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The purpose of this study was to analyze the functioning of the vacuum distillation unit of a mini-refinery and to develop recommendations for improving the vacuum overhead system with the aim to reduce the cost of creating and maintaining a vacuum in the fuel oil separation column. A calculation model of the vacuum unit was developed in the Unisim Design R451 software package, which was identified by comparing the calculated data with the data from an industrial study for two operating modes of the installation. Replacing the existing steam-ejector pump with a liquid-ring vacuum pump was proposed. A numerical experiment was carried out on the developed model, the purpose of which was to determine the “bottlenecks” of the scheme. The peculiarity of the experiment was that the vacuum column and the vacuum overhead system were considered as a single whole. As a result, it was determined that the “bottleneck” is the condenser, which was proposed to be replaced. During the technical and economic analysis, two possible vacuum overhead system schemes were considered; according to the results, it was determined that the vacuum overhead system scheme based on a liquid-ring vacuum pump will help reduce operating costs by 78%.

The article presents the methodology of coupled modeling of the main blocks of a chemical-technological system operating under vacuum. The system analysis of vacuum blocks is carried out and the basic rules of technological calculation are formed, in which the evacuated technological object and the vacuum overhead system are considered as a single system with inter-dependent elements. The presented methodology was applied when calculating the vacuum block of the primary oil refining process of a mini-refinery working on fuel oil, as a result of which an integrative characteristic of the block was compiled, which takes into account the mutual influence of the vacuum system and the technological object on the residual pressure at the top of the vacuum column. The adequacy of the developed model was ascertained by comparing with industrial research data. In line with the proposed methodology, numerical experiments were carried out accordingly in which the temperature of the service liquid being fed into the pump was changed. The results of the calculations showed that, achieving the given project Pressure under the current block component setup (P= 40 mm Hg) was not possible as a reason of the increased resistance in the shell side of the condenser.

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Production processes sometimes are accompanied by the release of hazardous substances, the composition and volume of which is determined by the production technology. When designing ventilation systems for paint departments, special attention is paid to safety concerns, since all paint coatings are corrosive and flammable substances. Besides, solvent vapors are explosive. For local ventilation of painting chambers, it is rational to use safe exhaust systems with an ejector, which works sturdily, regardless of the release of flammable and explosive impurities. The ejector is simple in design and can operate in a wide range of changes in the parameters of the state of airflow. The model of the ejection unit is synthesized using the universal modeling package ChemCad, which contains a highly developed database of airflow parameters, which allows for solving various applied problems. Numerical modeling was carried out using the software package - FLUENT. In work, a calculation was carried out and a low-pressure ejector was designed for a typical painting booth. The calculation results are presented in the form of graphs and tables of pressures, velocities, flow rates in characteristic sections, pressure losses in the sections of the ejector installation.The ejection coefficient was also calculated.