CN210796292U - Continuous rectification and purification device for m-phthalonitrile - Google Patents
Continuous rectification and purification device for m-phthalonitrile Download PDFInfo
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- CN210796292U CN210796292U CN201921747348.1U CN201921747348U CN210796292U CN 210796292 U CN210796292 U CN 210796292U CN 201921747348 U CN201921747348 U CN 201921747348U CN 210796292 U CN210796292 U CN 210796292U
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Abstract
The utility model provides an m-phthalonitrile continuous rectification purification device, which comprises a scraper evaporator and a rectifying tower which are connected in sequence, can realize continuous and stable production and has low operation cost; the device can realize the continuous and stable purification of the isophthalonitrile, obtain the product with the purity of the isophthalonitrile being more than or equal to 99.83 wt%, and reduce the content of cyanobenzamide in the product, thereby reducing the quality of residue in a melter in a chlorothalonil production device, reducing the content of hexachlorobenzene in downstream chlorothalonil products, and relieving the environmental pressure.
Description
Technical Field
The utility model relates to a pesticide refining field especially relates to an m-phthalonitrile continuous rectification purification device.
Background
Isophthalonitrile (IPN) is an important organic raw material for organic synthesis, and is used for preparing plastics, synthetic fibers, pesticides (chlorothalonil), epoxy resin curing agents and the like. Tetrachloroisophthalonitrile synthesized by chlorination of isophthalonitrile is a high-efficiency and low-toxicity bactericide; the m-xylylenediamine prepared by hydrogenation of m-phthalonitrile is an epoxy resin curing agent with excellent performance, and is also a raw material of polyurethane and nylon resin.
At present, the main method for synthesizing isophthalonitrile is an ammoxidation method, namely, m-xylene, ammonia gas and oxygen are subjected to ammoxidation reaction under the action of a catalyst to prepare isophthalonitrile. However, the isophthalonitrile produced by the ammoxidation method has low purity and high amide content, and is crude isophthalonitrile. The crude isophthalonitrile can provide raw materials for subsequent organic synthesis after purification and refining, the main trapping modes of the isophthalonitrile at present are thin-wall trapping and water spraying trapping, but the isophthalonitrile products obtained by the two trapping methods still have high amide content, the high amide content can cause more residues in a melter in the production process of downstream chlorothalonil, and the impurity hexachlorobenzene in the chlorothalonil products can also have high content and great harm to the environment.
CN201384868Y discloses a water spraying and trapping method for trapping and recovering isophthalonitrile in a water mist mode by adopting a spray tower, a secondary absorption tower, a filter press and a drying tower device, which reduces the device investment cost to a certain extent. However, the method adopts a filter press to separate the solid-liquid mixture, the filter press is intermittent equipment and cannot be continuously operated with subsequent drying equipment, and ammonia gas escapes from the filter press in the operation process to greatly influence the labor environment of workers.
CN106892839B discloses a method for refining isophthalonitrile, which comprises the steps of introducing a crude isophthalonitrile raw material into a distillation kettle, cooling steam of the distilled isophthalonitrile through a heat exchanger, introducing into a receiving kettle for heat preservation, and finally slicing through a slicing machine to obtain a refined isophthalonitrile finished product; the method improves the purity of the intermediate phthalonitrile product, but the method adopts the intermittent distillation process to refine the isophthalonitrile, the refined isophthalonitrile product content is only 99.5 percent, and the intermittent process not only easily causes the instability of the product quality, but also is difficult to realize continuous production, and increases the production cost.
CN1202072C discloses a method for refining and purifying isophthalonitrile by adopting a two-stage rectifying tower, which improves the quality and the recovery rate of products; however, the method adopts two-stage rectifying towers, so that the energy consumption is high, the isophthalonitrile has thermal instability, and the modification or deterioration can occur in the primary de-heavy rectification process due to the long rectification time, so that the reactions such as amidation, polymerization and the like are caused, and the yield and the quality of the product are reduced.
In conclusion, the prior art has the problems of high amide content in the isophthalonitrile product, unstable product quality, low yield, difficulty in continuous production and the like, and the high amide content causes more residues in a melter in the production process of downstream chlorothalonil, and causes high content of impurity hexachlorobenzene in the chlorothalonil product and great harm to the environment.
Therefore, it is required to develop a continuous and stable production device of isophthalonitrile with high yield, high purity and low content of m-cyanobenzamide, so as to reduce the content of hexachlorobenzene in the subsequent chlorothalonil product, reduce the residue in a melter in the chlorothalonil production device and reduce the production cost.
