1.1 Reactive distillation (RD)

Chemical engineering deals with the conversion of raw material into products via a chemical unit process or unit operations. Manufacturing of various chemicals like esters, ethers, cumene, petroleum processing unit, etc. required a reactor followed by separator such as a distillation unit to separate the required product from other constituents on the basis of relative volatility [1]. There are various constraints on this type of processing like more space required for the installation of the unit, higher cost, more energy input requirement, and reduced selectivity. Specifically the conversion limits for reversible reactions are difficult to overcome toward highest purity of product because once the equilibrium is achieved in the system, no more reactant will be converted into products. In view of all these constraints, reactive distillation emerged as a novel technique of process intensification in which reaction and separation of product take place simultaneously in a single column [2].

homogeneous and heterogeneous catalysts. However, hydrodesulfurization of light

Process Industrial location

Synthesis of acetates Europe Hydrolysis of methyl acetate Europe and Asia Synthesis of methylal Europe and Asia Removal of methanol from formaldehyde Europe Fatty acid ester Asia

Reactive Distillation: Modeling, Simulation, and Optimization

DOI: http://dx.doi.org/10.5772/intechopen.85433

CDTECH, the major commercial process technology provider, licensed up to now over 200 commercial-scale processes. Sulzer reports the commercial application of reactive distillation as synthesis of ethyl, methyl, and butyl acetate, hydro-

formaldehyde, and formation of fatty acid esters. Commercial reactive distillation

Reactive distillation (RD) is a hybrid combination of reaction and separation in a single vessel. The first patent for this process route was out in the 1920s, but little was carried out till 1980 by the Eastman Company who synthesized methyl acetate for the first time using this technique. The following reactions have shown potential

In esterification reaction, alcohol and acid react to form an ester. Esters are

ROOR' <sup>þ</sup> NaOH➔ROONa <sup>þ</sup> HOR'

Transesterification reaction in general can be represented as the reaction between triglyceride and alcohol to produce alkyl esters and glycerol. The best example is a synthesis of biodiesel using transesterification. Commercially, no industrial unit has been reported on synthesis of biodiesel in RD, but the literature shows that pilot-scale synthesis is possible. This process occurs by reacting the vegetable oil with alcohol in the presence of an alkaline or acidic catalyst.

The main application of esters is in the synthesis of artificial flavor and essence and solvent for oil, gum, fat, and resins. They are also used as plasticizers. Esterification is the oldest reaction carried out in a reactive distillation column. For example, in conventional methyl acetate production, the yield of methyl acetate is low because of low boiling azeotrope formation. This constraint is removed in RD and almost pure methyl acetate can be collected. Fatty acid esters are natural chemicals used, among other things in cosmetics; plastics and surfactants were also reported

oil fractions has been carried out commercially for diesel deep hydrodesul-

lysis of methyl acetate, synthesis of methylal, removal of methanol from

application with Katapak licensed from Sulzer is tabulated in Table 1.

3. Industrial perspective of reactive distillation

chemical compounds having pleasant fruity odor.

to be synthesized in reactive distillation.

3.2 Transesterification

93

furization.

Commercial application of reactive distillation.

Table 1.

for reactive distillation:

3.1 Esterification

Figure 1. Schematic diagram of reactive distillation column (RDC).

In the case of reactive distillation, total capital cost is reduced due to two combined process steps held in the single unit. This kind of integration is also beneficial in reducing pump cost and other instrumentation cost. The saving in total energy cost is due to exothermic nature of many chemical reactions which in turn are beneficial in providing heat for separation of components simultaneously [3–10]. The schematic diagram of reactive distillation column is shown in Figure 1.
