CN115974018A - Continuous synthesis process and device for phosphorus pentachloride - Google Patents
Continuous synthesis process and device for phosphorus pentachloride Download PDFInfo
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- CN115974018A CN115974018A CN202310115606.9A CN202310115606A CN115974018A CN 115974018 A CN115974018 A CN 115974018A CN 202310115606 A CN202310115606 A CN 202310115606A CN 115974018 A CN115974018 A CN 115974018A
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- phosphorus trichloride
- phosphorus pentachloride
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- UHZYTMXLRWXGPK-UHFFFAOYSA-N phosphorus pentachloride Chemical compound ClP(Cl)(Cl)(Cl)Cl UHZYTMXLRWXGPK-UHFFFAOYSA-N 0.000 title claims abstract description 158
- 238000000034 method Methods 0.000 title claims abstract description 47
- 230000008569 process Effects 0.000 title claims abstract description 39
- 238000003786 synthesis reaction Methods 0.000 title claims abstract description 35
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 34
- FAIAAWCVCHQXDN-UHFFFAOYSA-N phosphorus trichloride Chemical compound ClP(Cl)Cl FAIAAWCVCHQXDN-UHFFFAOYSA-N 0.000 claims abstract description 195
- 239000011552 falling film Substances 0.000 claims abstract description 137
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 61
- 239000000460 chlorine Substances 0.000 claims abstract description 61
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 61
- 239000007788 liquid Substances 0.000 claims abstract description 59
- 239000002002 slurry Substances 0.000 claims abstract description 47
- 239000007790 solid phase Substances 0.000 claims abstract description 43
- 239000013078 crystal Substances 0.000 claims abstract description 27
- 230000000382 dechlorinating effect Effects 0.000 claims abstract description 20
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims abstract description 16
- 238000000926 separation method Methods 0.000 claims abstract description 16
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 239000012071 phase Substances 0.000 claims description 85
- 238000010521 absorption reaction Methods 0.000 claims description 58
- 239000007791 liquid phase Substances 0.000 claims description 40
- 238000010992 reflux Methods 0.000 claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 18
- 238000003756 stirring Methods 0.000 claims description 14
- 238000009833 condensation Methods 0.000 claims description 10
- 230000005494 condensation Effects 0.000 claims description 10
- 230000014759 maintenance of location Effects 0.000 claims description 6
- 238000004062 sedimentation Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 21
- 230000036541 health Effects 0.000 abstract description 7
- 238000012423 maintenance Methods 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 141
- 239000000543 intermediate Substances 0.000 description 58
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 14
- 238000006298 dechlorination reaction Methods 0.000 description 11
- 239000002826 coolant Substances 0.000 description 9
- 239000007787 solid Substances 0.000 description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 description 7
- 239000001569 carbon dioxide Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000007599 discharging Methods 0.000 description 4
- 239000003507 refrigerant Substances 0.000 description 4
- 239000002912 waste gas Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000004886 process control Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 238000005660 chlorination reaction Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- CTSLXHKWHWQRSH-UHFFFAOYSA-N oxalyl chloride Chemical compound ClC(=O)C(Cl)=O CTSLXHKWHWQRSH-UHFFFAOYSA-N 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- SKDHHIUENRGTHK-UHFFFAOYSA-N 4-nitrobenzoyl chloride Chemical compound [O-][N+](=O)C1=CC=C(C(Cl)=O)C=C1 SKDHHIUENRGTHK-UHFFFAOYSA-N 0.000 description 1
- HSHGZXNAXBPPDL-HZGVNTEJSA-N 7beta-aminocephalosporanic acid Chemical compound S1CC(COC(=O)C)=C(C([O-])=O)N2C(=O)[C@@H]([NH3+])[C@@H]12 HSHGZXNAXBPPDL-HZGVNTEJSA-N 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000012320 chlorinating reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000012024 dehydrating agents Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- -1 lithium hexafluorophosphate Chemical compound 0.000 description 1
- 239000011268 mixed slurry Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000012450 pharmaceutical intermediate Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A continuous synthesis process of phosphorus pentachloride comprises the following steps: reacting phosphorus trichloride with chlorine in a falling film reactor to obtain mixture slurry of the phosphorus trichloride and phosphorus pentachloride, settling in a settler, continuously feeding the obtained crystal slurry into a solid-liquid separator through a slurry conveying device for solid-liquid separation, feeding the obtained solid-phase phosphorus pentachloride into a primary continuous devolatilization device for removing the phosphorus trichloride, feeding the obtained phosphorus pentachloride product into a secondary continuous devolatilization device for reacting with excessive chlorine, and further removing the phosphorus trichloride attached to the surface of a phosphorus pentachloride crystal to obtain refined phosphorus pentachloride; and then chlorine gas attached to the surface of the crystal is removed by a continuous dechlorinating device to obtain a phosphorus pentachloride product. The process can be used for continuously producing the phosphorus pentachloride, has high efficiency and stable and controllable product quality, and can solve the problems of poor process stability, high safety risk in shutdown maintenance and production processes, unsatisfactory occupational health environment, high environmental protection tail gas treatment and operation cost and the like in the conventional phosphorus pentachloride production process.
Description
Technical Field
The invention relates to the technical field of phosphorus pentachloride synthesis, in particular to a continuous phosphorus pentachloride synthesis process and a device.
Background
Phosphorus pentachloride is one of phosphorus chlorides which are widely applied, is widely used as a chlorinating agent, a catalyst, a dehydrating agent and the like in organic synthesis, has the characteristics of quick reaction, high product yield and the like, and is used for synthesizing pharmaceutical intermediates such as 7-ACA, p-nitrobenzoyl chloride, oxalyl chloride and the like. In the field of inorganic chemistry, phosphorus pentachloride is widely used for the production of lithium hexafluorophosphate and the like as an electrolyte of a lithium battery.
At present, the mainstream production process of phosphorus pentachloride is an intermittent method, the synthesis method of phosphorus pentachloride takes phosphorus trichloride and chlorine as raw materials to react, a gas-liquid reaction method of reacting chlorine and liquid phosphorus trichloride is generally adopted, liquid phosphorus trichloride is added into a closed reaction kettle, and then chlorine is introduced to react to obtain the phosphorus pentachloride. However, the phosphorus pentachloride product is solid, and the system is more and more difficult to stir or even difficult to stir along with the increase of the conversion rate of the phosphorus trichloride. In order to ensure that the phosphorus trichloride reacts completely as much as possible, excess chlorine is generally introduced for chlorination, and dry carbon dioxide gas is introduced after the reaction is finished to discharge residual chlorine. However, even in this case, the content of residual phosphorus trichloride in the product is still high, generally 0.05% or more and 0.1% or more, and chlorine gas is not completely discharged, resulting in uneven product particles, strong hygroscopicity, poor flowability, and the like.
