CN115709039A - Device for preparing dimethylamino ethyl acrylate - Google Patents

Abstract

The invention relates to the technical field of a dimethylamino ethyl acrylate preparation device, in particular to a device for preparing dimethylamino ethyl acrylate. A system for preparing dimethylaminoethanol acrylate sequentially comprises a reaction kettle and a distillation tower from bottom to top, wherein the distillation tower sequentially comprises a stripping unit and a rectifying unit from bottom to top; the reaction kettle is used for containing reaction liquid, and is provided with a heating device which is used for heating the reaction kettle so as to enable reactants in the reaction liquid to react and the reaction liquid to be evaporated; and a first mixed gas formed by evaporating reaction liquid in the reaction kettle sequentially passes through the stripping unit and the rectifying unit, a substance with a high boiling point in the first mixed gas is liquefied and flows back to the reaction kettle, and methanol with a low boiling point in the gas is discharged from the rectifying unit. The embodiment of the invention provides a device for preparing dimethylaminoethyl acrylate, which can carry out polymerization reaction and distillation purification.

Description

Device for preparing dimethylamino ethyl acrylate

Technical Field

The invention relates to the technical field of a dimethylamino ethyl acrylate preparation device, in particular to a device for preparing dimethylamino ethyl acrylate.

Background

Under the condition of using dibutyl oxide as a main catalyst, dimethyl aminoethanol and methyl acrylate as raw materials are subjected to esterification reaction, which is a main process method for producing the dimethyl aminoethyl acrylate at present, but a byproduct methanol is generated in the reaction process, and the methanol needs to be continuously removed by a distillation method in the reaction process.

In the related technology, when the dimethylaminoethyl acrylate is prepared, a plurality of devices such as a reaction kettle, a distillation kettle, a rectifying tower and the like are needed, so that the cost is high and the occupied space is large.

Therefore, in view of the above disadvantages, an apparatus for preparing dimethylaminoethyl acrylate is urgently needed.

Disclosure of Invention

The embodiment of the invention provides a device for preparing dimethylaminoethyl acrylate, which can carry out polymerization reaction and distillation purification.

The embodiment of the invention provides a system for preparing dimethylaminoethanol acrylate, which sequentially comprises a reaction kettle and a distillation tower from bottom to top, wherein the distillation tower sequentially comprises a stripping unit and a rectifying unit from bottom to top;

the reaction kettle is used for containing reaction liquid and is provided with a heating device, and the heating device is used for heating the reaction kettle so as to enable reactants in the reaction liquid to react and enable the reaction liquid to evaporate;

and a first mixed gas formed by evaporating reaction liquid in the reaction kettle sequentially passes through the stripping unit and the rectifying unit, a substance with a high boiling point in the first mixed gas is liquefied and flows back to the reaction kettle, and methanol with a low boiling point in the gas is discharged from the rectifying unit.

In one possible design, the reaction kettle is connected with the top of the stripping unit through a pipeline, the reaction liquid in the reaction kettle is pumped to the top of the stripping unit through a first diaphragm pump, and the reaction liquid at the top of the stripping unit passes through the stripping unit and flows into the reaction kettle;

and the reaction liquid flows back to the reaction kettle from the top of the stripping unit, the reaction liquid is evaporated to form second mixed gas, and the second mixed gas and the first mixed gas upwards sequentially pass through the stripping unit and the rectifying unit to obtain methanol gas and discharge the methanol gas out of the rectifying unit.

In a possible design, the inside stirring wheel that is provided with of reation kettle, the reation kettle bottom through the pipeline with stirring wheel inlet is connected, first diaphragm pump will reaction liquid pump income in the reation kettle the stirring wheel, reaction liquid among the stirring wheel flows back extremely reation kettle, the stirring wheel is provided with the spiral guide plate, the spiral guide plate includes a plurality of page pieces, and the reaction liquid process the in-process of spiral guide plate is strikeed the page piece is with the drive the page piece is rotatory, the page piece is rotatory with the stirring reaction liquid among the reation kettle.