SUMMERY OF THE UTILITY MODEL
In view of the problem that exists among the prior art, the utility model provides an isophthalonitrile purification device that rectifies in succession, through using scraper evaporator and rectifying column jointly, make isophthalonitrile raw materials get into the rectifying column middle section after the vaporization in the scraper evaporator and carry out the rectification purification, overcome the problem that isophthalonitrile product quality is unstable and purity is low, can realize continuous stable production, the amide content in manufacturing cost and the product has been reduced, thereby showing the content that has reduced hexachlorobenzene in the clear product of low reaches chlorothalonil, the product quality of chlorothalonil has been improved, the environmental pressure has been alleviated.
To achieve the purpose, the utility model adopts the following technical proposal:
the utility model provides a continuous rectification purification device of isophthalonitrile, the device is including the raw materials supply unit and the purification unit that connect gradually, wherein, the raw materials supply unit includes the scraper blade evaporimeter, the purification unit includes the rectifying column, the pipe connection is passed through with the middle section of rectifying column in the top of scraper blade evaporimeter.
The device provided by the utility model is including the scraper blade evaporimeter and the rectifying column that connect gradually, the device can stabilize continuous operation, and the running cost is low, and wherein, the continuous stable rectifying column middle section that gets into with the gaseous phase form that isophthalonitrile can be ensured between the scraper blade evaporimeter, and the rectifying column can realize the high-efficient separation and the recovery of isophthalonitrile between to obtain high yield and high-purity isophthalonitrile product, showing and having reduced cyanobenzamide content in the middle of the product, thereby reduced the content of hexachlorobenzene in the clear product of low reaches chlorothalonil, improved the clear product quality of chlorothalonil, alleviated ambient pressure.
Preferably, the stirring device is provided inside the scraper evaporator in the raw material supply unit.
The scraper of the scraper evaporator is in the form of a limiting hinge scraper, a flexible scraper, a hinge scraper, an elastic scraper, a scraper type scraper, a movable scraper or a fixed scraper.
The scraper evaporator is provided with a jacket.
And heat conducting oil is adopted for heating in a jacket of the scraper evaporator.
The material of the scraper evaporator is stainless steel, Monel 400 or Hastelloy, and preferably stainless steel 304.
Preferably, the raw material supply unit further comprises a feed metering pump and a melting intermediate tank which are connected in sequence by a pipe.
The utility model discloses a be provided with feeding measuring pump and melting intermediate tank before the scraper evaporator, make the melting of isophthalonitrile raw materials in the melting intermediate tank, play certain cushioning effect, guarantee that the raw materials that get into the scraper evaporator all are flow stability's liquid phase, further hoisting device continuous operation's stability.
The feeding metering pump is a plunger type metering pump.
The melting intermediate tank and the scraper evaporator are connected in sequence.
And the outlet of the melting intermediate tank is provided with a mass flow meter.
The utility model discloses an export in groove sets up mass flow meter in the middle of the melting, can regulate and control the export flow in groove in the middle of the melting, guarantees that the liquid flow that enters into scraper evaporator from groove in the middle of the melting is stable to make the stability of device operation further promote, further guaranteed the purity and the yield of isophthalonitrile product.
The melting intermediate tank is provided with a jacket.
And heat conducting oil is adopted to heat the jacket of the melting intermediate tank.
The material of the melting intermediate tank is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
Preferably, the raw material supply unit further comprises a coke cutting kettle connected with the scraper evaporator.
The utility model discloses a setting is the burnt cauldron of cutting that links to each other with the scraper evaporator, the reation kettle of burnt cauldron for taking the stirring can in time collect the retrieval and utilization with the raw materials that do not vaporize in the scraper evaporator, and prevents scraper evaporator bottom coking, more can promote scraper evaporator's continuous stability.
The top of the coke cutting kettle is connected with the bottom of the scraper evaporator.
And a first valve is arranged on a pipeline connecting the top of the coke cutting kettle and the bottom of the scraper evaporator.
The top of the coke cutting kettle is connected with an outlet pipeline at the top of the scraper evaporator.
And a second valve is arranged on a pipeline connecting the top of the coke cutting kettle and the outlet pipeline at the top of the scraper evaporator.
The top of the coke cutting kettle is respectively connected with the bottom of the scraper evaporator and a top outlet pipeline.
The device provided by the utility model all links to each other with the top outlet pipe way through the top that will cut burnt cauldron and the bottom of scraper blade evaporimeter, wherein, the pipeline that top outlet pipe way links to each other can make the pressure that cuts burnt cauldron and scraper blade evaporimeter communicate with each other, when cutting burnt cauldron pressure and scraper blade evaporimeter pressure the same, communicate scraper blade evaporimeter bottom again and the pipeline at cutting burnt cauldron top, make the complete isophthalonitrile raw materials of non-vaporization flow into and cut burnt cauldron, can realize the intermittent type operation of cutting burnt cauldron, avoid cutting in the burnt cauldron liquid suck-back scraper blade evaporimeter, in order to avoid influencing the quality of isophthalonitrile product and the stability of scraper blade evaporimeter operation.
