Preparation and Performances of Hierarchical Structured HZSM‐5 Washcoating on Stainless‐Steel Substrates

Abstract

The washcoats of the hierarchical HZSM‐5 zeolite (through desilication) were prepared on the inner surface of SS304 stainless‐steel tubes. The properties of slurries and coatings were characterized by analysis of particle size, measurements of rheological property, loading, adhesion, and finally the catalytic cracking test. It was found that introducing mesoporosity on the zeolite crystals was beneficial for reducing the particle size during ball milling for slurries preparation, which was helpful for improving loading due to a significant change in the rheological property. As the interaction between the particles with different sizes was enhanced after ball milling, the adhesion of the prepared coatings was improved. The catalytic activity and stability of the hierarchical HZSM‐5 coatings for the catalytic cracking of n‐dodecane were 56% and 75% higher than that of the conventional one, respectively. This probably resulted from the enhanced diffusion rate of reactant and products in the crystals and the coatings.

Efficient Coke Inhibition in Supercritical Thermal Cracking of Hydrocarbon Fuels by a Little Ethanol over a Bifunctional Coating

“…This process was repeated three times, and finally the weight loss of the tube was measured. 23 2.4. Thermal Cracking Operation Apparatus and Analysis Procedure.…”

“…3 mm × 0.5 mm × 1000 mm) by the wash-coating method. Details of the coating procedure were described in previous work . The average loading weight of the coating is 1.0 ± 0.1 mg/cm 2 (three counts).…”

“…The thermal shock test was performed by heating the coated tubes to 800 °C in 1 min (DC electric heated), holding at that temperature for 2 min, and then immediately cooling down to room temperature. This process was repeated three times, and finally the weight loss of the tube was measured …”

“…This phenomenon was widely observed in other works. 15,23,40,41 In contrast, the bifunctional coating remained tight and smooth after burning. It can be inferred that the bifunctional coating has good stability at high temperatures (Figure 9b).…”

Influence of alumina binders on adhesion and cohesion during preparation of Cu‐SAPO‐34/monolith catalysts

“…Co‐extrusion of the catalyst and cordierite feedstock is an established method for preparing monolithic catalysts which more active sites are internal to the support, resulting in the fact that more catalysts were used during preparation . Methods of coating the catalyst supports with additional support material, including hydrothermal synthesis, sol‐gel processing, chemical vapor deposition and washcoating . Washcoating is an efficient viable method to prepare a monolithic catalyst with an even distribution of active phase.…”