Method for dehydration of an aqueous gas, its use and method for dehydration of natural gas

Abstract

The present application relates to the field of gas drying, in particular to a method for dehydrating water-containing gas, application of the method and a method for dehydrating natural gas, which comprises feeding the water-containing gas into M first type separation units and N second type separation units; wherein M>=1 and N>=1; the first type separation unit comprises a hydrophilic component; the second type separation unit comprises a hydrophobic component, and the first type separation unit and the second type separation unit are arranged in any combination. The present application can effectively remove water in the water-containing gas and significantly reduce the water-carrying capacity of foam. The present application is suitable for dehydrating natural gas, especially for dehydrating natural gas produced by using the foam drainage method, and can efficiently eliminate water foam and remove water in the natural gas.

Description

Technical Field

[0001] This invention relates to the field of gas drying, and more specifically to a method for dehydrating water-containing gases and its application, and a method for dehydrating natural gas. Background Technology

[0002] Water seepage is a common occurrence during natural gas extraction. If the water in the extracted well is not drained in time, it can cause flooding, leading to decreased natural gas production, a lower gas-liquid ratio, and in severe cases, well shutdown. Therefore, natural gas wells need timely drainage. Common drainage technologies include plunger drainage, foam drainage, and electric submersible pump drainage. However, all these technologies result in a large amount of water instantly entering the gas-liquid separator, reducing its efficiency and even causing water to overflow the outlet pipe. Ultimately, a large amount of underground brine is carried by the natural gas into the transportation pipeline and eventually to the natural gas processing station. This brine can cause a series of problems, such as pipeline blockage, accelerated corrosion of pipelines and equipment, increased natural gas drying costs, and damage to equipment due to salt particles left after drying. Therefore, natural gas dehydration equipment is needed to reduce the moisture content in the natural gas. Currently, commonly used dehydration devices in natural gas stations include triethylene glycol drying towers, ethylene glycol drying towers, and solid dryer towers. However, when a large amount of moisture enters these drying towers, it can cause a decrease in dehydration efficiency, an increase in triethylene glycol regeneration energy consumption, and in severe cases, tower failure. Most importantly, this dehydration process inevitably produces salt particles, which can damage the normal operation of the equipment. While membrane dehydration processes can avoid the generation of salt particles, the membrane material has low mechanical strength and small pores. When a large amount of brine, especially water foam, enters, it will block the pores, leading to significant pressure loss, and the strong pressure differential will also damage the membrane material. Summary of the Invention

[0003] To address the aforementioned deficiencies in the prior art, this invention provides a method for dehydrating water-containing gases and its applications, as well as a method for dehydrating natural gas. This method can effectively avoid the generation of salt particles and efficiently eliminate water foam, and it features high dehydration efficiency, low cost, and simple process.

[0004] In a first aspect, the present invention provides a method for dehydrating water-containing gas, wherein the water-containing gas is passed into M first-type separation units and N second-type separation units; wherein, M≥1 and N≥1;

[0005] The first type of separation unit includes a hydrophilic component; the second type of separation unit includes a hydrophobic component, and the first type of separation unit and the second type of separation unit can be arranged and combined arbitrarily.

[0006] Secondly, the present invention provides an application of the method described in natural gas dehydration.

[0007] Thirdly, the present invention provides a method for dehydrating natural gas, the method comprising: dehydrating natural gas according to the dehydration method of the present invention; wherein the water content of the water-containing natural gas is 0.1-50% by weight, preferably 1-25% by weight, more preferably 10-25% by weight; and / or the water-containing natural gas contains water foam.

[0008] Research has shown that hydrophilic components can effectively absorb moisture from water-containing gases, not only reducing the water content but also disrupting the stability of water foam and reducing the water-carrying capacity of the foam. Hydrophobic components can effectively block the passage of moisture and create a larger liquid-solid surface energy, further disrupting the stability of the water foam. Hydrophilic-hydrophobic composite components can interrupt the continuous flow channels of the aqueous phase, increasing the tortuosity of aqueous phase transport and reducing the relative permeability of the aqueous phase, while having almost no impact on gas phase transport. Therefore, this invention, through the combined use of hydrophilic, hydrophobic, and optionally composite components, can effectively remove moisture from water-containing gases and significantly reduce the water-carrying capacity of the foam.

[0009] This invention is applicable to the dehydration of natural gas, especially to the dehydration of natural gas produced by the foam drainage method. It can efficiently eliminate water foam and remove moisture from natural gas, avoiding negative impacts such as salt particles, pipeline corrosion, increased transmission pressure, and increased difficulty in subsequent processing. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a natural gas dehydration device according to a preferred embodiment provided in Example 1;

[0011] Figure 2 This is a schematic diagram of a natural gas dehydration device according to a preferred embodiment provided in Example 2;

[0012] Figure 3 This is a schematic diagram of a natural gas dehydration device according to a preferred embodiment provided in Example 3;

[0013] Figure 4 This is a schematic diagram of a preferred embodiment of a natural gas dehydration device provided in Example 4;

[0014] Figure 5 This is a schematic diagram of a natural gas dehydration device according to a preferred embodiment provided in Example 5.

