An integrated production unit for dimethyl ether and sodium methoxide

Abstract

This application discloses an integrated production apparatus for dimethyl ether and sodium methoxide, comprising a refined methanol distillation column, a sodium methoxide synthesis column, a water-methanol distillation column, a methanol dehydration reactor, and a dimethyl ether distillation column. A first pipeline connects the top of the refined methanol distillation column to the lower part of the sodium methoxide synthesis column, and a second pipeline connects the top of the sodium methoxide synthesis column to the middle section of the refined methanol distillation column. The second pipeline is connected to a boric acid tank and includes a front section and a rear section. One end of the front section is connected to the lower part of the boric acid tank, and the other end is connected to the top of the sodium methoxide synthesis column. One end of the rear section is connected to the upper part of the boric acid tank, and the other end is connected to the middle section of the methanol distillation column. A boric acid filter layer is provided in the middle section of the boric acid tank. This application utilizes the boric acid tank to remove sodium hydroxide mixed into the methanol after sodium methoxide preparation, which helps to reduce the impact of sodium hydroxide on equipment and dimethyl ether catalyst.

Description

Technical Field

[0001] This application relates to the field of chemical production equipment, and in particular to an integrated production unit for dimethyl ether and sodium methoxide. Background Technology

[0002] Methanol, also known as hydroxymethane, is an organic compound and the simplest saturated monohydric alcohol, with the chemical formula CH3OH / CH4O and a boiling point of 64.7℃. Methanol is a basic organic raw material and can be used to manufacture chemical products such as dichloromethane, methylamine, dimethyl sulfate, dimethyl ether, and sodium methoxide.

[0003] In industrial applications, when methanol is used to prepare other compound products, only a portion of the methanol input at any given time participates in the reaction to form the desired product. A large portion of the methanol remains unreacted. This unreacted methanol can be reused after processes such as distillation or filtration. Under these conditions, methanol, as a basic raw material capable of producing multiple products, can be used in actual industrial production to simultaneously manufacture different chemical products.

[0004] When using methanol to simultaneously produce different chemical products, the methanol feedstock is used to produce one chemical product, and the remaining methanol is then used as a feedstock for other chemical products. This allows for more compact and efficient production equipment. However, after methanol has participated in the reaction, the remaining methanol inevitably carries some of the feedstock from other materials besides methanol. For example, the production of sodium methoxide requires sodium hydroxide in addition to methanol. When the methanol used to produce sodium methoxide is then used for other chemical products, the sodium hydroxide carried in the remaining methanol will adversely affect the equipment and catalysts, thus negatively impacting the co-production of different products using methanol as a feedstock. Summary of the Invention

[0005] To address the adverse effects of sodium hydroxide carried in the residual methanol during sodium methoxide production on equipment and catalytic reactants when using methanol as a raw material to simultaneously produce sodium methoxide and other products, this application provides an integrated dimethyl ether and sodium methoxide production apparatus.

[0006] The integrated production unit for dimethyl ether and sodium methoxide provided in this application adopts the following technical solution:

[0007] An integrated dimethyl ether and sodium methoxide production unit includes a refined methanol distillation column, a sodium methoxide synthesis column, a water-methanol distillation column, a methanol dehydration reactor, and a dimethyl ether distillation column. A first pipeline connects the top of the refined methanol distillation column to the lower part of the sodium methoxide synthesis column, and a second pipeline connects the top of the sodium methoxide synthesis column to the middle part of the refined methanol distillation column. The second pipeline is connected to a boric acid tank and includes a front section and a rear section. One end of the front section of the second pipeline is connected to the lower part of the boric acid tank, and the other end is connected to the sodium methoxide tank. At the top of the synthesis tower, one end of the second pipeline is connected to the upper part of the boric acid tank, and the other end of the second pipeline is connected to the waist of the methanol distillation tower; the waist of the boric acid tank is provided with a boric acid filter layer; a third pipeline connects the bottom of the refined methanol distillation tower to the top of the water methanol distillation tower, and a fourth pipeline connects the water methanol distillation tower to the top of the methanol dehydration reactor; a fifth pipeline connects the bottom of the methanol dehydration reactor to the waist of the dimethyl ether distillation tower, and a sixth pipeline connects the bottom of the dimethyl ether distillation tower to the waist of the water methanol distillation tower.

