Deacidification device for producing dimethyl phosphite

Abstract

The utility model discloses a deacidification device for producing dimethyl phosphite. The deacidification device comprises a deacidification kettle, a condensing device and an analysis and determination device, a servo variable frequency motor, a feeding port, a backflow port, a vacuum port, an on-line thermometer, an on-line vacuum meter, a radar liquid level meter, a searchlight and a sight glass are arranged on a kettle cover of the deacidification kettle, the on-line liquid level meter, a circulating water interlayer, a stirrer and a discharging port are arranged on a kettle body, and the feeding port and the discharging port are communicated with a feeding pipeline and a discharging pipeline through an on-line flowmeter and an electromagnetic valve respectively. The vacuum port communicates with a vacuum pipeline; the condensing device is arranged above the deacidification kettle and comprises two condensers which are connected in series, one condenser is connected with a vacuum pipeline, the other condenser is used for discharging condensed gas, and a condensate outlet is connected with the reflux inlet; the analyzing and measuring device comprises a crude ester content acidity measuring device A mounted on the feeding pipeline and a crude ester content acidity measuring device B mounted on the kettle cover; the device disclosed by the utility model has the advantages of high working efficiency, low product acidity, high production yield and high automation degree.

Description

Technical Field

[0001] The utility model belongs to the technical field of dimethyl phosphite production equipment, and particularly relates to a deacidification device for producing dimethyl phosphite. Background Technique

[0002] Dimethyl phosphite is an important product in fine chemical industry and has a very wide range of uses. It is not only an intermediate for producing pesticides such as glyphosate, trichlorfon, kitazin, omethoate, etc., but also a raw material for organic phosphorus corrosion inhibitors, dye additives, plastic auxiliaries and flame retardants. It can be used to synthesize water treatment agents and can also be used as a methylation reagent for synthesizing products such as quaternary ammonium salt bactericides, antistatic agents, and softeners.

[0003] With the rise of the domestic herbicide industry, the output of glyphosate has been increasing day by day. As a raw material for producing glyphosate, the demand for dimethyl phosphite is also increasing, and the quality requirements are getting higher and higher. At present, the most common method for industrial synthesis of dimethyl phosphite in China is to use methanol and phosphorus trichloride as raw materials and carry out synthesis under certain conditions, which is relatively simple and easy to operate. In the production process of dimethyl phosphite, after phosphorus trichloride and methanol react in contact with each other, by-products mainly composed of hydrogen chloride and chloromethane will be generated, and it is necessary to separate them to reduce the acidity and impurities of the product dimethyl phosphite, and at the same time reduce the occurrence of side reactions. Therefore, deacidification treatment is required. The current deacidification methods are mostly kettle type, but in actual production, the deacidification process is often not complete. Kettle deacidification is discontinuous and inefficient. Under vacuum conditions, the product will be carried away, resulting in low yield. The on-site production automation level is low, and manual sampling and analysis are often required. The acidity of the finished dimethyl phosphite is relatively high, and the quality of the finished product is not high, which has always been the main problem affecting the production of dimethyl phosphite. Therefore, it is necessary to change the production mode, improve the deacidification device, and solving the deacidification problem in the production process of dimethyl phosphite is related to the quality and output of dimethyl phosphite products. Therefore, it is particularly important to improve the deacidification device of dimethyl phosphite. Content of the Utility Model

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a deacidification device for producing dimethyl phosphite with high working efficiency, low product acidity, high production yield, and high automation level.

[0005] The purpose of the utility model is achieved as follows: A deacidification device for producing dimethyl phosphite includes a deacidification kettle, a condensation device, and an analysis and determination device;

[0006] The deacidification kettle includes a kettle cover and a kettle body. The kettle cover is provided with a servo variable-frequency motor, a feed inlet, a reflux port, a vacuum port, an on-line thermometer, an on-line vacuum gauge, a radar level gauge, a searchlight and a sight glass. The side wall of the kettle body is provided with an on-line level gauge and a circulating water interlayer. A stirrer is arranged inside the kettle body. The bottom of the kettle body is provided with a discharge port. The feed inlet is communicated with a feed pipeline through an on-line flowmeter A and a solenoid valve A. The discharge port is communicated with a discharge pipeline through an on-line flowmeter B and a solenoid valve B. The vacuum port is communicated with a vacuum pipeline through a solenoid valve C;

[0007] The condensation device is arranged above the deacidification kettle and includes two condensers connected in series. One of them is connected to the vacuum pipeline, and the other discharges the condensed gas. The condensate outlets at the lower ends of the two condensers are both connected to the reflux port;

[0008] The analysis and determination device includes a crude ester content and acidity determination device A installed on the feed pipeline and a crude ester content and acidity determination device B installed on the kettle cover;

[0009] The servo variable-frequency motor, the on-line flowmeter A, the on-line flowmeter B, the solenoid valve A, the solenoid valve B, the solenoid valve C, the crude ester content and acidity determination device A and the crude ester content and acidity determination device B are all connected to a remote control system.

