The microscale trickle bed reactor can be used for testing commercial size catalyst, if its inherent limitations, such as channeling, wall effect, and backmixing, are overcome by diluting the catalyst bed with a nonporous inert particles of suitable size. The effect of diluent size on the performance of a microscale trickle bed reactor, catalyst bed height, as well as on operating liquid holdup at different liquid hourly space velocities, has been studied in the present investigation. The proper size of diluent, which may be used for testing as low as 5 mL of commercial catalyst in a microreactor, has been identified experimentally. The results on the hydrodesulfurization of atmospheric gas oil obtained in the microreactor, using the suitable size of diluent were compared with the data generated in a bench scale unit. The activation energy calculated from both microreactor and bench-scale reactor rate data was 21 and 25 kcal/mol, respectively.

Hydroconversion of n-heptane and toluene has been studied over a commercially proven Ni-W/SiO,-AI,O, amorphous base hydrocracking catalyst (suitable for maximizing middle distillates production from heavier feedstocks) under a wide range of operating conditions (pressure: 400-1200 psig; temperature: 315-36OoC, liquid hourly space velocity (LHSV) -1 h-' and molar hydrogen/hydrocarbon feed ratio : 6-8) to assess the hydrogenation and cracking activities of the catalyst as part of the development of a quick methodology for catalyst screening. Hydroisomerization followed by hydrocracking, and hydrogenation followed by isomerization have been found to be the major reactions with n-heptane and toluene respectively as the feeds. The hydroconversion of toluene gives a very high selectivity of hydrogenated product. With n-heptane, a very high selectivity of hydroisomerized product, together with a high ratio of hydroisomerized to hydrocracked product, is obtained.