Combined drying tower for removing methane chloride moisture

Abstract

The invention discloses a combined drying tower for removing methane chloride moisture, the top of a drying tower I (1) is provided with a gas outlet (4), a liquid outlet I (6) is communicated with a liquid inlet pipeline (7) through a circulating reflux device I, a bubble cap tower plate (13), an upper drying chamber (14) and a lower drying chamber (15) are arranged in a drying tower II (2), the side surface of the drying tower II (2) is provided with a sulfuric acid inlet (16), and the lower drying chamber (15) is provided with a sulfuric acid outlet (16). A liquid outlet II (19) in the side face of a lower liquid collecting area (17) of the upper drying chamber (14) is connected with a liquid return opening II (20) in the side face of the upper drying chamber (14) through a circulation backflow device II, a circulation backflow device III is arranged between a liquid outlet III (23) and a liquid return opening III (24) of the lower drying chamber (15), and the interior of the lower drying chamber (15) is communicated with the interior of the upper drying chamber (14) through a channel (28). According to the method, the water removal efficiency can be greatly improved, and methane chloride with low water content is obtained.

Description

Technical Field

[0001] The present invention relates to a combined drying tower for removing moisture from methyl chloride. Background Art

[0002] The methanol hydrochlorination unit is an important component in the methyl chloride production unit, and methyl chloride is an important raw material for the production of methyl chloride. At present, in the production process of methyl chloride, the removal of moisture is generally carried out by using a packed tower, and liquid-phase sulfuric acid is used to remove the moisture of methyl chloride. The original sulfuric acid drying tower includes two towers. The first tower is a packed tower, and the second tower is a packed and bubble-cap tower. Wet methyl chloride enters the first sulfuric acid drying tower, and the methyl chloride coming out from the top of the first tower enters the second tower. The upper part of the second tower has 6 layers of bubble caps, and the lower part is packed. After coming out from the bottom of the first tower kettle, it enters the second tower kettle for water absorption treatment. Due to different absorption effects, the greater the concentration of concentrated sulfuric acid, the better the water absorption effect. Since the second tower kettle can only carry out water absorption treatment once, when the concentration of concentrated sulfuric acid in the second tower kettle decreases, the water absorption effect becomes poor. Therefore, the moisture content of methyl chloride after removing moisture by the above method is about 50 PPM, and the quality of methyl chloride is relatively poor. Moreover, excessive moisture in methyl chloride will also cause corrosion to the equipment used later, reducing the service life of the equipment. Summary of the Invention

[0003] The present invention provides a combined drying tower for removing moisture from methyl chloride, which can greatly improve the water removal efficiency, thereby obtaining methyl chloride with low water content and improving the quality of methyl chloride.

[0004] The present invention adopts the following technical solutions: A combined drying tower for removing moisture from methyl chloride, which includes drying tower I and drying tower II. Drying tower I is a packed tower, and drying tower II is a packed and bubble-cap tower. A wet methyl chloride gas inlet is provided on the side of drying tower I, a gas outlet is provided at the top of drying tower I, packing I is provided in drying tower I, a liquid outlet I is provided at the bottom of drying tower I. One end of the liquid inlet pipeline is a sulfuric acid inlet, and the other end of the liquid inlet pipeline is set as a sulfuric acid outlet and is connected to the liquid inlet I of drying tower I. The liquid outlet I is connected to the main body part of the liquid inlet pipeline through a circulation reflux device I. The lower part of the drying tower II is provided with a feed inlet, which is communicated with the gas outlet at the top of the drying tower I. The top of the drying tower II is provided with a discharge outlet, and the discharge outlet is communicated with the dried methyl chloride gas tank through a drying bottle. Inside the drying tower II, a bubble cap tray, an upper drying chamber and a lower drying chamber are successively arranged from top to bottom. A sulfuric acid inlet is arranged at a position corresponding to the bubble cap tray on the side of the drying tower II. An upper packing is arranged in the upper drying chamber. A liquid collecting area is arranged at the lower part of the upper drying chamber. A sulfuric acid liquid level gauge is arranged on the side of the liquid collecting area. The liquid outlet II on the side of the liquid collecting area is connected with the liquid return port II on the side of the upper drying chamber through a circulation reflux device II. A liquid collecting tray is arranged at the bottom of the liquid collecting area. The inside of the upper drying chamber and the inside of the lower drying chamber are separated by the liquid collecting tray. A lower packing is arranged in the lower drying chamber. A circulation reflux device III is arranged between the liquid outlet III at the bottom of the lower drying chamber and the liquid return port III on the side. The feed inlet is communicated with the inside of the lower drying chamber. An overflow conveying pipe is arranged between the side of the upper drying chamber and the side of the lower drying chamber. One end of the overflow conveying pipe extends into the liquid collecting area, and the other end extends into the lower drying chamber. An electromagnetic valve is arranged on the overflow conveying pipe. A controller is arranged between the sulfuric acid liquid level gauge and the electromagnetic valve. A channel is arranged in the middle of the liquid collecting tray. The inside of the lower drying chamber and the inside of the upper drying chamber are connected through the channel.

