Rich liquor rectifying column for dehydration of triethylene glycol

Abstract

The utility model discloses a rich liquor rectifying column for dehydration of triethylene glycol, which relates to the technical field of dehydration of triethylene glycol and comprises a rectifying column body, a regenerated waste gas pipeline is connected inside the rectifying column body, the bottom end of the regenerated waste gas pipeline is connected with a steel plate, the middle of the steel plate is connected with a vertical steel pipe, and vertical through holes are arranged on the steel plate on the periphery of the vertical steel pipe. The vertical steel pipe is communicated with the regenerated waste gas pipeline and extends towards one side far away from the regenerated waste gas pipeline, one end, far away from the regenerated waste gas pipeline, of the vertical steel pipe is fixedly connected with an elbow steel pipe, the free end of the elbow steel pipe is fixedly connected with a horizontal steel pipe, and the free end of the horizontal steel pipe extends out of the rectifying column and is fixedly connected with a waste gas outer guide pipe; a top outlet of the rectifying column body is connected with a sealing structure. The loss of the triethylene glycol solution is reduced by the improved rectifying column, so that the effect of improving the economic benefit is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of triethylene glycol dehydration, in particular to a rich liquid distillation column for triethylene glycol dehydration. Background Art

[0002] Triethylene glycol (TEG) is a colorless, odorless, viscous liquid with strong hydrophilicity. It can be used as an absorbent to fully contact with natural gas and transfer water to the solvent to achieve the purpose of dehydration. TEG has a low vapor pressure and is easy to regenerate. It is currently the most commonly used absorbent in the natural gas industry.

[0003] Triethylene glycol dehydration belongs to the solvent absorption dehydration method, which uses natural gas (the main component is CH 4 ) and H 2 O removes water from natural gas by the difference in solubility in triethylene glycol. The process is a physical absorption process. In the triethylene glycol dehydration unit, one part of the equipment is used for dehydration, and the other part is used for triethylene glycol regeneration. The process flow is as follows:

[0004] The raw natural gas from the gathering and transportation well station enters the bottom of the dehydration absorption tower after filtration, separation, desulfurization and decarbonization. The absorption tower is a place where gas and liquid are transferred. The natural gas flows upward in the tower and fully contacts the triethylene glycol solution flowing downward on each layer of the tower plate. The natural gas after being dehydrated by triethylene glycol leaves the absorption tower and enters the sales pipeline or other terminals.

[0005] TEG enters from the top of the absorption tower as an absorbent, crosses the tower plate and flows to the bottom of the tower. After contacting with natural gas and absorbing water vapor, TEG is called rich glycol (rich liquid). After the rich glycol is depressurized from the bottom of the absorption tower, it is heat exchanged through the heat exchange coil at the top of the rich liquid distillation column of the reboiler, and then enters the flash tank to remove the contained gas and hydrocarbon liquid to reduce the load of the regeneration tower. After flowing out of the flash tank, TEG then enters the filter to remove impurities, and then enters the TEG lean-rich liquid heat exchanger for heat exchange, and then enters the buffer tank after heat exchange. The rich liquid first passes through the heat exchange coil in the buffer tank and then enters the bottom of the distillation column for concentration, and then enters the reboiler; in the reboiler, although the boiling points of water and TEG are different, a small amount of TEG will evaporate while evaporating water. After the rich liquid is heated to about 202°C in the reboiler, the water in the triethylene glycol is heated and vaporized. In order to speed up the discharge of water, natural gas is introduced as a stripping gas to carry out the vaporized water vapor, and at the same time, a small amount of triethylene glycol is entrained and discharged from the top of the distillation column. Triethylene glycol is distilled and purified in the reboiler to complete the regeneration, which is called lean glycol (lean liquid). The regenerated lean glycol flows into the buffer tank, and re-enters the top of the absorption tower after being pressurized by the circulating pump to start a new dehydration process. The regenerated gas generated by the regeneration of the TEG rich liquid is separated by the TEG regeneration gas separator, and then enters the incinerator of the tail gas treatment device for incineration and is discharged into the atmosphere.