In one possible design, the reaction kettle is connected with a liquid storage tank through the first diaphragm pump, the liquid storage tank is connected with a second diaphragm pump, the second diaphragm pump is connected with a first spray head at the top of the stripping unit through a main pipe, the second diaphragm pump is connected with a polymerization inhibitor tank through a branch pipe, the main pipe is provided with a Venturi pipe, the polymerization inhibitor tank is connected with the Venturi pipe, and polymerization inhibitor is filled in the polymerization inhibitor tank;

utilize first diaphragm pump will reaction liquid pump among the reation kettle is gone into the liquid storage pot utilizes the second diaphragm pump will reaction liquid pump in the liquid storage pot is gone into first shower head, first shower head sprays reaction liquid extremely the unit of stripping utilizes the second diaphragm pump will reaction liquid pump in the liquid storage pot is gone into polymerization inhibitor jar is in order to dilute the polymerization inhibitor in the polymerization inhibitor jar, and the reaction liquid passes through form the low pressure during venturi, so that dilution polymerization inhibitor in the polymerization inhibitor dilution pipe is inhaled venturi, dilution polymerization inhibitor in the venturi and reaction liquid mix output extremely first shower head.

In a possible design, the trunk line has the auxiliary line in parallel, the trunk line with the auxiliary line all is provided with the valve, opens the valve of trunk line and closes the valve of auxiliary line, dilute polymerization inhibitor in the polymerization inhibitor jar with reaction liquid in the liquid storage pot passes through the trunk line is exported extremely first shower head, opens the valve of auxiliary line and closes the valve of trunk line, reaction liquid in the liquid storage pot passes through the trunk line is exported extremely first shower head.

In one possible design, the reactor bottom is provided with a low-oxygen air distribution disc, which is connected to an air compressor outside the reactor through an air feed pipe, for providing low-oxygen air to prevent polymerization.

In a possible design, the hypoxic air distribution plate is provided with a plurality of upward air outlet holes, the air outlet holes are provided with hole covers through three guide rails, the hole covers rise along the guide rails during air supply, and the hole covers descend along the guide rails during air supply stopping, so as to cover the air holes.

In a possible design, heating device cladding is in the reation kettle outside, heating device includes protective layer, sandwich layer and ceramic layer along the thickness direction in proper order, the protective layer is used for reducing the heat loss, the sandwich layer is used for providing the heat, the ceramic layer with reation kettle pastes mutually, be used for to reation kettle heat conduction.

In one possible design, a second spray header is arranged at the upper part of the rectification unit and used for spraying insulating liquid to the rectification unit, and the insulating liquid comprises liquefied methanol discharged out of the distillation tower.

In one possible design, the ratio of the diameters of the reaction vessel, the stripping unit and the rectification unit is 1: 0.68-0.85: 0.55 to 0.65.

Compared with the prior art, the invention at least has the following beneficial effects:

in this embodiment, the reaction vessel is used for containing the reaction solution, and the heating device can provide the reaction solution with the temperature required for the reaction, and in addition, the heating device is also used for providing the thermal power for the evaporation of the reaction solution. The distillation tower comprising a stripping unit and a rectifying unit is arranged at the upper part of the reaction kettle, a first mixed gas formed by evaporating reaction liquid in the reaction kettle sequentially passes through the stripping unit and the rectifying unit, a substance with a high boiling point in the first mixed gas is liquefied and flows back to the reaction kettle, and methanol with a low boiling point in the first mixed gas is discharged from the rectifying unit. Through combining reation kettle and distillation column, arrange reation kettle in the distillation column bottom, can realize the excellent effect of simultaneous reaction and distillation, saved time and plane occupation of land space. In addition, the heating device can provide heat for the reaction, and can also promote the evaporation of the reaction liquid to discharge the methanol out of the reaction kettle, thereby saving energy.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a system for preparing dimethylethyl acrylate according to an embodiment of the present invention;

FIG. 2 is a schematic view of a low oxygen air distribution plate according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a hole cover structure according to an embodiment of the present invention;

FIG. 4 is a schematic view of a partial structure of a heating apparatus according to an embodiment of the present invention;

FIG. 5 is a schematic view of a partial structure of a stirring cycle according to a comparative example of the present invention;

FIG. 6 is a schematic view of a partial structure of a cycle of another stripping unit according to a comparative example of the present invention.

In the figure:

1-an air compressor;

2-an air supply pipe;

3-a hypoxic air distribution plate;

4-a protective layer;

5-a core layer;

6-a ceramic interlayer;

7-manhole;

8-a liquid outlet pipe;

9-a first diaphragm pump;

10-a liquid outlet;

11-a liquid level meter;

12-a stirring wheel;

13-a feed inlet;

14-a first thermocouple interface;

15-packing layer of stripping section;

16-a first liquid phase distributor;

17-a liquid inlet pipe;

18-a first liquid return pipe;

19-a liquid storage tank;

20-stripping circulation pipe;

21-a second diaphragm pump;

22-a second liquid return pipe;

23-a polymerization inhibitor tank;

24-a main pipeline;

25-secondary piping;

26-a first showerhead;

27-a rectifying section packing layer;

28-a second liquid phase distributor;

29-a second showerhead;

30-a tower top demister;

31-a second thermocouple interface;

32-a gas phase discharge port at the top of the tower;

33-safety accessory interface.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the scope of the present invention.

