CN219356178U - Production device for preparing methylal from dilute formaldehyde - Google Patents

Abstract

The utility model relates to a production device for preparing methylal by using dilute formaldehyde. Comprises a mixer for mixing raw materials, a preheater for heating the raw materials, a catalytic rectifying tower for raw material reaction, a reboiler for heating steam, a condenser for condensing methylal-containing gas and a reflux tank connected with the condenser; the discharge port of the mixer is connected with the feed port of the preheater; the discharge port of the preheater is connected with the feed port of the catalytic rectifying tower; the reboiler is connected with the catalytic rectifying tower; the catalytic rectifying tower is connected with the condenser; the reflux groove is connected with the catalytic rectifying tower; the catalytic rectifying tower is connected to the preheater. Solves the problems that the dilute formaldehyde generated in the methylal production process in the prior art cannot be recycled, the dilute formaldehyde needs to be independently recycled, the methylal production process is relatively complex, and the product generated by the reaction has corrosiveness to equipment.

Description

Production device for preparing methylal from dilute formaldehyde

Technical Field

The utility model relates to the field of chemical equipment, in particular to a production device for preparing methylal from dilute formaldehyde.

Background

At present, the dilute aldehyde concentration process mainly comprises a pressurized rectification concentration process and a vacuum flash evaporation concentration process.

Formaldehyde exists mainly in the form of hydrated formaldehyde in water, formaldehyde hydration reaction moves to the dehydration direction under pressure, and formaldehyde concentration in the solution increases. The larger the pressure is, the larger the difference between the dehydration reaction rate and the formaldehyde vaporization rate in the solution is, which is the principle of the pressurized rectification formaldehyde concentration process. 300kPa is commonly selected in industry as the operating pressure for formaldehyde pressure distillation. The pressurized rectifying and concentrating process has simple technology, short flow, easy realization of industrial production, simple and convenient personnel operation and lower energy consumption, and can realize the separation of the aldol and the concentration of the diluted aldehyde in one step. The defect is that along with the increase of pressure, formaldehyde is easy to oxidize at high temperature to produce formic acid, thereby not only causing formaldehyde loss, but also corroding rectification equipment to cause great hidden trouble affecting normal production.

The principle of the vacuum flash evaporation concentration process is that under a certain vacuum degree, the azeotropic phenomenon of the dilute formaldehyde and water disappears, and a part of water is separated when the heated dilute formaldehyde passes through a cyclone separator, so that the purpose of improving the formaldehyde concentration is achieved. In this process, temperature and vacuum are key factors in controlling the concentration of formaldehyde obtained. At present, the maximum concentration of formaldehyde obtained by vacuum concentration is 74%, and through industrial production practice, the industrial production device of 65-70% concentrated formaldehyde can realize long-period stable operation. The vacuum concentration reaction temperature is lower, the formic acid production amount is small, the equipment corrosion rate is low, but the process is relatively complex, and because impurities in the formaldehyde dilute solution cannot be separated in the vacuum concentration process, the impurities such as methanol and the like in the solution need to be separated and removed independently before the concentration and dehydration of the dilute formaldehyde.

Therefore, the traditional dilute formaldehyde concentration process can not recycle the dilute formaldehyde generated in the methylal production process, and the product for producing methylal can corrode reaction equipment.

Disclosure of Invention

According to the production device for preparing methylal from the diluted formaldehyde, the problem that the diluted formaldehyde produced in the methylal production process in the prior art scheme cannot be recycled, the diluted formaldehyde needs to be independently recycled, the methylal production process is relatively complex, and the product produced by the reaction is corrosive to equipment is solved.

The technical scheme adopted by the embodiment of the application is as follows:

a production device for preparing methylal by using dilute formaldehyde comprises a mixer for mixing raw materials, a preheater for heating the raw materials, a catalytic rectifying tower for raw material reaction, a reboiler for heating steam, a condenser for condensing methylal-containing gas and a reflux tank connected with the condenser; the discharge port of the mixer is connected with the feed port of the preheater; the discharge port of the preheater is connected with the feed port of the catalytic rectifying tower; the reboiler is connected with the catalytic rectifying tower; the catalytic rectifying tower is connected with the condenser; the reflux tank is connected with the catalytic rectifying tower; the catalytic rectifying tower is connected with the preheater.

The further technical scheme is as follows: the mixer comprises a shell, a feeding device for feeding materials, a mixing container for mixing the materials, a stirring device for stirring the materials and a discharging device for discharging; the feeding device is arranged on the shell; the stirring device is arranged on the shell; the discharging device is arranged in the shell; the mixing container is arranged in the discharging device; and a discharge hole of the discharge device is connected with a feed inlet of the preheater.

