A method and system for natural gas dehydration

Abstract

The present application relates to a kind of natural gas dehydration method and system.The method includes: natural gas raw gas and triethylene glycol raw material are sent into liquid drop atomization area, obtain mixture, mixture is sequentially treated by gas-liquid mass transfer area, gas-liquid mixing area and gas-liquid separation area, and obtain dehydrated natural gas and liquid material, the distance between the gas flow rate / static mixer of natural gas raw gas and liquid drop atomizer≤10.The present application can increase gas-liquid contact specific surface area, change gas-liquid flow state, increase overall volumetric mass transfer coefficient, enhance gas-liquid two-phase mass transfer process, and then effectively separate water in natural gas.

Description

Technical Field

[0001] This invention belongs to the field of chemical production technology, specifically relating to a method and system for natural gas dehydration. Background Technology

[0002] Natural gas is a general term for a mixture of gases, primarily hydrocarbons, found in underground rock reservoirs. It is lighter than air and possesses properties such as being colorless, odorless, and non-toxic. Using natural gas as an energy source can reduce the consumption of coal and oil, alleviating environmental pollution. As a clean energy source, natural gas can reduce sulfur dioxide and particulate matter emissions by nearly 100%, carbon dioxide emissions by 60%, and nitrogen oxide emissions by 50%. It also helps reduce acid rain formation, mitigate the greenhouse effect, and fundamentally improve environmental quality. As a vehicle fuel, natural gas has advantages such as high calorific value, low exhaust pollution, reliable supply, and low price, making it a leading clean fuel for vehicles worldwide.

[0003] However, natural gas contains moisture, and this residual moisture must be removed before it is transported to pipelines for distribution. This residual moisture poses several hazards: it reduces the calorific value of the natural gas, decreasing combustion efficiency; it can form natural gas hydrates, reducing pipeline flow area and clogging pipelines, valves, and equipment; and it can combine with acidic gases to corrode pipelines and equipment. Existing natural gas dehydration methods include solid adsorption, cryogenic cooling separation, supersonic dehydration, and solvent absorption. Among these, triethylene glycol (MEG) absorption is commonly used. The principle behind this method is that the triethylene glycol molecule contains hydrophilic hydroxyl groups and ether bonds. These hydroxyl and ether bonds form hydrogen bonds with water, removing trace amounts of moisture from the natural gas. Using MEG absorption for natural gas dehydration offers advantages such as high efficiency and good controllability. However, this method is complex, requires large and numerous pieces of equipment, occupies a large area, and has high energy consumption for triethylene glycol regeneration. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a natural gas dehydration method and system to solve the technical problems existing in the prior art, such as the complex process, large size and number of equipment, large footprint, and high energy consumption for triethylene glycol regeneration, when using the triethylene glycol absorption method to dehydrate natural gas.

[0005] In a first aspect, the present invention provides a natural gas dehydration method, wherein the natural gas dehydration method is carried out in a natural gas dehydration system, the natural gas dehydration system includes a dehydration separation device, the dehydration separation device includes a main pipeline and a branch pipeline connected to the main pipeline, the main pipeline includes a droplet atomization zone, a gas-liquid mass transfer zone, a gas-liquid mixing zone and a gas-liquid separation zone connected in sequence, a droplet atomization zone is provided at the top of the droplet atomization zone, a natural gas inlet is provided at the upper part of the droplet atomization device in the droplet atomization zone, the droplet atomization device is provided with a liquid inlet, the gas-liquid mixing zone is provided with a static mixer, the gas-liquid separation zone is provided with a gas-liquid separator and a gas phase outlet, the gas-liquid separator is provided with a liquid phase outlet, the liquid phase outlet is connected to the branch pipeline, and the droplet atomization zone and the gas-liquid mass transfer zone are connected by a flange.

[0006] The natural gas dehydration method includes:

[0007] Natural gas feedstock and triethylene glycol feedstock are fed into the droplet atomization zone to obtain a mixture. The mixture is then processed sequentially through a gas-liquid mass transfer zone, a gas-liquid mixing zone, and a gas-liquid separation zone to obtain dehydrated natural gas and liquid materials. The gas flow rate of the natural gas feedstock is ≤10 km / h, and the distance between the static mixer and the droplet atomizer is ≤10 km / h.

