CN215288650U

CN215288650U - Fractionating system

Info

Publication number: CN215288650U
Application number: CN202121044618.XU
Authority: CN
Inventors: 刘哲; 王鑫; 昝大鑫; 邓宏达; 吕云飞
Original assignee: Zhangjiagang Free Trade Zone Huixin Chemical Technology Co ltd
Current assignee: Zhangjiagang Free Trade Zone Huixin Chemical Technology Co ltd
Priority date: 2021-05-17
Filing date: 2021-05-17
Publication date: 2021-12-24
Anticipated expiration: 2031-05-17

Abstract

The application discloses a fractionation system relates to the petrochemical field. The fractionation system comprises: a fractionating column; the first stripping tower is connected with an upper tray of the fractionating tower through a pipeline seven, the kerosene product is extracted from the upper tray of the fractionating tower, and the first stripping tower is used for stripping light fractions from the kerosene product; and the second stripping tower is connected with the lower tray of the fractionating tower through a pipe twelve and a pipe thirteen, the diesel oil product is extracted from the lower tray of the fractionating tower, and the second stripping tower is used for stripping light fraction from the diesel oil product. This application is through separating the product strip bottom product, when obtaining qualified naphtha, kerosene and diesel oil product, through the reasonable total energy consumption that has reduced the system of heat integration, the maximize has solved the bottleneck with the past technique, for the long period operation of system provides the assurance, more can adapt to the market demand.

Description

Fractionating system

Technical Field

The application relates to the technical field of petrochemical industry, in particular to a fractionation system.

Background

The suspension bed hydrocracking technology is a thermal hydrocracking process, and can convert petroleum residue and coarse coal into marketable liquid fraction. The suspension bed reactor adopts slurry feeding, namely oil-solid mixed feeding. The oil phase is heavy oil to be processed, such as vacuum residuum, coal tar, catalytic slurry oil, asphalt and the like, and the solid phase is added catalyst, additive or coal powder.

In addition, another fixed bed reactor system can be matched at the downstream of the suspension bed reactor system, and gasoline and diesel oil products with high economy can be obtained through re-hydrofining and hydrocracking of the suspension bed reactor products, so that the total product yield is increased, and the operation flexibility of the whole device is greatly improved.

The fractionating tower is a downstream device of a product stripping tower in the suspension bed hydrocracking device, and the fractionating tower is mainly used for separating naphtha products, kerosene products, diesel oil products and wax oil products from products at the bottom of the product stripping tower. In the prior art, the fractionating tower is used as a separation tower for obtaining a final product, the quality of the obtained product is difficult to reach the standard, and the heat efficiency of the whole tower is low.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a fractionation system, solve among the prior art fractionation product quality and be difficult to reach standard and the problem that whole tower thermal efficiency is low.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions: a fractionation system, comprising: a fractionating column; the first feeding pipe is directly communicated with the middle part of the fractionating tower and is used for conveying gas from an upstream flash tank; a heating furnace is arranged between the feeding pipe II and the fractionating tower, and liquid from an upstream pre-flash tank is firstly sent into the heating furnace for preheating and then sent into the middle lower part of the fractionating tower through a pipeline I; the first stripping tower is connected with an upper tray of the fractionating tower through a pipeline seven, the kerosene product is extracted from the upper tray of the fractionating tower, and the first stripping tower is used for stripping light fractions from the kerosene product; and the second stripping tower is connected with the lower tray of the fractionating tower through a pipe twelve and a pipe thirteen, the diesel oil product is extracted from the lower tray of the fractionating tower, and the second stripping tower is used for stripping light fraction from the diesel oil product.

In above-mentioned technical scheme, this application embodiment separates through stripping bottom product to the product, when obtaining qualified naphtha, kerosene and diesel oil product, through the reasonable overall energy consumption that has reduced the system of heat integration, the maximize has solved the bottleneck of the past technique, provides the assurance for the long period operation of system, more can adapt to market demand.

Further, according to the embodiment of the present application, wherein, at the bottom of the heating furnace, a gas pipe is provided, that is, the heating furnace obtains heat by burning fuel gas.

Further, according to the embodiment of the application, a second pipeline is arranged at the bottom of the fractionating tower, and the second pipeline is used for conveying medium-pressure steam to the bottom of the fractionating tower.

Further, according to the embodiment of the application, the gas phase product at the top of the fractionating tower is discharged through the third pipeline, the third pipeline is provided with a condenser, the condenser is used for supercooling, and the condensed liquid enters the reflux tank.

Further, according to the embodiment of the present application, an equilibrium line is further disposed between the third pipe and the reflux tank, and the equilibrium line bypasses the condenser to send part of the gas from the top of the fractionating tower into the reflux tank.