The further technical scheme is as follows: the feeding device comprises a feeding hole for feeding materials and a feeding pipe arranged on the shell; the feed inlet is arranged on the feed pipe; the feed pipe discharge port is positioned in the mixing container.

The further technical scheme is as follows: the stirring device comprises a stirring mechanism for stirring materials, a connecting rod connected to the stirring mechanism and a driving device for driving the stirring mechanism to rotate; the driving device is arranged on the shell; the driving end of the driving device is connected with the connecting rod; the stirring mechanism is located in the mixing vessel.

The further technical scheme is as follows: the stirring mechanism comprises a plurality of paddle assemblies arranged in a circumferential array and an annular hoop for fixing the paddle assemblies; the blade assembly is abutted against the connecting rod; the annular hoop is connected with the blade assembly; the blade assembly comprises an arc-shaped mounting plate, a blade for stirring materials and a fixed block connected to the arc-shaped mounting plate; the arc-shaped mounting plate is abutted against the connecting rod; the paddle is mounted on the fixed block.

The further technical scheme is as follows: the discharging device comprises a discharging container and a discharging pipe for outputting materials; the discharging container is arranged in the shell; the discharging pipe is connected to the discharging container; and the discharge hole of the discharge pipe is connected with the feed inlet of the preheater.

The further technical scheme is as follows: the production device for preparing methylal by using dilute formaldehyde also comprises a feed inlet opening device; the feed inlet opening device is arranged in the catalytic rectifying tower; the feed inlet opening device comprises a roll-over door used for resisting the feed inlet of the catalytic rectifying tower, a pin shaft used for rotating the roll-over door, a guide rod connected with the roll-over door, a sliding component used for driving the roll-over door to swing and a spring used for pulling the sliding component to slide; the roll-over door is arranged around the pin shaft; the pin shaft is arranged on the catalytic rectifying tower; the guide rod is connected to the sliding component; one end of the spring is connected with the sliding component, and the other end of the spring is connected with the catalytic rectifying tower.

The further technical scheme is as follows: the sliding component comprises a sliding block connected to the spring and a clamping block arranged on the sliding block; the sliding block slides on the catalytic rectifying tower; the clamping block is connected to the guide rod.

The further technical scheme is as follows: a reflux pump is arranged between the reflux tank and the catalytic rectifying tower; the reflux tank discharge port is connected with the reflux pump through a pipeline; the reflux pump is connected with the catalytic rectifying tower through a pipeline; the top of the catalytic rectifying tower is provided with a reflux liquid inlet; the reflux pump is connected with the reflux liquid inlet through a pipeline.

The further technical scheme is as follows: a circulating pump is arranged between the preheater and the catalytic rectifying tower; the preheater is connected with the circulating pump through a pipeline; the catalytic rectifying tower is connected with the circulating pump through a pipeline; a raw material outlet is arranged at the bottom of the catalytic rectifying tower; the circulating pump is connected with the raw material outlet through a pipeline.

One or more technical solutions provided in the embodiments of the present application at least have the following technical effects or advantages:

1. due to the adoption of the mixer, the mixer can fully mix the dilute formaldehyde solution and the methanol; the arrangement of the preheater can provide a preheating condition for the reaction between the dilute formaldehyde solution and the methanol; the reboiler is arranged, so that steam reaching the top of the catalytic rectifying tower is changed into high-concentration (85-92%) methylal gas, and then better enters the condenser; the arrangement of the reflux tank can enable part of reflux liquid in the reflux tank to be conveyed into the catalytic rectifying tower for recycling, and part of methylal is extracted as a finished product; the device can operate under normal pressure, the side reaction is less, the product does not corrode equipment, and the material of the rectifying equipment is common stainless steel, so that the device can operate safely and stably without potential safety hazard; therefore, the problems that dilute formaldehyde generated in the methylal production process in the prior art cannot be recycled, the methylal production process is relatively complex, and products generated by the reaction are corrosive to equipment are solved.

2. Due to the adoption of the shell, the mixing container and the stirring device, the dilute formaldehyde solution and the methanol can be fully mixed together. By means of the arrangement of the feed device, the dilute formaldehyde solution and the methanol can be led into the mixer. Through the arrangement of the discharging device, the fully mixed dilute formaldehyde solution and methanol can enter the preheater

3. Due to the adoption of the arrangement of the feed inlet and the feed pipe, the dilute formaldehyde solution and the methanol can be conveniently put in.

4. Due to the adoption of the stirring mechanism, the connecting rod and the driving device, the driving device works to drive the connecting rod to rotate, so that the stirring mechanism is driven to rotate, and formaldehyde solution and methanol in the mixing container can be fully mixed by the rotation of the stirring mechanism.

