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The actual task of the state is to increase the energy efficiency of the oil refinery. The object of research is a vacuum distillation unit, including a preheating unit for raw materials and a furnace for heating fuel oil before the column. Pinch analysis allows to analyze and optimize a large number of heat flows. In this study the analysis and enhancement of efficiency of the research object is carried out by enthalpy pinch analysis. In order to reduce the heat load of the furnaces, the additional flows were introduced into the heat exchange system of the oil heating unit. Parametric optimization of the new heat exchange system was carried out. The minimum needs of the heat exchange system in external energy carriers are determined. An enthalpy cascade of the heat exchange system has been constructed, which clearly shows the distribution of heat between each heat flow of the system. In the analysis of the energy efficiency of a furnace, an important point is the determination of the optimal heat capacity of the combustion products. In this work, we have determined the optimal flow heat capacity, at which the heat loss with the exhaust gases is minimal. As a result of the studies carried out, the efficiency of the fuel oil preheating unit has been increased by maximizing heat recovery, and the cost of external energy carriers has been minimized. By reducing heat loss with flue gases, it was possible to increase the efficiency of the furnace.

Objective To solve the serious scaling problem of the atmospheric and vacuum distillation unit during operation. Methods A new dispersive anti-scaling agent HK-l 7DC was added at the initial and end stage of the operation of the unit to evaluate its removal and anti-scaling effect. Results After adding the agent, the flow rate of the reflux in the third middle section of vacuum tower gradually increased and remained between 120 -12:5 t/h, it is 20 - 2:5 t/h higher than before adding the agent, and the oil heat exchange temperature difference at the bottom of the primar y distillat ion tower was significantly improved, basically maintained at 61- 63 'C at the end of the unit operation. During the initial operation of the unit, it was 12 - 2'1 °C higher than before, the flow rate of the reflux in the third middle section of vacuum tower was maintained at 21 1:5- 2:52 t / h, compared with the initial period of operation before maintenance, it increased by 12:5 t / h, and the temperature difference of oil heat exchange at t he bottom of the primary distillation tower was maintained at 66 - 69 'C, compared with the initial period of operation before maintenance, it increased by 16 'C. Conclusions .At high temperature, the anti-scaling agent showed good scale removal and anti-scaling performance, the long-term operation effect was stable and had no adverse effect on the product quality. It solved the scaling problem of atmospheric and vacuum distillation unit for a long time. [ABSTRACT FROM AUTHOR]

The deep-cut vacuum distillation can improve the light oil yield and reduce the secondary processing capacity of residual oil, which is an important development direction for refinery to improve product structure and economic benefits. According to the characteristics of two-stage vacuum distillation unit, the feasibility and effect of deep-cut by increasing the outlet temperature of vacuum heater were analyzed. Results showed that the peak heat flux exists in the middle and lower part of each tube of the furnace. The difference between the maximum and minimum oil film temperature on the fire side was about 20 °C and that on the back fire side was 6 ~ 8 °C, due to the uneven heat flux. Based on the outlet temperature of the vacuum heater at 400 °C, the total pulling out rate increased by 2.05, 4.01 percentage points respectively when the temperature of the furnace outlet was increased to 410 °C and 420 °C . According to the processing capacity of 8.0 MM TPY, the annual economic benefits can be increased by 6.56 million yuan and 12.83 million yuan respectively. Therefore, the economic benefits of the deep-cut vacuum distillation are very considerable. [ABSTRACT FROM AUTHOR]

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%. [ABSTRACT FROM AUTHOR]