Further, according to the embodiment of the present application, the oil phase product in the reflux tank is divided into two streams after being pressurized by the reflux pump: one is taken as naphtha product through a pipeline six and is sent to a downstream debutanizer under the control of flow control and liquid level cascade; the other strand of the mixed gas flows back to the fractionating tower through a return pipe, the return flow is controlled by a flow controller, and the flow controller is controlled by the cascade of the tower top temperature of the fractionating tower.

Further, according to the embodiment of the present application, the bottom tray liquid of the first stripping tower is sent to the first reboiler through a pipe ten and then returned to the bottom sump in the first tower, and the first reboiler uses the product at the bottom of the fractionating tower as a heating medium.

Further, according to the embodiment of the present application, the overhead gas of the first stripping tower is returned to the fractionating tower, and the kerosene product at the bottom of the first stripping tower is sent out through the conduit nine.

Further, according to the embodiment of the present application, the bottom tray liquid of the second stripping tower is sent to the second reboiler through the pipe seventeen and then returned to the bottom sump in the second stripping tower, and the second reboiler uses the bottom product of the fractionating tower as a heating medium.

Further, according to the embodiment of the application, the overhead gas of the second stripping tower is returned to the fractional distillation.

Compared with the prior art, the method has the following beneficial effects: this application is through separating the product strip bottom product, when obtaining qualified naphtha, kerosene and diesel oil product, through the reasonable total energy consumption that has reduced the system of heat integration, the maximize has solved the bottleneck with the past technique, for the long period operation of system provides the assurance, more can adapt to the market demand.

Drawings

The present application is further described below with reference to the drawings and examples.

FIG. 1 is a schematic diagram of a fractionation system of the present application.

In the attached drawings

1. Fractionating tower 2, feeding pipe I3 and feeding pipe II

4. Heating furnace 5, pipeline one 6 and gas pipe

7. Pipeline two 8, pipeline three 9, condenser

10. A return tank 11, a return pipe 12 and a pipeline IV

13. Pipeline five 14, pipeline six 15, balanced pipeline

16. A seventh pipeline 17, a first stripping tower 18 and an eighth pipeline

19. Nine 20 pipelines, ten 21 pipelines and a reboiler I

22. Eleven 23, twelve 24 and thirteen pipelines

25. Fourteen 26 pipelines, two 27 stripping towers and fifteen pipelines

28. Reboiler II 29, pipeline sixteen 30, pipeline seventeen

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clear and fully described, embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of some embodiments of the invention and are not limiting of the invention, and that all other embodiments obtained by those of ordinary skill in the art without the exercise of inventive faculty are within the scope of the invention.

In the description of the present invention, it should be noted that the terms "center", "middle", "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", "side", "vertical", "horizontal", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "a," "an," "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

For the purposes of simplicity and explanation, the principles of the embodiments are described by referring mainly to examples. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that the embodiments may be practiced without these specific details. In some instances, well-known methods and structures have not been described in detail so as not to unnecessarily obscure the embodiments. In addition, all embodiments may be used in combination with each other.

The present application shows a schematic diagram of a fractionation system by means of fig. 1. As shown in fig. 1, the fractionation system includes a fractionation column 1, a first feed line 2, and a second feed line 3. Wherein the feed pipe 2 is directly connected to the middle part of the fractionating tower 1 for conveying gas from an upstream flash drum (not shown in the figure). A heating furnace 4 is arranged between the feeding pipe II 3 and the fractionating tower 1, and liquid from an upstream pre-flash tank is firstly fed into the heating furnace 4 for preheating and then fed into the middle lower part of the fractionating tower 1 through a pipeline I5. The design size of the heating furnace 4 can be reduced by allowing the flash tank to feed gas and liquid separately. At heating furnace 4 bottom, be provided with gas pipe 6, heating furnace 4 obtains the heat through burning fuel gas promptly, and the valve on the gas pipe 6 is controlled by the flow calculator, and two way signals are received to this controller: one path is a pressure signal behind a fuel gas valve and a flow signal of fuel gas, and the flow signal is also cascade-controlled by the outlet temperature of the heating furnace 4. And a second pipeline 7 is arranged at the bottom of the fractionating tower 1, and the second pipeline 7 is used for conveying medium-pressure steam to the bottom of the fractionating tower 1.