In the description of the embodiments of the present invention, unless explicitly specified or limited otherwise, the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more unless specified or indicated otherwise; the terms "connected," "fixed," and the like are to be construed broadly and may, for example, be fixedly connected, detachably connected, integrally connected, or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the description of the present invention, it should be understood that the terms "upper" and "lower" as used in the description of the embodiments of the present invention are used in the angle shown in the drawings, and should not be construed as limiting the embodiments of the present invention. In addition, in this context, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on "or" under "the other element or be indirectly on" or "under" the other element through intervening elements.

As shown in fig. 1, an embodiment of the present invention provides a system for preparing dimethylaminoethanol acrylate, which comprises a reaction kettle and a distillation tower from bottom to top in sequence, wherein the distillation tower comprises a stripping unit and a rectifying unit from bottom to top in sequence;

the reaction kettle is used for containing reaction liquid and is provided with a heating device which is used for heating the reaction kettle so as to react reactants in the reaction liquid and evaporate the reaction liquid;

the first mixed gas formed by evaporating the reaction liquid in the reaction kettle sequentially passes through the stripping unit and the rectifying unit, the substances with high boiling points in the first mixed gas are liquefied and flow back to the reaction kettle, and the methanol with low boiling points in the gas is discharged from the rectifying unit.

In this embodiment, the reaction vessel is used for containing the reaction solution, and the heating device can provide the reaction solution with the temperature required for the reaction, and in addition, the heating device is also used for providing the thermal power for the evaporation of the reaction solution. A distillation tower comprising a stripping unit and a rectifying unit is arranged at the upper part of the reaction kettle, a first mixed gas formed by evaporating reaction liquid in the reaction kettle sequentially passes through the stripping unit and the rectifying unit, a substance with a high boiling point in the first mixed gas is liquefied and flows back to the reaction kettle, and methanol with a low boiling point in the first mixed gas is discharged from the rectifying unit. Through combining reation kettle and distillation column, arrange reation kettle in the distillation column bottom, can realize the excellent effect of simultaneous reaction and distillation, saved time and plane occupation of land space. In addition, the heating device can provide heat for the reaction, and can also promote the evaporation of the reaction liquid to discharge the methanol out of the reaction kettle, thereby saving energy.

In the present embodiment, the first liquid phase distributor 16 and the second liquid phase distributor 28 may be provided at the stripping unit and the rectifying unit, respectively.

In this embodiment, reation kettle is provided with manhole 7, feed inlet 13, level gauge 11 and first thermocouple interface 14, and feed inlet 13 is used for throwing the material, and level gauge 11 is used for acquireing the liquid level height in the reation kettle, and first thermocouple interface 14 is used for installing warm pressure detection device.

In this embodiment, the stripping unit and the rectifying unit are filled with a packing for liquefying a high boiling point substance in the mixed gas to discharge methanol in a gas phase from the distillation column. Calculating the number of required theoretical plates according to an ideal system gas-liquid phase equilibrium equation, a coordinate calculation formula of the intersection point of a rectifying section operating line and a stripping section operating line, an operating line equation and a q-line equation, and then calculating and determining the type, height and porosity of the filler according to the relationship between the number of the plates and the height and bulk density of the filler, wherein the porosity of the filler layer is reduced from bottom to top in sequence, so that the airflow is uniformly distributed; the filler material is based on the material which is not easy to block, preferably pall ring and intalox saddle ring fillers.

As shown in fig. 1 and fig. 6, in some embodiments of the present invention, the reaction kettle is connected to the top of the stripping unit through a pipeline, the reaction liquid in the reaction kettle is pumped to the top of the stripping unit through the first diaphragm pump 9, and the reaction liquid at the top of the stripping unit flows into the reaction kettle through the stripping unit;

and in the process that the reaction liquid flows back to the reaction kettle from the top of the stripping unit, the reaction liquid is evaporated to form a second mixed gas, and the second mixed gas and the first mixed gas sequentially pass through the stripping unit and the rectifying unit upwards to obtain methanol gas which is discharged out of the rectifying unit.

