO₂ and CO mixture to give high-purity CO₂ on the permeate side and high-purity CO on the retentate side. The CO₂-selective membrane contained polyallylamine as the fixed-site carrier and the potassium 2-aminoisobutyrate as the mobile carrier to facilitate the CO₂ transport.

An embodiment of the CO₂ utilization is for the simultaneous production of CO and electricity using natural gas, i.e., methane (CH₄) feeding to the anode of a solid oxide fuel cell (SOFC). In this case, the CO₂ feed enters the cathode of the SOFC, where the CO₂ is converted to CO. As the conversion is not 100%, the cathode exhaust is typically a mixture of CO₂ and CO. This mixture enters a CO₂-selective membrane module, which separates the mixture to a high-purity CO product on the retentate side and a high-purity CO₂ stream on the vacuum permeate side. The methane enters the anode of the SOFC, which is oxidized into CO₂ while generating electrons to produce electricity via the external circuit (load). The CO₂ stream coming out from the anode may contain some CO due to incomplete oxidation of methane. The mixture produced at the anode may be sent to the same CO₂-selective membrane module or another one for separation. The separated CO₂ product may be combine with the CO₂ feed to go into the cathode. The methane feed may be converted to ethylene. Instead of the methane feed, the feed to the anode is paraffin, e.g., ethane or propane, for conversion to olefin, e.g., ethylene or propylene, or CO for conversion to CO₂ that is captured by the membrane.