In conclusion, the existing process for producing phosphorus pentachloride has the defects of high content of residual phosphorus trichloride, uneven granularity, poor fluidity and the like in a product, particularly in an intermittent reaction system, the discharge of a reactor is easy to block due to the existence of solids, the safety risk caused by manual cleaning is avoided, and meanwhile, the production efficiency of producing phosphorus pentachloride by intermittent reaction is low, and the occupational health cannot be guaranteed.
Patent CN201520190018.2 and patent CN212222426U both disclose phosphorus pentachloride production devices, and liquid phosphorus trichloride is added with chlorine gas in a chlorination kettle, and the phosphorus pentachloride is prepared after mixing, reaction, drying and replacement, but the method and the device of the technical scheme still have more or less problems in the analysis. Patent CN202110261875.7 discloses a method and a device for continuously preparing high-purity phosphorus pentachloride, and mixed gas consisting of chlorine and inert gas is prepared; atomizing liquid phosphorus trichloride, and then carrying out mixed reaction with the mixed gas to obtain solid high-purity phosphorus pentachloride; however, the device used in the method has the problems of large equipment occupation area, unsatisfactory stability of process control, high occupational health risk, high tail gas treatment cost, difficult parking inspection and maintenance of the device and the like.
Therefore, the stability of the device, the safety of the production process and the high efficiency and continuity of the process of the traditional phosphorus pentachloride production process are important guarantees of the phosphorus pentachloride production process, the intermittent process control is guaranteed, but the production efficiency is low, the spraying process production efficiency is high, but the process control stability control requirement is high, and the two traditional methods have the problem of high safety risk.
Disclosure of Invention
In view of this, the present invention provides a continuous synthesis process and a device for phosphorus pentachloride, which can significantly improve the production efficiency of phosphorus pentachloride, improve the reliability of device control, reduce the risk of device safety production, and reduce the occupational health risk of the phosphorus pentachloride production process.
The invention provides a continuous synthesis process of phosphorus pentachloride, which comprises the following steps:
a) Reacting phosphorus trichloride and chlorine in a falling-film reactor to obtain a mixture slurry of the phosphorus trichloride and phosphorus pentachloride, condensing the generated gas phase, and refluxing to the falling-film reactor for reuse;
b) Settling the slurry of the mixture of phosphorus trichloride and phosphorus pentachloride obtained in the step a) in a settler, continuously feeding the obtained crystal slurry into a solid-liquid separator through a slurry conveying device for solid-liquid separation, respectively obtaining liquid-phase phosphorus trichloride to flow back to a falling-film reactor, gas-phase phosphorus trichloride to flow back to the falling-film reactor for reuse after condensation, and solid-phase phosphorus pentachloride; condensing the gas phase obtained by settling, and then refluxing the condensed gas phase to the falling film reactor for reuse;
c) Allowing the solid-phase phosphorus pentachloride obtained in the step b) to enter a first-stage continuous devolatilizer to remove phosphorus trichloride, condensing the obtained gas phase, refluxing the condensed gas phase to a falling film reactor for reuse, allowing the obtained phosphorus pentachloride product to enter a second-stage continuous devolatilizer to react with excessive chlorine, and further removing phosphorus trichloride attached to the surface of a phosphorus pentachloride crystal to obtain refined phosphorus pentachloride; unreacted chlorine is absorbed by a falling film absorption tower, a small amount of phosphorus pentachloride generated flows back to a phosphorus trichloride intermediate tank along with phosphorus trichloride, and the phosphorus trichloride is conveyed to the falling film reactor by a phosphorus trichloride circulating pump for reuse;
d) Removing chlorine attached to the surface of the crystal of the refined phosphorus pentachloride obtained in the step c) by a continuous dechlorinating device to obtain a phosphorus pentachloride product;
e) Condensing the tail gas generated after condensation in the steps a), b) and c) by a tail gas condenser to recover phosphorus trichloride, and absorbing the phosphorus trichloride by a tail gas absorption tower.
Preferably, the feeding molar ratio of the phosphorus trichloride to the chlorine in the step a) is 1: (0.4-4.5).
Preferably, the temperature of the reaction in the step a) is 40-75 ℃, and the pressure is 0.1-20 KPa.
Preferably, the temperature of the sedimentation in the step b) is 40-75 ℃, the pressure is 0.1-20 KPa, and the stirring speed is 3-60 rpm.
Preferably, the flow rate of the solid-liquid separation in the step b) is 3L/h to 15L/h, the temperature is 40 ℃ to 75 ℃, and the pressure is 0.1KPa to 1KPa.
Preferably, the temperature for removing the phosphorus trichloride in the first-stage continuous devolatilization device in the step c) is 75-90 ℃, the pressure is 0.4-20 KPa, and the retention time is 5-10 min.
Preferably, the temperature of the reaction between the gas entering the secondary continuous devolatilization device and the excessive chlorine in the step c) is 40-75 ℃, the pressure is-5 KPa-10 KPa, and the retention time is 1-5 min.
Preferably, the temperature absorbed by the falling film absorption tower in the step c) is 5-25 ℃, and the pressure is-5 KPa to-0.1 KPa.
Preferably, the temperature for removing the chlorine attached to the surface of the crystal by the continuous dechlorinating device in the step d) is 30-55 ℃, and the pressure is 1-8 KPa.
The invention also provides a device for continuously synthesizing phosphorus pentachloride, which comprises:
a falling film reactor; the falling film reactor is provided with a chlorine inlet and a phosphorus trichloride inlet; the phosphorus trichloride inlet is also connected with an intermediate condenser;
the feed inlet is connected with the discharge port of the falling film reactor;
the slurry conveying device is connected with the feed inlet and the discharge outlet of the settler;
the feed inlet is connected with the discharge port of the slurry conveying device; the liquid phase outlet of the solid-liquid separator is connected with the phosphorus trichloride inlet of the falling film reactor, and the gas phase outlet is connected with the phosphorus trichloride inlet of the falling film reactor through an intermediate condenser;
a first-stage continuous devolatilization device with a feed inlet connected with a solid phase outlet of the solid-liquid separator; the gas phase outlet of the first-stage continuous devolatilization device is connected with the phosphorus trichloride inlet of the falling film reactor through an intermediate condenser;
a second-stage continuous devolatilization device with a feed port connected with a solid phase outlet of the first-stage continuous devolatilization device; the secondary continuous devolatilization device is provided with a chlorine inlet, a chlorine outlet and a phosphorus pentachloride outlet; the chlorine outlet is also connected with a falling film absorption tower; the phosphorus pentachloride outlet is sequentially connected with an upper rotary valve, a continuous dechlorinating device and a lower rotary valve;
a phosphorus trichloride intermediate tank with a feed inlet connected with a liquid phase outlet of the falling film absorption tower; the phosphorus trichloride intermediate tank is connected with a phosphorus trichloride inlet of the falling film reactor through a phosphorus trichloride circulating pump;
the tail gas condenser is connected with a tail gas outlet of the middle condenser through a gas inlet; and a liquid phase outlet of the tail gas condenser is connected with a feed inlet of the phosphorus trichloride intermediate tank, and a gas phase outlet of the tail gas condenser is also connected with a tail gas absorption tower.
