CN218590523U

CN218590523U - Deacidification device for producing dimethyl phosphite

Info

Publication number: CN218590523U
Application number: CN202222779286.0U
Authority: CN
Inventors: 张庆华; 杨超; 张妍; 田义群; 彭春雪; 胡波; 覃立忠; 刘三六; 胡付超
Original assignee: Hubei Three Gorges Laboratory; Institute of Process Engineering of CAS; Hubei Taisheng Chemical Co Ltd
Current assignee: Hubei Three Gorges Laboratory; Institute of Process Engineering of CAS; Hubei Taisheng Chemical Co Ltd
Priority date: 2022-10-21
Filing date: 2022-10-21
Publication date: 2023-03-10
Anticipated expiration: 2032-10-21

Abstract

The utility model discloses a deacidification device for producing dimethyl phosphite. Including motor, gas outlet, pivot, steam outlet, get rid of dish, reaction liquid export, steam inlet, collector tube, press from both sides cover and reaction liquid entry, its characterized in that: the deacidification device is composed of more than two stages of reducing flail discs, the diameter of the flail disc is gradually reduced from top to bottom along the deacidification device, and a liquid collecting pipe is arranged on the inner wall surface of the deacidification device above the side of each stage of the flail disc. The utility model discloses a deacidification device and application method have adopted multistage reducing flail disk, have prevented to appear the ditch flow and the dry wall phenomenon that deacidification device lower half appears because of deacidification in-process stock solution reduces gradually, and the liquid film distributes more evenly, has improved hydrogen chloride desorption efficiency and dimethyl phosphite's yield and quality. Meanwhile, the steam consumption is effectively reduced by the design that the inner diameter of the deacidification device is gradually reduced from top to bottom.

Description

Deacidification device for producing dimethyl phosphite

Technical Field

The utility model relates to a fine chemistry industry technical field, concretely relates to deacidification device for producing dimethyl phosphite.

Background

Dimethyl phosphite, also known as dimethyl phosphite, is an important raw material for producing pesticides such as insecticide, trichlorfon, dichlorvos and glyphosate, and can also be used for producing plastic additives, dye additives, flame retardants and the like.

At present, dimethyl phosphite is industrially obtained mainly by taking methanol and phosphorus trichloride as raw materials and adopting a solvent-free continuous production process. The production process has the advantages of high production speed, low production cost and low operation cost. However, during the production process, a large amount of hydrogen chloride and methyl chloride are generated while the methyl phosphite is generated by the reaction of the methanol and the phosphorus trichloride, and the methyl phosphite and the methyl chloride are easily generated by side reaction after the dimethyl phosphite is contacted with the hydrogen chloride for a long time, thereby influencing the yield and the quality of the dimethyl phosphite. In order to improve the yield and purity of the dimethyl phosphite and reduce the occurrence of side reactions, the hydrogen chloride needs to be removed from the reaction liquid in time. Therefore, the deacidification process in the production process of dimethyl phosphite is one of the key steps for determining the yield and quality of dimethyl phosphite. The existing dimethyl phosphite production enterprises mainly adopt a one-stage/multi-stage flail disk deacidification device to carry out deacidification, and the yield and the purity of the prepared dimethyl phosphite are lower.

The patent CN 101870712B provides a method for producing dimethyl phosphite, phosphorus trichloride and methanol with a molar ratio of 1 (3.0 to 3.1) are respectively and continuously injected by respective injection structures through respective corresponding pumping mechanisms to be fed into a reaction cavity space for mutual mixing reaction, then reaction materials are introduced into a centrifugal cyclone separation device with the pressure lower than the reaction cavity space along the tangential direction, so that non-condensable gas and a condensed liquid product are subjected to centrifugal cyclone separation, and the collected liquid material is dimethyl phosphite. The method can quickly complete the separation of the product, effectively reduce the side reaction of the hydrogen chloride and the dimethyl phosphite, and improve the yield and the quality of the product. Patent CN114605469A discloses a production process for efficiently synthesizing dimethyl phosphite, which adopts a continuous grading reaction mode, after phosphorus trichloride is added, methanol is added in a batch injection mode for reaction, hydrogen chloride and methyl chloride are discharged from a vacuum tube, and after deacidification and rectification, dimethyl phosphite is prepared. The production process can discharge products such as hydrogen chloride and the like at a higher speed, reduces the generation of byproducts and improves the yield of dimethyl phosphite.

Although the production process/device accelerates the removal rate of hydrogen chloride to a certain extent and improves the yield of dimethyl phosphite, the production process/device still has the problems of high steam consumption, incomplete hydrogen chloride removal and low yield and purity of dimethyl phosphite.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a deacidification device for producing dimethyl phosphite for solving the problems. The deacidification device is used in the production process of dimethyl phosphite, and can improve the removal efficiency of hydrogen chloride and the yield and quality of dimethyl phosphite while reducing the steam consumption.

The utility model provides a deacidification device for producing dimethyl phosphite, include motor, gas outlet, pivot, steam outlet, get rid of the dish, get rid of a dish hole, reaction liquid export, steam inlet, collector tube, steam jacket and reaction liquid entry.