And a discharge hole is formed in the top of the coke cutting kettle.
And a discharge hole at the top of the coke cutting kettle is provided with a third valve.
The coke cutting kettles are at least two.
The utility model discloses a set up two at least coke cutting kettles, when preventing scraper evaporator bottom coking, reuse in the upper reaches intermittent type technology stills is squeezed into with the raw materials that does not vaporize to the coke cutting kettle of accessible intermittent type in turn operation promotes the utilization ratio of resource.
The coke cutting kettles are divided into two parts, namely a first coke cutting kettle and a second coke cutting kettle.
The coke cutting kettle is provided with a jacket.
And heat conducting oil is adopted in a jacket of the coke cutting kettle for heating.
The material of the coke cutting kettle is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
Preferably, the top of the rectifying tower of the purification unit is provided with an overhead condenser.
The tower top condenser is a shell and tube condenser.
The overhead condenser is provided with a side line extraction outlet.
And a tower bottom reboiler is arranged at the tower bottom of the rectifying tower.
The tower bottom reboiler is a tubular reboiler.
The rectifying tower is internally provided with a filler or a tower plate.
And the outer wall of the rectifying tower is provided with a heat tracing pipe.
The material of the rectifying tower body is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
Preferably, the top outlet of the rectifying tower of the purification unit is provided with a secondary condenser.
The utility model discloses well top of the tower noncondensable gas still contains isophthalonitrile, the utility model provides a device sets up secondary condenser through the top of the tower export at the rectifying column, makes the isophthalonitrile condensation in the top of the tower noncondensable gas become the liquid phase product, has further promoted the yield of isophthalonitrile.
The secondary condenser is a tube type heat exchanger.
And a slag discharging groove is arranged at the outlet of the tower bottom of the rectifying tower.
The device provided by the utility model set up the scum groove bottom the rectifying column, make the high boiling thing of rectifying column bottom in time discharge, reduce the calorific loss of rectifying column bottom and alleviate coking phenomenon, further guarantee the stability of device operation.
The slag discharge groove is provided with a jacket.
And heat conducting oil is adopted to heat the inside of the jacket of the slag discharging groove.
The material of the secondary condenser is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
The material of the slag discharge groove is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
Preferably, the apparatus further comprises a product receiving unit after the purification unit.
The product receiving unit comprises a product receiving kettle connected with the rectifying tower.
The top of the product receiving kettle is connected with a side line outlet of the overhead condenser.
The top of the product receiving kettle is connected with the bottom of the secondary condenser.
The product receiving kettle is provided with a jacket.
And heat conducting oil is adopted to heat the inside of the jacket of the product receiving kettle.
The material of the product receiving kettle is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
Preferably, the bottom of the product receiving kettle in the product receiving unit is provided with a slicing machine or a material beating metering pump.
The ramming metering pump is a plunger type metering pump.
And a product condenser is arranged at the top outlet of the product receiving kettle.
The top of the product condenser, and/or the bottom of the product condenser is connected to the top of the product receiving vessel.
The utility model discloses a top and the bottom with the product condenser receive the top of cauldron simultaneously and link to each other, on the one hand with the product receive in the cauldron not the complete gaseous phase isophthalonitrile of condensation get into the product condenser through the top of product condenser and carry out the condensation and collect, on the other hand returns the product with the isophthalonitrile that the condensation was collected from the bottom of product condenser and receives the cauldron in become isophthalonitrile product, has promoted the yield of isophthalonitrile.
The material of the product condenser is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
Preferably, the product receiving unit is provided with a product catcher at the top of the product receiving vessel.
A baffle is arranged inside the product catcher.
And a gas phase outlet of the product catcher is provided with a filter screen.
The product traps are provided in at least two.
The number of the product traps is two, namely a first product trap and a second product trap.
The product catcher is provided with the jacket all around.
And circulating cooling water, cold air, low-temperature water or frozen brine is introduced into a jacket of the product catcher.
The product catcher is made of carbon steel or stainless steel.
The product catcher is connected with a vacuum pump.
The vacuum pump is a water ring vacuum pump, a piston type vacuum pump or a Roots vacuum pump, and preferably is a water ring vacuum pump.
The vacuum pump is made of carbon steel or stainless steel.
Preferably, the connecting pipelines among the product receiving kettles in the raw material supply unit, the purification unit and the product receiving unit are all jacketed pipelines.
The material of the jacket pipeline is stainless steel, Monel 400 or Hastelloy, and stainless steel 304 is preferred.