The invention provides a continuous synthesis process and a device of phosphorus pentachloride; the process comprises the following steps: a) Reacting phosphorus trichloride and chlorine in a falling-film reactor to obtain a mixture slurry of the phosphorus trichloride and phosphorus pentachloride, condensing the generated gas phase, and refluxing to the falling-film reactor for reuse; b) Settling the slurry of the mixture of phosphorus trichloride and phosphorus pentachloride obtained in the step a) in a settler, continuously feeding the obtained crystal slurry into a solid-liquid separator through a slurry conveying device for solid-liquid separation, respectively obtaining liquid-phase phosphorus trichloride to flow back to a falling-film reactor, gas-phase phosphorus trichloride to flow back to the falling-film reactor for reuse after condensation, and solid-phase phosphorus pentachloride; condensing the gas phase obtained by settling, and then refluxing the condensed gas phase to the falling film reactor for reuse; c) Allowing the solid-phase phosphorus pentachloride obtained in the step b) to enter a first-stage continuous devolatilizer to remove phosphorus trichloride, condensing the obtained gas phase, refluxing the condensed gas phase to a falling film reactor for reuse, allowing the obtained phosphorus pentachloride product to enter a second-stage continuous devolatilizer to react with excessive chlorine, and further removing phosphorus trichloride attached to the surface of a phosphorus pentachloride crystal to obtain refined phosphorus pentachloride; unreacted chlorine is absorbed by a falling film absorption tower, a small amount of phosphorus pentachloride generated flows back to a phosphorus trichloride intermediate tank along with phosphorus trichloride, and the phosphorus trichloride is conveyed to the falling film reactor by a phosphorus trichloride circulating pump for reuse; d) Removing chlorine attached to the surface of the crystal of the refined phosphorus pentachloride obtained in the step c) by a continuous dechlorinating device to obtain a phosphorus pentachloride product; e) Condensing the tail gas generated after condensation in the steps a), b) and c) by a tail gas condenser to recover phosphorus trichloride, and absorbing the phosphorus trichloride by a tail gas absorption tower. Compared with the prior art, the continuous synthesis process and the device for phosphorus pentachloride provided by the invention realize better overall interaction through specific process steps under specific structures and continuous relations, can realize continuous production, have high efficiency and stable and controllable product quality, and can solve the problems of poor process stability, high safety risk in shutdown maintenance and production processes, unsatisfactory occupational health environment, high environment-friendly tail gas treatment and operation cost and the like in the conventional phosphorus pentachloride production process.
Drawings
FIG. 1 is a flow chart of a continuous synthesis process of phosphorus pentachloride provided by an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a phosphorus pentachloride continuous synthesis apparatus provided in the embodiment of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood 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.
The invention provides a continuous synthesis process of phosphorus pentachloride, which comprises the following steps:
a) Reacting phosphorus trichloride with chlorine in a falling film reactor to obtain a mixture slurry of the phosphorus trichloride and phosphorus pentachloride, and condensing the generated gas phase and then refluxing the condensed gas to the falling film reactor for reuse;
b) Settling the slurry of the mixture of phosphorus trichloride and phosphorus pentachloride obtained in the step a) in a settler, continuously feeding the obtained crystal slurry into a solid-liquid separator through a slurry conveying device for solid-liquid separation, respectively obtaining liquid-phase phosphorus trichloride to flow back to a falling-film reactor, gas-phase phosphorus trichloride to flow back to the falling-film reactor for reuse after condensation, and solid-phase phosphorus pentachloride; condensing the gas phase obtained by settling, and then refluxing the condensed gas phase to the falling film reactor for reuse;
c) Allowing the solid-phase phosphorus pentachloride obtained in the step b) to enter a primary continuous devolatilization device to remove phosphorus trichloride, condensing the obtained gas phase, refluxing the condensed gas phase to a falling film reactor for reuse, allowing the obtained phosphorus pentachloride product to enter a secondary continuous devolatilization device to react with excessive chlorine, and further removing phosphorus trichloride attached to the surface of a phosphorus pentachloride crystal to obtain refined phosphorus pentachloride; unreacted chlorine is absorbed by a falling film absorption tower, a small amount of phosphorus pentachloride generated flows back to a phosphorus trichloride intermediate tank along with phosphorus trichloride, and the phosphorus trichloride is conveyed to the falling film reactor by a phosphorus trichloride circulating pump for reuse;
d) Removing chlorine attached to the surface of the crystal of the refined phosphorus pentachloride obtained in the step c) by a continuous dechlorinating device to obtain a phosphorus pentachloride product;
e) Condensing the tail gas generated after condensation in the steps a), b) and c) by a tail gas condenser to recover phosphorus trichloride, and absorbing the phosphorus trichloride by a tail gas absorption tower.
The invention firstly reacts phosphorus trichloride and chlorine in a falling film reactor to obtain the mixture slurry of phosphorus trichloride and phosphorus pentachloride, and the generated gas phase is condensed and then flows back to the falling film reactor for reuse.
In the present invention, the phosphorus trichloride and chlorine are commercially available from sources well known to those skilled in the art, and the present invention is not particularly limited thereto.
In the present invention, the feed molar ratio of phosphorus trichloride to chlorine is preferably 1: (0.4-4.5); in certain embodiments of the invention, the liquid phosphorus trichloride to chlorine mole ratio is 1:2.2 to 4.5, and in certain embodiments of the invention, the molar ratio of liquid phosphorus trichloride to chlorine is 1:0.4 to 2.2.
In the present invention, the reaction temperature is preferably 40 to 75 ℃ and the pressure is preferably 0.1 to 20KPa.
In the invention, two phosphorus trichloride liquid inlets and a chlorine gas feed inlet are arranged at the upper part of the falling film reactor, and the heat transfer area is preferably 120m 2 The coolant is phase-change coolant; the cooling medium of the falling film reactor is water, and the temperature of the cooling water is 25-60 ℃.
In the present invention, the generated gas phase is condensed preferably by using an intermediate condenser well known to those skilled in the art.
Then, the obtained mixture slurry of phosphorus trichloride and phosphorus pentachloride is settled and primarily separated in a settler, the obtained crystal slurry (lower layer) continuously enters a solid-liquid separator through a slurry conveying device for solid-liquid separation, and liquid-phase phosphorus trichloride is respectively obtained to flow back to the falling-film reactor, a gas phase is condensed and then flows back to the falling-film reactor for reuse, and solid-phase phosphorus pentachloride is obtained; and condensing the gas phase obtained by settling, and then refluxing the condensed gas phase to the falling film reactor for reuse.
In some embodiments of the present invention, the phosphorus trichloride and the phosphorus pentachloride are settled and separated in a settler, and the solid-to-liquid ratio of the lower layer slurry of the phosphorus trichloride and the phosphorus pentachloride is controlled by stirring in the settler, and in some embodiments of the present invention, the content of the phosphorus pentachloride in the lower part of the settler is preferably 18% to 25%.