The deacidification device is composed of more than two stages of throwing discs, the diameter of each throwing disc is gradually reduced from top to bottom along the deacidification device, and a liquid collecting pipe is arranged on the inner wall surface of the deacidification device above the side of each stage of throwing disc.

The ratio of the diameter of the throwing disc to the inner diameter of the deacidification device is 0.2-0.9, and the inner diameter of the deacidification device is gradually reduced from top to bottom.

The deacidification device is composed of three stages of throwing disks, the diameters of the throwing disks are sequentially 2.0-1.8m, 1.8-1.6m and 1.6-1.4m from top to bottom and are gradually reduced.

A throwing disc hole is formed in the side wall surface of the throwing disc; the shape of the flail disc hole comprises a circle, a rectangle or a polygon; the aperture of the disc throwing hole is 0.5-10 mm.

The liquid collecting pipe is shaped as an inverted round table, and the included angle between the liquid collecting pipe and the inner wall surface of the deacidification deviceαThe temperature is 20 to 70 degrees.

Compared with the prior deacidifying device, the utility model discloses a deacidifying device has reduced the required heat transfer area among the deacidifying process because the internal diameter reduces from last to down gradually, therefore has reduced the quantity of steam under keeping the same deacidifying temperature.

In the deacidification process of dimethyl phosphite, reaction liquid obtained after reaction of phosphorus trichloride and methanol enters a deacidification device, and a liquid film is formed on the inner wall surface of the deacidification device after centrifugal disc separation. Under the action of gravity, the liquid film moves downwards along the inner wall surface, and hydrogen chloride gas in the liquid film is removed after heat exchange with the wall surface, so that the control of the temperature in the deacidification device is very important. The removal rate of the hydrogen chloride can be slowed down when the temperature is too low, and the side reaction of the dimethyl phosphite and the hydrogen chloride can be caused when the temperature is too high, so that the yield of the dimethyl phosphite is reduced. The purpose of maintaining the negative pressure of the deacidification device is to timely pump out the generated hydrogen chloride gas and avoid side reaction, so that the negative pressure also determines the removal rate of the hydrogen chloride and the final yield of the dimethyl phosphite. Although the excessive negative pressure in the deacidification device is favorable for timely discharging the hydrogen chloride gas from the deacidification device and avoiding the side reaction, the hydrogen chloride gas discharged by the excessive negative pressure can carry a large amount of dimethyl phosphite, thereby reducing the yield of the dimethyl phosphite. And the negative pressure is too small, so that the generated hydrogen chloride gas cannot be discharged in time, the side reaction is caused between the hydrogen chloride gas and dimethyl ester, and the yield of the dimethyl ester is reduced. The disc is thrown in the effect makes the feed liquid after the reaction form even liquid film on deacidification device internal face after the disc centrifugation, and then desorption hydrogen chloride, and the rotational speed of pivot has decided the film forming effect in the deacidification process, and then has decided the desorption efficiency of hydrogen chloride, and lower rotational speed can lead to the film forming effect not good, influence hydrogen chloride desorption efficiency. Higher rotational speeds are advantageous for hydrogen chloride removal, but lead to higher energy consumption.

The utility model discloses a deacidification device for producing dimethyl phosphite has adopted multistage reducing to get rid of the dish, gets rid of the dish from last diameter to reducing down gradually, has prevented to appear the ditch flow and the dry wall phenomenon that deacidification device lower half appears because of the gradual reduction of material liquid among the evaporation process, and the liquid film distributes more evenly, has improved hydrogen chloride desorption efficiency and dimethyl phosphite's yield and quality when reducing steam consumption, but wide application in fields such as chemical industry, pharmacy and water treatment.

Drawings

Figure 1 is a schematic structural diagram of the deacidification device for dimethyl phosphite of the utility model.

Fig. 2 is a schematic view of the throwing disk structure of the present invention.

FIG. 3 is a schematic view of the structure of the header.

FIG. 4 is a schematic structural diagram of a conventional deacidification device for dimethyl phosphite.

Reference numerals

1. Motor, 2, gas outlet, 3, rotating shaft, 4, steam outlet, 5, throwing disc, 51, throwing disc hole, 6, reaction liquid outlet, 7, steam

Inlet, liquid collecting pipe 8, steam jacket 9, reaction liquid inlet 10, inner wall of deacidifying apparatus 11,αthe liquid collecting pipe forms an included angle with the inner wall of the deacidification device.

Detailed Description

Example 1

As shown in fig. 1, a deacidification device for producing dimethyl phosphite comprises a motor 1, a gas outlet 2, a rotating shaft 3, a steam outlet 4, a throwing disc 5, a reaction liquid outlet 6, a steam inlet 7, a liquid collecting pipe 8, a jacket 9 and a reaction liquid inlet 10, wherein a three-stage throwing disc 5 is arranged in the deacidification device, the diameter of the upper part of the deacidification device is 2 m, the diameter of the bottom part of the deacidification device is 1.2 m, the height of the deacidification device is 3.5 m, the diameters of the first, second and third throwing discs are 1.8m, 1.6m and 1.4m respectively, and a plurality of 5 mm circular throwing disc holes 51 are uniformly distributed on the side wall surface of the throwing disc 5. A liquid collecting pipe 8 is arranged on the inner wall surface of the deacidification device above the side of each-stage throwing disc 5, and the included angle between the liquid collecting pipe 8 and the inner wall of the deacidification deviceαIs 45 degrees.