The device provided by the utility model can adopt following technology to go on:
(1) introducing an m-phthalonitrile raw material into a melting intermediate tank with the temperature of 150-260 ℃ for melting;
(2) vaporizing the isophthalonitrile raw material flowing out of the melting intermediate tank in a scraper evaporator with the temperature of 220-310 ℃ and the vacuum degree of 0.07-0.098 MPa, intermittently flowing liquid-phase isophthalonitrile incompletely vaporized in the scraper evaporator into at least two coke cutting kettles with the temperature of 150-260 ℃, and collecting for later use;
(3) introducing the vaporized isophthalonitrile in the scraper evaporator into the middle section of a rectifying tower, rectifying and purifying to obtain purified isophthalonitrile, extracting liquid-phase phthalonitrile from a side line extraction outlet of a condenser at the top of the rectifying tower, introducing non-condensable gas at the top of the rectifying tower into a secondary condenser for secondary condensation, putting high-boiling-point substances at the bottom of the rectifying tower into a slag discharge tank, periodically discharging slag and barreling, wherein the vacuum degree of the rectifying tower is 0.07-0.098 MPa, the temperature of the rectifying section is 150-210 ℃, the temperature of the stripping section is 220-310 ℃, the temperature of the condenser at the top of the rectifying tower is 150-210 ℃, the temperature of a reboiler at the bottom of the tower is 220-310 ℃, the temperature of the secondary condenser is 150-210 ℃ and the temperature of the slag discharge tank is 220-310 ℃;
(4) and introducing the liquid-phase phthalonitrile extracted from the side draw outlet of the overhead condenser and the liquid-phase phthalonitrile extracted from the bottom of the secondary condenser into a product receiving kettle with the temperature of 150-210 ℃ and the vacuum degree of 0.07-0.098 MPa, and extracting an isophthalonitrile product from the bottom of the product receiving kettle.
Compared with the prior art, the utility model discloses following beneficial effect has at least:
(1) the utility model provides a continuous rectification purification device of m-phthalonitrile, through alling oneself with scraper evaporator and rectifying column with, can improve the content of phthalonitrile in the middle of the product and keep more than or equal to 99.83 wt% of the stable more than or equal to of purity of m-phthalonitrile, the mole yield is more than or equal to 98.1%;
(2) the utility model provides a continuous rectification purification device of m-phthalonitrile, through making m-phthalonitrile evaporate the rectification purification in scraper evaporator and rectifying column in succession, can be with the product in the middle of the cyanobenzamide content by 2.55 wt% before the refining fall to be less than or equal to 0.11 wt%, the residue formation volume of melting kettle in the clear production of low reaches chlorothalonil has significantly reduced to the content of hexachlorobenzene in the clear product of low reaches chlorothalonil is as low as 10ppm, has improved the clear product quality of chlorothalonil, has alleviated ambient pressure;
(3) the utility model provides a continuous rectification purification device of m-phthalonitrile can realize continuous production through scraper evaporator and rectifying column, and product quality is stable, and the running cost is low.
Drawings
FIG. 1 is a drawing of a device for continuous rectification and purification of isophthalonitrile provided by the embodiment of the utility model 1.
In the figure: 1-plunger type feeding metering pump; 2-melting the intermediate tank; 3-a scraper evaporator; 4-a first coke cutting kettle; 5-a second coke cutting kettle; 6-a continuous rectification column; 7-a tube array type secondary condenser; 8-a shell and tube product condenser; 9-a product receiving kettle; 10-plunger type material beating metering pump; 11-a slag discharge groove; 12-a first product trap; 13-a second product trap; 14-a first water-ring vacuum pump; 15-second water-ring vacuum pump.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings. However, the following embodiments are only simple examples of the present invention, and do not represent or limit the scope of the present invention, which is defined by the appended claims.
