RU2394873C2 - Procedure for intensification of process of preliminary distillation of oil - Google Patents

Abstract

FIELD: gas-and-oil industry.

SUBSTANCE: invention refers to oil processing industry. The invention refers to procedure for intensification of the process for preliminary distillation and for increased depth of light fractions of oil withdrawal by means of introduction of surface active substance into a crude flow coming to a rectifying column. Surface active substance is potassium salt of synthetic fat acid - RCOOK, where R=C₉÷C₁₅, taken at amount 20÷30 ppm.

EFFECT: increased depth of light fractions withdrawal.

1 tbl, 4 dwg

Description

The invention relates to methods for intensifying the process of primary distillation of oil and can be used in the oil refining industry.

Known methods of oil refining in primary distillation plants using an evaporating agent, described in [I.A. Alexandrov. Distillation and rectification. - M .: Chemistry, 1981. - 32 p.].

One of the main problems of the primary distillation of oil is the insufficient depth of selection of light fractions from oil [Refinery Handbook: Handbook. / Ed. G.A. Lastochkina, E.D. Radchenko, M.G. Rudina - L .: Chemistry, 1986. - 648 p., Ill.]. The content in the fuel oil of fractions up to 350 ° C reaches 10-12% [M.E. Levinter, S.A. Akhmetov. Deep oil refining. - M.: Chemistry, 1992. - 224 p.].

The generally accepted method of increasing the selection of light fractions in the process of primary distillation of oil is the use of an evaporating agent, which is used as water vapor. When water vapor is introduced into the bottom of the atmospheric column, the partial pressure of hydrocarbons decreases and, as a result of bubbling, the interface between the liquid and vapor phases increases.

The disadvantages of the known methods of distillation with steam include: increased energy costs (heat and cold) for distillation and condensation; increasing the load of the columns in pairs, which leads to an increase in the diameter of the apparatus and the entrainment of liquids between the plates; increase in resistance and increase in pressure in the column and other devices; watering of oil products and the need for their subsequent drying; enhanced corrosion of oil equipment; the formation of large quantities of contaminated wastewater [M.E. Levinter, S.A. Akhmetov. Deep oil refining. - M.: Chemistry, 1992. - 224 p.].

When considering the process of rectification of oil and its fractions, thermodynamic relations are used, but the dynamics of the process, which is affected by the size of the interface between the liquid and vapor phases, are not taken into account.

One of the main tasks of the distillation of oil and its fractions is to increase the depth of selection of light fractions from the bottom residue.

The problem is solved by introducing a surfactant of a potassium salt of synthetic fatty acid - RCOOK, where R = С ₉ ÷ С ₁₅ , in an amount of 20 ÷ 30 ppm, into the feed stream entering the distillation column, which ensures the selection of light fractions from the bottom residue , the desired result is achieved due to a decrease in the time required for evaporation and boiling of the remaining part of the light fractions in the still part of the distillation column.

The specified technical result is achieved due to the fact that during the distillation of oil and its fractions, energy is consumed, characterized not only by the latent heat of evaporation of light fractions and bottoms, but also by work on creating an interface between the liquid and vapor phases, according to the formula

A = S

where A is the work spent on creating the interface between the liquid and vapor phases;

S is the total surface of the vapor phase bubbles;

δ is the surface tension at the interface between the liquid and vapor phases.

The evaporation process was studied in detail by D.A. Frank-Kamenetsky in [D.A. Frank-Kamenetsky. Diffusion and heat transfer in chemical kinetics. - M .: Nauka, 1987. - 502 p.], Based on his work, it follows that under condition A = const, with a decrease in surface tension at the interface between the liquid and vapor phases (δ), the total surface of evaporation and boiling of the liquid phase increases ( S). With an increase in the interface between the liquid and vapor phases, the rate of evaporation and boiling increases proportionally.

Table 1 presents the test results of the effect of the surfactant of the potassium salt of synthetic fatty acid RCOOK, where R = C ₉ ÷ C ₁₅ , on the surface tension of n-hexane at the interface with air.

Table 1 The effect of surfactant RCOOK on the surface tension of n-hexane at the interface with air Additive concentration, ppm

The surface tension of n-hexane at the interface with air,

0 17.90 5 13.92 10 11.93 fifteen 16.90 twenty 17.90

From the data in table 1 it follows that the introduction of RCOOK reduces the surface tension of n-hexane at the interface with air, which reduces the work spent on the formation of a unit of a new surface at the interface between the liquid and vapor phases, which leads to accelerated evaporation and boiling.

