Модернизация насадочных ректификационных колонн с применением математической модели разделения многокомпонентной смеси

The scientific-engineering problem of mathematical modeling and calculation of separation of hydrocarbon mixtures in industrial columns with random and regular packings is solved. Multicomponent transfer is calculated using matrix of volume mass transfer coefficients and reverse-mixing (longitudinal mixing) of vapor and liquid streams is calculated using Peclet number with a reverse-mixing coefficient. The problem of development of variants of upgradation of oil-gas-condensate mixture stabilizing column in a refinery is discussed. The calculated concentration profiles of key components of the mixture are given. The required packing bed thickness is determined. The column operating conditions in the mixture load and composition range are stabilized after upgradation of the column with a new packing. Also solved is the problem of designing two industrial columns in the technological scheme of separation of benzene from stable condensate. The calculations enabled determination of the operating and design characteristics of the column using random Inzhekhim-2012 metallic packings. The results of materials balance calculation are presented and are compared with the column operation data.

Mixing characteristics of industrial columns in rougher circuit

The work in this paper is based on an industrial debutanizer column in a petroleum refinery located in Malaysia, which produces LPG (liquefied petroleum gas) as the top stream and light naphtha as the bottom stream. The controlled outputs, which are the critical product quality to be measured, are the concentrations of the top and the bottom streams. It is required to maintain the product quality for profitability, and recent trends in soft-computing have seen a plethora of methods developed for this purpose. However, due to practical constraints experienced by the plant that limit extensive plant step tests, data available for the development of the soft sensor for this industrial debutanizer column is scarce. Hence, in this paper, a neuro-fuzzy technique (ANFIS) is investigated and compared against the widely used ANN model for the special case of limited training data samples of the industrial debutanizer column. It is observed that in comparison to ANN, ANFIS has better generalization performance and can work well with limited training data samples. From the results, it was observed that the prediction performance of the ANFIS model generally improved the RMSE by approximately 10 times in comparison to that of ANN.

Data-based modeling of an industrial flotation column using classic and intelligent machine learning algorithms

In a market economy, gasoline hydrotreating at modern oil refineries is considered one of the most important technological processes. In conditions where the demand for high-quality gasoline on the world market is high, control of the gasoline hydrotreating process is a very pressing issue. As oil refineries strive to meet stricter environmental regulations, hydrotreating processes are becoming increasingly important. An automated control system has been developed for such a technological process. During hydrotreating, petroleum fractions selectively react with hydrogen in the catalyst presence at relatively high temperatures and medium pressure. This process converts unwanted aromatics, olefins, nitrogen, metals, and organic sulfur compounds into stabilized products. Some hydrotreated fractions may require additional processing to meet final product specifications. The presence of compounds containing sulfur, nitrogen, and oxygen in diesel and gasoline fractions is also extremely undesirable, as this leads to a deterioration in the characteristics of diesel engines and internal combustion engines. The composition of these compounds is also undesirable from an environmental point of view. As a hydrotreating result, the petroleum products quality increases. As the molecular weight of the fraction increases, the desulfurization rate decreases. The gasoline hydrotreating process continues, releasing a small amount of heat, which is used to compensate for heat losses to the environment. Keywords: hydrotreating process, oil refinery, petroleum products, automation system, control object, optimal control.

A rigorous and efficient distillation column model for engineering and training simulators

The article deals with the step-by-step construction of a digital model of hydrotreating and hydro-deparaffinization of diesel fuel in the Aspen Hysys V14 specialized software. The oil and gas industry today is a key sector of the Russian Federation economy, providing a significant part of energy resources and hydrocarbon raw materials for various industries. Digitalization plays an important role in the development of a modern and highly efficient Russian industry. Speaking about the stable and productive operation of oil and gas condensate refineries, we note the importance of hydrotreating and hydro-deparaffinization processes. Hydrotreating is a key process at any modern refinery, playing a crucial role in improving the environmental and operational quality of motor fuels. The reason for this is the tightening of environmental requirements for commercial fuels, the need to minimize the content of catalytic poisons (metals, phosphorus, arsenic, silicon) in straight-run fractions, and to improve the chemical and physical stability of fuels. At oil refineries, the dewaxing process is more often used to prepare components of oils and diesel fuels. Improvement of low-temperature properties allows oil products to be used in winter and in the regions of the far North. The feedstock of the modelled unit is straight-run diesel fraction 180-340 ⁰С, consisting mainly of paraffin and naphthenic hydrocarbons, containing mainly sulphur as heterocomponents. The created digital model allows estimating the efficiency of the plant operation mode, depending on the selected fuel grade (summer, winter, arctic). The model also makes it possible to predict the yield and quality of the product, which helps to optimize the process conditions to achieve the desired results.

