Capabilities of cyclic distillation columns
The technological capabilities of cyclic distillation (CD) columns are extensive.
Their areas of application extend to oil refining, petrochemistry, the chemical industry, pharmaceuticals, perfumery, the food industry, isotope fractionation, and the production of high-purity substances.
CD can be used in both continuous and batch distillation. In batch distillation, the feedstock is charged in portions (batches), and the process stops once the still residue has boiled off. In continuous distillation, the feed mixture is supplied and the finished products are withdrawn steadily and around the clock.
Process areas utilizing cyclic distillation columns:
Fractional distillation: is a method of separating a mixture of liquid substances with different boiling points into individual components (fractions) through repeated evaporation and condensation.
Steam distillation: Distillation involving the passage of steam through the raw material, used to extract essential oils and thermolabile (heat-sensitive) substances.
Vacuum distillation: Distillation at reduced pressure, which lowers the boiling point of substances, allowing for the separation of compounds that decompose upon intense heating.
Azeotropic distillation: A specialized method for separating azeotropic mixtures (mixtures whose components cannot be separated by conventional distillation) by adding a third substance, a separating agent.
Extractive distillation: is a method for separating liquid mixtures with close boiling points or that are difficult to separate by conventional distillation; it involves adding a selective solvent to the mixture to alter the relative volatilities of the components.
Reactive distillation: is a chemical engineering process that combines a chemical reaction and mixture separation (distillation) in a single apparatus.
Isotope distillation: Isotope separation method based on the difference in saturated vapor pressure (or boiling points) of isotopically substituted molecules. The main characteristic of isotope distillation is the extremely low separation factor 𝜶. For most isotopic mixtures, it ranges from 1.001 to 1.05. The method is most effective for light elements.
CDs are characterized by the use of all available methods for intensifying the distillation process, aimed at increasing equipment throughput, improving component separation purity, and reducing energy consumption.
DWC (Dividing Wall Column): is an advanced fractional distillation method featuring a dividing wall that integrates the separation processes for multicomponent mixtures within a single vessel.
Heat-integrated Distillation columns (HIDiC) — represent advanced energy-saving equipment. Their primary objective is to drastically reduce the heat required for mixture separation by reusing the internal energy of process streams.
Heat pump. In distillation processes, a heat pump serves as a highly efficient energy recovery technology, enabling a reduction in heat consumption of up to 70–90% compared to traditional methods. Its primary function is to capture the latent heat of vaporization from the top of the distillation column (where the vapor condenses) and return it to the reboiler (evaporator) to boil the feed material.
External physical effects:
Applying ultrasonic oscillations disrupts the liquid boundary layer, increases flow turbulence, and accelerates mass transfer.
Vibrational and pulsational effects: Artificially inducing oscillations in the gas or liquid phase to enhance the renewal of the contact surface.
Intermediate draw-offs and heat input: Use of intermediate reboilers and condensers for a more efficient distribution of heat flows along the height of the column.
Cyclic distillation column diameter range: 200–2000 mm.
Cyclic distillation column tray count range: 5–50 trays.
Cyclic distillation column operating pressure range: 0.1–50 bar.
Cyclic distillation column operating temperature range: -50 to +300°C.