[0005] Furthermore, the circulation reflux device I includes a circulation pump I and a collecting bucket I. The liquid outlet I is connected with the inlet of the circulation pump I. The outlet of the circulation pump I is communicated with the inlet of the collecting bucket I. The outlet of the collecting bucket I is communicated with the main part of the liquid inlet pipeline through a conveying pipe I. A drain pipe I is further arranged on the conveying pipe I. A switching valve I is arranged at the joint of the drain pipe I and the conveying pipe I.

[0006] Furthermore, the circulation reflux device II is set as a circulation pump II. The liquid outlet II on the side of the liquid collecting area is connected with the liquid return port II on the side of the upper drying chamber through the circulation pump II.

[0007] Furthermore, for the circulation reflux device III, the circulation reflux device III includes a circulation pump III and a collecting bucket III. The liquid outlet III is connected with the inlet of the circulation pump III. The outlet of the circulation pump III is communicated with the inlet of the collecting bucket III. The outlet of the collecting bucket III is communicated with the liquid return port III through a conveying pipe III. A switching valve III is further arranged on the conveying pipe III.

[0008] Furthermore, the channel is set as a vertical tower-shaped air duct.

[0009] Furthermore, the controller is set as a PLC controller.

[0010] Furthermore, the packing I is set as spherical packing, and both the upper packing and the lower packing are set as spherical packing.

[0011] The present invention has the following beneficial effects: After adopting the technical solution of the present invention, the drying tower II can be transformed without adding a drying tower. The original secondary drying and water removal is changed to tertiary drying and water removal, which increases the effect of removing water from methyl chloride, enabling the water in methyl chloride to be fully removed. The moisture content of methyl chloride can be controlled below 15 PPM, thus greatly improving the water removal efficiency, enhancing the quality of methyl chloride, avoiding corrosion of the equipment used in the later stage, and increasing the service life of the equipment. The cost of the present invention is relatively low during the entire transformation process. The present invention only has a sulfuric acid inlet at a position corresponding to the bubble cap tray on the side of the drying tower II. This sulfuric acid inlet, in combination with a sulfuric acid level gauge, a solenoid valve, and a controller, realizes the supply of sulfuric acid to the upper drying chamber and the lower drying chamber inside the entire drying tower II. This not only makes the supply accurate and does not waste the usage amount of sulfuric acid, but also utilizes the principle of liquid overflow to supply acid to the lower drying chamber. The structure is simple and compact, without the need for major modification of the equipment, and the operation is also convenient. The sulfuric acid solutions in the upper drying chamber and the lower drying chamber of the present invention are respectively circulated for treatment to prevent the influence of different acid concentrations in the two drying chambers on the water removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0013] Figure 1 It is a schematic structural diagram of the present invention. EMBODIMENTS