[0006] The regeneration tower of triethylene glycol has a combined structure. The regeneration tower is mainly composed of a distillation column, a reboiler and a buffer tank with a heat exchange coil. Its function is to evaporate the water in the glycol rich liquid to regenerate glycol for recycling. The distillation column is installed on the upper part of the reboiler. The filling in the column is usually 1.2 to 2.4 meters, and a tower plate can also be used. A cooling coil is provided at the top of the distillation column as a reflux condenser to condense part of the water vapor to provide reflux at the top of the column to control the temperature at the top of the column and reduce the loss of TEG. The reboiler mainly provides heat to heat the glycol to a certain temperature, so that the absorbed water is vaporized and discharged from the top of the distillation column, that is, the regeneration of the triethylene glycol solution. In addition, the reboiler also provides reflux vaporization heat load and supplements the heat dissipation loss. The reboiler is generally a kettle type, which can be directly heated by fuel gas, or heated by water vapor or heat transfer oil or other methods such as electric heating. The direct-fired reboiler, which usually uses an open flame heating tube, is in the shape of a U-shaped tube. The main function of the buffer tank is to hold all the glycol coming out of the absorption tower. During normal operation, the buffer tank should be half full, and an air seal should be set to prevent glycol from contacting the air.

[0007] Schematic diagram of the distillation column structure of the dehydration device Figure 1 As shown in the figure, the dehydration device has a high temperature of regeneration waste gas (98-100°C), which leads to a significant loss of triethylene glycol solution in the regeneration waste gas, that is, a higher temperature at the top of the distillation column will increase the loss of triethylene glycol. When the temperature exceeds 121°C, triethylene glycol will evaporate significantly. When the temperature at the top of the distillation column is approximately 107°C, the sampling and analysis of the discharge of the regeneration waste gas separator tank found that the proportion of triethylene glycol was about 50%, and the current unit price of triethylene glycol is 15,000 yuan / ton, so it will cause direct and serious economic losses. Utility Model Content

[0008] The technical problem to be solved by the utility model is that in the existing triethylene glycol dehydration device, due to the high temperature of the regenerated waste gas (98-100°C), the high top temperature of the distillation column will cause triethylene glycol to evaporate significantly, resulting in the regenerated waste gas carrying obvious triethylene glycol solution, the loss of triethylene glycol solution is large, and direct serious economic losses occur. Based on this, a rich liquid distillation column for triethylene glycol dehydration is proposed. The improved distillation column will reduce the loss of triethylene glycol solution, thereby achieving the effect of improving economic benefits.

[0009] The utility model is realized by the following technical solutions:

[0010] The present application provides a rich liquid distillation column for dehydration of triethylene glycol, comprising a distillation column body, wherein a regeneration waste gas pipeline is connected to the inside of the distillation column body, a steel plate is connected to the bottom end of the regeneration waste gas pipeline, and a vertical steel pipe is connected to the middle of the steel plate; the vertical steel pipe is communicated with the regeneration waste gas pipeline and extends to a side away from the regeneration waste gas pipeline, an end of the vertical steel pipe away from the regeneration waste gas pipeline is fixedly connected to an elbow steel pipe, a free end of the elbow steel pipe is fixedly connected to a horizontal steel pipe, the free end of the horizontal steel pipe extends to the outside of the distillation column and is fixedly connected to an exhaust gas outer conduit; a sealing structure is connected to the top outlet of the distillation column body.

[0011] Furthermore, a liquid blocking cylinder is arranged on the steel plate located at one side of the regeneration waste gas pipeline, the upper end of the liquid blocking cylinder is communicated with the regeneration waste gas pipeline, and the lower end of the liquid blocking cylinder is communicated with the vertical steel pipe.

[0012] Furthermore, the lower part of the liquid-blocking cylinder is a cylindrical cofferdam, and the upper part is a conical roof. The upper and lower parts of the liquid-blocking cylinder are connected by a support column; the regenerated exhaust gas enters the vertical steel pipe between the upper roof and the cylindrical cofferdam; the height of the cylindrical cofferdam is 15 to 30 mm.