[0008] By adopting the above technical solution, when the integrated dimethyl ether and sodium methoxide production unit is operating, raw methanol is added to the upper part of the refined methanol distillation column. The raw methanol is vaporized into first methanol gas in the distillation column. The first methanol gas enters the lower part of the sodium methoxide synthesis column. At the same time, sodium hydroxide methanol solution is added from the upper part of the sodium methoxide synthesis column. The sodium hydroxide methanol solution reacts with the first methanol gas to generate sodium methoxide methanol solution. The first methanol gas that has not participated in the reaction in the sodium methoxide synthesis column is drawn off from the top of the sodium methoxide synthesis column as second methanol gas. The second methanol gas carries some water generated after the reaction of sodium methoxide. The second methanol gas is sent back to the methanol distillation column through a second pipeline to participate in the distillation. Aqueous methanol liquid is drawn from the bottom of the methanol distillation column and transported to the upper part of the water-methanol distillation column via the third pipeline. The methanol liquid is vaporized into aqueous third methanol gas in the water-methanol distillation column. The third methanol gas is transported to the methanol dehydration reactor via the fourth pipeline. The third methanol gas undergoes a dehydration reaction in the methanol dehydration reactor to produce dimethyl ether and water. The dimethyl ether, water, and remaining methanol drawn from the bottom of the methanol dehydration reactor are transported to the dimethyl ether distillation column via the fifth pipeline for distillation to obtain dimethyl ether and aqueous methanol. The dimethyl ether is collected from the top of the dimethyl ether distillation column, and the aqueous methanol is transported from the bottom of the dimethyl ether distillation column back to the water-methanol distillation column via the sixth pipeline to participate in the distillation.

[0009] Sodium methoxide and water are produced during the preparation of sodium methoxide, resulting in sodium hydroxide in the second methanol gas. When water exists in the form of mist droplets, it can carry strong sodium oxide. By passing the second methanol gas through a boric acid tank and filtering out sodium hydroxide using a boric acid filter layer, it is beneficial to reduce the corrosive effect of sodium hydroxide combined with water on the equipment and the impact on the quality of the catalyst for the methanol dehydration reaction.

[0010] Optionally, the boric acid tank includes a tank body and a top cover, the top cover being detachably connected to the tank body. The inner wall of the boric acid tank is provided with a filter plate for supporting the boric acid filtration layer. The boric acid in the filtration layer is boric acid particles. A sampling tube is provided inside the tank body, the sampling tube being vertically positioned and passing through and connected to both the filter plate and the bottom wall of the boric acid tank. A sleeve is fixedly provided on the lower surface of the top cover, the inner circumferential wall of the sleeve being sealed to the outer circumferential wall of the upper end of the sampling tube. A sampling hole is provided on the peripheral wall of the upper end of the sampling tube, and a lower end cap is detachably connected to the lower end of the sampling tube, which is located on the outside of the tank body. When the sampling tube abuts against the upper cover, the sampling tube is at the upper limit position, and the sampling hole is located inside the sleeve. The sampling tube is provided with a lower limit structure, which is used to limit the lowest position of the sampling tube when it moves vertically. When the sampling tube is at the lower limit position, the edge line of the sampling hole intersects with the upper surface of the filter plate.

[0011] By adopting the above technical solution, the sampling tube is simultaneously connected to the filter plate and the lower end cover of the boric acid tank. The sampling tube can move up and down relative to the boric acid tank and the filter plate. When it is necessary to sample the boric acid in the boric acid filter layer, the sampling tube is moved to the lower limit position, and the inner edge line of the small end of the filter plate is located between the lowest and highest points of the sampling hole, so that the boric acid particles in the boric acid filter layer can enter the sampling tube through the sampling hole and fall on the lower end cover. After sampling is completed, the sampling tube is moved upward so that the upper end of the sampling tube is inserted into the sleeve, and the sleeve is used to seal the sampling hole, thereby separating the inner cavity of the sampling tube from the inner cavity of the boric acid tank. Then the lower end cover is removed, the boric acid sample in the sampling tube is taken out, and the boric acid reaction consumption is tested to determine whether the boric acid needs to be replaced.

[0012] Optionally, the filter plate is provided with a through hole for the sampling tube to pass through, and the filter plate is provided with a conical slope surrounding the through hole, the conical slope gradually sloping downwards in the direction close to the through hole.

