Reactive distillation is a process in which a catalytic chemical reaction and distillation steps take place simultaneously in one single module. Reactive distillation combines two process stages and so is classed with the process intensification technologies. In the literature this integrated reaction-separation technique is also known as catalytic distillation or reaction with distillation. An overview on the current status of reactive distillation technologies, modeling, industrial applications, etc., can be found in literature .
For equilibrium-controlled reactions the major advantage of reactive distillation is the possibility to achieve higher conversion in the reaction, because it is no longer limited by the equilibrium between substrates and products. As the reaction proceeds the products are removed from the reaction mixture.
Reactive distillation is also more advantageous over conventional operating methods, such as a fixed-bed reactor connected to a distillation column, in which the distillate or bottoms have to be recycled after further separation steps for a total overall conversion. Besides higher conversion, further benefits of reactive distillation are :
• Possibility of using the heat of exothermic reaction to vaporize part of the liquid.
The reaction heat is integrated with the distillation process, which leads to energy savings by reducing reboiler duty. In addition, the direct use of the reaction heat without heat transfer across walls results is a higher efficiency.
• Lower capital investment, due to the combination of two process steps carried out in the same device.
• Increased product selectivity due to the removal of reactants or products from the reaction zone.
Catalytic chemical reactions which are limited by a chemical equilibrium can be improved by reactive distillation. On the industrial scale, this technology was applied mainly for etherification (synthesis of methyl tert-butyl ether (MTBE) ), esterification and alkylation (synthesis of ethylbenzene or cumene). An overview of applications can be found in literature [13, 14].
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