[0015] Explanation of reference numerals in the attached figures

[0016] Figure 4 In the diagram, 1 is the dehydrator inlet; 2 is the hydrophilic layer; 3 is the hydrophilic-hydrophobic layer; 4 is the hydrophobic layer; 5 is the hollow fixed seal; 6 is the dehydrator outlet; 7 is the water tank; and 8 is the drain valve.

[0017] Figure 5 In the diagram, 1 is the dehydration tower inlet; 2 is the drain valve; 3 is the hydrophilic layer; 4 is the hydrophilic-hydrophobic layer; 5 is the hydrophobic layer; and 6 is the dehydration tower outlet. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0019] In this invention, unless otherwise specified, the "lower part" of a component refers to 70-100% of the component from top to bottom; the "upper part" of a component refers to 0-30% of the component from top to bottom; and the "middle part" of a component refers to 30-70% of the component from top to bottom.

[0020] As mentioned above, the present invention provides a method for dehydrating water-containing gas, the method comprising passing the water-containing gas into M first-type separation units and N second-type separation units; wherein, M≥1, N≥1;

[0021] The first type of separation unit includes a hydrophilic component; the second type of separation unit includes a hydrophobic component, and the first type of separation unit and the second type of separation unit can be arranged and combined arbitrarily.

[0022] In this invention, the hydrophilic component can effectively absorb moisture from the water-containing gas, which not only reduces the water content in the water-containing gas but also disrupts the stability of the water foam and reduces the water-carrying capacity of the foam. The hydrophobic component can effectively block the passage of moisture and create a larger liquid-solid surface energy to further disrupt the stability of the water foam. The hydrophilic-hydrophobic composite component can cut off the continuous channel of the water phase flow, increase the tortuosity of the water phase transport, and reduce the relative permeability of the water phase, while having almost no effect on the gas phase transport. Through the combined use of the hydrophilic component, the hydrophobic component, and their composite component, moisture in the water-containing gas can be effectively removed, significantly reducing the water-carrying capacity of the foam.

[0023] According to a preferred embodiment of the present invention, 1≤M≤100, 1≤N≤100; preferably, 1≤M≤10, 1≤N≤10.

[0024] According to a preferred embodiment of the present invention, the gas in the water-containing gas is selected from one or more of natural gas, methane, nitrogen, and carbon dioxide.

[0025] In this invention, as long as the objective of this invention can be achieved, the water content of the water-containing gas is not particularly required. According to a preferred embodiment of this invention, the water content of the water-containing gas is 0.1-50% by weight, preferably 1-25% by weight, and more preferably 10-25% by weight. By adopting the aforementioned preferred scheme, the dehydration efficiency of the water-containing gas can be further improved.

[0026] In this invention, the hydrophilic and hydrophobic components can be conventional choices in the art. According to a preferred embodiment of the invention, the hydrophilic component is a first-type contact element modified with a hydrophilic modifier. By adopting the aforementioned preferred solution, the dehydration efficiency of water-containing gases can be further improved.

[0027] According to a preferred embodiment of the present invention, the hydrophobic component is a second type of contact component modified with a hydrophobic modifier. By adopting the aforementioned preferred solution, the dehydration efficiency of water-containing gases can be further improved.

[0028] According to a preferred embodiment of the present invention, the hydrophilic component and the hydrophobic component are each provided with through holes, and the porosity is 20%-90%, preferably 30%-60%. By adopting the aforementioned preferred solution, the dehydration efficiency of water-containing gas can be further improved.

[0029] In this invention, the hydrophilic modifier can be a conventional choice in the art. According to a preferred embodiment of the invention, the hydrophilic modifier is selected from at least one of the following: hydrophilic polymers, hydrophilic dyes, hydrophilic silanes, ionic surfactants with a concentration higher than the critical micelle concentration, polyether nonionic surfactants, metal oxides, quaternary ammonium compounds, nanoparticles grafted with ionic groups, nanoparticles grafted with hydroxyl groups, proteins, cellulose, and hydrophilic paints. Preferably, it is at least one of hydrophilic polymers, hydrophilic dyes, and hydrophilic silanes; more preferably, it is at least one of polyvinylpyrrolidone, polyhydroxyalkyl azo, and polyether silanes. By adopting the aforementioned preferred embodiment, the dehydration efficiency of water-containing gases can be further improved.

[0030] In this invention, the hydrophobic modifier can be a conventional choice in the art. According to a preferred embodiment of the invention, the hydrophobic modifier is selected from at least one of fluorosilane-based chemicals, hydrophobic polymers, ionic surfactants with concentrations below the critical micelle concentration, fluorinated surfactants, alkyl-grafted nanoparticles, aromatic hydrocarbon-grafted nanoparticles, and oleophilic paints. Preferably, it is at least one of fluorosilane-based chemicals, hydrophobic polymers, and ionic surfactants with concentrations below the critical micelle concentration; more preferably, it is at least one of perfluorosilanes and polytetrafluoroethylene. By adopting the aforementioned preferred scheme, the dehydration efficiency of water-containing gases can be further improved.

