CN113731339B - P-xylene oxidation crystallization device - Google Patents
P-xylene oxidation crystallization device Download PDFInfo
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- CN113731339B CN113731339B CN202111310286.XA CN202111310286A CN113731339B CN 113731339 B CN113731339 B CN 113731339B CN 202111310286 A CN202111310286 A CN 202111310286A CN 113731339 B CN113731339 B CN 113731339B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J4/00—Feed or outlet devices; Feed or outlet control devices
- B01J4/001—Feed or outlet devices as such, e.g. feeding tubes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0018—Evaporation of components of the mixture to be separated
- B01D9/0022—Evaporation of components of the mixture to be separated by reducing pressure
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/18—Stationary reactors having moving elements inside
- B01J19/20—Stationary reactors having moving elements inside in the form of helices, e.g. screw reactors
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
- C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
- C07C51/265—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting having alkyl side chains which are oxidised to carboxyl groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
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Abstract
The invention discloses a p-xylene oxidation crystallization device, and relates to the technical field of chemical industry. The device comprises an oxidation reactor, a dehydration tower, a first slurry tank, a centrifugal machine, a pulping tank, a rotary vacuum filter, a drying machine, a storage bin, a hopper and a second slurry tank, wherein the dehydration tower is connected with the oxidation reactor through a pipeline, the first slurry tank is connected with the oxidation reactor through a discharge pipe, the centrifugal machine, the pulping tank, the rotary vacuum filter and the drying machine are connected through a conveying pipeline, and the rotary vacuum filter is connected with the oxidation reactor through a connecting pipe. Compared with the oxidation reactor of the comparison document, the invention can uniformly guide the reflux liquid to the inner wall of the oxidation reactor through the arranged liquid distribution disc, so that the reactant is not easy to scale on the inner wall of the oxidation reactor, the arranged downcomer effectively increases the liquid flow length, increases the gas-liquid contact time and improves the mass transfer efficiency of the tower plate.
Description
Technical Field
The invention relates to the technical field of chemical industry, in particular to a p-xylene oxidation crystallization device.
Background
Para-xylene is an organic compound, one of the important aromatic hydrocarbon products, and is a colorless transparent liquid with aromatic flavor at normal temperature. Insoluble in water and soluble in ethanol, ether, chloroform and other organic solvents. The method is mainly used for Preparing Terephthalic Acid (PTA) and dimethyl terephthalate (DMT) so as to produce polyethylene terephthalate (PET), and can also be used as a solvent and a production raw material of medicines, spices, printing ink and the like, so that the method has wide application.
The Chinese patent with the publication number of CN101817744A discloses a p-xylene oxidation crystallization device, which specifically discloses that the crystallization device comprises an oxidation reaction device, a crystallization device and a filtering separation device which are connected in sequence, wherein the oxidation reaction device adopts a full-mixing oxidation reactor, a feed inlet and an air inlet of the oxidation reactor are respectively arranged on the side wall of a shell of the oxidation reactor, the air inlet is positioned below the feed inlet, a discharge outlet of the oxidation reactor is positioned below the feed inlet, a certain interval is kept between the discharge outlet and the feed inlet in the vertical direction, the discharge outlet and the feed inlet can be generally arranged at the bottom of the shell of the oxidation reactor, an air flow distribution device connected with the air inlet is arranged in the shell, the air flow distribution device is provided with a plurality of air outlets, and the air outlets are positioned below the feed inlet. The design can avoid the short circuit phenomenon of feeding and discharging in the material oxidation reaction, improve the oxidation crystallization effect of p-xylene, and simultaneously recover the energy of crystallization cooling, thereby not only saving the equipment cost and the occupied area, but also realizing the effective recovery of energy.
However, in the oxidation reactor, the stirring condition is crucial to control CTA crystal formation and avoid scaling of the inner wall of the reactor, but in the reaction of the oxidation reactor in the above application document, firstly, the reaction product is easy to accumulate scaling on the inner wall of the reactor, thereby affecting the reaction efficiency, and secondly, most of the downcomers in the dehydration tower used in cooperation with the oxidation reactor are vertical arc-shaped downcomers, and the adoption of the downcomers enables the gas-liquid flow which is unevenly distributed on the tray to be easily formed, so that the invention provides a novel solution.