[0010] Preferably, the stirring blades of the stirrer are of the anchor frame type.

[0011] Preferably, there are two symmetrical sight glasses on the edge of the kettle cover, and a searchlight is arranged above one of the sight glasses.

[0012] Preferably, multiple deacidification kettles can be used in series to form a multi-stage deacidification kettle.

[0013] Preferably, the condenser is made of graphite material, and the condensation medium is frozen brine.

[0014] Preferably, the circulating water interlayer is provided with heating or cooling medium inlets and outlets. The inlet is arranged at the lower part of one side of the kettle body, and the outlet is arranged at the upper part of the other side of the kettle body.

[0015] Preferably, solenoid valves D are arranged at both the heating or cooling medium inlets and outlets, and the two solenoid valves D are both connected to the remote control system.

[0016] Due to the above technical solutions, the beneficial effects of the present utility model are as follows: The present utility model adopts a deacidification kettle, a condensation device and an analysis and determination device to successively perform crude ester deacidification treatment on the esterification reactants for producing dimethyl phosphite, condense and recover dimethyl phosphite, and detect the acidity of the crude ester content during feeding and discharging. It can effectively reduce the acidity of the dimethyl phosphite product while increasing the production yield. Moreover, through the comparative detection of the acidity during feeding and discharging, the process parameters can be adjusted and controlled in a timely manner to effectively ensure the smooth progress of the deacidification work. The present utility model adopts a stirrer, a circulating water interlayer, and driving and detection instruments such as an on-line thermometer, an on-line vacuum gauge, and an on-line flowmeter, and connects each driving and detection instrument to a remote control system, which can effectively ensure the process index requirements of the deacidification kettle, further ensure the smooth progress of the deacidification work while improving the working efficiency of the entire device. The present utility model adopts an on-line liquid level gauge and a radar liquid level gauge to double-determine the materials, which can make the detection results more accurate and further ensure the working efficiency of the entire device. Generally, the present utility model has the advantages of high working efficiency, low product acidity, high production yield, and high automation degree. Brief Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the composition of the present utility model.

[0018] In the figure: 1. Kettle cover; 2. Sight glass; 3. On-line thermometer; 4. On-line vacuum gauge; 5. Crude ester content acidity determination device B; 6. Stainless steel protective net; 7. Servo frequency conversion motor; 8. Radar liquid level gauge; 9. Solenoid valve C; 10. Crude ester content acidity determination device A; 11. Feed pipeline; 12. Solenoid valve A; 13. On-line flowmeter A; 14. Searchlight; 15. Vacuum pipeline; 16. Follow-up treatment and vacuum generating device; 17. Condenser; 18. Condensate outlet; 19. Outlet; 20. Return port; 21. Feed port; 22. Vacuum port; 23. Stirrer; 24. Kettle body; 25. Discharge pipeline; 26. On-line flowmeter B; 27. Solenoid valve B; 28. Discharge port; 29. Inlet; 30. Solenoid valve D; 31. On-line liquid level gauge. Detailed Embodiments

[0019] The technical solutions of the present utility model will be further specifically described below with reference to the drawings.

[0020] As Figure 1 shown, the present utility model provides a deacidification device for producing dimethyl phosphite, which is mainly used to solve problems such as low deacidification efficiency, high acidity, low yield, and low automation degree in the production of dimethyl phosphite, and is used for deacidification treatment of the products after the esterification reaction.

[0021] This utility model is used for the deacidification process in the production of dimethyl phosphite. This device mainly deacidifies the esterification reactants after the reaction of methanol and phosphorus trichloride. The described device includes a deacidification kettle, a condensation device, and an analysis and determination device.

[0022] The described deacidification kettle includes a kettle cover 1 and a kettle body 24, made of glass-lined steel. A stirrer 23 is installed on the kettle cover 1, powered by a servo variable-frequency motor 7, equipped with a stainless-steel protective net 6, and connected to a remote control system, enabling on-site control and remote adjustment control.

[0023] The side wall of the kettle body 24 of the described deacidification kettle has a circulating water interlayer. Heating or condensing medium inlets and outlets are respectively arranged on the circulating water interlayer. The inlet 29 is located at the lower side of the deacidification kettle body 24, and the outlet 19 is located at the upper side of the deacidification kettle body 24.

[0024] The stirrer 23 of the described deacidification kettle is rotatably fixed on the kettle cover 1 of the deacidification kettle. The connection between the kettle cover 1 and the kettle body 24 is fixed by bolts around, with a gasket in the middle. The stirring blades of the stirrer 23 are of the anchor frame type.

