III International Conference

PP-III-69In order to get data on gas-dynamic drag involving only catalyst bed itself, pressure dropsvs. flow rates were measured for the granular beds in the steel tube 95 mm in inner diameterand 1.635 m long with the air flow at ambient temperature in it. Flow rates were chosen insuch a way that Re number and ρw 2 complex values would be in the same range as in the tubefurnace of typical Kellogg ammonia plant. Granules were of various dimensions and shapes,namely, rings, perforated cylinders and spheres. Results are shown in the fig. 1.Blue diamonds there show values, calculated from experimental data, and solid lines –their fitting using power law. It can be seen that data for rings (K15&K10) differ distinctlyfrom those for perforated cylinders (KB31, KB51, N22) and spheres (Sp19), as well as powerlaw parameters fitting them (exponent values are 0.22 and 0.28, respectively. The differencebetween rings may be due to effect of their dimensions (outer diameters are 15 mm for K15and 10 mm for K10) on the bed structure. The same can be saidabout KB31 and KB51 (outer diameters are 19 mm and 16 mm,respectively). KB31 has slightly bigger central hole than N22(shown on fig. 2), but that is enough for the latter to demonstratethe best gas-dynamic properties. Having the sufficient value of a(427 m 2 /m 3 ) it is now widely used commercially mainly in Russianammonia plants.Fig. 2. N22 granulesPower law parameters fitting these data differ essentially from commonly acceptedones[1]. Drag factor values for N22 are surprisingly low. On the whole, the discrepancies ingas-dynamic properties in question are greater than one can expect.References1. Aerov M.E., Narinskiy D.A., Todes O.M. Apparatuses with static granular bed//Khimiya –Leningrad, 1979.2. Temkin M.I. Advances in Catalysis, v.28, p.173598