Anti-clogging reaction apparatus and method

Abstract

The application discloses an anti-blocking reaction device and method, and relates to the technical field of organic phosphorus chemical industry. The application comprises a reaction kettle, a circulating pump, a cooler, a condenser, a cold trap, an esterate tank and an adsorber; the esterate tank discharge port is connected with the esterate inlet of the reaction kettle through a pipeline; the reaction kettle, the circulating pump, the cooler and the condenser are sequentially connected through pipelines to form a cooling circulation loop; the pipeline section between the circulating pump and the cooler is connected with the reaction kettle through a pipeline to form a material mixing circulation loop; the material mixing circulation loop is connected with the cooling circulation loop through a back feeding valve; the condenser, the cold trap and the adsorber are sequentially connected through pipelines, and the bottom of the adsorber is connected with the cold trap through a pipeline to form a condensation loop. Through the cooperation of the structures, the application can effectively prevent the aldehyde from being polymerized to form solid to block the condensation pipe during the reaction process, ensures the normal production, reduces the maintenance time and improves the utilization rate of the equipment.

Description

Technical Field

[0001] This invention relates to the field of organophosphorus chemical technology, specifically to a reaction apparatus and method for preventing clogging. Background Technology

[0002] Phosphonates contain CP bonds in their molecular structure, exhibiting excellent chemical stability. They are primarily used as highly efficient flame retardants for organic polymers and as highly efficient, low-toxicity, broad-spectrum insecticides. The synthesis of phosphonates mainly uses phosphites as raw materials, obtained through Arbuzov rearrangement and addition reactions.

[0003] The reaction of phosphites with aldehydes is usually carried out at reflux temperature. A traditional reflux reaction apparatus is shown in the figure. Figure 1 As shown; first, the aldehyde is added to reaction vessel 1 and heated to a suitable reaction temperature, then phosphite is added dropwise. This apparatus has many problems and cannot meet the needs of researching and producing downstream products of phosphite; the reasons are as follows: 1. Aldehydes are extremely unstable and readily polymerize, especially under heat. Polymerization inhibitors are usually added to the reaction mixture to solve the polymerization problem. Common polymerization inhibitors include ammonium acetate, triammonium citrate, and compounds or polymers containing a large number of hydroxyl groups or compounds containing a large number of amino groups. Most of these polymerization inhibitors are high-boiling-point substances or solids, which are difficult to remove after the reaction. 2. Because Figure 1 The reflux reaction process is carried out directly in cooler 3. During the reflux reaction, the aldehyde is heated and vaporized or volatilized and escapes into the gas phase. It is separated from the polymerization inhibitor and polymerizes in the gas phase, generating a white solid that adheres to the inner wall of the condenser tube, causing blockage of cooler 3. It often needs to be stopped halfway, which seriously interferes with the normal operation of the test and production. 3. If the condenser tube becomes blocked, it cannot transfer heat normally, which can easily cause safety accidents. This is because the reaction between phosphite and aldehyde and the polymerization reaction of aldehyde itself are both strongly exothermic reactions that release a large amount of heat. The reactants must be cooled down in time. Otherwise, the temperature rise will produce a large number of side reactions, or even cause an explosion and safety accident. 4. In addition, traditional reaction devices also have the following disadvantages and deficiencies: (1) The tail gas of the ester tank 6 and the synthesis tail gas contain toxic and harmful raw materials and by-products such as phosphites and aldehydes, which are directly emitted and pollute the environment, which does not meet the requirements of today's environmental protection; (2) Too much polymerization inhibitor is mixed into the downstream products, affecting the quality of the downstream products and their storage stability.

[0004] Currently, there is no satisfactory reaction device suitable for intermittent and semi-continuous operation that prevents polymerization blockage in the reaction of phosphites with aldehydes to synthesize phosphonates. Therefore, it is necessary to research and design a new type of reaction device that prevents polymerization blockage, eliminates safety hazards, meets environmental protection requirements, and improves product quality.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] To address the aforementioned technical problems, embodiments of the present invention provide an anti-clogging reaction apparatus and method to solve the problems mentioned in the background art.

[0007] I. Design concept of the invention: 1. In this invention, the reactor, circulating pump, cooler, and condenser are connected in series through pipelines to form a cooling circulation loop. This connection method is intended to enable external circulation cooling of the reactants, allowing the cold materials to directly contact the hot material vapor in a countercurrent flow, causing the vapor to liquefy and flow back, removing the heat released by the reaction. At the end of a batch production, the materials in the cooler flow back to the reactor, avoiding residue in the external circulation loop and preventing damage to the impeller through backflow of the circulating pump. 2. In this invention, the condenser, cold trap, and adsorber are connected in sequence by pipelines, and the bottom of the adsorber is connected to the cold trap by pipelines to form a condensation circuit. This connection method is intended to make the material vapor condense and flow back as much as possible, so as to facilitate the observation of the working conditions of the condenser, reducing tee and cold trap, adsorb toxic and harmful gases escaping from the system, and keep the reaction system at normal pressure. 3. The connection method between the cold trap, ester tank and reaction vessel in this invention is designed to balance the pressure and ensure smooth dripping.

