Experimental Studies On Hydrodynamics In Slurry Bubble Columns

Fischer-Tropsch synthesis is the most important part of the indirectly coal liquation process. It is a way to converse the synthesis gas into hydrocarbon products. Slurry bubble column reactors are considered as the most ideal commercial scale reactors for Fischer-Tropsch synthesis, because of its own strong points such as simple structure, low construction and operating cost, good heat transfer property.In this paper we simulate the real construction of the slurry bubble column and reaction system for Fischer-Tropsch synthesis. We measure the hydrodynamic parameters in the bubble columns, and compare them with the results of the gas-water system bubble column without internals. The reaction system in the slurry bubble column for Fischer-Tropsch synthesis is a three-phase reaction system. Tubular heat exchanger is used to remove the heat generated by the reaction in the slurry bubble column. In order to approach the real flow in the commercial scale slurry bubble column, we use air-water-air core glass bead to simulate the three phase of the Fischer-Tropsch synthesis, and we use some tubes as internals in the bubble column to simulate the tubular heat exchanger. We get some information of the flow in the bubble column through measuring of the hydrodynamic parameters like gas hold up and axial liquid velocity.In this paper, we study the impact of the superficial gas velocity, tower diameter and solid concentration on the hydrodynamics in bubble columns. We analysis the distribution of gas hold up (electrical conductivity probe) and axial liquid velocity (Pavlov tube) in bubble columns with large diameter (~760mm) under the operation conditions of high superficial gas velocity (~0.93m/s), high solid concentration (~30vol%).The gas holdup in the bubble column appears as parabolic distribution. The liquid flows upward in the center and downward near the wall, which appears as a loop in the bubble column. And superfacial gas velocity, tower diameter and solid concentration have apparent effect on the distribution of gas holdupand axial liquid velocity. The present of uniformly distributed.tubes makes steeper distribution of both gas holdup and axial liquid velocity.