The deacidification device is externally provided with a steam jacket 9, the lower part of the steam jacket 9 is provided with a steam inlet 7, and the upper part of the steam jacket is provided with a steam outlet 4. Deacidifying device upper portion is provided with reaction liquid entry 10, and the deacidifying device top is provided with gas outlet 2, and the deacidifying device bottom is provided with the reaction liquid export. The inevitable deacidification device is provided with an electrode 1 and a driven rotating shaft 3.

The dimethyl phosphite deacidification process performed by adopting the device comprises the following steps:

firstly, a vacuum pump connected with a deacidification device is opened to ensure that the pressure in the kettle reaches-0.075 MPa. And starting the motor, and adjusting the rotating speed of the rotating shaft to be 500 rpm. Regulating the steam flow of the steam inlet 7 to make the temperature in the deacidification device about 75 ℃ until the pressure, the rotating speed and the temperature are stable;

secondly, reaction liquid obtained after the reaction of phosphorus trichloride and methanol enters a deacidification device through a reaction liquid inlet 10 for deacidification, a liquid film is formed on the inner wall of the deacidification device after the reaction liquid is centrifuged by a first-stage throwing disc, the liquid film drops to a certain height along the inner wall surface under the action of gravity, and then the liquid material is collected by a liquid collecting pipe 8 to be further centrifuged, filmed and deacidified by a second-stage throwing disc and a third-stage throwing disc. Collecting the deacidified crude ester to a rectifying tank, and rectifying to obtain the refined dimethyl phosphite.

The process for reacting phosphorus trichloride with methanol comprises the following steps: respectively and continuously spraying 1mol/L phosphorus trichloride and 3mol/L methanol solution into an esterification reaction kettle through respective spraying structures by corresponding pumping mechanisms, and carrying out mutual mixing reaction, wherein the flow rates of the phosphorus trichloride and the methanol are both 50L/min.

The experiment shows that the purity of the dimethyl phosphite is 99.2 percent, the yield is 98.6 percent, and each ton of dimethyl phosphite consumes 0.095 ton of steam in the deacidification process. Compared with the prior deacidification device (comparative example 1), the purity and the yield of the dimethyl phosphite are respectively improved by 2.79 percent and 2.92 percent, and the steam consumption is reduced by 13.64 percent.

Comparative example 1

As shown in the device of figure 4, the diameter of the deacidification device is 2 m, the height is 3.5 m, the inside of the deacidification device is provided with a third-level throwing disc, the diameters of the first-level throwing disc, the second-level throwing disc and the third-level throwing disc are 1.8m, a liquid collecting pipe is not arranged in the device, and other conditions are the same as those of the embodiment 1. The experiment proves that the purity of the dimethyl phosphite is 96.5 percent, the yield is 95.8 percent, and 0.11 ton of steam is consumed by each ton of dimethyl phosphite in the deacidification process.

Claims

1. Production dimethyl phosphite's deacidification device, including motor (1), gas outlet (2), pivot (3), steam outlet (4), gets rid of dish (5), reaction liquid export (6), steam inlet (7), collector tube (8), steam jacket (9) and reaction liquid entry (10), its characterized in that: the deacidification device is composed of more than two stages of throwing disks (5), the diameter of each throwing disk (5) is gradually reduced from top to bottom along the deacidification device, and a liquid collecting pipe (8) is arranged on the inner wall surface of the deacidification device above the side of each throwing disk (5).

2. The deacidification apparatus for producing dimethyl phosphite according to claim 1, wherein: the ratio of the diameter of the throwing disc (5) to the inner diameter of the deacidification device is 0.2 to 0.9, and the inner diameter of the deacidification device is gradually reduced from top to bottom.

3. The deacidification apparatus for producing dimethyl phosphite according to claim 2, wherein: the deacidification device is composed of three stages of throwing disks (5), and the diameters of the throwing disks (5) are sequentially 2.0-1.8m, 1.8-1.6m and 1.6-1.4m from top to bottom and are gradually reduced.

4. The deacidification device for producing dimethyl phosphite according to claim 1, characterized in that: the side wall surface of the throwing disc (5) is provided with a throwing disc hole (51); the shape of the flail disc hole (51) comprises a circle, a rectangle or a polygon; the aperture of the disc throwing hole (51) is 0.5-10 mm.

5. The deacidification apparatus for producing dimethyl phosphite according to claim 1, wherein: the liquid collecting pipe (8) is in the shape of an inverted round table, and the included angle between the liquid collecting pipe (8) and the inner wall surface of the deacidification deviceαThe temperature is 20 to 70 degrees.