[0008] II. The present invention provides the following technical solutions: A clog-resistant reaction apparatus includes: a reaction vessel, a circulating pump, a cooler, a condenser, a cold trap, an ester tank, and an adsorber; The outlet of the ester tank is connected to the inlet of the reaction vessel via a pipeline; The reactor, circulating pump, cooler, and condenser are connected in series through pipelines to form a cooling circulation loop; The pipeline section between the circulating pump and the cooler is connected to the reactor via a pipeline to form a material mixing and circulation loop; the material mixing and circulation loop is connected to the cooling circulation loop via a return valve. The condenser, cold trap, and adsorber are connected in sequence by pipes, and the bottom of the adsorber is connected to the cold trap by pipes to form a condensation circuit; The exhaust port at the top of the ester tank is connected to the condensation circuit.

[0009] Preferably, the reaction vessel, circulating pump, cooler, and condenser are connected in series via pipelines to form a cooling circulation loop, including: The discharge port at the bottom of the reactor is connected to the inlet of the circulating pump in sequence via a three-way valve, a circulation valve, and a pre-pump valve; The outlet of the circulating pump is connected to the inlet at the bottom of the cooler in sequence through a pressure gauge, a downstream valve, and a flow regulating valve. The outlet at the top of the cooler is connected to the branch port of the reducing tee 2 via thermometer 2; The branch port of the reducing tee is equipped with a liner tube, which is inserted into the center of the reducing tee, and the end of the liner tube is connected to the nozzle. The lower straight end of the reducing tee is connected to the inner tube inlet at the top of the condenser, and the inner tube outlet at the bottom of the condenser is connected to the rising gas port of the reactor through the sight glass, forming a cooling circulation loop.

[0010] Preferably, the pipeline section between the circulating pump and the cooler is connected to the reactor via a pipeline to form a material mixing and circulation loop, including: The pipeline between the pump downstream valve and the flow regulating valve is connected in sequence to the mixing circulation inlet of the reactor through the bypass valve and the sight glass II, forming a material mixing circulation loop.

[0011] Preferably, the condenser, cold trap, and adsorber are connected in sequence via pipelines, and the bottom of the adsorber is connected to the cold trap via a pipeline to form a condensation circuit; including: The inner tube inlet at the bottom of the cold trap is connected to the condenser via the upper straight port of a reducing tee. The top of the cold trap is connected to the lower straight port of the reducing tee, and the branch port of the reducing tee is connected to the lower side of the adsorber; a sight glass is installed on the upper straight port of the reducing tee; and an vent valve is provided on the top of the adsorber. The inner tube of the cold trap has two branches at the top. One of the branches is connected to the outlet at the bottom of the adsorber in sequence through a reflux valve and a sight glass to form a condensation circuit.

[0012] Preferably, the connection of the exhaust port at the top of the ester tank to the condensation circuit includes: the exhaust port at the top of the ester tank being connected to another branch port of the cold trap.

[0013] Preferably, the outlet of the esterification tank is connected to the inlet of the reaction vessel via a pipeline, including: The discharge port at the bottom of the ester tank is connected to the ester inlet of the reactor in sequence via a drip valve and a sight glass.

[0014] Preferably, the reactor is an elliptical headed container type, with an internal stirrer and a thermometer, and an external jacket; The hot water inlet at the bottom of the jacket is connected to the hot water supply pipe through a hot water inlet valve. The hot water inlet is also connected to the hot water return pipe through a drain valve. The hot water outlet at the top of the jacket is connected to the hot water return pipe through a hot water outlet valve. The hot water outlet is also connected to a vent valve. The discharge port at the bottom of the reactor is connected to the crude product conveying pipe through the straight port of the tee and the discharge valve in sequence. The stirrer is installed at the center port at the top, the thermometer is installed at the temperature measuring port, and the aldehyde addition port is connected to the aldehyde supply pipe through the aldehyde addition valve.

[0015] Preferably, the circulating pump is a leak-free centrifugal pump; The cooler is a single-pass single-shell shell-and-tube heat exchanger. The cold water inlet at the lower side is connected to the circulating cold water supply pipe through cold water inlet valve two, and the cold water outlet at the upper side is connected to the circulating cold water return pipe through cold water outlet valve two. The condenser is a shell-and-tube heat exchanger. The cold water inlet at the lower side is connected to the circulating cold water supply pipe through a cold water inlet valve, and the cold water outlet at the upper side is connected to the circulating cold water return pipe through a cold water outlet valve. The cold trap is a shell-and-tube heat exchanger. The refrigerant inlet on the lower side is connected to the circulating refrigerant water supply pipe through a refrigerant inlet valve, and the refrigerant outlet on the upper side is connected to the circulating refrigerant return pipe through a refrigerant outlet valve. The ester tank is a vertical elliptical headed container with a top-mounted level gauge installed at the center of the top. The feed port is connected to the phosphite feed pipe through an ester feed valve. The adsorber is a vertical elliptical headed container filled with activated carbon adsorbent, and the vent at the top is connected to a vent pipe via a vent valve.

