Integrated device for glycol regeneration tail gas and light hydrocarbon recovery

Abstract

The utility model discloses an integrated device for recycling ethylene glycol regeneration tail gas and light hydrocarbon, which can recycle light hydrocarbon enriched in an ethylene glycol flash tank and an ethylene glycol buffer tank, not only improve the purity of ethylene glycol, but also facilitate dehydration of ethylene glycol, simultaneously recycle light hydrocarbon synchronously and improve economic benefits of enterprises. Tail gas generated during regeneration is cooled and then enters a condensate water recovery tank, natural gas at the top of the condensate water recovery tank serves as fuel gas to be combusted in a regeneration tower reboiler, fuel gas consumption is reduced, condensate water at the bottom is output through a conveying pump, and through tail gas recovery treatment, natural gas in the tail gas is removed, so that the tail gas reaches the emission standard; and meanwhile, the potential safety hazard of natural gas emission is reduced.

Description

Technical Field

[0001] The utility model belongs to the field of natural gas purification, and in particular relates to an integrated device for glycol regeneration tail gas and light hydrocarbon recovery. Background Art

[0002] During the recovery of natural gas from scattered wells, it is necessary to dehydrate the natural gas to meet the required water dew point. Glycol absorption dehydration is widely used in the natural gas industry due to its mature process, large processing capacity, and low investment cost.

[0003] The glycol dehydration system mainly includes a natural gas dehydration system and a glycol regeneration system, which is usually used to remove water from glycol (ethylene glycol or propylene glycol, etc.) to obtain higher purity glycol.

[0004] A Chinese patent with authorization announcement number CN206950912U discloses a triethylene glycol regeneration tail gas treatment device, including a first waste gas separator, an air cooler, a second waste gas separator, a first booster and an incinerator; the input end of the first waste gas separator is connected to the triethylene glycol regeneration tail gas, the gas output end is connected to the input end of the air cooler, and the liquid output end is connected to the sewage system; the input end of the second waste gas separator is connected to the output end of the air cooler, the gas output end is connected to the input end of the first booster, and the liquid output end is connected to the sewage system; the output end of the first booster is connected to the input end of the incinerator.

[0005] The above technical solution has the following defects:

[0006] During the operation of the natural gas dehydration system and the glycol regeneration system, light hydrocarbons in the natural gas are easily carried into the glycol regeneration system by the glycol-rich liquid, thereby causing the light hydrocarbons to be enriched in the glycol regeneration system. During the glycol regeneration process, the tail gas at the top of the glycol regeneration tower contains a large amount of unburned stripping gas, which is directly discharged into the venting system without being recycled. The above scheme only provides a recovery function for the regeneration process, but lacks a corresponding recovery function for the enriched light hydrocarbons, which will cause the glycol solution to foam and reduce its cycle life. Utility Model Content

[0007] In view of the above defects, the present invention provides an integrated device for glycol regeneration tail gas and light hydrocarbon recovery, comprising a light hydrocarbon recovery tank, a glycol regeneration tower and a glycol flash tank, the delivery end of the glycol rich liquid is connected to the input end of the light hydrocarbon recovery tank and the input end of the glycol regeneration tower respectively through a diverter pipe, a shut-off valve is installed between the diverter pipe and the glycol regeneration tower, the output end of the light hydrocarbon recovery tank is connected to a delivery pump, the top exhaust port of the glycol regeneration tower is connected to a tail gas condenser, the tail gas condenser is connected to a condensate recovery tank, the bottom outlet of the condensate recovery tank is connected to the delivery pump, the top outlet of the condensate recovery tank is connected to a reboiler, and the top outlet of the glycol flash tank is also connected to the reboiler The output end of the reboiler is connected to the lean glycol cooler and the glycol buffer tank in sequence, the outlet at the bottom of the glycol buffer tank is connected to the lean and rich glycol heat exchanger, the top outlet of the glycol buffer tank is connected to the input end of the light hydrocarbon recovery tank through a finned tube, and the bottom outlet of the glycol flash tank is also connected to the input end of the light hydrocarbon recovery tank through a finned tube. The bottom outlet of the glycol flash tank is connected to the lean and rich glycol heat exchanger through a pre-filter, an activated carbon filter, and a post-filter in sequence. The right outlet of the lean and rich glycol heat exchanger is connected to the bottom end of the glycol regeneration tower, and the left outlet of the lean and rich glycol heat exchanger is connected to a lean glycol circulation pump for pressurization, and the lean glycol circulation pump is connected to the glycol dehydration system.

