Gases continued reaction, homogeneous

Continuous-flow Reactors for Gas-Liquid Reactions (Homogeneous Catalysis)... 

Homogeneous reactions are those in which the reactants, products, and any catalysts used form one continuous phase (gaseous or liquid). Homogeneous gas phase reactors are almost always operated continuously, whereas liquid phase reactors may be batch or continuous. Tubular (pipeline) reactors arc normally used for homogeneous gas phase reactions (e.g., in the thermal cracking of petroleum of dichloroethane lo vinyl chloride). Both tubular and stirred tank reactors are used for homogeneous liquid phase reactions. 

C. The period 1985-2006. While much of the groundbreaking research on homogeneous water-gas shift was brought to light between about 1977 and 1984, as summarized by the review of Laine and Wilson,77 the homogeneously catalyzed water-gas shift reaction has continued to be an active field of research. Following the initial pioneering work, a brief overview of the period 1985-2006 is provided. 

Chapter 1 reviews the concepts necessary for treating the problems associated with the design of industrial reactions. These include the essentials of kinetics, thermodynamics, and basic mass, heat and momentum transfer. Ideal reactor types are treated in Chapter 2 and the most important of these are the batch reactor, the tubular reactor and the continuous stirred tank. Reactor stability is considered. Chapter 3 describes the effect of complex homogeneous kinetics on reactor performance. The special case of gas—solid reactions is discussed in Chapter 4 and Chapter 5 deals with other heterogeneous systems namely those involving gas—liquid, liquid—solid and liquid—liquid interfaces. Finally, Chapter 6 considers how real reactors may differ from the ideal reactors considered in earlier chapters. 

The reactor is operating in liquid phase at bubble point conditions. Fresh and recycled ethylene are fed to the liquid phase of the reactor through a gas distributor. The homogeneous catalyst is continuously fed to the reactor section. The dimerization reaction is carried out at about (50-600°C and 20-30 atm.)[14] with a reaction time of about (4-6) hrs. The homogeneous catalytic reaction proceeds at an ethylene conversion of about 80-85 percent per pass with a selectivity to butene-1 approaching 93%. The exothermic heat of reaction is removed by means of external pump-around loop equipped with a cooler. The reactor effluent is withdrawn from the reactor as a liquid containing the catalyst. 

When using conventional homogeneous Lewis or Br0nsted acidic catalysts only liquid-phase reactions are applicable. With heterogeneous catalysts gas-phase reactions, which are readily performed continuously, can also be realized. The product is readily separated from the catalyst and higher efficiency is usually achieved (space-time yield). The rearrangement of styrene oxides in the gas phase described later in this section [8,15,16] is an example of the improvement of yields by changing the reactor concept from liquid- to gas-phase. 

Gas-liquid reactions are one of the areas where the use of equations of state is particularly attractive. In these reacting systems equations of state can handle subcritical and supercritical components under a wide range of conditions. Multiphase and supercritical conditions can be described with a proper equation of state, going from the heterogeneous to the critical and homogeneous regions in a continuous way. Baiker et have stressed the importance of... 

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