(567d) Inductive Heating As Regeneration Method in TSA for CO2 Capture

Classical large-scale TSA has important drawbacks for large scale CO2 capture processes, such as a low heating rate due to purge gas temperature and pressure drop limits, and are energy inefficient as typically >50% of the energy input is wasted as sensible heat at the outlet of purge stream line. Besides, the adsorbate needs to be separated from the carrier gas downstream. Contrary to TSA, pressure swing processes can operate very fast but require more valuable, high quality electrical energy input and, depending on how strongly CO2 is adsorbed to the surface, may require very low pressures to regenerate. These low pressures (often less than 10 kPa) lead to large piping and valve sizes to minimize pressure drop and therefore restrict the scalability of the technology.

To overcome the difficulties of TSA processes, different approaches were chosen. One approach is to heat the adsorbent indirectly via a heat exchanger 1,2. The benefit of this approach is the heating of the whole adsorbent bed at the same time without the need to a heating gas stream, and the drawback is an extra thermal energy need due to heat capacity of the heat exchanger and more CAPEX due to internal heat exchanger. The other approach is to use electricity to heat the adsorbent inside the bed via resistive heating of the adsorbent (ESA) 3-5. This concept fits very well with electrification strategies, yet does require a continuous conductive path in the adsorption bed. The third approach is the contactless heating of the adsorbent inside the bed via microwave or induction 6,7. In this approach, there is no need to the continuity of the adsorbent along the bed, nonetheless, the technology is in its early stages for such process.

In this work, we have studied inductive heating as a regeneration method in CO₂ capture. A hybrid ferromagnetic adsorbent was developed, that can be heated rapidly using an inductive heating coil. The inductive heating efficiency was determined as a function of applied power. Separation of CO₂ from synthetic flue gas mixtures was studied using a packed bed of the hybrid adsorbent. Cyclic adsorption-desorption experiments were carried out, in which the adsorbent was regenerated using inductive heating. It was demonstrated that the adsorbent bed can be heated to temperatures above 120°C in less than one minute.

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