Single Layer and Multilayers of Ru/Al2O3 Using Washcoating Method on Stainless Steel Substrate for Fischer Tropsch Synthesis in Microchannel Reactor
Major challenge of using metal based microchannel reactor is catalyst active phase deposition onto the metal surface. Washcoating method is one of the effective procedure for depositing supported catalyst onto the substrate surface. In order to control quality of the catalytic washcoated layer, stability of catalyst slurry, amount of catalyst solution and number of coatings were focused. The catalyst slurry used in this work contained 20wt% of 10%Ru/Al2O3, 5wt% of polyvinyl alcohol, 1% of acetic acid and water. The suitable pH of catalyst solution was in a range of 2–4. For the single layer coating, the good adherance of catalytic layer was observed. The highest %weight loss was 0.07% at pH value of 8. From the effect of catalyst slurry volume, 0.1 and 0.2 mL gave relatively low catlyst loading difference of before and after adhesion test. The average thickness of 0.2 mL single layer washcoating was 121.73 μm. Multilayer washcoating, the results clearly showed that the obtained washcoated layer can be used to apply onto the metallic substrate not only single layer but also multilayer. The double layer washcoating gave the highest catalyst loading per unit area for every volume of catalyst slurry. The 0.2 mL gave relatively good adherence and uniform washcoating layer in multilayer coating process. For single layer washcoat on microchannel structure, the obtained thickness was 5 μm.