5. Due to the adoption of the arrangement of the blade assembly and the annular hoop, the blade assembly can be firmly fixed on the connecting rod, and meanwhile, the blade assembly can be conveniently detached and installed. Due to the adoption of the arc-shaped mounting plate, the paddles and the fixing blocks, when the paddles need to be disassembled and cleaned after long-time stirring of the formaldehyde solution and the methanol mixed solution, the paddles can be disassembled only by adjusting bolts and nuts on the fixing blocks.

6. Due to the arrangement of the discharging container and the discharging pipe, formaldehyde solution and methanol entering the preheater are materials which are fully mixed after being stirred.

7. Due to the adoption of the arrangement of the roll-over door, the pin shaft, the guide rod, the sliding component and the spring, the roll-over door can be automatically opened when formaldehyde and methanol mixed solution enters the catalytic rectifying tower, and when the formaldehyde and methanol mixed solution stops being conveyed to the catalytic rectifying tower, the sliding component is pulled to slide through the spring, so that the guide rod pulls the roll-over door to swing to be in a closed state.

8. Due to the arrangement of the sliding blocks and the clamping blocks, the sliding component can be pulled to slide on the catalytic rectifying tower more stably in the swing process of the roll-over door.

9. Due to the adoption of the arrangement of the reflux pump, methylal containing methanol can enter the reflux tank, one part of methylal is directly extracted as a finished product, and the other part of methylal reflux liquid containing methanol is conveyed into the catalytic rectifying tower through the reflux pump to continuously react. Because the reflux liquid inlet is arranged on the top of the catalytic rectifying tower, part of reflux liquid in the reflux tank enters the catalytic rectifying tower through the reflux liquid inlet to continue to react.

10. Due to the adoption of the arrangement of the circulating pump, formaldehyde which does not participate in the reaction in the catalytic rectifying tower can be condensed to form water containing a small amount of formaldehyde at the bottom of the tower, and then the water is conveyed into the preheater through the circulating pump for waste heat utilization, cooled and then is conveyed into the catalytic rectifying tower as a raw material for recycling. Because the raw material outlet is arranged at the bottom of the catalytic rectifying tower, water containing a small amount of formaldehyde in the bottom of the catalytic rectifying tower can be output through the raw material outlet.

Drawings

FIG. 1 is a schematic structural view of an apparatus for producing methylal from diluted formaldehyde according to an embodiment of the present utility model.

Fig. 2 is a schematic view of a portion of a structure for embodying a mixer according to an embodiment of the present utility model.

Fig. 3 is a schematic view of a portion of a structure for embodying the connection relationship between an annular hoop and a blade assembly according to an embodiment of the present utility model.

FIG. 4 is a schematic view of a portion of a structure for embodying a blade assembly in accordance with an embodiment of the present utility model.

Fig. 5 is a schematic view showing a part of the structure of a feed opening device according to an embodiment of the present utility model.

Fig. 6 is a schematic view of a portion of a sliding assembly according to an embodiment of the present utility model.

In the figure: 1. a mixer; 11. a housing; 12. a feeding device; 121. a feed inlet; 122. a feed pipe; 13. a mixing vessel; 14. a stirring device; 141. a stirring mechanism; 142. a connecting rod; 143. a driving device; 144. a blade assembly; 145. an annular hoop; 146. an arc-shaped mounting plate; 147. a paddle; 148. a fixed block; 15. a discharging device; 151. a discharge container; 152. a discharge pipe; 2. a preheater; 3. a catalytic rectifying column; 4. a reboiler; 5. a condenser; 6. a reflux groove; 7. a reflux pump; 8. a circulation pump; 9. a feed inlet opening device; 91. a roll-over door; 92. a pin shaft; 93. a guide rod; 94. a sliding assembly; 941. a slide block; 942. a clamping block; 95. and (3) a spring.

Detailed Description

According to the production device for preparing methylal from the diluted formaldehyde, the problem that the diluted formaldehyde produced in the methylal production process in the prior art scheme cannot be recycled, the diluted formaldehyde needs to be independently recycled, the methylal production process is relatively complex, and the product produced by the reaction is corrosive to equipment is solved.

The technical scheme in the embodiment of the application aims to solve the problems, and the overall thought is as follows:

in order to better understand the above technical solutions, the following detailed description will refer to the accompanying drawings and specific embodiments.