[0016] A method of operating an anti-clogging reaction device as described above includes the following steps: (1) Preparation: Put the reaction apparatus into a ready-to-start state, and pre-start the cooler, condenser and cold trap; add raw materials to the reaction vessel and ester tank respectively, and preheat the reaction vessel; (2) Reaction: At the reaction temperature, when the phosphite is dropped into the aldehyde, the reaction begins and strongly exothermics. At this time, the cooling circulation loop is started to remove the heat released by the reaction through circulating cold water. If the dropping rate of the phosphite and the flow rate of the cooling circulation loop are not coordinated, the reaction temperature will fluctuate to a certain extent. The reaction temperature can be restored to stability by adjusting the dropping rate of the phosphite and the flow rate of the cooling circulation loop. (3) Discharge: Stop heating the reactor, increase the flow rate of the cooling circulation loop to cool down, and after stopping the circulation cooling, open the return valve to let the material in the cooler flow into the reactor and release the crude product in the reactor; (4) Shutdown: Turn off the cooler, condenser and cold trap, as well as other equipment on the reaction apparatus.

[0017] Preferably, step (1) specifically includes: Close the discharge valve, water discharge valve, drip valve, reflux valve, return valve, flow regulating valve, and vent valve two. Open the cold water inlet valve two and cold water outlet valve two to introduce circulating cold water into the cooler. Open the cold water inlet valve one and cold water outlet valve one to introduce circulating cold water into the condenser. Open the refrigerant inlet valve and refrigerant outlet valve to introduce circulating refrigerant into the cold trap. Open the vent valve one. Open the aldehyde addition valve to add a certain amount of raw material aldehyde or aldehyde phosphonate solution to the reactor. After adding, close the aldehyde addition valve. Open the ester addition valve to add a certain amount of phosphite to the ester tank. After adding, close the ester addition valve. Start the stirrer. Open the circulation valve, pump inlet valve, pump outlet valve, and bypass valve. Start the circulation pump to circulate and mix the material through the mixing circulation loop. Open the hot water outlet valve and hot water inlet valve to introduce circulating hot water into the jacket to heat the material in the reactor.

[0018] Step (2) specifically includes: When thermometer 1 shows that the temperature inside the reactor has risen to 40℃, close the hot water inlet valve, open the dripping valve to start adding phosphite, open the flow control valve and observe the reflux of the liquid through sight glass 1. During the dripping process, control the reaction temperature within the specified range by adjusting the opening of the dripping valve and the flow control valve. Pay attention to the reaction temperature displayed on thermometer 1. When the reaction temperature rises sharply, reduce the opening of the dripping valve and increase the opening of the flow control valve. When the reaction temperature drops significantly, increase the opening of the dripping valve and decrease the opening of the flow control valve. When a liquid level appears in sight glass 3, open the reflux valve. After the dripping is complete, close the dripping valve and adjust the hot water inlet valve to control the reaction temperature within the specified range and maintain the reaction for a period of time. During the reaction, the working conditions inside the cold trap, reducing tee 2 and condenser can be observed periodically through the upper straight-mouth sight glass of reducing tee 1.

[0019] Step (3) specifically includes: When the heat preservation process ends, close the hot water inlet valve and the hot water outlet valve, open the vent valve and the drain valve to drain the hot water in the jacket, close the bypass valve, and fully open the flow regulating valve so that all the circulating material is cooled through the cooling circulation loop. When the temperature shown by thermometer one drops to 40°C, close the flow regulating valve, stop the circulation pump, stop the agitator, and open the return valve to let the material in the cooler flow back to the reactor. When the sight glass two shows no liquid flow, open the bypass valve and the flow regulating valve, and open the discharge valve to release the crude product. If production continues, repeat the above steps (1) to (3).

[0020] Step (4) specifically includes: After production is completed, close the second cold water inlet valve and the second cold water outlet valve to stop the flow of circulating cold water into the cooler, close the first cold water inlet valve and the first cold water outlet valve to stop the flow of circulating cold water into the condenser, close the refrigerant inlet valve and the refrigerant outlet valve to stop the flow of circulating refrigerant into the cold trap, release the cold water in the cooler shell side and the condenser sleeve and the refrigerant in the cold trap sleeve, regenerate or replace the adsorbent in the adsorber, close all open valves, and shut down the device for standby.

[0021] The phosphite is one or more of trimethyl phosphite, dimethyl phosphite, triethyl phosphite, or diethyl phosphite.

[0022] The aldehyde is formaldehyde, paraformaldehyde, acetaldehyde, metaldehyde, trichloroacetaldehyde, propionaldehyde, butyraldehyde, or glyoxal.

[0023] The reaction process of this invention generally does not require a solvent. However, if the raw material aldehyde is solid, it is necessary to dissolve the solid raw material aldehyde in advance using a phosphonate solvent or a portion of the crude product from the previous batch, so that the solid raw material aldehyde is added in solution form.

