CN114106328B - Method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production - Google Patents
Method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production Download PDFInfo
- Publication number
- CN114106328B CN114106328B CN202111537274.0A CN202111537274A CN114106328B CN 114106328 B CN114106328 B CN 114106328B CN 202111537274 A CN202111537274 A CN 202111537274A CN 114106328 B CN114106328 B CN 114106328B
- Authority
- CN
- China
- Prior art keywords
- sodium sulfide
- sulfide
- sodium
- polyhydrate
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 title claims abstract description 123
- 229910052979 sodium sulfide Inorganic materials 0.000 title claims abstract description 112
- 238000000034 method Methods 0.000 title claims abstract description 46
- 239000004734 Polyphenylene sulfide Substances 0.000 title claims abstract description 41
- 229920000069 polyphenylene sulfide Polymers 0.000 title claims abstract description 41
- 230000019086 sulfide ion homeostasis Effects 0.000 title claims abstract description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 87
- 239000007788 liquid Substances 0.000 claims abstract description 56
- 230000018044 dehydration Effects 0.000 claims abstract description 49
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 49
- 238000004519 manufacturing process Methods 0.000 claims abstract description 18
- 238000000926 separation method Methods 0.000 claims abstract description 14
- 238000006243 chemical reaction Methods 0.000 claims description 63
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 claims description 30
- OCJBOOLMMGQPQU-UHFFFAOYSA-N 1,4-dichlorobenzene Chemical compound ClC1=CC=C(Cl)C=C1 OCJBOOLMMGQPQU-UHFFFAOYSA-N 0.000 claims description 23
- 239000007789 gas Substances 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 20
- 239000011259 mixed solution Substances 0.000 claims description 20
- 239000000243 solution Substances 0.000 claims description 19
- 238000002844 melting Methods 0.000 claims description 18
- 230000008018 melting Effects 0.000 claims description 18
- 239000011552 falling film Substances 0.000 claims description 14
- 239000002912 waste gas Substances 0.000 claims description 14
- 238000006116 polymerization reaction Methods 0.000 claims description 10
- 239000011734 sodium Substances 0.000 claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 8
- 229910052708 sodium Inorganic materials 0.000 claims description 6
- 238000002425 crystallisation Methods 0.000 claims description 5
- 230000008025 crystallization Effects 0.000 claims description 5
- 230000002776 aggregation Effects 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 4
- 238000005054 agglomeration Methods 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 238000010309 melting process Methods 0.000 claims description 2
- 238000004064 recycling Methods 0.000 claims description 2
- 230000000630 rising effect Effects 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 16
- 229920006389 polyphenyl polymer Polymers 0.000 abstract 2
- 150000003568 thioethers Chemical class 0.000 abstract 2
- 238000003723 Smelting Methods 0.000 abstract 1
- 239000011541 reaction mixture Substances 0.000 abstract 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 24
- 235000011121 sodium hydroxide Nutrition 0.000 description 21
- 239000000047 product Substances 0.000 description 17
- 238000010521 absorption reaction Methods 0.000 description 9
- 238000005516 engineering process Methods 0.000 description 9
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 6
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- 239000003513 alkali Substances 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000012752 auxiliary agent Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000012295 chemical reaction liquid Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000006068 polycondensation reaction Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 229920013632 Ryton Polymers 0.000 description 1
- 239000004736 Ryton® Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000000071 blow moulding Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000011437 continuous method Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 238000004372 laser cladding Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000007344 nucleophilic reaction Methods 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000011555 saturated liquid Substances 0.000 description 1
- 230000037390 scarring Effects 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000003856 thermoforming Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G75/00—Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen, or carbon in the main chain of the macromolecule
- C08G75/02—Polythioethers
- C08G75/0204—Polyarylenethioethers
- C08G75/0277—Post-polymerisation treatment
- C08G75/0281—Recovery or purification
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/22—Evaporating by bringing a thin layer of the liquid into contact with a heated surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/30—Accessories for evaporators ; Constructional details thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/30—Accessories for evaporators ; Constructional details thereof
- B01D1/305—Demister (vapour-liquid separation)
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/52—Hydrogen sulfide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Polymers & Plastics (AREA)
- Medicinal Chemistry (AREA)
- Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)
Abstract
The invention relates to the technical field of sodium sulfide dehydration, in particular to a method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production. The specific technical scheme is as follows: a process for continuously dewatering sodium sulfide in polyphenyl thioether production includes such steps as smelting sodium sulfide and sodium hydroxide under negative pressure, gas-liquid separation under vacuum, adding the separated sodium sulfide liquid to the heated reactor containing the reaction mixture for preparing polyphenyl thioether, and condensing for recovering the separated gas. The invention solves the problems that in the existing dehydration process in PPS production, each kettle is finished intermittently and independently, the production time is long, the dehydration amount is unstable each time, the dehydration liquid contains a large amount of NMP and needs to be subjected to secondary rectification, fresh NMP is supplemented into the kettle, and the like.
