A filtering device for deep dehydration and deacidification of natural gas

Abstract

The present invention discloses a filtering device for deep dehydration and deacidification of natural gas, which belongs to the technical field of natural gas filtering and processing. The device comprises a filter chamber, a first air inlet pipe, a second air inlet pipe, an air outlet pipe and a recovery air pipe. Natural gas is introduced into the filter chamber through the first air inlet pipe, and a filter is arranged in the filter chamber. A filter element in the filter realizes the coordinated chemical adsorption and physical adsorption through a porous filter element and loaded polyethylene polyamine, thereby realizing deep filtration and removal of impurity gases in the natural gas, realizing deep dehydration and deacidification of the natural gas, and discharging the filtered natural gas through the air outlet pipe, thereby reducing the corrosion of storage equipment by LNG in the later stage. At the same time, a heating component is arranged on the second air inlet pipe, so that heated inert gas is introduced to analyze the filter element, and the analyzed gas is discharged through the recovery air pipe, thereby realizing the recycling of the filter.

Description

Technical Field

[0001] The present invention belongs to the technical field of natural gas filtering and processing, and in particular relates to a filtering device for deep dehydration and deacidification of natural gas. Background Art

[0002] As a clean energy, the production, storage and transportation technology of liquefied natural gas (LNG) has become an important research direction in the energy field. In the conventional LNG production process, the raw natural gas needs to be pre-treated by dehydration and deacidification and meet the national transportation and storage quality standards (the natural gas quality standard is that the moisture content is ≤102mg / m 3 , carbon dioxide content ≤3.0%, hydrogen sulfide ≤6mg / m 3 ) and then stored in liquid form through low-temperature liquefaction (-162°C).

[0003] Natural gas that meets national quality standards is dehydrated and deacidified, then pressurized and cooled to form LNG. However, LNG still contains trace amounts of water and acidic substances (H2S, CO2, etc.), which will still slowly corrode pipelines, storage tanks and other facilities. Summary of the Invention

[0004] In response to one or more of the above-mentioned defects or improvement needs in the prior art, the present invention provides a filtering device for deep dehydration and deacidification of natural gas, which can achieve deep dehydration and deacidification of natural gas that has been pretreated and meets national quality standards, further remove trace moisture, carbon dioxide, and hydrogen sulfide contained in the natural gas, and reduce the subsequent corrosion of LNG to pipelines and storage facilities.

[0005] To achieve the above-mentioned object, the present invention provides a filtering device for deep dehydration and deacidification of natural gas, which comprises a filtering chamber, a first air inlet pipe, a second air inlet pipe, an air outlet pipe and a recovery air pipe;

[0006] The filter chamber includes an air inlet end, an air outlet end and a filter, wherein the air inlet end and the air outlet end are separated by the filter; the filter includes a plurality of filter elements, and the filter element includes a porous filter element and polyethylene polyamine and a polyethylene polyamine activator loaded on the porous filter element;

[0007] The first air inlet pipe is in communication with the air inlet end of the filter chamber;

[0008] The air outlet pipe is connected to the air outlet end of the filter chamber;

[0009] The second air inlet pipe is in communication with the filter chamber, and a heating assembly is provided on the second air inlet pipe;

[0010] The recovery air pipe is in communication with the filter chamber;

[0011] During filtration, natural gas enters the filter chamber through the first air inlet pipe, the filter in the filter chamber deeply filters the natural gas to remove impurities in the natural gas, and the filtered natural gas is discharged through the air outlet pipe;

[0012] During analysis, inert gas is introduced into the second air inlet pipe, and the inert gas is heated to the analysis temperature by the heating component and then introduced into the filter chamber to heat and analyze the filter element. The inert gas and the analyzed impurity gas are discharged through the recovery air pipe.

[0013] As a further improvement of the present invention, the filter element is prepared by the following steps:

[0014] (1) The adsorption material is mixed with water, dried and formed, and then calcined to form a porous filter element;

[0015] (2) Inert gas containing hydrofluoric acid is passed into the porous filter element by vapor phase etching;

[0016] (3) Soak the porous filter element in an organic solvent containing polyethylene polyamine activator until it is completely soaked;

[0017] (4) An organic solvent containing polyethylene polyamine is sprayed into an inert gas at a certain temperature as a vapor deposition gas source, and the polyethylene polyamine is loaded into a porous filter element by vapor deposition, and the organic solvent is removed to obtain a filter element that can be deeply dehydrated and deacidified.

[0018] As a further improvement of the present invention, the polyethylene polyamine is a modified polyethylene polyamine obtained by modifying polyethylene polyamine with ethylene oxide, and the modification method includes:

[0019] (a) mixing polyethylene polyamine with an organic solvent containing 0.5-1% sodium hydroxide to form a mixed solution;

[0020] (b) mixing ethylene oxide with an inert gas to obtain a mixed gas;

[0021] (c) introducing a mixed gas at 140-160° C. into the mixed solution to stir, mix, and react;

[0022] (d) filtering the solution after the reaction, and removing the organic solvent in the solution by water bath distillation to obtain modified polyethylene polyamine;

[0023] and / or,

[0024] In step (4), the vapor deposition gas source is first atomized and homogenized by ultrasound, and the ultrasonic generator is directed toward the porous filter element to transmit the ultrasonic wave to the porous filter element, and the process continues throughout the entire loading process.