[0013] By adopting the above technical solution, when the sampling tube is at the lower limit, the boric acid particles on the filter plate can slide into the sampling hole along the conical slope, making it easier for the boric acid particles to enter the sampling hole.

[0014] Optionally, the lower end of the sampling tube is provided with an external thread, the bottom wall of the boric acid tank is provided with an internal thread sleeve, the sampling tube is threadedly connected to the internal thread sleeve through the external thread, the lower end cover is provided with an internal thread, and the lower end cover is threadedly connected to the sampling tube.

[0015] By adopting the above technical solution, the sampling tube is connected to the internal threaded sleeve located at the bottom of the boric acid tube. By rotating the sampling tube and the internal threaded sleeve in a spiral motion, the sampling tube can be moved up and down. Moving the sampling tube up and down by spiral rotation is more labor-saving and allows for more precise adjustment of the sampling tube's position.

[0016] Optionally, a dimensional allowance is left between the lower end of the internal thread and the end wall of the lower end cover. An observation hole is provided on the peripheral wall of the lower end cover. The observation hole is located between the internal thread and the bottom wall of the lower end cover. A transparent element is embedded in the observation hole of the lower end cover.

[0017] By adopting the above technical solution, a transparent part is embedded in the lower end cover. The installation position of the transparent part is between the internal thread and the bottom wall of the lower end cover, so that the boric acid particles falling on the transparent cover can be seen through the lower end cover. This allows the staff to confirm whether the sampling tube has obtained a sample, thereby reducing the situation where the sampling tube is moved up and reset, but the sampling tube has not obtained a sample.

[0018] Optionally, the upper surface of the filter plate is provided with filter cotton, and the upper surface of the filter cotton is covered with a filter screen.

[0019] By adopting the above technical solution, the filter cotton has a fluffy and dense pore, which can better retain boric acid particles and reduce the leakage of boric acid particles to the bottom wall of the boric acid tank. The filter cotton is covered with a filter screen to keep it flat.

[0020] Optionally, the second pipeline is connected to a bypass pipeline, one end of which is connected to the front section of the second pipeline, and the other end of which is connected to the rear section of the second pipeline. The bypass pipeline is equipped with a Y-type filter, which includes a housing and a cylindrical filter element. The housing has an installation port for installing the cylindrical filter element and an end cap for closing the installation port. The cylindrical filter element is filled with boric acid packing. The second pipeline is equipped with two main switching valves, which are located on both sides of the boric acid tank. The bypass pipeline is equipped with two auxiliary switching valves, which are located on both sides of the Y-type filter.

[0021] By adopting the above technical solution, the main switch valve controls the on / off state of the second pipeline, and the auxiliary switch valve controls the on / off state of the bypass pipeline. During normal operation of the integrated dimethyl ether and sodium methoxide production unit, the main switch valve is open and the auxiliary switch valve is closed. The second methanol gas from the top of the sodium methoxide synthesis tower is mainly transported to the refined methanol distillation tower through the second pipeline. During this process, the methanol gas passes through a boric acid tank, where the boric acid removes sodium hydroxide from the methanol gas. When it is necessary to replace the boric acid in the tank or to perform maintenance on the boric acid tank, the main switch valve is closed and the auxiliary switch valve is opened, allowing the second methanol gas from the top of the sodium methoxide synthesis tower to be transported to the methanol distillation tower through the bypass pipeline. The boric acid packing in the Y-type filter of the bypass pipeline removes sodium hydroxide from the methanol gas. The bypass pipeline serves as a temporary passage for the second methanol gas from the top of the sodium methoxide synthesis tower to the refined methanol distillation tower. The boric acid packing in the Y-type filter is used to temporarily treat the sodium hydroxide carried by the methanol gas passing through the bypass pipeline. This method not only meets the requirements for sodium hydroxide treatment but also has the advantages of requiring less boric acid packing, minimizing waste, and facilitating replacement.

[0022] Optionally, the cylindrical filter element has an inner filter cylinder on its inner side, and a filling area for filling boric acid packing is formed between the cylindrical filter element and the inner filter cylinder.

