Sequential separation system of ethylene device

Abstract

The utility model relates to the technical field of petrochemical engineering, and discloses a sequential separation system of an ethylene device, which comprises a first subsystem, a second subsystem and a second subsystem, the first subsystem comprises a dethanizing column, a first cooling unit, a first reboiler and a first input pipe, the first input pipe is configured to input propylene into the dethanizing column, the first cooling unit is circularly communicated with the top of the dethanizing column, and the first reboiler is communicated with the top of the dethanizing column; the first reboiler is arranged in the deethanizer and configured to input ethylene into the deethanizer, and the first reboiler is circularly communicated with the bottom of the deethanizer; the second subsystem comprises a depropanizing tower, a second cooling unit, a second reboiler and a second input pipe, the second input pipe is configured to input liquefied petroleum gas into the depropanizing tower, the second cooling unit is in circulating communication with the top of the depropanizing tower and configured to input propylene into the depropanizing tower, and the second reboiler is in circulating communication with the bottom of the depropanizing tower. According to the utility model, the deethanization tower and the depropanization tower can carry out total reflux operation in advance, and the adjustment time of driving is shortened.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of petroleum chemical industry, in particular to a kind of ethylene plant sequential separation system. BACKGROUND

[0002] Ethylene plant is with petroleum or natural gas as raw material, with high-purity ethylene and propylene production as main, while by-product multiple petroleum chemical raw material petroleum chemical plant.In the sequential separation process of ethylene plant, in addition to ethylene rectification column and propylene rectification column can lead ethylene and propylene to carry out full reflux operation, realize the purpose of reverse start-up.Deethanizer, depropanizer and debutanizer are more difficult to carry out full reflux operation, so that adjustment time is longer, affect production efficiency. SUMMARY

[0003] The utility model aims at providing a kind of ethylene plant sequential separation system, can make deethanizer and depropanizer carry out full reflux operation in advance, shorten the adjustment time of start-up.

[0004] To achieve the above object, the utility model provides a kind of ethylene plant sequential separation system, comprising:

[0005] First subsystem, including deethanizer, first cooling unit, first reboiler and first input pipe, the first input pipe is configured to input propylene to the deethanizer, the first cooling unit is cyclically communicated with the top of the deethanizer, and is configured to input ethylene to the deethanizer, and the first reboiler is cyclically communicated with the bottom of the deethanizer;And

[0006] Second subsystem, including depropanizer, second cooling unit, second reboiler and second input pipe, the second input pipe is configured to input liquefied petroleum gas to the depropanizer, the second cooling unit is cyclically communicated with the top of the depropanizer, and is configured to input propylene to the depropanizer, and the second reboiler is cyclically communicated with the bottom of the depropanizer;

[0007] Wherein, the outlet of the deethanizer is communicated with the inlet of the depropanizer.

[0008] In some embodiments, first cooling unit includes first cooler, first reflux tank and first reflux pump, and the deethanizer, the first cooler, the first reflux tank and the first reflux pump are sequentially cyclically communicated.

[0009] In some embodiments, first regulating valve is installed at the inlet of the first reflux tank, and the first regulating valve is used to adjust the pressure and flow of ethylene input into the first reflux tank.

[0010] In some embodiments, the first subsystem further comprises a first condensate pump in communication with the first reboiler and configured to remove condensate from the first reboiler.

[0011] In some embodiments, a first liquid supplement valve is installed on the first input pipe.

[0012] In some embodiments, the second cooling unit comprises a second cooler, a second reflux tank and a second reflux pump, and the depropanizer, the second cooler, the second reflux tank and the second reflux pump are sequentially and circularly communicated.

[0013] In some embodiments, a second regulating valve is installed at the inlet of the second reflux tank and configured to regulate the pressure and flow rate of the propylene input into the second reflux tank.

[0014] In some embodiments, the second subsystem further comprises a second condensate pump in communication with the second reboiler and configured to remove condensate from the second reboiler.

[0015] In some embodiments, a second liquid supplement valve is installed on the second input pipe.

[0016] In some embodiments, a third regulating valve is installed at the outlet of the depropanizer and configured to communicate the outlet of the depropanizer with the inlet of the debutanizer.

[0017] The utility model provides a kind of ethylene device sequential separation system, compared with prior art, its beneficial effect lies in:

[0018] The first input pipe is configured to input propylene into the deethanizer, the first cooling unit is circularly communicated with the top of the deethanizer, and is configured to input ethylene into the deethanizer, by optimizing the ratio of ethylene and propylene in the deethanizer, the deethanizer is operated in full reflux in advance;The second input pipe is configured to input liquefied petroleum gas into the depropanizer, the second cooling unit is circularly communicated with the top of the depropanizer, and is configured to input propylene into the depropanizer, by optimizing the ratio of propylene and liquefied petroleum gas, the depropanizer is operated in full reflux in advance, so as to shorten the adjustment time of starting. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The first subsystem principle schematic diagram of the ethylene device sequential separation system provided by the utility model embodiment.