Description
Technical Field
The invention relates to the technical field of sodium sulfide dehydration, in particular to a method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production.
Background
Polyphenylene Sulfide (PPS) resin is a special resin with excellent performance, and gradually becomes one of special engineering materials with the highest cost performance in the last decade. Various production processes for producing PPS are available, and the current industrialization is mature sodium sulfide method, the technology is developed in the last sixty years from Philips oil company in the United states, formal industrialization is performed in 1973, after the patents of the company expire in 1984, european and Japanese countries develop different process routes respectively based on the original technology and the same production principle, especially the Japanese Industrial development of PPS with the characteristics of itself, and then the large-scale industrial development of ink in Japanese, tosoh, kagaku, etc. have established factories, and the PPS service of Ryton is purchased in Soy in 2014.
The sodium sulfide method for industrially producing PPS in China is also based on the original technology in the United states, namely, paradichlorobenzene and partially dehydrated polycrystalline sodium sulfide are subjected to polycondensation reaction in N-methylpyrrolidone (NMP) solution under the action of lithium chloride auxiliary agent and at a certain temperature, pressure and time.
The technology has the advantages that the main raw materials of the anhydrous crystalline sodium sulfide are low in cost and easy to obtain, the paradichlorobenzene is easy to obtain, the reaction is controllable, the linearity of the PPS resin product is high, but the technology has the defects of large circulation amount of solvent, more byproducts, enrichment of the byproducts in the solvent, residue in the product, and the whole production technology is behind, particularly, dehydration is finished by respectively heating after mixing with auxiliary agents such as NMP, lithium chloride and the like, hydrolysis-resistant sodium hydroxide and the like in a reaction kettle, the technology is not controlled, the dehydration is unstable, and the molecular weight of the product is also unstable; the NMP solvent carried out by dehydration is large in quantity and takes a large amount of time, and the subsequent recovery consumes a large amount of energy by rectification; the polymerization and crystallization processes are controlled singly, so that the molecular weight of the polymer is unstable, the granularity is unstable, and the product variety is single; the separation process is unreasonable, so that the system is difficult to operate, the energy consumption is high, the solvent consumption is high, the design of the auxiliary lithium chloride recovery process is unreasonable, the loss is large, a large amount of environment-friendly waste residues are difficult to treat, the auxiliary recovery is poor, and the product cost is quite high.
The improvement of the process control conditions of the technology is remarkable in improving the PPS impact and toughness, a third substance is introduced in the reaction to reduce the crystallinity, so that the resin product is suitable for a printed circuit board, and a novel method for removing a large amount of sodium chloride plasma impurities from the prepolymer, shortening the polymerization time and reducing the equipment cost is also researched. Foreign PPS products generally have tens of basic variety brands, but also have more specialized brands such as fiberglass and carbonate fiber reinforced grades, inorganic filler grades, blend alloy grades, etc., and particularly in recent years applications have been expanded to high heat conduction grades, laser cladding grades, high frequency component grades, low die carbon build-up grades, etc., PPS processing has been expanded from more single injection molding processes to coating, fiber, film, extrusion, controlled blow molding, thermoforming, and electronic/electrical, etc.
Therefore, although it is realized that the performance of the PPS product is single in China, the number of brands is limited greatly, the process has more problems, the running cost is high, the competitiveness is poor, etc., but the research of research units and universities is not enough to be combined with the enterprise because the enterprise performs less substantial research, the PPS production process technology is still at a lower level, and especially the production reliability and continuous stability are quite poor.