In the present invention, the temperature of the sedimentation is preferably 40 to 75 ℃, the pressure is preferably 0.1 to 20KPa, and the stirring speed is preferably 3 to 60rpm, more preferably 20 to 50rpm.
In the invention, the flow rate of the solid-liquid separation is preferably 3L/h to 15L/h, the temperature is preferably 40 ℃ to 75 ℃, and the pressure is preferably 0.1KPa to 1KPa.
In the present invention, the gas phase resulting from said settling is condensed preferably using an intermediate condenser well known to those skilled in the art.
Then, the obtained solid-phase phosphorus pentachloride enters a first-stage continuous devolatilization device to remove phosphorus trichloride, the obtained gas phase is condensed and then flows back to a falling film reactor to be reused, the obtained phosphorus pentachloride product enters a second-stage continuous devolatilization device to react with excessive chlorine, the phosphorus trichloride attached to the surface of a phosphorus pentachloride crystal is further removed, and the refined phosphorus pentachloride is obtained; unreacted chlorine is absorbed by the falling film absorption tower, and a small amount of phosphorus pentachloride generated flows back to the phosphorus trichloride intermediate tank along with the phosphorus trichloride and is conveyed to the falling film reactor by a phosphorus trichloride circulating pump for reuse.
In the invention, the solid-phase phosphorus pentachloride preferably contains about 5 to 19 percent of phosphorus trichloride, and the excessive phosphorus trichloride can be removed in a primary continuous devolatilization device; the first-stage continuous devolatilization device is preferably a horizontal reactor with double stirring, the stirring speed is preferably 80 rpm-140 rpm, the upper part of the first-stage continuous devolatilization device is provided with a material inlet, a gas phase outlet and a solid phase material outlet, the first-stage continuous devolatilization device is heated by a jacket, and a heat source is heated by steam or electricity, namely the heating mode of the first-stage continuous devolatilization device is preferably steam heating, the steam pressure is 0.02 MPa-0.4 MPa, or the first-stage continuous devolatilization device is electrically heated.
In the invention, the temperature for removing the phosphorus trichloride in the first-stage continuous devolatilization device is preferably 75-90 ℃, the pressure is preferably 0.4-20 KPa, and the retention time is preferably 5-10 min.
In the present invention, the resulting vapor phase is condensed preferably using an intermediate condenser well known to those skilled in the art.
In the invention, the second-stage continuous devolatilization device is preferably a horizontal reactor with double stirring, the stirring speed is preferably 60 rpm-140 rpm, the upper part of the second-stage continuous devolatilization device is provided with a first-stage continuous devolatilization device generation material inlet, a gas phase outlet and a solid phase material outlet, a jacket is used for cooling, and a coolant is a phase change type coolant; the temperature of the reaction between the gas entering the secondary continuous devolatilization device and the excessive chlorine is preferably 40-75 ℃, the pressure is preferably-5 KPa-10 KPa, and the retention time is preferably 1-5 min.
In the invention, the temperature absorbed by the falling film absorption tower is preferably 5-25 ℃, and the pressure is preferably-5 KPa to-0.1 Kpa; the circulating amount of the phosphorus trichloride in the falling film absorption tower is preferably 100-200L/h, and the cooling medium of the absorption tower is preferably low-temperature water or chilled water.
In the invention, the phosphorus trichloride intermediate tank is a conventional carbon steel tank, preferably provided with three feeding holes, and the lower part of the phosphorus trichloride intermediate tank is provided with a discharging hole; the phosphorus trichloride circulating pump can adopt a magnetic pump or a shield pump, and the lift is 20-60 m.
Finally, the chlorine gas attached to the surface of the crystal of the obtained refined phosphorus pentachloride is removed by a continuous dechlorinating device, and a phosphorus pentachloride product is obtained.
In the invention, the temperature of the chlorine gas removed from the crystal surface by the continuous dechlorinating device is preferably 30-55 ℃, and the pressure is preferably 1-8 KPa; the replacement gas of the continuous dechlorination device is preferably carbon dioxide or nitrogen, and is more preferably carbon dioxide.
Meanwhile, tail gas generated after condensation in the steps is condensed by a tail gas condenser to recover phosphorus trichloride, and then the phosphorus trichloride is absorbed by a tail gas absorption tower.
In the invention, the phosphorus trichloride tail gas generated by the settler is passed through an intermediate condenser (preferably a conventional tubular condenser, and the design area is preferably 30 m) 2 ～70m 2 The coolant is phase-change coolant) is condensed, the condensing temperature is preferably 6-20 ℃, the pressure is preferably normal pressure, and the phosphorus trichloride flows back to the falling film reactor for reuse; condensing the phosphorus trichloride tail gas generated by the falling film reactor through an intermediate condenser, wherein the condensing temperature is preferably 6-20 ℃, the pressure is preferably normal pressure, the phosphorus trichloride flows back to the falling film reactor for reuse, and the refrigerant is preferably low-temperature water at the temperature of 5-12 ℃; condensing the tail gas of phosphorus trichloride produced in the first-stage continuous devolatilization device by an intermediate condenser, wherein the condensing temperature is preferably 6-20 ℃, the pressure is preferably normal pressure, the phosphorus trichloride flows back to the falling film reactor for reuse, and the refrigerant is preferably low-temperature water of 5-12 ℃; and tail gas of the intermediate condenser and the falling film absorption tower is condensed by a tail gas condenser, the condensing temperature is preferably-3 ℃ to-18 ℃, the pressure is preferably normal pressure, phosphorus trichloride is recycled and refluxed to a phosphorus trichloride intermediate tank for reuse, and a refrigerant is preferably refrigerating fluid at-5 ℃ to-20 ℃.
The invention also provides a continuous synthesis device of phosphorus pentachloride, which comprises:
a falling film reactor; the falling film reactor is provided with a chlorine inlet and a phosphorus trichloride inlet; the phosphorus trichloride inlet is also connected with an intermediate condenser;
the feed inlet is connected with the discharge port of the falling film reactor;
the slurry conveying device is connected with the feed inlet and the discharge outlet of the settler;
the feed inlet is connected with the discharge port of the slurry conveying device; the liquid phase outlet of the solid-liquid separator is connected with the phosphorus trichloride inlet of the falling film reactor, and the gas phase outlet is connected with the phosphorus trichloride inlet of the falling film reactor through an intermediate condenser;
a first-stage continuous devolatilization device with a feed inlet connected with a solid phase outlet of the solid-liquid separator; the gas phase outlet of the first-stage continuous devolatilization device is connected with the phosphorus trichloride inlet of the falling film reactor through an intermediate condenser;
a second-stage continuous devolatilization device with a feed port connected with a solid phase outlet of the first-stage continuous devolatilization device; the secondary continuous devolatilization device is provided with a chlorine inlet, a chlorine outlet and a phosphorus pentachloride outlet; the chlorine outlet is also connected with a falling film absorption tower; the phosphorus pentachloride outlet is sequentially connected with an upper rotary valve, a continuous dechlorinating device and a lower rotary valve;
a feed port is connected with a liquid phase outlet of the falling film absorption tower; the phosphorus trichloride intermediate tank is connected with a phosphorus trichloride inlet of the falling film reactor through a phosphorus trichloride circulating pump;
the tail gas condenser is connected with a tail gas outlet of the middle condenser through a gas inlet; and a liquid phase outlet of the tail gas condenser is connected with a feed inlet of the phosphorus trichloride intermediate tank, and a gas phase outlet of the tail gas condenser is also connected with a tail gas absorption tower.