[0025] As a further improvement of the present invention, the filter chamber has a plurality of filter areas sequentially arranged from the air inlet end to the air outlet end, and the filter is arranged in each filter area to perform multi-stage filtration on the incoming natural gas.

[0026] As a further improvement of the present invention, a primary filtration area and a secondary filtration area are sequentially arranged in the filter chamber along the direction from the air inlet end to the air outlet end.

[0027] As a further improvement of the present invention, a spray assembly is further provided in the filter chamber, the spray assembly is connected to the second air inlet pipe, and at least one spray head is provided corresponding to each filter element.

[0028] As a further improvement of the present invention, an air distribution duct is provided in the filter chamber, the air distribution duct is connected to the first air inlet pipe, and at least one air outlet is provided on the air distribution duct corresponding to each filter element.

[0029] As a further improvement of the present invention, the first air inlet pipe is provided with a pressure indicator, a temperature indicator and a first analysis indicator to detect the pressure, temperature and component content of the incoming natural gas; and / or,

[0030] A pressure differential detection meter is provided corresponding to the filter chamber to detect the pressure differential in the filter chamber; and / or,

[0031] The gas outlet pipe is provided with a second analysis indicator to detect the content of components in the filtered natural gas; and / or,

[0032] The second air inlet pipe and the air recovery pipe are respectively provided with valves to control the entry of gas.

[0033] As a further improvement of the present invention, the end of the recovery air pipe facing away from the filter chamber is connected to the regeneration waste gas treatment device, and the regeneration waste gas treatment device regenerates the inert gas introduced into the filter chamber and the analyzed impurity gas, wherein the regenerated inert gas can be circulated into the second air inlet pipe as a gas source.

[0034] As a further improvement of the present invention, the filter element is a cylindrical structure with one end open, the open end of the filter element is connected to the air inlet end of the filter chamber, and mesh frames are fixedly arranged on the inner and outer sides of the filter element respectively.

[0035] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0036] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0037] (1) The filtering device for deep dehydration and deacidification of natural gas of the present invention is provided with a filter chamber and a filter in the filter chamber. The filter element in the filter realizes the coordinated chemical adsorption and physical adsorption through the porous filter element and the loaded polyethylene polyamine, thereby achieving deep filtration and removal of impurity gases in natural gas, reducing the corrosion of LNG to storage equipment in the later stage; at the same time, a heating component is provided on the second air inlet pipe to analyze the filter element by introducing heated inert gas, and the analyzed gas is discharged through the recovery air pipe, thereby realizing the recycling of the filter.

[0038] (2) The filtering device for deep dehydration and deacidification of natural gas of the present invention performs multi-stage filtration on natural gas by sequentially arranging multiple filtration zones in the filtration chamber, thereby ensuring the filtration effect and filtration accuracy of natural gas filtration; the contact area between the filter element and natural gas is increased by arranging the filter element as a cylindrical structure with one end open, thereby improving the filtration efficiency; and the waste gas generated during the filtration and analysis process is recycled and reused by connecting the recovery gas pipe to the regeneration waste gas treatment device, thereby saving production costs.

[0039] (3) The filtering device for deep dehydration and deacidification of natural gas of the present invention has a simple structure and is easy to operate. It can effectively filter out impurity gases such as moisture, carbon dioxide, and hydrogen sulfide in natural gas, thereby achieving deep dehydration and deacidification of natural gas. It has good application prospects and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. 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 these drawings without creative work.

[0041] Figure 1 This is a schematic diagram of the overall structure of a filtering device for deep dehydration and deacidification of natural gas according to an embodiment of the present invention;

[0042] Figure 2 2 is a schematic structural diagram of a filter element according to an embodiment of the present invention;

[0043] Figure 3 Schematic diagram of the arrangement of the ultrasonic generator in an embodiment of the present invention.

[0044] In all the drawings, the same reference numerals represent the same technical features, specifically: 1. first air inlet pipe; 2. second air inlet pipe; 3. recovery air pipe; 4. air outlet pipe; 5. filter chamber; 501. air inlet end; 502. air outlet end; 503. primary filtration area; 504. secondary filtration area; 505. filter; 5051. filter element; 5052. skeleton; 506. spray assembly; 507. air distribution pipeline; 6. pressure indicator; 7. temperature indicator; 8. first analysis indicator; 9. second analysis indicator; 10. first pressure difference detection gauge; 11. second pressure difference detection gauge; 12. first valve; 13. second valve; 14. nitrogen generator; 15. heating assembly; 16. regeneration waste gas treatment device; 17. natural gas downstream processing device; 18. gas deposition gas source; 19. gas phase installation pipeline; 20. ultrasonic generator; 21. power supply. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0046] In the description of the present invention, it should be understood that, unless otherwise expressly specified and limited, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0047] Furthermore, unless otherwise expressly specified or limited, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly specified or limited.

[0048] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0049] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0050] Example:

[0051] See also Figures 1 to 3 The filtering device for deep dehydration and deacidification of natural gas in a preferred embodiment of the present invention includes a filter chamber 5, a first air inlet pipe 1, a second air inlet pipe 2, an air outlet pipe 4 and a recovery air pipe 3, so as to deeply dehydrate and deacidify the natural gas that has undergone dehydration and deacidification pretreatment.

[0052] Specifically, if Figure 1 As shown in the figure, the filter chamber 5 in the preferred embodiment includes an air inlet end 501, an air outlet end 502 and a filter 505, and the air inlet end 501 and the air outlet end 502 are separated by the filter 505, so that natural gas enters the filter chamber 5 from the air inlet end 501, is filtered by the filter 505, and is output from the air outlet end 502.