In this embodiment, the pipe connection is passed through with stripping unit top to reation kettle, the pipeline is provided with first diaphragm pump 9, utilize the reactant liquid pump in first diaphragm pump 9 with reation kettle to stripping unit top, the reaction liquid at stripping unit top passes in the stripping unit inflow reation kettle, form the circulation of reaction liquid, the reaction liquid is in the cyclic process, constantly there is reaction liquid from stripping unit top inflow reation kettle, the reaction liquid passes the in-process of stripping unit and constantly evaporates formation second mist, second mist upwards passes stripping unit and rectification unit in proper order, the material that the boiling point is high is making progress the in-process liquefaction and flowing into reation kettle downwards, the low methyl alcohol of boiling point upwards passes rectification unit discharge distillation column all the time. Continuous circulation has increased the efficiency of distillation, and the in-process that the reaction liquid flows downwards can promote the liquefaction of low boiling point material in the mist, and simultaneously, high boiling point material in the reaction liquid vaporizes more easily and gets into and follow the mist upward movement, finally makes the methyl alcohol in the reation kettle discharge rapidly, and then has improved the quality of dimethylamino ethyl acrylate in the reation kettle.

As shown in fig. 5, in some embodiments of the present invention, a stirring wheel 12 is disposed inside the reaction kettle, the bottom of the reaction kettle is connected to a liquid inlet of the stirring wheel 12 through a pipeline, the first diaphragm pump 9 pumps the reaction liquid in the reaction kettle into the stirring wheel 12, the reaction liquid in the stirring wheel 12 flows back to the reaction kettle, the stirring wheel 12 is provided with a spiral flow guide plate, the spiral flow guide plate includes a plurality of leaves, the leaves are impacted by the reaction liquid during passing through the spiral flow guide plate to drive the leaves to rotate, and the leaves rotate to stir the reaction liquid in the reaction kettle.

In this embodiment, through the output of first diaphragm pump 9 with the reactant liquid pump in the reation kettle to stirring wheel 12, be provided with the spiral guide plate including a plurality of vanes in the stirring wheel 12, the reactant liquid constantly strikes the vane from the in-process of stirring wheel 12 output and makes the vane rotatory, and the reactant liquid among the rotatory vane constantly stirs reation kettle, and then accelerates the speed of evaporation and reaction.

As shown in fig. 1 and fig. 6, in some embodiments of the present invention, the reaction kettle is connected with a liquid storage tank 19 through a first diaphragm pump 9, the liquid storage tank 19 is connected with a second diaphragm pump 21, the second diaphragm pump 21 is connected with a first spray header 26 at the top of the stripping unit through a main pipe 24, the second diaphragm pump 21 is connected with a polymerization inhibitor tank 23 through a branch pipe, the main pipe 24 is provided with a venturi pipe, the polymerization inhibitor tank 23 is connected with the venturi pipe, and a polymerization inhibitor is contained in the polymerization inhibitor tank 23;

utilize first diaphragm pump 9 to go into liquid storage pot 19 with the reaction liquid pump in the reation kettle, utilize second diaphragm pump 21 to go into first shower head 26 with the reaction liquid pump of liquid storage pot 19, first shower head 26 sprays reaction liquid to the stripping unit, utilize second diaphragm pump 21 to go into polymerization inhibitor jar 23 with the polymerization inhibitor in the dilution polymerization inhibitor jar 23 with the reaction liquid pump of liquid storage pot 19, form the low pressure when reaction liquid passes through venturi, so that the dilution polymerization inhibitor in the polymerization inhibitor diluent pipe is inhaled venturi, dilution polymerization inhibitor and the reaction liquid mixing output in the venturi are to first shower head 26.