[0008] It should be noted that in this invention, the gas flow rate of the natural gas feedstock / / distance between the static mixer and the droplet atomizer ≤ 10 refers to the ratio where the gas flow rate is in m / s and the distance between the static mixer and the droplet atomizer is in meters.

[0009] Optionally, the nozzle used in the droplet atomizer is a liquid nozzle.

[0010] Optionally, the natural gas dehydration method further includes: feeding the liquid material into a distillation column for distillation, and feeding the triethylene glycol liquid obtained from the distillation into a droplet atomization zone.

[0011] Optionally, the natural gas dehydration method further includes: feeding preheated purge gas and the liquid material into a stripping tower for stripping, and feeding the stripped triethylene glycol liquid into a droplet atomization zone.

[0012] Optionally, the liquid nozzle may be a single-fluid atomizing nozzle or a two-fluid atomizing nozzle.

[0013] Optionally, the purge gas is selected from at least one of nitrogen, carbon dioxide, and flash vapor.

[0014] Optionally, the mass ratio of the purge gas to the triethylene glycol feedstock is 1:1 to 10.

[0015] Optionally, the liquid nozzle is a two-fluid atomizing nozzle.

[0016] Secondly, the present invention also provides a natural gas dehydration system, the natural gas dehydration system including a dehydration separation device, the dehydration separation device including a main pipeline and a branch pipeline connected to the main pipeline, the main pipeline including a droplet atomization zone, a gas-liquid mass transfer zone, a gas-liquid mixing zone and a gas-liquid separation zone connected in sequence, the droplet atomization zone having a droplet atomizer at the top, a natural gas inlet at the upper part of the droplet atomizer in the droplet atomization zone, the droplet atomizer having a liquid inlet, the gas-liquid mixing zone having a static mixer, the gas-liquid separation zone having a gas-liquid separator and a gas phase outlet, the gas-liquid separator having a liquid phase outlet, the liquid phase outlet being connected to the branch pipeline, and the droplet atomization zone and the gas-liquid mass transfer zone being flanged connected.

[0017] Optionally, the natural gas dehydration system further includes a distillation column, a first condenser, and a water-gas separation mechanism connected together. The distillation column is provided with a feed inlet, a gas outlet, and a liquid outlet. The feed inlet is connected to the branch pipe, the gas outlet is connected to the first condenser, and the liquid outlet is connected to a second condenser. The second condenser is provided with a triethylene glycol liquid outlet, and the triethylene glycol liquid outlet is connected to the liquid inlet.

[0018] Optionally, a triethylene glycol storage container and a triethylene glycol recovery pump are provided on the connecting pipe between the triethylene glycol outlet and the inlet.

[0019] Optionally, the natural gas dehydration system further includes a stripping tower and a triethylene glycol recovery pump connected together. The stripping tower is connected to a purge gas inlet pipe, and a purge gas heater is installed on the purge gas inlet pipe. The stripping tower is connected to the branch pipe, and the triethylene glycol recovery pump is connected to the liquid inlet.

[0020] Optionally, the natural gas dehydration system includes several interconnected stages of dehydration separation equipment, with the gas phase outlet of an adjacent upstream dehydration separation equipment connected to the natural gas inlet of an adjacent downstream dehydration separation equipment.

[0021] Optionally, a triethylene glycol storage container and a feed pump are sequentially installed on the connecting pipe between the triethylene glycol outlet and the inlet.

[0022] Optionally, a triethylene glycol storage container and a feed pump are sequentially installed on the connecting pipe between the triethylene glycol recovery pump and the inlet.

[0023] The beneficial effects of the natural gas dehydration method and system of the present invention are as follows:

[0024] This invention can increase the specific surface area of ​​gas-liquid contact, change the gas-liquid flow state, increase the overall volumetric mass transfer coefficient, enhance the gas-liquid two-phase mass transfer process, and thus effectively separate water from natural gas (triethylene glycol dehydrates natural gas by utilizing the property that the hydroxyl and ether bonds of triethylene glycol can form hydrogen bonds with water to remove trace amounts of water from natural gas).

[0025] The system of the present invention is small in size, occupies a small area, has low investment cost, and is easy to transport and maintain. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the natural gas dehydration system of Example 1;

[0028] Figure 2 for Figure 1 Schematic diagram of the dehydration and separation equipment;

[0029] Figure 3 This is a schematic diagram of the natural gas dehydration system in Example 2;

[0030] Figure 4 This is a schematic diagram of the natural gas dehydration system in Example 3;

[0031] Figure 5 This is a schematic diagram of the natural gas dehydration system in Example 4;

[0032] Figure 6 This is a schematic diagram of the dehydration separation equipment used in the natural gas dehydration system of Example 5.