Disclosure of Invention
The invention aims to provide a p-xylene oxidation crystallization device to solve the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme: a p-xylene oxidation crystallization device comprises an oxidation reactor, a dehydration tower, a first slurry tank, a centrifugal machine, a pulping tank, a rotary vacuum filter, a dryer, a storage bin, a hopper and a second slurry tank, wherein the dehydration tower is connected with the oxidation reactor through a pipeline, the first slurry tank is connected with the oxidation reactor through a discharge pipe, the centrifugal machine, the pulping tank, the rotary vacuum filter and the dryer are connected through a conveying pipeline, the rotary vacuum filter is connected with the oxidation reactor through a connecting pipe, one side of the second slurry tank is also connected with a hydrogenation reactor, one side of the hydrogenation reactor is sequentially provided with a first crystallizer, a second crystallizer and a third crystallizer which are connected in series, the first crystallizer is connected with the hydrogenation reactor through a pipeline, one side of the oxidation reactor is connected with a feeding pipe for feeding, and the bottom of the oxidation reactor is provided with an integrally formed air inlet, install the inlet structure in the air inlet, oxidation reactor bottom is connected with the discharge pipe, be provided with the agitator in the oxidation reactor and install the liquid distribution dish on oxidation reactor top, the liquid distribution dish includes the disk body, the disk body top is the frustum form, and disk body upper surface equidistant is equipped with a plurality of V word water conservancy diversion structures, V word water conservancy diversion structure includes first water conservancy diversion swash plate and second water conservancy diversion swash plate, be formed with V word water conservancy diversion canal between first water conservancy diversion swash plate and the second water conservancy diversion swash plate, a plurality of air vents have been seted up on the disk body, disk body bottom slope is provided with a plurality of water conservancy diversion bottom plates, water conservancy diversion bottom plate equidistant setting, and the guiding gutter has all been seted up on the water conservancy diversion bottom plate, be equipped with a plurality of water conservancy diversion extension boards between disk body and the water conservancy diversion bottom plate, water conservancy diversion extension board bottom contacts with the guiding gutter, liquid distribution dish middle part is formed with the circular chamber that supplies the agitator to pass.
As preferred technical scheme in this application, the agitator includes the puddler of vertical setting in oxidation reactor, installs two fixing bases on the puddler, installs a convection current flight on a fixing base, installs end convection current flight on another fixing base, and the helicla flute has all been seted up on top convection current flight and the end convection current flight, and the symmetry sets up between top convection current flight and the end convection current flight, and oxidation reactor top installation motor, motor output end are fixed mutually with the top of puddler.
As preferred technical scheme in this application, the water content detector is installed to oxidation reactor bottom, and the inside detection chamber that is provided with of water content detector installs the inlet tube on the water content detector, is equipped with the water pump on the inlet tube, and oxidation reactor bottom is arranged in to inlet tube one end, still is equipped with the medicament pipe on the water content detector, is equipped with total controller on the oxidation reactor, through electric connection between total controller and the water content detector.
As the preferable technical scheme in the application, the paraxylene oxidation crystallization device comprises an oxidation reactor, wherein an infrared carbon dioxide analyzer is installed at the top end of the oxidation reactor, a high-pressure hose is installed on the infrared carbon dioxide analyzer and used for conveying carbon dioxide, and the infrared carbon dioxide analyzer is electrically connected with a master controller.
The invention relates to a p-xylene oxidation crystallization device, which is a preferable technical scheme in the application, wherein a plurality of oxygen analyzers are arranged on an oxidation reactor, and the oxygen analyzers are electrically connected with a master controller.
As the preferable technical scheme in the application, a plurality of layers of tower trays are arranged in the dehydration tower, downcomers are connected among the tower trays, the downcomers incline to the inner wall of the dehydration tower from top to bottom, the widths of the downcomers are sequentially reduced from top to bottom, the bottom of each downcomer forms a long and thin strip shape, and the inner cavity of each downcomer is gradually enlarged from bottom to top.
As the preferred technical scheme in this application, the downcomer side equidistance is connected with a plurality of drainage pieces, and the drainage piece transversal personally submits isosceles trapezoid, and has all seted up the drainage groove on the drainage piece, installs a plurality of triangle-shaped floating valves, rectangle composite hole standing valve and tympanic bulla promoter on the tower tray.
As the preferable technical scheme in the application, an air supply system is connected between the bin and the hopper, and a spiral feeder is connected between the hopper and the second slurry tank.