In this embodiment, the first diaphragm pump 9 is used to pump the reaction solution in the reaction kettle into the liquid storage tank 19, so that the liquid storage tank 19 is filled with the reaction solution, the second diaphragm pump 21 is used to pump the reaction solution in the liquid storage tank 19 into the first spray header 26 through the main pipe 24, and the reaction solution is sprayed to the stripping unit through the first spray header 26 to accelerate the evaporation and separation of the reaction solution. In order to avoid the polymerization reaction of the reaction liquid during the spraying process, a polymerization inhibitor needs to be added before the reaction liquid enters the first spraying head 26, but the excessive polymerization inhibitor can affect the quality of the product. Therefore, a polymerization inhibitor tank 23 containing a polymerization inhibitor is arranged, the polymerization inhibitor tank 23 is connected with a quantitative adding system, the quantitative adding system is used for adding the polymerization inhibitor into the polymerization inhibitor tank 23, meanwhile, the polymerization inhibitor tank 23 is connected with the liquid storage tank 19, and reaction liquid in the liquid storage tank 19 is pumped into the polymerization inhibitor tank 23 through a second diaphragm pump 21 to obtain a diluted polymerization inhibitor; polymerization inhibitor jar 23 is still connected through the venturi in lateral conduit and the trunk line 24, and when reacting liquid passes through venturi in trunk line 24, venturi department forms the low pressure, and under the low pressure effect, the dilution polymerization inhibitor in polymerization inhibitor jar 23 is inhaled venturi through the lateral conduit, and the reaction liquid in dilution polymerization inhibitor and the trunk line 24 gets into first shower head 26 jointly and then sprays to the stripping unit. After the diluted polymerization inhibitor is sprayed to the stripping unit along with the reaction liquid, one part of the diluted polymerization inhibitor flows downwards along with the liquid phase to prevent liquid phase substances from generating polymerization reaction, and the other part of the diluted polymerization inhibitor is vaporized to flow upwards along with the gas phase to prevent gas phase substances from polymerizing reaction.

As shown in fig. 6, in some embodiments of the present invention, the main pipe 24 is connected in parallel with the sub-pipe 25, both the main pipe 24 and the sub-pipe 25 are provided with valves, the valve of the main pipe 24 is opened and the valve of the sub-pipe 25 is closed, the diluted retarder in the retarder tank 23 and the reaction liquid in the storage tank 19 are outputted to the first shower head 26 through the main pipe 24, the valve of the sub-pipe 25 is opened and the valve of the main pipe 24 is closed, and the reaction liquid in the storage tank 19 is outputted to the first shower head 26 through the main pipe 24.

In this embodiment, a small amount of polymerization inhibitor is added into the reaction kettle to prevent the reactants in the reaction solution from generating polymerization reaction when the temperature is raised, and after the temperature of the reactants in the reaction kettle reaches a preset temperature, the sub-pipeline 25 is opened to allow the first spray header 26 to spray the reaction solution. As the polymerization inhibitor in the reaction kettle is continuously consumed, the auxiliary pipeline 25 is closed, and the main pipeline 24 is opened so that the first spray header 26 outputs the diluted polymerization inhibitor and the reaction liquid. So set up, keep a small amount of polymerization inhibitor in making the reaction system all the time, and then prevent to take place polymerization in the reaction system, simultaneously, also can not influence product quality because of polymerization inhibitor is excessive.

In this embodiment, the storage tank 19 is provided with a first liquid return pipe 18, the polymerization inhibitor tank 23 is provided with a second liquid return pipe 22, the first liquid return pipe 18 and the second liquid return pipe 22 are used for discharging the reaction liquid during shutdown or maintenance, and the first liquid return pipe 18 and the second liquid return pipe 22 are closed during normal operation.

It should be noted that the reaction kettle is connected with the first diaphragm pump 9 through the liquid outlet pipe 8, and the first diaphragm pump 9 is connected with the liquid storage tank 19 through the liquid inlet pipe 17. The first diaphragm pump 9 is connected with a liquid discharge port 10, when liquid in the reaction kettle needs to be emptied, the liquid discharge port 10 is opened, and the liquid in the reaction kettle is discharged through the liquid discharge port 10 by using the first diaphragm pump 9.

As shown in fig. 1, 2 and 3, in some embodiments of the present invention, a low-oxygen air distribution plate 3 is disposed at the bottom of the reaction vessel, the low-oxygen air distribution plate 3 is connected to an air compressor 1 outside the reaction vessel through an air supply pipe 2, and the low-oxygen air distribution plate 3 is used to supply low-oxygen air to prevent the polymerization reaction.

In this embodiment, set up low oxygen air distribution dish 3 in the reation kettle bottom, low oxygen air distribution dish 3 can upwards export low oxygen air, and the low oxygen air both can hinder polymerization, also can increase aerodynamic force.

It is understood that the hypoxic air distribution plate 3 can also be connected to a compressor containing nitrogen gas, which is output to the reaction tank.

In some embodiments of the present invention, the low-oxygen air distribution plate 3 is provided with a plurality of upward air outlets, the air outlets pass through the hole covers provided on the three guide rails, the hole covers are raised along the guide rails when air is supplied, and the hole covers are lowered along the guide rails when air supply is stopped, so as to cover the air holes.

In this embodiment, the low oxygen air distribution plate 3 is provided with a plurality of upward air outlets, the air outlets are provided with hole covers through guide rails, when the air outlets output gas, the gas drives the hole covers to slide upward along the guide rails, the gas is output from between the hole openings and the hole covers, and when the gas supply is stopped, the hole covers slide downward along the guide rails to the closed hole covers, so that the reaction liquid is prevented from entering the air outlets along the hole openings.

