Bubble column reactors industrial application

Sluny bubble column reactors have many applications in both industrial and environmental processes. For example, they are used in the Fischer-Tropsch synthesis in industry, or in wastewater treatment. The most important applications of these reactors are presented in Table 3.8 (Shall et al, 1982). 

Bubble column reactors (BCR) are widely used in chemical process industries to carry out gas-liquid and gas--liquid-solid reactions, the solid suspended in the liquid phase being most frequently a finely divided catalyst (slurry reactor). The main advantages of BCR are their simple construction, the absence of any moving parts, ease of maintenance, good mass transfer and excellent heat transfer properties. These favorable properties have lead to their application in various fields production of various chemical intermediates, petroleum engineering, Fischer-Tropsch synthesis, fermentations and waste water treatment. 

The list is merely suggestive. Complexity of reactive flows may greatly expand the list of issues on which further research is required. Another area which deserves mention here is modeling of inherently unsteady flows. Most flows in engineering equipment are unsteady (gas-liquid flow in a bubble column reactor, gas-solid flow in a riser reactor and so on). However, for most engineering purposes, all the details of these unsteady flows are not required to be known. Further work is necessary to evolve adequate representation of such flows within the CFD framework without resorting to full, unsteady simulations. This development is especially necessary to simulate inherently unsteady flows in large industrial reactors where full, unsteady simulations may require unaffordable resources (and therefore, may not be cost effective). Different reactor types and different classes of multiphase flows will have different research requirements based on current and future applications under consideration. 

Table 8.1 Examples of bubble column reactor applications in the chemical process industry...

Chiyoda and UOP jointly developed an improved methanol carbonyl-ation process on the basis of this supported rhodium complex catalyst the process is called the Acetica process. This process for the production of acetic acid has found several industrial applications in Asia. The process description emphasizes the use of a three-phase reactor, a bubble column, or gas-lift reactor. The reactor column contains a liquid, a solid catalyst, and a bubbling gas stream containing CO efficient dissolution of the gas in the liquid is ensured by the design, which minimizes gas-liquid mass transfer resistance. 

We focus on heterogeneous catalysis with single and multiple reactant phases, as these are the most common in practice. Examples include environmental catalysis, fat hardening, hydrodesulfurization of oil streams, hydrogenation of fine chemicals, and selective conversions catalyzed by immobilized enzymes or cells in biotechnology. The most popular reactors used in industry for multiphase applications are slurry bubble columns and trickle-bed reactors. They are shovm in Figure 1. 

In many industrial applications such as bubble columns and stirred tank reactors, it is of interest to know the local concentration of bubbles. In general, this is an extremely difficult problem because the bubbles modify the flow and one must compute shape and velocity of the bubbles simultaneously with the motion of the liquid phase. However, for dilute flows, one may be able to obtain some progress with the so-called one-way coupling approximation. In this approach, one ignores the effect of the bubbles on the motion of the liquid. This is reasonable provided that the gas volume fraction is very small and if the bubbles are smaller than the energy-containing eddies so that the turbulence created by the bubbles is unimportant. One then integrates an approximate equation of motion for the bubble. 

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