[0013] The lower part of the liquid blocking cylinder is a cylindrical cofferdam, and the upper part is a conical roof. The upper and lower parts are connected by a support column, and the regeneration waste gas enters the vertical steel pipe from the upper roof and the lower cylinder. The lower cylindrical cofferdam has a certain height (15-30mm) to prevent the condensate on the steel plate from going over the cylindrical cofferdam and entering the vertical steel pipe. The function of the roof is that when the liquid droplets in the regeneration waste gas pipeline fall on the roof, the liquid droplets flow back to the steel plate along the edge of the roof to prevent it from entering the vertical steel pipe.

[0014] Furthermore, the sealing structure includes a blind plate connected to the top outlet of the distillation column body.

[0015] Furthermore, a mist catching net is connected to the top of the distillation column.

[0016] Furthermore, the mist catching net is a regular mist catching net.

[0017] Furthermore, the vertical steel pipe and the horizontal steel pipe are seamless steel pipes.

[0018] Furthermore, the free end of the horizontal steel pipe is connected to the exhaust gas external conduit via a flange.

[0019] Furthermore, a cooling structure is connected to the regeneration exhaust gas pipeline.

[0020] Furthermore, the cooling structure includes a cooling coil spirally connected to the regeneration exhaust gas pipeline.

[0021] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0022] (1) The present application provides a blind plate at the top outlet seal of the distillation column body, and provides a steel plate fixedly connected to the pipe wall of the regeneration waste gas pipeline in the distillation column below the cooling coil in the middle of the distillation column, a vertical steel pipe is connected to the middle of the steel plate, and a vertical through hole is provided on the steel plate outside the vertical steel pipe. The vertical steel pipe is connected to the regeneration waste gas pipeline and extends to a side away from the regeneration waste gas pipeline. An elbow steel pipe is fixedly connected to the end of the vertical steel pipe away from the regeneration waste gas pipeline, and a horizontal steel pipe is fixedly connected to the free end of the elbow steel pipe. The free end of the horizontal steel pipe extends to the outside of the distillation column and is fixedly connected to the waste gas outer conduit, thereby realizing the redirection of the waste gas outlet of the rich liquid distillation column of the triethylene glycol open flame heating furnace from the top outlet to the inside downward outlet. The downward waste gas is heat-exchanged again by the cooling coil inside the distillation column and then led out to the waste gas outer conduit through the vertical steel pipe, the elbow steel pipe and the horizontal steel pipe in sequence after heat exchange. Therefore, while realizing the redirection of the waste gas outlet, the waste gas heat exchange cooling effect is increased, and the thermal energy utilization of the waste gas is improved;

[0023] (2) The present application provides a mist catcher fixedly connected to the inner wall of the distillation column above the cooling coil at the top of the distillation column, so that when the evaporated regeneration waste gas passes through the mist catcher, the gaseous triethylene glycol in the regeneration waste gas condenses into droplets in the fine mesh, and the accumulated droplets flow back into the reboiler through the vertical through holes on the vertical steel pipe, thereby effectively reducing the amount of triethylene glycol solution carried away by the regeneration waste gas, thereby reducing the consumption of triethylene glycol solution and improving the economic benefits of the dehydration device, that is, effectively solving the obvious problem of the regeneration waste gas at the top of the distillation column carrying triethylene glycol solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the embodiments of the present utility model, constitute a part of this application, and do not constitute a limitation of the embodiments of the present utility model. In the drawings:

[0025] Figure 1 It is a structural schematic diagram of a distillation column in the prior art;

[0026] Figure 2 It is a schematic structural diagram of a rich liquid distillation column for dehydration of triethylene glycol in the utility model;

[0027] Figure 3 for Figure 2 A magnified view of middle;

[0028] Figure 4 It is a top view of the liquid blocking cylinder;

[0029] Figure 5 It is a front cross-sectional view of the liquid-blocking cylinder.