The method is characterized in that the reaction raw material sodium sulfide is obtained by dehydrating the poly-water crystal sodium sulfide in a mixed solution at present, and can also be obtained by reacting sodium hydrosulfide with sodium hydroxide, and for dehydration, excessive moisture can bring about the increase of reaction pressure, the synthesis failure can be caused by the fact that the molar ratio of the poly-water crystal sodium sulfide to paradichlorobenzene exceeds a high limit, and certain moisture exists in materials which finally participate in the reaction, so that the water and a solvent are required to have a synergistic effect, nucleophilic reaction is facilitated, the reactivity of chlorine on a benzene ring is increased, substitution polymerization is easy to occur, the polycondensation reaction is smoothly carried out, and the synthesis failure can be caused by the fact that the molar ratio of the poly-water crystal sodium sulfide to paradichlorobenzene exceeds a low limit, so that the water content is particularly important to control.
In the existing production process, dehydration is respectively completed in a reaction kettle under normal pressure, sodium sulfide, NMP, sodium hydroxide and lithium chloride are respectively added into the reaction kettle, mixed dehydration is performed, the temperature is controlled to be more than 200 ℃, 1.0MPa steam and other heat sources (such as electric heating or heat conducting oil) are required to be jointly completed, the dehydration time is 3-5 hours, the dehydration liquid enters a collecting tank, the NMP content in the dehydration liquid is usually 50% -80%, a large amount of secondary separation and the replenishment of a large amount of solvent NMP are caused, the energy consumption and the cost are high, the dehydration amount is unstable, the quality of a synthesized product is unstable, meanwhile, the dehydration is intermittent dehydration, and the use time of a large amount of reaction kettles is occupied once the dehydration is performed, so the meaning of setting a common continuous control dehydration device is particularly important.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for continuously dehydrating sodium sulfide in polyphenylene sulfide production, which solves the problems that in the existing dehydration process in PPS production, the production time is long, the dehydration amount is unstable each time, the dehydration liquid contains a large amount of NMP and needs to be subjected to secondary rectification, fresh NMP is supplemented into a kettle, and the like.
In order to achieve the above purpose, the invention is realized by the following technical scheme:
the invention discloses a method for continuously dehydrating sodium sulfide in polyphenylene sulfide production, which is characterized in that sodium sulfide and sodium hydroxide are melted in a negative pressure state, gas-liquid separation is carried out under a vacuum condition, separated sodium sulfide liquid is added into a heated reaction kettle containing a reaction mixed liquid for producing polyphenylene sulfide, and separated gas is condensed and recovered.
Preferably, the sodium sulfide polyhydrate is Na 2 S·3H 2 O、Na 2 S·5H 2 O or Na 2 S·9H 2 O。
Preferably, the molar ratio of the sodium sulfide polyhydrate to the sodium hydroxide is 0.5-1.5:0.01-0.5.
Preferably, the melting temperature of the sodium sulfide polyhydrate is 50-120 ℃, and the negative pressure is minus 0.005-minus 0.01Mpa.
Preferably, the temperature of the gas-liquid separation is 150-200 ℃, and the pressure is-0.03 to-0.08 Mpa.
Preferably, the mixed gas and gas-liquid separated gas generated in the melting process of sodium sulfide and sodium hydroxide are treated by an exhaust gas treatment tower and then exhausted.
Preferably, the reaction mixed solution is a mixed solution of NMP and lithium chloride, and the reaction mixed solution is heated to 150-180 ℃ in a reaction kettle under the nitrogen atmosphere; adding dehydrated sodium sulfide liquid and melted paradichlorobenzene, sealing the reaction kettle, stopping introducing nitrogen, and keeping the reaction kettle in an anaerobic state; and then, carrying out temperature-rising reaction on the mixed solution in the reaction kettle, and carrying out polymerization reaction under a certain pressure to finally obtain the polyphenylene sulfide product.
Preferably, the molar ratio of the sodium sulfide to the NMP to the lithium chloride is 0.5-1.5:3-5.5:0.3-1.
Preferably, the heating temperature of the paradichlorobenzene is 70-85 ℃, the paradichlorobenzene is heated until the paradichlorobenzene is in a molten state, and the molar ratio of the dehydrated sodium sulfide added into the reaction kettle to the paradichlorobenzene is 1:1.01-1.03.
Preferably, the heating reaction comprises the following steps: firstly, heating to 200-240 ℃ and reacting for 1-1.5 h; then continuously heating to 250-265 ℃ for 2-3.5 h; finally cooling to 110-130 ℃, and the crystallization and agglomeration time of the product is 2-3 h.