[0025] The kettle cover 1 of the described deacidification kettle is provided with a feed inlet 21, a vacuum port 22, a reflux port 20, and a sight glass 2. An on-line liquid level gauge 31 is installed on the side wall of the kettle body 24. A discharge port 28 is arranged at the bottom of the kettle body 24. The pipelines connecting the feed inlet 21 and the discharge port 28 are made of PP material or lined with tetrafluoro material, preferably PP material. An electromagnetic valve A12 and an on-line flowmeter A13 are installed on the feed pipeline 11 connecting the feed inlet 21. An electromagnetic valve B27 and an on-line flowmeter B26 are installed on the discharge pipeline 25 connecting the discharge port 28, and are connected to a remote control system. The vacuum port 22 is connected to a vacuum pipeline 15, and the material of the vacuum pipeline 15 is PVC.

[0026] The described deacidification kettle can be used in multiple series to form a multi-stage deacidification kettle, with continuous feeding and discharging, and continuous multi-stage deacidification treatment of the esterification reactants.

[0027] The condensation device is located above the deacidification kettle. The input end is connected to the vacuum pipeline 15, and the output end is externally connected to a subsequent treatment and vacuum generating device 16. The main body of the condensation device is a condenser 17. This device mainly uses two condensers 17 in series to condense the dimethyl phosphite carried out by vacuum, and returns it to the reflux port 20 of the deacidification kettle through the condensate outlet 18, reducing the loss of finished dimethyl phosphite during the deacidification process of crude ester. The material of the condenser 17 can be graphite material or other acid-resistant alloy materials, preferably graphite material, and the condensing medium is chilled brine.

[0028] The described analysis and measurement device mainly includes the crude ester content acidity measurement device A installed on the feed pipeline 11 and the crude ester content acidity measurement device B installed on the bottom of the column. An online thermometer 3, an online vacuum gauge 4, and a radar level gauge 8 are also installed on the bottom of the column. The analysis and measurement instruments included in the analysis and measurement device adopt a digital display mode and all have remote transmission functions. They accurately analyze and measure the incoming and outgoing materials respectively, and transmit the analysis and measurement results to the DCS computer of the remote control system. It can realize remote control of each solenoid valve through the DCS computer, thereby adjusting the on-site production conditions. And by setting process index limits, an alarm will be immediately issued when the limits are exceeded to ensure production safety.

[0029] Among them, the crude ester content acidity measurement device is an online chromatograph dedicated to detecting dimethyl phosphite. After being purchased from the market, it is installed on the deacidification kettle and can automatically sample and analyze at regular intervals and report the results.

[0030] After the above installation is completed, the present utility model can be put into use. The esterification reactant is added into the deacidification kettle from the feed port 21, and each component of the deacidification kettle is started to work. The material completes the deacidification treatment in the deacidification kettle. The gas during the treatment process is discharged from the vacuum port 22 through the vacuum pipeline into the condensation device, and the condensation treatment is completed in the condensation device. The condensed liquid flows back to the deacidification kettle for reuse, and the condensed gas enters the subsequent treatment. The material after the deacidification treatment is discharged from the discharge port 28. During this period, the online thermometer 3 and the circulating water interlayer provide a qualified temperature working environment for the deacidification kettle. During this period, the online vacuum gauge 5 and the vacuum generating device provide a qualified vacuum working environment for the deacidification kettle. During this period, the online level gauge 31 and the radar level gauge 8 provide double detection for the material level in the deacidification kettle. During this period, two online flow meters provide flow detection for the materials entering and leaving the deacidification kettle. During this period, two crude ester content acidity measurement devices provide crude ester content acidity detection for the materials entering and leaving the deacidification kettle. During this period, the online thermometer 3, the circulating water interlayer, the online vacuum gauge 5, the vacuum generating device, the online level gauge 31, the radar level gauge 8, two online flow meters, and two crude ester content acidity measurement devices, etc., under the unified coordination of the remote control system, automatically feed and discharge materials and automatically and continuously carry out the deacidification treatment work of the esterification reactant and the recycling work of vacuum-bringing out dimethyl phosphite.

[0031] In summary, the present utility model can effectively solve the problems of low deacidification efficiency, high acidity, low yield, and low automation degree in the deacidification process during the production of dimethyl phosphite, reduce manual on-site operations and analysis and measurement, be safer in operation, more accurate in analysis, save labor, have a high degree of automation, and greatly improve the production efficiency of dimethyl phosphite.