[0031] In this invention, the types of the first and second types of contact elements are not particularly required as long as the objective of the invention can be achieved. According to a preferred embodiment of the invention, the first and second types of contact elements are each selected from one or more of baffles, coalescing plates, rectifiers, packing, trays, and filters. By adopting the aforementioned preferred solution, the dehydration efficiency of water-containing gases can be further improved.

[0032] In this invention, the forming materials of the first type of contact and the second type of contact can be conventional choices in the art. According to a preferred embodiment of the invention, the forming materials of the first type of contact and the second type of contact are each selected from one or more of metal, ceramic, glass, cotton fiber, polyamide fiber, polyester fiber, or wood. By adopting the aforementioned preferred solution, the dehydration efficiency of water-containing gas can be further improved.

[0033] According to a preferred embodiment of the present invention, the first type of contact element and the second type of contact element are at least one of ceramic packing, metal mesh, polyester filter cloth and cotton filter cloth.

[0034] In this invention, the modification method can be any method in the art. According to a preferred embodiment of the invention, the modification method is selected from one or both of chemical and physical methods, preferably at least one of soaking, coating, adsorption, and etching. By adopting the aforementioned preferred scheme, the dehydration efficiency of water-containing gases can be further improved.

[0035] According to a preferred embodiment of the present invention, the method includes: passing water-containing gas into M first-type separation units, N second-type separation units, and L third-type separation units, wherein the first-type separation units, second-type separation units, and third-type separation units are arbitrarily arranged and combined, and the third-type separation unit includes a composite component composed of hydrophilic and hydrophobic components, wherein M≥1, N≥1, and L≥1.

[0036] According to a preferred embodiment of the present invention, preferably 1≤M≤100, 1≤N≤100, and 1≤L≤100.

[0037] According to a preferred embodiment of the present invention, more preferably, 1≤M≤10, 1≤N≤10, and 1≤L≤10.

[0038] In this invention, as long as the objective of this invention can be achieved, there are no special requirements for the content of hydrophilic components in the composite component. According to a preferred embodiment of this invention, the content of hydrophilic components in the composite component is 10%-90% by weight, preferably 40%-60% by weight. By adopting the aforementioned preferred scheme, the dehydration efficiency of water-containing gases can be further improved.

[0039] In this invention, the method for preparing the composite component can be a conventional method in the art. According to a preferred embodiment of this invention, the method for preparing the composite component includes mixing and filling hydrophilic and hydrophobic components; or mixing and forging hydrophilic and hydrophobic components; or mixing and weaving hydrophilic and hydrophobic components.

[0040] According to a preferred embodiment of the present invention, the method for preparing the composite component includes partially modifying the hydrophilic component to be hydrophobic to obtain the composite component.

[0041] According to a preferred embodiment of the present invention, the hydrophobic component is partially modified to be hydrophilic to obtain the composite component.

[0042] According to a preferred embodiment of the present invention, the contact element is partially modified to be hydrophilic and partially modified to be hydrophobic to obtain a composite component.

[0043] In this invention, as long as the objective of the invention is achieved, the methods for partial hydrophobic modification and partial hydrophilic modification can be conventional choices in the art. According to a preferred embodiment of the invention, the methods for partial hydrophobic modification and partial hydrophilic modification are selected from at least one of local immersion, local coating, local adsorption, local etching, local ionization, local ultraviolet irradiation, and local alkalization. By employing the aforementioned preferred solutions, the dehydration efficiency of water-containing gases can be further improved.

[0044] In this invention, the hydrophilic and hydrophobic components in the composite component are consistent with the requirements for the hydrophilic and hydrophobic components of the first type of separation unit and the second type of separation unit mentioned above, and will not be repeated here.

[0045] According to a preferred embodiment of the present invention, along the gas flow direction, the arrangement of the first type of separation unit, the second type of separation unit, and the third type of separation unit is selected from one or more combinations of the following: first type of separation unit-second type of separation unit-third type of separation unit, first type of separation unit-third type of separation unit-second type of separation unit, second type of separation unit-first type of separation unit-third type of separation unit, second type of separation unit-third type of separation unit-first type of separation unit, third type of separation unit-first type of separation unit-second type of separation unit, and third type of separation unit-second type of separation unit-first type of separation unit.

[0046] This invention provides an application of the method described in natural gas dehydration.

[0047] This invention provides a method for dehydrating natural gas, the method comprising: dehydrating natural gas according to the aforementioned dehydration method; wherein the water content of the water-containing natural gas is 0.1-50% by weight, preferably 1-25% by weight; and / or

[0048] The water-containing natural gas contains water foam.

[0049] The natural gas dehydration method of the present invention is not only simple in process, but also greatly improves the natural gas dehydration efficiency and reduces the dehydration cost.

[0050] In this invention, there are no particular requirements regarding the direction in which the hydrophilic natural gas passes through the hydrophilic component, the hydrophobic component, and the composite component. According to a preferred embodiment of this invention, the natural gas passes radially and / or axially along the hydrophilic component, the hydrophobic component, and the composite component.

[0051] According to a preferred embodiment of the present invention, the first type of contact and the second type of contact are made of ceramic filler:

[0052] Preparation of hydrophilic fillers: The ceramic fillers are initially modified with a hydrophilic modifier, and then further modified with a hydrophilic modifier.