The invention has the following beneficial effects:
1. according to the invention, the dehydration process of the sodium sulfide with multiple water is carried out independently, each reaction kettle is not provided with a dehydration task, the dehydration time is changed from 3-5 hours to 3-10 minutes, and the operation efficiency of the reaction kettle is greatly saved. Meanwhile, the water is not mixed with auxiliary agents such as NMP, lithium chloride and the like any more, but the NMP and the water are not separated together, so that the water removal amount is difficult to measure, and the problem of secondary rectification energy consumption of a large amount of NMP and water separation is generated in the subsequent process, so that the whole process is more optimized and reliable.
2. The invention adopts a continuous method for dehydration, is not mixed with NMP and lithium chloride during dehydration and is not carried out in a reaction kettle, so that the dehydration is more stable and continuous, NMP is not contained in dehydration liquid, the dehydration rate is stably controlled, the dehydration amount of sodium sulfide is completely controlled, and a set of dehydration equipment can be operated for a plurality of reaction kettles to use qualified dehydrated sodium sulfide solution, thereby saving a large amount of operation time, indirectly reducing the number of the reaction kettles and saving a large amount of investment and operation cost.
3. By adopting the dehydration method, the dehydrated liquid obtained after the separation of the sodium sulfide with water by the gas-liquid separator does not contain NMP, so that the secondary separation cost is reduced, the addition amount of NMP added again is reduced, the key is that the water content in the reaction liquid is stabilized, the quality of the product is stabilized, a large amount of energy sources are saved, and great economic and social benefits are generated.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The technical means used in the examples are conventional means well known to those skilled in the art unless otherwise indicated.
The devices mentioned and used in the present invention are all existing devices, and for convenience in describing the processing procedure of the present invention, the parts mainly used in the devices are described in the related manner, and the parts not mentioned should be understood to be all existing devices and have corresponding functions.
1. The invention discloses a method for continuously dehydrating sodium sulfide in polyphenylene sulfide production, which comprises the steps of melting sodium sulfide and sodium hydroxide in a micro negative pressure state, then carrying out gas-liquid separation under a vacuum condition, adding the separated sodium sulfide liquid into a heated reaction kettle containing a reaction mixed liquid for producing polyphenylene sulfide, and condensing and recycling the separated gas.
Wherein the sodium sulfide polyhydrate is Na 2 S·3H 2 O、Na 2 S·5H 2 O or Na 2 S·9H 2 O. The molar ratio of the sodium sulfide polyhydrate to the sodium hydroxide is 0.5-1.5:0.01-0.5. The melting temperature of the sodium sulfide polyhydrate is 50-120 ℃, and the negative pressure is minus 0.005-minus 0.01Mpa (G). The temperature of gas-liquid separation is 150-200 ℃, and the pressure is-0.03 to-0.08 Mpa.
It should be noted that: the melting of sodium sulfide and sodium hydroxide in the melting vessel. The melting tank disclosed in this embodiment is a closed rectangular heating device with an overflow baffle, a steam coil, a feed inlet and an extraction opening, sodium sulfide and sodium hydroxide are poured into a front tank of the overflow baffle and heated and melted by coil steam, then flow into a rear tank of the overflow baffle through the overflow baffle with a certain height, and then a conveying pump sucks molten sodium sulfide solution with sodium hydroxide from the bottom of the rear tank of the overflow baffle into a falling film evaporator. The overflow baffle front groove can be used for blocking the sedimentation of solid impurities in the sodium sulfide polyhydrate, so that the cleanness of sodium sulfide solution conveyed by the rear groove is ensured; meanwhile, the raw material requirement of continuous dehydration can be realized by continuously controlling the liquid level to control the adding of sodium sulfide and sodium hydroxide in equal proportion into the front tank. Wherein, the sodium hydroxide is added mainly to reduce the hydrolysis of sodium sulfide, and the micro negative pressure state in the melting tank is realized by the air extraction opening arranged at the top of the melting tank and the suction pipe connected with the air extraction opening, specifically: the water vapor, dust and trace hydrogen sulfide gas, air and the like generated by the hydrolysis of trace sodium sulfide generated in the process of melting the sodium sulfide are pumped into the waste gas treatment tower, when the waste gas is cooled, washed and absorbed, the volume can be reduced, and when the treated waste gas is emptied by adopting a high-level chimney, the waste gas absorption tower can present micro negative pressure, and the other end of the connecting suction pipe is connected to the inlet of the tower, so that the dissolution tank is in a micro negative pressure state.
