Induction heating, a smart method of sorbent heating in thermal swing carbon capture process

Electrification of chemical processes is one of the approaches to mitigate global warming. Regarding the fact that in chemical engineering, it is fuel-based thermal energy that drives many processes, replacing such heating methods with the most advanced electrified method will be a great step toward carbon neutrality. In the present study, the application of induction heating for adsorbent heating in a TSA process has been investigated. For such a purpose, extrudates of composite sorbent containing 13X zeolite and Fe3O4 were prepared and subjected to heating quantification, equilibrium measurement, and dynamic ad/desorption experiments. The equilibrium measurement proved that the equilibrium capacity of the composite sorbent is an arithmetic average of the susceptor-free sorbent and the iron oxide powder. By comparing the measured desorption rates with reported data in the literature, it was found that at high coil currents, the desorption rate is one order higher than reported values.

Introduction
Thanks to the high separation factor, separation by adsorption is considered to be less energy-intensive than more mature technologies such as distillation [1]. This high separation factor comes from solid adsorbents that have a very high surface area and unique porosity which is tuneable for many specific separations. With this characteristic, adsorption has a great chance to replace some of the existing separation technologies as it did before with the absorption dehydration unit [2]. With this potential and the fact that chemical industries are going to become electrified [3], the electrification of adsorption technology is inevitable. The aim of this study is to use commercially available adsorbents and susceptors as they are for shaping composite sorbent and testing the renderability of them under induction, and to shed light on different aspects of the induction heating in adsorbent regeneration.

Experimental
The composite sorbent was prepared by mixing 13X zeolite powder (UOP, sorbent), bentonite (Sigma Aldrich, binder), Fe3O4 (Inoxia, susceptor), and methylcellulose (Sigma Aldrich, plasticizer) (Figure 1). Then the obtained paste was extruded into 1 mm noodles and after drying overnight in ambient atmosphere crushed into short pieces (~ 3mm). The obtained extrudates were calcined at 700 °C for two hours, and directly transferred to a sealed container for further use.

Results
The evaluated desorption dynamics confirmed that at a high energy absorption rate, the regeneration time can be in the order of one minute, which is at least one order lower than the regeneration time of a normal TSA process (Table 1). Such a short regeneration time will effectively reduce the amount of adsorbent inventory.