The main types of petroleum components that are used in the manufacture of mixed motor gasolines are considered. For the manufacture of mixed motor gasolines, a low-octane base is used, to which high-octane components are added. In many cases, reformate (catalytic reforming gasoline) and isopentane (isopentane fraction) are used as high-octane components of mixed motor gasolines. Straight-run gasoline and stable gasoline are often used as the low-octane gasoline base of blended automobile gasolines. Reformate is a liquid mixture of aromatic and saturated hydrocarbons used as a high-octane component of automobile (aviation) gasolines and raw materials in the production of aromatic hydrocarbons (arenas). The reformate is obtained by catalytic reforming of straight-run gasoline fractions. Isopentane (2-methylbutane (CH3)2CHCH2CH3) is a colorless, flammable liquid. The technical product is a mixture of isomeric pentanes and boils within 24 - 34°C. The isopentane fraction can be isolated from gas gasoline, from gasoline direct distillation of oil and gasoline catalytic cracking. Straight-run gasoline (nefras) is obtained from the processing of crude oil or gas condensate, oil shale or coal, natural gas or oil and gas. Straight run gasoline contains light gasoline fractions of direct distillation of oil with a boiling range of 35 - 180°C. Gas gasoline (gas stable gasoline) is obtained from natural and petroleum gases containing vapors of gasoline hydrocarbons. To separate them, the gases are compressed and cooled (compression method) or absorbed with oil or activated carbon. Gas gasoline is similar in chemical composition to straight-run gasoline, but contains lighter hydrocarbon fractions. The article discusses the results of a study of the listed petroleum components of mixed gasoline by gas-liquid chromatography. This method allows you to establish the qualitative and quantitative composition of mixed motor gasolines and their components. It is shown that from readily available petroleum components (isopentane fraction, aromatic hydrocarbons and gas stable gasoline) without the use of sophisticated technological equipment, a gasoline mixture with high detonation resistance, which is falsified automobile gasoline, can be obtained by mixing method. When mixed in certain proportions of reformate, isopentane fraction and gas stable gasoline, it is possible to obtain marketable gasoline that will meet the requirements of regulatory documents for gasoline. The considered technology allows, when mixing commodity gasolines A-92 (A-95) with reformate, isopentane fraction and gasoline gas stable in the calculated proportions, to improve the operational characteristics (detonation resistance) of the obtained gasoline mixture or to increase the volume of the obtained gasoline mixture without improving its performance.

Results of experimental study of the effect of initial maldistribution of structured packing irrigation on efficiency of binary mixture separation are presented in this article. The studies were carried out in the experimental distillation column with the diameter of 0.9 m using the R114 and R21 freon mixture. Experiments were performed on the structured Mellapak 350.Y packing of stainless steel 316L, containing 19 layers with the total height of 4.016 m at the ratio of mole liquid and vapor flow rates L/V = 1 and 1.7, respectively, and the pressure in the upper part of the column ptop = 3 bars. Nonuniformity at the packing inlet was generated via the blocking of some holes in the liquid distributor. Here, we present some results on efficiency of mixture separation, pressure drop on the packing, distribution of local liquid flow rate under the packing over the cross‐section and on the column wall within the range of vapor loading factor (0.69 < Fv < 1.61 Pa0.5), as well as experimental data on distribution of local concentration of the low‐boiling component over the cross‐section and along the height of the structured packing. It is found out that significant maldistribution of mixture concentration and liquid flow rate over the cross‐section slightly changes along the height in the lower part of the column at a change in the degree of packing irrigation nonuniformity at the inlet. It is shown that efficiency of mixture separation depends considerably on the value of parameter L/V, vapor flow factor Fv, and size of the zone underirrigated by liquid at the inlet. In the studied range of liquid and vapor flow rates, the relative pressure drop on the packing does not depend on the ratio of liquid and vapor flow rates L/V and degree of irrigation maldistribution. © 2013 American Institute of Chemical Engineers AIChE J 60: 690–705, 2014

A theoretical analysis of the effect of velocity radial nonuniformity on nonstationary gas-solid adsorption processes in the column apparatuses is presented. The average concentration model, where the radial velocity component in the gas phase is equal to zero (in cases of a constant velocity radial nonuniformity along the column height), is used in the cases of an axial modification of the radial nonuniformity of the axial velocity components in the gas phase. The use of experimental data, for average concentrations in the gas phase at the column end, for a concrete process (physical or chemical adsorption), permits obtaining the gas phase model parameters related with the radial nonuniformity of the velocity. These parameter values allow using the average concentration model for modeling different adsorption processes.