Further, a liquid level meter (or an on-line liquid level detection device) is arranged in the melting tank, and the liquid level measured by the liquid level meter is used for controlling the adding amount of sodium sulfide and sodium hydroxide; meanwhile, a flowmeter and a control valve are arranged at the outlet of the sodium sulfide mixed solution delivery pump and are used for controlling the quantity of the sodium sulfide mixed solution which is added into the falling film evaporator and is required to be stable.
In the embodiment, the mixed solution of the sodium sulfide and the sodium hydroxide after being melted is subjected to gas-liquid separation by a falling film evaporator. The falling film evaporator used in the invention is a single-tube falling film evaporator, the heating medium is heat conduction oil, the temperature of the heat conduction oil is between 180 and 220 ℃, the bottom of the falling film evaporator is provided with a gas-liquid separator in a matching way, the gas-liquid separator is internally provided with a space for separating enough gas from liquid, and the middle part in the space is provided with a baffle plate which is arranged in a staggered way. The inner top of the gas-liquid separator is provided with a silk screen foam removing device, the outer top is provided with negative pressure equipment, and the bottom is provided with a conveying pump and a pipeline. According to the liquid level (the liquid level can be monitored by a liquid level meter) and a flowmeter arranged at the outlet, the materials are fed into a plurality of reaction kettles (namely dehydrated sodium sulfide is added), and meanwhile, the accuracy of measuring the amount of sodium sulfide solution entering each reaction kettle is ensured.
It should be noted that: the liquid level here is linked with a flowmeter arranged on the feeding pipe of the falling film evaporator (namely a flowmeter arranged at the outlet of the delivery pump). When the discharging requirement of the gas-liquid separator changes, the liquid level of the gas-liquid separator changes, and the opening of the feeding valve (namely the feeding valve arranged on the feeding pipe of the falling film evaporator) is changed in a linkage mode, so that the quantity of the sodium sulfide mixed solution added into the falling film evaporator is ensured.
Further, a flowmeter and a control valve are arranged on the heat conducting oil feeding pipe, and the quantity of the heat conducting oil in the pipeline is controlled by the detected concentration of the dehydrated sodium sulfide; the gas-liquid separator is provided with a temperature measuring instrument and a pressure measuring instrument, so that the temperature in the gas-liquid separator is controlled at 150-200 ℃; the pressure of the gas-liquid separator is controlled to be-0.03 to-0.08 Mpa by adjusting the rotating speed of the negative pressure vacuum pump through a pressure measuring instrument. Finally, the sodium sulfide concentration is obtained by measuring the temperature and the pressure, so that the heat conduction oil flow control valve is adjusted, and the following needs to be described: when the pressure is fixed, a certain temperature corresponds to a certain sodium sulfide concentration, if the pressure is changed, the temperature corresponding to a sodium sulfide solution with a certain concentration is also changed, so that the concentration can be calculated by using y=F T, P function (F represents function, T represents temperature, P represents pressure, y represents concentration), and when the pressure is fixed, the temperature (heat exchange) of the sodium sulfide solution can be controlled by controlling the flow of heat conducting oil, so that the concentration of the sodium sulfide solution is controlled.
It should be noted that: the water content of the sodium sulfide solution after dewatering the sodium sulfide polyhydrate is determined according to the concentration of the sodium sulfide solution, and the concentration of the sodium sulfide solution is determined according to the temperature, pressure and solubility relation curve of the sodium sulfide solution. During dehydration, hydrogen sulfide gas generated by partial hydrolysis of sodium sulfide is separated from water in a cooling device and pumped by a vacuum pump to be sent into a hydrogen sulfide waste gas treatment tower for waste gas treatment, namely, gas separated by a gas-liquid separator of sodium sulfide in a multi-water way is firstly sent into the cooling device for condensation and condensate water recovery, and waste gas (such as hydrogen sulfide gas) contained in the gas is pumped into the waste gas treatment tower by the vacuum pump for washing and absorption by caustic soda liquid and then is exhausted.
Specific: the cooling equipment used in the invention is an indirect vertical surface condenser, and the cooling medium is circulating industrial water; the waste gas treatment tower is a two-layer packed tower and is provided with an alkali liquor circulating absorption system, and the waste gas treatment tower comprises a pump, a raw material tank, an absorption liquid storage tank and a pipeline, wherein the absorption tank is a double tank, one circulation tank is used for alkali distribution and standby, the absorption is close to saturation for reverse tank, and saturated liquid is sent to the absorption liquid storage tank. The exhaust gas treatment tower outlet pipeline is provided with a hydrogen sulfide detector in the exhaust gas, and the alkali liquor circulation pipe is provided with a sodium hydroxide concentration detector to ensure that the environment protection absolutely meets the standard.
