OP-II-3

OP-I-22calculated values of pressure drop amounts to 6.2% being much less than for allknown correlations.In case of multihole particles there are more geometric parameters, thus theproblem being fundamentally more complicated. Experiments with pressure dropmeasurements were carried out in a vertical tube with ID of 84 mm with particlesshaped as shown on a figure. Gas velocity was varied from 0.2 to 3.0 m/sec. Ratio oftube diameter to maximum dimension of particles amounted 3.8-8.4.In the same manner as for Raschig rings, a two-level model was considered formultihole particles. A gas stream flowing through all holes meets additionalresistance being a baffle between holes. On the other hand, a circumfluent flowaround particles does not interact with surface of these baffles. Taking into accountthese factors, by averaging equations of energy and mass conservation laws andassuming uniform distribution of rings in an orientation angle, a closed system ofthree simple equations is obtained. This system allows calculating pressure drop in abed and averaged velocities of flows inside and about particles. The equationsinclude as coefficients geometric parameters of particles, parameters of the Ergunequation for bulk particles (including effect of container walls according to [6]) and theobtained for Raschig rings averaged channel flow resistance coefficient. Thus, thesystem does not contain any additional empiric coefficient. It should be noticed thatErgun equation coefficients for bulk trilobes differ from that for cylinders.A mean-squared deviation of experimental and calculated values of pressuredrop amounts to 7-9% for all multihole particles under consideration. Thus, thedeveloped method of pressure drop calculation gives estimations being in goodagreement with experimental data obtained.References[1]. Brauer H., Druckverlust in Fullkorpersaulen bei Einphasenstromung, Chem.-Ing.-Techn. (1957),29 (12) 785-790.[2]. Zhavoronkov N.M., Hydrodynamic basis of scrubber processes and heat transfer in scrubbers.Moscow, Sovetskaya nauka, (1944), in Russian.[3]. Smirnov E., Kuzmin V., Zolotarskii I., Radial Thermal Conductivity in Cylindrical Beds Packed byShaped Particles, Chemical Engineering Reserch and Design, (2004), 82(A2): 293-296.[4]. Nemec D., Levec J., Flow through packed bed reactors: 1. Single-phase flow, ChemicalEngineering Science (2005) 60, 6947-6957.[5]. Ergun S. Fluid flow through packed columns. Chemical Engineering Progress, (1952), 48, 89-94.[6]. Eisfeld B., Schnitzlein K., The influence of confining walls on the pressure drop in packed beds,Chemical Engineering Science (2001), 56, 4321-4329.79