[0033] Figure Labels

[0034] 1-Dehydration and separation equipment, 11-Droplet atomization zone, 111-Natural gas inlet, 112-Droplet atomizer, 1121-Liquid inlet, 12-Gas-liquid mass transfer zone, 13-Gas-liquid mixing zone, 14-Gas-liquid separation zone, 141-Gas-liquid separator, 15-Flange, 16-Sealing element, 17-Liquid phase buffer zone;

[0035] 2-Distillation column;

[0036] 3-First condenser;

[0037] 4-Water-gas separation mechanism;

[0038] 5-Second condenser;

[0039] 6-Triethylene glycol recovery pump;

[0040] 7-Triethylene glycol storage container;

[0041] 8-Feed pump;

[0042] 9-Centrifugal pump;

[0043] 10-Stripping Tower;

[0044] 11-Purge gas heater. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] Additionally, it should be noted that all directional indicators (such as up, down, top, bottom, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the attached figure). If the specific posture changes, the directional indicator will also change accordingly.

[0048] In this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the word "and / or" throughout the text means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0049] The present invention will be described in detail below through specific examples and embodiments. It should also be understood that the following embodiments are only for specific illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0050] Example 1

[0051] Please see Figure 1 , Figure 1 This is a schematic diagram of the natural gas dehydration system in this embodiment.

[0052] like Figure 1 As shown, the natural gas dehydration system of this embodiment includes a dehydration separation device 1, a distillation column 2, a first condenser 3, a water-gas separation mechanism 4, a second condenser 5, a triethylene glycol recovery pump 6, a triethylene glycol storage container 7, and a feed pump 8.

[0053] Please see Figure 2 The dehydration and separation equipment adopts a pipeline type, which includes a main pipeline and branch pipelines. The main pipeline includes a droplet atomization zone 11, a gas-liquid mass transfer zone 12, a gas-liquid mixing zone 13 and a gas-liquid separation zone 14 connected in sequence.

[0054] Please continue reading. Figure 2 The droplet atomization zone 11 serves as both the intake area for the natural gas to be processed and the area for atomizing triethylene glycol (MEG) into small droplets for thorough mixing with the natural gas in subsequent processes. From top to bottom, the droplet atomization zone 11 includes a natural gas inlet 111 and a droplet atomizer 112. The natural gas inlet 111 is located at the top of the droplet atomization zone 11, and the droplet atomizer 112 is located on the top side wall of the droplet atomization zone 11 in the main pipeline. The droplet atomizer 112 has a liquid inlet 1121. Natural gas to be processed is introduced into the droplet atomization zone 11 through the natural gas inlet 111, and triethylene glycol is introduced into the droplet atomization zone 11 through the droplet atomizer 112. The triethylene glycol is atomized into smaller droplets by the droplet atomizer 112. The nozzle used in the droplet atomizer 112 is a liquid nozzle, which is set in a direction away from the natural gas inlet 111. The liquid nozzle is a single-fluid atomizing nozzle (i.e., a single-fluid atomizing nozzle). The droplet atomizer with a single-fluid atomizing nozzle is existing technology and will not be described in detail here.

[0055] Please continue reading. Figure 2The gas-liquid mass transfer zone 12 serves as a region for sufficient mass transfer between the triethylene glycol droplets and the natural gas to be processed. Within the gas-liquid mass transfer zone 12, the atomized triethylene glycol droplets and the natural gas to be processed flow in the same direction, ensuring full contact between them during the flow. The gas-liquid mass transfer zone 12 is located between the droplet atomization zone 11 and the gas-liquid mixing zone 13, and the gas-liquid mass transfer zone 12 and the droplet atomization zone 11 are connected by a flange 15. The flange is existing technology and will not be described in detail here.

[0056] Specifically, in this embodiment, the gas-liquid mass transfer zone 12 and the droplet atomization zone 11 are connected by a flange to facilitate subsequent maintenance.