The specific dehydration process of the sodium sulfide polyhydrate comprises the following steps:
adding sodium sulfide and sodium hydroxide into a melting tank, melting at 50-120deg.C by using steam as heat source, and sucking waste gas under micro negative pressure at-0.005 to-0.01 Mpa (G). Dewatering sodium sulfide in a falling film evaporator with heat conducting oil as heat exchange medium, and separating gas and liquid in a gas-liquid separator with pressure of-0.03 to-0.08 MPa (G), wherein the water content of the dewatered sodium sulfide is determined by sodium sulfide concentration, the concentration is determined by temperature and pressure, and the temperature is controlled to be 150-200 ℃; sodium sulfide was added to a heated reaction vessel containing NMP and lithium chloride.
2. After the sodium sulfide dehydrate is completed according to the method 1, the sodium sulfide dehydrate is added into a reaction kettle which is heated and contains a reaction mixed solution for producing the polyphenylene sulfide to participate in the production of the polyphenylene sulfide. And adding sodium sulfide solution into the reaction kettle by adopting a submerged pump or a suction pump.
Specific: the reaction mixed solution is the mixed solution of NMP and lithium chloride, and before the sodium sulfide liquid is added into a reaction kettle, the mixed solution of NMP and anhydrous lithium chloride which are metered into the reaction kettle is heated to 150-180 ℃ by steam through a coil under the conditions of stirring and nitrogen atmosphere; then adding a prescribed amount of dehydrated sodium sulfide mixed liquid, and sealing the reaction kettle; then adding the melted paradichlorobenzene solution, and stopping introducing nitrogen to keep the oxygen-free state in the reaction kettle all the time; and finally, carrying out stepwise heating reaction on the mixed solution in the reaction kettle, and carrying out two-step polymerization reaction at a certain pressure (the pressure naturally generated in the reaction kettle) in the earlier stage and the later stage to finally obtain the polyphenylene sulfide product.
Wherein, the mol ratio of sodium sulfide, NMP and lithium chloride is 0.5-1.5:3-5.5:0.3-1, and is preferably: 1:4.5:0.55. The heating temperature of the paradichlorobenzene is 70-85 ℃, the paradichlorobenzene is heated until the paradichlorobenzene is in a molten state, and the molar ratio of sodium sulfide liquid to paradichlorobenzene added into the reaction kettle is 1:1.01-1.03. In the whole reaction system in the reaction kettle, the water content is the water content corresponding to the concentration of dehydrated sodium sulfide.
The step-by-step temperature rising reaction comprises the following steps: in a reaction kettle, firstly heating to 200-240 ℃ to perform a preliminary polymerization reaction, wherein the reaction time is 1-1.5 h; then continuously heating to 250-265 ℃ to carry out post polymerization reaction for 2-3.5 h; finally cooling to 110-130 ℃, and finally completing the production of the polyphenylene sulfide product, wherein the crystallization and agglomeration time of the product is 2-3 h.
The invention is further illustrated below in conjunction with specific examples.
Examples
Referring to fig. 1, the dehydration process of sodium sulfide polyhydrate and the production process of polyphenylene sulfide are as follows:
(1) Early preparation: firstly, starting an alkali liquor absorption hydrogen sulfide absorption tower device (namely an exhaust gas treatment tower), starting a melting tank extraction valve, starting cooling water connected with a surface condenser of a sodium sulfide dehydration gas-liquid separator, starting a vacuum pump, and setting vacuum degree control into automatic control.
(2) The sodium sulfide and sodium hydroxide are fed into the front tank of the melting tank by a conveying pump with conveying control, heating steam is started and stirring is carried out, the stirring process is continued all the time, the molten sodium sulfide overflows into the rear tank with steam heating, the molten sodium sulfide is conveyed into a single-tube falling film evaporator with feeding flow control by pumping, the molten sodium sulfide is heated to 150-200 ℃ by heat conducting oil, dehydration is carried out to required quantity under-0.03 to-0.08 Mpa (G), gas generated in the gas-liquid separation process enters a surface condenser to be condensed into condensed water to be collected, and waste gas is pumped by a vacuum pump to be conveyed into a waste gas treatment tower to be treated and then is discharged. The dehydrated sodium sulfide solution containing a certain amount of sodium hydroxide is metered by a pump and a pipeline and then is sent to a reaction kettle needing to be fed, and the reaction solution is prepared by mixing NMP and lithium chloride in a nitrogen atmosphere heated to 150-180 ℃.