[0053] Preparation of hydrophobic fillers: Ceramic fillers are modified using hydrophobic modifiers;

[0054] The lower layer of the packed tower is the first type of separation unit, filled with hydrophilic packing; the upper layer of the packed tower is the second type of separation unit, filled with hydrophobic packing; the middle layer of the packed tower is the third type of separation unit, filled with a mixture of hydrophilic and hydrophobic packing; water-carrying natural gas flows through the packing from bottom to top.

[0055] According to a preferred embodiment of the present invention, the first type of contact and the second type of contact are made of stainless steel mesh:

[0056] Preparation of hydrophilic metal mesh: Stainless steel metal mesh is initially modified with a hydrophilic modifier, and then further modified with a hydrophilic modifier again;

[0057] Preparation of hydrophobic metal mesh: Stainless steel metal mesh is modified with a hydrophobic modifier;

[0058] The outer layer of the filter element is a first-type separation unit, which is composed of multiple hydrophilic metal meshes stacked together; the inner layer of the filter element is a second-type separation unit, which is composed of multiple hydrophobic metal meshes stacked together; the middle layer of the filter element is a third-type separation unit, which is composed of multiple hydrophilic metal meshes and multiple hydrophobic metal meshes woven and stacked alternately.

[0059] Water-laden natural gas flows in from the inlet, where the water is intercepted by the filter element, enters the storage tank, and flows out from the drain outlet; the dehydrated natural gas enters the filter element and enters the downstream pipeline from the natural gas outlet.

[0060] According to a preferred embodiment of the present invention, in the phase separator, the surfaces of the baffles, coalescing plates and rectifiers are initially modified with a hydrophilic modifier, and then further modified with a hydrophilic modifier, forming a first type of separation unit;

[0061] For a metal mesh mist eliminator, the metal mesh is first modified to be hydrophobic: it is completely immersed in a hydrophobic modifier, and then the hydrophobic modifier is applied; then, a hydrophilic modifier is applied only to the middle part of the mist eliminator, with the hydrophilic modifier accounting for 40-60% of the middle part of the mist eliminator; the lower part of the mist eliminator is modified with a hydrophilic modifier, resulting in a mist eliminator with a metal mesh structure consisting of a second type of separation unit at the top, a third type of separation unit in the middle, and a first type of separation unit at the bottom;

[0062] Water-bearing natural gas undergoes initial dehydration through baffles, coalescing plates, and rectifiers, and then passes through a mist eliminator to obtain dehydrated natural gas.

[0063] According to a preferred embodiment of the present invention, the first type of contact and the second type of contact are made of polyester filter cloth:

[0064] Preparation of hydrophilic polyester filter cloth: The filter cloth is initially modified with a hydrophilic modifier, and then further modified with a hydrophilic modifier;

[0065] Preparation of hydrophobic polyester filter cloth: The filter cloth is modified with a hydrophobic modifier;

[0066] The filter cloth type horizontal dewatering device has a hydrophilic layer made of multiple hydrophilic polyester filter cloths woven together, serving as the first type of separation unit; a hydrophobic layer made of multiple hydrophobic polyester filter cloths woven together, serving as the second type of separation unit; and a hydrophilic-hydrophobic layer made of multiple hydrophilic polyester filter cloths and multiple hydrophobic polyester filter cloths woven together alternately, serving as the third type of separation unit.

[0067] Water-laden natural gas flows in from the dehydrator inlet, passes through the hydrophilic layer, hydrophilic-hydrophobic layer and hydrophobic layer in sequence, and the dehydrated natural gas flows out from the outlet, while the removed water is discharged through the drain valve.

[0068] According to a preferred embodiment of the present invention, the first contact and the second contact are made of cotton filter cloth:

[0069] The all-cotton filter cloth can be used directly as a hydrophilic all-cotton filter cloth.

[0070] Preparation of hydrophobic cotton filter cloth: The cotton filter cloth is modified with a hydrophobic modifier;

[0071] The filter cloth type vertical dewatering device has a hydrophilic layer made of multiple hydrophilic cotton filter cloths woven together, serving as the first type of separation unit; a hydrophobic layer made of multiple hydrophobic cotton filter cloths woven together, serving as the second type of separation unit; and a hydrophilic-hydrophobic layer made of multiple hydrophilic cotton filter cloths and multiple hydrophobic cotton filter cloths woven together alternately, serving as the third type of separation unit.

[0072] Water-laden natural gas flows in from the inlet of the lower dehydrator, passes through a hydrophilic filter cloth, a hydrophilic-hydrophobic composite filter cloth, and a hydrophobic filter cloth in sequence, and the dehydrated natural gas flows out from the upper outlet, while the removed water is discharged through the drain valve.

[0073] Specifically, according to a preferred embodiment of the present invention, for example, Figure 1 As shown, ceramic fillers are used for both the first and second type of contact components:

[0074] Preparation of hydrophilic fillers: The ceramic filler is immersed in a hydrophilic modifier such as polyvinylpyrrolidone, then removed and dried at room temperature. It is then immersed in a hydrophilic modifier such as polyvinylpyrrolidone again, and then removed and dried at room temperature.