Compared with the prior art, the invention has the beneficial effects that:
(1) compared with an oxidation reactor of a comparison document, the p-xylene oxidation crystallization device can uniformly guide reflux liquid to the inner wall of the oxidation reactor through the arranged liquid distribution disc, so that reactants are not easy to scale on the inner wall of the oxidation reactor, the arranged stirrer can ensure good airflow stirring and maintain particle suspension, and the efficiency of the oxidation reactor is higher.
(2) This p-xylene oxidation crystallization device, vertical bow-shaped and slope bow-shaped downcomer in comparing in traditional dehydration tower can lead to easily forming unevenly distributed gas-liquid flow on the tray, and this downcomer makes liquid flow distribute evenly, and rivers can not appear breaking cliff formula whereabouts, and the downcomer inner wall is prolonged along whole weir length from bottom to top gradually to make ascending gas along tray lateral distribution even, this kind of downcomer has increased liquid flow length effectively, has increased the gas-liquid contact time, thereby has improved the mass transfer efficiency of tray.
(3) This p-xylene oxidation crystallization device, water content detector through setting up, mutually supporting of inlet tube and water pump etc, the water content in the detection acetic acid that can be strict, thereby guarantee the water content in the reactor, guarantee that the high efficiency of reaction goes on, the infrared carbon dioxide analysis appearance of setting, can detect the content of the carbon dioxide in the tail gas, thereby can be used for surveing the combustion degree of acetic acid and p-xylene, in addition, through the continuous determination to carbon dioxide content, can be used for strict representation reaction condition, and also be used for warning the inside conflagration that probably takes place.
Drawings
FIG. 1 is a first perspective view of the present invention;
FIG. 2 is a second perspective view of the present invention;
FIG. 3 is a schematic perspective view of an oxidation reactor according to the present invention;
FIG. 4 is a schematic illustration of a split configuration of an oxidation reactor of the present invention;
FIG. 5 is a schematic view of a first perspective view of the liquid distribution tray of the present invention;
FIG. 6 is a schematic view of a second perspective view of the liquid distribution tray of the present invention;
FIG. 7 is an enlarged view of part A of the present invention;
FIG. 8 is a schematic perspective view of the agitator of the present invention;
FIG. 9 is a schematic view of an assembled structure of trays and downcomers in a dehydration column of the present invention;
FIG. 10 is a schematic perspective view of a tray and downcomer in a dehydration column of the present invention;
FIG. 11 is an enlarged view of part B of the present invention.
In the figure: 1. an oxidation reactor; 101. a discharge pipe; 102. a connecting pipe; 103. an air inlet; 104. a feed pipe; 2. a dehydration tower; 201. a tray; 202. a downcomer; 203. a drainage sheet; 204. a drainage groove; 3. a first slurry tank; 4. a centrifuge; 5. a pulping tank; 6. rotating the vacuum filter; 7. a dryer; 8. a storage bin; 9. a hopper; 10. a second slurry tank; 11. a water content detector; 1101. a water inlet pipe; 1102. a water pump; 12. an infrared carbon dioxide analyzer; 13. a liquid distribution tray; 1301. a tray body; 1302. a first flow guiding sloping plate; 1303. a second flow guiding inclined plate; 1304. a vent hole; 1305. a flow guide bottom plate; 1306. a diversion trench; 1307. a flow guide support plate; 1308. a circular lumen; 14. a stirrer; 1401. a stirring rod; 1402. a motor; 1403. a fixed seat; 1404. a bottom convection flight; 1405. a top convection spiral sheet.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that in the description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience of description and simplification of description, and do not indicate or imply that the referred device or element must have a specific orientation, be configured in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Further, it will be appreciated that the dimensions of the various elements shown in the figures are not drawn to scale, for ease of description, and that the thickness or width of some layers may be exaggerated relative to other layers, for example.
It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined or illustrated in one figure, it will not need to be further discussed or illustrated in detail in the description of the following figure.