[0057] Please continue reading. Figure 2 The gas-liquid mixing zone 13 is used to mix the natural gas to be treated with triethylene glycol droplets. In the gas-liquid mixing zone 13, the hydroxyl and ether bonds of triethylene glycol form hydrogen bonds with trace amounts of water carried in the natural gas to be treated, thereby removing trace amounts of water from the natural gas. The gas-liquid mixing zone 13 is equipped with a static mixer 131, which has an inlet and an outlet. The static mixer 131 is a DSV static mixer, which is existing technology and will not be described in detail here.

[0058] Please continue reading. Figure 2 A flange 15 connects the gas-liquid separation zone 14 and the gas-liquid mixing zone 13. The gas-liquid separation zone 14 is equipped with a gas-liquid separator 141 and a gas phase outlet. The gas-liquid separator 141 is used to separate the gas and liquid phases of the material after mixing in the static mixer 131. The gas-liquid separator 141 has a material inlet and a liquid phase outlet. The liquid phase outlet is connected to a branch pipe so that the liquid material flowing out of the liquid phase outlet can enter the branch pipe. The branch pipe serves as a liquid phase buffer zone 17. The gas-liquid separator is existing technology and will not be described in detail here. A sealing element 16 is provided at the gas phase outlet of the gas-liquid separation zone 14. The sealing element can be a flange. The flange is existing technology and will not be described in detail here.

[0059] The principle of this embodiment is as follows: triethylene glycol dehydrates natural gas by utilizing the property that the hydroxyl and ether bonds of triethylene glycol can form hydrogen bonds with water to remove trace amounts of moisture from the natural gas. This embodiment, by incorporating a droplet atomizer 112, can increase the specific surface area of ​​the gas-liquid contact, change the gas-liquid flow state, increase the overall volumetric mass transfer coefficient, and enhance the gas-liquid two-phase mass transfer process, thereby effectively separating moisture from the natural gas. Furthermore, the equipment of this invention is small in size, occupies a small area, has low investment costs, and is easy to transport and maintain.

[0060] Please continue reading. Figure 1Distillation column 2 is used to distill the liquid material obtained after gas-liquid separation to recover triethylene glycol from the liquid material. Distillation column 2 has a feed inlet, a gas outlet, and a liquid outlet. The feed inlet of distillation column 2 is connected to the liquid phase buffer zone 17, the gas outlet of distillation column 2 is connected to the first end of the first condenser 3, and the liquid outlet of distillation column 2 is connected to the first end of the second condenser 5. The distillation column is existing technology and will not be described in detail here.

[0061] Please continue reading. Figure 1 The first condenser 3 is used to cool the gaseous material obtained after distillation. The first end of the first condenser 3 is connected to the gas outlet of the distillation column 2, and the second end of the first condenser 3 is connected to the first end of the water-gas separation mechanism 4.

[0062] Please continue reading. Figure 1 The water-gas separation mechanism 4 is used to perform gas-liquid separation on the material cooled by the first condenser 3, so as to separate the waste gas (mainly CH4) from the wastewater. The water-gas separation mechanism 4 can be a gas-liquid separator, which is existing technology and will not be described in detail here.

[0063] Please continue reading. Figure 1 The second condenser 5 is used to cool the triethylene glycol obtained after distillation. The second condenser 5 is provided with a triethylene glycol outlet end. The first end of the second condenser 5 is connected to the outlet of the distillation column 2, and the triethylene glycol outlet end of the second condenser 5 is connected to the inlet 1121 of the droplet atomizer 112.

[0064] Please continue reading. Figure 1 The triethylene glycol recovery pump 6, the triethylene glycol storage container 7, and the feed pump 8 are located sequentially on the connecting pipe between the triethylene glycol outlet of the second condenser 5 and the inlet 1121 of the droplet atomizer 112.

[0065] Specifically, this embodiment adds a connected distillation column 2 and a second condenser 5, and connects the triethylene glycol (MEG) outlet of the second condenser 5 to the inlet 1121 of the droplet atomizer 112. This allows for the recovery of MEG through distillation, and the recovered MEG is cooled by the second condenser 5 before being fed into the droplet atomization zone for reuse, thus improving the utilization rate of MEG. By adding a MEG storage container 7 and a feed pump 8 sequentially arranged on the connecting pipe between the MEG outlet and inlet, the recovered MEG can be buffered by the MEG storage container 7, thereby controlling the amount of MEG entering the droplet atomization zone. This avoids the technical problem of poor mixing between MEG and natural gas in the droplet atomization zone and ineffective separation of moisture from natural gas due to excessive MEG intake.