[0053] More specifically, at least one filter element 5051 is provided in the filter 505 of the present invention. The filter element 5051 includes a porous filter element and polyethylene polyamine and a polyethylene polyamine activator loaded on the porous filter element, so as to chemically adsorb the impurity gas through the reaction of polyethylene polyamine with water, carbon dioxide, hydrogen sulfide, etc. in natural gas, and assist physical adsorption through the porous filter element. Through the synergy of chemical adsorption and physical adsorption, deep adsorption of impurity gas is achieved.

[0054] like Figure 2As shown in the figure, the filter element 5051 is set as a cylindrical structure with one end open. The open end of the filter element 5051 is connected to the air inlet end 501 of the filter chamber 5. Natural gas enters the filter chamber 5 through the air inlet end 501 and enters the filter element 5051 from the open end of the filter element 5051. After being filtered, it is discharged from the pores of the filter element 5051, so as to increase the contact area between the natural gas and the filter element 5051.

[0055] Of course, the filter element 5051 can also be made into other forms, depending on the actual setting requirements.

[0056] Further preferably, a stainless steel mesh skeleton 5052 is fixedly provided on the inner and outer sides of the filter element 5051 respectively, so as to support the filter element 5051 through the skeleton 5052 and reduce the base material powder of the filter element 5051 from entering the filter chamber 5 and the pipeline through the skeleton 5052.

[0057] At the same time, a stainless steel filter element may be nested in the outer layer of the filter element 5051 to control the filtration accuracy by controlling the stainless steel filter element. The filtration accuracy of the stainless steel filter element may be 0.1~5μm.

[0058] Preferably, multiple filter areas are arranged in sequence in the filter chamber 5 from the air inlet end 501 to the air outlet end 502, and filters 505 are arranged in each filter area. It is further preferred that the filtration accuracy of the multiple filter areas increases in sequence from the air inlet end 501 to the air outlet end 502, so as to perform multi-stage filtration on the natural gas introduced.

[0059] like Figure 1 In the specific embodiment shown in , a primary filter area 503 and a secondary filter area 504 are sequentially arranged in the filter chamber 5 along the direction from the air inlet end 501 to the air outlet end 502, wherein the filtration accuracy of the primary filter area 503 is 5 μm, and the filtration accuracy of the secondary filter area 504 is 0.1 μm. While filtering the impurity gas of the natural gas, the secondary filter area 504 can also remove the trace dust generated by the filter element 5051 itself.

[0060] Preferably, a pressure differential detection meter is further provided for the corresponding filter chamber 5, and further preferably, a pressure differential detection meter is provided for each filter zone in the corresponding filter chamber 5, such as Figure 1 As shown in the figure, a first pressure difference detection gauge 10 and a second pressure difference detection gauge 11 are respectively provided corresponding to the primary filtration area 503 and the secondary filtration area 504, and the two ends of each pressure difference detection gauge correspond to the two sides of the filter 505 to detect the pressure difference between before and after filtration in each filtration area.

[0061] Furthermore, the first air inlet pipe 1 is connected to the air inlet end 501 of the filter chamber 5 , and its end facing away from the filter chamber 5 can be connected to a natural gas source that has been pre-treated by dehydration and deacidification, so as to introduce natural gas to be deeply filtered into the filter chamber 5 .

[0062] Preferably, an air distribution pipe 507 is further provided in the filter chamber 5 , which is connected to the first air inlet pipe 1 , and at least one air outlet is provided on the air inlet pipe corresponding to each filter element 5051 to evenly pass natural gas into multiple filter elements 5051 .

[0063] Preferably, a pressure indicator 6, a temperature indicator 7 and a first analysis indicator 8 are provided on the first air inlet pipe 1 to detect the pressure, temperature and component content of the incoming natural gas respectively.

[0064] Furthermore, the gas outlet pipe 4 is connected to the gas outlet end 502 of the filter chamber 5 to discharge the filtered natural gas through the gas outlet pipe 4; the other end of the gas outlet pipe 4 can be connected to the storage device, or directly connected to the natural gas downstream processing device 17 to directly pass the natural gas into the natural gas downstream processing device 17 for further processing.

[0065] Preferably, a second analysis indicator 9 is provided on the gas outlet pipe 4 to detect the content of components in the filtered natural gas.

[0066] Furthermore, the second air inlet pipe 2 is connected to the filter chamber 5, and the end thereof facing away from the filter chamber 5 can be connected to an inert gas source, such as a nitrogen generator 14, so as to introduce inert gas into the filter chamber 5 through the second air inlet pipe 2; at the same time, a heating component 15 is provided on the second air inlet pipe 2 to heat the inert gas, and the heating temperature is 120~135°C, and then the filter element 5051 after absorption saturation is heated and analyzed by the high-temperature inert gas, so that the filter element 5051 can be recycled.

[0067] Preferably, a spray assembly 506 is further provided in the filter chamber 5, which is connected to the second air inlet pipe 2, and at least one nozzle is provided corresponding to each filter element 5051, so as to evenly spray the inert gas heated to a certain temperature on each filter element 5051, and evenly heat the filter element 5051 to speed up the parsing rate while avoiding the waste of resources caused by the fact that some filter elements 5051 have been fully parsed while some filter elements 5051 have not been completely parsed and need to continue ventilation.

[0068] Preferably, a first valve 12 is provided on the second air intake pipe 2 to control the opening and closing of the second air intake pipe 2 .