[0024] The anti-clogging reaction device and method provided in this invention have the following beneficial effects: (1) First, the circulating reaction mixture is cooled, and then it is directly contacted to condense the rising steam, so that the rising steam is condensed and refluxed as soon as it enters the rising gas port. The condenser is a shell-and-tube heat exchanger with a large diameter heat exchange tube. In addition, the scouring effect of the circulating material and the polymerization inhibitor brought in by the raw material aldehyde can effectively prevent the aldehyde from polymerizing to form solids that block the condenser tubes, ensuring normal production, reducing maintenance time, and improving equipment utilization. (2) By strengthening heat transfer through the cooling circulation loop, the heat of reaction is removed in the first time, and safety accidents caused by temperature rise will not occur. (3) Select equipment and accessories with excellent sealing performance, use cold traps to further condense and recover volatile components, and use activated carbon to adsorb and treat toxic and harmful exhaust gases to avoid environmental pollution. (4) No further polymerization inhibitors need to be added to the reaction mixture, thus avoiding product contamination and improving product quality. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a traditional reflux reaction apparatus; Figure 2 This is a schematic diagram of the structure of an anti-clogging reaction device according to the present invention; Wherein: 1-Reaction vessel; 2-Circulating pump; 3-Cooler; 4-Condenser; 5-Cold trap; 6-Ester tank; 7-Adsorber; 8-Tee; 9-Circulating valve; 10-Discharge valve; 11-Water drain valve; 12-Hot water inlet valve; 13-Agitator; 14-Thermometer 1; 15-Jacket; 16-Aldehyde addition valve; 17-Sight glass 4; 18-Drip valve; 19-Top-mounted level gauge; 20-Ester addition valve; 21-Reducing tee 1; 22-Reflux valve; 23-Vent valve 1; 24-Sight glass 3; 25 26-Refrigerant inlet valve; 27-Refrigerant outlet valve; 28-Cold water outlet valve 1; 29-Sprayer head; 20-Reducing tee 2; 31-Insert pipe; 32-Cold water inlet valve 1; 33-Sight glass 1; 34-Sight glass 2; 35-Thermometer 2; 36-Cold water outlet valve 2; 37-Return valve; 38-Bypass valve; 39-Flow regulating valve; 40-Vent valve 2; 41-Hot water outlet valve; 42-Post-pump valve; 43-Pressure gauge; 44-Pre-pump valve; Mixing circulation inlet 1a. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] I. Reference Figure 2 The present invention provides a reaction device and method for preventing blockage, in order to solve the above-mentioned technical problems. The technical solution is as follows:

[0028] A clog-proof reaction device, Includes: 1. Reactor; 2. Circulating pump; 3. Cooler; 4. Condenser; 5. Cold trap; 6. Ester tank; and 7. Adsorber. The outlet of the ester tank 6 is connected to the inlet of the ester reactor 1 via a pipeline; The reactor 1, circulating pump 2, cooler 3, and condenser 4 are connected in series through pipelines to form a cooling circulation loop; The pipeline section between the circulating pump 2 and the cooler 3 is connected to the reactor 1 through a pipeline to form a material mixing circulation loop; the material mixing circulation loop is connected to the cooling circulation loop through the return valve 37. Condenser 4, cold trap 5, and adsorber 7 are connected in sequence by pipes, and the bottom of adsorber 7 is connected to cold trap 5 by pipes to form a condensation circuit. The exhaust port at the top of the ester tank 6 is connected to the condensation circuit.

[0029] Specifically, reactor 1 is used for intermittent or semi-continuous strongly exothermic reflux reactions at room temperature to 100°C, initiated by heating with circulating hot water; the circulating pump provides power for external circulation mixing and cooling of the reactants; the cooler is used to cool the reactants, removing most of the heat released by the reaction, and any size heat exchanger can be selected as needed; the condenser mainly provides space for cold materials to directly contact hot material vapors, allowing the vapors to condense and flow back into the reactor, and removing some of the heat released by the reaction; the cold trap is used to further condense the tail gas generated by the reaction, allowing the liquefiable components to flow back; the ester tank is used to hold and meter phosphite, facilitating drip-based semi-continuous operation; the adsorption tank is used for gas-liquid separation to recover liquid materials entrained in the gas droplets and to adsorb toxic and harmful gases, meeting environmental protection requirements.

[0030] In this embodiment, the reactor 1, circulating pump 2, cooler 3, and condenser 4 are connected in series via pipelines to form a cooling circulation loop, including: The discharge port at the bottom of reactor 1 is connected to the inlet of circulating pump 2 in sequence via tee 8, circulation valve 9, and pump inlet valve 44; The outlet of the circulating pump 2 is connected to the inlet at the bottom of the cooler 3 in sequence through the pressure gauge 43, the pump post valve 42, and the flow regulating valve 39; The outlet at the top of the cooler 3 is connected to the branch port of the reducing tee 29 via thermometer 2 34; The branch port of reducing tee 29 is equipped with a insert tube 30, which is inserted into the center of reducing tee 29, and the end of the insert tube is connected to the nozzle 28; The lower straight end of the reducing tee 29 is connected to the inner tube inlet at the top of the condenser 4, and the inner tube outlet at the bottom of the condenser 4 is connected to the rising gas port of the reactor 1 through the sight glass 32, forming a cooling circulation loop.

[0031] In this embodiment, the pipeline section between the circulating pump 2 and the cooler 3 is connected to the reactor 1 via a pipeline to form a material mixing and circulation loop, including: The pipeline between the pump downstream valve 42 and the flow regulating valve 39 is connected to the mixing circulation inlet 1a of the reactor 1 in sequence through the bypass valve 38 and the sight glass 33, forming a material mixing circulation loop.