As shown in fig. 1 to 8, the present invention provides a technical solution: a p-xylene oxidation crystallization device comprises an oxidation reactor 1, one side of the oxidation reactor 1 is connected with a feeding pipe 104 for feeding, p-xylene, acetic acid solvent, cobalt acetate, manganese acetate catalyst and tetrabromoethane cocatalyst enter the oxidation reactor 1 through the feeding pipe 104, air (mixed gas of air and pure oxygen) enters the oxidation reactor 1 from an air inlet 103 at the bottom of the oxidation reactor 1 under the flow control, the oxidation reactor 1 is provided with an integrally formed air inlet 103 at the bottom, an air inlet structure is installed in the air inlet 103, a discharge pipe 101 is connected with the bottom of the oxidation reactor 1, the oxidation reactor 1 is provided with a stirrer 14 and a liquid distribution disk 13 installed at the top end of the oxidation reactor 1, the liquid distribution disk 13 comprises a disk body 1301, and the top of the disk body 1301 is in a frustum shape and is similar to the whole disk body 1301, and a plurality of V-shaped flow guide structures are arranged on the upper surface of the tray body 1301 at equal intervals, each V-shaped flow guide structure comprises a first flow guide sloping plate 1302 and a second flow guide sloping plate 1303, a V-shaped flow guide channel is formed between the first flow guide sloping plate 1302 and the second flow guide sloping plate 1303, a plurality of vent holes 1304 are formed in the tray body 1301, a plurality of flow guide bottom plates 1305 are obliquely arranged at the bottom of the tray body 1301, the flow guide bottom plates 1305 are arranged at equal intervals, flow guide grooves 1306 are formed in the flow guide bottom plates 1305, a plurality of flow guide supporting plates 1307 are arranged between the tray body 1301 and the flow guide bottom plates 1305, the bottom ends of the flow guide supporting plates 1307 are in contact with the flow guide grooves 1306, a circular cavity 1308 for the stirrer 14 to pass through is formed in the middle of the liquid distribution tray 13, a dehydration tower 2 is arranged at the top of the oxidation reactor 1, and the dehydration tower 2 is connected with the oxidation reactor 1 through a pipeline.
It should be noted that in the present embodiment, the reflux liquid at the top end of the oxidation reactor 1 drops onto the liquid distribution plate 13, and the reflux liquid is generated during the reaction process, and specifically, how to form the reflux liquid belongs to the prior art, so that it is not described in detail. Because the top of the tray body 1301 is conical, and a plurality of V-shaped flow guide structures are arranged on the upper surface of the tray body 1301 at equal intervals, the reflux liquid can flow to the inner wall of the oxidation reactor 1 along a V-shaped flow guide channel formed between the first flow guide sloping plate 1302 and the second flow guide sloping plate 1303, so that the inner wall of the oxidation reactor 1 can be effectively washed, and the inner wall of the oxidation reactor 1 is prevented from accumulating scale, in addition, part of the reflux liquid can drop on the flow guide support plate 1307 after passing through the vent holes 1304, so as to flow onto the flow guide bottom plate 1305 along the flow guide support plate 1307, and flow onto the inner wall of the oxidation reactor 1 along the flow guide groove 1306 on the flow guide bottom plate 1305, so as to further improve the washing effect, in addition, the vent holes 1304 ensure that the tail gas can pass through the liquid distribution tray 13 to be discharged out of the oxidation reactor 1, in addition, the whole liquid distribution tray 13 is made of high-density polyethylene, so that the paint is not dissolved in any organic solvent at room temperature, and is resistant to corrosion of acid, alkali and various salts; furthermore, the water-absorbing material is more suitable for being applied to the embodiment, and has small permeability to water vapor and air and low water absorption; however, the performance of the resin is reduced by thermal oxidation, so that an antioxidant, an ultraviolet absorbent and the like are required to be added into the resin to overcome the defect, and by utilizing the device, the reflux liquid can be uniformly guided onto the inner wall of the oxidation reactor 1, and the reactant on the inner wall of the oxidation reactor 1 is washed, so that the reactant is not easy to scale on the inner wall of the oxidation reactor 1.
As a specific embodiment, the agitator 14 includes an agitator 1401 vertically disposed in the oxidation reactor 1, two fixing bases 1403 are installed on the agitator 1401, a top convection spiral piece 1405 is installed on one fixing base 1403, a bottom convection spiral piece 1404 is installed on the other fixing base 1403, spiral grooves 1406 are respectively opened on the top convection spiral piece 1405 and the bottom convection spiral piece 1404, the top convection spiral piece 1405 and the bottom convection spiral piece 1404 are symmetrically disposed, a motor 1402 is installed on the top of the oxidation reactor 1, and an output end of the motor 1402 is fixed to a top end of the agitator 1401.
