**1961 year** (Canon M.R.) – suggested the way of phase interaction, for which during the passage of vapor through the column the liquid doesn’t overflow from tray to tray and upon liquid overflow it doesn’t mix on adjacent trays (cyclic process) [1].

**1966 year** (Sommerfeld T.) – was shown that upon comparison of stationary and cyclic processes both by the time of mass transfer on the tray and by the phase interaction nature, the cyclic process is similar to the stationary process upon single-direction movement of liquid on adjacent contact levels and perfect displacement by liquid and vapor. The longing for obtaining of separation efficiency above theoretical stage of McCabe-Thiele promoted the development of constructive solutions for stationary mode towards longitudinal sectioning on the tray, and for cyclic regime – provision of liquid overflow on the trays with minimum mixing of adjacent trays [2].

**1966 year** (Robinson R.G.) – performed a theoretical analysis to demonstrate the advantages of cycled mass transfer operations, in which only one phase flow sat any given time and where the phases use the same inter stage flow pass ages during the irrespective flow periods [3].

**1977 year** (Rivas O.R.) – showed that simple analytical equations can be used to calculate the ideal number of trays for cyclic countercurrent processes such as cyclic distillation. These equations represent an accurate solution of the set of ordinary differential equations that result from making material balances on each plate of a cyclic column. They simplify greatly the preliminary design of these columns since they are easy to use and similar to the well known Kremser-Souder-Brown equations that are used in conventional processes [4].

**1978 year** (Furzer I.A.) – reported the discrete residence time distribution of a distillation column operated with microprocessor controlled periodic cycling. The fluid flow in a distillation column was studied by measurements of the discrete residence time distribution. The column was fitted with 5 sieve plates of 100 mm diameter, 14.8% free area, 6.1 mm hole diameter, and 635 mm plate spacing. The periodic control was obtained using a JOLT microprocessor system. An analysis of the discrete residence time distribution yielded the parameters in the (2S) model that describes the fluid flow. Modifications to the column internals were required to alter these parameters, if the maximum separation improvements were to be obtained [5].

**1985 year** (Matsubara M.) – used cycling operation to emphasize the advantages of relay feedback periodic control compared to the forced oscillation scheme. When combining cycling and stepwise operation modes up to 50% energy reduction was observed, compared to conventional continuous column. The cycling operating mode was proved experimentally on a five-stage water–methanol mixture [6].

**1986 year** (Maleta V.N.) – suggested the theoretical stage model with perfect displacement and theory of operation line for cyclic distillation system [7].

**2005 year** (Maleta V.N.) – first industrial scale using Maleta trays in productions ethanol food grade, Ukraine. The column diameter is 400mm. The number of distillation trays is 15 pcs. Capacity of column is 0.5 m3/hr. It was first column in the world that operation in cyclic mode/ cyclic mass transfer (cyclic distillation technology) in industrial scale [8].**2014 year** (Anton A. Kiss.) – performed a mathematical model catalytic cyclic distillation process (reactive cyclic distillation). By means of a case study involving a simple reaction system, the model is used to demonstrate the key benefits of this operation mode. In addition, the synthesis of dimethyl ether by catalytic cyclic distillation is considered, for which a design algorithm is suggested [9].

**2014 year** (Maleta V.N.) – first industrial scale in the world of tray dividing wall column in cyclic operation. Columns diameter is 1500/1700mm. Number of distillation tray 42 pcs. Capacity of the columns is 25m3/hr to 1700mm.

to be continued…

**References:**

1. Canon M.R. and I.R. McWhirter, “Controlled cycling distillation,” Ind. Eng. Chem. 53, 632-634 (1961).

2. Sommerfeld T., N. Verle Schrodt, Paul E. Parisot, Henry H. Chien, “Studies of Controlled Cyclic Distillation: I. Computer Simulations and the Analogy with Conventional Operation Jude, Separation Science and Technology, Volume 1, Issue 2, 245 – 279 (1966).

3. R.G. Robinson, A.J. Engel, Analysis of controlled cycling mass transfer opera- tions, Industrial and Engineering Chemistry 59 (1967) 22–29.

4. O.R. Rivas, An analytical solution of cyclic mass transfer operations, Indus- trial and Engineering Chemistry—Process Design and Development 16 (1977) 400–405.

5. I.A. Furzer, Discrete residence time distribution of a distillation column oper- ated with microprocessor controlled periodic cycling, Canadian Journal of Chemical Engineering 56 (1978) 747–750.

6. M. Matsubara, N. Watanabe, H. Kurimoto, Binary periodic distillation scheme with enhanced energy conservation – II: Experiment, Chem. Eng. Sci. 40 (1985) 755–758.

7. Малета В.Н., Таран В.М. и Дубовик В.А., “Сопоставление циклического и стационарного процесса ректификации,” Известия вузов СССР. Пищевая технология 6, 52-55 (1986).

8. V.N. Maleta, A.A. Kiss, V.M. Taran, B.V. Maleta, Understanding processintensification in cyclic distillation systems, Chem. Eng. Process. 50 (2011)655–664.

9. C. Patrut, C. S. Bildea, A. A. Kiss, Catalytic cyclic distillation - A novel process intensification approach in reactive separations, Chemical Engineering and Processing: Process Intensification, 81, 1-12, 2014.