Desorption kinetics of thick zeolite coatings prepared by induction heating for adsorption heat pump applications

• Published in: Journal of porous materials Vol. 29; no. 4; pp. 1225 - 1238
• Main Authors: Maraş, Taylan, Tatlier, Melkon, Erdem, Ayşe
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-08-2022; Springer Nature B.V
• Subjects: Addition polymerization; Adsorption; Catalysis; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Coatings; Crystallization; Cylinders; Desorption; Electric double layer; Gravimetric analysis; Heat pumps; Induction heating; Kinetics; Mass transfer; Metal surfaces; Pellets; Physical Chemistry; Stainless steels; Substrates; Thickness; Tubes; Wire cloth; Zeolites; Wire meshes; Zeolite; Coating; Kinetics; Induction heating
• ISSN: 1380-2224; 1573-4854
• DOI: 10.1007/s10934-022-01248-8

Zeolite coatings were directly crystallized on stainless steel substrates, which included double layer wire mesh cylinders and tubes, by induction heating. X-ray diffraction (XRD), thermal gravimetry (TG) and scanning electron microscopy (SEM) analyses were performed to characterize the materials obtained. Thermal and ultrasonic treatments were performed to assess the mechanical stabilities of the coatings. The desorption kinetics of the coatings were also investigated and compared to those obtained for zeolite NaX in various pellet and powder forms. Coatings of up to about 1.2 mm mass equivalent thickness, consisting mainly of NaX, could be prepared on various substrates using new clear solution compositions. The coatings grown on double layer wire mesh cylinders as well as double layer meshes welded to tubes were observed to be highly stable, especially when covered by an additional polymer layer. Utilizing the zeolite as a coating on metal surfaces, instead of in pellet or powder form, improved heat transfer properties significantly, mainly due to the firm contact between the metal and zeolite provided by direct crystallization. Consequently, the desorption kinetics of the zeolite NaX coatings were also much superior to the other forms of zeolite NaX investigated in this study. This may be very beneficial for various applications, such as for use in adsorption heat pumps. The coating thickness affected the heat and especially mass transfer properties of the zeolite.