[0020] Figure 2 The second subsystem principle schematic diagram of the ethylene device sequential separation system provided by the utility model embodiment.

[0021] In the figure: 100, first subsystem; 1, de-ethanizer; 2, first cooling unit; 21, first cooler; 22, first reflux tank; 23, first reflux pump; 24, first regulating valve; 3, first reboiler; 31, first condensate pump; 4, first input pipe; 41, first liquid supplement valve; 200, second subsystem; 5, de-propanizer; 51, third regulating valve; 6, second cooling unit; 61, second cooler; 62, second reflux tank; 63, second reflux pump; 64, second regulating valve; 7, second reboiler; 71, second condensate pump; 8, second input pipe; 81, second liquid supplement valve. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0023] It should be understood that, in the description of the present application, the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated must be provided with a particular orientation, constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. The terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. That is, the features with "first" and "second" can explicitly or implicitly include one or more of the features. In addition, unless otherwise stated, the meaning of "multiple" is two or more.

[0024] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0025] As Figures 1-2 shown, the ethylene device sequential separation system of the embodiment of the present application includes a first subsystem 100 and a second subsystem 200. In use, the first subsystem 100 is used to separate ethane from crude oil or natural gas. The second subsystem 200 is used to separate propane from crude oil or natural gas.

[0026] The first subsystem 100 comprises a deethanizer 1, a first cooling unit 2, a first reboiler 3 and a first input pipe 4 configured to input propylene into the deethanizer 1, the first cooling unit 2 is in circulation communication with the top of the deethanizer 1 and configured to input ethylene into the deethanizer 1, wherein the ethylene in the first cooling unit 2 is provided by a tank area system. The first reboiler 3 is in circulation communication with the bottom of the deethanizer 1. When the first subsystem 100 is in operation, it is confirmed that the nitrogen replacement in the deethanizer 1 is qualified (the condition is that the oxygen content is <0.2%), the gas phase ethylene is introduced into the deethanizer 1 through the first cooling unit 2 to pressurize to 0.55-0.7 MPa, 3 t / h of liquid phase propylene is input into the deethanizer 1 through the first input pipe 4, and then the gas phase ethylene is introduced into the deethanizer 1 through the first cooling unit 2 to pressurize to 1.5 MPa.

[0027] The second subsystem 200 comprises a depropanizer 5, a second cooling unit 6, a second reboiler 7 and a second input pipe 8 configured to input liquefied petroleum gas into the depropanizer 5, the second cooling unit 6 is in circulation communication with the top of the depropanizer 5 and configured to input propylene into the depropanizer 5, wherein the propylene in the second cooling unit 6 is provided by a tank area system. The second reboiler 7 is in circulation communication with the bottom of the depropanizer 5. When the second subsystem is in operation, it is confirmed that the nitrogen replacement in the depropanizer 5 is qualified (the condition is that the oxygen content is <0.2%). 5 t / h of liquefied petroleum gas is input into the depropanizer 5 through the second input pipe 8, the outlet of the depropanizer 5 is opened to charge liquid into the depropanizer 5, and when the liquid level of the depropanizer 5 is reduced to 80%, the outlet of the depropanizer 5 is closed.

[0028] In the embodiment, the outlet of the deethanizer 1 is in communication with the inlet of the depropanizer 5.

[0029] Based on the above settings, the first input pipe 4 is configured to input propylene into the deethanizer 1, the first cooling unit 2 is in circulation communication with the top of the deethanizer 1 and configured to input ethylene into the deethanizer 1, by optimizing the ratio of ethylene and propylene in the deethanizer 1, the deethanizer 1 is operated in full reflux; the second input pipe 8 is configured to input liquefied petroleum gas into the depropanizer 5, the second cooling unit 6 is in circulation communication with the top of the depropanizer 5 and configured to input propylene into the depropanizer 5, by optimizing the ratio of liquefied petroleum gas and propylene in the depropanizer 5, the depropanizer 5 is operated in full reflux in advance, thereby shortening the adjustment time of starting.

[0030] As Figure 1As shown, in one embodiment, the first cooling unit 2 includes a first cooler 21, a first reflux tank 22, and a first reflux pump 23. The deethanizer 1, the first cooler 21, the first reflux tank 22, and the first reflux pump 23 are sequentially connected in a circulating manner. During operation, the tank area system inputs 6t of liquid ethylene into the first reflux tank 22 to establish the liquid level of the first reflux tank 22. When the liquid level reaches 30%, the first reflux pump 23 is started and adjusted to the minimum flow line to stabilize the liquid level of the first reflux tank 22. After the first cooler 21 precools the top of the deethanizer 1 for 10 minutes, the first reboiler 3 is turned on to establish full reflux operation. The ratio of ethylene to propylene in the deethanizer 1 is adjusted to 2:1, which can meet the full reflux operation conditions of the deethanizer 1.

[0031] In one embodiment, a first regulating valve 24 is installed at the inlet of the first reflux tank 22. The first regulating valve 24 is used to regulate the pressure and flow rate of ethylene input into the first reflux tank 22.

