JPH08157835A - Feeding of crude oil to atmospheric distillation apparatus and apparatus used therefor - Google Patents

Abstract

PURPOSE: To provide a method for feeding crude oil to an atmospheric distillation apparatus, capable of preventing large change in operation state of atmospheric distillation apparatus accompanied by changeover of a crude oil tank or lowering in yield of fraction having high value added caused by the change, and stably, safely and economically carrying out operation of the atmospheric distillation apparatus and provide an apparatus therefor. CONSTITUTION: Plural crude oil feeding series 13 and 14 for feeding crude oil to an atmospheric pressure distillation apparatus 1 are provided and each of these crude oil feeding series 13 and 14 is selectively connected to either of plural crude oil tanks 11 and 12 and flow rates of crude oil feeding series 13 and 14 is respectively controlled by flow rate controlling means 28 and 29 and crude oils of crude oil tanks 11 and 12 are mixed at a desired ratio and the mixed crude oil is fed to the atmospheric pressure distillation apparatus 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for supplying crude oil to an atmospheric distillation unit in petroleum refining, and can be used when mixing crude oil in a plurality of crude oil tanks and supplying the mixture to the atmospheric distillation unit. .

[0002]

2. Description of the Related Art Generally, in a refinery, various crude oils are first fractionated by an atmospheric distillation unit into several types of fractions, and each of these fractions is processed by a secondary unit such as a desulfurization unit. I have. At this time, if the remaining amount of crude oil in the crude oil tank that supplies crude oil to the atmospheric distillation apparatus at a certain point in time has decreased, the atmospheric pressure distillation apparatus or the like is continuously switched to another crude oil tank. Are driving. By the way, when the crude oil tank is switched and crude oil different from the crude oil that has been supplied is supplied to the atmospheric distillation unit, the yield and properties of each fraction in the atmospheric distillation unit change, and the atmospheric distillation unit Changes in operating conditions, such as impairing the stability and safety of device operation,
The yield of high value-added fraction (white oil) decreases. Conventionally,
In order to prevent such a decrease in the yield of high value-added fractions and to ensure the stability and safety of the operation of the apparatus, blending of crude oil using a crude oil tank and stabilization control of the atmospheric distillation apparatus are performed. .

FIG. 8 shows a conventional crude oil supply device 90 for blending crude oil using a crude oil tank. The crude oil supply device 90 is a device that supplies crude oil to the atmospheric distillation device 99 arranged on the right side in the drawing, and includes a crude oil tank 91 that stores A crude oil, a crude oil tank 92 that stores B crude oil,
One crude oil supply line 93 connected to each of these crude oil tanks 91 and 92 and supplying crude oil to the atmospheric distillation unit 99 is provided. Note that the two crude oil tanks 91 and 92 are selected by switching from a large number of installed crude oil tanks. The crude oil supply line 93 is branched into three branch passages 93A, 93B, and 93C, and each of these branch passages 93A, 93B, and 93C has a pump 94.
A, 94B, 94C and flow control valves 95A, 95B, 9
5C is provided. Normally, each pump 94A-94
Two of C are operated, and the other is used as a backup in case of failure. In addition, electric open / close valves 96A and 96B are provided in portions of the crude oil supply system 93 connected to the respective crude oil tanks 91 and 92.

In such a conventional crude oil supply device 90, both the on-off valves 96A and 96B are opened, the A crude oil and the B crude oil in the crude oil tanks 91 and 92 are mixed, and the mixed crude oil is adjusted to each flow rate. While adjusting the flow rate with the valves 95A to 95C, the atmospheric distillation unit 9 is operated by the pumps 94A to 94C.
Send to 9. At this time, the amount of crude oil in each crude oil tank 91, 92 basically decreases evenly although there is a slight difference depending on the density of each crude oil. Conventionally, as a crude oil blending index when performing such crude oil blending, AP
I specific gravity (specific gravity display method established by the American Petroleum Institute) has been used.