It will be appreciated that a rubber ring may be provided on the bottom of the aperture cover to further increase the seal when the aperture cover is closed. A spring may be provided on the slide to increase the speed at which the orifice cover closes, the spring force requiring less pneumatic force than the outlet.

In this embodiment, the air outlet holes of the low-oxygen air distribution plate 3 may be filled with a porous material, such as air stones. The air outlet adopts a detachable design, so that the maintenance is convenient.

As shown in fig. 4, in some embodiments of the present invention, the heating device is covered outside the reaction kettle, the heating device sequentially includes a protective layer 4, a core layer 5 and a ceramic layer 6 along a thickness direction, the protective layer 4 is used for reducing heat loss, the core layer 5 is used for providing heat, and the ceramic layer 6 is attached to the reaction kettle and used for conducting heat to the reaction kettle.

In this embodiment, the protection layer 4 is made of bakelite or ABS engineering plastic, preferably a temperature-resistant high-hardness bakelite material, and is lined with a high-temperature reflective coating to locally change the direction of heat radiation and reduce heat loss. The core layer 5 comprises an electromagnetic heating copper wire, a heating ceramic body and a filling material, and the filling material plays a role in insulation and heat preservation. The bottom of the reaction kettle is heated by an electromagnetic heating copper wire, and the side wall of the reaction kettle is heated by a heating ceramic body. Ceramic layer 6 adopts components of a whole that can function independently equipment or integrated into one piece mode processing, and heat conduction silica gel coats with reation kettle contact surface, guarantees to closely combine with the reation kettle outer wall, guarantees the heat conduction effect, prevents that the reation kettle outer wall from corroding.

It should be noted that, the outer wall of the ceramic layer 6 contacts with the heating copper wire or the heating ceramic body of the core layer 5, and a groove matching with the heating copper wire or the heating ceramic body needs to be reserved in the ceramic layer 6.

In some embodiments of the invention, a second spray header 29 is provided above the rectification unit, the second spray header 29 being used to spray a holding liquid to the rectification unit, the holding liquid comprising liquefied methanol exiting the distillation column.

In this embodiment, the methanol gas exits the distillation column and is condensed into a liquid, and a portion of the liquid may be sprayed to the rectification unit through the second spray header 29 to maintain the temperature at the top of the rectification unit.

It should be noted that whether the condensate of the byproduct is sprayed by the second spray header 29 can be determined according to the value of the tower top temperature and pressure monitoring interface.

In some embodiments of the invention, the ratio of the diameters of the reaction vessel, stripping unit, and rectification unit is 1: 0.68-0.85: 0.55-0.65.

In this example, the diameters of the reaction vessel, stripping unit and rectification unit are preferably in the ratio of 1:0.73:0.56, reation kettle and distillation column adopt the reducing design, are favorable to increaseing stripping section evaporation area, improve the vapor phase evaporation volume, and the route of corresponding extension vapor phase distillation section and the liquefied area of gaseous phase are favorable to high boiling substance liquefaction backward flow simultaneously, improve product yield when improving distillation separation purity, reduce reaction time. The tower body which is thinned from bottom to top can obviously improve the aerodynamic force of a gas phase.

The distillation column may be provided with a second thermocouple connection 31 and a safety fitting connection 33. The system provided by the invention is provided with temperature, pressure, pump current and pump voltage online detection devices, is connected with a PLC distributed control system of a master control room, sends control signals to automatic flow meters, electromagnetic control valves and other devices according to transmission temperature and pressure data, controls the circulating flow of reaction liquid, the gas supply amount, the mixed addition amount of polymerization inhibitor and the tower top temperature, maintains the normal operation of the whole system reaction, and ensures that the indexes of distilled products are qualified.