First, an embodiment
Example 1
This example provides an isophthalonitrile continuous distillation purification apparatus, as shown in fig. 1, comprising a raw material supply unit, a purification unit and a product receiving unit connected in sequence, wherein,
the raw material supply unit includes: the raw material supply unit includes: a plunger type feeding metering pump 1, a melting intermediate tank 2, a scraper evaporator 3, a first coke cutting kettle 4 and a second coke cutting kettle 5; wherein the plunger type feeding metering pump 1, the melting intermediate tank 2 and the scraper evaporator 3 are sequentially connected, a stirring device is arranged in the scraper evaporator, the scraper is in a limiting hinge scraper form, the bottom of the scraper evaporator 3 is respectively connected with the tops of the first coke cutting kettle 4 and the second coke cutting kettle 5, a first valve, namely a valve V3 and a valve V6, is arranged on a connecting pipeline, the tops of the first coke cutting kettle 4 and the second coke cutting kettle 5 are also connected with an outlet pipeline of the scraper evaporator 3, a second valve, namely a valve V1 and a valve V4, is arranged on the connecting pipeline, a discharge outlet is arranged at the top of the first coke cutting kettle 4 and the second coke cutting kettle 5, a third valve, namely a valve V2 and a valve V5, is arranged at the discharge outlet, the melting intermediate tank 2, the scraper evaporator 3, the first coke cutting kettle 4 and the second coke cutting kettle 5 are all made of stainless steel 304, the periphery of the plunger type feeding metering pump 1 is provided with a jacket for heat preservation, heat conducting oil is adopted in the jacket for heating, connecting pipelines among the plunger type feeding metering pump 1, the melting intermediate tank 2, the scraper evaporator 3, the first coke cutting kettle 4 and the second coke cutting kettle 5 are all jacket pipelines, and the materials of the jacket pipelines are all stainless steel 304;
the purification unit includes: a rectifying tower 6, a tube array type secondary condenser 7 and a slag discharge groove 11; the middle section of the rectifying tower 6 is connected with the top of a scraper evaporator 3 of a raw material supply unit, a tubular tower top condenser is arranged at the tower top, a side line extraction port is arranged on the tower top condenser, a tubular secondary condenser 7 is arranged at the tower top outlet of the rectifying tower 6, a tubular tower bottom reboiler is arranged at the tower bottom, packing is filled in the rectifying tower, a heat tracing pipe is arranged on the outer wall of the rectifying tower, a slag discharge groove 11 is arranged at the tower bottom outlet of the rectifying tower, a jacket is arranged around the slag discharge groove 11 for heat preservation, heat conduction oil is adopted in the jacket for heating, connecting pipelines among the scraper evaporator 3, the rectifying tower 6 and the tubular secondary condenser 7 are all jacket pipelines, and the jacket pipelines, a tower body of the rectifying tower 6, the tubular secondary condenser 7 and the slag discharge groove 11 are all made of stainless steel;
the product receiving unit includes: a tubular product condenser 8, a product receiving kettle 9, a plunger type material beating metering pump 10, a first product catcher 12, a second product catcher 13, a first water ring vacuum pump 14 and a second water ring vacuum pump 15, wherein the top of the product receiving kettle 9 is simultaneously connected with a side line outlet of a tubular tower top condenser of a rectifying tower 6 of a purifying unit and the bottom of a tubular secondary condenser 7, the plunger type material beating metering pump 10 is arranged at the bottom of the product receiving kettle 9, the tubular product condenser 8 is arranged at a top outlet, the top and the bottom of the tubular product condenser 8 are respectively connected with the top of the product receiving kettle 9, a baffle is arranged inside the top connection, the first product catcher 12 and the second product catcher 13 of a filter screen are arranged at a gas phase outlet, the first product catcher 12 is connected with the first water ring vacuum pump 14, the second product catcher 13 is connected with the second water-ring vacuum pump 15, the product receiving kettle 9 is provided with a jacket around for heat preservation, heat conducting oil is adopted for heating in the jacket, the first product catcher 12 and the second product catcher 13 are provided with a jacket around, circulating cooling water is introduced into the jacket, the tubular product condenser 8, the product receiving kettle 9, the first water-ring vacuum pump 14 and the second water-ring vacuum pump 15 are all made of stainless steel 304, and the first product catcher 12 and the second product catcher 13 are made of carbon steel.
Example 2
The embodiment provides an isophthalonitrile continuous rectification and purification device, which comprises a raw material supply unit, a purification unit and a product receiving unit which are connected in sequence, wherein,
the raw material supply unit includes: a plunger type feeding metering pump 1, a scraper evaporator 3, a first coke cutting kettle 4 and a second coke cutting kettle 5; wherein the plunger type feeding metering pump 1 and the scraper evaporator 3 are sequentially connected, a stirring device is arranged in the scraper evaporator, the scraper is in the form of a limiting hinge scraper, the bottom of the scraper evaporator 3 is respectively connected with the tops of the first coke cutting kettle 4 and the second coke cutting kettle 5, a first valve, namely a valve V3 and a valve V6, is arranged on a connecting pipeline, the tops of the first coke cutting kettle 4 and the second coke cutting kettle 5 are also connected with an outlet pipeline of the scraper evaporator 3, a second valve, namely a valve V1 and a valve V4, is arranged on the connecting pipeline, a discharge port is arranged at the top of the first coke cutting kettle 4 and the top of the second coke cutting kettle 5, a third valve, namely a valve V2 and a valve V5, the scraper evaporator 3, the first coke cutting kettle 4 and the second coke cutting kettle 5 are all made of stainless steel 304, a jacket is arranged around the periphery of the scraper evaporator and the jacket is heated by heat conducting oil, connecting pipelines among the plunger type feeding metering pump 1, the scraper evaporator 3, the first coke cutting kettle 4 and the second coke cutting kettle 5 are all jacket pipelines, and the jacket pipelines are all made of stainless steel 304;
the purification unit and the product receiving unit are identical in arrangement and connection to those of example 1, that is, the same as example 1 except for the melting intermediate tank not including the raw material supply unit of example 1 and the corresponding connection.