A production device for methylal by using dilute formaldehyde is shown in figure 1, and comprises a mixer 1 for mixing raw materials, a preheater 2 for heating the raw materials, a catalytic rectifying tower 3 for raw material reaction, a reboiler 4 for heating steam, a condenser 5 for condensing methylal-containing gas and a reflux tank 6 connected with the condenser 5. The discharge port of the mixer 1 is connected with the feed port of the preheater 2. The discharge port of the preheater 2 is connected with the feed port of the catalytic rectifying tower 3. The reboiler 4 is connected to the catalytic rectifying column 3. The catalytic rectifying column 3 is connected to a condenser 5. The reflux tank 6 is connected to the catalytic rectifying column 3. The catalytic rectifying column 3 is connected to the preheater 2.

The discharge port of the mixer 1 is connected with the feed port of the preheater 2 through a pipeline. The discharge port of the preheater 2 is connected with the feed port of the catalytic rectifying tower 3 through a pipeline. The reboiler 4 is connected with the catalytic rectifying tower 3 through a pipeline. The top of the catalytic rectifying tower 3 is provided with a gas phase outlet, and the gas phase outlet on the catalytic rectifying tower 3 is connected with a feed inlet of the condenser 5 through a pipeline. The discharge port of the condenser 5 is connected with the feed port of the reflux groove 6 through a pipeline. The reflux groove 6 is connected with the catalytic rectifying tower 3 through a pipeline. The catalytic rectifying tower 3 is connected with the preheater 2 through a pipeline. Firstly, dilute formaldehyde solution and methanol are fed according to a proportion, uniformly mixed in a mixer 1, preheated to 65-75 ℃ by a preheater 2, then fed into a catalytic rectifying tower 3, and the catalytic rectifying tower 3 is filled with a solid acid catalyst, and condensation reaction is carried out under the action of the solid acid catalyst to generate methylal. In the catalytic rectifying column 3, water (heavy component) contained in the rising vapor is transferred to a liquid phase, and methylal (light component) in the reflux liquid is transferred to a gas phase. Thus, the concentration of methylal in the rising vapor gradually increases, the vapor reaching the top of the catalytic rectifying column 3 becomes methylal gas with a high concentration (85 to 92%), and then the methylal gas is discharged from the gas phase outlet at the top of the catalytic rectifying column 3 to the condenser 5. The condensed methylal containing methanol enters a reflux groove 6, a part of reflux liquid in the reflux groove 6 is conveyed into the catalytic rectifying tower 3 for internal circulation, and a part of methylal is extracted as a finished product. The stripping section of the catalytic rectifying tower 3 gradually condenses water (heavy components) in rising steam so as to obtain water containing a small amount of formaldehyde at the bottom of the tower, and the water containing the small amount of formaldehyde is conveyed into the preheater 2 through a pipeline for waste heat utilization, and is used as a raw material for recycling after being cooled. The device operates under normal pressure, has less side reaction, does not corrode equipment, and adopts common stainless steel as material of rectifying equipment, so that the device operates safely and stably without potential safety hazard.

By the mixer 1 being provided, the mixer 1 enables the diluted formaldehyde solution and the methanol to be thoroughly mixed. The preheater 2 is arranged to provide preheating conditions for the reaction between the dilute formaldehyde solution and methanol. The reboiler 4 is provided to supply the vapor to the catalytic rectifying column 3, so that the vapor reaching the top of the catalytic rectifying column 3 becomes methylal gas with a high concentration (85 to 92%), and the methylal gas is more preferably introduced into the condenser 5. The arrangement of the reflux tank 6 can enable part of reflux liquid in the reflux tank 6 to be conveyed into the catalytic rectifying tower 3 for recycling, and part of methylal is extracted as a finished product. The device can operate under normal pressure, has less side reaction, does not corrode equipment, and adopts common stainless steel as material of rectifying equipment, so that the device can operate safely and stably without potential safety hazard. Therefore, the problems that dilute formaldehyde generated in the methylal production process in the prior art cannot be recycled, the methylal production process is relatively complex, and products generated by the reaction are corrosive to equipment are solved.

As shown in fig. 2, the mixer 1 comprises a housing 11, a feed device 12 for feeding in the material, a mixing vessel 13 for mixing the material, a stirring device 14 for stirring the material, and a discharge device 15 for discharging. The feeding device 12 is provided on the housing 11. The stirring device 14 is mounted on the housing 11. The discharge device 15 is mounted in the housing 11. The mixing vessel 13 is arranged in a discharge device 15. The discharge port of the discharge device 15 is connected with the feed port of the preheater 2.