In the invention, the continuous synthesis process and the device of the phosphorus pentachloride comprise:
the device comprises a falling film reactor, a settler connected with a liquid phase outlet of the falling film reactor, an intermediate condenser connected with a liquid phase inlet of the falling film reactor, a solid-liquid separator connected with a liquid phase inlet of the falling film reactor, a phosphorus trichloride intermediate tank connected with a liquid phase inlet of the falling film reactor, a slurry conveying device connected with a liquid phase outlet of the settler, an intermediate condenser connected with a gas phase outlet of the settler, a slurry conveying device connected with a liquid phase inlet of the solid-liquid separator, a primary continuous devolatilization device connected with a solid phase outlet of the solid-liquid separator, an intermediate condenser connected with a gas phase outlet of the primary continuous devolatilization device, a secondary continuous devolatilization device connected with a solid phase outlet of the primary continuous devolatilization device, a falling film absorption tower connected with a gas phase outlet of the secondary continuous devolatilization device, a continuous dechlorination device connected with a solid phase outlet of the secondary continuous devolatilization device, an intermediate condenser connected with a gas phase outlet of the falling film absorption tower, a phosphorus trichloride intermediate tank connected with a liquid phase inlet of the falling film absorption tower, an intermediate condenser connected with a gas phase inlet of the tail gas phase condenser and a tail gas phase outlet of the tail gas absorption tower.
In the invention, the falling film reactor is provided with a phosphorus trichloride feeding distributor, a chlorine gas inlet, a chlorine gas distributor, a cooling jacket, a coolant inlet, a cooling jacket, a phosphorus trichloride reflux port and a phosphorus trichloride discharge port; the phosphorus trichloride feeding distributor is sequentially connected with a phosphorus trichloride circulating pump and a phosphorus trichloride intermediate tank; the phosphorus trichloride reflux port is connected with a reflux intermediate condenser; and a discharge port arranged on the falling film reactor is connected with a settler.
In the invention, the settler is provided with a feed inlet, a discharge outlet, a stirrer and a gas phase outlet; a feed inlet arranged on the settler is connected with the falling film reactor; the discharge hole arranged on the settler is connected with a slurry discharge device; and a gas phase outlet arranged on the settler is connected with an intermediate condenser.
In the invention, the solid-liquid separator is provided with a liquid phase inlet and a solid phase outlet; and a liquid phase inlet arranged on the solid-liquid separator is connected with the first-stage continuous devolatilizer.
In the invention, the first-stage continuous devolatilization gas is provided with a solid-phase feed inlet, a gas-phase outlet, a solid-phase outlet, a cooling jacket and a cold and hot medium inlet and outlet; a solid feed inlet arranged on the first-stage continuous devolatilizer is connected with the falling film reactor; a gas phase outlet arranged on the first-stage continuous devolatilization device is connected with a reflux intermediate condenser; and a solid phase outlet arranged on the first-stage continuous devolatilization device is connected with the second-stage continuous devolatilization device.
In the invention, the secondary continuous devolatilization device is provided with a feed inlet, a gas phase outlet, a solid phase outlet and a chlorine inlet; the feed inlet arranged on the secondary continuous devolatilization device is connected with the primary continuous devolatilization device; a gas phase outlet arranged on the secondary continuous devolatilization device is connected with an intermediate condenser; and a solid phase outlet arranged on the secondary continuous devolatilization device is connected with an upper rotary valve.
In the invention, the dechlorination device is provided with a feed inlet, a solid phase discharge outlet, a carbon dioxide gas inlet, a carbon dioxide gas outlet and other waste gas outlets; a feed port arranged on the dechlorinating device is connected with an upper rotary valve; a solid phase discharge hole arranged on the dechlorinating device is connected with the lower rotary valve; and the outlets of waste gas bodies such as carbon dioxide and the like arranged on the dechlorinating device are connected with the tail gas absorption tower.
In the invention, the falling film absorption tower is provided with a phase inlet, a gas phase outlet, a liquid phase inlet, a liquid phase outlet and a refrigerant inlet and outlet; a gas phase inlet arranged on the falling film absorption tower is connected with a secondary continuous devolatilization device; a gas phase outlet arranged on the falling film absorption tower is sequentially connected with a tail gas fan and a tail gas condenser; a liquid phase inlet arranged on the falling film absorption tower is sequentially connected with a phosphorus trichloride circulating pump and a phosphorus trichloride intermediate tank; and a liquid phase outlet arranged on the falling film absorption tower is connected with the phosphorus trichloride intermediate tank.
In the invention, a gas distributor and a liquid distributor are arranged in a cylinder body of the falling film reactor.
In the invention, parallel main shafts are arranged in the cylinder body of the primary continuous devolatilization device, and the main shafts are driven by a main motor to drive a main shaft speed reducer; the main shaft is provided with a composite gas stirring structure with combined blades, and combined stirring is suitable for dispersing slurry materials; a cooling jacket is arranged around the cylinder body, and a cooling and heating medium inlet and outlet are arranged on the jacket; the cylinder body is provided with 1-4 gas phase outlets and one feed inlet.
In the invention, parallel main shafts are arranged in the cylinder body of the secondary continuous devolatilization device, and the main shafts are driven by a main motor to drive a main shaft speed reducer; the main shaft is provided with a composite stirring structure of combined blades; a heating jacket is arranged around the cylinder body, and a heating carrier agent inlet and outlet are arranged on the jacket; the cylinder body is provided with 1-4 gas phase outlets, one feed inlet and one solid phase discharge outlet.
In the invention, an upper rotary valve is arranged on the dechlorination device, a lower rotary valve is arranged at an outlet, 5-10 groups of baffle plates are arranged in a cylinder body of the dechlorination device, and the baffle plates form an included angle of 45-60 degrees with the horizontal line.