[0008] Furthermore, the delivery pump is a multimedia delivery pump.

[0009] Through the above technical solution, the alternating export of condensed water and light hydrocarbons can be achieved.

[0010] Furthermore, a thermometer is installed inside the light hydrocarbon recovery tank.

[0011] Through the above technical solution, real-time monitoring of the light hydrocarbon temperature is achieved, and the light hydrocarbon can be exported after it has cooled down.

[0012] Furthermore, interface liquid level meters are installed at both the glycol flash tank and the glycol buffer tank.

[0013] The above technical solution makes it easy to observe the internal liquid level.

[0014] Furthermore, a heat exchange tube is installed in the light hydrocarbon recovery tank.

[0015] Through the above technical solution, high-temperature light hydrocarbons are used to preheat the glycol rich liquid, reduce the temperature of recovered light hydrocarbons, and improve the safety of light hydrocarbon storage; at the same time, the glycol rich liquid is heated to reduce the heat load of the system.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This light hydrocarbon tail gas recovery process can recover light hydrocarbons enriched in the glycol flash tank and glycol buffer tank, which not only improves the purity of glycol but also facilitates glycol dehydration; at the same time, it can also simultaneously recover light hydrocarbons, thereby improving the economic benefits of the enterprise.

[0018] 2. The tail gas at the top of the glycol regeneration tower is cooled by the tail gas condenser and then enters the condensate recovery tank. The natural gas at the top of the condensate recovery tank is used as fuel gas to be burned in the reboiler of the regeneration tower, saving fuel gas consumption. The condensed water at the bottom is transported out through the delivery pump and processed through tail gas recovery. This not only removes the natural gas from the tail gas, but also makes the tail gas meet the emission standards and environmental protection requirements, and at the same time reduces the safety risks of natural gas emissions.

[0019] 3. The inlet pipeline of the light hydrocarbon recovery tank is equipped with finned tubes, which can effectively enhance the heat exchange effect with the environment. In addition, the light hydrocarbon recovery tank is equipped with heat exchange tubes, which use high-temperature light hydrocarbons to preheat the glycol rich liquid, reduce the temperature of recovered light hydrocarbons, and improve the safety of light hydrocarbon storage; at the same time, the glycol rich liquid is heated to reduce the heat load of the system.

[0020] 4. Recover the natural gas from the glycol flash tank and use it as fuel gas to burn in the reboiler of the regeneration tower, thus saving fuel gas consumption.

[0021] 5. The light hydrocarbon tail gas recovery process is simple and technologically advanced. It can be used in conjunction with conventional glycol regeneration equipment and can also improve the current glycol dehydration regeneration process. It requires relatively little change to the existing glycol regeneration process and has wide promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flowchart of the utility model.

[0023] In the figure: 1. Glycol regeneration tower; 2. Glycol flash tank; 3. Pre-filter; 4. Activated carbon filter; 5. Post-filter; 6. Lean and rich glycol heat exchanger; 7. Reboiler; 8. Lean glycol cooler; 9. Glycol buffer tank; 10. Lean glycol circulation pump; 11. Shut-off valve; 12. Fin tube; 13. Light hydrocarbon recovery tank; 14. Tail gas condenser; 15. Condensate recovery tank; 16. Transfer pump. DETAILED DESCRIPTION

[0024] To facilitate understanding of the present invention, the following description of the present invention is more comprehensive, with reference to the accompanying drawings. The drawings illustrate embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0025] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "disposed" should be understood in a broad sense. For example, they may refer to fixed connection or disposition, detachable connection or disposition, or integral connection or disposition. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0026] Example

[0027] like Figure 1 As shown, this embodiment provides an integrated device for glycol regeneration tail gas and light hydrocarbon recovery, including a light hydrocarbon recovery tank 13, a glycol regeneration tower 1 and a glycol flash tank 2. A thermometer is installed inside the light hydrocarbon recovery tank 13 to realize real-time monitoring of the light hydrocarbon temperature. When the light hydrocarbon is cooled, it is transported out. The delivery end of the glycol rich liquid is connected to the input end of the light hydrocarbon recovery tank 13 and the input end of the glycol regeneration tower 1 respectively through a diversion pipe. A shut-off valve 11 is installed between the diversion pipe and the glycol regeneration tower 1. The output end of the light hydrocarbon recovery tank 13 is connected to a delivery pump 16. In detail, the delivery pump 16 is a multi-media delivery pump that can meet the delivery requirements of condensate and light hydrocarbon media. The delivery pump 16 cooperates with the liquid levels of the light hydrocarbon recovery tank 13 and the condensate recovery tank 15, that is, once the respective preset liquid levels are reached, the product can be transported out, which greatly reduces equipment investment and improves economic benefits.