Two groups of feeding devices 12 are fixedly connected to the top of the shell 11. The outlet end of the feeding device 12 is located in the mixing vessel 13. One set of feed devices 12 is used to deliver a dilute formaldehyde solution and the other set of feed devices 12 is used to deliver methanol. The stirring device 14 is fixedly mounted on the housing 11. The discharging device 15 is positioned in the shell 11, and meanwhile, the discharging device 15 is fixedly connected with the shell 11 through a fixing rod. The mixing container 13 is positioned in the discharging device 15, and the mixing container 13 and the discharging device 15 are fixedly connected together through a fixed rod. When the dilute formaldehyde solution and the methanol are put into the mixing container 13 through the feeding device 12, the mixed solution of the dilute formaldehyde solution and the methanol is stirred through the stirring device 14, so that the materials are fully mixed. By continuously adding the dilute formaldehyde solution and the methanol, the level of the mixed solution in the mixing container 13 is higher than the opening of the mixing container 13, so that the fully mixed dilute formaldehyde solution and methanol flow into the discharging device 15 through the mixing container 13, and then enter the preheater 2 through the discharging hole of the discharging device 15.

By the arrangement of the housing 11, the mixing vessel 13 and the stirring device 14, the diluted formaldehyde solution and the methanol can be sufficiently mixed together, and by the arrangement of the feeding device 12, the diluted formaldehyde solution and the methanol can be introduced into the mixer 1. By means of the arrangement of the discharge device 15, a well-mixed dilute formaldehyde solution and methanol can be brought into the preheater 2.

As shown in fig. 2, the feeding device 12 includes a feed port 121 for feeding a material and a feed pipe 122 provided on the housing 11. The feed port 121 is provided on the feed pipe 122. The outlet of the feed pipe 122 is located in the mixing vessel 13.

The vertical surface of the feed inlet 121 is preferably in a conical structure, so that the dilute formaldehyde solution and the methanol can be conveniently fed. The feed port 121 is fixedly connected to the top of the feed tube 122. The feed tube 122 is fixedly connected to the housing 11.

Through the arrangement of the feed inlet 121 and the feed pipe 122, the feeding of the dilute formaldehyde solution and the methanol can be facilitated.

As shown in fig. 2, the stirring device 14 includes a stirring mechanism 141 for stirring a material, a connecting rod 142 connected to the stirring mechanism 141, and a driving device 143 for driving the stirring mechanism 141 to rotate. The driving device 143 is mounted on the housing 11. The driving end of the driving device 143 is connected to the connecting rod 142. The stirring mechanism 141 is located in the mixing vessel 13.

Two groups of stirring mechanisms 141 are fixedly connected to the bottom end of the connecting rod 142. Each set of stirring mechanisms 141 is located in the mixing vessel 13 for stirring the formaldehyde solution and methanol. The driving device 143 is fixedly installed at the top of the housing 11. The driving means 143 is preferably a motor. The driving device 143 is drivingly connected to the connecting rod 142. The driving end of the driving device 143 rotates to drive the connecting rod 142 to rotate, so as to drive the stirring mechanism 141 to rotate.

Through the setting of rabbling mechanism 141, connecting rod 142 and drive arrangement 143, work through drive arrangement 143 drives connecting rod 142 and rotates, and then drives the rotation of rabbling mechanism 141, and the rotation of rabbling mechanism 141 can make formaldehyde solution and the abundant mixing of methyl alcohol in the mixing vessel 13.

As shown in fig. 3, the stirring mechanism 141 includes a plurality of paddle assemblies 144 arranged in a circumferential array and an annular hoop 145 for fixing the paddle assemblies 144. The paddle assembly 144 rests on the connecting rod 142. Annular staple 145 is attached to paddle assembly 144. The paddle assembly 144 includes an arcuate mounting plate 146, paddles 147 for agitating the material, and a fixed block 148 attached to the arcuate mounting plate 146. The arcuate mounting plate 146 abuts the connecting rod 142. The paddle 147 is mounted on a fixed block 148.

The stirring mechanism 141 includes three sets of paddle assemblies 144 arranged in a circumferential array. Each set of paddle assemblies 144 rests on the connecting rod 142 and is fixedly connected to the connecting rod 142 by two sets of annular hoops 145. The annular hoop 145 is provided with an adapted bolt and nut. The annular hoop 145 is locked by bolts and nuts, so that each group of blade assemblies 144 is firmly fixed on the connecting rod 142, and the blade assemblies 144 are convenient to detach and replace when damaged. The fixed block 148 is fixedly attached to the arcuate mounting plate 146. The fixed block 148 is fixedly connected with the blade 147 through bolts and nuts. Therefore, after the paddle 147 stirs the formaldehyde solution and the methanol for a long time, the paddle 147 can be detached by rotating the nut to perform cleaning and replacement.