[0014] The following will elaborate on the preferred embodiments of the present invention in detail with reference to the drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0015] In Figure 1In this invention, a combined drying tower for removing moisture from methyl chloride is provided. It includes drying tower I 1 and drying tower II 2. Drying tower I 1 is a packed tower, and drying tower II 2 is a packed bubble-cap tower. A wet methyl chloride gas inlet 3 is provided on the side of drying tower I 1. A gas outlet 4 is provided at the top of drying tower I 1. Packing I 5 is provided inside drying tower I 1. An outlet I 6 is provided at the bottom of drying tower I 1. One end of the liquid inlet pipeline 7 is a sulfuric acid inlet, and the other end of the liquid inlet pipeline 7 is set as a sulfuric acid outlet and is connected to the inlet I 8 of drying tower I 1. Outlet I 6 is connected to the main part of the liquid inlet pipeline 7 through a circulation reflux device I. A feed inlet 9 is provided at the lower part of drying tower II 2. Feed inlet 9 is connected to the gas outlet 4 at the top of drying tower I 1. A discharge outlet 10 is provided at the top of drying tower II 2. Discharge outlet 10 is connected to a dried methyl chloride gas tank 12 through a drying bottle 11. Inside drying tower II 2, a bubble-cap tray 13, an upper drying chamber 14, and a lower drying chamber 15 are arranged in sequence from top to bottom. A sulfuric acid inlet 16 is provided at a position on the side of drying tower II 2 corresponding to the bubble-cap tray 13. Upper packing 39 is provided inside the upper drying chamber 14. A liquid collection area 17 is provided at the lower part of the upper drying chamber 14. A sulfuric acid liquid level gauge 18 is provided on the side of the liquid collection area 17. The side outlet II 19 of the liquid collection area 17 is connected to the return liquid port II 20 on the side of the upper drying chamber 14 through a circulation reflux device II. A liquid collection tray 21 is provided at the bottom of the liquid collection area 17. The inside of the upper drying chamber 14 and the inside of the lower drying chamber 15 are separated by the liquid collection tray 21. Lower packing 22 is provided inside the lower drying chamber 15. A circulation reflux device III is provided between the outlet III 23 at the bottom of the lower drying chamber 15 and the return liquid port III 24 on the side. Feed inlet 9 is communicated with the inside of the lower drying chamber 15. An overflow delivery pipe 25 is provided between the side of the upper drying chamber 14 and the side of the lower drying chamber 15. One end of the overflow delivery pipe 25 extends into the liquid collection area 17, and the other end of the overflow delivery pipe 25 extends into the lower drying chamber 15. An electromagnetic valve 26 is provided on the overflow delivery pipe 25. A controller 27 is provided between the sulfuric acid liquid level gauge 18 and the electromagnetic valve 26. In this embodiment, the controller 27 is set as a PLC controller. A channel 28 is provided in the middle of the liquid collection tray 21. The inside of the lower drying chamber 15 and the inside of the upper drying chamber 14 are connected through the channel 28. In this embodiment, the channel 28 is set as a vertical tower-shaped air duct. In this embodiment, the circulation reflux device I includes a circulation pump I 29 and a collection bucket I 30. Outlet I 6 is connected to the inlet of the circulation pump I 29, and the outlet of the circulation pump I 29 is connected to the inlet of the collection bucket I 30.The outlet of the collection bucket I 30 is connected to the main body part of the liquid inlet pipeline 7 through the conveying pipe I 31. A drain pipe I 32 is also provided on the conveying pipe I 31. A switching valve I 33 is provided at the junction of the drain pipe I 32 and the conveying pipe I 31. The circulating reflux device II in this embodiment is set as the circulating pump II 34. The side liquid outlet II 19 of the liquid collection area 17 is connected to the liquid return port II 20 on the side of the upper drying chamber 14 through the circulating pump II 34. The circulating reflux device III in this embodiment includes a circulating pump III 35 and a collection bucket III 36. The liquid outlet III 23 is connected to the inlet of the circulating pump III 35. The outlet of the circulating pump III 35 is connected to the inlet of the collection bucket III 36. The outlet of the collection bucket III 36 is connected to the liquid return port III 24 through the conveying pipe III 37. A switching valve III 38 is also provided on the conveying pipe III 37. The packing I 5 in this embodiment is set as spherical packing. Both the upper packing 39 and the lower packing 22 are set as spherical packing.,