[0069] Furthermore, the recycle gas pipe 3 is connected to the filter chamber 5 to discharge the inert gas and the extracted impurity gases after desorption. Preferably, the end of the recycle gas pipe 3 facing away from the filter chamber 5 is connected to the regeneration waste gas treatment device 16, so that the impurity gases extracted by the inert gas machine can be regenerated by the regeneration waste gas treatment device 16. The regenerated inert gas can be circulated into the second air inlet pipe 2 as a gas source to save filtration costs.

[0070] Preferably, a second valve 13 is provided on the recovery air pipe 3 to control the opening and closing of the recovery air pipe 3 .

[0071] It is understood that the above device can achieve deep filtration of natural gas while also analyzing the filter element 5051 for recycling. The process specifically includes:

[0072] During filtration, natural gas enters the filter chamber 5 through the first air inlet pipe 1. The filter 505 in the filter chamber 5 deeply filters the natural gas to remove impurities in the natural gas, and then discharges the filtered natural gas through the air outlet pipe 4.

[0073] When the filter element 5051 is saturated with absorption, without introducing natural gas, open the first valve 12 and the second valve 13, introduce nitrogen into the second air inlet pipe 2, and heat the nitrogen to the decomposition temperature of the filter element 5051 through the heating component 15 and then introduce it into the filter chamber 5, and spray the heated nitrogen on each filter element 5051 through the spray component 506. The filter element 5051 will decompose and discharge the absorbed impurity gas due to the heat, and discharge the nitrogen and the decomposed impurity gas in the filter chamber 5 through the recovery air pipe 3, and the waste gas will be recovered by the crystal regeneration waste gas treatment device 16. The recovered nitrogen can be introduced into the filter chamber 5 again through the second air inlet pipe 2 for decomposition when it needs to be decomposed next time, so as to achieve the effect of recycling.

[0074] It can be known that before the filter element 5051 is officially used, the adsorbable amount of the filter element 5051 can be tested in advance, so that when it is officially put into use, the filter element 5051 can be analyzed regularly according to the adsorbable amount.

[0075] Furthermore, the filter element 5051 of the present invention is prepared by the following preparation method:

[0076] (1) The adsorption material is mixed with water, dried and formed, and then calcined to form a porous filter element;

[0077] Preferably, the decomposition temperature of the adsorption substrate does not exceed 150°C, such as magnesium oxide, to ensure that when the filter element 5051 is decomposed by heating, the polyethylene polyamine will not undergo a decomposition reaction, thereby avoiding the failure of the polyethylene polyamine and ensuring the chemical stability of the polyethylene polyamine.

[0078] Preferably, magnesium oxide is used as the adsorbent material, and aluminum silicate and sodium silicate are added to the magnesium oxide to enhance the adsorbent's adhesive properties. In a specific embodiment of the present invention, the weight proportions of the components are: 100 parts magnesium oxide, 3-5 parts aluminum silicate, and 3-5 parts sodium silicate. Furthermore, preferably, 10-15 parts 0.1 mm glass fiber are added to the magnesium oxide to further enhance the strength of the porous filter element.

[0079] (2) The inert gas containing corrosive gas is passed into the porous filter element through the gas phase corrosion method.

[0080] In a preferred embodiment, nitrogen containing 0.5-1% hydrofluoric acid is introduced into the calcined porous filter element by a vapor phase etching method to further increase the porosity of the porous filter element.

[0081] It is known that, while aluminum silicate and sodium silicate serve as the adsorption material binder in the previous step, during vapor phase etching, the corrosive gas simultaneously corrodes the aluminum silicate and sodium silicate while corroding the magnesium oxide, further increasing the porosity of the porous filter element and, in turn, the surface area available for polyethylene polyamine attachment. Preferably, the porous filter element has a pore diameter of approximately 10 μm, and in a normal distribution curve of all pore diameters within the porous filter element, the proportion of pores smaller than 10 μm exceeds 80%.

[0082] In another specific embodiment of the present invention, in step (1), 10 to 15 parts of nano sodium fluoride or potassium fluoride are added to 100 parts of the adsorption material, and in step (2), hydrochloric acid is used as an etchant to slowly corrode the fluoride, thereby generating micropores on the filter element, thereby increasing the loadable area of the porous filter element.

[0083] The corrosion products formed after gas phase corrosion are loosely attached to the porous filter element. The porous filter element can be rinsed with deionized water and ultrasonic oscillation can be used to remove the corrosion products attached to the porous filter element. After removal, the porous filter element is calcined and dehydrated at a high temperature of 800~900℃.

[0084] (3) Soaking the porous filter element in an organic solvent containing a polyethylene polyamine activator until it is completely soaked, so as to load the polyethylene polyamine activator into the porous filter element, thereby increasing the chemical activity of the polyethylene polyamine during filtration, and thereby increasing the absorption efficiency of carbon dioxide, hydrogen sulfide and water; in the organic solvent containing the polyethylene polyamine activator, the content of the polyethylene polyamine activator is preferably 5-15%, and the preferred polyethylene polyamine activator is piperazine.

[0085] (4) An organic solvent containing polyethylene polyamine is sprayed into an inert gas at a certain temperature as a vapor deposition gas source 18, and the polyethylene polyamine is loaded into a porous filter element by vapor deposition, and the organic solvent is removed to obtain a filter element 5051 that can be deeply dehydrated and deacidified.