[0028] The top exhaust port of the glycol regeneration tower 1 is connected to the tail gas condenser 14, the tail gas condenser 14 is connected to the condensate recovery tank 15, and the bottom outlet of the condensate recovery tank 15 is connected to the delivery pump 16, which can realize the alternating external transmission of condensate and light hydrocarbons; the top outlet of the condensate recovery tank 15 is connected to the reboiler 7, and the top outlet of the glycol flash tank 2 is also connected to the reboiler 7. The output end of the reboiler 7 is connected to the lean glycol cooler 8 and the glycol buffer tank 9 in sequence. The glycol flash tank 2 and the glycol buffer tank 9 are both equipped with interface liquid level gauges to facilitate observation of the internal liquid level. The outlet at the bottom of the glycol buffer tank 9 is connected to the lean and rich glycol heat exchanger 6, and the top outlet of the glycol buffer tank 9 is connected to the light hydrocarbon recovery tank 13 through the finned tube 12. The bottom outlet of the glycol flash tank 2 is also connected to the input end of the light hydrocarbon recovery tank 13 through the finned tube 12. The bottom outlet of the glycol flash tank 2 is connected to the poor-rich glycol heat exchanger 6 through the pre-filter 3, the activated carbon filter 4, and the post-filter 5 in sequence, wherein the pre-filter 3, the activated carbon filter 4, and the post-filter 5 filter the obtained rich glycol in sequence. The right outlet of the poor-rich glycol heat exchanger 6 is connected to the bottom end of the glycol regeneration tower 1, so that the poor glycol is regenerated after heat exchange. The left outlet of the poor-rich glycol heat exchanger 6 is connected to a poor glycol circulation pump 10 for pressurization. The poor glycol circulation pump 10 is connected to the glycol dehydration system, so that the poor glycol can be pressurized and discharged into the glycol dehydration system for recovery.

[0029] It should be noted that a heat exchange tube is installed in the light hydrocarbon recovery tank 13, which uses high-temperature light hydrocarbons to preheat the glycol rich liquid, reduce the temperature of the recovered light hydrocarbons, and improve the safety of light hydrocarbon storage; at the same time, the glycol rich liquid is heated to reduce the system heat load.

[0030] It should be noted that all equipment, valves and pipelines of the scattered well glycol regeneration tail gas and light hydrocarbon recovery process in the above embodiment are placed on a skid base, which is a skid-mounted light hydrocarbon recovery facility. The relocation and disassembly work volume is small, and it has wide promotion significance.

[0031] The present embodiment describes an integrated device for glycol regeneration tail gas and light hydrocarbon recovery. During glycol regeneration, the shut-off valve 11 is first closed, and the glycol rich liquid enters the heat exchange tube provided in the light hydrocarbon recovery tank 13, exchanges heat with the high-temperature light hydrocarbons in the tank, and then enters the top of the glycol regeneration tower 1 for regeneration; during the regeneration process, the light hydrocarbons brought in by the glycol rich liquid will be enriched in the glycol flash tank 2 and the glycol buffer tank 9. When the light hydrocarbons are enriched more, the light hydrocarbons in the glycol flash tank 2 and the glycol buffer tank 9 flow into the light hydrocarbon recovery tank 13 through the pipeline, and pass through the finned tube 12 to enhance the heat exchange effect with the ambient air, thereby achieving preliminary cooling of the recovered light hydrocarbons. The light hydrocarbons further exchange heat with the glycol rich liquid in the internal heat exchange tube in the light hydrocarbon recovery tank 13, and their temperature is effectively reduced; when the liquid level in the light hydrocarbon recovery tank 13 is high, the light hydrocarbons flow into the delivery pump 16 through the pipeline, thereby achieving external transportation of the light hydrocarbons;

[0032] At the same time, during the glycol regeneration process, the exhaust gas contains a large amount of unburned stripping gas. The exhaust gas from the top of the glycol regeneration tower 1 first enters the exhaust gas condenser 14, and after being cooled by the exhaust gas condenser 14, it becomes a gas-liquid two-phase, and then enters the condensate recovery tank 15. The top outlet of the condensate recovery tank 15 discharges the recovered natural gas into the reboiler 7 for combustion, and the bottom outlet discharges the condensate through the transfer pump 16.