[0075] Preparation of hydrophobic filler: Immerse the ceramic filler in a hydrophobic modifier such as perfluorosilane for 30 minutes. After immersion, air dry at room temperature.

[0076] The lower layer of the packed tower is the first type of separation unit, filled with hydrophilic packing (hydrophilic components); the upper layer is the second type of separation unit, filled with hydrophobic packing (hydrophobic components); the middle layer is the third type of separation unit, filled with a mixture of hydrophilic and hydrophobic packing. Water-laden natural gas flows from bottom to top through the packing, such as... Figure 1 As shown.

[0077] According to a preferred embodiment of the present invention, such as Figure 2 As shown,

[0078] The first and second type of contact components are made of 316 stainless steel mesh.

[0079] Preparation of hydrophilic metal mesh: 316 stainless steel mesh with a pore size of 200-500 micrometers is immersed in a hydrophilic modifier such as polyether silane. After being taken out, it is dried at room temperature. Then it is immersed in a hydrophilic modifier such as polyether silane again. After being taken out, it is dried at room temperature.

[0080] Preparation of hydrophobic metal mesh (hydrophobic component): Coat the surface of a stainless steel 316 metal mesh with a pore size of 200-500 micrometers with a hydrophobic modifier, such as a polytetrafluoroethylene film with a thickness of 20 micrometers.

[0081] The outer layer of the filter element is a first-type separation unit, which is composed of multiple layers of hydrophilic metal mesh, such as 10-30 layers (hydrophilic component); the inner layer of the filter element is a second-type separation unit, which is composed of multiple layers of hydrophobic metal mesh, such as 30-50 layers (hydrophilic component); the middle layer of the filter element is a third-type separation unit, which is composed of multiple layers of hydrophilic metal mesh, such as 20-40 layers, and multiple layers of hydrophobic metal mesh, such as 20-40 layers, woven and stacked alternately (composite component).

[0082] Water-laden natural gas flows in through the inlet; the moisture is intercepted by the filter element and enters the storage tank, flowing out through the drain outlet; the dehydrated natural gas enters the filter element and then flows into the downstream pipeline through the natural gas outlet. Figure 2 As shown.

[0083] According to a preferred embodiment of the present invention, such as Figure 3 As shown,

[0084] For baffles, coalescing plates, and rectifiers, a hydrophilic modifier, such as a layer of polyvinylpyrrolidone, is uniformly sprayed onto the surface. After drying at room temperature, two more coats are sprayed to perform hydrophilic modification, which constitutes the first type of separation unit.

[0085] For the mist eliminator (with an internal multi-layered metal mesh structure), the metal mesh is first modified to be hydrophobic: it is completely immersed in a hydrophobic modifier, such as perfluorosilane, for a certain time, for example, 20 minutes, then removed and air-dried at room temperature; then it is immersed again in a hydrophobic modifier, such as perfluorosilane, for a certain time, for example, 20 minutes, then removed and air-dried at room temperature; then a hydrophilic modifier, such as polyvinylpyrrolidone, is sprayed only on the middle part of the mist eliminator, with the sprayed portion accounting for 40-60% of the middle part of the mist eliminator. Finally, the lower part of the mist eliminator is immersed in a hydrophilic modifier, such as polyvinylpyrrolidone. This results in a mist eliminator with a second type of separation unit in the upper part of the metal mesh structure, a third type of separation unit in the middle part, and a first type of separation unit in the lower part.

[0086] Water-bearing natural gas undergoes preliminary dehydration through baffles, coalescing plates, and a rectifier, and then passes through a mist eliminator to obtain dehydrated natural gas. For example... Figure 3 As shown.

[0087] According to a preferred embodiment of the present invention, such as Figure 4 As shown,

[0088] Polyester filter cloth is used for both Class I and Class II contact components.

[0089] Preparation of hydrophilic polyester filter cloth: The filter cloth is soaked in a hydrophilic modifier such as NaOH solution, and then soaked in a hydrophilic modifier such as polyhydroxyalkyl azo solution. After removal, it is dried.

[0090] Preparation of hydrophobic polyester filter cloth: A hydrophobic modifier such as perfluorosilane is sprayed onto the surface of the filter cloth, and then dried.

[0091] The filter cloth type horizontal dewatering device has a hydrophilic layer 2 made of multiple sheets of hydrophilic polyester filter cloth, such as 100-300 or 200 sheets, as the first type of separation unit; a hydrophobic layer 4 made of multiple sheets of hydrophobic polyester filter cloth, such as 100-300 or 200 layers, as the second type of separation unit; and a hydrophilic-hydrophobic layer 3 made of alternating layers of hydrophilic polyester filter cloth, such as 100-300 or 200 sheets, as the third type of separation unit.

[0092] Water-laden natural gas flows in from the dehydrator inlet, passing sequentially through hydrophilic layer 2, hydrophilic-hydrophobic layer 3, and hydrophobic layer 4. The dehydrated natural gas flows out from the outlet, and the removed water is discharged through the drain valve. Figure 4 As shown.

