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Wall effect of a packed bed with pellet particles

In this study, effects of voidage distribution to gas velocity profile in a packed bed with pellet particles was empirically investigated. Uniformity of local velocity at the top of the bed was clearly observed with decreasing of bed height and flow rate. For 400 mm of bed height, the measured velocities are a well fitting to Fahien and Stankovich model for any expected flow rate. | Vietnam Journal of Science and Technology 56 (2A) (2018) 31-36 WALL EFFECT OF A PACKED BED WITH PELLET PARTICLES Tran Duy Hai*, Phan Đinh Tuan Ho Chi Minh City University of Natural Resources and Environment, 236 Le Van Sy Street, Tan Binh District, Ho Chi Minh City * Email: tdhai@hcmunre.edu.vn Received: 15 March 2018, Accepted for publication: 14 May 2018 ABSTRACT Fluid flow profile is a dominate role in the performance of packed bed reactor. In small ratio of column-to-particle diameter, velocity pattern is strongly affected by voidage distribution, which depends on radial coordinate, flow rate and bed height. In this study, effects of voidage distribution to gas velocity profile in a packed bed with pellet particles was empirically investigated. Uniformity of local velocity at the top of the bed was clearly observed with decreasing of bed height and flow rate. For 400 mm of bed height, the measured velocities are a well fitting to Fahien and Stankovich model for any expected flow rate. Keywords: chlorination, titanium tetrachloride, wall effect, flow distribution, packed bed. 1. INTRODUCTION In titanium metallurgical process, titania ores are firstly chlorinated to produce titania tetrachloride [1]. In presence of carbon as reducing agents, titania reacted with chlorine gas at high temperature and this reaction can be performed in a fixed bed reactor. In order to improve contact of titania and carbon powder, these materials must be well mixed with a binder; and then pressed to form pellets [2]. The chlorination occurs in pellets surface. Therefore, flow distribution of chlorine gas in bed is one of important properties that affect to efficiency of titania chlorination. Fixed beds have been applied in various processes such as distillation, gas-liquid absorption, fluid-solid chemical reaction, etc. Voidage is a significant parameter to describe the fluid flow and heat transfer in a bed [3-4]. However, the radial distribution of bed porosity varies from center