[0086] It is understandable that pure polyethylene polyamine solution is viscous and cannot penetrate into the pores of the porous filter element. Therefore, it is first diluted with an organic solvent and loaded onto an inert gas. Then, the polyethylene polyamine molecules are dispersed to the pore surface using the inert gas through vapor deposition, so that the polyethylene polyamine is attached more evenly in the pores, with a deeper attachment depth and a larger attachment amount.

[0087] At the same time, due to the high viscosity and molecular weight of polyethylene polyamine, high temperatures during use may cause polyethylene polyamine to melt. If too much polyethylene polyamine is loaded on the porous filter element, it may easily lead to pore blockage. Therefore, the polyethylene polyamine content in the filter element 5051 is preferably 10~20%, and the principle of appropriate loading and multiple analysis should be adopted during use.

[0088] Preferably, an anhydrous ethanol solution containing 0.3-0.5% polyethylene polyamine is sprayed into nitrogen at 75-90° C. to obtain the vapor deposition gas source 18 .

[0089] Since the polyethylene polyamine activator loaded on the porous filter element may be blown off during vapor deposition, it is preferred that when preparing the vapor deposition gas source 18, an organic solvent containing polyethylene polyamine is sprayed into the inert gas, and an organic solvent containing the polyethylene polyamine activator is also sprayed into the inert gas to form the vapor deposition gas source 18. It is further preferred that the molar ratio of polyethylene polyamine to the polyethylene polyamine activator in the vapor deposition gas source 18 is 1: (2~4) to supplement the polyethylene polyamine activator.

[0090] Preferably, in order to better load the active polyethylene polyamine and make it adhere more evenly and densely to the porous filter element, it is preferred to prepare the vapor deposition gas source 18 and then use an ultrasonic generator 20 to atomize and homogenize the vapor deposition gas source 18 through ultrasonic waves, so as to increase the movement rate and energy of various molecules through ultrasonic waves, so that during vapor deposition, although the molecules are intercepted when passing through the filter element material, they are still diffusing.

[0091] At the same time, the ultrasonic generator 20 is set directly opposite the porous filter element to transmit ultrasonic waves in the direction of the porous filter element so that the ultrasonic waves can continue to act on the porous filter element and continue throughout the entire loading process, thereby coordinating the polyethylene polyamine loaded on the porous filter element and the polyethylene polyamine activator to be fully mixed and activated, thereby further improving the adsorption activity of the polyethylene polyamine.

[0092] like Figure 3As shown in , during actual preparation, a gas phase installation pipe 19 can be provided, an ultrasonic generator 20 can be provided in the gas phase installation pipe 19, and a power supply 21 is provided corresponding to the ultrasonic generator 20 to control the opening and closing of the ultrasonic generator 20. During vapor deposition, a vapor deposition gas source 18 formed by nitrogen loaded with a polyethylene polyamine ethanol solution is input into the gas phase installation pipe 19, and the vapor deposition gas source 18 is atomized and homogenized by ultrasonic waves. The atomized and homogenized vapor deposition gas source 18 is then passed into a porous filter element for deposition. During the deposition process, ultrasonic waves are continuously emitted to the porous filter element by the ultrasonic generator 20.

[0093] It should be noted that the ultrasonic wave should use a low frequency to prevent the filter element from being damaged by excessive frequency.

[0094] Preferably, in order to further increase the thermal stability of polyethylene polyamine, reduce the decomposition of polyethylene polyamine during desorption heating, and increase the absorption-desorption times of the active material in the filter element, the polyethylene polyamine is further modified, and the specific method is as follows:

[0095] (a) Polyethylene polyamine is mixed with an organic solvent containing 0.5-1% sodium hydroxide to form a mixed solution, wherein the sodium hydroxide acts as a catalyst; the organic solvent may be methanol, ethanol, etc.;

[0096] (b) mixing ethylene oxide with nitrogen and controlling the gas temperature at 120-135°C;

[0097] (c) The mixed gas at 140-160° C. in step (b) is introduced into the mixed solution in step (2.1) and stirred and mixed. Polyethylene polyamine reacts with ethylene oxide according to the reaction formula:

[0098] R-NH2+C2H4O→R-NH-(CH2CH2O)-H

[0099] Preferably, the mixed gas is firstly used to generate microbubbles of about 50 μm using a microbubble generator, and then the microbubbles are introduced into the mixed solution to accelerate the reaction efficiency of ethylene oxide and polyethylene polyamine.

[0100] It is understood that in this process, the liquid phase is heated by the gas phase to increase the reaction rate and to keep the liquid phase temperature the same as the gas phase temperature, and the reaction time is about 1.5 h.

[0101] (d) Filtering the post-reaction solution using a molecular sieve as an adsorption filter material to remove a portion of the sodium hydroxide and suspended solids that may have been generated during the reaction, and removing the organic solvent from the post-reaction solution by water bath distillation to obtain a modified polyethylene polyamine. It is understood that residual sodium hydroxide in the modified polyethylene polyamine will not affect the use of the polyethylene polyamine.

[0102] Accordingly, the modified polyethylene polyamine is dissolved in an organic solvent, and the organic solvent is sprayed into the inert gas to obtain a vapor deposition gas source 18 .

[0103] It is understandable that during the actual production process, the prepared filter element 5051 needs to be stored in a dry place isolated from air.