[0066] Example 2

[0067] Please see Figure 3 , Figure 3This is a schematic diagram of the natural gas dehydration system in this embodiment.

[0068] like Figure 3 As shown, this embodiment is similar to Figure 1 The difference is that it includes at least two stages of dehydration separation equipment 1. The gas phase outlet of the first stage dehydration separation equipment 1 is connected to the natural gas inlet 111 of the second stage dehydration separation equipment 1. The liquid phase buffer 17 of the second stage dehydration separation equipment 1 is connected to the liquid inlet 1121 of the droplet atomizer 112 of the first stage dehydration separation equipment 1. A centrifugal pump 9 is installed on the connecting pipe between the liquid phase buffer 17 of the second stage dehydration separation equipment 1 and the liquid inlet 1121 of the droplet atomizer 112 of the first stage dehydration separation equipment 1. The triethylene glycol storage container 7 is not connected to the liquid inlet 1121 of the droplet atomizer 112 of the first stage dehydration separation equipment 1. The triethylene glycol storage container 7 is connected to the liquid inlet 1121 of the droplet atomizer 112 of the second stage dehydration separation equipment 1.

[0069] Specifically, this embodiment sets the natural gas dehydration system to include two-stage dehydration separation equipment 1, and connects the gas phase outlet of the first-stage dehydration separation equipment 1 to the natural gas inlet 111 of the second-stage dehydration separation equipment 1. This allows the natural gas that has been dehydrated by the first-stage dehydration separation equipment 1 to be sent into the second-stage dehydration separation equipment 1 to further remove moisture from the natural gas.

[0070] Example 3

[0071] Please see Figure 4 , Figure 4 This is a schematic diagram of the natural gas dehydration system in this embodiment.

[0072] like Figure 4 As shown, the difference between this embodiment and Embodiment 1 is that a stripping column 10 is used instead of a distillation column 2. The stripping column 10 is connected to a purge gas inlet pipe, and a purge gas heater 11 is installed on the purge gas inlet pipe. The stripping column 10 has a feed inlet, a gas outlet, and a liquid outlet. The feed inlet of the stripping column 10 is connected to the liquid phase buffer zone 17 of a branch pipe. The gas outlet of the stripping column 10 is connected to the first end of the first condenser 3, and the liquid outlet of the stripping column 10 is connected to the first end of the second condenser 5. The purge gas can be nitrogen, carbon dioxide, flash vapor, etc., and the mass ratio of the purge gas to triethylene glycol is 1:1 to 10. The stripping column is existing technology and will not be described in detail here.

[0073] Specifically, in this embodiment, by adding a stripping tower 10 and installing a purge gas heater 11 on the purge gas inlet pipe of the stripping tower 10, and connecting the triethylene glycol outlet to the liquid inlet, triethylene glycol can be recovered by high-temperature gas purge stripping and then sent to the droplet atomization zone for reuse through the liquid inlet, thereby improving the utilization rate of triethylene glycol.

[0074] Example 4

[0075] Please see Figure 5 , Figure 5 This is a schematic diagram of the natural gas dehydration system in this embodiment.

[0076] like Figure 5 As shown, the difference between this embodiment and Embodiment 2 is that a stripping column 10 is used instead of a distillation column 2. The stripping column 10 is connected to a purge gas inlet pipe, and a purge gas heater 11 is installed on the purge gas inlet pipe. The stripping column 10 has a feed inlet, a gas outlet, and a liquid outlet. The feed inlet of the stripping column 10 is connected to a liquid phase buffer zone 17, the gas outlet of the stripping column 10 is connected to the first end of the first condenser 3, and the liquid outlet of the stripping column 10 is connected to the first end of the second condenser 5. The stripping column is existing technology and will not be described in detail here.

[0077] Example 5

[0078] Please see Figure 6 , Figure 6 This is a schematic diagram of the natural gas dehydration system in this embodiment.

[0079] like Figure 6 As shown, this embodiment is similar to Figure 1 The difference lies in the fact that the liquid nozzle uses a two-fluid atomizing nozzle, which is existing technology and will not be elaborated here.