[0032] In this embodiment, the condenser 4, cold trap 5, and adsorber 7 are connected in sequence via pipelines, and the bottom of the adsorber 7 is connected to the cold trap 5 via a pipeline to form a condensation circuit; including: The inner tube inlet at the bottom of the cold trap 5 is connected to the condenser 4 through the upper straight port of the reducing tee 29; The top of the cold trap 5 is connected to the lower straight port of the reducing tee 21, and the branch port of the reducing tee 21 is connected to the lower side of the adsorber 7; a sight glass is installed on the upper straight port of the reducing tee 21; and an vent valve 23 is provided on the top of the adsorber 7. The upper part of the inner tube of the cold trap 5 is provided with two branches. One of the branches is connected to the discharge port at the bottom of the adsorber 7 through the reflux valve 22 and the sight glass 24 to form a condensation circuit.

[0033] In this embodiment, the connection of the exhaust port at the top of the ester tank 6 to the condensation circuit includes: the exhaust port at the top of the ester tank 6 is connected to another branch port of the cold trap 5.

[0034] In this embodiment, the outlet of the ester tank 6 is connected to the ester inlet of the reaction vessel 1 via a pipeline, including: The discharge port at the bottom of the ester tank 6 is connected to the ester inlet of the reactor 1 in sequence through the drip valve 18 and the sight glass 17.

[0035] In this embodiment, the reactor 1 is an elliptical headed container type, with a stirrer 13 and a thermometer 14 inside, and a jacket 15 outside; The hot water inlet at the lower part of the jacket 15 is connected to the hot water supply pipe through the hot water inlet valve 12. The hot water inlet is also connected to the hot water return pipe through the drain valve 11. The hot water outlet at the upper part of the jacket 15 is connected to the hot water return pipe through the hot water outlet valve 41. The hot water outlet is also connected to the vent valve 40. The discharge port at the bottom of the reactor 1 is connected to the crude product conveying pipe through the straight port of the tee 8 and the discharge valve 10 in sequence. The stirrer 13 is installed at the center port at the top, the thermometer 14 is installed at the temperature measuring port, and the aldehyde addition port is connected to the aldehyde supply pipe through the aldehyde addition valve 16.

[0036] The stirrer 13 in the reactor 1 mainly performs radial mixing, which, together with the axial mixing formed by the external circulation, can meet the requirement of uniform mixing of the reactants; the hot water heating through the jacket 15 can meet the requirement of initiating the reaction, and the hot water in the jacket can be released at the end of the reaction to accelerate the cooling process; the external circulation enhances heat exchange, which can meet the requirement of rapidly removing the heat of reaction in strongly exothermic reactions.

[0037] In this embodiment, the circulating pump 2 is a leak-free centrifugal pump; the leak-free centrifugal pump is a standard piece of equipment, easy to maintain, and meets the needs of conveying toxic and harmful materials.

[0038] The cooler 3 is a single-pass single-shell shell-and-tube heat exchanger. The cold water inlet at the lower side is connected to the circulating cold water supply pipe through the cold water inlet valve 2 36, and the cold water outlet at the upper side is connected to the circulating cold water return pipe through the cold water outlet valve 2 35. Cooler 3 uses a single-tube, single-shell heat exchanger, which is simple in structure, easy to maintain, and readily available. Under conditions of high heat load, a larger heat exchanger can be selected, or multiple shell-and-tube heat exchangers can be connected in series or in parallel to increase the heat exchange area.

[0039] The condenser 4 is a shell-and-tube heat exchanger. The cold water inlet at the lower side is connected to the circulating cold water supply pipe through the cold water inlet valve 31, and the cold water outlet at the upper side is connected to the circulating cold water return pipe through the cold water outlet valve 27. The cold trap 5 is a shell-and-tube heat exchanger. The refrigerant inlet on the lower side is connected to the circulating refrigerant water supply pipe through the refrigerant inlet valve 25, and the refrigerant outlet on the upper side is connected to the circulating refrigerant return pipe through the refrigerant outlet valve 26. Condenser 4 and cold trap 5 are selected as shell-and-tube heat exchangers, which have a simple structure and are easy to process and manufacture; the inner tube has a large diameter and serves as an ascending gas pipe and a return pipe, making it easy to observe the operating conditions.

[0040] The ester tank 6 is a vertical elliptical head container with a top-mounted level gauge 19 installed at the center of the top. The feed port is connected to the phosphite feed pipe through the ester feed valve 20. The ester tank 6 uses an elliptical head container, which is the most common standard container. It has a simple structure and is readily available. It is equipped with a top-mounted level gauge inside, making it less prone to breakage and ensuring a tight seal.

[0041] The adsorber 7 is a vertical elliptical head container filled with activated carbon adsorbent, and the vent at the top is connected to the vent pipe through the vent valve 23.

[0042] The adsorber 7 uses an elliptical head container, which is the most common standard container. It has a simple structure and is readily available. Inside, there is a grate plate, on which filter cloth is laid, and granular activated carbon is placed on the filter cloth. The exhaust gas enters under the grate plate, passes through the activated carbon adsorption layer, and flows out from the top. The space under the grate plate acts as a gas-liquid separator, where liquid droplets carried by the exhaust gas droplets drip and collect, and then flow back into the reactor through the cold trap and condenser.

[0043] The thermometer used in this invention is preferably a resistance thermometer.