[0023] By adopting the above technical solution, boric acid packing material is filled in the filling area between the cylindrical filter element and the inner filter element. When methanol gas passes through the Y-type filter, the methanol gas first enters the inner side of the inner filter element, and then passes through the boric acid packing material located in the filling area, thereby removing sodium hydroxide from the methanol gas. Since the boric acid is only filled in the annular space between the cylindrical filter element and the inner filter element, it helps to reduce the space occupied by the boric acid packing material in the cylindrical filter element, thus helping to minimize the resistance of methanol gas passing through the boric acid packing material while meeting the requirements for filtering methanol gas.

[0024] Optionally, the inner filter cartridge has an outwardly flared flange at one end near the end cap, and the outer peripheral surface of the flange abuts against the inner peripheral wall of the cylindrical filter element.

[0025] By adopting the above technical solution, the flange of the inner filter cartridge abuts against the inner wall of the cylindrical filter element, which helps to keep the spatial shape of the filling area between the cylindrical filter element and the inner filter cartridge stable and regular, and helps to make the boric acid packing more evenly distributed.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. Sodium methoxide and water are produced during the preparation of sodium methoxide, resulting in sodium hydroxide in the second methanol gas. When water exists in the form of mist droplets, it can carry strong sodium oxide. By passing the second methanol gas through a boric acid tank and filtering out sodium hydroxide using the boric acid filter layer, it is beneficial to reduce the corrosive effect of sodium hydroxide combined with water on the equipment and the impact on the quality of the catalyst for the methanol dehydration reaction.

[0028] 2. The bypass pipeline serves as a temporary passage for the second methanol gas from the top of the sodium methoxide synthesis tower to be transported to the refined methanol distillation tower. The boric acid packing in the Y-type filter is used to temporarily treat the sodium hydroxide carried by the methanol gas passing through the bypass pipeline. It can meet the requirements for treating sodium hydroxide while also having the advantages of requiring less boric acid packing, minimizing waste, and being easy to replace. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of this embodiment.

[0030] Figure 2 This is a schematic diagram of the boric acid tank to show the structure when the sampling tube is at its upper limit.

[0031] Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle.

[0032] Figure 4 yes Figure 2 A magnified view of a portion of point B in the middle.

[0033] Figure 5 This is a schematic diagram of the boric acid tank to show the sample tube being in the lower limit position.

[0034] Figure 6 This is a schematic diagram of the Y-type filter in this embodiment.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Refined methanol distillation column; 2. Sodium methoxide synthesis column; 3. Water-methanol distillation column; 4. Methanol dehydration reactor; 5. Dimethyl ether distillation column; 6. Boric acid tank; 61. Tank body; 62. Top cover; 621. Sleeve; 622. Sealing ring; 63. Boric acid filter layer; 64. Filter plate; 641. Through hole; 642. Conical slope; 65. Filter cotton; 66. Filter screen; 67. Sampling tube; 671. Sampling hole; 672. External thread; 673. Guide tube; 68. Internal thread sleeve; 681. Annular sealing ring; 69. Lower end cover; 69 1. Observation hole; 692. Transparent part; 7. First pipeline; 8. Second pipeline; 81. Front section of the second pipeline; 82. Rear section of the second pipeline; 83. Main switch valve; 9. Third pipeline; 10. Fourth pipeline; 20. Fifth pipeline; 30. Sixth pipeline; 40. Bypass pipeline; 401. Auxiliary switch valve; 50. Y-type filter; 501. Housing; 502. Cylindrical filter element; 5011. Mounting port; 503. End cap; 504. Inner filter cylinder; 505. Flange; 506. Filling area; 507. Boric acid packing. Detailed Implementation

[0037] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0038] This application discloses an integrated production apparatus for dimethyl ether and sodium methoxide. (Refer to...) Figure 1 The integrated dimethyl ether and sodium methoxide production unit includes a refined methanol distillation column 1, a sodium methoxide synthesis column 2, a water-methanol distillation column 3, a methanol dehydration reactor 4, and a dimethyl ether distillation column 5. A first pipeline 7 connects the top of the refined methanol distillation column 1 to the lower part of the sodium methoxide synthesis column 2; a second pipeline 8 connects the top of the sodium methoxide synthesis column 2 to the middle section of the refined methanol distillation column 1; a third pipeline 9 connects the bottom of the refined methanol distillation column 1 to the top of the water-methanol distillation column 3; a fourth pipeline 10 connects the top of the water-methanol distillation column 3 to the top of the methanol dehydration reactor 4; a fifth pipeline 20 connects the bottom of the methanol dehydration reactor 4 to the middle section of the dimethyl ether distillation column 5; and a sixth pipeline 30 connects the bottom of the dimethyl ether distillation column 5 to the middle section of the water-methanol distillation column 3. It should be noted that in this embodiment, the "middle section" of each component refers to the middle position along the height direction of the corresponding component.