Comparative example 1
This comparative example provides an isophthalonitrile purification apparatus, and compared with example 1, the raw material supply unit provided by this comparative example was the same as that of example 1 except that the scraper evaporator in example 1 was replaced with a flash evaporator.
Comparative example 2
Compared with the embodiment 1, the comparison example provides an isophthalonitrile purification device, omits the rectifying tower in the embodiment 1, directly connects the top of the scraper evaporator with the top of the tubular secondary condenser, and the rest is the same as the embodiment 1.
Second, application
Application example 1
The application example provides a method for performing isophthalonitrile continuous rectification purification by using the device in the embodiment 1, and the method comprises the following steps:
(1) continuously introducing an m-phthalonitrile raw material from a batch distillation process receiving kettle into a melting intermediate tank 2 with the temperature of 150 ℃ through a plunger type feeding metering pump 1 for melting;
(2) vaporizing the isophthalonitrile raw material flowing out of the melting intermediate tank 2 in a scraper evaporator 3 with the temperature of 220 ℃ and the vacuum degree of 0.095MPa, intermittently and alternately flowing liquid-phase isophthalonitrile incompletely vaporized in the scraper evaporator 3 into a first coke cutting kettle 4 and a second coke cutting kettle 5 with the temperature of 150 ℃, and collecting for later use;
(3) introducing the vaporized isophthalonitrile in the scraper evaporator 3 into the middle section of a rectifying tower 6, rectifying and purifying to obtain purified isophthalonitrile, extracting liquid-phase phthalonitrile from a side line extraction port of a condenser at the top of the rectifying tower 6, introducing non-condensable gas at the top of the rectifying tower into a tubular secondary condenser 7 for secondary condensation, putting high-boiling-point substances at the bottom of the rectifying tower into a slag discharge groove 11, regularly discharging slag and barreling, wherein the vacuum degree of the rectifying tower 6 is 0.095MPa, the rectifying section temperature of the rectifying tower is 210 ℃, the stripping section temperature is 310 ℃, the temperature of the tubular overhead condenser is 210 ℃, the temperature of a reboiler at the bottom of the tubular tower is 310 ℃, the temperature of the tubular secondary condenser 7 is 210 ℃ and the temperature of the slag discharge groove 11 is 310 ℃;
(4) introducing liquid-phase isophthalonitrile extracted from a side extraction port of the overhead condenser and extracted from the bottom of the tubular secondary condenser 7 into a product receiving kettle 9 with the vacuum degree of 0.095MPa and the temperature of 150 ℃, extracting an isophthalonitrile product from the bottom of the product receiving kettle 9, and introducing the isophthalonitrile product into a chlorothalonil workshop through slicing by a slicer or through a plunger type knockout metering pump 10;
(5) introducing the m-phthalonitrile which is not completely condensed in the product receiving kettle 9 into a tubular product condenser 8 at the temperature of 120 ℃ for secondary condensation, returning the condensed liquid phase m-phthalonitrile in the tubular product condenser 8 into the product receiving kettle as a liquid phase product, and collecting the uncondensed tail gas in the tubular product condenser 8 into solid powder through a first product catcher 12 and a second product catcher 13 at the temperature of 90 ℃ under the vacuum degree of 0.095MPa, thereby obtaining a qualified product.
According to the application example, the device provided by the embodiment 1 is adopted to produce the isophthalonitrile, the purity of the obtained isophthalonitrile product is 99.85 wt%, the molar yield is 98.5%, and the isophthalonitrile produced by the application example is adopted to produce downstream chlorothalonil, so that the content of hexachlorobenzene in the chlorothalonil product is reduced to 10ppm, and the product quality of the chlorothalonil is improved.
Application example 2
The present application example provides a method for performing continuous rectification and purification of isophthalonitrile by using the apparatus described in example 2, which is different from application example 1 in that the melting operation of isophthalonitrile is not performed, and an isophthalonitrile raw material is directly introduced into a scraper evaporator, and the method specifically includes the following steps:
(1) continuously introducing an isophthalonitrile raw material from a receiving kettle of the batch distillation process into a scraper evaporator 3 through a plunger type feeding metering pump 1;
(2) vaporizing the isophthalonitrile raw material in a scraper evaporator 3 with the temperature of 220 ℃ and the vacuum degree of 0.095MPa, intermittently and alternately flowing incompletely vaporized liquid-phase isophthalonitrile in the scraper evaporator 3 into a first coke cutting kettle 4 and a second coke cutting kettle 5 with the temperature of 150 ℃, and collecting for later use;
the operation steps and process parameters in step (3), step (4) and step (5) are the same as those in application example 1.