It should be noted that, this embodiment improves the conventional stirring plate, the special two symmetrically disposed spiral plates can improve the convection property of the gas, so as to sufficiently mix the material with the reaction gas, thereby ensuring good gas flow stirring and particle suspension, and further making the oxidation reactor 1 have high efficiency, after the gas enters from the gas inlet 103, the stirrer 14 is turned on, the motor 1402 is turned on by the master controller, the motor 1402 drives the stirring rod 1401 to rotate, thereby driving the top convection spiral plate 1405 and the bottom convection spiral plate 1404 fixed on the stirring rod to rotate, and as the material and the gas suspend, the reaction starts, while the top convection spiral plate 1405 and the bottom convection spiral plate 1404 are sufficiently stirred, the top convection spiral plate 1405 and the bottom convection spiral plate 1404 rotate to generate a convection phenomenon, so that the material and the gas between the top convection spiral plate 1405 and the bottom convection spiral plate 1404 are sufficiently mixed, thereby improving the reaction efficiency.
As a specific embodiment, a water content detector 11 is installed at the bottom end of the oxidation reactor 1, a detection cavity is arranged inside the water content detector 11, a water inlet pipe 1101 is installed on the water content detector 11, a water pump 1102 is arranged on the water inlet pipe 1101, one end of the water inlet pipe 1101 is arranged at the bottom of the oxidation reactor 1, a medicament pipe is further arranged on the water content detector 11, when the water content of acetic acid needs to be detected, the water pump 1102 is started, the water pump 1102 pumps acetic acid water solution into the water inlet pipe 1101, and then the acetic acid water solution enters the detection cavity to start detection, a main controller is arranged on the oxidation reactor 1, the main controller is electrically connected with the water content detector 11, and the main controller is used for controlling the water content detector 11, the infrared carbon dioxide analyzer 12 and the oxygen analyzer so that the monitoring is more convenient, it should be noted that the water in the oxidation reactor 1 comes from the by-products of the feed (solvent and catalyst) reaction, if no water is extracted, the water in the oxidation reactor 1 will reach about 18%, the reaction will be inhibited and a high catalyst concentration will be required, increasing the catalyst concentration will increase the "acetic acid combustion", thus increasing the consumption of acetic acid and catalyst, therefore the water content will need to be reduced, but if the water content is too low, the acetic acid combustion will also increase, and when the water content in the acetic acid is too low, the corrosion to stainless steel will be enhanced, therefore the optimum water content in the oxidation reactor 1 is 8%, but since the water content in the oxidation reactor 1 is not easily measured, the water content of the acetic acid at the bottom of the oxidation reactor 1 needs to be closely monitored, thus ensuring the water content in the oxidation reactor 1, it should be understood that the water content detector 11 is a karl fischer coulometer, the detection speed is fast, the data parallelism is good, the electric quantity of the electrolytic cell and the I (iodine) quantity have a strict quantitative relation, so the coulometry method has higher measurement precision, and is suitable for the measurement of trace and trace water.
As a specific example, the top of the oxidation reactor 1 is provided with an infrared carbon dioxide analyzer 12, the infrared carbon dioxide analyzer 12 is provided with a high pressure hose for delivering carbon dioxide, the infrared carbon dioxide analyzer 12 is electrically connected with a general controller, it is required to know that the content of carbon dioxide in the tail gas is used for measuring the 'burning' degree of acetic acid and paraxylene, the content of carbon dioxide is continuously measured for strictly representing the reaction condition and also for warning the possible internal fire, therefore, a method for rapidly measuring the content of carbon dioxide is required, the carbon dioxide has an absorption peak in the infrared region, and no obvious absorption of oxygen, nitrogen, carbon monoxide and water vapor exists under the absorption peak of a specific wavelength, so the infrared absorption method is an ideal method for measuring the carbon dioxide in the air, and commodity infrared absorption method carbon dioxide analyzer adopts the single light path, the detection mode of time double beam, reach the purpose of double light path, make detection speed fast and comparatively accurate, and be equipped with a little electromagnetic pump in the instrument, can inhale the ambient air automatically and measure, measurement process is simple, it is quick, utilize the content that this device can detect the carbon dioxide in the tail gas, thereby can be used for surveing the combustion degree of acetic acid and paraxylene, in addition, through survey carbon dioxide content in succession, can be used for strict representation reaction condition, and also be used for warning the inside conflagration that probably takes place.