[0104] Furthermore, the present invention also relates to a filter element for deep dehydration and deacidification of natural gas, which is prepared by the above-mentioned preparation method. The filter element 5051 is based on a porous filter element, which can physically adsorb carbon dioxide, hydrogen sulfide, etc., and the surface of the pore channels inside the filter element 5051 is loaded with polyethylene polyamine, so that when natural gas passes through the pores, polyethylene polyamine further reacts chemically with water, carbon dioxide, hydrogen sulfide, etc. to achieve chemical adsorption of the above-mentioned substances, thereby forming a filter element 5051 in which physical adsorption and chemical adsorption are coordinated to achieve a deep adsorption effect on impurities in natural gas.

[0105] In actual use, the polyethylene polyamine in the filter element 5051 can adsorb impurities such as carbon dioxide, hydrogen sulfide, and water in natural gas through chemical reactions, and the porous filter element structure can assist in the adsorption of carbon dioxide and hydrogen sulfide through physical adsorption. It can be known that the chemical reactions between polyethylene polyamine and water, carbon dioxide, hydrogen sulfide, etc. are reversible at high temperatures. Therefore, after the physical adsorption and chemical adsorption are completed, they can be regenerated by heating and decomposition.

[0106] If the polyethylene polyamine loses its effect after repeated recycling, the filter element 5051 can be calcined in air at 500 degrees to gasify and remove the polyethylene polyamine, and the above steps 2 to 5 can be repeated, and the polyethylene polyamine can be reloaded. The porous filter element can be recycled, shortening the processing process and saving material costs.

[0107] Example 1:

[0108] (1) 100 parts of 50 nm magnesium oxide were selected as the adsorption substrate, 3 parts of aluminum silicate, 3 parts of sodium silicate and 15 parts of 0.1 mm glass fiber were added to the magnesium oxide, and water was added to mix evenly, and then dried at 110 ° C to form the formed magnesium oxide substrate; the formed magnesium oxide substrate was calcined at 450 ° C to remove moisture, and a cylindrical porous filter element with a wall thickness of 30 mm was obtained;

[0109] (2) Nitrogen containing 0.5% hydrogen fluoride is passed into the porous filter element until the porosity of the porous filter element reaches about 10 μm;

[0110] (3) Soak the porous filter element in an anhydrous ethanol solution containing 5% piperazine until it is completely soaked;

[0111] (4) An anhydrous ethanol solution containing 0.3% polyethylene polyamine was sprayed into nitrogen at 75°C at a volume ratio of 1:10 to obtain a vapor deposition gas source 18; polyethylene polyamine was loaded into the pores of a magnesium oxide filter element by vapor deposition to obtain a filter element 5051 with a polyethylene polyamine content of 10%.

[0112] Example 2:

[0113] (1) 100 parts of 50 nm magnesium oxide were selected as the adsorption substrate, 4 parts of aluminum silicate, 4 parts of sodium silicate and 12 parts of 0.1 mm glass fiber were added to the magnesium oxide, and water was added to mix evenly, and then dried at 110 ° C to form the formed magnesium oxide substrate; the formed magnesium oxide substrate was calcined at 450 ° C to remove moisture, and a cylindrical porous filter element with a wall thickness of 30 mm was obtained;

[0114] (2) Nitrogen containing 0.8% hydrogen fluoride is passed into the porous filter element until the porosity of the porous filter element reaches about 10 μm;

[0115] (3) Soak the porous filter element in an anhydrous ethanol solution containing 10% piperazine until it is completely soaked;

[0116] (4) Polyethylene polyamine was modified by using ethylene oxide. The process was as follows: polyethylene polyamine was mixed with an ethanol solution containing 0.5% sodium hydroxide at a mass ratio of 1:5 to prepare a mixed solution; ethylene oxide was mixed with nitrogen at a molar ratio of 1:2, and the gas temperature was controlled at 140°C. The gas was generated by a microbubble generator with a size of 50 microns and introduced into the mixed solution and stirred for reaction. After the reaction lasted for 1.5 hours, the solution was filtered with a molecular sieve and distilled in a water bath to obtain the modified polyethylene polyamine.

[0117] Then, an anhydrous ethanol solution containing 0.4% modified polyethylene polyamine was sprayed into 85°C nitrogen at a volume ratio of 1:10 to obtain a vapor deposition gas source 18; the polyethylene polyamine was loaded into the pores of the magnesium oxide filter element by vapor deposition to obtain a filter element 5051 with a polyethylene polyamine content of 15%.

[0118] Example 3:

[0119] (1) 100 parts of 50 nm magnesium oxide were selected as the adsorption substrate, 5 parts of aluminum silicate, 5 parts of sodium silicate and 10 parts of 0.1 mm glass fiber were added to the magnesium oxide, and water was added to mix evenly, and then dried at 110 ° C to form the formed magnesium oxide substrate; the formed magnesium oxide substrate was calcined at 450 ° C to remove moisture, and a cylindrical porous filter element with a wall thickness of 30 mm was obtained;

[0120] (2) Pass nitrogen containing 1% hydrogen fluoride into the porous filter element until the porosity of the porous filter element reaches about 10 μm;

[0121] (3) Soak the porous filter element in an anhydrous ethanol solution containing 15% piperazine until it is completely soaked;

[0122] (4) An anhydrous ethanol solution containing 0.5% polyethylene polyamine was sprayed into nitrogen at 90°C at a volume ratio of 1:10 to obtain a vapor deposition gas source 18; polyethylene polyamine was loaded into the pores of a magnesium oxide filter element by vapor deposition to obtain a filter element 5051 with a polyethylene polyamine content of 20%.