[0005]

However, in the above-described crude oil blending method using the conventional crude oil supply device 90 shown in FIG. 8, in order to make the remaining amounts of the respective crude oil tanks 91 and 92 coincide, the crude oil shift operation (the crude oil tank 91) is performed. , 92 are connected by a line provided separately from the crude oil supply system 93), which is troublesome. In addition, the total number of crude oil tanks is fixed, and as the capacity of crude oil tankers and the processing capacity of crude oil increase, the tankers must be received with the remaining amount of crude oil being small. It is not possible to secure a sufficient time until the start of the supply to the crude oil, and after taking a time for removing impurities such as moisture in the crude oil, the crude oil must be immediately sent to the atmospheric distillation unit 99. For this reason, since the crude oil in the crude oil tank selected after switching cannot be made to have a desired property, there is a problem that the crude oils in the crude oil tanks 91 and 92 cannot be sufficiently blended. On the other hand, increasing the total number of crude oil tanks to address such problems is enormous and expensive.

Further, if the properties of the crude oil to be supplied are largely different without sufficiently blending the crude oil in each of the crude oil tanks 91 and 92, the operation state of the apparatus is greatly different, and the stability of the atmospheric distillation apparatus 99 is stabilized. There is a problem that computerization control cannot respond. Further, the API specific gravity conventionally used as a blending index of crude oil has a weak correlation with the yield of each fraction, and it has been difficult to prepare a crude oil supply step for an atmospheric distillation apparatus having stable properties.

SUMMARY OF THE INVENTION An object of the present invention is to prevent a large change in the operating state of the atmospheric distillation apparatus due to the switching of the crude oil tank and a decrease in the yield of high value-added fractions due to the change, thereby achieving stable and stable operation.
It is an object of the present invention to provide a method for supplying crude oil to an atmospheric distillation apparatus that can realize safe and economical operation of the atmospheric distillation apparatus, and an apparatus therefor.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to achieve the above object by providing a plurality of crude oil supply lines whose flow rates can be individually adjusted. Specifically, the method for supplying crude oil to the atmospheric distillation apparatus of the present invention is provided with a plurality of crude oil supply series for supplying crude oil from the crude oil tank to the atmospheric distillation apparatus, and each of these crude oil supply series is provided with a plurality of crude oil supply series. The crude oil is selectively connected to any of the provided crude oil tanks, the flow rate of each of these crude oil supply lines is adjusted to mix the crude oils of the selected crude oil tanks at a desired ratio, and the mixture is mixed. The crude oil is supplied to the atmospheric distillation apparatus. Here, the above ratio is a flash /
It is desirable to adjust the inclination of the reference line (FRL) as an index.

Further, the crude oil supply apparatus for the atmospheric distillation apparatus of the present invention is provided with a plurality of crude oil tanks, each of which is selectively connected to any one of the crude oil tanks. A plurality of crude oil supply lines for supplying crude oil to the pressure distillation apparatus, and flow rate adjusting means provided in each of these crude oil supply lines are provided. Here, the flow rate adjusting means may be manually operated so as to obtain a desired flow rate ratio, but a control means for operating each flow rate adjusting means to adjust the flow rate ratio of each crude oil supply series is provided. It is desirable to keep. And the control means is a flash reference indicating the distillation property of crude oil.
It is desirable to adjust the flow rate ratio using the inclination of the line (FRL) as an index to mix the crude oil in each crude oil tank.

[0010]

In the present invention as described above, a plurality of crude oil supply lines for supplying crude oil from the crude oil tank to the atmospheric distillation unit are provided, and the flow rates of these crude oil supply lines are individually adjusted. The flow rate ratio of the supply line can be adjusted freely, and the crude oil in each crude oil tank connected to each crude oil supply line is mixed at a desired ratio and sent to the atmospheric distillation unit. Therefore, even if a different crude oil from the crude oil that has been supplied until now is supplied from each crude oil tank with the switching of the crude oil tank, the normal pressure distillation can be performed by adjusting the flow rate ratio. Crude oil of a desired property can be supplied to the apparatus. Therefore, as compared with the case where the crude oil supply system 93 like the conventional crude oil supply apparatus 90 of FIG. 8 described above performs the blending of the crude oil, the property of the crude oil supplied to the atmospheric distillation apparatus can be stabilized. The change in the operating state of the atmospheric distillation unit due to the switching of the crude oil tank is suppressed,
As well as improving the yield of high value-added fractions,
Safe and economical operation of the atmospheric distillation unit is realized,
By these, the above-mentioned object is achieved.