The invention provides a continuous synthesis device of phosphorus pentachloride, which comprises: a phosphorus trichloride intermediate tank; the lower outlet of the phosphorus trichloride intermediate tank is connected with the inlet of a phosphorus trichloride circulating pump; the outlet of the phosphorus trichloride circulating pump is respectively connected with the liquid phase inlet of the falling film absorption tower and the liquid phase inlet of the falling film reactor, the falling film reactor is provided with a chlorine inlet, and the liquid phase inlet of the falling film reactor is respectively connected with the liquid phase outlets of the solid-liquid separator and the intermediate condensers 1 and 2; the solid phase outlet of the solid-liquid separator is connected with the solid phase inlet of the first-stage continuous devolatilization device through a rotary valve; the outlet of the falling film reactor is connected with a settler, the lower outlet of the settler is connected with the inlet of a slurry conveying device, and the outlet of the slurry conveying device is connected with the inlet of a solid-liquid separator; the solid phase outlet of the first-stage continuous devolatilization device is connected with the inlet of the downstream second-stage continuous devolatilization device, the gas phase outlet of the second-stage continuous devolatilization device is connected with the gas phase inlet of the falling film absorption tower, and the gas phase outlet of the falling film absorption tower is connected with the inlet of the tail gas fan; the solid phase outlet of the secondary continuous devolatilization device is connected with the inlet of the continuous dechlorination device through an upper rotary valve; the gas phase outlets of the falling film reactor, the first-stage continuous devolatilizer and the settler are connected with the gas phase inlets of the intermediate condensers 1 and 2; the gas phase outlets of the intermediate condensers 1 and 2, the outlet of the tail gas fan, the dechlorination device and the gas phase inlet of the tail gas condenser are connected; and a gas phase outlet of the tail gas condenser is connected with the tail gas absorption tower. The continuous synthesis device for phosphorus pentachloride provided by the invention can improve the production efficiency of phosphorus pentachloride, improve the control reliability of the device, reduce the risk of safe production of the device and reduce the occupational health risk of the production process of phosphorus pentachloride.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a phosphorus pentachloride continuous synthesis apparatus provided in the embodiment of the present invention; the device comprises a slurry conveying device, (1) a settler, (3) a falling film reactor, (4) a solid-liquid separator, (5) an intermediate condenser (1), (6) an intermediate condenser (2), (7) a first-stage continuous devolatilization device, (8) a tail gas fan, (9) a second-stage continuous devolatilization device, (10) a continuous dechlorination device, (11) a phosphorus trichloride circulating pump, (12) a phosphorus trichloride intermediate tank, (13) a falling film absorption tower, (14) a tail gas condenser, (15) a tail gas absorption tower, (16) an upper rotary valve, (17) a lower rotary valve, and (18) a solid-liquid separation discharging rotary valve.
The main connection relationship of the device is as follows: the device is provided with a phosphorus trichloride middle tank (12), a lower outlet of the phosphorus trichloride middle tank (12) is connected with an inlet of a phosphorus trichloride circulating pump (11), an outlet of the phosphorus trichloride circulating pump (11) is respectively connected with a liquid phase inlet of a falling film absorption tower (13) and a liquid phase inlet of a falling film reactor (3), the falling film reactor (3) is provided with a chlorine inlet, the liquid phase inlet of the falling film reactor (3) is respectively connected with liquid phase outlets of a solid-liquid separator (4) and middle condensers 1 and 2, and a solid phase outlet of the solid-liquid separator (4) is connected with a solid phase inlet of a primary continuous devolatilization device (7) through a solid-liquid separation discharge rotary valve (18); the outlet of the falling film reactor (3) is connected with the settler (2), the lower outlet of the settler (2) is connected with the inlet of the slurry conveying device (1), and the outlet of the slurry conveying device (1) is connected with the inlet of the solid-liquid separator (4); a solid phase outlet of the first-stage continuous devolatilization device (7) is connected with an inlet of a downstream second-stage continuous devolatilization device (9), a gas phase outlet of the second-stage continuous devolatilization device (9) is connected with a gas phase inlet of a falling film absorption tower (13), and a gas phase outlet of the falling film absorption tower (13) is connected with an inlet of a tail gas fan; the solid phase outlet of the secondary continuous devolatilization device (9) is connected with the inlet of the continuous dechlorination device (10) through an upper rotary valve (16), and the outlet of the continuous dechlorination device (10) is unpacked through a lower rotary valve; the falling film reactor (3), the first-stage continuous devolatilization device (7) and the settler (2) are connected with the gas phase outlets of the intermediate condensers (5) and (6), the outlet of the tail gas fan (8), the dechlorination device (10) are connected with the gas phase inlet of the tail gas condenser (14), and the gas phase outlet of the condenser (14) is connected with the tail gas absorption tower (15).
The main working process of the device is as follows: phosphorus trichloride and chlorine gas continuously enter a falling film reactor (3) for reaction, a mixture automatically flows into a settler (2), phosphorus pentachloride crystals are settled in the settler (2), the phosphorus pentachloride crystals are conveyed into a solid-liquid separator (4) by a slurry conveying device (1) for solid-liquid separation, phosphorus trichloride liquid flows back to the falling film reactor (3), solid phosphorus pentachloride enters a first-stage continuous devolatilizer (7) through a solid-liquid separation discharging rotary valve (18) to remove phosphorus trichloride attached to the surface of the phosphorus pentachloride, the first-stage continuous devolatilizer (7) discharges to a second-stage continuous devolatilizer (9) to further remove the phosphorus trichloride in the phosphorus pentachloride, the second-stage continuous dechlorinatier (9) discharges to a continuous dechlorinating device (10) through an upper rotary valve (16) to remove chlorine attached to the surface of the phosphorus pentachloride, and the chlorine gas is discharged through a lower rotary valve (17) to obtain a qualified phosphorus pentachloride product.
The invention provides a continuous synthesis process and a device of phosphorus pentachloride; the process comprises the following steps: a) Reacting phosphorus trichloride and chlorine in a falling-film reactor to obtain a mixture slurry of the phosphorus trichloride and phosphorus pentachloride, condensing the generated gas phase, and refluxing to the falling-film reactor for reuse; b) Settling the mixture slurry of phosphorus trichloride and phosphorus pentachloride obtained in the step a) in a settler, continuously feeding the obtained crystal slurry into a solid-liquid separator through a slurry conveying device for solid-liquid separation, and respectively obtaining liquid-phase phosphorus trichloride which flows back to the falling-film reactor, gas-phase phosphorus trichloride which flows back to the falling-film reactor for reuse after condensation, and solid-phase phosphorus pentachloride; condensing the gas phase obtained by settling, and then refluxing the condensed gas phase to the falling film reactor for reuse; c) Allowing the solid-phase phosphorus pentachloride obtained in the step b) to enter a first-stage continuous devolatilizer to remove phosphorus trichloride, condensing the obtained gas phase, refluxing the condensed gas phase to a falling film reactor for reuse, allowing the obtained phosphorus pentachloride product to enter a second-stage continuous devolatilizer to react with excessive chlorine, and further removing phosphorus trichloride attached to the surface of a phosphorus pentachloride crystal to obtain refined phosphorus pentachloride; unreacted chlorine is absorbed by a falling film absorption tower, a small amount of phosphorus pentachloride generated flows back to a phosphorus trichloride intermediate tank along with phosphorus trichloride, and the phosphorus trichloride is conveyed to the falling film reactor by a phosphorus trichloride circulating pump for reuse; d) Removing chlorine attached to the surface of the crystal of the refined phosphorus pentachloride obtained in the step c) by a continuous dechlorinating device to obtain a phosphorus pentachloride product; e) Condensing the tail gas generated after condensation in the steps a), b) and c) by a tail gas condenser to recover phosphorus trichloride, and absorbing the phosphorus trichloride by a tail gas absorption tower. Compared with the prior art, the continuous synthesis process and the device for phosphorus pentachloride provided by the invention realize better overall interaction through specific process steps under specific structures and continuous relations, can realize continuous production, have high efficiency and stable and controllable product quality, and can solve the problems of poor process stability, high safety risk in shutdown maintenance and production processes, unsatisfactory occupational health environment, high environment-friendly tail gas treatment and operation cost and the like in the conventional phosphorus pentachloride production process.