[0039] When the integrated dimethyl ether and sodium methoxide production unit is operating, raw methanol is added to the upper part of the refined methanol distillation column 1. The raw methanol is vaporized in the distillation column into first methanol gas, which enters the lower part of the sodium methoxide synthesis column 2. Simultaneously, sodium hydroxide methanol solution is added from the upper part of the sodium methoxide synthesis column 2. The sodium hydroxide methanol solution reacts with the first methanol gas to generate sodium methoxide methanol solution. The first methanol gas that did not participate in the reaction in the sodium methoxide synthesis column 2 is drawn off from the top of the sodium methoxide synthesis column 2 as second methanol gas. The second methanol gas carries some water generated after the sodium methoxide reaction and is sent back to the methanol distillation column through the second pipeline 8 to participate in distillation. The bottom of the refined methanol distillation column 1... Aqueous methanol liquid is drawn out and transported to the upper part of water-methanol distillation column 3 via the third pipeline 9. The methanol liquid is vaporized in water-methanol distillation column 3 into aqueous third methanol gas. The third methanol gas is transported to methanol dehydration reactor 4 via the fourth pipeline. The third methanol gas undergoes a dehydration reaction in methanol dehydration reactor 4 to produce dimethyl ether and water. The dimethyl ether, water and remaining methanol drawn out from the bottom of methanol dehydration reactor 4 are transported to dimethyl ether distillation column 5 via the fifth pipeline 20 for distillation to obtain dimethyl ether and aqueous methanol. Dimethyl ether is collected from the top of dimethyl ether distillation column 5, and aqueous methanol is transported from the bottom of dimethyl ether distillation column 5 back to water-methanol distillation column 3 via the sixth pipeline 30 to participate in distillation.

[0040] Reference Figure 1 and Figure 2 The second pipeline 8 is connected to a boric acid tank 6, which includes a tank body 61 and a top cover 62. The top cover 62 is bolted to the tank body 61, and a sealing ring 622 is provided between the tank body 61 and the top cover 62. The second pipeline 8 includes a front section 81 and a rear section 82. One end of the front section 81 is connected to the lower part of the tank body 61, and the other end is connected to the top of the sodium methoxide synthesis tower 2. One end of the rear section 82 is connected to the upper part of the tank body 61, and the other end is connected to the waist of the refined methanol distillation tower 1. The waist of the boric acid tank 6 is provided with a boric acid filter layer 63, and the boric acid in the boric acid filter layer 63 is boric acid particles.

[0041] Sodium methoxide and water are produced during the preparation of sodium methoxide. When the water exists in the form of mist droplets, it can carry strong sodium oxide, so that the second methanol gas in the sodium methoxide synthesis tower 2 contains sodium hydroxide. When the second methanol gas passes through the boric acid filter layer 63 in the boric acid tank 6, the boric acid filter layer 63 can filter out the sodium hydroxide, reducing the corrosion of equipment by sodium hydroxide and the impact on the catalyst of the methanol dehydration reaction.

[0042] Reference Figure 2 The inner wall of the boric acid tank 6 is provided with a filter plate 64 for supporting the boric acid filter layer 63. The filter plate 64 has uniformly distributed filter holes, and the upper surface of the filter plate 64 is covered with filter cotton 65. The upper surface of the filter cotton 65 is covered with a filter screen 66. The boric acid filter layer 63 is laid on the filter screen 66.