In addition, the gas-phase product at the top of the fractionating tower 1 is discharged through a third pipeline 8, a condenser 9 is arranged on the third pipeline 8, the gas-phase product is subcooled through the condenser 9, and the condensed liquid enters a reflux tank 10, so that the fractionating system in the embodiment has no gas-phase product under normal conditions. Further, the pressure of the fractionation system in this embodiment is controlled by two pressure controllers: the pressure at the top of the fractionating tower 1 is regulated by a pressure control valve on a third pipeline 8; the pressure in the reflux drum 10 is maintained by a separate pressure controller on line four 12, line four 12 being the gas phase outlet line of the reflux drum 10.

In addition, an equilibrium line 15 is provided between line three 8 and reflux drum 10, which bypasses condenser 9 to feed a portion of the gas from the top of fractionation column 1 to reflux drum 10, thereby allowing fractionation column 1 and reflux drum 10 to operate at the same pressure. Specifically, if the pressure in the reflux drum 10 is too high due to too much non-condensable gas in the reflux drum, gas is released from the reflux drum 10 and sent to a flare; if the reflux drum 10 pressure is too low, the overhead control valve will close, thereby allowing the pressure to rise.

The water condensed from the steam is collected in a reflux tank 10 and sent by a pipe five 13 to a downstream wash water tank (not shown in the drawing) for recovery under liquid level control. The oil phase product in the reflux tank 10 is divided into two streams after being pressurized by the reflux pump: one is sent to a downstream debutanizer (not shown in the figure) as naphtha product under flow control and liquid level cascade control through a line six 14; the other strand of the mixed gas flows back to the fractionating tower 1 through a return pipe 11, the return flow rate is controlled by a flow controller, and the flow controller is controlled by the cascade of the tower top temperature of the fractionating tower 1. If the overhead temperature is too high, the amount of reflux increases. If the temperature is too low, the amount of reflux decreases. The overhead temperature determines the end point of the naphtha product, and if the naphtha end point is too high, the overhead temperature set point needs to be lowered, whereas if the naphtha end point is too low, the overhead temperature set point can be raised.

The fractionation system further comprises a first stripping column 17, wherein the first stripping column 17 is used for stripping light fractions from the kerosene product. The first stripping tower 17 is connected with a certain tray at the upper part of the fractionating tower 1 through a pipeline seven 16, and the product kerosene is extracted. The liquid level in the first stripping column 17 is maintained by a liquid level flow control valve on the cascade control line seven 16.

The bottoms tray liquid of stripper one 17 is sent to reboiler one 21 via line ten 20 and then returned to the bottoms sump in the column. The reboiler one 21 uses the product at the bottom of the fractionating tower 1 as a heating medium, and the product at the bottom of the fractionating tower 1 is conveyed through a pipe fifteen 27 and a pipe sixteen 29, and the pipe sixteen 29 is communicated with a pipe eleven 22. The eleventh pipe 22 has one end passing through the reboiler one 21 and the other end bypassing the reboiler one 21. The difference between the reboiler one 21 return temperature and the stripper one 17 feed temperature is arranged to regulate the flow of the fractionation column bottoms stream into and around the reboiler to regulate the reboiler duty. Sixteen pipes 26 are fitted with booster valves through which the feed to the reboiler increases the pressure drop and thus allows the bypass to function properly. If the light ends of the kerosene product are too high and therefore do not meet the flash point requirement, the reboiler reflux temperature set point can be increased to remove more light ends. The gas at the top of the first stripping tower 17 returns to a tray above a kerosene extraction tray of the fractionating tower 1, the kerosene product at the bottom of the first stripping tower 17 is sent out through a pipeline nine 19, a kerosene product pump is arranged on the pipeline nine 19 and used for pressurizing, the gas is sent to an air cooler or/and a water cooler (not shown in the drawing) under the flow control to be cooled to a proper temperature, and finally the gas is sent to a boundary area to be collected as the kerosene product.

The fractionation system further includes a second stripper column 26, where the second stripper column 26 is used to strip light ends from the diesel product. Stripper column two 26 draws diesel from a tray below the fractionator via line twelve 23 and line thirteen 24.

The bottom tray liquid of stripper two 26 is sent to reboiler two 28 via line seventeen 30 and then returned to the bottom sump in the column. The reboiler two 28 uses the bottom product of the fractionating tower 1 as a heating medium, the bottom product of the fractionating tower 1 is sent out through a pipeline fifteen 27, and the pipeline fifteen 27 and a pipeline sixteen 29 are respectively connected with two ends of the tube pass of the reboiler two 28. The temperature difference between the reboiler ii 28 return temperature and the stripper column feed temperature is used to regulate the flow of the bottoms stream of the fractionation column 1 into and around the reboiler ii 28, thereby regulating the reboiler duty. Line fifteen 27 is fitted with a pressure increase valve through which the feed to the reboiler increases the pressure drop and thus allows the bypass to function properly. If the light ends of the diesel product are excessive, the reflux temperature set point of reboiler two 28 may be increased to remove more light ends. And the tower top gas of the second stripping tower 26 returns to a tray above a diesel oil extraction tray of the fractionating tower 1, the diesel oil product at the tower bottom is pressurized by a diesel oil product pump, and is sent to other downstream heat exchangers (not shown in the figure) under the flow control to recover heat, and finally is sent to a battery compartment to be collected as a diesel oil product.