Further, when the control means for operating the flow rate adjusting means to adjust the flow rate ratio of each crude oil supply system is provided, the setting and adjustment to an appropriate flow rate ratio can be performed quickly and surely, and the normal pressure can be adjusted. It is possible to further stabilize the operation state of the distillation apparatus and improve the yield of the high value-added fraction. In addition to setting and adjusting the flow rate ratio, this control means also makes it possible to easily maintain the required amount (absolute amount) of crude oil supply to the atmospheric distillation apparatus before and after switching of the crude oil tank.

Further, when the flow rate ratio is adjusted by using the slope of the FRL indicating the distillation property of crude oil as an index to mix the crude oil in each crude oil tank, compared with the conventional API specific gravity as an index, Since the correlation with the yield of each fraction is strong, it becomes possible to create a crude oil supply step to an atmospheric distillation apparatus that can supply crude oil with more stable properties.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a crude oil supply device 10 to an atmospheric distillation apparatus of the present embodiment. Crude oil supply device 10
Is a device for supplying crude oil to the atmospheric distillation device 1 arranged on the right side in the figure, and a crude oil tank 11 for storing A crude oil;
A crude oil tank 12 for storing B crude oil, two crude oil supply systems 13 and 14 connected to the crude oil tanks 11 and 12 to supply the crude oil to the atmospheric distillation apparatus 1, and the crude oil supply systems 13 and 14, respectively. Control means 30 for controlling flow rate as a whole
And a computer 31 for calculating control information used by the control means 30. In addition, two crude oil tanks 1
Reference numerals 1 and 12 denote the currently selected crude oil tank by switching from a large number of installed crude oil tanks, and the remaining crude oil tanks are omitted from the description.

Each of the crude oil supply lines 13 and 14 can be connected to each of the crude oil tanks 11 and 12, and a portion of one of the crude oil supply lines 13 connected to each of the crude oil tanks 11 and 12 is electrically operated. On-off valves 21A and 21B are provided, and the crude oil tanks 11 and 12 of the other crude oil supply system 14 are provided.
The electric on-off valve 21
C and 21D are provided. These four on-off valves 2
1A to 21D are operated when switching the crude oil tanks, and when connecting the crude oil tanks 11 and 12 to the crude oil supply systems 13 and 14, respectively, the open / close valves 21A and 21D are opened. Open / close valves 21B and 21C
Is closed and the crude oil tanks 11 and 12 are connected to the crude oil supply lines 14 and 13, respectively, the on-off valves 21A and 21D are closed and the on-off valves 21B and 21C are closed.
Is opened.

One crude oil supply line 13 is branched into two branch passages 22A and 22B, and each of these branch passages 22A and 22B.
22B includes electric suction side valves 23A and 23B, respectively.
B, pumps 24A and 24B, first flow control valve 25
A and 25B are provided. In addition, each pump 24
Second flow control valves 27A and 27B are provided in minimum flow lines 26A and 26B for securing the minimum flow rate arranged so as to connect the front and rear of A and 24B, respectively. These suction side valves 23A, 23B, pump 24
A, 24B, the first flow rate control valves 25A, 25B, and the second flow rate control valves 27A, 27B are used to control the crude oil supply line 13.
The flow rate adjusting means 28 for adjusting the flow rate of the above is constituted.

Similarly, the other crude oil supply line 14 is branched into two branch passages 22C and 22D. Each of the branch passages 22C and 22D has an electric suction side valve 23 respectively.
C, 23D, pumps 24C, 24D, first flow control valves 25C, 25D are provided, and minimum flow lines 26C, 26D are provided with second flow control valves 27C, 27D. These suction side valves 23C, 23D,
Pumps 24C, 24D, first flow rate control valves 25C, 25
D and the second flow control valves 27C and 27D constitute a flow control means 29 for controlling the flow of the crude oil supply system 14.

The control means 30 controls a supply system flow rate ratio control S
1, a pump minimum flow securing control S2, a control S3 based on a pump start / stop determination sequence, and a control S4 based on a modularized sequence of pump start / stop operations.