Example (b):

a methanol reaction distillation separation section:

starting an air compressor 1, and supplying air to the reaction kettle through an air supply pipe 2 and a low-oxygen air distribution disc 3; opening a feeding hole 13, adding dimethylamino ethanol and methyl acrylate into the reaction kettle, wherein the methyl acrylate is excessive, transmitting a liquid level signal to a control center by a liquid level meter 11 after reaching a heating starting liquid level, starting a heating device for heating, and continuing to feed materials until reaching a specified reaction liquid level; when the temperature is heated to 80 ℃, a butyl tin oxide catalyst is added through a catalyst feeding system through a feeding port, a first diaphragm pump 9 is started, reaction liquid enters a liquid outlet pipe 8 and then enters a stirring wheel 12, the reaction liquid pushes the stirring wheel 12 to enhance the stirring of the reaction liquid, a heating ceramic body in a core layer 5 is started to heat, the temperature rises to the reaction temperature of 100 ℃ within a set time, an electromagnetic heating part is taken as a main part, the heating of the heating ceramic body is taken as an auxiliary part, the reaction temperature is kept, the electromagnetic heating is controlled by an online temperature monitoring device connected with a first thermocouple interface 14, the advance can be set through a control system, and the temperature of the reaction liquid is kept stable. Keeping the reaction for 1.5 to 2 hours, and then slowly adding an entrainer, wherein n-hexane is preferred as the entrainer.

When the entrainer is added, the passage of the liquid inlet pipe 17 is opened, the reaction liquid is injected into the liquid storage tank 19, a signal is sent out after the preset liquid level is reached, the second diaphragm pump 21 is started, the auxiliary pipeline 25 is opened and the main pipeline 24 is closed in the first half reaction time, and the reaction liquid is sprayed down through the stripping circulation pipe 20, the second diaphragm pump 21, the auxiliary pipeline 25 and the first spray header 26; and during the second half reaction time, closing the auxiliary pipeline 25, opening the main pipeline 24, adding a polymerization inhibitor into the polymerization inhibitor tank 23 through a quantitative adding system, enabling diluent to enter the polymerization inhibitor tank 23 through a branch pipeline of the second diaphragm pump 21, mixing the diluted polymerization inhibitor into the first spray header 26 through the main pipeline 24, mixing the diluted polymerization inhibitor with the reaction liquid, spraying the mixture to the first liquid phase distributor 16, and returning the mixture to the reaction kettle through the stripping section packing layer 15.

After the liquid phase circulation is normal, the gas phase rises to a gas phase discharge port 32 at the top of the tower through a stripping section packing layer 15, a rectifying section packing layer 27, a second liquid phase distributor 28, a second spray header 29 and a tower top demister 30, the temperature at the top of the tower rises to 45-55 ℃, preferably 50.5 ℃, the gas phase discharge port 32 at the top of the tower is opened, the gas phase enters a condenser, a reflux pump is started after a condensate tank reaches the reflux pump start liquid level, the temperature at the top of the tower is kept, a mixed solution of the entrainer and the methanol is separated out, the entrainer is cut out after the mixed solution is kept stand and layered for recycling, the methanol water solution is further distilled and purified, and the finished product tank is fed after the takeaway standard is reached.

The reaction process can last for 6 to 8 hours, positive pressure in the tower needs to be kept in the reaction process, condensation circulation is added, and after sampling is qualified, the reaction distillation and methanol separation section is finished and the product enters a product rectification section.

A product rectifying section:

the product rectification period lasts from 5 to 8 hours, preferably 6.5 hours. Keeping the secondary conduit 25 solenoid closed. A part of the circulating liquid of the reaction kettle enters a liquid storage tank 19 through a liquid inlet pipe 17, and under the action of a second diaphragm pump 21, the circulating liquid is sprayed downwards through a stripping circulating pipe 20 and a main pipe 24 through a first spray header 26. The temperature at the top of the column is controlled to be 60-80 ℃, preferably 65 ℃.

During product rectification, compared with a reaction distillation section, a vacuum pump at the top of the tower needs to be started to maintain negative pressure in the tower, and the product is subjected to reduced pressure distillation, so that the product purity is more conveniently improved.

The implementation effect is as follows: compared with the common distillation tower, the consumption of the polymerization inhibitor is reduced by more than 22%, the product yield is improved by more than 5%, and the loss rate is reduced by more than 0.8%.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A system for preparing acrylic acid dimethylamino ethanol is characterized by comprising a reaction kettle and a distillation tower from bottom to top in sequence, wherein the distillation tower comprises a stripping unit and a rectifying unit from bottom to top in sequence;

the reaction kettle is used for containing reaction liquid, and is provided with a heating device which is used for heating the reaction kettle so as to enable reactants in the reaction liquid to react and the reaction liquid to be evaporated;

and a first mixed gas formed by evaporating reaction liquid in the reaction kettle sequentially passes through the stripping unit and the rectifying unit, a substance with a high boiling point in the first mixed gas is liquefied and flows back to the reaction kettle, and methanol with a low boiling point in the gas is discharged from the rectifying unit.