[0093] According to a preferred embodiment of the present invention, such as Figure 5 As shown,

[0094] The first and second contact elements are made of pure cotton filter cloth.

[0095] All-cotton filter cloth can be used directly as hydrophilic all-cotton filter cloth.

[0096] Preparation of hydrophobic cotton filter cloth: The cotton filter cloth is soaked in a hydrophobic modifier such as perfluorosilane and then dried.

[0097] The filter cloth type vertical dewatering device has a hydrophilic layer 3, which is woven from multiple sheets of hydrophilic cotton filter cloth, such as 100-300 or 200 sheets, as the first type of separation unit; a hydrophobic layer 5, which is woven from multiple sheets of hydrophobic cotton filter cloth, such as 100-300 or 200 sheets, as the second type of separation unit; and a hydrophilic-hydrophobic layer 4, which is woven from multiple sheets of hydrophilic cotton filter cloth, such as 100-300 or 200 sheets, and multiple sheets of hydrophobic cotton filter cloth, such as 100-300 or 200 sheets, arranged alternately, as the third type of separation unit.

[0098] Water-laden natural gas flows in from the inlet of the lower dehydrator, passing sequentially through a hydrophilic filter cloth, a hydrophilic-hydrophobic composite filter cloth, and a hydrophobic filter cloth. The dehydrated natural gas flows out from the upper outlet, and the removed water is discharged through the drain valve. Figure 5 As shown.

[0099] In this invention, as long as the objective of this invention can be achieved, there are no special requirements for the driving force of the natural gas. According to a preferred embodiment of this invention, the driving force of the natural gas is selected from at least one of the upstream positive pressure, the downstream negative pressure, or the capillary force of the gas-liquid phase.

[0100] The present invention will be further described below through specific embodiments. However, the scope of the present invention is not limited to the scope covered by the embodiments.

[0101] Example 1

[0102] like Figure 1 As shown,

[0103] Ceramic fillers are used for both Class I and Class II contact components.

[0104] Preparation of hydrophilic filler: Ceramic filler with a size of about 5 mm was soaked in polyvinylpyrrolidone for 60 minutes, then removed and air-dried at room temperature. Then it was soaked in polyvinylpyrrolidone again for 60 minutes, and then removed and air-dried at room temperature.

[0105] Preparation of hydrophobic filler: Ceramic filler with a size of about 5 mm was immersed in perfluorosilane for 30 minutes. After being removed, it was air-dried at room temperature.

[0106] The lower layer of the packed tower is the first type of separation unit, which is filled with hydrophilic packing for 0.5 meters (hydrophilic component); the upper layer of the packed tower is the second type of separation unit, which is filled with hydrophobic packing for 1 meter (hydrophobic component); the middle layer of the packed tower is the third type of separation unit, which is filled with a mixed packing of hydrophilic and hydrophobic packing for 1 meter, with the hydrophobic packing content in the mixed packing being 60wt%.

[0107] Natural gas carrying 10% by weight of water flows upward through the packing material, such as... Figure 1 As shown.

[0108] This method can produce 2 million cubic meters of dehydrated natural gas per day and 800 cubic meters of water per day.

[0109] Example 2

[0110] like Figure 2 As shown,

[0111] The first and second type of contact components are made of 316 stainless steel mesh.

[0112] Preparation of hydrophilic metal mesh: Stainless steel 316 metal mesh with a pore size of 200-500 micrometers and a thickness of 0.5 cm is immersed in polyether silane for 60 minutes, taken out and dried at room temperature, and then immersed in polyether silane again for 60 minutes, taken out and dried at room temperature.

[0113] Preparation of hydrophobic metal mesh (hydrophobic component): A 20-micron thick polytetrafluoroethylene film is coated on the surface of a 316 stainless steel metal mesh with a pore size of 200-500 micrometers and a thickness of 0.5 cm.

[0114] The outer layer of the filter element is the first type of separation unit, which is composed of 20 hydrophilic metal meshes stacked together (hydrophilic component); the inner layer of the filter element is the second type of separation unit, which is composed of 40 hydrophobic metal meshes stacked together (hydrophilic component); the middle layer of the filter element is the third type of separation unit, which is composed of 30 hydrophilic metal meshes and 30 hydrophobic metal meshes woven and stacked alternately (composite component, with hydrophobic metal mesh accounting for 50%).

[0115] Natural gas carrying 20% ​​water by weight flows in through the inlet. The water is intercepted by the filter element, enters the storage tank, and flows out through the drain outlet. The dehydrated natural gas enters the filter element and then flows into the downstream pipeline through the natural gas outlet. Figure 2 As shown.

[0116] This method can produce 2 million cubic meters of dehydrated natural gas per day and 1,000 cubic meters of water per day.

[0117] Example 3

[0118] like Figure 3 As shown,

[0119] In this embodiment, spraying and immersion are used as examples to modify components in an existing phase separator.

[0120] For baffles, coalescing plates, and rectifiers, a layer of polyvinylpyrrolidone is uniformly sprayed onto the surface, dried at room temperature, and then sprayed twice more to perform hydrophilic modification, which constitutes the first type of separation unit.