In the feed series flow rate ratio control S1, in order to adjust the flow rate ratio of each crude oil supply series 13 and 14 while maintaining the required amount (absolute amount) of crude oil supply to the atmospheric distillation apparatus 1, each of the absolute amounts is adjusted. Crude oil supply series 13 and 14 (each branch path 22A to 2)
Multiplied by the flow ratio setting value of each 2D
It is calculated as a set value of the flow rates of A to 22D (the flow rates passing through the first flow rate control valves 25A to 25D). That is, for each input of the absolute amount and the flow rate setting value,
The flow set value of 22D is output. As an example of setting the flow ratio, for example, when the flow ratio of each of the branch passages 22A to 22D is 50%, 30%, 20%, and 0%, respectively, the flow ratio of each of the crude oil supply systems 13 and 14 Are 80% and 20% respectively, and crude oil A and crude oil B are 8:
Mixed at 2. The flow rate set value used in the control S1 is calculated by the computer 31 every time the crude oil tank is switched, and is sent to the control means 30 online or offline.

The pump minimum flow securing control S2 is performed similarly for each of the pumps 24A to 24D (each of the branch passages 22A to 22D). Here, the pump 24A will be described. In this control S2, the flow rate Q flowing through the pump 24A
The second flow rate control valve 27A or the second flow rate control valve 27A or the first flow rate control valve 25A or the second flow rate control valve 27A or the second flow rate control valve 27A so that the total flow rate of the flow rate Q2 and the second flow rate control valve 27A does not fall below a preset pump minimum flow rate setting value. One flow rate adjusting valve 25A is adjusted.
That is, in response to the input of the minimum pump flow rate setting value, the flow rate setting value of each of the minimum flow lines 26A to 26D (the passing flow rate setting value of each of the second flow rate control valves 27A to 27D) is output.

In the control S3 based on the pump start / stop determination sequence, each of the crude oil supply systems 13 and 14 (each branch 22
A to 22D) for each pump 24A to 24D.
Output a start / stop command. That is, each branch road 22A-
A pump start / stop command is output in response to the input of the actual flow rate of 22D. In addition, a method is used in which a reference value for judging pump start and a reference value for judging pump stop are set to different values (method of providing a so-called dead zone) so as not to repeat judgment of starting and stopping due to small fluctuations in the flow rate. .

The control S4 based on a modularized sequence of pump start / stop operations is performed by the pumps 24A to 24D.
, But the pump 24A will be described here. In this control S4, the pump 24A, the first flow control valve 25A, the second flow control valve 27A, and the suction side valve 23A are adjusted according to the pump start / stop procedure, and the start / stop of the pump 24A is automatically performed. That is, the pump start / stop signal and the valve opening / closing signal are output in response to the input of the pump start / stop command. In the control S4, for example, control is performed according to the following procedures. The passage flow rate Q1 of the first flow rate control valve 25A decreases due to the setting by the supply series flow rate ratio control S1. When the flow rate Q1 becomes equal to or less than the pump minimum flow rate set value, the pump minimum flow rate securing control S2 sets the flow rate Q2 of the minimum flow line 26A. (A) Flow rate Q1 is zero, (b) First flow control valve 25A
(C) the pump start / stop determination sequence is in operation, (d) the crude oil supply system 13
The required flow rate is within the capacity of the other pump 24B,
(E) A of (a) to (f) that the target value of the flow rate Q1 is equal to or less than a predetermined value, and (f) the flow rate Q2 is equal to or more than a predetermined value.
When the ND condition is satisfied, the pump 24A is stopped. The suction side valve 23A is closed.

Each time the crude oil tank is switched, the computer 31 calculates the TBP of the crude oils A and B in the crude oil tanks 11 and 12.
(True boiling point) The distillation curve was synthesized at the ratio of the crude oil mixture ratio to form a single distillation curve and its FR
L (flash reference line) slope is obtained, and the obtained FRL slope falls within an appropriate range, that is, the FRL before and after the switching of the crude oil tank.
The crude oil mixing ratio is adjusted so that the difference between the slopes of the crude oil falls within the range in which the quality loss does not occur, and the flow rate set value of each crude oil supply series 13, 14 is determined.

FIG. 2 is an explanatory diagram of a method for synthesizing a distillation curve of mixed crude oil performed by the computer 31. Figure 2
When the TBP distillation curves of crude oils A and B shown in the upper left and upper right of the middle are mixed at a mixing ratio of 7: 3, for example,
As shown in the lower part of FIG. 2, the TBP distillation curves of the crude oil A and the crude oil B are scaled down to 70% and 30% according to the respective mixing ratios, and the TBP distillation curve of the crude oil B (dotted line in the figure) is translated. After that, the TBP distillation curve of crude oil B was
Add to the P distillation curve to create a single synthesized distillation curve.

