JPS5855002A - Controlling method for reflux liquid of distillation device - Google Patents

Abstract

PURPOSE:To increase the production of intended components without any trouble by reintroducing a part of the components which are produced additionally and are drawn in an atmospheric distillation tower into a distillation tower, extracting reflux liquid from the part in the upper stage of the distillation tower, and radiating heat therefrom then reintroducing the same into the distillation tower. CONSTITUTION:When the intermediate fraction, for example, gas oil, in the stage of distilling ulticomponent hydrocarbons is produced additionally, the gas oil discharged through a gas oil discharge pipe 41 is subjected to heat exchanging with the waste gas discharged through a gas discharge pipe 42 from a heating furnace 27 by a heat exchanger 43, and is heated to above its b.p., then the gas oil is reintroduced into the part of an atmospheric distillation tower 28 where the temp. is equal approximately to the heating temp. Further the reflux liquid in the tower 28 is discharged through a reflux liquid pipe 44 and is subjected to heat exchanging with crude oil in a heat exchanger 45 then the liquid is introduced again into the tower 28. As a result, the reflux liquid in the gas oil fractional distillation part in the tower 28 is increased. Therefore, the degree of rectification of the gas oil is improved and the production of the gas oil is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting a reflux liquid in a distillation apparatus, and more particularly to a method for adjusting a reflux liquid for increasing the volume of intermediate distillate when distilling multi-component hydrocarbons.

Conventionally, for example, crude oil was converted into gasoline, kerosene, and light oil.

When heavy gas oil and heavy oil components are distilled and fractionated, this is carried out based on a 70-sheet diagram of a crude oil atmospheric distillation apparatus shown in FIG.

To briefly describe the distillation fractionation system using this equipment fK, crude oil supplied from a crude oil supply pipe 1 is sequentially preheated by each heat exchanger 2 to 6, and then introduced into a heating furnace T, where gasoline, kerosene, The gas oil and heavy gas oil components are vaporized, heated to a temperature at which the heavy oil components (hereinafter referred to as atmospheric residual oil) are in a liquid state, and introduced into the atmospheric dropless column 8 . In the atmospheric pressureless dropless column B, the vaporized components move upward, and during this movement, the HWC is classified in descending order of boiling point, that is, heavy gas oil, gas oil, kerosene, and gasoline.
The M distillate is separated into a heavy gas oil collection pipe 9 and a gas oil collection pipe 10 from a predetermined location, respectively. It is discharged from the kerosene sampling pipe 11 and the gasoline sampling pipe 12. Note that only gasoline is discharged as a gas from the top of the atmospheric pressureless dropless tower 8, and is discharged from the gasoline collection pipe 12 via a gas-liquid separator 13.

On the other hand, while the liquid atmospheric residual oil is led to the bottom of the atmospheric pressureless dropless column 8, the light components contained therein are vaporized and separated (stripped) by the steam from the steam pipe 14.
The residual oil is discharged from the atmospheric pressure residual oil sampling pipe 15. Each component extracted from the atmospheric pressure dropless column 8 is sent to a tank that does not contain
Alternatively, it is sent to the next purification step. Note that 16 is a gasoline reflux liquid pipe.

In this crude oil atmospheric distillation equipment, since the content of each component varies depending on the type of crude oil, the operating conditions of the atmospheric distillation equipment are determined according to the type of crude oil, and each component is separated according to the content ratio. However, it is not always theoretically perfect; for example, if the boiling point of diesel oil is close to that of heavy diesel oil, it will be mixed with heavy diesel oil, and conversely if the boiling point of heavy diesel oil is close to that of diesel oil, it will be mixed with heavy diesel oil. is mixed with light oil. Other ingredients are similar to Kameoka.

By the way, in recent years, among the various components of ti crude oil, kerosene in particular.

Demand for light oil is increasing, and it is desired to increase production by distilling and fractionating it as completely as possible.