To further illustrate the present invention, the following examples are provided for illustration. The raw materials used in the following examples of the present invention are generally commercially available.
Examples
Referring to fig. 1 to 2, wherein fig. 1 is a flowchart of a phosphorus pentachloride continuous synthesis process provided by an embodiment of the present invention, and fig. 2 is a schematic structural diagram of a phosphorus pentachloride continuous synthesis apparatus provided by an embodiment of the present invention; in fig. 2, (1) is a slurry conveying device, (2) is a settler, (3) is a falling film reactor, (4) is a solid-liquid separator, (5) is an intermediate condenser 1, (6) is an intermediate condenser 2, (7) is a first-stage continuous devolatilizer, (8) is a tail gas fan, (9) is a second-stage continuous devolatilizer, (10) is a continuous dechlorinating device, (11) is a phosphorus trichloride circulating pump, (12) is a phosphorus trichloride intermediate tank, (13) is a falling film absorption tower, (14) is a tail gas condenser, (15) is a tail gas absorption tower, (16) is an upper rotary valve, (17) is a lower rotary valve, and (18) is a solid-liquid separation discharge rotary valve.
The test is carried out according to the continuous synthesis process and the device of the phosphorus pentachloride described in the figures 1-2, and the specific process is as follows:
preparing 400Kg of raw material chlorine (steel cylinder) and adding 200Kg of phosphorus trichloride into a phosphorus trichloride intermediate tank (12);
phosphorus trichloride and chlorine are added into a falling film reactor (3) simultaneously for reaction, the continuous adding speed of the phosphorus trichloride is controlled by a phosphorus trichloride circulating pump (11) to be 20Kg/h (12.8L/h), and the continuous feeding flow of the chlorine is 2.2m 3 Controlling the temperature of the falling film reactor (3) at 55 ℃ and the reaction pressure at 0.5KPa;
the obtained mixture slurry of the phosphorus trichloride and the phosphorus pentachloride is settled in a settler (2), the temperature of the settler (2) is 55 ℃, the pressure is 0.5KPa, and the stirring speed is 35rpm; condensing the obtained gas phase by an intermediate condenser 2 (6), wherein the condensing temperature of the intermediate condenser 2 (6) is 12 ℃, the pressure is 0KPa, the liquid phase reflows to the falling film reactor (3), the liquid phase reflows to a phosphorus trichloride intermediate tank (12) after the tail gas passes through a tail gas condenser (14), and the waste gas is discharged into a tail gas absorption tower (15) and absorbed by an absorption liquid;
the mixed slurry of the phosphorus trichloride and the phosphorus pentachloride continuously enters a solid-liquid separator (4) through a slurry conveying device (1), the feed flow rate is controlled to be 9-14L/h, the temperature of the solid-liquid separator (4) is 55 ℃, and the pressure is 0.3KPa; separating by a solid-liquid separator (4), separating liquid-phase phosphorus trichloride, refluxing the liquid-phase phosphorus trichloride to the falling-film reactor (3) (the refluxed phosphorus trichloride contains a small amount of phosphorus pentachloride), separating solid phosphorus pentachloride, and allowing the separated solid phosphorus pentachloride to enter a first-stage continuous devolatilization device (7) (the solid phosphorus pentachloride also contains a small amount of phosphorus trichloride) through a solid-liquid separation discharging rotary valve (18) through a solid-phase outlet;
the phosphorus pentachloride product obtained in the step enters a first-stage continuous devolatilizer (7), phosphorus trichloride in the phosphorus pentachloride is heated and distilled, the heating temperature of the first-stage continuous devolatilizer (7) is 81 ℃, the pressure in the device is 0.5KPa, the material stays in the first-stage continuous devolatilizer (7) for 6min, the distilled phosphorus trichloride is condensed by an intermediate condenser 1 (5) and then flows back to a falling film reactor (3), the condensing temperature of the intermediate condenser 1 (5) is 12 ℃, and the pressure is 0KPa;
the phosphorus pentachloride product obtained in the step is sent to a secondary continuous devolatilization device (9), a certain amount of chlorine gas is introduced, the flow rate of the chlorine gas is 200L/h, the chlorine gas reacts with a small amount of phosphorus trichloride contained in the phosphorus pentachloride to remove the phosphorus trichloride, and the phosphorus pentachloride is further refined to obtain a high-quality phosphorus pentachloride product; controlling the temperature in the secondary continuous devolatilization device (9) at 55 ℃ and the pressure at 0-2 KPa, and keeping the materials in the secondary continuous devolatilization device (9) for 3min;
in the secondary continuous devolatilization device (9) in the step, redundant chlorine is discharged to a falling film absorption tower (13) from a gas phase outlet of the secondary continuous devolatilization device (9), a small amount of phosphorus pentachloride is generated by absorption of phosphorus trichloride in the falling film absorption tower (13) and returns to the falling film reactor (3) for reuse, the temperature of the falling film absorption tower (13) is 15 ℃, the pressure is-0.2 KPa, the circulating flow of the phosphorus trichloride is 124L/h, and the gas phase obtained by the falling film absorption tower (13) enters a same tail gas condenser (14) through a tail gas fan (8);
conveying the obtained phosphorus pentachloride product from a secondary continuous devolatilizer (9) to a continuous dechlorinating device (10) through an upper rotary valve (16), removing a small amount of impurities such as chlorine gas and the like by using carbon dioxide, controlling the dechlorinating temperature at 45 ℃ and the pressure at 5KPa to obtain a qualified phosphorus pentachloride product, and outputting the qualified phosphorus pentachloride product through a lower rotary valve and then packaging; the waste gas is discharged into a tail gas absorption tower (15) and is absorbed by absorption liquid.
The phosphorus pentachloride continuous synthesis process and the device provided by the embodiment of the invention have good continuity in the test process, have no problems of blockage in the middle, unsmooth conveying and the like, and particularly have no chlorine in the system in the shutdown process; tests show that the content of the obtained phosphorus pentachloride is more than 99.5 percent, the phosphorus trichloride content is less than or equal to 0.05 percent, the crystal granularity is uniform, and the product yield is more than 95 percent, which is shown in the following table 1.