The required amounts here refer to: after dehydration is completed, the water content in the required sodium sulfide is determined according to the water content in the sodium sulfide, namely, the sodium sulfide concentration is determined according to a solubility curve of the sodium sulfide in water under a certain temperature and pressure. The dehydration method has strong continuity, does not cause scarring in the existing production, and dehydrates together with NMP to cause a large amount of NMP-carrying phenomenon.
(3) Adding heated paradichlorobenzene into the reaction liquid obtained in the step (2) by a pump, wherein the heating temperature of the paradichlorobenzene is 70-85 ℃, so that paradichlorobenzene solid is melted, and the adding amount is that the molar ratio of sodium sulfide content to paradichlorobenzene after dehydration is 1:1.01-1.03. After the reaction kettle is added, the reaction kettle is closed first, and then nitrogen is closed. The mixed solution in the reaction kettle is subjected to step-by-step heating reaction by using heat conduction oil, and the method specifically comprises the following steps: firstly, heating to 200-240 ℃ to perform a preliminary polymerization reaction, preferably 225 ℃, and reacting for 1-1.5 h; continuously heating to 250-265 ℃ for post polymerization reaction, preferably 260 ℃, and reacting for 2-3.5 h; and then cooling to 110-130 ℃, preferably 130 ℃, wherein the crystallization and aggregation time of the product is 2-3 h during cooling, so that the polymer is aggregated and crystallized, and finally the production of the polyphenylene sulfide product is completed.
The sodium sulfide dehydrate treatment was performed in the polyphenylene sulfide production using the above method, and specific reaction conditions of each example are shown in table 1 below.
TABLE 1 dehydration conditions for sodium sulfide polyhydrate
After dehydration of sodium sulfide polyhydrate according to the dehydration conditions shown in table 1 above, sodium sulfide content in the dehydrated sodium sulfide solution was analyzed at different dehydration times and temperatures, and specific results are shown in table 2 below. Because the dehydration process of the sodium sulfide is continuous in the invention, 10-15 s refers to the time required for the mixed solution of the melted sodium sulfide and sodium hydroxide to enter and exit the falling film evaporator, and the whole process is continuously operated.
Table 2 dehydration conditions of sodium sulfide polyhydrate in examples
The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.
Claims (8)
1. A method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production is characterized by comprising the following steps: melting sodium sulfide and sodium hydroxide in a negative pressure state, performing gas-liquid separation under a vacuum condition, adding the separated sodium sulfide liquid into a heated reaction kettle containing a reaction mixed liquid for producing polyphenylene sulfide, and condensing and recycling the separated gas;
the melting temperature of the sodium sulfide polyhydrate is 50-120 ℃, the negative pressure is minus 0.005-minus 0.01Mpa, the temperature of the gas-liquid separation is 150-200 ℃, and the pressure is minus 0.03-minus 0.08Mpa;
the melting of the sodium sulfide and the sodium hydroxide is carried out in a melting tank, after being poured into a front tank of an overflow baffle plate and heated and melted by coil pipe steam, the sodium sulfide and the sodium hydroxide flow into a rear tank of the overflow baffle plate through the overflow baffle plate with a certain height, and then molten sodium sulfide solution with the sodium hydroxide is pumped into a falling film evaporator from the bottom of the rear tank of the overflow baffle plate by a delivery pump; the time required for the mixed solution of the melted sodium sulfide and sodium hydroxide to enter and exit the falling film evaporator is 10-15 s.
2. The method for producing polyphenylene sulfide according to claim 1The continuous dehydration method of sodium sulfide is characterized in that: the sodium sulfide polyhydrate is Na 2 S·3H 2 O、 Na 2 S·5H 2 O or Na 2 S·9H 2 O。
3. The method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production according to claim 1, wherein the method comprises the following steps: the molar ratio of the sodium sulfide polyhydrate to the sodium hydroxide is 0.5-1.5:0.01-0.5.
4. The method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production according to claim 1, wherein the method comprises the following steps: and (3) treating the mixed gas generated in the mixed melting process of the sodium sulfide and the sodium hydroxide and the gas separated from the gas and the liquid by a waste gas treatment tower and then evacuating.