Application comparative example 1
Comparative example of the present application provides a method for purifying isophthalonitrile using the apparatus described in comparative example 1, differing from application example 1 only in that a blade evaporator was replaced with a flash evaporator, and the remaining operational steps and process parameters were the same as in application example 1, wherein the specific steps for the flash evaporator in step (2) were as follows:
(2) vaporizing the isophthalonitrile raw material flowing out of the melting intermediate tank 2 in a flash evaporator with the temperature of 220 ℃ and the vacuum degree of 0.095MPa, intermittently and alternately flowing liquid-phase isophthalonitrile incompletely vaporized in the flash evaporator into a first coke cutting kettle 4 and a second coke cutting kettle 5 with the temperature of 150 ℃, and collecting for later use; the switching operation steps of the first coke cutting kettle 4 and the second coke cutting kettle 5 are the same as those of application example 1.
Comparative application example 2
Compared with the application example 1, the method for purifying the isophthalonitrile by using the device in the comparative example 2 omits the rectification process, directly introduces the isophthalonitrile vaporized in the scraper evaporator into the condenser for condensation and recovery, and specifically replaces the steps (3) to (4) in the application example 1 with the following steps:
(3) introducing the vaporized isophthalonitrile in the scraper evaporator 3 into a secondary condenser 7 for secondary condensation, wherein the temperature of the secondary condenser 7 is 210 ℃;
(4) introducing the liquid-phase isophthalonitrile extracted from the bottom of the secondary condenser 7 into a product receiving kettle 9 with the vacuum degree of 0.095MPa and the temperature of 150 ℃, extracting an isophthalonitrile product from the bottom of the product receiving kettle 9, and introducing the isophthalonitrile product into a chlorothalonil workshop through slicing by a slicer or through a plunger type knockout metering pump 10;
the remaining steps and operating parameters were the same as in application example 1.
The utility model provides an application example 1 ~ 2 and application comparative example 1 ~ 2 handle the isophthalonitrile raw materials, carry out the analysis to the isophthalonitrile product and the isophthalonitrile rate of recovery of gained, the analysis result is shown as table 1.
TABLE 1
From table 1, the following points can be seen:
(1) it can be seen from comprehensive application example 1 and application example 2 that, the utility model provides an m-phthalonitrile continuous rectification purification device uses in the purification of m-phthalonitrile, and the product purity of the m-phthalonitrile who makes is greater than or equal to 99.83 wt%, and wherein the content of middle cyanobenzamide is less than or equal to 0.11 wt%, and the content of terephthalonitrile is less than or equal to 0.04 wt%, makes the hexachlorobenzene content in low reaches chlorothalonil low to 10ppm, and the molar yield of m-phthalonitrile is greater than or equal to 98.1% simultaneously, explains to adopt the utility model provides an m-phthalonitrile continuous rectification purification device carries out the rectification purification to m-phthalonitrile, not only can stabilize continuous production, but also can obtain higher m-phthalonitrile product purity and rate of recovery;
(2) by integrating application example 1 and application comparative example 1, it can be seen that, in application example 1, by arranging the scraper evaporator in front of the rectifying tower, compared with the application comparative example 1 adopting the flash evaporator, the purity of the isophthalonitrile product obtained in application example 1 is 99.85 wt%, the molar recovery rate is 98.5%, and the purity of the isophthalonitrile product obtained in application comparative example 1 is only 99.35 wt%, and the molar yield is only 97.1%, so that the utility model discloses an application of the scraper evaporator to evaporate isophthalonitrile has a higher heat exchange coefficient, so that the isophthalonitrile has a shorter retention time, coking and deterioration of the thermosensitive isophthalonitrile are reduced, and the purity and yield of the final isophthalonitrile product are improved;
(3) by combining application example 1 and application comparative example 2, it can be seen that application example 1 can be better separated from impurities in the raw material by adding a rectifying tower after the scraper evaporator, compared with application comparative example 2 which only uses a scraper evaporator, the purity of the isophthalonitrile product obtained in application example 1 is 99.85 wt%, the content of m-cyanobenzamide is only 0.09 wt%, the content of terephthalonitrile is only 0.04 wt%, and the molar recovery rate of the isophthalonitrile product is 98.5%, while the purity of the product in application comparative example 2 is only 99.51 wt%, the content of m-cyanobenzamide is up to 0.32 wt%, the content of terephthalonitrile is up to 0.15 wt%, and the molar yield of the isophthalonitrile product is only 98.1%, by adding a rectifying tower after the scraper evaporator, the isophthalonitrile is rectified and purified after vaporization, the content of the intermediate cyanobenzamide in the product is reduced, and the isophthalonitrile product with higher purity is obtained.
To sum up, the utility model provides a product purity of isophthalonitrile that isophthalonitrile continuous rectification purification device made is more than or equal to 99.83 wt%, and the content of its middle cyanobenzamide is less than or equal to 0.11 wt%, makes hexachlorobenzene content only be 10ppm in the low reaches chlorothalonil, and the molar yield of isophthalonitrile simultaneously is more than or equal to 98.1%, has reduced the content of cyanobenzamide in the middle of the product effectively, and the device can stabilize continuous production moreover, low in production cost has higher industrial application and worth.