[0030] Marks and corresponding parts names in the attached drawings:

[0031] 01-distillation column body, 02-regeneration waste gas pipeline, 03-cooling coil, 04-blind plate, 05-mist catcher, 06-vertical steel pipe, 07-elbow steel pipe, 08-horizontal steel pipe, 09-waste gas outer duct, 10-liquid blocking cylinder, 11-steel plate, 12-roof collapse, 13-support column, 14-cofferdam. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0035] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, a connection or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] Example 1

[0037] like Figure 2 to Figure 5As shown, this embodiment provides a rich liquid distillation column for dehydration of triethylene glycol, including a distillation column body 01, the distillation column body 01 is internally connected with a regeneration waste gas pipeline 02, the bottom end of the regeneration waste gas pipeline 02 is connected with a steel plate 11, and the middle part of the steel plate 11 is connected with a vertical steel pipe 06; the vertical steel pipe 06 is communicated with the regeneration waste gas pipeline 02 and extends to a side away from the regeneration waste gas pipeline 02, one end of the vertical steel pipe 06 away from the regeneration waste gas pipeline 02 is fixedly connected with an elbow steel pipe 07, the free end of the elbow steel pipe 07 is fixedly connected with a horizontal steel pipe 08, the free end of the horizontal steel pipe 08 extends to the outside of the distillation column and is fixedly connected to the waste gas outer duct 09; a blind plate 04 is connected to the top outlet of the distillation column body 01.

[0038] Specifically, the top of the distillation column is connected with a regular mist catcher 05. By connecting the regular mist catcher 05 to the top of the distillation column, when the evaporated triethylene glycol solution passes through the regular mist catcher 05, the triethylene glycol entrained in the regeneration waste gas can be condensed into liquid droplets in the fine meshes of the regular mist catcher 05 for reflux.

[0039] Specifically, a liquid blocking cylinder 10 is arranged on the steel plate 11 on one side of the regeneration waste gas pipeline 02, and the liquid blocking cylinder 10 is composed of a cylindrical cofferdam 14, a conical roof 12, and a support column 13, that is, the liquid blocking cylinder 10 is a hollow house structure with a small roof on the top and a large bottom, and the upper end of the liquid blocking cylinder 10 (i.e., the upper end of the cylindrical cofferdam 14) is connected to the regeneration waste gas pipeline 02, and the lower end of the liquid blocking cylinder 10 (i.e., the lower end of the cylindrical cofferdam 14) is connected to the vertical steel pipe 06. With this liquid blocking cylinder 10 structure, the condensed droplets on the mist catching net 05 can be more refluxed to the reboiler, thereby improving the recovery rate of the triethylene glycol solution in the waste gas.

[0040] Specifically, the cylindrical cofferdam 14 has a certain height (15-30 mm), which can prevent the triethylene glycol liquid accumulated on the steel plate from going over the cofferdam 14 and entering the vertical steel pipe 06; the roof 12 is a hollow trapezoidal structure with a small top and a large bottom, and its function is that when the condensed liquid droplets on the mist catching net 05 fall on the roof 12, the droplets flow back to the steel plate along the edge of the roof 12 to prevent them from entering the vertical steel pipe 06. Specifically, the lower part of the liquid blocking cylinder 10 is a cylindrical cofferdam 14, and the upper part is a conical roof 12, and the upper and lower parts of the liquid blocking cylinder 10 are connected by a support column 13; the regenerated waste gas enters the vertical steel pipe 06 from between the upper roof 12 and the cylindrical cofferdam 14; the height of the cylindrical cofferdam 14 is 15-30 mm.

[0041] Specifically, the vertical steel pipe 06 and the horizontal steel pipe 08 are seamless steel pipes, which can effectively lead the exhaust gas out of the distillation column and reduce the pipeline resistance of the exhaust gas discharge.

[0042] Specifically, the free end of the horizontal steel pipe 08 is connected to the exhaust gas outer conduit 09 via a flange, so when the distillation column needs to be inspected and repaired, the flange can be easily removed for implementation, thereby improving the efficiency of inspection and maintenance.

[0043] Specifically, a cooling coil 03 is spirally connected to the regeneration exhaust gas pipeline 02 .

[0044] Compared with the prior art (ref. Figure 1 ), the rich liquid distillation column for triethylene glycol dehydration provided in the present application can realize the redirection of the exhaust gas outlet of the rich liquid distillation column of the triethylene glycol open flame heating furnace, from the top outlet to the internal downward outlet, and the downward exhaust gas is heat-exchanged again by the cooling coil 03 inside the distillation column, and then is led out to the exhaust gas external duct 09 through the vertical steel pipe 06, the elbow steel pipe 07 and the horizontal steel pipe 08 in sequence for discharge, thereby realizing the redirection of the exhaust gas outlet and increasing the exhaust gas heat exchange cooling effect, thereby improving the thermal energy utilization of the exhaust gas.