[0123] Example 4:

[0124] (1) 100 parts of 50 nm magnesium oxide were selected as the adsorption substrate, 5 parts of aluminum silicate, 5 parts of sodium silicate and 10 parts of 0.1 mm glass fiber were added to the magnesium oxide, and water was added to mix evenly, and then dried at 110 ° C to form the formed magnesium oxide substrate; the formed magnesium oxide substrate was calcined at 450 ° C to remove moisture, and a cylindrical porous filter element with a wall thickness of 30 mm was obtained;

[0125] (2) Pass nitrogen containing 1% hydrogen fluoride into the porous filter element until the porosity of the porous filter element reaches about 10 μm;

[0126] (3) Soak the porous filter element in an anhydrous ethanol solution containing 15% piperazine until it is completely soaked;

[0127] (4) Polyethylene polyamine was modified by using ethylene oxide. The process was as follows: polyethylene polyamine was mixed with an ethanol solution containing 1% sodium hydroxide at a mass ratio of 1:5 to prepare a mixed solution; ethylene oxide was mixed with nitrogen at a molar ratio of 1:2, and the gas temperature was controlled at 160°C. The gas was generated by a microbubble generator with a size of 50 microns and introduced into the mixed solution and stirred for reaction. After the reaction lasted for 1.5 hours, the solution was filtered with a molecular sieve and distilled in a water bath to obtain the modified polyethylene polyamine.

[0128] Then, an anhydrous ethanol solution containing 0.5% modified polyethylene polyamine was sprayed into 90°C nitrogen at a volume ratio of 1:10, and an anhydrous ethanol solution containing 15% piperazine was sprayed into 90°C nitrogen to obtain a vapor deposition gas source 18; the polyethylene polyamine and the polyethylene polyamine activator were loaded into the pores of the magnesium oxide filter element by vapor deposition to obtain a filter element 5051 with a polyethylene polyamine content of 20%.

[0129] Example 5:

[0130] (1) 100 parts of 50 nm magnesium oxide were selected as the adsorption substrate, 5 parts of aluminum silicate, 5 parts of sodium silicate and 10 parts of 0.1 mm glass fiber were added to the magnesium oxide, and water was added to mix evenly, and then dried at 110 ° C to form the formed magnesium oxide substrate; the formed magnesium oxide substrate was calcined at 450 ° C to remove moisture, and a cylindrical porous filter element with a wall thickness of 30 mm was obtained;

[0131] (2) Pass nitrogen containing 1% hydrogen fluoride into the porous filter element until the porosity of the porous filter element reaches about 10 μm;

[0132] (3) Soak the porous filter element in an anhydrous ethanol solution containing 15% piperazine until it is completely soaked;

[0133] (4) Polyethylene polyamine was modified by using ethylene oxide. The process was as follows: polyethylene polyamine was mixed with an ethanol solution containing 1% sodium hydroxide at a mass ratio of 1:5 to prepare a mixed solution; ethylene oxide was mixed with nitrogen at a molar ratio of 1:2, and the gas temperature was controlled at 135°C. The gas was generated by a microbubble generator with a size of 50 microns and introduced into the mixed solution and stirred for reaction. After the reaction lasted for 1.5 hours, the solution was filtered with a molecular sieve and distilled in a water bath to obtain the modified polyethylene polyamine.

[0134] Then, an anhydrous ethanol solution containing 0.5% modified polyethylene polyamine was sprayed into 90°C nitrogen at a volume ratio of 1:10, and an anhydrous ethanol solution containing 15% piperazine was sprayed into 90°C nitrogen to obtain a vapor deposition gas source 18; the vapor deposition gas source 18 was atomized and homogenized using ultrasound, and the polyethylene polyamine was loaded into the pores of the magnesium oxide filter element by vapor deposition, and ultrasound was continuously emitted to the filter element during the deposition process to obtain a filter element 5051 with a polyethylene polyamine content of 20%.

[0135] Comparative Example:

[0136] 50nm magnesium oxide was selected as the adsorption substrate, mixed with water, and then dried at 110°C to form the substrate; the formed magnesium oxide substrate was calcined at 450°C to remove moisture, thereby obtaining a cylindrical porous filter element with a wall thickness of 30mm.

[0137] Furthermore, the filter elements prepared in Examples 1 to 5 and the comparative example were respectively placed in the filter 505, and the natural gas that had been dehydrated and deacidified was used as the initial sample for deep dehydration and deacidification test; six 1000L initial natural gas samples were respectively passed into the filter chamber 5 for filtration; the moisture content of the 1000L initial natural gas sample measured by the first analysis indicator 8 was 92mg / m 3 , carbon dioxide content is 2.1%V / V, hydrogen sulfide content is 5.3mg / m 3 ; Then the component content in the filtered natural gas is measured by the second analysis indicator 9, and the measured content of each impurity gas is shown in Table 1 below.

[0138] Table 1 Impurity removal results of Examples and Comparative Examples

[0139] <![CDATA[Water content (mg / m 3 )]]> Carbon dioxide (%V / V) <![CDATA[Total sulfur (mg / m 3 )]]> Example 1 26.47 0.51 1.17 Example 2 23.55 0.39 0.92 Example 3 14.71 0.37 0.81 Example 4 14.96 0.34 0.75 Example 5 12.94 0.30 0.63 Comparative Example 70.53 1.57 4.13

[0140] According to the test results in the above table, it can be seen that after deep filtration of natural gas by the filter element 5051 prepared by the preparation method in this application, the impurity removal effect is obvious and the impurity gas content in natural gas can be effectively reduced.