FIG. 3 is an explanatory diagram of a method of calculating the inclination of FRL. The FRL is a straight line showing what percentage of the original capacity of petroleum or the like should be evaporated at one atmospheric pressure, and the slope of the FRL is the slope of the straight line. First, as shown in FIG. 3, a DRL (distortion reference
The slope of (line) is calculated by the following formula. DRL slope = (T70-T10) / (70-10)
[° F /%] Next, the slope of the FRL is obtained using a chart (commonly used in the field of petroleum refining) showing the relationship between the slope of the DRL and the slope of the FRL.

In this embodiment, crude oil is supplied to the atmospheric distillation apparatus 1 as follows. First, each of the crude oil tanks 11 and 12 is operated by operating the on-off valves 21A to 21D.
Is connected to either of the crude oil supply lines 13 and 14. Each of the crude oil tanks 11 and 12 is a crude oil tank to be used for supplying crude oil. Further, based on the TBP distillation curves of the crude oils A and B in each of the crude oil tanks 11 and 12, a computer 31 is used.
Thus, the mixing ratio of A crude oil and B crude oil is set to an appropriate value using the slope of FRL as an index, and the flow rate ratio of each crude oil supply series 13, 14 is determined.

Next, based on the calculation result by the computer 31, the control means 30 operates the respective flow rate adjusting means 28, 29 to adjust the flow rate of each of the crude oil supply systems 13, 14, and to determine the flow rate ratio of these and the sum of them. Control is performed so that the flow rate becomes a desired value. Then, A crude oil and B crude oil are mixed at a desired ratio, and the mixed crude oil is sent to the atmospheric distillation apparatus 1.

According to this embodiment, the following effects can be obtained. That is, a plurality of crude oil supply lines 13 and 14
And the flow rates of these crude oil supply lines 13 and 14 are individually adjusted.
The crude oils A and B in the crude oil tanks 11 and 12 can be mixed at a desired ratio by adjusting the flow rate ratio of the crude oil tanks 11 and 12 and sent to the atmospheric distillation apparatus 1. Therefore, since the crude oil having the desired properties can be supplied to the atmospheric distillation device 1, the above-mentioned FIG.
As compared with the case where the crude oil is blended by one crude oil supply line 93 like the conventional crude oil supply device 90, the properties of the crude oil supplied to the atmospheric distillation device 1 can be stabilized. Then, by stabilizing the property of the supplied crude oil, it is possible to suppress the change in the operating state of the atmospheric distillation apparatus 1 due to the switching of the crude oil tank, and it is possible to improve the yield of the high value-added fraction and to stabilize the It is possible to realize a safe and economical operation of the atmospheric distillation apparatus 1.

Further, since the control means 30 is provided, the flow rate ratio of each of the crude oil supply lines 13 and 14 can be set and adjusted quickly and reliably, and the operation state of the atmospheric distillation apparatus 1 can be stabilized and improved. The yield of high value added fractions can be further improved. Furthermore, the control unit 30 can easily maintain the absolute amount of crude oil supplied to the atmospheric distillation apparatus 1, in addition to adjusting the setting of the flow rate ratio.

The flow rate ratio is adjusted by using the slope of the FRL as an index to mix the A crude oil and the B crude oil in the crude oil tanks 11 and 12, respectively. Since the correlation with the yield of the distillate is strong, crude oil can be supplied to the atmospheric distillation apparatus 1 with more stable properties.

In order to confirm the effect of the present invention, the following comparative experiment was conducted. FIG. 4 shows a specific example of an oil refining plant 50 equipped with a device similar to the crude oil supply device 10 of the above-described embodiment, while FIG. 5 includes a device similar to the conventional crude oil supply device 90. Oil refinery plant 80
Are shown. 4, a plant 50 to which the present invention is applied includes crude oil tanks 51A to 51P, of which a crude oil tank 51L indicated by a two-dot chain line in the figure.
５１51P are not involved in this comparative experiment because they are linked to another independent series. Remaining crude oil tank 5
1A to 51K are arranged so as to be connectable to the respective crude oil supply lines 53 and 54. Since each of the crude oil tanks 51A to 51K is connected in a loop, any one of the crude oil tanks is connected to the crude oil supply system 53 or the crude oil supply system 54 by operating a valve provided at each location. You may.

