SU1364353A1 - Method of controlling the process of primary refining of oil - Google Patents

Abstract

The invention relates to a method for controlling the process of primary oil refining in a COMPOSITE distillation column used in the petroleum and petrochemical industry, and improves the accuracy of controlling the recovery temperatures of petroleum products. The method consists in that in a COMPLEX column consisting of simple columns, the flow rate of the circulating irrigation of each previous simple COLUMN is adjusted depending on the temperature of the upper sections of the simple columns, corrected for the flow rate of the circulation irrigation of each subsequent simple column. 1 IL. and S (L

Description

The invention relates to the field of control of refining processes and petrochemicals and can be used in the automatic control of the process of primary oil refining in a complex distillation column with blank plates.

The purpose of the invention is to improve the accuracy of temperature control of boiling of oil products obtained in a complex distillation column with deaf plates.

The drawing shows a schematic diagram of the implementation of the method.

 The method is carried out in the following manner.

The process of refining oil proceeds in a complex distillation column with three deaf plates, consisting of sections 1-8. Sections 1 and 6 form the upper simple column, sections 2 and 7 form the upper intermediate simple column, sections 3 and 8 form the lower intermediate simple column, and sections 4 and 5 form the lower simple column. The complex column under consideration is designed to separate partially stripped oil coming through line 9 into five oil products: gasoline, discharged through line Yu, kerosene, discharged through line 11, winter diesel fuel discharged through line 12, summer diesel fuel discharged through line 13, the fuel oil discharged through line 14 and an additional heavy shoulder strap, which is discharged in certain modes through line 15.

The raw material of the bottom simple column (sections 4 and 5), as well as the entire complex column, is stripped oil. The raw material of the lower intermediate simple column (sections 3 and 8) is a mixture of steam diesel fuels, kerosene and gasoline coming from section 4 to section 3 through a fluid-filled selection plate of summer diesel fuel. The raw material of the upper intermediate column (sections 2 and 7) is a mixture of vapors of winter diesel fuel, kerosene, and gasoline, coming from section 3 to section 2 through a fluid-tight selection plate of winter diesel fuel. The raw material of the upper simple column (sections 1 and 6) is a mixture of kerosene and gasoline vapors, coming from section 2 to section 1 through a liquid kerosene sampling plate.

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The liquid from the upper section 1 of the upper simple column flows into its lower section 6 through line 16, and the vapors from the lower section 6 to the upper part return through line 17.

Similarly, the appointment of lines 18-21.

Line 21 serves to return the vapors from section 8 to section 3. The upper 10 part of section 4 of the lower simple column and the lower part of section 5 are combined into a simple column directly.

Superheated water vapor IF is supplied to the lower parts (sections) of simple columns 6-8 and 5 through lines 22-25, respectively.

Irrigations are fed to the upper sections 1-4 of simple columns along lines 26-20 29, respectively. The irrigation liquid of the upper intermediate column, the lower intermediate and lower simple columns is taken from these same columns along the line} m 30-32 and cooled 25 in heat exchangers 33-35. Irrigation of section 1 is formed from the vapors discharged from it through line 36, condensed in the condenser - cooler 37, and the condensate is supercooling for 30 s and accumulates in the reflux tank 38 ..

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The flow rates of superheated water vapor in the lower parts of simple columns (in sections 6 and 5) are carried out using flow meters 39 and 40, and the regulation is carried out using regulators 43-46. The temperature measurement of the upper sections 1-4 of simple columns is carried out using 47-50 temperature sensors, and the regulation using regulators 51-54, the outputs of which change the irrigation flow rates supplied on lines 26-29, respectively.

Periodically, manually or automatically continuously carry out the sampling and analysis of samples of petroleum products withdrawn from the column along lines 10- .14 (and 15), determine their boiling out temperatures, and regulate them by changing the setpoint of the temperature regulators of the upper sections of simple columns and flow regulators 43-46 water vapor.

Irrigation costs are measured using flow meters 55-58 and their output signals are passed through blocks 59-62 to multiply by a constant factor. The output of block 59 to multiply by a constant coefficient is fed to the first positive input of adder 63, the output of block 60 to multiply by a constant factor - to the first positive input of the adder 64, and the output of the block 61 multiplied by a constant coefficient - to the first positive input of the adder 65 To the second positive inputs of the adders 63-65 receive the outputs of the adders 64 and 65 and block 62, respectively. The outputs of the accumulators 63-65 and the block 62 multiplied by a constant coefficient are fed to the variable inputs of the flow rate controllers 66-69, respectively, and the Target of these controllers are fed to the temperature controllers 51-54, respectively.

Thus, the change in the irrigation flow rate of some particular simple column is additionally adjusted depending on the measured irrigation costs of simple columns located in the complex column below this simple column.

For example, if the irrigation flow rate of the bottom simple column does not change, then the output of the flow meter 58, and hence the unit 62 multiplied by a constant factor, is constant. If the temperature changes under the sampling plate of winter diesel fuel (the plate separating sections 3 and 2) measured by the temperature sensor 49, then the output of the temperature controller 53 and the flow regulator 68 also changes, resulting in a circulating flow rate irrigation on line 31-28 is changing. This is done; controlling the temperature of the top of a simple distillation column, consisting of sections 3 and 8, by changing the flow rate of the reflux fed to this column. The temperature of the upper part of a simple column consisting of sections 2 and 7 and a simple column consisting of sections 1 and 6 are likewise regulated.