In the chemical process industry, separation of mixtures into streams of high purity compounds is frequently necessary. Mixtures may originate from feedstock impurities, incomplete conversion of the reactants, and/or occurrence of undesirable side reactions. Feedstocks for the process industry are often complex mixtures such as mineral oil, coal, petroleum distillates, or vegetable fats. It is often desirable to separate the components of these mixtures prior to use. For the separation of mixtures a large number of processes and techniques have been developed. These are divided into two classes. The first is composed of separations based on differences in physiochemical properties, eg, boiling point in the case of distillation, and diffusivity in some membrane applications. The second class of separation is achieved by means of a selective chemical reaction. Examples include removal of acidic gases, carbon dioxide, and hydrogen sulfide, and hydrogen. This article discusses the second class with emphasis on contactor selection. The implementation of a chemical reaction is rarely simple. Reactor selection, regeneration of intermediate products, and possible degradation of the various components must be considered. The selection or design of a contactor is also complicated, even when the a classical contactor is used. For new processes, the various steps in the chemical reaction must be identified, eg, mass transfer, diffusion and chemical reaction, reaction schemes or networks, by product formation, etc, must all be considered. This identification is often too expensive to follow in commercial development so only partial knowledge of the elementary process may be obtained before proceeding. When more detailed knowledge of the reaction is available, selection or design of a special contactor exclusively devoted to the duty of the chemical separation process is possible. This article gives details for separation processes involving gas‐liquid systems, gas‐solid systems, and slurry contactors

The operation efficiency of distillation columns with structured packing is maximal if the distribution of countercurrent vapor and liquid film flows over the column cross-section on the mass transfer surface is most uniform. Various types of structured packing are widely used in distillation columns. Formation of the temperature field maldistribution in the column cross-section is observed in large-scale distillation columns. The sizes of large-scale maldistributions on zones are commensurate with the column diameter. The aim of this work is to obtain experimental data on the separation efficiency in large-scale distillation columns and dynamics of formation of large-scale maldistributions of local parameters of vapor and liquid in a countercurrent flow over a structured packing during mixture separation. Separation of the R114/R21 freon mixture was carried out on a structured Mellapack 350.Y packing with a diameter of 0.9 m and height of 2100 mm. The experiments were carried out under conditions of complete reflux in the range of reduced vapor velocity of 0.017 < K v < 0.035 m/s. Experimental data were obtained on the efficiency of mixture separation, pressure drop over the structured packing and parameters determining the formation dynamics of the large-scale temperature field maldistribution in the column cross-section. The presented experimental data will be used for the construction and verification of a new model of mass transfer and efficiency of mixture separation in large-scale distillation packed columns.

Roll-to-plate nanoimprinting with flexible stamps is a fabrication method to pattern large-area substrates with micro- and nanotextures. The imprint consists of the preferred texture on top of a residual layer, of which the thickness and uniformity is critical for many applications. In this work, a numerical model is developed to predict the residual layer thickness (RLT) as a function of the imprint parameters. The model is based on elastohydrodynamic lubrication (EHL) theory, which combines lubrication theory for the pressure build-up in the resin film, with linear elasticity theory for the elastic deformation of the roller material. The model is extended with inextensible cylindrical shell theory to capture the effect of the flexible stamp, which is treated as a tensioned web. The results show that an increase in the tension of the web increases the effective stiffness of the roller, resulting in a reduction in the RLT. The numerical results are validated with layer height measurements from flat layer imprints. It is shown that the simulated minimum layer height corresponds very well with the experimental results for a wide range of resin viscosities, imprint velocities, and imprint loads.

The divided wall column (DWC) can achieve sharp separations of three or more components in a single shell, substituting conventional sequences of two or more binary&lt;br /&gt; distillation columns, with lower expenses. Despite these advantages, DWC models are not available in commercial chemical process simulators. To simulate DWC, users must employ instances of conventional column model and couple them in different configurations. In this paper, a DWC model was developed in EMSO (Environment for Modeling, Simulation and Optimization). DWC model was then used for simulating the separation of an equimolar mixture of three hydrocarbons. Results show that, depending on the number of trays, DWC presented energy savings compared to two ordinary distillation columns. Better separation was obtained when the number of divided trays was close to half the number of total trays. However, the liquid and vapor flow rates split into the divided section play a key role in the separation.

Object of the research and modeling are the main columns of catalytic reforming unit of Atyrau Oil Refinery (AOR) that are operated under conditions of deficiency and inaccuracy of initial information. System of mathematical models of the columns being researched is developed on the basis of statistical and indistinct information. Structures of mathematical models of columns K-1, K-2 and K-3 are identified in the form of the regression and fuzzy regression equations, i.e. combined models of main columns of Leningrad-Germany (LG) catalytic reforming unit are composed.