A description of the technological scheme of the unit for separating the fraction of vacuum gas oil (FVG) is given, where the process of separation of heavy gas oil from FVG takes place in the column. The main focus of the work is on the design of a distillation column using the new structured roll packing. The fractional composition of the feedstock, by-product, light gas oil, and the target product, which is heavy gas oil, is presented. Requirements for the design of a structured packing in terms of pressure drop and separation efficiency are formulated. A structured roll packing with corrugations and rough surface having specific surface area of 300 m2/m3 is chosen. The diagram and photograph of the packing are presented. Comparative values of specific pressure drop for several structured packings are given. It is shown that the selected packing provides the lowest hydraulic resistance. For mathematical modeling and calculation of the multicomponent distillation process, a system of mass transfer equations with interfacial bulk sources of transfer components is used. In this case, for the conditional component, a fraction at the specified boiling points is used. As a result of solving the system of equations with boundary conditions, the profiles of the fractions along the height of the packed bed are found and the structural characteristics of the structured packing are selected that meet the requirements for the top and bottom of the column. Calculations of a vacuum distillation column with this packing are carried out and it is found that the bed height of 6 meters is sufficient to meet the requirements for the fractional composition of the upper and lower products, while meeting the pressure drop requirements. The developed scientific and technical solutions have been implemented at a refinery in Malaysia and correspond to the technical specifications for the design of the unit.

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Equations are derived for mean friction and heat transfer coefficients to solve problems of updating industrial plants for getting oil fractions based on application of approximate method of modeling momentum and heat transfer in heat exchangers with surface intensifiers. The Dyssler and Van-Driest turbulent boundary-layer model is used for the turbulent viscosity function for a flat smooth wall. An equation for the Stanton number is written using Chilton-Colborne hydrodynamic analogy and agreement with the known analogy is shown. Identical local properties of turbulent motion in a boundary layer on a plate and in a near-wall layer of a tube and the conservative properties of the laws of friction and heat transfer to turbulences, which are taken account of parametrically, are used for modeling momentum and heat transfer in channels with surface intensifiers. An equation for mean tangential stress in channels with intensifiers and, further, an equation for the Nusselt number is derived using a dissipative model. The results of calculations and comparison with the known experimental investigations are given for tubes with surface wire inserts, with spiral finning and rectangular projections for transformer oil at Reynolds numbers 200 < Re <2000. Thus, the adequacy of the developed mathematical model is proved in a wide range of operating and design parameters and thermophysical properties of fluids and gases. Further, the hydraulic resistance of the channel is the key experimental information about the object of modeling. Examples of use of mathematical model for designing and commissioning heat exchangers in petroleum fuels fractionating plants at industrial enterprises in the Russian Federation and abroad are given.