[0016] The usage process of the present invention is as follows: When a 98% sulfuric acid solution needs to be input into the drying tower I 1, the sulfuric acid solution is input into the drying tower I 1 through the liquid inlet pipeline 7. Then, the wet chloromethane gas enters the drying tower I 1 from the wet chloromethane gas inlet 3 and is dehydrated through the sulfuric acid and packing I 5 in the drying tower I 1. During the dehydration process, the sulfuric acid is discharged back into the drying tower I 1 through the liquid outlet I 6, the circulation pump I 29, the collection barrel I 30, and the liquid inlet pipeline 7 for recycling to effectively absorb water. When the concentration of the sulfuric acid cannot achieve the dehydration effect, the shut-off valve I 33 can be opened to discharge the waste sulfuric acid from the drain pipe I 32; When a 98% sulfuric acid solution needs to be input into the drying tower II 2, the sulfuric acid solution is discharged into the drying tower II 2 through the sulfuric acid inlet 16. The sulfuric acid solution flows from the upper part of the drying tower II 2 through the upper drying chamber 14 into the liquid collection area 17. Most of the sulfuric acid is stored in the liquid collection area for drying the upper drying chamber 14, and a small part of the sulfuric acid flows through the channel 28 and is stored in the lower drying chamber 15 for standby. When the sulfuric acid level gauge 18 monitors that the sulfuric acid level in the liquid collection area exceeds the specified level, the sulfuric acid level gauge 18 sends a signal to the controller 27, and the controller controls the solenoid valve 26 to open, and the overflowing sulfuric acid is transported through the overflow pipeline 25 to the lower drying chamber 15 for standby. When the sulfuric acid level in the liquid collection area reaches the specified level, the controller 27 closes the solenoid valve 26. After the infusion is completed, the chloromethane gas semi-finished product after the initial water absorption in the drying tower I 1 enters the drying tower II 2 from the gas outlet 4 of the drying tower I 1 through the feed inlet 9 of the drying tower II 2. First, it is dehydrated through the sulfuric acid and lower packing 22 stored in the lower drying chamber 15. After dehydration, it enters the upper drying chamber through the channel 28 and is dehydrated through the sulfuric acid, upper packing 39, and bubble cap tray 13 in the upper drying chamber 15, and then enters the dried chloromethane gas tank 12 after passing through the discharge port 10 at the top of the drying tower II 2 and the drying treatment of the drying bottle 11. During the process of water absorption in the lower drying chamber 15, the switch valve III 38 is opened, and the sulfuric acid is discharged into the lower drying chamber 15 through the liquid outlet III 23, the circulation pump III 35, the collection barrel III 36, and the pipeline III 37 for recycling to effectively absorb water. When the water absorption is completed, the switch valve III 38 is closed, and at the same time, the collection barrel III 36 is opened to discharge the waste liquid with a lower concentration; During the process of water absorption in the upper drying chamber 14, the circulation pump II 34 is opened, and the sulfuric acid is discharged into the upper drying chamber 14 for recycling under the action of the circulation pump.

[0017] Without being limited thereto, any changes or substitutions that can be thought of without creative work shall be covered within the protection scope of the present invention's patent. Therefore, the protection scope of the present invention's patent shall be subject to the protection scope defined by the claims.