Therefore, in the past, when increasing the production of light oil, for example, the valve 17 of the light oil sampling pipe 10 of the atmospheric pressure dropless tower 8 was opened wider than usual to increase the amount of light oil extracted. In this case, as the amount of light oil extracted increases, the internal reflux liquid of the non-droplet portion of heavy light oil in the normal pressure non-droplet column 8 decreases, and from this point of view, the mixing of heavy light oil into the light oil becomes more intense. Put it away. For this reason, a method has been used to increase the temperature at the outlet of the heating furnace 7 into which the crude oil is introduced, thereby increasing the heat supply into the dropless column 8 and increasing the internal reflux liquid. It is unfortunate that this method cannot be said to be advantageous from the viewpoint of thermal economy, but there is also the problem of increased decomposition of petroleum products due to high-temperature heating.

The present invention was developed in view of the above-mentioned circumstances, and is made by heating a part of the component to be produced, which is collected in an atmospheric pressure dropless tower, to a temperature higher than the boiling point of the component using the heat source of the dropless device. When the reflux liquid is reintroduced into the atmospheric dropless column, the reflux liquid is extracted from the atmospheric pressureless column section above the sampling stage of the relevant component, and is then reintroduced into the atmospheric pressureless column after being allowed to radiate heat. The purpose of this method is to increase the reflux liquid in the non-droplet area of the component to be produced, thereby increasing the production of the target component without any hindrance.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a 74-sheet diagram of a crude oil atmospheric distillation apparatus to which the first embodiment of the present invention is applied. In Fig. 2, petroleum crude oil is supplied from a crude oil supply pipe 21 to a gasoline vapor extraction pipe 2, which will be described later.
, the xau oil collector 937 and the atmospheric residual oil collection pipe 4T, and are sequentially preheated by the heat exchangers 22 to 26, respectively, and then introduced into the heating furnace 2T. Here, the IJK oil is heated at a temperature at which each component of gasoline, kerosene, light oil, and heavy light oil is vaporized and the heavy oil component (normal pressure residual oil) becomes a water-liquid state, and then introduced into the normal pressure dropless column 28. be done. In the atmospheric pressureless dropless column 28, the atmospheric residual oil is led to the bottom, while the vaporized components move upwards.During this movement, they are cooled by the reflux liquid and are separated in the order of their boiling points: heavy gas oil, gas oil, kerosene. It is distilled and fractionated in the following order: Ganlin. Among these, kerosene.

Light oil 1 Heavy light oil is in liquid state and each sampling pipe is 35.36°37
When extracted from the oil and flowing through each collection pipe 35, 38, 37, it exchanges heat with the crude oil in the aforementioned heat exchangers 23, 24, 25, and is further cooled to an appropriate temperature in each cooler 3B, 39°40. is discharged. Only gasoline is extracted in a gaseous state from the top of the atmospheric pressureless dropless column 2B through a small gasoline vapor extraction tube 29, and is heat exchanged with crude oil in an interposed heat exchanger 22.
After further cooling in the cooler 30, the I/c% gas-liquid separator 3
1 will be introduced. As a result, the gas and the gasoline reservoir are separated, and the gasoline reservoir is discharged from the gasoline collection pipe 34, but a part of the fuel, that is, the amount necessary for dropless separation, is constantly pumped through the gasoline reflux liquid pipe 33. It is refluxed to the pressureless dropless column 28. on the other hand,
The gas is discharged from the gas vent pipe 32.

The process of collecting each component of the kernels is the same as the conventional one, but in the present invention, when increasing the production of components such as light oil as in this embodiment, the light oil in the atmospheric pressureless dropless column 28 as shown in FIG. A light oil extraction pipe 41 is provided to extract a part of the gas oil to the outside of the tower 280. After undergoing heat exchange and heating above its boiling point, it is reintroduced into the atmospheric pressure dropless column 28, which is approximately equal to the heating temperature. In addition, the amount of light oil to be extracted is set so that the reflux ratio after production increase (the amount of reflux liquid in the light oil extraction stage relative to the amount of light oil extracted) is the same as or greater than the reflux ratio before production increase6.
In addition to the above-mentioned operation, a reflux liquid pipe 44 for extracting the reflux liquid is provided at a position above the light oil collection pipe 36 of the normal pressure dropless column 2-8, and the OR flow liquid in the normal pressure dropless column 28 is converted into the reflux liquid. The crude oil is taken out from the pipe 44, inserted into the crude oil supply pipe 21, cooled by exchanging heat with the crude oil in the heat exchanger 45, and then introduced into the normal pressure dropless column 28 again.