[0121] For the mist eliminator (with an internal multi-layered metal mesh structure), the metal mesh is first modified to be hydrophobic: it is completely immersed in perfluorosilane for 20 minutes, then removed and air-dried at room temperature; then it is immersed again in perfluorosilane for 20 minutes, removed and air-dried at room temperature; then polyvinylpyrrolidone (PVP) is sprayed only in the middle part of the mist eliminator, with the sprayed portion accounting for 60% of the middle part of the mist eliminator. Finally, PPVP is introduced into the lower part of the mist eliminator. This results in a mist eliminator with a second-type separation unit in the upper part, a third-type separation unit in the middle, and a first-type separation unit in the lower part of the metal mesh structure.

[0122] Natural gas carrying 15% water by weight undergoes preliminary dehydration via baffles, coalescing plates, and a rectifier, followed by a mist eliminator to obtain dehydrated natural gas. For example... Figure 3 As shown.

[0123] This method yields 2 million cubic meters of dehydrated natural gas per day and 700 cubic meters of water per day.

[0124] Example 4

[0125] like Figure 4 As shown,

[0126] Polyester filter cloth is used for both Class I and Class II contact components.

[0127] Preparation of hydrophilic polyester filter cloth: The filter cloth was soaked in 10% NaOH solution at 80℃ for 1 hour, then soaked in 10% polyhydroxyalkyl azo solution for 1 hour, and then dried at 50℃ for 4 hours.

[0128] Preparation of hydrophobic polyester filter cloth: Perfluorosilane is sprayed onto the surface of the filter cloth and then dried at 30°C for 4 hours.

[0129] The filter cloth type horizontal dewatering device has a hydrophilic layer 2 made of 200 layers of hydrophilic polyester filter cloth as the first type of separation unit; a hydrophobic layer 4 made of 200 layers of hydrophobic polyester filter cloth as the second type of separation unit; and a hydrophilic-hydrophobic layer 3 made of alternating layers of 200 layers of hydrophilic polyester filter cloth and 200 layers of hydrophobic polyester filter cloth as the third type of separation unit.

[0130] Natural gas carrying 15% by weight of water flows into the dehydrator inlet, passing sequentially through hydrophilic layer 2, hydrophilic-hydrophobic layer 3, and hydrophobic layer 4. The dehydrated natural gas flows out from the outlet, and the removed water is discharged through the drain valve. Figure 4 As shown.

[0131] This method yields 2 million cubic meters of dehydrated natural gas per day and 900 cubic meters of water per day.

[0132] Example 5

[0133] like Figure 5 As shown,

[0134] The first and second contact elements are made of pure cotton filter cloth.

[0135] All-cotton filter cloth can be used directly as hydrophilic all-cotton filter cloth.

[0136] Preparation of hydrophobic cotton filter cloth: The cotton filter cloth was soaked in perfluorosilane for 4 hours, and then dried in a ventilated environment at 30°C for 24 hours.

[0137] The filter cloth type vertical dewatering device has a hydrophilic layer 3 made of 200 layers of hydrophilic cotton filter cloth, which serves as the first type of separation unit; a hydrophobic layer 5 made of 200 layers of hydrophobic cotton filter cloth, which serves as the second type of separation unit; and a hydrophilic-hydrophobic layer 4 made of alternating layers of 200 layers of hydrophilic cotton filter cloth and 200 layers of hydrophobic cotton filter cloth, which serves as the third type of separation unit.

[0138] Natural gas carrying 25% water by weight flows in from the inlet of the lower dehydrator, passing sequentially through a hydrophilic filter cloth, a hydrophilic-hydrophobic composite filter cloth, and a hydrophobic filter cloth. The dehydrated natural gas flows out from the upper outlet, and the removed water is discharged through the drain valve. Figure 5 As shown.

[0139] This method yields 2 million cubic meters of dehydrated natural gas per day and 800 cubic meters of water per day.

[0140] Example 6

[0141] Similar to Example 1, the difference is that the packed tower does not have a third type of separation unit, but only two layers, namely an upper layer (second type of separation unit) formed by 1.5 meters of hydrophobic packing and a lower layer (first type of separation unit) formed by 1.0 meter of hydrophilic packing.

[0142] This method yields 1 million cubic meters of dehydrated natural gas per day and 400 cubic meters of water per day.

[0143] Example 7

[0144] Same as Example 1, except that:

[0145] Preparation of hydrophilic filler: Ceramic filler with a size of about 0.5 mm is coated with hydrophilic paint and dried at room temperature.

[0146] Preparation of hydrophobic filler: Ceramic filler with a size of about 0.5 mm is coated with hydrophobic paint and dried at room temperature.

[0147] This method yields 1.2 million cubic meters of dehydrated natural gas per day and 600 cubic meters of water per day.

[0148] Comparative Example 1

[0149] Existing triethylene glycol (TED) natural gas dehydration processes cannot handle gases with high water content. When the water content exceeds 10%, dehydration efficiency deteriorates, TED can not be regenerated in a timely manner, regeneration energy consumption is high, and large amounts of salt crystals are generated, damaging equipment. Furthermore, water foam entering the TED tower can generate foam inside the drying tower, causing accidents such as tower tipping.