In addition, the fractionating tower 1 is provided with a fourteen 25 line, and the fourteen 25 line is a diesel oil circulation side stream for removing heat from the tower to reduce the amount of gas at the top of the tower, and the fourteen 25 line is also used as a reflux in the middle of the fractionating tower 1. The recycle diesel is pumped out on the same tray as the feed to the second stripper 28, is pumped to a recycle diesel steam generator by a diesel recycle pump of the fractionating tower under cascade control of flow control and temperature, removes heat by vaporizing boiler feed water into medium pressure steam, and returns to the tray above the draw-out tray. The liquid level in the recycle diesel steam generator is maintained by adjusting the boiler feed water feed rate via a liquid level control valve.

Finally, a fractionating system described in this embodiment separates through product strip bottom product, when obtaining qualified naphtha, kerosene and diesel oil product, through the reasonable total energy consumption that has reduced the system of heat integration, the maximize has solved the bottleneck of the past technique, provides the assurance for the long period operation of system, more can adapt to market demand.

Although the illustrative embodiments of the present application have been described above to enable those skilled in the art to understand the present application, the present application is not limited to the scope of the embodiments, and various modifications within the spirit and scope of the present application defined and determined by the appended claims will be apparent to those skilled in the art from this disclosure.

Claims

1. A fractionation system, comprising:

a fractionating column;

a first feed line communicating directly with the middle of the fractionation column for conveying gas from an upstream flash drum;

a heating furnace is arranged between the feeding pipe II and the fractionating tower, and liquid from an upstream pre-flash tank is firstly sent into the heating furnace for preheating and then sent into the middle lower part of the fractionating tower through a pipeline I;

the first stripping tower is connected with the upper tray of the fractionating tower through a pipeline seven, kerosene products are extracted from the upper tray of the fractionating tower, and the first stripping tower is used for stripping light fractions from the kerosene products;

and the second stripping tower is connected with the lower tray of the fractionating tower through a pipe twelve and a pipe thirteen, the diesel oil product is extracted from the lower tray of the fractionating tower, and the second stripping tower is used for stripping light fractions from the diesel oil product.

2. A fractionation system according to claim 1, wherein a gas pipe is provided at a bottom of the heating furnace, i.e., the heating furnace obtains heat by burning fuel gas.

3. The fractionation system of claim 1, wherein a second conduit is disposed at the bottom of the fractionation column for delivering medium pressure steam to the bottom of the fractionation column.

4. A fractionation system according to claim 1, wherein the gas phase product at the top of the fractionation column is discharged through a third pipeline, a condenser is disposed on the third pipeline, the condenser is used for supercooling, and the condensed liquid enters a reflux drum.

5. A fractionation system according to claim 4, further comprising an equalization line between conduit three and the reflux drum, the equalization line bypassing the condenser and passing a portion of the gas from the top of the fractionation column to the reflux drum.

6. A fractionation system according to claim 4, wherein the oil phase product in the reflux tank is divided into two streams after being pressurized by the reflux pump: one is taken as naphtha product through a pipeline six and is sent to a downstream debutanizer under the control of flow control and liquid level cascade; and the other strand of the mixed gas flows back to the fractionating tower through a return pipe, the return flow is controlled by a flow controller, and the flow controller is controlled by the cascade of the tower top temperature of the fractionating tower.

7. A fractionation system according to claim 1, wherein the bottoms tray liquid of the first stripper is sent through line ten to a first reboiler and then returned to the bottom sump in the first stripper, the first reboiler using the product from the bottom of the fractionation column as a heating medium.

8. A fractionation system according to claim 1, wherein the overhead gas from the first stripper is returned to the fractionation column and the kerosene product from the bottom of the first stripper is sent via conduit nine.

9. A fractionation system according to claim 1, wherein the bottom tray liquid of the second stripper is fed through conduit seventeen to a second reboiler and then returned to the bottom sump in the second stripper, the second reboiler using the bottoms of the fractionation column as a heating medium.

10. A fractionation system according to claim 1, wherein overhead gas from said second stripper is returned to fractionation.