As a specific example, a plurality of oxygen analyzers are arranged on the oxidation reactor 1, and the oxygen analyzers are electrically connected with a general controller, it is required to be known that the volume content of oxygen in the non-condensable gas leaving the condenser at the top of the oxidation reactor 1, including nitrogen, carbon dioxide, carbon monoxide, methyl acetate, some unreacted p-xylene, methyl bromide, and oxygen tail gas, is kept at about 3-4%, so that excessive oxygen can be ensured in the reactor to obtain qualified products, and the low oxygen content in the oxidation reactor 1 will generate excessive colored gas and trimellitic acid, so that manganese will be precipitated as manganese trimellitate, which results in an excessive manganese content, and the oxygen content exceeding 7.5% will form combustion gas, so that it is necessary for monitoring oxygen, in this example, an on-line oxygen analyzer is used as an oxygen detecting instrument, its characteristics are that detect fast, and the testing result is accurate, through the water content detector 11 that sets up, mutually supporting of inlet tube 1101 and water pump 1102 etc. can be strict detect the water content in the acetic acid to guarantee the water content in the reactor, guarantee that the high efficiency of reaction goes on.
As a specific embodiment, the crystallization device further comprises a first slurry tank 3, a centrifuge 4, a pulping tank 5, a rotary vacuum filter 6, a dryer 7, a stock bin 8, a hopper 9 and a second slurry tank 10, wherein the first slurry tank 3 is connected with the oxidation reactor 1 through a discharge pipe 101, the rotary vacuum filter 6 is connected with the oxidation reactor 1 through a connecting pipe 102, a substrate is conveyed into the first slurry tank 3 through the discharge pipe 101, the centrifuge 4, the pulping tank 5, the rotary vacuum filter 6 and the dryer 7 are connected through a conveying pipeline, one side of the second slurry tank 10 is further connected with a hydrogenation reactor, one side of the hydrogenation reactor is sequentially provided with a first crystallizer, a second crystallizer and a third crystallizer which are connected in series, the first crystallizer is connected with the hydrogenation reactor through a pipeline, the stock bin 8 is connected with the hopper 9 through an air supply system, a spiral feeder is connected between the hopper 9 and the second slurry tank 10, it should be noted that the basic process flow of the embodiment is that paraxylene, acetic acid solvent, cobalt acetate, manganese acetate catalyst and tetrabromoethane cocatalyst enter the oxidation reactor 1, air (mixed gas of air and pure oxygen) enters the bottom of the oxidation reactor 1 under the flow control, a plurality of online oxygen analyzers detect the concentration of oxygen in tail gas, the substrate at the bottom of the oxidation reactor 1 is continuously discharged into the first slurry tank 3, the pressure is reduced to normal pressure in one step, then TA is precipitated by decompression flash evaporation, the slurry is sent into the centrifuge 4, wet filter cakes separated by the centrifuge 4 enter the pulping tank 5 for repulping and then are sent into the rotary filter 6 to separate TA from mother liquor, then the mother liquor enters circulation to act as reaction solvent, the TA filter cakes enter the dryer 7 for drying to obtain CTA, reaction tail gas is conveyed into a stock bin 8, then slurry is subjected to pressure reduction crystallization step by step in a first crystallizer, a second crystallizer and a third crystallizer in sequence, and PTA is precipitated from the slurry, wherein the first slurry tank 3, the centrifuge 4, the pulping tank 5, the rotary vacuum filter 6, the dryer 7, the stock bin 8, the hopper 9, the second slurry tank 10, the hydrogenation reactor, the first crystallizer, the second crystallizer and the third crystallizer are all existing equipment in the embodiment, and how to cooperate with each other, the existing technology is adopted, so detailed description is omitted.