; 2 - рассматриваемая зависимость при скорости разгонки

; 3 - рассматриваемая зависимость при скорости разгонки. На фиг.2 представлена зависимость увеличения выхода фракций от расхода RCOOK при разгонке Шаимской нефти по методу Энглера на аппарате АРНС Э при нагреве до 300°С, где цифрами обозначены: 4 - рассматриваемая зависимость при скорости разгонки

; 5 - рассматриваемая зависимость при скорости разгонки

; 6 - рассматриваемая зависимость при скорости разгонки. На фиг.3 представлена зависимость увеличения выхода бензиновой фракции от расхода RCOOK при разгонке бензиновой фракции Шаимской нефти по методу Энглера на аппарате АРНС Э при нагреве до 100°С, где цифрами обозначены: 7 - рассматриваемая зависимость при скорости разгонки

; 8 - рассматриваемая зависимость при скорости разгонки

; 9 - рассматриваемая зависимость при скорости разгонки

.Consider the effect of RCOOK on the primary distillation process. The results of a study of the effect of RCOOK on the rate of evaporation and boiling of Shaim oil under distillation conditions according to the Engler method on the ARNS E apparatus are shown in FIGS. 1 and 2, and on the rate of evaporation and boiling of oil fractions, straight-run gasoline fraction of Shaim oil, in FIG. Figure 1 shows the dependence of the increase in the yield of fractions on the consumption of RCOOK during the distillation of Shaim oil according to the Engler method on the ARNS E apparatus when heated to 100 ° C, where the numbers denote: 1 - the considered dependence at the speed of acceleration

; 2 - considered dependence at the speed of acceleration

; 3 - considered dependence at the speed of acceleration. Figure 2 shows the dependence of the increase in the yield of fractions on the consumption of RCOOK during the distillation of Shaim oil according to the Engler method on the ARNS E apparatus when heated to 300 ° C, where the numbers indicate: 4 - considered dependence at the speed of acceleration

; 5 - considered dependence at the speed of acceleration

; 6 - considered dependence at the speed of acceleration. Figure 3 shows the dependence of the increase in the yield of the gasoline fraction on the consumption of RCOOK during the distillation of the gasoline fraction of Shaim oil according to the Engler method on the ARNS E apparatus when heated to 100 ° C, where the numbers denote: 7 - considered dependence at the acceleration speed

; 8 - considered dependence at the speed of acceleration

; 9 - considered dependence at the speed of acceleration

.

The dependences of figures 1, 2 and 3 have a maximum extremum, which increase with increasing speed of distillation. For Shaim oil, the maximum extremum is observed at an RCOOK flow rate of 27 ppm, and for a straight-run gasoline fraction of Shaim oil, the maximum extremum is observed at an RCOOK flow rate of 23 ppm.

With an optimal flow rate of RCOOK, an experiment was carried out on the effect on the rate of evaporation and boiling under conditions of a clear rectification of Shaim oil on an ARN 2 apparatus, the results of which are presented in Fig. 4. Figure 4 shows the dependence of the increase in the yield of fractions of Shaim oil at a flow rate of RCOOK 27 ppm on the distillation rate under conditions of clear distillation on an ARN 2 apparatus, where the numbers denote: 10 - the considered dependence when heated to 100 ° C; 11 - the considered dependence when heated to 200 ° C.

From the data of figure 4 it follows that with the introduction of the surface-active substance RCOOK with an increase in the rate of selection of fractions, their yield increases upon acceleration to the same temperature.

The method is as follows: the RCOOK surfactant is introduced into the feed stream of the distillation column in an amount of 20-30 ppm, which leads to accelerated evaporation and boiling of the bottoms product, due to an increase in the surface at the interface between the liquid and vapor phases. Obtaining a developed surface helps to reduce the time interval required to approach the state of thermodynamic equilibrium. The selection of distilled fractions from the potential increases, reducing the loss of distilled fractions with bottoms product during the distillation of oil of a diesel fraction with fuel oil.

Claims (1)

A method of intensifying the primary distillation process and increasing the depth of selection of light oil fractions by introducing a synthetic fatty acid surfactant, RCOOK, into the feed stream entering the distillation column, where R = C ₉ ÷ C ₁₅ , taken in an amount of 20 ÷ 30 ppm ^-1 .

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