Through the setting of paddle subassembly 144 and annular staple bolt 145, can make paddle subassembly 144 firmly fix on connecting rod 142, conveniently dismantle the installation simultaneously to paddle subassembly 144. Through the setting of arc mounting panel 146, paddle 147 and fixed block 148, when paddle 147 need dismantle the washing after long-time stirring formaldehyde solution and methyl alcohol mixed solution, only need can realize dismantling paddle 147 through adjusting bolt and nut on the fixed block 148.

As shown in fig. 2, the tapping device 15 comprises a tapping vessel 151 and a tapping pipe 152 for tapping the material. The discharge container 151 is installed in the housing 11. Discharge tube 152 is connected to discharge vessel 151. The discharge hole of the discharge pipe 152 is connected with the feed hole of the preheater 2.

The discharging container 151 is fixedly connected with the shell 11 through a fixing rod. Discharge tube 152 is fixedly connected to housing 11. The feed inlet of the discharge pipe 152 is fixedly connected to the discharge container 151, and the discharge outlet of the discharge pipe 152 is fixedly connected to the feed inlet of the preheater 2. Thus, when the well-mixed formaldehyde solution and methanol enter discharge vessel 151, it is passed through discharge pipe 152 to preheater 2.

Through the arrangement of the discharge container 151 and the discharge pipe 152, the formaldehyde solution and the methanol which enter the preheater 2 can be materials which are fully mixed after being stirred.

As shown in fig. 5, the apparatus for producing methylal from diluted formaldehyde of the present embodiment further comprises a feed opening device 9. A feed opening device 9 is provided in the catalytic rectifying column 3. The feed opening device 9 includes a roll-over door 91 for withstanding the feed opening of the catalytic rectification column 3, a pin shaft 92 for rotating the roll-over door 91, a guide rod 93 connected to the roll-over door 91, a slide assembly 94 for driving the roll-over door 91 to swing, and a spring 95 for pulling the slide assembly 94 to slide. The roll-over door 91 is disposed around the pin 92. The pin 92 is provided on the catalytic rectifying column 3. The guide rod 93 is connected to a slide assembly 94. Spring 95 is connected at one end to slide assembly 94 and at the other end to catalytic rectifying column 3.

The feed opening device 9 is fixedly connected in the catalytic rectifying tower 3. The roll-over door 91 is disposed around the pin 92 while the roll-over door 91 is rotatable around the pin 92. The pin 92 is fixedly connected in the catalytic rectifying tower 3. The guide bar 93 is hinged at one end to the roll-over door 91 and at the other end to the slide assembly 94. One end of the spring 95 is fixedly connected to the sliding assembly 94, and the other end is fixedly connected to the catalytic rectifying tower 3. The sliding assembly 94 is slidably connected to the catalytic rectifying column 3. When the preheated formaldehyde and methanol mixed solution is fed to the feed port of the catalytic rectifying column 3, the roll-over door 91 is swung into an open state by an impact force caused by the mixed solution. The roll-over door 91 swings to drive the guide rod 93 to pull the sliding component 94 to slide on the catalytic rectifying tower 3, and at the moment, the spring 95 is in a stretched state. When the mixed solution of formaldehyde and methanol stops being conveyed, the sliding assembly 94 slides reversely due to the elastic force of the spring 95, and then the guide rod 93 pulls the roll-over door 91 to swing, so that the roll-over door 91 abuts against the feed inlet of the catalytic rectifying tower 3.

Through roll-over door 91, round pin axle 92, guide bar 93, sliding component 94 and spring 95's setting can make formaldehyde and methyl alcohol mixed solution enter into catalytic distillation tower 3 roll-over door 91 automatic open, when formaldehyde and methyl alcohol mixed solution stop carrying in catalytic distillation tower 3, through spring 95 pulling sliding component 94 slip, and then make guide bar 93 pulling roll-over door 91 swing for the closed condition.

As shown in fig. 5 and 6, the slider assembly 94 includes a slider 941 coupled to a spring 95 and a latch 942 provided on the slider 941. The slider 941 slides on the catalytic rectifying column 3. The latch 942 is coupled to the guide rod 93.

The slider 941 is fixedly attached to the spring 95. The catalytic rectifying tower 3 is provided with a chute adapted to the slide 941, the slide 941 slides on the chute, and the arrangement of the chute is used for limiting the slide 941. The latch 942 is slidably coupled to the slider 941, and the latch 942 is fixedly coupled to the guide bar 93. When the roll-over door 91 swings to enable the guide rod 93 to pull the sliding component 94 to slide, the clamping block 942 can slide downwards at this time, the sliding block 941 slides on the sliding groove of the catalytic rectifying tower 3, and then the sliding component 94 can be more stable in the sliding process.

