Steel fiber-zeolite composite laminates for carbon capture via induction swing adsorption

Induction heating offers the possibility to electrify and intensify temperature swing adsorption processes. Typically, ferromagnetic powders are used as susceptor materials in composite adsorbents for induction swing adsorption (ISA). In this work, stainless steel fibers are used as an alternative susceptor material and were incorporated into structured zeolite laminates. The high specific absorption rates (SAR) of the steel fibers, even at low coil currents, demonstrate they are excellent susceptor materials for ISA, whilst laminates have been shown to yield good mass transfer kinetics and low flow resistance. A column with eight narrowly spaced (0.4 mm) steel fiber-zeolite composite laminates (1.0 mm thick) was assembled. Temperature measurements show the laminate adsorber heats up rapidly when subjected to an alternating electromagnetic field, with heating rates up to 3.5 °C/s at a current of 71.4 A. The composite laminates were tested for the separation of a 15:85 mol% CO₂/N₂ mixture, in the context of post-combustion carbon capture. Average and maximum desorption rates up to 44.3 mg/(g·min) and 110.9 mg/(g·min) were achieved, respectively. These very high desorption rates, compared to average desorption rates below 25 mg/(g·min) reported for other materials at similar experimental conditions, are the result of the large CO₂ adsorption capacity of the laminates and efficient eddy current heating of the embedded steel fibers. Steel fiber-zeolite composite laminates combine the benefits of structured adsorbents with the advantage of rapid electrified heating.