If the flow rate of the lower circulating reflux changes, and the temperature measured by the temperature sensor 49 remains constant, then one of the adder’s components, 65, increases, as well as the output of this adder. Now in the chamber. Variable 68 flow control signal is larger than in the chamber.

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The task, and as a result, the flow controller 68 closes the valve on line 28. This adjusts the flow rate of the reflux to the upper section of the simple column, depending on the irrigation costs of the simple columns located in the complex column below this one.

If, during the adjustment process, the irrigation flow through line 29 is changed, not only the temperature of the upper part of the simple column consisting of sections 4 and 5 is altered, but also the flow of pairs passing from section 4 to section 3.

This is a feature of the rectification process in any method of regulation. As a result, the temperature of the upper part of a simple column consisting of sections 3 and 8 changes. Thus, if the irrigation flow through line 29 decreases, then the temperature measured by temperature sensor 50 also increases. and a stream of vapors reaching temperature sensor 49. One in the proposed method simultaneously reduces the output of the block 62 multiplying by a constant coefficient and the adder 65, as a result of this, the flow controller 68 opens the valve on the line 28 and in the zone where the temperature sensor 49 is located, an increased flow occurs towards the increased vapor (heat) consumption. the flow of irrigation (cold) and the change in the temperature of the top of section 3 in response to a change in temperature of the top of section 4 does not occur.

As a result, stabilization of the separation mode is improved and boil-off temperature control is improved.

A similar effect for the top of section 2 is provided by the connection of the output of the adder 65 to the input of the adder 64, and for the top of section 1 - to the connection of the output of the adder 64 to the input of the adder 63. 46, the consumption of water vapor in their lower sections is modified by the results of determining the boiling temperature of samples of petroleum products taken from line 10-15.

The levels in the reflux tank 38 and in the lower sections of the simple columns are maintained by means of regulators 70-74, varying the flow rate along the lines 10-14. Product diversion is heavier than summer diesel, according to

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The SRI 15 is controlled by the controller 75, the flow measurement being carried out by the flow meter 76.

All the above-mentioned flow and level temperature sensors are generally accepted. All the above-mentioned regulators, adders and blocks multiplied by a constant coefficient are also commonly used pneumatic blocks of the Start system (PR3.31, PF1.1, PF1.9),

The proposed method increases precisely the dynamic accuracy of stabilization of mode parameters and product quality indicators, and the application of this method gives a particularly large effect on plants operating under conditions of large and frequent disturbances in the composition and loading of raw materials and large disturbances from the heat sink (refrigerators) equipment. . Testing this method at one of the primary processing facilities allowed us to reduce the temperature fluctuations of the upper sections of simple columns located in the lowermost one.

example. The temperature in the upper section of the lower intermediate simple column was 182 ° C, and the temperature in the upper section of the upper intermediate simple column was 120 ° C. .After setting the installation manager, the setting of the temperature controller of the upper section of the lower intermediate simple column was reduced to 174 ° C (that is, 8 ° C).

In the case of applying the known method, the transient process was completed in 30 minutes. The minimum value reached 167 ° C (6 minutes after changing the setpoint). This transient process was accompanied by a change in the temperature of the upper section of the upper intermediate simple column, which dropped to 114 ° C (in the seventh minute after the setting was changed by the lower regulator). The temperature stabilized again after 25 minutes.

At the same time, the irrigation flow rate of the lower intermediate simple column, which before stabilization of the setpoint was 280 m h, stabilized at 300 m / h, reached 305 m / h during the adjustment process.

The irrigation flow rate of the upper intermediate simple column changes from 164 to 140 m / h, reaching a minimum value of 132 m / h in the seventh minute.

In the case of applying the proposed method, the same change in the task of the same controller from the same

The initial state, which caused almost the same changes in the temperature of the upper section of the lower intermediate simple column and the flow rate of irrigation to it, was accompanied by a completely different mode change in the upper intermediate simple column.

Here, the temperature did not rise above and did not fall below 119 C. The process ended after 16 minutes. The new value of irrigation flow is almost the same as. and in the first case, however, a minimum of 135 m / h is reached in the second minute.

As can be seen, temperature fluctuations in

upper intermediate column decreased from six to two degrees. At the same time, the fluctuation of the boiling point of the first side stream decreases from 10 to 5 ° C.

Under conditions of normal maintenance of the regime of the temperature of the end of boiling light, oil products should be reduced by 15%.

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Claims (1)

Invention Formula The method of controlling the process of primary processing of oil in a complex distillation column with deaf plates, including the regulation of water vapor in the lower sections of simple columns, the regulation of the flow rate of each simple column depending on the temperature of the upper sections of simple columns, characterized in that the accuracy of temperature control of boil-out of petroleum products; in addition, they measure the flow rates of the circulation irrigation of each simple column and the flow rate schuschey simple column is adjusted with the correction of the flow rate of the circulating reflux simple each subsequent column. 63 59 2 // 7 / s 71