Chemical industry multi-phase reactors

These phenomena may be important for a restricted number of chemical reactor systems, as for example certain industrial multi-phase systems operated in bubble column and fluidized bed reactors. 

Harmsen G.J. and Chewter L.A. (1999). Industrial applications of multi-functional, multi-phase reactors. Chemical Engineering Science 54, 1541-1545. 1.3.1... 

In a multi-phase catalytic reactor, the reacting species are dissolved in two different fluid phases (e.g., in a gas-liquid system or in liquid-liquid system) which are separated by a phase interface, and the catalyst is located in one of the fluid phases or in a dissolved form (as for example an homogeneous catalyst) or as a third heterogeneous phase (e.g., a solid phase). When a gas-liquid system is in the presence of a solid phase catalyst, the reactor is referred to as a three-phase reactor. Multi-phase reactors represent one of the most important classes of chemical reactors and they are widely used in many industrial sectors, as for example chemical, petrochemical, biotechnological, pharmaceutical and food processing industries (Barnett, 2006 Biardi and Baldi, 1999 Henkel, 2000 Nauman, 2008). Multi-phase reactors have typical industrial application in ... 

Gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are widely used in the chemical and petrochemical industries for processes such as methanol synthesis, coal liquefaction, Fischer-Tropsch synthesis and separation methods such as solvent extraction and particle/gas flotation. The hydrodynamic behavior of gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are of great importance for the design and scale-up of reactors. Although the hydrodynamics of the bubble and slurry bubble columns has been a subject of intensive research through experiments and computations, the flow structure quantification of complex multi-phase flows are still not well understood, especially in the three-dimensional region. In bubble and slurry bubble columns, the presence of gas bubbles plays an important role to induce appreciable liquid/solids mixing as well as mass transfer. The flows within these systems are divided into two... 

The first industrial plant using n-butane to manufacture maleic anhydride was started up by Monsanto in 1984. At the time, 20 per cent of the maleic anhydride production capacity of this company switched from benzene to butane. Since then, three other manufacturers in the United States (Amoco, Ashland and Denka Chemical), and two in Western Europe (Bayer and Huh) have followed a similar procedure, so that ail maleic anhydride produced today in the United States is based on butane feedstock and nearly 50 per cent of worldwide installed capacity operates by this method. The n-butane is oxidized in the vapor phase, in a multi-tube reactor, on a fixed bed of catalyst based on phosphorus, vanadium and iron, deposited on a silica/alumina support... 

For a chemical reaction to be carried out on an industrial scale, conditions for high reaction rates are usually preferred. In the case of two- or multi-phase processes we often encounter the situation b described above. This means that we have to look at the reactor primarily as a contacting device. The reactor configuration, by which we bring the phases together, will then have a significant influence on both the reaction rate and on the selectivity. 

From diese various estimates, die total batch cycle time t(, is used in batch reactor design to determine die productivity of die reactor. Batch reactors are used in operations dial are small and when multiproducts are required. Pilot plant trials for sales samples in a new market development are carried out in batch reactors. Use of batch reactors can be seen in pharmaceutical, fine chemicals, biochemical, and dye industries. This is because multi-product, changeable demand often requues a single unit to be used in various production campaigns. However, batch reactors are seldom employed on an industrial scale for gas phase reactions. This is due to die limited quantity produced, aldiough batch reactors can be readily employed for kinetic studies of gas phase reactions. Figure 5-4 illustrates die performance equations for batch reactors. 

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