Due to the busyness of these operations, it is possible to increase the reflux liquid in the light oil fractionating non-droplet section in the atmospheric pressure dropless column 28.

Therefore, it is possible to improve the degree of refinement of light oil and increase the production of light oil. However, since the waste heat in the Kame system is used, the energy saving effect is large. .

On the other hand, when the atmospheric residual oil is led to the bottom of the atmospheric pressureless dropless column 28, a small amount of light components contained therein are vaporized and separated by the steam from the steam pipe 46 when being led to the bottom. It is then extracted from the atmospheric residual oil sampling pipe 47, cooled appropriately through the heat exchanger 26 and the cooler 48, and then discharged. The discharged components were as shown in the figure, for example, when Arabian crude oil was processed at 25,200 barrels/day (4,006 KL/El).

Conventionally, the light oil content was 17.8 inches of crude oil, or 4,490 barrels/day (29.7 KL411p), and the running power ζ At this time, the internal reflux ratio of the light oil extraction stage was 4.04. .

In this example, we will obtain reinforcements for light oil, one portion of which will be 25.6KL/
Assume that the time is heat exchanged with the heating furnace exhaust gas (398℃), 2
Since it was heated to 73℃, it was transferred to the heavy gas oil extraction stage (2
92°C).

As a result, the amount of heat input at the bottom of the light oil painting stage was 1.32.
Increased by 2,000 Kcal/II@, which makes the internal reflux ratio of the light oil test stage (assuming the same amount of light oil extracted) 5.0.
It was increased to 6.

Therefore, even if 151 (4.5 KL/hour) of diesel oil is added, the internal reflux ratio will only decrease to 4.4, compared to the conventional 4.
Compared to 04, there was more margin at the end, so the degree of distillation of light oil was good.

On the other hand, the internal reflux liquid also increases due to the above-mentioned increase in the amount of heat input above the light oil extraction stage, but in this embodiment, the amount of heat this has is 2.
After heating the crude oil, the internal reflux liquid (42 KL/H) extracted at 43°C was returned to the tower under the kerosene extraction stage at 185°C.

As a result, the internal return **a of the kerosene extraction stage was reduced to the same level as before.

FIG. 4 shows a second embodiment of the invention.

The difference between this embodiment and the first embodiment is that after being extracted from the atmospheric pressure dropless column 28 and heated, the dropless column 2BVC is heated again.
As a heating source for the introduced light oil, the thermal energy possessed by the atmospheric residual oil extracted at high temperature from the bottom of the atmospheric pressure MII tower 28 is used instead of the exhaust gas from the heating furnace 27.

That is, the light oil extraction pipe 5 is branched from the light oil sampling pipe 36.
1, and the extraction pipe 51 is connected to the atmospheric residual oil sampling pipe 47#.
C to a predetermined position in the atmospheric pressureless dropless column 28 via the heat exchanger 52! Continue. In this configuration, a part of the extracted light oil is passed through the light oil extraction pipe 51 to the heat exchanger 5''.
2, where it exchanges heat with the atmospheric residual oil from the atmospheric dropless column 28 and is heated above the boiling point. Introduce. Note that the other operations are the same as those in the first embodiment, and the explanation will be omitted.

In this embodiment, as in the first embodiment, the amount of busy reflux liquid increases, and the production of light oil can be increased without any problems, and the energy saving effect is large.

Further, FIG. 5 shows a third embodiment.