[0044] II. Example: Taking the reaction of trimethyl phosphite and dimethyl phosphite with paraformaldehyde as an example;

[0045] The specific operating method is as follows: (1) Preparation: Close discharge valve 10, water discharge valve 11, drip valve 18, reflux valve 22, return valve 37, flow regulating valve 39 and vent valve 40. Open cold water inlet valve 36 and cold water outlet valve 35 to introduce circulating cold water into cooler 3. Open cold water inlet valve 31 and cold water outlet valve 27 to introduce circulating cold water into condenser 4. Open refrigerant inlet valve 25 and refrigerant outlet valve 26 to introduce circulating refrigerant into cold trap 5. Open vent valve 23. Open aldehyde addition valve 16 to add 600 kg of 96% pure paraformaldehyde solution to reactor 1. The solution in 700 kg of crude dimethyl hydroxymethylphosphonate is dissolved. After the addition is complete, the aldehyde addition valve 16 is closed, and the ester addition valve 20 is opened to add 166 kg of trimethyl phosphite and 1966 kg of dimethyl phosphite to the esterification tank 6. After the addition is complete, the ester addition valve 20 is closed, the stirrer 13 is started, and the circulation valve 9, the pump inlet valve 44, the pump outlet valve 42, and the bypass valve 38 are opened. The circulation pump 2 is started to circulate the material through the mixing circulation loop. The hot water outlet valve 41 and the hot water inlet valve 12 are opened to introduce circulating hot water into the jacket 15 to heat the material in the reactor 1. (2) Reaction: When the thermometer-14 shows that the temperature inside the reactor 1 has risen to 40℃, close the hot water inlet valve 12, open the dripping valve 18 to start adding phosphite, open the flow regulating valve 39 and observe the backflow of the liquid through the sight glass 32. During the dripping process, control the reaction temperature between 45 and 55℃ by adjusting the opening of the dripping valve 18 and the flow regulating valve 39. Pay attention to the reaction temperature displayed on the thermometer-14. When the reaction temperature rises sharply, reduce the opening of the dripping valve 18 and increase the flow regulating valve 39. When the reaction temperature drops significantly, increase the opening of the dripping valve 18 and decrease the opening of the flow regulating valve 39. Also, when a liquid surface appears in the sight glass 24, open the reflux valve 22. The dripping time is about 1.5 hours. After the dripping is completed, close the dripping valve 18 and adjust the hot water inlet valve 12 to control the reaction temperature at 70-80℃ and keep the reaction at that temperature for 2 hours. During the reaction, observe the working conditions of the cold trap 5, the reducing tee 29 and the condenser 4 periodically through the upper straight sight glass of the reducing tee 21. (3) Discharge: When the heat preservation process ends, close the hot water inlet valve 12 and the hot water outlet valve 41, open the venting valve 40 and the drain valve 11 to drain the hot water in the jacket 15, close the bypass valve 38, and fully open the flow regulating valve 39 so that all the circulating material is cooled through the cooling circulation loop. When the temperature shown by thermometer 14 drops to 40°C, close the flow regulating valve 39, stop the circulation pump 2, stop the agitator 13, and open the return valve 37 to let the material in the cooler 3 flow back to the reactor 1. When the sight glass 33 shows no liquid flow, open the bypass valve 38 and the flow regulating valve 39, and open the discharge valve 10 to discharge the crude product. If production continues, repeat the above steps 1 to 3. (4) Shutdown: After production is completed, close the cold water inlet valve 236 and the cold water outlet valve 235 to stop the flow of circulating cold water into the cooler 3, close the cold water inlet valve 131 and the cold water outlet valve 127 to stop the flow of circulating cold water into the condenser 4, close the refrigerant inlet valve 25 and the refrigerant outlet valve 26 to stop the flow of circulating refrigerant into the cold trap 5, release the cold water in the shell side of the cooler 3 and the sleeve of the condenser 4 as well as the refrigerant in the sleeve of the cold trap 5, regenerate or replace the adsorbent in the adsorber 7, close all open valves, and shut down the device for standby.

[0046] It should be noted that the specific models and parameters of the devices in the above embodiments are as follows: The circulating pump 2 is a 50CQ-40 type magnetically driven leak-free centrifugal pump, and the pressure gauge connected to the outlet of the circulating pump 2 has a range of 0 to 0.6 MPa.

[0047] Cooler 3 is a single-tube, single-shell shell-and-tube heat exchanger as specified in GB151-1999, with a heat exchange area of ​​40 m². 2 The tube side carries circulating materials, while the shell side carries circulating cold water. The cold water inlet at the lower side is connected to the circulating cold water supply pipe via cold water inlet valve 2 36, and the cold water outlet at the upper side is connected to the circulating cold water return pipe via cold water outlet valve 2 35.

[0048] Condenser 4 is a shell-and-tube heat exchanger with a nominal diameter of DN65 / 100 and a heat exchange area of ​​0.7m². 2 The cold water inlet at the lower side is connected to the circulating cold water supply pipe through the cold water inlet valve 31, and the cold water outlet at the upper side is connected to the circulating cold water return pipe through the cold water outlet valve 27.

[0049] Cold trap 5 is a shell-and-tube heat exchanger with a nominal diameter of DN65 / 100 and a heat exchange area of ​​0.7m². 2 The refrigerant inlet at the lower side is connected to the circulating refrigerant supply pipe via refrigerant inlet valve 25, and the refrigerant outlet at the upper side is connected to the circulating refrigerant return pipe via refrigerant outlet valve 26.