[0043] Reference Figure 2 and Figure 3 A sampling tube 67 is provided inside the body 61 of the boric acid tank 6. The sampling tube 67 is vertically arranged and passes through and connects to the filter screen 66, filter cotton 65, filter plate 64, and the bottom wall of the tank body 61 from top to bottom. The filter plate 64 has a through hole 641 for the sampling tube 67 to pass through, and the filter plate 64 has a conical slope 642 surrounding the through hole 641. The conical slope 642 gradually slopes downwards in the direction close to the through hole 641. A guide tube 673 is fixedly provided on the lower surface of the filter plate 64. The guide tube 673 is sleeved and connected to the sampling tube 67, and there is a clearance fit between the guide tube 67 and the sampling tube 67. A sleeve 621 is fixedly installed on the lower surface of the upper cover 62 of the boric acid tank 6. The inner peripheral wall of the sleeve 621 is provided with a sealing layer. The inner peripheral wall of the sleeve 621 is sealed to the outer peripheral wall of the upper end of the sampling tube 67. A sampling hole 671 is opened on the peripheral wall of the upper end of the sampling tube 67.

[0044] Reference Figure 4 The bottom wall of the boric acid tank 6 is fixedly provided with an internal threaded sleeve 68, which is located on the outside of the boric acid tank 6. The lower end of the sampling tube 67 is provided with an external thread 672. The sampling tube 67 is threadedly connected to the internal threaded sleeve 68 through the external thread 672. The part of the peripheral wall of the sampling tube 67 without the external thread 672 serves as the lower limit structure when the sampling tube 67 and the internal threaded sleeve 68 move downwards in a spiral motion. The lower limit structure can also be a component fixed to the outer wall of the sampling tube 67. The lower end of the sampling tube 67 is provided with a lower end cap 69, which is provided with an internal thread. The lower end cap 69 is threadedly connected to the sampling tube 67.

[0045] Reference Figure 2 and Figure 5 When the sampling tube 67 moves upward spirally to the position of abutting the upper cover 62, the sampling tube 67 is at the upper limit position, and the sampling hole 671 is located inside the sleeve 621. The sleeve 621 blocks the sampling hole 671, separating the inner cavity of the sampling tube 67 from the inner cavity of the boric acid tank 6. When the sampling tube 67 moves downward spirally to the lower limit position, the edge line of the sampling hole 671 intersects with the upper surface of the filter plate 64, so that the lowest point of the sampling hole 671 is lower than the upper surface of the filter plate 64, allowing the boric acid particles on the filter plate 64 to enter the inner side of the sampling tube 67 through the sampling hole 671.

[0046] When it is necessary to sample the boric acid particles in the boric acid container 6, the sampling tube 67 is moved to the lower limit position, allowing the boric acid particles to fall through the sampling hole 671 into the lower end cover 69. Then, the sampling tube 67 is moved to the upper limit position, and the lower end cover 69 is removed to discharge the boric acid sample. By testing the boric acid consumption in the boric acid sample, it can be determined whether the boric acid needs to be replaced.

[0047] Reference Figure 4A dimensional allowance is left between the lower end of the internal thread and the end wall of the lower end cover 69. An observation hole 691 is provided on the peripheral wall of the lower end cover 69. The observation hole 691 is located between the internal thread and the bottom wall of the lower end cover 69. A transparent element 692 is embedded in the observation hole 691 of the lower end cover 69. The sampling status of the sampling tube 67 can be observed through the transparent element 692 to reduce the situation where the sampling tube 67 moves up and resets, but the sampling tube 67 has not obtained a sample.

[0048] Reference Figure 4 The lower end face of the internal threaded sleeve 68 is provided with an annular sealing ring 681. When the sampling tube 67 is at the upper limit position, the lower end cover 69 presses against the annular sealing ring 681, so that a good sealing effect is formed between the internal threaded sleeve 68 and the lower end cover 69.

[0049] Reference Figure 1 The second pipeline 8 is connected to a bypass pipeline 40. One end of the bypass pipeline 40 is connected to the front section 81 of the second pipeline, and the other end of the bypass pipeline 40 is connected to the rear section 82 of the second pipeline. The bypass pipeline 40 is equipped with a Y-type filter 50, which includes a housing 501 and a cylindrical filter element 502. The housing 501 has an installation port 5011 for installing the cylindrical filter element 502. The housing 501 is detachably connected to an end cap 503 for sealing the installation port 5011 by bolts. The cylindrical filter element 502 contains... The second pipeline 8 is filled with boric acid packing 507; the second pipeline 8 is equipped with two main switching valves 83, one of which is located at the front section 81 of the second pipeline and the other is installed at the rear section 82 of the second pipeline. That is, the two main switching valves 83 are located on both sides of the boric acid tank 6, and the installation positions of the two main opening valves are located between the two corresponding connection points of the two ends of the bypass pipeline 40 of the second pipeline 8; the bypass pipeline is equipped with two auxiliary switching valves 401, which are located on both sides of the Y-type filter.