In this embodiment, before introducing preheated crude oil into the heating furnace 21, it is introduced into a seven-lush tank 55, and light gasoline is evaporated in a fuel tank. 28 directly through a pipe 56, while the cut crude oil from which light gasoline has been separated from the lower part of the flash tank 55 is introduced into the heating furnace 21, heated, and then transferred to the atmospheric pressure dropless column 28.
We are trying to introduce it to Then, a part of the heavy gas oil is mixed with the crude oil before being introduced into the heating furnace 2T via the heavy gas oil extraction pipe 51 which is provided by branching off from the heavy gas oil collection pipe 37, and is heated together with the crude oil in the heating furnace 2T. Then, it is reintroduced into the atmospheric pressure dropless column 28.

The rest is the same as the other embodiments, and the explanation will be omitted.

In this case as well, the same effect as in each of the above-mentioned embodiments is obtained.
In the first and second embodiments, the case of light oil was described, but the same applies to the case of kerosene, and in this case, the reflux liquid is drawn out of the dropless column from the upper end of the kerosene sampling pipe. t, 3rd
In the embodiment, only heavy gas oil is mixed into the crude oil, but it is also possible to mix kerosene, gas oil, heavy gas oil, or a mixture thereof. Furthermore, the present invention is applicable not only to crude oil but also to multi-component hydrocarbons similar to #C, such as fluid catalytic cracked oil, heavy hydrotreated refined oil, heavy hydrocracked oil, etc. It is possible.

As explained above, according to the present invention, a part of the components to be produced that are tested in the atmospheric pressure dropless column is reheated using an existing heat source or waste heat, and then reintroduced into the dropless column. At the same time, the reflux liquid is extracted from the non-droplet column section above the sampling stage for this component and is introduced into the dropless column again after being radiated.
Therefore, the energy-saving broom key effect is large, and the reflux liquid can be increased without any trouble, and the production of the target ingredient can be increased.

[Brief explanation of drawings]

FIG. 1 is a flow sheet diagram of a conventional crude oil atmospheric distillation apparatus, FIG. 2 is a 70-sheet diagram of a crude oil atmospheric distillation apparatus to which an embodiment of the reflux liquid adjustment method according to the present invention is applied, and FIG. 1st
70-sheet diagram showing a specific example of the embodiment, FIG. 4 and ta
s diagram is a flow sheet diagram of a crude oil atmospheric distillation apparatus to which different embodiments are applied. 21... Crude oil supply pipe 27-... Heating furnace 28-
・Normal pressure dropless tower 36...Light oil collection pipe 41.51
... Light oil extraction pipe 42 ... Gas discharge pipe 4
3゜45.53--Heat exchanger 44-Reflux liquid pipe 47-Normal pressure residual oil collection pipe Patent applicant Fujio Sasashima, representative patent attorney for Nippon Oil Co., Ltd. Figure 1

Claims (3)

[Claims] (1) An oil liquid containing multiple components with different boiling points is heated in a heating furnace and then introduced into an atmospheric distillation tower, and the components vaporized by the heating are brought into contact with the reflux liquid as they rise through the atmospheric distillation tower. In a distillation apparatus that separates each component by distillation and collects each component from each sampling stage provided in the distillation column, a selected part of each component to be collected is collected. After reheating the components to a temperature higher than their boiling point, the components are reintroduced into the atmospheric distillation tower section that is approximately equal to the heating temperature, and the reflux liquid is extracted from the atmospheric distillation tower section above the selective component collection stage, and the oil liquid is A method for adjusting a reflux liquid in a distillation apparatus, characterized in that the reflux liquid in the distillation section of the selected component is increased by K when the selected component is reintroduced into the atmospheric distillation column after being used as a preheating source. (2) The selected component is reheated using the heat of exhaust gas from a heating furnace that heats the oil liquid.
A method for adjusting a reflux liquid in a distillation apparatus as described in 1. (3) Selected components are reheated by extraction from the bottom of the atmospheric distillation tower.