[0032] The utility model redesigned the dimethyl phosphite deacidification device. The device includes a deacidification kettle, a condensation device and an analysis and determination device. The main components include a stirrer 23, a condenser 17, multiple solenoid valves, multiple online flow meters, two crude ester content and acidity determination devices, an online vacuum gauge 4, an online thermometer 3, a radar level gauge 8, etc. Using this device to deacidify the esterification reactants greatly improves the production efficiency and product quality.

[0033] The analysis and determination device in this device includes two crude ester content and acidity determination devices, an online thermometer 3, an online vacuum gauge 4, a radar level gauge 8 and two online flow meters, etc. All of them adopt a digital display mode, with more precise control, and transmit the analysis and determination results to the DCS computer. It can realize remotely controlling each solenoid valve through the DCS computer to adjust the on-site production conditions, and set process index limits. An alarm will be immediately issued when the limit is exceeded, and problems can be immediately handled and solved. The reaction time is short and the automation degree is high.

[0034] The condensation device in this device uses two graphite condensers in series, which is used to condense the dimethyl phosphite carried out by vacuum and reflux it to the deacidification kettle, reducing the loss of the finished dimethyl phosphite in the process of crude ester deacidification and improving the yield.

[0035] The deacidification kettle in this device can be used in multiple series to form a multi-stage deacidification kettle, with continuous feeding and discharging, and continuously carry out multi-stage deacidification treatment on the esterification reactants, greatly improving the work efficiency.

[0036] The condenser 17 in this device is made of graphite material, reducing the corrosion of hydrogen chloride to the equipment and greatly improving the service life.

[0037] The stirrer 23 installed on the deacidification kettle in this device is powered by a servo variable-frequency motor, equipped with a stainless steel protective net 6, and connected to a remote control system, which can realize on-site control and remote adjustment control, with more convenient adjustment and safer use.

[0038] The deacidification kettle in this device is installed with a radar level gauge 8, which is not affected by the material for liquid level measurement, and double-measures the material liquid level with an online level gauge 31, eliminating the liquid level error caused by the material characteristics, and the measurement result is more accurate.

[0039] This device is installed with two crude ester content and acidity determination devices, no longer requiring manual sampling and analysis, saving labor.

[0040] The above is only the preferred embodiment of the utility model and is not intended to limit the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A deacidification device for producing dimethyl phosphite, characterized in that: It includes a deacidification kettle, a condensation device and an analysis and measurement device; The deacidification kettle comprises a kettle cover and a kettle body, the kettle cover is provided with a servo frequency conversion motor, a feed port, a reflux port, a vacuum port, an online thermometer, an online vacuum gauge, a radar level gauge, a searchlight and a sight glass, the side wall of the kettle body is provided with an online level gauge and a circulating water interlayer, the kettle body is provided with an agitator, the bottom of the kettle body is provided with a discharge port, the feed port is connected to the feed pipeline through an online flow meter A and a solenoid valve A, the discharge port is connected to the discharge pipeline through an online flow meter B and a solenoid valve B, and the vacuum port is connected to the vacuum pipeline through a solenoid valve C; The condensing device is arranged above the deacidification kettle, and comprises two condensers connected in series, one of which is connected to the vacuum pipe, and the other discharges condensed gas, and the condensate outlets at the lower ends of the two condensers are connected to the reflux port; The analytical and measuring device comprises a crude ester content acidity measuring device A installed on the feed pipe and a crude ester content acidity measuring device B installed on the kettle cover; The servo variable frequency motor, the online flow meter A, the online flow meter B, the solenoid valve A, the solenoid valve B, the solenoid valve C, the crude ester content acidity determination device A and the crude ester content acidity determination device B are all connected to a remote control system.

2. The deacidification device for producing dimethyl phosphite according to claim 1, characterized in that: The stirring blades of the stirrer are of anchor frame type.

3. The deacidification device for producing dimethyl phosphite according to claim 1, characterized in that: Two symmetrical viewing mirrors are arranged on the edge of the kettle cover, and the searchlight is arranged above one of the viewing mirrors.

4. The deacidification device for producing dimethyl phosphite according to claim 1, characterized in that: The deacidification kettles can be used in series to form a multi-stage deacidification kettle.

5. The deacidification device for producing dimethyl phosphite according to claim 1, characterized in that: The condenser is made of graphite, and the condensing medium is frozen salt water.

6. The deacidification device for producing dimethyl phosphite according to claim 1, characterized in that: The circulating water interlayer is provided with an inlet and outlet for a heating or cooling medium, wherein the inlet is arranged below one side of the kettle body, and the outlet is arranged above the other side of the kettle body.

7. The deacidification device for producing dimethyl phosphite according to claim 6, characterized in that: The inlet and outlet of the heating or cooling medium are both provided with solenoid valves D, and both solenoid valves D are connected to a remote control system.

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