For example, the series switching line 55 disposed between the crude oil tanks 51D and 51E and the valves provided in the vicinity thereof are opened and closed to operate the respective crude oil tanks 51D and 51E.
The crude oil 1E is allowed to flow in the X and Y directions in the figure, respectively, and the crude oil tank 51E is
3 to connect the crude oil tank 51D to the other crude oil supply system 5
4 can be connected. From this state, the crude oil tank 5
The connection (flow in the X direction) between the 1D and the crude oil supply system 54 is kept as it is, and the crude oil tank 51E is
When switching to 1C, each valve of the line switching line 55 is operated to stop the flow in the Y direction from the crude oil tank 51E, and each of the line of the line switching line 56 arranged between the crude oil tanks 51B and 51C. The valve is operated so that the crude oil in the crude oil tank 51C flows in the Z direction indicated by the dashed line in the figure. Further, when the crude oil tank 51E is switched to the crude oil tank 51C, the flow can be gradually switched by appropriately operating the slightly openable valves provided in the series switching lines 55 and 56. There is.

In FIG. 5, a conventional plant 80 to which the present invention is not applied has crude oil tanks 81A to 81P, of which a crude oil tank 81L indicated by a two-dot chain line is shown.
Since ~ 81P is linked to another independent series, it does not participate in the present comparative experiment. Remaining crude oil tank 8
All of 1A to 81K are arranged in a loop so that they can be connected to one crude oil supply line 83. When the crude oil is supplied to the atmospheric distillation unit, two crude oil tanks among the crude oil tanks 81A to 81K are connected to the crude oil supply system 83 by operating valves provided in the respective parts to mix the crude oil. . Then, when there is no more crude oil in these two crude oil tanks, another crude oil tank is switched to.

[0033]

[Table 1]

Table 1 shows that the plant 80 before the present invention was implemented.
Each operation result of the atmospheric distillation apparatus in the plant (FIG. 5) and the plant 50 (FIG. 4) after the present invention is implemented is shown. Also,
FIG. 6 shows a change in the yield of each fraction of the atmospheric distillation apparatus of the plant 80 (FIG. 5) before the present invention is implemented, and FIG. 7 shows a normal state of the plant 50 (FIG. 4) after the present invention is implemented. The change in the yield of each fraction of the pressure distillation apparatus is shown. Here, the FRN writer is a name of a combination of full-range naphtha (FRN) and a fraction lighter than FRN, and includes a gas component, LPG, and FPG.
It means the sum of RN. KERO is unwashed kerosene, L
GO is light gas oil, HGO is heavy gas oil, and RC is normal pressure residual oil.

According to Table 1, the value of the standard deviation of each fraction change rate after carrying out the present invention is FR compared with the value before carrying out the present invention.
With the exception of the N lighter, the size was reduced, and it is shown that the yield of each fraction was stabilized by the present invention. 6 and 7
7 also shows that there is less change in FIG. 7 after implementing the present invention. According to Table 1, the yield of white oil (the sum of the yields of KERO and LGO), which is a high value-added fraction, is higher after the present invention than before the present invention. It is shown that the present invention has reduced the quality loss. The effects of the present invention were remarkably shown by the results of the above comparative experiments.

The present invention is not limited to the above-mentioned embodiments, and modifications and the like within the range in which the object of the present invention can be achieved are included in the present invention. That is, in the above embodiment, each of the flow rate adjusting means 28 and 29 is
A to 23D, pumps 24A to 24D, first flow control valve 2
5A to 25D and the configuration including the second flow control valves 27A to 27D, but the present invention is not limited to such a configuration. For example, the pumps 24A to 24D and the first flow control valves 25A to 25D Only the configuration may be adopted, that is, it is sufficient that the flow rates of the respective crude oil supply systems 13 and 14 can be individually adjusted. In the above-described embodiment, each of the crude oil supply lines 13 and 14 is provided with two pumps. However, one pump is provided for each crude oil supply line (however, one having sufficient capacity). May be provided, or three or more pumps may be provided.