2. The system according to claim 1, wherein the reaction kettle is connected with the top of the stripping unit through a pipeline, the reaction liquid in the reaction kettle is pumped to the top of the stripping unit through a first diaphragm pump (9), and the reaction liquid at the top of the stripping unit flows into the reaction kettle through the stripping unit;

and the reaction liquid flows back to the reaction kettle from the top of the stripping unit, the reaction liquid is evaporated to form second mixed gas, and the second mixed gas and the first mixed gas upwards sequentially pass through the stripping unit and the rectifying unit to obtain methanol gas and discharge the methanol gas out of the rectifying unit.

3. The system according to claim 2, characterized in that a stirring wheel (12) is arranged inside the reaction kettle, the bottom of the reaction kettle is connected with a liquid inlet of the stirring wheel (12) through a pipeline, the first diaphragm pump (9) pumps the reaction liquid in the reaction kettle into the stirring wheel (12), the reaction liquid in the stirring wheel (12) flows back to the reaction kettle, the stirring wheel (12) is provided with a spiral guide plate, the spiral guide plate comprises a plurality of blades, the blades are impacted by the reaction liquid in the process of passing through the spiral guide plate to drive the blades to rotate, and the blades rotate to stir the reaction liquid in the reaction kettle.

4. The system according to claim 2, wherein the reaction kettle is connected with a liquid storage tank (19) through the first diaphragm pump (9), the liquid storage tank (19) is connected with a second diaphragm pump (21), the second diaphragm pump (21) is connected with a first spray header (26) at the top of the stripping unit through a main pipe (24), the second diaphragm pump (21) is connected with a polymerization inhibitor tank (23) through a branch pipe, the main pipe (24) is provided with a Venturi pipe, the polymerization inhibitor tank (23) is connected with the Venturi pipe, and polymerization inhibitor is contained in the polymerization inhibitor tank (23);

utilize first diaphragm pump (9) will reaction solution pump among the reation kettle is gone into liquid storage pot (19), utilizes second diaphragm pump (21) will reaction solution pump in liquid storage pot (19) is gone into first shower head (26), first shower head (26) spray reaction solution extremely stripping unit utilizes second diaphragm pump (21) will reaction solution pump in liquid storage pot (19) is gone into polymerization inhibitor jar (23) in order to dilute polymerization inhibitor jar (23), the reaction solution passes through form the low pressure during venturi, so that dilution polymerization inhibitor in the polymerization inhibitor dilution pipe is inhaled venturi, dilution polymerization inhibitor in the venturi extremely with reaction solution mixing output first shower head (26).

5. The system according to claim 4, wherein the main pipe (24) is connected in parallel with a secondary pipe (25), the main pipe (24) and the secondary pipe (25) are provided with valves, the valve of the main pipe (24) is opened and the valve of the secondary pipe (25) is closed, the diluted polymerization inhibitor in the polymerization inhibitor tank (23) and the reaction liquid in the liquid storage tank (19) are output to the first spray header (26) through the main pipe (24), the valve of the secondary pipe (25) is opened and the valve of the main pipe (24) is closed, and the reaction liquid in the liquid storage tank (19) is output to the first spray header (26) through the main pipe (24).

6. The system according to claim 1, characterized in that the reactor bottom is provided with a low oxygen air distribution disk (3), the low oxygen air distribution disk (3) is connected with an air compressor (1) outside the reactor through an air feed pipe (2), and the low oxygen air distribution disk (3) is used for providing low oxygen air to prevent polymerization reaction.

7. The system according to claim 6, wherein the low oxygen distribution plate (3) is provided with a plurality of upward air outlets, and the air outlets are provided with hole covers through three guide rails, wherein the hole covers are raised along the guide rails when air is supplied, and are lowered along the guide rails when air supply is stopped to cover the air outlets.

8. The system according to claim 1, wherein the heating device is coated outside the reaction kettle, the heating device sequentially comprises a protective layer (4), a core layer (5) and a ceramic layer (6) along the thickness direction, the protective layer (4) is used for reducing heat loss, the core layer (5) is used for providing heat, and the ceramic layer (6) is attached to the reaction kettle and used for conducting heat to the reaction kettle.

9. The system according to claim 1, characterized in that a second spray header (29) is arranged at the upper part of the rectification unit, the second spray header (29) is used for spraying a heat preservation liquid to the rectification unit, and the heat preservation liquid comprises liquefied methanol discharged from the distillation tower.

10. The system of claim 1, wherein the ratio of diameters of the reaction vessel, stripping unit, and rectification unit is from 1: 0.68-0.85: 0.55 to 0.65.

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