[0033] After the glycol rich liquid passes through the glycol flash tank 2, part of the natural gas carried in the rich liquid will be separated, and the natural gas is discharged into the reboiler 7 through the top outlet of the glycol flash tank 2. The high-temperature lean glycol discharged from the reboiler 7 is cooled by the lean glycol cooler 8 through heat exchange, and then enters the lean glycol buffer tank 9 for separation. The natural gas containing heavy hydrocarbons at the top of the lean glycol buffer tank 9 is cooled by the finned tube 12, and the lean glycol at the bottom of the lean glycol buffer tank 9 enters the poor-rich glycol heat exchanger 6 for heat exchange with the rich glycol. The rich glycol comes from the bottom of the glycol flash tank 2, is filtered in sequence by the pre-filter 3, the activated carbon filter 4, and the post-filter 5, and then heat exchanged with the lean glycol in the poor-rich glycol heat exchanger 6. After being heated, the rich glycol enters the glycol regeneration tower 1 for regeneration. The lean glycol cooled by the poor-rich glycol heat exchanger 6 is pressurized by the lean glycol circulation pump 10 and then sent to the glycol dehydration system for subsequent dehydration treatment.

[0034] It should be noted that the structure described in the present invention can be implemented in a variety of different forms and is not limited to the described embodiments. Any equivalent transformations made by ordinary technicians in this field using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technical fields, such as the loading and unloading of other items, are included in the scope of protection of the present invention.

Claims

1. An integrated device for glycol regeneration tail gas and light hydrocarbon recovery, comprising a light hydrocarbon recovery tank, a glycol regeneration tower and a glycol flash tank, characterized in that: The delivery end of the glycol rich liquid is connected to the input end of the light hydrocarbon recovery tank and the input end of the glycol regeneration tower respectively through a diverter pipe. A shut-off valve is installed between the diverter pipe and the glycol regeneration tower. The output end of the light hydrocarbon recovery tank is connected to a delivery pump, and the top exhaust port of the glycol regeneration tower is connected to a tail gas condenser. The tail gas condenser is connected to a condensate recovery tank. The bottom outlet of the condensate recovery tank is connected to the delivery pump, and the top outlet of the condensate recovery tank is connected to a reboiler. The top outlet of the glycol flash tank is also connected to the reboiler. The output end of the reboiler is connected to a lean glycol cooler and a glycol buffer tank in sequence. The bottom outlet of the glycol buffer tank is connected to the poor-rich glycol heat exchanger, the top outlet of the glycol buffer tank is connected to the input end of the light hydrocarbon recovery tank through a finned tube, and the bottom outlet of the glycol flash tank is also connected to the input end of the light hydrocarbon recovery tank through a finned tube. The bottom outlet of the glycol flash tank is connected to the poor-rich glycol heat exchanger through a pre-filter, an activated carbon filter, and a post-filter in sequence. The right outlet of the poor-rich glycol heat exchanger is connected to the bottom end of the glycol regeneration tower, and the left outlet of the poor-rich glycol heat exchanger is connected to a poor glycol circulation pump for pressurization, and the poor glycol circulation pump is connected to the glycol dehydration system.

2. The integrated device for glycol regeneration tail gas and light hydrocarbon recovery according to claim 1, characterized in that: The delivery pump is a multimedia delivery pump.

3. The integrated device for glycol regeneration tail gas and light hydrocarbon recovery according to claim 1, characterized in that: A thermometer is installed inside the light hydrocarbon recovery tank.

4. The integrated device for glycol regeneration tail gas and light hydrocarbon recovery according to claim 1, characterized in that: Interface liquid level meters are installed at the glycol flash tank and the glycol buffer tank.

5. The integrated device for glycol regeneration tail gas and light hydrocarbon recovery according to claim 1, characterized in that: A heat exchange tube is installed in the light hydrocarbon recovery tank.

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