[0050] During normal operation of the integrated dimethyl ether and sodium methoxide production unit, the main switch valve 83 is open and the auxiliary switch valve 401 is closed. The second methanol gas at the top of the sodium methoxide synthesis tower 2 passes through the boric acid tank 6, where the boric acid in the tank removes sodium hydroxide from the methanol gas. When it is necessary to replace the boric acid in the boric acid tank 6 or to perform maintenance on the tank 6, the main switch valve 83 is closed and the auxiliary switch valve 401 is opened, allowing the second methanol gas at the top of the sodium methoxide synthesis tower 2 to be transported to the methanol distillation tower through the bypass pipeline 40. The boric acid packing 507 in the Y-type filter 50 of the bypass pipeline 40 can remove sodium hydroxide from the methanol gas.

[0051] Reference Figure 6The cylindrical filter element 502 has an inner filter cylinder 504 inside. The inner filter cylinder 504 has an outwardly turned flange 505 at one end near the end cap 503. The outer circumferential surface of the flange 505 abuts against the inner circumferential wall of the cylindrical filter element 502. A filling area 506 for filling boric acid packing 507 is formed between the cylindrical filter element 502 and the inner filter cylinder 504. Both the cylindrical filter element 502 and the inner filter cylinder 504 are made of wire mesh or thin steel plate with filter holes. The outer circumferential surfaces of both the cylindrical filter element 502 and the inner filter cylinder 504 are covered with filter cloth. The boric acid packing material fills the area between the cylindrical filter element 502 and the inner filter cylinder 504, which helps reduce the space occupied by the boric acid packing material, thereby facilitating the smooth passage of the second methanol gas through the Y-type filter 50.

[0052] The implementation principle of this embodiment is as follows: The integrated dimethyl ether and sodium methoxide production unit uses methanol to produce sodium methoxide and dimethyl ether. The raw materials for producing sodium methoxide include methanol gas and sodium hydroxide methanol solution. The methanol gas remaining after the production of sodium methoxide contains sodium hydroxide. The sodium hydroxide is filtered out by the boric acid filter layer 63 in the boric acid tank 6 or the boric acid packing 507 in the Y-type filter 50, which helps to reduce the corrosion of equipment by sodium hydroxide and the impact on the catalyst of the methanol dehydration reaction.