[0050] Ester tank 6 is a vertical elliptical head storage tank as specified in HG5-1579-85, with a nominal volume of 2.5m³. 3 A top-mounted level gauge 19 is installed at the center of the top, and the feed port is connected to the phosphite feed pipe through the ester feeding valve 20.

[0051] Adsorber 7 is a vertical elliptical head storage tank as specified in HG5-1578-85, with a nominal volume of 1m³. 3 It has both gas-liquid separation and adsorption functions. It is equipped with a grate plate, on which a filter cloth is laid. Granular activated carbon is placed on the filter cloth. The vent at the top is connected to the vent pipe through the vent valve 23.

[0052] The circulating cold water is clean water that is circulated at a temperature of 5–40°C.

[0053] The circulating refrigerant is a 50% ethylene glycol aqueous solution that is used in a cycle from -30 to -20°C.

[0054] The circulating hot water is clean water that is circulated at a temperature of 50–95°C.

[0055] The circulating cold water used in this invention can be circulating water at room temperature, but it is specified to be above 5°C to prevent freezing in winter.

[0056] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0057] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solutions and concepts of this invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A reaction apparatus for preventing clogging, characterized in that, include: Reactor, circulating pump, cooler, condenser, cold trap, ester tank and adsorber; The outlet of the ester tank is connected to the inlet of the reaction vessel via a pipeline; The reactor, circulating pump, cooler, and condenser are connected in series via pipelines to form a cooling circulation loop, including: The discharge port at the bottom of the reactor is connected to the inlet of the circulating pump in sequence via a three-way valve, a circulation valve, and a pre-pump valve; The outlet of the circulating pump is connected to the inlet at the bottom of the cooler in sequence through a pressure gauge, a downstream valve, and a flow regulating valve; The outlet at the top of the cooler is connected to the branch port of the reducing tee 2 via thermometer 2; The branch port of the reducing tee is equipped with a liner tube, which is inserted into the center of the reducing tee, and the end of the liner tube is connected to the nozzle. The lower straight end of the reducing tee is connected to the inner tube inlet at the top of the condenser, and the inner tube outlet at the bottom of the condenser is connected to the rising gas port of the reactor through the sight glass to form a cooling circulation loop. The pipeline section between the circulating pump and the cooler is connected to the reactor via a pipeline to form a material mixing and circulation loop; the material mixing and circulation loop is connected to the cooling circulation loop via a return valve. The condenser, cold trap, and adsorber are connected in sequence by pipes, and the bottom of the adsorber is connected to the cold trap by pipes to form a condensation circuit; The exhaust port at the top of the ester tank is connected to the condensation circuit.

2. The anti-clogging reaction device according to claim 1, characterized in that, The pipeline section between the circulating pump and the cooler is connected to the reactor via a pipeline, forming a material mixing and circulation loop, including: The pipeline between the pump downstream valve and the flow regulating valve is connected in sequence to the mixing circulation inlet of the reactor through the bypass valve and the sight glass II, forming a material mixing circulation loop.

3. The anti-clogging reaction device according to claim 2, characterized in that, The condenser, cold trap, and adsorber are connected in sequence via pipelines, and the bottom of the adsorber is connected to the cold trap via a pipeline to form a condensation circuit; including: The inner tube inlet at the bottom of the cold trap is connected to the condenser via the upper straight port of a reducing tee. The top of the cold trap is connected to the lower straight port of the reducing tee, and the branch port of the reducing tee is connected to the lower side of the adsorber; a sight glass is installed on the upper straight port of the reducing tee; and an vent valve is provided on the top of the adsorber. The inner tube of the cold trap has two branches at the top. One of the branches is connected to the outlet at the bottom of the adsorber in sequence through a reflux valve and a sight glass to form a condensation circuit.

4. The anti-clogging reaction device according to claim 3, characterized in that, The connection of the exhaust port at the top of the ester tank to the condensation circuit includes: the exhaust port at the top of the ester tank being connected to another branch of the cold trap.

5. The anti-clogging reaction device according to claim 4, characterized in that, The outlet of the ester tank is connected to the inlet of the reaction vessel via a pipeline, including: The discharge port at the bottom of the ester tank is connected to the ester inlet of the reactor in sequence via a drip valve and a sight glass.

6. The anti-clogging reaction device according to claim 5, characterized in that, The reactor is an elliptical headed container, with an internal stirrer and a thermometer, and an external jacket. The hot water inlet at the bottom of the jacket is connected to the hot water supply pipe through a hot water inlet valve. The hot water inlet is also connected to the hot water return pipe through a drain valve. The hot water outlet at the top of the jacket is connected to the hot water return pipe through a hot water outlet valve. The hot water outlet is also connected to a vent valve. The discharge port at the bottom of the reactor is connected to the crude product conveying pipe through the straight port of the tee and the discharge valve in sequence. The stirrer is installed at the center port at the top, the thermometer is installed at the temperature measuring port, and the aldehyde addition port is connected to the aldehyde supply pipe through the aldehyde addition valve.

