OP-II-3

PP-II-19NEW BASIC SHAPE OF CATALYSTS IN NATURAL GASREFORMING REACTORHartmann V.L. 1 , Obysov A.V. 1 , Dulnev A.V. 1 , Afanas’ev S.V. 21 LLC “NIAP-KATALIZATOR”, vhart@yandex.com2 JSC “Togliattyazot”The common present-day tendency when revamping ammonia or methanolplants is to use the existing equipment to the utmost extent. Nowadays, thebottleneck stage of such a plant is the tube furnace. The ordinary way to eliminate itis to use tubes with a greater inner diameter and an increased amount of the samecatalyst. But, with a plant upgraded from 1360 to, say, 1800 mtons per day, it is quiteexpensive concerning both tubes themselves and the catalyst volume needed.Besides, the problem arises of heat transfer through walls of wider tubes.As it was mentioned in [1], the performance of a catalyst bed in hydrocarbonsreforming is mainly proportional to catalyst bed surface area, m 2 /m 3 . To verify thisfact, some samples of both out- and up-to-date nickel-alumina natural gas (NG)reforming catalysts with more than 6% of NiO were tested using the gradient-free unitPKM-1 (Boreskov Institute of Catalysis). The discrepancy in activation energy andprefactor values lies mainly within the limits of experimental scatter.Thus a more competent solution is to increase catalyst specific bed surface area.On the other hand, according to common approach [2], pressure drop across agranular bed is expressed as:2Δ = ρ ε − 3PL 0.5f ewa ,ΔP/L – pressure drop per unit bed length, Pa/m; f e – drag (or friction) factor; ρ – gasdensity, kg/m 3 ; w – superficial linear gas flow velocity (per full bed cross-section),m/s; a – specific bed surface area, m 2 /m 3 ; ε – bed porosity, m 3 /m 3 .Thus, such a way can lead to a high pressure drop across the bed, which, in itsturn, leads to the gas compressor enormous energy consumption or even issues.It is commonly accepted that f e is a universal function of the Re number, itsvariation for granules of different types being limited to 30% [2]. So, the only way toavoid an increase in the pressure drop is to enlarge bed porosity. On this way NGreforming catalyst granules have evolved from simple cylinders (Cylinder in theTable 1) to multiperforated ones with rounded faces and even grooves.Unfortunately, granule internal porosity increase is limited by mechanical strength366