Although the control means 30 is provided in the above embodiment, the flow rate adjusting means 28, 29 may be manually operated. However, it is preferable to provide the control means 30 in order to ensure and speedily adjust the flow rate. Further, in the above-described embodiment, the TBP distillation curves of A crude oil and B crude oil were synthesized by the calculator 31 to calculate the flow rate setting value, but such calculation may be performed manually. However, it is preferable that the calculation be performed by the computer 31 in order to ensure and speed up the calculation process.

In the above embodiment, the crude oil in the two crude oil tanks 11 and 12 is mixed by using the two crude oil supply lines 13 and 14. However, in the present invention, the crude oil tanks to be mixed are mixed. The number and the number of crude oil supply lines used for mixing are arbitrary as long as they are plural.

[0039]

As described above, according to the present invention, a plurality of crude oil supply lines are provided, and the flow rates of these crude oil supply lines are individually adjusted. By adjusting, the crude oil in each crude oil tank can be mixed at a desired ratio, so that the yield of high value-added fractions in the atmospheric distillation unit can be improved and stable, safe, and economical. There is an effect that the operation of the normal atmospheric distillation apparatus can be realized.

When control means for adjusting the flow rate ratio of each crude oil supply system by operating each flow rate adjusting means is provided, the setting and adjustment to an appropriate flow rate can be performed quickly and reliably. It is possible to further stabilize the operation state of the atmospheric distillation unit and improve the yield of high value-added fractions, and to supply the crude oil to the atmospheric distillation unit before and after switching the crude oil tank (absolute amount). Has the effect that it can be easily performed.

Furthermore, when the flow rate ratio is adjusted using the slope of the FRL indicating the distillation properties of crude oil as an index to mix the crude oil in each crude oil tank, compared with the conventional API specific gravity as an index, Since the correlation with the yield of each fraction is strong, there is an effect that the properties can be further stabilized and the crude oil can be supplied to the atmospheric distillation apparatus.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory view of a method for synthesizing a distillation curve of mixed crude oil in the above example.

FIG. 3 is an explanatory diagram of a method of calculating a slope of FRL in the embodiment.

FIG. 4 is a diagram illustrating a plant configuration after the present invention is used in a comparative experiment.

FIG. 5 is a configuration diagram of a plant before the present invention used in a comparative experiment.

FIG. 6 is a diagram showing a change in the yield of each fraction of the atmospheric distillation apparatus of the plant before the present invention, obtained in a comparative experiment.

FIG. 7 is a view showing a change in the yield of each fraction of the atmospheric distillation apparatus of the plant after the practice of the present invention, obtained in a comparative experiment.

FIG. 8 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Atmospheric distillation apparatus 10 Crude oil supply apparatus 11, 12, 51A-51K Crude oil tank 13, 14, 53, 54 Crude oil supply system 28, 29 Flow rate adjusting means 30 Control means

Claims (5)

[Claims] 1. A plurality of crude oil supply lines for supplying crude oil from a crude oil tank to an atmospheric distillation unit are provided, and each of these crude oil supply lines is selectively provided in any one of the crude oil tanks. Characterized in that the crude oil in each of the selected crude oil tanks is mixed at a desired ratio by adjusting the flow rate of each of these crude oil supply series, and the mixed crude oil is supplied to the atmospheric distillation apparatus. And a method for supplying crude oil to an atmospheric distillation apparatus. 2. The method for supplying crude oil to an atmospheric distillation apparatus according to claim 1, wherein the ratio is adjusted by using a slope of a flash reference line indicating a distillation property of crude oil as an index. Crude oil supply method to pressure distillation apparatus. 3. A plurality of crude oil tanks, and a plurality of crude oil supply systems selectively connected to any of these crude oil tanks to supply crude oil from the selected crude oil tanks to an atmospheric distillation apparatus. A crude oil supply apparatus for an atmospheric distillation apparatus, comprising: a flow rate adjusting means provided in each of these crude oil supply series. 4. The crude oil supply apparatus for an atmospheric distillation apparatus according to claim 3, further comprising control means for operating each of the flow rate adjusting means to adjust a flow rate ratio of each of the crude oil supply series. A crude oil supply device for an atmospheric distillation device. 5. The crude oil supply apparatus for an atmospheric distillation apparatus according to claim 3 or 4, wherein the control means comprises:
A crude oil supply apparatus for an atmospheric distillation apparatus, characterized in that the flow rate ratio is adjusted using the inclination of a flash reference line indicating the distillation property of crude oil as an index to mix the crude oil in each crude oil tank.