Claims

1. A combined drying tower for removing moisture from methyl chloride, characterized in that It includes drying tower I (1) and drying tower II (2). Drying tower I (1) is a packed tower, and drying tower II (2) is a packed bubble-cap tower. A wet methyl chloride gas inlet (3) is provided on the side of drying tower I (1), a gas outlet (4) is provided at the top of drying tower I (1), packing I (5) is provided inside drying tower I (1), a liquid outlet I (6) is provided at the bottom of drying tower I (1), one end of the liquid inlet pipeline (7) is a sulfuric acid inlet, and the other end of the liquid inlet pipeline (7) is set as a sulfuric acid outlet and is connected to the liquid inlet I (8) of drying tower I (1). The liquid outlet I (6) is connected to the main body part of the liquid inlet pipeline (7) through a circulation reflux device I. A feed inlet (9) is provided at the lower part of the drying tower II (2). The feed inlet (9) is connected to the gas outlet (4) at the top of the drying tower I (1). A discharge outlet (10) is provided at the top of the drying tower II (2). The discharge outlet (10) is connected to a dried methyl chloride gas tank (12) through a drying bottle (11). Inside the drying tower II (2), a bubble-cap tray (13), an upper drying chamber (14), and a lower drying chamber (15) are arranged in sequence from top to bottom. A sulfuric acid inlet (16) is provided at a position on the side of the drying tower II (2) corresponding to the bubble-cap tray (13). Upper packing (39) is provided inside the upper drying chamber (14). A liquid collection area (17) is provided at the lower part of the upper drying chamber (14). A sulfuric acid liquid level gauge (18) is provided on the side of the liquid collection area (17). The side liquid outlet II (19) of the liquid collection area (17) is connected to the liquid return port II (20) on the side of the upper drying chamber (14) through a circulation reflux device II. A liquid collection tray (21) is provided at the bottom of the liquid collection area (17). The inside of the upper drying chamber (14) and the inside of the lower drying chamber (15) are separated by the liquid collection tray (21). Lower packing (22) is provided inside the lower drying chamber (15). A circulation reflux device III is provided between the liquid outlet III (23) at the bottom of the lower drying chamber (15) and the liquid return port III (24) on the side. The feed inlet (9) is communicated with the inside of the lower drying chamber (15). An overflow delivery pipe (25) is provided between the side of the upper drying chamber (14) and the side of the lower drying chamber (15). One end of the overflow delivery pipe (25) extends into the liquid collection area (17), and the other end of the overflow delivery pipe (25) extends into the lower drying chamber (15). An electromagnetic valve (26) is provided on the overflow delivery pipe (25). A controller (27) is provided between the sulfuric acid liquid level gauge (18) and the electromagnetic valve (26). A channel (28) is provided in the middle of the liquid collection tray (21). The inside of the lower drying chamber (15) and the inside of the upper drying chamber (14) are connected through the channel (28).

2. The combined drying tower for removing moisture from methyl chloride according to claim 1, characterized in that The described circulation and reflux device I includes a circulation pump I (29) and a collection barrel I (30). The liquid outlet I (6) is connected to the inlet of the circulation pump I (29), the outlet of the circulation pump I (29) is connected to the inlet of the collection barrel I (30), the outlet of the collection barrel I (30) is connected to the main body part of the liquid inlet pipeline (7) through a conveying pipe I (31), a drain pipe I (32) is further provided on the conveying pipe I (31), and a switching valve I (33) is provided at the junction of the drain pipe I (32) and the conveying pipe I (31).

3. The combined drying tower for removing moisture from methyl chloride according to claim 1, characterized in that The described circulation and reflux device II is set as a circulation pump II (34), and the side liquid outlet II (19) of the liquid collection area (17) is connected to the liquid return port II (20) on the side of the upper drying chamber (14) through the circulation pump II (34).

4. The combined drying tower for removing moisture from methyl chloride according to claim 1, characterized in that For the described circulation and reflux device III, the circulation and reflux device III includes a circulation pump III (35) and a collection barrel III (36). The liquid outlet III (23) is connected to the inlet of the circulation pump III (35), the outlet of the circulation pump III (35) is connected to the inlet of the collection barrel III (36), the outlet of the collection barrel III (36) is connected to the liquid return port III (24) through a conveying pipe III (37), and a switching valve III (38) is further provided on the conveying pipe III (37).

5. The combined drying tower for removing moisture from methyl chloride according to claim 1, characterized in that The described channel (28) is set as a vertical tower-shaped air duct.

6. The combined drying tower for removing moisture from methyl chloride according to claim 1, characterized in that The described controller (27) is set as a PLC controller.

7. The combined drying tower for removing moisture from methyl chloride according to claim 1, characterized in that The described packing I (5) is set as spherical packing, and both the upper packing (39) and the lower packing (22) are set as spherical packing.

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