[0053] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A device for integrated production of dimethyl ether and sodium methoxide, characterized in that it comprises: The application relates to a methanol purification system, which comprises a refined methanol rectifying tower (1), a sodium methoxide synthesis tower (2), a water-methanol rectifying tower (3), a methanol dehydration reactor (4) and a dimethyl ether rectifying tower (5); a first pipeline (7) is connected between the top of the refined methanol rectifying tower (1) and the lower part of the sodium methoxide synthesis tower (2); a second pipeline (8) is connected between the top of the sodium methoxide synthesis tower (2) and the waist part of the refined methanol rectifying tower (1); the second pipeline (8) is connected with a boric acid tank (6); the second pipeline (8) comprises a second pipeline front section (81) and a second pipeline rear section (82); one end of the second pipeline front section (81) is connected with the lower part of the boric acid tank (6); the other end of the second pipeline front section (81) is connected with the top of the sodium methoxide synthesis tower (2); one end of the second pipeline rear section (82) is connected with the upper part of the boric acid tank (6); the other end of the second pipeline rear section (82) is connected with the waist part of the methanol rectifying tower; a boric acid filter layer (63) is arranged at the waist part of the boric acid tank (6); a third pipeline (9) is connected between the bottom of the refined methanol rectifying tower (1) and the top of the water-methanol rectifying tower (3); a fourth pipeline (10) is connected between the water-methanol rectifying tower (3) and the top of the methanol dehydration reactor (4); a fifth pipeline (20) is connected between the bottom of the methanol dehydration reactor (4) and the waist part of the dimethyl ether rectifying tower (5); a sixth pipeline (30) is connected between the bottom of the dimethyl ether rectifying tower (5) and the waist part of the water-methanol rectifying tower (3). The boric acid tank (6) comprises a tank body (61) and an upper cover (62); the upper cover (62) is detachably connected with the tank body (61); the inner wall of the boric acid tank (6) is provided with a filter plate (64) for bearing the boric acid filter layer (63); the boric acid of the boric acid filter layer (63) is boric acid particles; the inner side of the tank body (61) is provided with a sampling pipe (67); the sampling pipe (67) is vertically arranged; the sampling pipe (67) is respectively connected with the filter plate (64) and the bottom wall of the boric acid tank (6); the lower surface of the upper cover (62) is fixedly provided with a sleeve (621); the inner circumferential wall of the sleeve (621) is sealingly connected with the outer circumferential wall of the upper end of the sampling pipe (67); the circumferential wall of the upper end of the sampling pipe (67) is provided with a sampling hole (671); the lower end of the sampling pipe (67) is detachably connected with a lower end cover (69); the lower end cover (69) is located outside the tank body (61); when the sampling pipe (67) abuts against the upper cover (62), the sampling pipe (67) is located at an upper limit position, meanwhile, the sampling hole (671) is located inside the sleeve (621); the sampling pipe (67) is provided with a lower limit position structure; the lower limit position structure is used for limiting the lowest position of the sampling pipe (67) when the sampling pipe (67) moves vertically; when the sampling pipe (67) is located at a lower limit position, the edge line of the sampling hole (671) intersects with the upper surface of the filter plate (64). The filter plate (64) is provided with a through hole (641) for the sampling tube (67) to pass through, and the filter plate (64) is provided with a conical slope surface (642) surrounding the through hole (641), which gradually inclines downward along the direction close to the through hole (641); The lower end of the sampling tube (67) is provided with an external thread (672), the bottom wall of the boric acid tank (6) is provided with an internal thread sleeve (68), the sampling tube (67) is threadedly connected with the internal thread sleeve (68) through the external thread (672), and the lower end cover (69) is provided with an internal thread and is threadedly connected with the sampling tube (67).

2. The device for integrated production of dimethyl ether and sodium methoxide according to claim 1, characterized in that: The lower end of the internal thread and the end wall of the lower end cover (69) are left with a size allowance, the peripheral wall of the lower end cover (69) is provided with an observation hole (691), the observation hole (691) is located between the internal thread and the bottom wall of the lower end cover (69), and a transparent piece (692) is embedded in the observation hole (691) of the lower end cover (69).

3. The device for integrated production of dimethyl ether and sodium methoxide according to claim 1, characterized in that: The upper surface of the filter plate (64) is provided with filter cotton (65), and the upper surface of the filter cotton (65) is covered with a filter screen (66).

4. The device for integrated production of dimethyl ether and sodium methoxide according to claim 1, characterized in that: The second pipeline (8) is connected with a bypass pipeline (40), one end of the bypass pipeline (40) is connected with the front section (81) of the second pipeline, and the other end of the bypass pipeline (40) is connected with the rear section (82) of the second pipeline; the bypass pipeline (40) is provided with a Y-shaped filter (50), the Y-shaped filter (50) comprises a shell (501) and a cylindrical filter element (502), the shell (501) is provided with a mounting port (5011) for mounting the cylindrical filter element (502), the shell (501) is provided with an end cover (503) for closing the mounting port (5011), and the cylindrical filter element (502) is filled with boric acid filler (507); the second pipeline (8) is provided with two main switch valves (83), and the two main switch valves (83) are located on the two sides of the boric acid tank (6), respectively; the bypass pipeline is provided with two auxiliary switch valves (401), and the two auxiliary switch valves (401) are located on the two sides of the Y-shaped filter, respectively.

5. The device for integrated production of dimethyl ether and sodium methoxide according to claim 4, characterized in that: The inner side of the cylindrical filter element (502) is provided with an inner filter cylinder (504), and a filling area (506) for filling boric acid filler (507) is formed between the cylindrical filter element (502) and the inner filter cylinder (504).

6. The device for integrated production of dimethyl ether and sodium methoxide according to claim 5, characterized in that: The end of the inner filter cylinder (504) close to the end cover (503) is provided with an outwardly turned flange (505), and the outer peripheral surface of the flange (505) abuts against the inner peripheral wall of the cylindrical filter element (502).

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