Separation of mixtures into pure components is necessary in the industry. Especially for reusing. However, most of these mixtures contain azeotropes which makes separation by distillation impossible. Azeotropes are involved in common chemical processes including the production of methyl acetate, tetrahydrofuran, ter-methyl amyl ether, isopropanol, and vinyl acetate. Additionally, due to their growing popularity, biofuel processes typically produce fermented products that form azeotropes with water which is abundant in the fermentator. Among those products, ethanol is the most important example, due to its excellent properties as alternative fuel. However, compounds such as butanol also form aqueous azeotropic mixtures.
There are lot…show more content… This method does not require an entrainer. When this occurs, a two-column system can be used to achieve the desired separation. The pressure change in two columns effect the vapor-liquid equilibrium which affect the chance of separating by distillation. At times a simple change in pressure can change the azeotrope composition. The azeotrope will come out of the top and the product from the bottom if the azeotrope has lower boiling point. If the azeotrope has higher boiling point, the azeotrope comes out of the bottom and product from the top. The azeotrope is then fed to the second high-pressure column in which a similar separation occurs, except now the other component is removed from one end of the column and a stream with composition close to the high-pressure azeotrope is removed from the other end. This azeotropic stream is fed back to the low-pressure column. (Anon,…show more content… Some ionic liquids have higher selectivity tthan common organic solvents. Homogeneous Azeotropic distillation
The most general definition of homogeneous azeotropic distillation is the distillation of any mixture containing one or more azeotropes into the desired pure component or azeotropic products without exploiting any liquid-phase immiscibility that might be present.(GERSTER JA 1969). The entrainer is completely miscible with the components of original mixture and the distillation is carried out in a single-feed column.
• Determining the desired separation objective
• Sketching the residue curve map for the mixture
A feasible distillation sequence for homogeneous mixture has the desired products lie in the same distillation region and then can be synthesized by superimposing material balance lines onto the distillation residue curve map. Figure 2: Homogeneous azeotropic distillation in a single feed