Reactive or Catalytic Distillation

Reactive or catalytic distillation has emerged as a significant development in recent years, the original patents were obtained by L.A. Smith in the early 1980s. Several research groups have considered a range of specific systems and applications and a substantial body of literature has been published. The main system that has been investigated and reported is the production of methyl tert-butyl ether (MTBE) mainly due to the high efficiency of the process, and also the related systems of ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME). The technique includes reactive (homogeneous catalyst) or catalytic effects (heterogeneous catalyst acts as the packing) within the traditional distillation equipment. The design requires a combination of the well-known mass and energy balance equations with the individual reaction mechanisms, and consideration of heats of reactions. The design of such systems requires modelling of the mass transfer, reaction and separation, thermal effects, and the inherent control systems. An additional requirement is the knowledge of any possible side reactions and by-product formation, and their effect on the final separation of the mixture produced.

If a catalyst is required then the physical installation of this material, its removal and replacement, and its effect upon the fluid dynamics within the column become important additional operational and design considerations. The distillation column now becomes a countercurrent two-phase flow, fixed-bed reactor. Packed beds typically have a void fraction of 0.7 (even up to 0.95), whereas small catalyst particles result in a voidage of 0.3-0.4 which makes counter-current operation impractical. Therefore catalyst support structures must be designed and incorporated to provide a voidage of at least 0.5, and in addition allow for expansion and contraction of the bed, and provide a uniform catalyst spatial distribution. An alternative is to manufacture the catalyst in the shape of a distillation packing. For certain systems there are distinct advantages from employing reactive distillation, but their dynamics are complex and careful consideration of the operation and control are required in order to avoid potential difficulties.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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