[0080] Specifically, in this embodiment, the liquid nozzle is configured as a two-fluid atomizing nozzle. By spraying triethylene glycol liquid into high-speed flowing compressed gas (which enters the droplet atomization zone 11 through another inlet of the two-fluid atomizing nozzle), the triethylene glycol liquid is rapidly broken into small particles to form a mist. This allows for thorough mixing of the compressed gas and triethylene glycol, better control of the spray particle size and uniformity, and finer particle size. Using a two-fluid atomizing nozzle, the triethylene glycol liquid can produce droplets with a particle size of 10 to 100 micrometers, increasing the specific surface area of ​​the triethylene glycol liquid in contact with natural gas. The gas-liquid contact area is 100 to 1000 times that of a traditional absorption tower, thereby more effectively utilizing the hydroxyl and ether bonds of triethylene glycol to separate water from natural gas.

[0081] Example 6

[0082] The system of Example 2 is used to dehydrate natural gas feedstock. The specific steps are as follows:

[0083] The natural gas feedstock and triethylene glycol feedstock are fed into the droplet atomization zone (the single-fluid atomizing nozzle emits liquid with a particle size of 500 μm, a flow velocity of 1 m / s, and a flow rate of 15 m³ / s). 3 / h; gas phase flow rate is 4500m³ / h 3The mixture is obtained at a pressure of 10 MPa / h, where the gas velocity of the natural gas feedstock is 10 m / s (i.e., the volume ratio of triethylene glycol to natural gas feedstock is 1:300). The main and branch pipes of the dehydration separation device 1 have a diameter of 400 mm. The distance between the droplet atomizer 112 and the static mixer 131 is 2500 mm. That is, the ratio of the gas velocity of the natural gas feedstock to L (i.e., the distance between the droplet atomizer 112 and the static mixer 131) is 10 m / s: 2500 mm = 10 m / s: 2.5 m = 4 s. -1 (In actual calculations, the gas velocity of the natural gas feedstock is in m / s, the distance between the droplet atomizer 112 and the static mixer 131 is in m, and the ratio of the gas velocity of the natural gas feedstock to L (i.e., the distance between the droplet atomizer 112 and the static mixer 131) is dimensionless).

[0084] The mixture is processed sequentially through the gas-liquid mass transfer zone, gas-liquid mixing zone and gas-liquid separation zone of the first-stage dehydration and separation equipment 1 to obtain dehydrated natural gas and liquid material. The dew point of the dehydrated natural gas is -54℃ after testing (using a natural gas dew point meter).

[0085] The dehydrated natural gas is fed into the second-stage dehydration and separation unit 1 to further remove moisture, yielding product natural gas and liquid material.

[0086] The liquid material discharged from the liquid phase buffer 17 of the first-stage dehydration separation device 1 is sent to the distillation column for distillation. The triethylene glycol liquid obtained after distillation is cooled by the second condenser 5 and then pumped to the triethylene glycol storage container 7 by the triethylene glycol recovery pump. Subsequently, it is pumped by the feed pump 8 through the liquid inlet 1121 to the droplet atomizer 112 of the second-stage dehydration separation device 1.

[0087] The liquid phase buffer zone 17 is connected to the liquid inlet 1121 of the droplet atomizer 112 of the first-stage dehydration and separation device 1;

[0088] The liquid material discharged from the liquid phase buffer 17 of the second-stage dehydration and separation device 1 is pumped through the liquid inlet 1121 to the droplet atomizer 112 of the first-stage dehydration and separation device 1 for reuse.

[0089] Example 7

[0090] The difference between this embodiment and Embodiment 6 is that the distance between the droplet atomizer 112 and the static mixer 131 is 2000mm, and the ratio of the gas flow rate of the natural gas feedstock to L (i.e., the distance between the droplet atomizer 112 and the static mixer 131) is 10m / s:2000mm = 10m / s:2m = 5s. -1The processing volume ratio of triethylene glycol to natural gas feedstock was 1:300. The dew point of the dehydrated natural gas was measured to be -26℃ using a natural gas dew point meter.

[0091] Example 8

[0092] The difference between this embodiment and Embodiment 6 is that the distance between the droplet atomizer 112 and the static mixer 131 is 1500mm, and the ratio of the gas flow rate of the natural gas feedstock to L (i.e., the distance between the droplet atomizer 112 and the static mixer 131) is 10m / s : 1500mm = 10m / s : 1.5m = 6.67s. -1 The processing volume ratio of triethylene glycol to natural gas feedstock was 1:300. The dew point of the dehydrated natural gas was measured to be -15℃ using a natural gas dew point meter.