As a specific embodiment, it should be noted that, in order to control the reaction selectivity, several streams of materials containing acetic acid solvent are extracted from the oxidation reactor 1 in the process, enter the dehydration tower 2, the solvent containing about 95% acetic acid is obtained by removing water through rectification operation, and then return to the reaction unit, and is synchronous with the expansion of the PTA device, in order to improve the processing capacity of the solvent dehydration tower 2, a plurality of layers of tower trays 201 are installed in the dehydration tower 2, downcomers 202 are connected between the tower trays 201, the downcomers 202 incline towards the inner wall of the dehydration tower 2 from top to bottom, the widths of the downcomers 202 are reduced from top to bottom in sequence, the bottom of the downcomers 202 form a long and thin strip shape, the inner cavity of the downcomers 202 is gradually enlarged from bottom to top, a plurality of drainage fins 203 are connected to the side of the downcomers 202 at equal intervals, the cross sections of the drainage fins 203 are isosceles trapezoids, and drainage grooves 204 are arranged on the drainage fins 203, the tray 201 is provided with a plurality of triangular floating valves, rectangular composite hole fixed valves and bubbling promoters, it is to be noted that the triangular floating valves, the rectangular composite hole fixed valves and the bubbling promoters are all the prior art, the specific working principle is not described in detail, it is to be understood that most downcomers adopt vertical arched downcomers, the downcomers are adopted, uneven distribution of gas-liquid flow is easy to form on the tray 201, at the outlet of the downcomer, the liquid speed is high, the static pressure is high, gas is difficult to pass through, and is a dead zone of gas flow, at two sides of the tray 201, because the liquid flowing out of two sides of the downcomer is extremely little, a dead zone of liquid flow is formed, the effective bubbling area is greatly reduced due to the existence of the two dead zones, the gas-liquid contact time is reduced, the gas-liquid separation efficiency is damaged, the two sides of the downcomer 202 are the same as the common vertical arched downcomers and inclined downcomers, the special design makes the downcomer 202 effectively increase the length of the liquid flow path and increase the gas-liquid contact time, thereby improving the mass transfer efficiency of the column plate, the utilization of the downcomer 202 not only solves the problem of liquid flow dead zone, but also eliminates the problem of gas flow non-uniformity, in particular, because the cavity inside the downcomer 202 is gradually enlarged from bottom to top, the liquid velocity is high at the outlet of the downcomer 202, but the static pressure is reduced, so that the gas can pass through easily, because the inclined arrangement is compared with the vertical arched downcomer, the liquid can more easily flow out from both sides of the downcomer 202, a dead zone for liquid flow is not easily formed, and in addition, a part of the water flow can also more easily flow onto the downcomer 202, so that the water flow smoothly flows along the drainage grooves 204 on the drainage pieces 203, and the cliff type falling cannot occur.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. The utility model provides a p-xylene oxidation crystallization device, includes oxidation reactor (1), dehydration tower (2), first thick liquid jar (3), centrifuge (4), making beating jar (5), rotatory vacuum filter (6), desiccator (7), feed bin (8), hopper (9) and second thick liquid jar (10), be connected through the pipeline between dehydration tower (2) and oxidation reactor (1), be connected through discharge pipe (101) between first thick liquid jar (3) and oxidation reactor (1), centrifuge (4), making beating jar (5), rotatory vacuum filter (6) and desiccator (7) are all connected through the conveyer pipeline, be connected through connecting pipe (102) between rotatory vacuum filter (6) and oxidation reactor (1), second thick liquid jar (10) one side still is connected with hydrogenation ware, and hydrogenation ware one side sets gradually the first crystallizer of establishing ties each other, Second crystallizer and third crystallizer are connected through the pipeline between first crystallizer and the hydrogenation ware, oxidation reactor (1) one side is connected with inlet pipe (104) that are used for the feeding, and oxidation reactor (1) bottom is provided with integrated into one piece's air inlet (103), installs the structure of admitting air in air inlet (103), and oxidation reactor (1) bottom is connected with discharge pipe (101), its characterized in that: the oxidation reactor (1) is internally provided with a stirrer (14) and a liquid distribution disc (13) arranged at the top end of the oxidation reactor (1), the liquid distribution disc (13) comprises a disc body (1301), the top of the disc body (1301) is in a frustum shape, the upper surface of the disc body (1301) is provided with a plurality of V-shaped flow guide structures at equal intervals, each V-shaped flow guide structure comprises a first flow guide inclined plate (1302) and a second flow guide inclined plate (1303), a V-shaped flow guide channel is formed between the first flow guide inclined plate (1302) and the second flow guide inclined plate (1303), the disc body (1301) is provided with a plurality of vent holes (1304), the bottom of the disc body (1301) is obliquely provided with a plurality of flow guide bottom plates (1305), the flow guide bottom plates (1305) are arranged at equal intervals, flow guide grooves (1306) are respectively formed in the flow guide bottom plates (1305), and a plurality of flow guide support plates (1307) are arranged between the disc body (1301) and the flow guide bottom plates (1305) so that part of backflow liquid can drop onto the flow guide support plates (1307) after passing through the vent holes (1304), the bottom end of the flow guide support plate (1307) is contacted with the flow guide groove (1306), and a circular cavity (1308) for the stirrer (14) to pass through is formed in the middle of the liquid distribution disc (13);
the dehydration tower is characterized in that a plurality of layers of trays (201) are arranged in the dehydration tower (2), downcomers (202) are connected between the trays (201), the downcomers (202) incline to the inner wall of the dehydration tower (2) from top to bottom, the widths of the downcomers (202) are sequentially reduced from top to bottom, the bottom of each downcomer (202) forms a long and thin strip shape, and the inner cavity of each downcomer (202) is gradually enlarged from bottom to top.