7. The anti-clogging reaction device according to claim 5, characterized in that, The circulating pump is a leak-free centrifugal pump; The cooler is a single-pass single-shell shell-and-tube heat exchanger. The cold water inlet at the lower side is connected to the circulating cold water supply pipe through cold water inlet valve two, and the cold water outlet at the upper side is connected to the circulating cold water return pipe through cold water outlet valve two. The condenser is a shell-and-tube heat exchanger. The cold water inlet at the lower side is connected to the circulating cold water supply pipe through a cold water inlet valve, and the cold water outlet at the upper side is connected to the circulating cold water return pipe through a cold water outlet valve. The cold trap is a shell-and-tube heat exchanger. The refrigerant inlet on the lower side is connected to the circulating refrigerant water supply pipe through a refrigerant inlet valve, and the refrigerant outlet on the upper side is connected to the circulating refrigerant return pipe through a refrigerant outlet valve. The ester tank is a vertical elliptical headed container with a top-mounted level gauge installed at the center of the top. The feed port is connected to the phosphite feed pipe through an ester feed valve. The adsorber is a vertical elliptical headed container filled with activated carbon adsorbent, and the vent at the top is connected to a vent pipe via a vent valve.

8. A method of operating the anti-clogging reaction device as described in claim 7, characterized in that, Includes the following steps: (1) Preparation: Put the reaction apparatus into a ready-to-start state, and pre-start the cooler, condenser and cold trap; add raw materials to the reaction vessel and ester tank respectively, and preheat the reaction vessel; (2) Reaction: At the reaction temperature, when the phosphite is dropped into the aldehyde, the reaction begins and strongly exothermics. At this time, the cooling circulation loop is started to remove the heat released by the reaction through circulating cold water. If the dropping rate of the phosphite and the flow rate of the cooling circulation loop are not coordinated, the reaction temperature will fluctuate to a certain extent. The reaction temperature can be restored to stability by adjusting the dropping rate of the phosphite and the flow rate of the cooling circulation loop. (3) Discharge: Stop heating the reactor, increase the flow rate of the cooling circulation loop to cool down, and after stopping the circulation cooling, open the return valve to let the material in the cooler flow into the reactor and release the crude product in the reactor; (4) Shutdown: Turn off the cooler, condenser and cold trap, as well as other equipment on the reaction apparatus.

9. The method of operating the anti-clogging reaction device according to claim 8, characterized in that, Step (1) specifically includes: Close the discharge valve, water discharge valve, drip valve, reflux valve, return valve, flow regulating valve, and vent valve two. Open the cold water inlet valve two and cold water outlet valve two to introduce circulating cold water into the cooler. Open the cold water inlet valve one and cold water outlet valve one to introduce circulating cold water into the condenser. Open the refrigerant inlet valve and refrigerant outlet valve to introduce circulating refrigerant into the cold trap. Open the vent valve one. Open the aldehyde addition valve to add a certain amount of raw material aldehyde or aldehyde phosphonate solution to the reactor. After adding, close the aldehyde addition valve. Open the ester addition valve to add a certain amount of phosphite to the ester tank. After adding, close the ester addition valve. Start the stirrer. Open the circulation valve, pump inlet valve, pump outlet valve, and bypass valve. Start the circulation pump to circulate and mix the material through the mixing circulation loop. Open the hot water outlet valve and hot water inlet valve to introduce circulating hot water into the jacket to heat the material in the reactor. Step (2) specifically includes: When thermometer 1 shows that the temperature inside the reactor has risen to 40℃, close the hot water inlet valve, open the dripping valve to start adding phosphite, open the flow control valve and observe the reflux of the liquid through sight glass 1. During the dripping process, control the reaction temperature within the specified range by adjusting the opening of the dripping valve and the flow control valve. Pay attention to the reaction temperature displayed on thermometer 1. When the reaction temperature rises sharply, reduce the opening of the dripping valve and increase the opening of the flow control valve. When the reaction temperature drops significantly, increase the opening of the dripping valve and decrease the opening of the flow control valve. When a liquid level appears in sight glass 3, open the reflux valve. After the dripping is complete, close the dripping valve and adjust the hot water inlet valve to control the reaction temperature within the specified range and maintain the reaction for a period of time. During the reaction, the working conditions inside the cold trap, reducing tee 2 and condenser can be observed periodically through the upper straight-mouth sight glass of reducing tee 1. Step (3) specifically includes: When the heat preservation process ends, close the hot water inlet valve and the hot water outlet valve, open the vent valve and the drain valve to drain the hot water in the jacket, close the bypass valve, and fully open the flow regulating valve so that all the circulating material is cooled through the cooling circulation loop. When the temperature shown by thermometer one drops to 40°C, close the flow regulating valve, stop the circulation pump, stop the agitator, and open the return valve to let the material in the cooler flow back to the reactor. When the sight glass two shows no liquid flow, open the bypass valve and the flow regulating valve, and open the discharge valve to release the crude product. If production continues, repeat the above steps (1) to (3). Step (4) specifically includes: After production is completed, close the second cold water inlet valve and the second cold water outlet valve to stop the flow of circulating cold water into the cooler, close the first cold water inlet valve and the first cold water outlet valve to stop the flow of circulating cold water into the condenser, close the refrigerant inlet valve and the refrigerant outlet valve to stop the flow of circulating refrigerant into the cold trap, release the cold water in the cooler shell side and the condenser sleeve and the refrigerant in the cold trap sleeve, regenerate or replace the adsorbent in the adsorber, close all open valves, and shut down the device for standby.

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