[0141] The filtering device for deep dehydration and deacidification of natural gas of the present invention has a simple structure and is easy to operate. It can effectively filter out impurity gases such as moisture, carbon dioxide, and hydrogen sulfide in natural gas, achieve deep dehydration and deacidification of natural gas, and realize the recycling of the filter. It has good application prospects and promotion value.

[0142] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A filtering device for deep dehydration and deacidification of natural gas, characterized in that: It includes a filter chamber, a first air inlet pipe, a second air inlet pipe, an air outlet pipe and a recovery air pipe; The filter chamber comprises an air inlet end, an air outlet end and a filter, wherein the air inlet end and the air outlet end are separated by the filter; the filter comprises a plurality of filter elements, wherein the filter elements comprise a porous filter element and polyethylene polyamine and a polyethylene polyamine activator supported on the porous filter element; and the filter element is prepared by the following steps: (1) The adsorption material is mixed with water, dried and formed, and then calcined to form a porous filter element; (2) Inert gas containing hydrofluoric acid is passed into the porous filter element by vapor phase etching; (3) Soak the porous filter element in an organic solvent containing polyethylene polyamine activator until it is completely soaked; (4) Spraying an organic solvent containing polyethylene polyamine into an inert gas at a certain temperature as a vapor deposition gas source, and loading the polyethylene polyamine into a porous filter element by vapor deposition, and removing the organic solvent to obtain a filter element capable of deep dehydration and deacidification; The first air inlet pipe is in communication with the air inlet end of the filter chamber; The air outlet pipe is connected to the air outlet end of the filter chamber; The second air inlet pipe is in communication with the filter chamber, and a heating assembly is provided on the second air inlet pipe; The recovery air pipe is in communication with the filter chamber; During filtration, natural gas enters the filter chamber through the first air inlet pipe, the filter in the filter chamber deeply filters the natural gas to remove impurities in the natural gas, and the filtered natural gas is discharged through the air outlet pipe; During analysis, inert gas is introduced into the second air inlet pipe, and the inert gas is heated to the analysis temperature by the heating component and then introduced into the filter chamber to heat and analyze the filter element. The inert gas and the analyzed impurity gas are discharged through the recovery air pipe.

2. The filtering device for deep dehydration and deacidification of natural gas according to claim 1, characterized in that: The polyethylene polyamine is a modified polyethylene polyamine obtained by modifying polyethylene polyamine with ethylene oxide, and the modification method includes: (a) mixing polyethylene polyamine with an organic solvent containing 0.5-1% sodium hydroxide to form a mixed solution; (b) mixing ethylene oxide with an inert gas to obtain a mixed gas; (c) introducing a mixed gas at 140-160° C. into the mixed solution to stir, mix, and react; (d) filtering the solution after the reaction, and removing the organic solvent in the solution by water bath distillation to obtain modified polyethylene polyamine; and / or, In step (4), the vapor deposition gas source is first atomized and homogenized by ultrasound, and the ultrasonic generator is directed toward the porous filter element to transmit the ultrasonic wave to the porous filter element, and the process continues throughout the entire loading process.

3. The filtering device for deep dehydration and deacidification of natural gas according to claim 1, characterized in that: The filter chamber has a plurality of filter areas sequentially arranged from the air inlet end to the air outlet end, and the filter is arranged in each filter area to perform multi-stage filtration on the incoming natural gas.

4. The filtering device for deep dehydration and deacidification of natural gas according to claim 3, characterized in that: The filter chamber is provided with a primary filter area and a secondary filter area in sequence along the direction from the air inlet end to the air outlet end.

5. The filtering device for deep dehydration and deacidification of natural gas according to claim 1, characterized in that: A spray assembly is further provided in the filter chamber, the spray assembly is communicated with the second air inlet pipe, and at least one spray head is provided corresponding to each filter element.

6. The filtering device for deep dehydration and deacidification of natural gas according to claim 1, characterized in that: An air distribution duct is provided in the filter chamber, the air distribution duct is communicated with the first air inlet pipe, and at least one air outlet is provided on the air distribution duct corresponding to each filter element.

7. The filtering device for deep dehydration and deacidification of natural gas according to claim 1, characterized in that: The first air inlet pipe is provided with a pressure indicator, a temperature indicator and a first analysis indicator to detect the pressure, temperature and component content of the incoming natural gas; and / or, A pressure differential detection meter is provided corresponding to the filter chamber to detect the pressure differential in the filter chamber; and / or, The gas outlet pipe is provided with a second analysis indicator to detect the content of components in the filtered natural gas; and / or, The second air inlet pipe and the air recovery pipe are respectively provided with valves to control the entry of gas.

8. The filtering device for deep dehydration and deacidification of natural gas according to claim 1, characterized in that: The end of the recovery air pipe away from the filter chamber is connected to the regeneration waste gas treatment device, and the regeneration waste gas treatment device regenerates the inert gas introduced into the filter chamber and the impurity gas analyzed, wherein the regenerated inert gas can be circulated into the second air inlet pipe as a gas source.

9. The filtering device for deep dehydration and deacidification of natural gas according to any one of claims 1 to 8, characterized in that: The filter element is a cylindrical structure with one end open. The open end of the filter element is communicated with the air inlet end of the filter chamber, and mesh frames are fixedly arranged on the inner and outer sides of the filter element.

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