2. The apparatus for the oxidative crystallization of paraxylene according to claim 1, wherein: agitator (14) are including vertical puddler (1401) of setting in oxidation reactor (1), install two fixing bases (1403) on puddler (1401), install top convection spiral piece (1405) on one fixing base (1403), install bottom convection spiral piece (1404) on another fixing base (1403), the helicla flute has all been seted up on top convection spiral piece (1405) and bottom convection spiral piece (1404), the symmetry sets up between top convection spiral piece (1405) and bottom convection spiral piece (1404), oxidation reactor (1) top installation motor (1402), the top of motor (1402) output and puddler (1401) is fixed mutually.
3. The apparatus for the oxidative crystallization of paraxylene according to claim 1, wherein: the water content detector (11) is installed to oxidation reactor (1) bottom, and water content detector (11) inside is provided with the detection chamber, installs inlet tube (1101) on water content detector (11), is equipped with water pump (1102) on inlet tube (1101), and oxidation reactor (1) bottom is arranged in to inlet tube (1101) one end, still is equipped with the medicament pipe on water content detector (11), is equipped with total controller on oxidation reactor (1), through electric connection between total controller and water content detector (11).
4. The apparatus for the oxidative crystallization of paraxylene according to claim 3, wherein: infrared carbon dioxide analysis appearance (12) are installed on oxidation reactor (1) top, install the high pressure hose on infrared carbon dioxide analysis appearance (12), and the high pressure hose is used for carrying carbon dioxide, passes through electric connection between infrared carbon dioxide analysis appearance (12) and the master controller.
5. The apparatus for the oxidative crystallization of paraxylene according to claim 3, wherein: a plurality of oxygen analyzers are arranged on the oxidation reactor (1), and the oxygen analyzers are electrically connected with the master controller.
6. The apparatus for the oxidative crystallization of paraxylene according to claim 1, wherein: the side edges of the downcomer (202) are connected with a plurality of drainage sheets (203) at equal intervals, the cross sections of the drainage sheets (203) are isosceles trapezoids, drainage grooves (204) are formed in the drainage sheets (203), and a plurality of triangular floating valves, rectangular composite hole fixed valves and bubbling promoters are installed on the tray (201).
7. The apparatus for the oxidative crystallization of paraxylene according to claim 1, wherein: an air supply system is connected between the stock bin (8) and the hopper (9), and a spiral feeder is connected between the hopper (9) and the second slurry tank (10).
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| US7196215B2 (en) * | 2001-06-04 | 2007-03-27 | Eastman Chemical Company | Process for the production of purified terephthalic acid |
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| US7381836B2 (en) * | 2004-09-02 | 2008-06-03 | Eastman Chemical Company | Optimized liquid-phase oxidation |
| CN207307240U (en) * | 2017-08-21 | 2018-05-04 | 成都金开生物工程有限公司 | A kind of crystallization apparatus that initial crystallization is carried out to kojic acid raw material |
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| CN2372032Y (en) * | 1998-12-01 | 2000-04-05 | 南京凯宁精馏技术有限公司 | Complex hole miniature valve high-effective column plate |
| CN101817744A (en) * | 2010-04-30 | 2010-09-01 | 中国石油天然气集团公司 | Oxidizing and crystallizing method of paraxylene |
| CN208694974U (en) * | 2018-05-10 | 2019-04-05 | 浙江科峰新材料有限公司 | It is a kind of for producing the ultrasonic wave added emulsion reactor of amido silicone oil microemulsion |
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