[0150] Comparative Example 2

[0151] Same as Example 1, but the material is not modified. Only a small amount of water condenses on the filler and is then removed from the natural gas by gravity, while a large amount of water remains in the natural gas. Especially in the presence of water foam, the unmodified filler promotes the formation of fine foam, making the foam more stable and unable to remove water from it.

[0152] In summary, the method of the present invention can effectively remove a large amount of water from natural gas, and can also effectively remove water carried in foam, thus avoiding the impact of foam on subsequent processing.

[0153] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for dehydrating natural gas, characterized in that, The method includes feeding natural gas into M first-class separation units, N second-class separation units, and L third-class separation units; wherein, M≥1, N≥1, and L≥1; The natural gas has a water content of 1-25% by weight; the natural gas contains water foam; The first type of separation unit is a hydrophilic component; the second type of separation unit is a hydrophobic component; and the third type of separation unit is a composite component composed of hydrophilic and hydrophobic components; the content of the hydrophilic component in the composite component is 40%-60% by weight. Along the gas flow direction, the arrangement of the first type of separation unit, the second type of separation unit, and the third type of separation unit is: first type of separation unit - third type of separation unit - second type of separation unit.

2. The method according to claim 1, wherein, 1≤M≤100, 1≤N≤100.

3. The method according to claim 2, wherein, 1≤M≤10, 1≤N≤10.

4. The method according to claim 3, wherein, The natural gas has a water content of 10-25% by weight.

5. The method according to claim 1, wherein, The hydrophilic component is provided with through holes, with a porosity of 20%-90%; and / or The hydrophilic component is a first-type contact component modified with a hydrophilic modifier.

6. The method according to claim 5, wherein, The porosity is 30%-60%; and / or The hydrophilic modifier is selected from at least one of hydrophilic polymers, hydrophilic dyes, hydrophilic silanes, polyether nonionic surfactants, metal oxides, quaternary ammonium compounds, nanoparticles grafted with ionic groups, nanoparticles grafted with hydroxyl groups, and hydrophilic paints.

7. The method according to claim 6, wherein, The hydrophilic modifier is selected from proteins and / or cellulose.

8. The method according to claim 6, wherein, The hydrophilic modifier is at least one of hydrophilic polymers, hydrophilic dyes, and hydrophilic silanes.

9. The method according to claim 6, wherein, The hydrophilic modifier is at least one of polyvinylpyrrolidone, polyhydroxyalkyl azo, and polyether silane.

10. The method according to claim 1, wherein, The hydrophobic component is provided with through holes, and the porosity is 20%-90%; and / or The hydrophobic component is a type II contact component modified with a hydrophobic modifier.

11. The method according to claim 10, wherein, The porosity is 30%-60%; and / or The hydrophobic modifier is selected from at least one of fluorinated silane chemicals, hydrophobic polymers, fluorinated surfactants, alkyl-grafted nanoparticles, aromatic hydrocarbon-grafted nanoparticles, and oleophilic paints.

12. The method according to claim 11, wherein, The hydrophobic modifier is a fluorinated silane chemical agent and / or a hydrophobic polymer.

13. The method according to claim 12, wherein, The hydrophobic modifier is a perfluorosilane and / or polytetrafluoroethylene.

14. The method according to any one of claims 5-9, wherein, The first type of contact element is selected from one or more of baffles, coalescing plates, rectifiers, packing, trays, and filters.

15. The method according to any one of claims 10-13, wherein, The second type of contact element is selected from one or more of the following: baffles, coalescing plates, rectifiers, packing, trays, and filters.

16. The method of claim 14, wherein, The forming materials of the first type of contact are each selected from one or more of metal, ceramic, glass, cotton fiber, polyamide fiber, polyester fiber and wood.

17. The method according to claim 15, wherein, The material used to form the second type of contact is selected from one or more of the following: metal, ceramic, glass, cotton fiber, polyamide fiber, polyester fiber, and wood.

18. The method according to any one of claims 5-13, wherein, The modification method is selected from one or both of chemical and physical methods.

19. The method according to claim 18, wherein, The modification method is at least one of soaking, coating, adsorption and etching.

20. The method according to claim 1, wherein, 1≤M≤100, 1≤N≤100, 1≤L≤100.

21. The method according to claim 20, wherein, 1≤M≤10, 1≤N≤10, 1≤L≤10.

22. The method according to claim 1, wherein, The method for preparing the composite component includes: mixing and filling hydrophilic and hydrophobic components; or forging a mixture of hydrophilic and hydrophobic components; or weaving a mixture of hydrophilic and hydrophobic components; or weaving a mixture of hydrophilic and hydrophobic components; or The hydrophilic component is partially modified to be hydrophobic to obtain a composite component; or The hydrophobic component is partially modified to be hydrophilic to obtain a composite component; or Composite components are obtained by partially modifying the contact parts to be hydrophilic and partially hydrophobic. The methods for partial hydrophobic modification and partial hydrophilic modification are selected from at least one of local immersion, local coating, local adsorption, local etching, local ionization, local ultraviolet irradiation, and local alkalization.

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