[0045] In addition, a mist catcher 05 fixedly connected to the inner wall of the distillation column is arranged above the cooling coil 03 at the top of the distillation column, so that when the evaporated regeneration waste gas passes through the mist catcher 05, the gaseous triethylene glycol in the regeneration waste gas condenses into droplets in the fine mesh, and the accumulated droplets flow back to the reboiler through the vertical through holes on the vertical steel pipe 06, thereby effectively reducing the amount of triethylene glycol solution carried away by the regeneration waste gas, thereby reducing the consumption of triethylene glycol solution and improving the economic benefits of the dehydration device, that is, effectively solving the obvious problem of the regeneration waste gas carrying triethylene glycol solution at the top of the distillation column.

[0046] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only the specific implementation method of the utility model and is not used to limit the protection scope of the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A rich liquid distillation column for dehydration of triethylene glycol, comprising a distillation column body (01), wherein the distillation column body (01) is internally connected with a regeneration waste gas pipeline (02), characterized in that: The bottom end of the regeneration waste gas pipeline (02) is connected to a steel plate (11), and the middle part of the steel plate (11) is connected to a vertical steel pipe (06); the vertical steel pipe (06) is in communication with the regeneration waste gas pipeline (02) and extends to a side away from the regeneration waste gas pipeline (02); the end of the vertical steel pipe (06) away from the regeneration waste gas pipeline (02) is fixedly connected to an elbow steel pipe (07), and the free end of the elbow steel pipe (07) is fixedly connected to a horizontal steel pipe (08), and the free end of the horizontal steel pipe (08) extends to the outside of the distillation column and is fixedly connected to the waste gas outer conduit (09); a sealing structure is connected to the top outlet of the distillation column body (01).

2. A rich liquid distillation column for dehydration of triethylene glycol according to claim 1, characterized in that: A liquid blocking cylinder (10) is arranged on the steel plate (11) located on one side of the regeneration waste gas pipeline (02), the upper end of the liquid blocking cylinder (10) is connected to the regeneration waste gas pipeline (02), and the lower end of the liquid blocking cylinder (10) is connected to the vertical steel pipe (06).

3. A rich liquid distillation column for dehydration of triethylene glycol according to claim 2, characterized in that: The lower part of the liquid blocking cylinder (10) is a cylindrical cofferdam (14), and the upper part is a conical roof (12). The upper and lower parts of the liquid blocking cylinder (10) are connected by a support column (13); the regenerated waste gas enters the vertical steel pipe (06) from between the upper roof (12) and the cylindrical cofferdam (14).

4. A rich liquid distillation column for dehydration of triethylene glycol according to claim 1, characterized in that: The sealing structure comprises a blind plate (04) connected to the top outlet of the rectification column body (01).

5. A rich liquid distillation column for dehydration of triethylene glycol according to claim 1, characterized in that: The top of the distillation column is connected with a mist catching net (05).

6. A rich liquid distillation column for dehydration of triethylene glycol according to claim 5, characterized in that: The mist catching net (05) is a regular mist catching net.

7. A rich liquid distillation column for dehydration of triethylene glycol according to claim 1, characterized in that: The vertical steel pipe (06) and the horizontal steel pipe (08) are seamless steel pipes.

8. A rich liquid distillation column for dehydration of triethylene glycol according to claim 1, characterized in that: The free end of the horizontal steel pipe (08) is connected to the exhaust gas outer conduit (09) via a flange.

9. A rich liquid distillation column for dehydration of triethylene glycol according to claim 1, characterized in that: The regeneration waste gas pipeline (02) is connected with a cooling structure.

10. A rich liquid distillation column for dehydration of triethylene glycol according to claim 9, characterized in that: The cooling structure comprises a cooling coil (03) spirally connected to the regeneration exhaust gas pipeline (02).

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