[0032] In one embodiment, the first subsystem 100 further includes a first condensate pump 31, which is connected to the first reboiler 3 and is used to discharge condensate from the first reboiler 3. Additionally, steam is introduced into the inlet of the first reboiler 3 for heating.

[0033] In one embodiment, a first replenishment valve 41 is installed on the first input pipe 4. This valve is used to regulate the input flow rate of propylene in the first input pipe 4.

[0034] like Figure 2 As shown, the second cooling unit 6 includes a second cooler 61, a second reflux tank 62, and a second reflux pump 63. The propane stripper 5, the second cooler 61, the second reflux tank 62, and the second reflux pump 63 are sequentially and cyclically connected. During operation, the tank farm system pressurizes the second reflux tank 62 to 0.6 MPa, turns on the second cooler 61, switches the tank farm system to a liquid phase propylene flow, introduces 3 t / h of liquid phase propylene, establishes the liquid level in the second reflux tank 62, and when the liquid level reaches 50%, the second reflux pump 63 is started to adjust the minimum flow line to stabilize the liquid level in the second reflux pump 63. The second reboiler 7 is then turned on to establish full reflux operation. Once a stable full reflux state is reached, the supply of liquid phase propylene is stopped.

[0035] In one embodiment, a second regulating valve 64 is installed at the inlet of the second reflux tank 62, which is used to regulate the pressure and flow rate of propylene entering the second reflux tank 62.

[0036] In one embodiment, the second subsystem 200 further includes a second condensate pump 71, which is connected to the second reboiler 7 and is used to discharge condensate from the second reboiler 7. Additionally, steam is introduced into the inlet of the second reboiler 7 for heating.

[0037] In one embodiment, a second liquid supplement valve 81 is installed on the second input pipe 8. The second liquid supplement valve 81 is used to adjust the flow size of the liquefied petroleum gas in the second input pipe 8.

[0038] In one embodiment, a third regulating valve 51 is installed at the outlet of the depropanizer 5, and the outlet of the depropanizer 5 is communicated with the inlet of the debutanizer through the third regulating valve 51. The third regulating valve 51 is beneficial to the sequential separation production operation.

[0039] The above description is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and substitutions can be made, and these improvements and substitutions should also be considered as the protection scope of the present application.

Claims

1. A sequential separation system for an ethylene plant, characterized in that, include: A first subsystem includes a deethanizer, a first cooling unit, a first reboiler, and a first inlet pipe. The first inlet pipe is configured to feed propylene into the deethanizer. The first cooling unit is in circulation communication with the top of the deethanizer and is configured to feed ethylene into the deethanizer. The first reboiler is in circulation communication with the bottom of the deethanizer. The second subsystem includes a propane dehydrogenator, a second cooling unit, a second reboiler, and a second inlet pipe. The second inlet pipe is configured to supply liquefied petroleum gas to the propane dehydrogenator. The second cooling unit is in circulation communication with the top of the propane dehydrogenator and is configured to supply propylene to the propane dehydrogenator. The second reboiler is in circulation communication with the bottom of the propane dehydrogenator. The outlet of the ethane stripper is connected to the inlet of the propane stripper.

2. The sequential separation system for an ethylene plant according to claim 1, characterized in that, The first cooling unit includes a first cooler, a first reflux tank, and a first reflux pump, wherein the deethaner, the first cooler, the first reflux tank, and the first reflux pump are sequentially and cyclically connected.

3. The sequential separation system for an ethylene plant according to claim 2, characterized in that, A first regulating valve is installed at the inlet of the first reflux tank. The first regulating valve is used to regulate the pressure and flow rate of ethylene input into the first reflux tank.

4. The sequential separation system for an ethylene plant according to claim 1, characterized in that, The first subsystem further includes a first condensate pump, which is connected to the first reboiler and is used to discharge condensate from the first reboiler.

5. The sequential separation system for an ethylene plant according to claim 1, characterized in that, A first replenishment valve is installed on the first input pipe.

6. The sequential separation system for an ethylene plant according to claim 1, characterized in that, The second cooling unit includes a second cooler, a second reflux tank, and a second reflux pump, and the propane dehydrogenator, the second cooler, the second reflux tank, and the second reflux pump are sequentially and cyclically connected.

7. The sequential separation system for an ethylene plant according to claim 6, characterized in that, A second regulating valve is installed at the inlet of the second reflux tank. The second regulating valve is used to regulate the pressure and flow rate of propylene input into the second reflux tank.

8. The sequential separation system for an ethylene plant according to claim 1, characterized in that, The second subsystem also includes a second condensate pump, which is connected to the second reboiler and is used to discharge condensate from the second reboiler.

9. The sequential separation system for an ethylene plant according to claim 1, characterized in that, A second replenishment valve is installed on the second input pipe.

10. The sequential separation system for an ethylene plant according to claim 1, characterized in that, The outlet of the propane stripper is equipped with a third regulating valve, and the outlet of the propane stripper is connected to the inlet of the butane stripper through the third regulating valve.

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