[0093] Example 9

[0094] The difference between this embodiment and Embodiment 6 is that the distance between the droplet atomizer 112 and the static mixer 131 is 1000mm, and the ratio of the gas flow rate of the natural gas feedstock to L (i.e., the distance between the droplet atomizer 112 and the static mixer 131) is 10m / s:1000mm = 10m / s:1m = 10 -1 The processing volume ratio of triethylene glycol to natural gas feedstock was 1:300. The dew point of the dehydrated natural gas was measured to be -9℃ using a natural gas dew point meter.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 6 is that the ratio of the gas flow rate of the natural gas feedstock to L (i.e., the distance between the droplet atomizer 112 and the static mixer 131) is 900 mm: 10 m / s : 900 mm = 10 m / s : 0.9 m = 11.1 s. -1 The processing volume ratio of triethylene glycol to natural gas feedstock was 1:300. The dew point of the dehydrated natural gas was measured to be -3℃ using a natural gas dew point meter.

[0097] As shown in Examples 6-9 and Comparative Example 1, in Examples 6-9, the gas flow rate of the natural gas feedstock / the distance between the droplet atomizer 112 and the static mixer 131 is ≤10, and the dew point of the dehydrated natural gas is -54℃ to -9℃; in Comparative Example 1, the gas flow rate of the natural gas feedstock / the distance between the droplet atomizer 112 and the static mixer 131 is >10 (specifically 11.1), and the dew point of the dehydrated natural gas is -3℃. That is, compared with Examples 6-9, the dew point of the dehydrated natural gas significantly increases after treatment with Comparative Example 1. This result indicates that in this invention, controlling the gas flow rate of the natural gas feedstock / the distance between the droplet atomizer 112 and the static mixer 131 to ≤10 helps improve the dehydration effect of natural gas.

[0098] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for dehydrating natural gas, characterized in that, The natural gas dehydration method is carried out in a natural gas dehydration system, which includes a dehydration separation device. The dehydration separation device includes a main pipeline and a branch pipeline connected to the main pipeline. The main pipeline includes a droplet atomization zone, a gas-liquid mass transfer zone, a gas-liquid mixing zone, and a gas-liquid separation zone connected in sequence. A droplet atomizer is provided at the top of the droplet atomization zone. A natural gas inlet is provided at the upper part of the droplet atomizer in the droplet atomization zone. The droplet atomizer is provided with a liquid inlet. A static mixer is provided in the gas-liquid mixing zone. A gas-liquid separation zone is provided with a gas-liquid separator and a gas phase outlet. The gas-liquid separator is provided with a liquid phase outlet, which is connected to the branch pipeline. A flange connection is made between the droplet atomization zone and the gas-liquid mass transfer zone. The natural gas dehydration method includes: Natural gas feedstock and triethylene glycol feedstock are fed into the droplet atomization zone to obtain a mixture. The mixture is then processed sequentially through a gas-liquid mass transfer zone, a gas-liquid mixing zone, and a gas-liquid separation zone to obtain dehydrated natural gas and liquid material. The gas flow rate of the natural gas feedstock / distance between the static mixer and the droplet atomizer is ≤10s. -1 .

2. The natural gas dehydration method as described in claim 1, characterized in that, The droplet atomizer uses a liquid nozzle.

3. The natural gas dehydration method as described in claim 2, characterized in that, The liquid nozzle is a single-fluid atomizing nozzle and / or a two-fluid atomizing nozzle.

4. The natural gas dehydration method as described in claim 3, characterized in that, The liquid nozzle is a two-fluid atomizing nozzle.

5. The natural gas dehydration method as described in claim 1, characterized in that, The natural gas dehydration method further includes: feeding the liquid material into a distillation column for distillation, and feeding the triethylene glycol liquid obtained from the distillation into a droplet atomization zone.

6. The natural gas dehydration method as described in claim 1, characterized in that, The natural gas dehydration method further includes: feeding preheated purge gas and the liquid material into a stripping tower for stripping, and feeding the stripped triethylene glycol liquid into a droplet atomization zone.

7. The natural gas dehydration method as described in claim 6, characterized in that, The purging gas is selected from at least one of nitrogen, carbon dioxide, and flash vapor.

8. The natural gas dehydration method as described in claim 6, characterized in that, The mass ratio of the purging gas to the triethylene glycol feedstock is 1:1~10.

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