Through the arrangement of the slide block 941 and the clamping block 942, the sliding component 94 can be pulled to slide on the catalytic rectifying tower 3 more stably in the swinging process of the roll-over door 91.

As shown in fig. 1, a reflux pump 7 is provided between the reflux tank 6 and the catalytic rectifying column 3. The discharge port of the reflux tank 6 is connected with the reflux pump 7 through a pipeline. The reflux pump 7 is connected with the catalytic rectifying tower 3 through a pipeline. The top of the catalytic rectifying tower 3 is provided with a reflux inlet. The reflux pump 7 is connected with the reflux inlet through a pipeline.

One end of the reflux pump 7 is fixedly connected with the discharge port of the reflux groove 6 through a pipeline. The other end of the reflux pump 7 is fixedly connected with the catalytic rectifying tower 3 through a pipeline. When the condensed methylal containing methanol enters the reflux tank 6, one part of methylal is directly extracted as a finished product, and the other part of methylal is conveyed to the catalytic rectifying tower 3 through the reflux pump 7 for continuous reaction, so that the reaction of the dilute formaldehyde solution in the catalytic rectifying tower 3 and the methanol is more sufficient. The top of the catalytic rectifying tower 3 is provided with a reflux liquid inlet. The reflux pump 7 is fixedly connected with the reflux liquid inlet through a pipeline. The reflux liquid is conveyed to the reflux liquid inlet of the catalytic rectifying tower 3 through the reflux pump 7, then enters the catalytic rectifying tower 3 through the reflux liquid inlet, and continuously reacts in the catalytic rectifying tower 3.

By arranging the reflux pump 7, methylal containing methanol can enter the reflux tank 6, one part of methylal is directly extracted as a finished product, and the other part of methylal reflux liquid containing methanol is conveyed into the catalytic rectifying tower 3 through the reflux pump 7 to continue to react. By arranging the reflux liquid inlet on the top of the catalytic rectifying tower 3, part of reflux liquid in the reflux tank 6 enters the catalytic rectifying tower 3 through the reflux liquid inlet to continue to react.

As shown in fig. 1, a circulation pump 8 is provided between the preheater 2 and the catalytic rectifying column 3. The preheater 2 is connected with the circulating pump 8 through a pipeline. The catalytic rectifying tower 3 is connected with the circulating pump 8 through a pipeline. A raw material outlet is arranged at the tower bottom of the catalytic rectifying tower 3. The circulating pump 8 is connected with the raw material outlet through a pipeline.

One end of the circulating pump 8 is fixedly connected with the tower kettle of the catalytic rectifying tower 3 through a pipeline. The other end of the circulating pump 8 is fixedly connected with the preheater 2 through a pipeline. The stripping section in the catalytic rectifying tower 3 gradually condenses water (heavy components) in rising steam, water containing a small amount of formaldehyde is obtained at the bottom of the tower, the water is conveyed into the preheater 2 through the circulating pump 8 for waste heat utilization, and the water is conveyed into the catalytic rectifying tower 3 as a raw material for recycling after being cooled. A raw material outlet is arranged at the tower bottom of the catalytic rectifying tower 3. The circulating pump 8 is fixedly connected with the raw material outlet through a pipeline. The water containing a small amount of formaldehyde in the catalytic rectifying tower 3 is output from a raw material outlet at the tower bottom of the catalytic rectifying tower 3.

Through the arrangement of the circulating pump 8, formaldehyde which does not participate in the reaction in the catalytic rectifying tower 3 can be condensed to form water containing a small amount of formaldehyde at the bottom of the tower, and then the water is conveyed into the preheater 2 through the circulating pump 8 for waste heat utilization, cooled and then conveyed into the catalytic rectifying tower 3 as a raw material for recycling. The raw material outlet is formed in the tower bottom of the catalytic rectifying tower 3, so that water containing a small amount of formaldehyde in the tower bottom of the catalytic rectifying tower 3 can be output through the raw material outlet.

While preferred embodiments of the present utility model have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the utility model.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present utility model without departing from the spirit or scope of the utility model. Thus, it is intended that the present utility model also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (10)

1. The production device for preparing methylal by using dilute formaldehyde is characterized by comprising a mixer (1) for mixing raw materials, a preheater (2) for heating the raw materials, a catalytic rectifying tower (3) for raw material reaction, a reboiler (4) for heating steam, a condenser (5) for condensing methylal-containing gas and a reflux tank (6) connected with the condenser (5); the discharge port of the mixer (1) is connected with the feed port of the preheater (2); the discharge port of the preheater (2) is connected with the feed port of the catalytic rectifying tower (3); the reboiler (4) is connected with the catalytic rectifying tower (3); the catalytic rectifying tower (3) is connected with the condenser (5); the reflux groove (6) is connected with the catalytic rectifying tower (3); the catalytic rectifying tower (3) is connected with the preheater (2).