The applicant states that the present invention is described by the above embodiments, but the present invention is not limited to the above detailed structural features, i.e. the present invention can be implemented only by relying on the above detailed structural features. It should be clear to those skilled in the art that any modifications to the present invention, to the equivalent replacement of selected parts and the addition of auxiliary parts, the selection of specific modes, etc., all fall within the scope of protection and disclosure of the present invention.
Claims (10)
1. The device for continuously rectifying and purifying the isophthalonitrile is characterized by comprising a raw material supply unit and a purification unit which are sequentially connected;
the raw material supply unit comprises a scraper evaporator;
the purification unit comprises a rectifying tower;
the top of the scraper evaporator is connected with the middle section of the rectifying tower through a pipeline.
2. The isophthalonitrile continuous distillation purification apparatus according to claim 1, wherein a stirring device is provided inside a scraper evaporator in the raw material supply unit;
the scraper of the scraper evaporator is in the form of a limiting hinge scraper, a flexible scraper, a hinge scraper, an elastic scraper, a scraper type scraper, a movable scraper or a fixed scraper;
the scraper evaporator is provided with a jacket.
3. The isophthalonitrile continuous distillation purification apparatus according to claim 1 or 2, wherein the raw material supply unit further comprises a feed metering pump and a melting intermediate tank which are connected in sequence by a pipe;
the feeding metering pump is a plunger type metering pump;
the melting intermediate tank and the scraper evaporator are sequentially connected;
the melting intermediate tank is provided with a jacket.
4. The isophthalonitrile continuous distillation purification plant according to claim 1 or 2, wherein the raw material supply unit further comprises a coke cutting kettle connected with the scraper evaporator;
the top of the coke cutting kettle is connected with the bottom of the scraper evaporator;
the top of the coke cutting kettle is connected with an outlet pipeline at the top of the scraper evaporator;
a discharge hole is formed in the top of the coke cutting kettle;
the number of the coke cutting kettles is at least two;
the coke cutting kettle is provided with a jacket.
5. The isophthalonitrile continuous distillation purification device according to claim 1, wherein an overhead condenser is arranged at the top of the rectification column of the purification unit;
the tower top condenser is a shell and tube condenser;
the tower top condenser is provided with a side line extraction outlet;
a tower bottom reboiler is arranged at the tower bottom of the rectifying tower;
the tower bottom reboiler is a tube type reboiler;
a filler or a tower plate is arranged in the rectifying tower;
and the outer wall of the rectifying tower is provided with a heat tracing pipe.
6. The isophthalonitrile continuous distillation purification device according to claim 5, wherein a secondary condenser is arranged at the top outlet of the rectifying tower of the purification unit;
the secondary condenser is a tube type heat exchanger;
a slag discharging groove is formed in the outlet of the tower bottom of the rectifying tower;
the slag discharge groove is provided with a jacket.
7. The isophthalonitrile continuous distillation purification plant according to claim 6, further comprising a product receiving unit after the purification unit;
the product receiving unit comprises a product receiving kettle connected with the rectifying tower;
the top of the product receiving kettle is connected with a side line outlet of the overhead condenser;
the top of the product receiving kettle is connected with the bottom of the secondary condenser;
the product receiving kettle is provided with a jacket.
8. The isophthalonitrile continuous distillation purification device according to claim 7, wherein a slicer or a material-beating metering pump is arranged at the bottom of the product receiving kettle in the product receiving unit;
the ramming metering pump is a plunger type metering pump;
a product condenser is arranged at the top outlet of the product receiving kettle;
the top of the product condenser, and/or the bottom of the product condenser is connected to the top of the product receiving vessel.
9. The isophthalonitrile continuous distillation purification device according to claim 7 or 8, wherein a product catcher is arranged at the top of a product receiving kettle in the product receiving unit;
a baffle is arranged inside the product catcher;
a gas phase outlet of the product catcher is provided with a filter screen;
the number of the product traps is at least two;
the periphery of the product catcher is provided with a jacket;
the product catcher is connected with a vacuum pump;
the vacuum pump is a water ring vacuum pump, a piston type vacuum pump or a Roots vacuum pump.
10. The isophthalonitrile continuous distillation purification device according to claim 7, wherein the connecting pipes between the product receiving tanks in the raw material supply unit, the purification unit and the product receiving unit are all jacketed pipes.
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| CN201921747348.1U CN210796292U (en) | 2019-10-17 | 2019-10-17 | Continuous rectification and purification device for m-phthalonitrile |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921747348.1U CN210796292U (en) | 2019-10-17 | 2019-10-17 | Continuous rectification and purification device for m-phthalonitrile |
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| CN210796292U true CN210796292U (en) | 2020-06-19 |
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