Table 1 repeated experimental results of phosphorus pentachloride continuous synthesis process and apparatus provided by the embodiments of the present invention
| Sample numbering | Phosphorus trichloride content | Phosphorus pentachloride content | Remarks (quality standard) |
| 1 | Not detected out | 99.52％ | Phosphorus trichloride is less than or equal to 0.05 percent |
| 2 | Not detected out | 99.57％ | Phosphorus trichloride is less than or equal to 0.05 percent |
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A continuous synthesis process of phosphorus pentachloride comprises the following steps:
a) Reacting phosphorus trichloride and chlorine in a falling-film reactor to obtain a mixture slurry of the phosphorus trichloride and phosphorus pentachloride, condensing the generated gas phase, and refluxing to the falling-film reactor for reuse;
b) Settling the slurry of the mixture of phosphorus trichloride and phosphorus pentachloride obtained in the step a) in a settler, continuously feeding the obtained crystal slurry into a solid-liquid separator through a slurry conveying device for solid-liquid separation, respectively obtaining liquid-phase phosphorus trichloride to flow back to a falling-film reactor, gas-phase phosphorus trichloride to flow back to the falling-film reactor for reuse after condensation, and solid-phase phosphorus pentachloride; condensing the gas phase obtained by settling, and then refluxing the condensed gas phase to the falling film reactor for reuse;
c) Allowing the solid-phase phosphorus pentachloride obtained in the step b) to enter a primary continuous devolatilization device to remove phosphorus trichloride, condensing the obtained gas phase, refluxing the condensed gas phase to a falling film reactor for reuse, allowing the obtained phosphorus pentachloride product to enter a secondary continuous devolatilization device to react with excessive chlorine, and further removing phosphorus trichloride attached to the surface of a phosphorus pentachloride crystal to obtain refined phosphorus pentachloride; unreacted chlorine is absorbed by a falling film absorption tower, a small amount of phosphorus pentachloride generated flows back to a phosphorus trichloride intermediate tank along with phosphorus trichloride, and the phosphorus trichloride is conveyed to the falling film reactor by a phosphorus trichloride circulating pump for reuse;
d) Removing chlorine attached to the surface of the crystal of the refined phosphorus pentachloride obtained in the step c) by a continuous dechlorinating device to obtain a phosphorus pentachloride product;
e) Condensing the tail gas generated in the step a), the step b) and the step c) by a tail gas condenser to recover phosphorus trichloride, and absorbing the phosphorus trichloride by a tail gas absorption tower.
2. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the feeding molar ratio of phosphorus trichloride to chlorine in step a) is 1: (0.4-4.5).
3. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the temperature of the reaction in step a) is 40-75 ℃ and the pressure is 0.1-20 KPa.
4. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the temperature of the sedimentation in step b) is 40-75 ℃, the pressure is 0.1-20 KPa, and the stirring speed is 3-60 rpm.
5. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the flow rate of the solid-liquid separation in step b) is 3L/h to 15L/h, the temperature is 40 ℃ to 75 ℃, and the pressure is 0.1KPa to 1KPa.
6. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the temperature for removing phosphorus trichloride in the first-stage continuous devolatilization device in step c) is 75-90 ℃, the pressure is 0.4-20 KPa, and the retention time is 5-10 min.
7. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the temperature of the reaction between the chlorine gas and the second-stage continuous devolatilizer in step c) is 40-75 ℃, the pressure is-5-10 KPa, and the retention time is 1-5 min.
8. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the temperature absorbed by the falling film absorption tower in step c) is 5-25 ℃ and the pressure is-5 KPa to-0.1 KPa.
9. The continuous synthesis process of phosphorus pentachloride as claimed in claim 1, wherein the temperature for removing chlorine gas attached to the surface of the crystal by the continuous dechlorinating device in step d) is 30-55 ℃, and the pressure is 1-8 KPa.
10. A phosphorus pentachloride continuous synthesis device comprises:
a falling film reactor; the falling film reactor is provided with a chlorine inlet and a phosphorus trichloride inlet; the phosphorus trichloride inlet is also connected with an intermediate condenser;
the feed inlet is connected with the discharge port of the falling film reactor;
the slurry conveying device is connected with the feed inlet and the discharge outlet of the settler;
the feed inlet is connected with the discharge port of the slurry conveying device; the liquid phase outlet of the solid-liquid separator is connected with the phosphorus trichloride inlet of the falling film reactor, and the gas phase outlet is connected with the phosphorus trichloride inlet of the falling film reactor through an intermediate condenser;
a first-stage continuous devolatilization device with a feed inlet connected with a solid phase outlet of the solid-liquid separator; the gas phase outlet of the first-stage continuous devolatilization device is connected with the phosphorus trichloride inlet of the falling film reactor through an intermediate condenser;
a second-stage continuous devolatilization device with a feed port connected with a solid phase outlet of the first-stage continuous devolatilization device; the secondary continuous devolatilization device is provided with a chlorine inlet, a chlorine outlet and a phosphorus pentachloride outlet; the chlorine outlet is also connected with a falling film absorption tower; the phosphorus pentachloride outlet is sequentially connected with an upper rotary valve, a continuous dechlorinating device and a lower rotary valve;
a phosphorus trichloride intermediate tank with a feed inlet connected with a liquid phase outlet of the falling film absorption tower; the phosphorus trichloride intermediate tank is connected with a phosphorus trichloride inlet of the falling film reactor through a phosphorus trichloride circulating pump;
the tail gas condenser is connected with a tail gas outlet of the middle condenser through a gas inlet; and a liquid phase outlet of the tail gas condenser is connected with a feed inlet of the phosphorus trichloride intermediate tank, and a gas phase outlet of the tail gas condenser is also connected with a tail gas absorption tower.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4335085A (en) * | 1980-03-04 | 1982-06-15 | Hoechst Aktiengesellschaft | Process for the preparation of phosphorus pentachloride |
| CN102320584A (en) * | 2011-10-26 | 2012-01-18 | 核工业理化工程研究院华核新技术开发公司 | Method for preparing phosphorus pentafluoride |
| CN202246070U (en) * | 2011-06-16 | 2012-05-30 | 江苏大明科技有限公司 | Production system for synthesizing orthophosphorous acid by hydrolyzing phosphorus trichloride |
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- 2023-02-14 CN CN202310115606.9A patent/CN115974018B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4335085A (en) * | 1980-03-04 | 1982-06-15 | Hoechst Aktiengesellschaft | Process for the preparation of phosphorus pentachloride |
| CN202246070U (en) * | 2011-06-16 | 2012-05-30 | 江苏大明科技有限公司 | Production system for synthesizing orthophosphorous acid by hydrolyzing phosphorus trichloride |
| CN102320584A (en) * | 2011-10-26 | 2012-01-18 | 核工业理化工程研究院华核新技术开发公司 | Method for preparing phosphorus pentafluoride |
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