2. A plant for the production of methylal from diluted formaldehyde according to claim 1, characterized in that said mixer (1) comprises a housing (11), a feeding device (12) for feeding the material, a mixing container (13) for mixing the material, a stirring device (14) for stirring the material and a discharge device (15) for discharging; the feeding device (12) is arranged on the shell (11); the stirring device (14) is arranged on the shell (11); the discharging device (15) is arranged in the shell (11); the mixing container (13) is arranged in the discharging device (15); the discharge port of the discharge device (15) is connected with the feed port of the preheater (2).

3. A plant for the production of methylal with diluted formaldehyde according to claim 2, characterized in that said feeding means (12) comprise a feed opening (121) for the feeding of the material and a feed pipe (122) provided on said housing (11); the feed inlet (121) is arranged on the feed pipe (122); the discharge hole of the feed pipe (122) is positioned in the mixing container (13).

4. A plant for producing methylal with diluted formaldehyde according to claim 3, characterized in that said stirring means (14) comprise stirring means (141) for stirring the material, a connecting rod (142) connected to said stirring means (141) and driving means (143) for driving said stirring means (141) in rotation; the driving device (143) is mounted on the housing (11); the driving end of the driving device (143) is connected to the connecting rod (142); the stirring mechanism (141) is located in the mixing container (13).

5. The apparatus for producing methylal from diluted formaldehyde according to claim 4, wherein said stirring means (141) comprises a plurality of blade assemblies (144) arranged in a circumferential array and an annular anchor (145) for fixing said blade assemblies (144); -said paddle assembly (144) resting on said connecting rod (142); the annular hoop (145) is connected to the blade assembly (144); the blade assembly (144) comprises an arc-shaped mounting plate (146), blades (147) for stirring materials and a fixed block (148) connected to the arc-shaped mounting plate (146); the arc-shaped mounting plate (146) is abutted against the connecting rod (142); the paddle (147) is mounted on the fixed block (148).

6. A plant for the production of methylal from diluted formaldehyde according to claim 2, characterized in that said tapping means (15) comprise a tapping container (151) and a tapping pipe (152) for tapping the material; the discharging container (151) is arranged in the shell (11); the discharging pipe (152) is connected to the discharging container (151); and a discharge hole of the discharge pipe (152) is connected with a feed inlet of the preheater (2).

7. The apparatus for producing methylal from dilute formaldehyde according to claim 1, further comprising a feed opening means (9); the feed inlet opening device (9) is arranged in the catalytic rectifying tower (3); the feed opening device (9) comprises a roll-over door (91) for resisting the feed opening of the catalytic rectifying tower (3), a pin shaft (92) for rotating the roll-over door (91), a guide rod (93) connected with the roll-over door (91), a sliding component (94) for driving the roll-over door (91) to swing and a spring (95) for pulling the sliding component (94) to slide; the roll-over door (91) is arranged around the pin shaft (92); the pin shaft (92) is arranged on the catalytic rectifying tower (3); the guide rod (93) is connected to the sliding assembly (94); one end of the spring (95) is connected with the sliding component (94), and the other end of the spring is connected with the catalytic rectifying tower (3).

8. The apparatus for producing methylal with diluted formaldehyde according to claim 7, wherein said sliding assembly (94) comprises a slider (941) connected to said spring (95) and a block (942) provided on said slider (941); the sliding block (941) slides on the catalytic rectifying tower (3); the clamping block (942) is connected to the guide rod (93).

9. The apparatus for producing methylal from diluted formaldehyde according to claim 1, wherein a reflux pump (7) is provided between the reflux tank (6) and the catalytic rectifying column (3); the discharge port of the reflux tank (6) is connected with the reflux pump (7) through a pipeline; the reflux pump (7) is connected with the catalytic rectifying tower (3) through a pipeline; a reflux liquid inlet is formed in the top of the catalytic rectifying tower (3); the reflux pump (7) is connected with the reflux liquid inlet through a pipeline.

10. A plant for the production of methylal from lean formaldehyde according to claim 2, characterized in that a circulation pump (8) is arranged between the preheater (2) and the catalytic rectifying column (3); the preheater (2) is connected with the circulating pump (8) through a pipeline; the catalytic rectifying tower (3) is connected with the circulating pump (8) through a pipeline; a raw material outlet is arranged at the tower kettle of the catalytic rectifying tower (3); the circulating pump (8) is connected with the raw material outlet through a pipeline.