5. The method for continuously dehydrating sodium sulfide polyhydrate in the production of polyphenylene sulfide according to any one of claims 1 to 4, wherein: the reaction mixed solution is a mixed solution of NMP and lithium chloride, and is heated to 150-180 ℃ in a reaction kettle under the nitrogen atmosphere; adding dehydrated sodium sulfide liquid and melted paradichlorobenzene, sealing the reaction kettle, stopping introducing nitrogen, and keeping the reaction kettle in an anaerobic state; and then, carrying out temperature-rising reaction on the mixed solution in the reaction kettle, and carrying out polymerization reaction under a certain pressure to finally obtain the polyphenylene sulfide product.
6. The method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production according to claim 5, wherein the method comprises the following steps: the molar ratio of the sodium sulfide to the NMP to the lithium chloride is 0.5-1.5:3-5.5:0.3-1.
7. The method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production according to claim 5, wherein the method comprises the following steps: the heating temperature of the paradichlorobenzene is 70-85 ℃, the paradichlorobenzene is heated until the paradichlorobenzene is in a molten state, and the molar ratio of the dehydrated sodium sulfide added into the reaction kettle to the paradichlorobenzene is 1:1.01-1.03.
8. The method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production according to claim 5, wherein the method comprises the following steps: the temperature rising reaction comprises the following steps: firstly, heating to 200-240 ℃ and reacting for 1-1.5 h; then continuously heating to 250-265 ℃ for 2-3.5 h; finally cooling to 110-130 ℃, and the crystallization and agglomeration time of the product is 2-3 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111537274.0A CN114106328B (en) | 2021-12-15 | 2021-12-15 | Method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111537274.0A CN114106328B (en) | 2021-12-15 | 2021-12-15 | Method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114106328A CN114106328A (en) | 2022-03-01 |
| CN114106328B true CN114106328B (en) | 2023-09-08 |
Family
ID=80364812
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111537274.0A Active CN114106328B (en) | 2021-12-15 | 2021-12-15 | Method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114106328B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115212706B (en) * | 2022-07-11 | 2023-08-18 | 江苏楷鼎环保装备有限公司 | Tail gas treatment method for sulfur black dye production system |
| CN117343327B (en) * | 2023-11-09 | 2024-07-30 | 浙江新和成特种材料有限公司 | Low-volatile crosslinked polyphenylene sulfide and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06247704A (en) * | 1993-02-23 | 1994-09-06 | Nagao Kk | Dehydrating method of sodium sulfide |
| CN104163402A (en) * | 2014-07-18 | 2014-11-26 | 中国石油化工股份有限公司 | Preparation method of anhydrous sodium sulfide |
| CN105778093A (en) * | 2016-03-21 | 2016-07-20 | 成都大诺工程技术咨询有限公司 | Halogen-free catalytic polyphenylene sulfide and preparation method thereof |
| CN111253573A (en) * | 2019-12-28 | 2020-06-09 | 重庆聚狮新材料科技有限公司 | Method for preparing polyphenylene sulfide resin |
| CN113087906A (en) * | 2021-04-07 | 2021-07-09 | 四川轻化工大学 | Preparation method of polyphenylene sulfide ketone and product thereof |
-
2021
- 2021-12-15 CN CN202111537274.0A patent/CN114106328B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06247704A (en) * | 1993-02-23 | 1994-09-06 | Nagao Kk | Dehydrating method of sodium sulfide |
| CN104163402A (en) * | 2014-07-18 | 2014-11-26 | 中国石油化工股份有限公司 | Preparation method of anhydrous sodium sulfide |
| CN105778093A (en) * | 2016-03-21 | 2016-07-20 | 成都大诺工程技术咨询有限公司 | Halogen-free catalytic polyphenylene sulfide and preparation method thereof |
| CN111253573A (en) * | 2019-12-28 | 2020-06-09 | 重庆聚狮新材料科技有限公司 | Method for preparing polyphenylene sulfide resin |
| CN113087906A (en) * | 2021-04-07 | 2021-07-09 | 四川轻化工大学 | Preparation method of polyphenylene sulfide ketone and product thereof |
Non-Patent Citations (1)
| Title |
|---|
| 冯辉霞，等."聚苯硫醚的硫化钠法常压合成实验研究及其结构表征".《化工科技》.2007,第15卷(第6期),第9-14页. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114106328A (en) | 2022-03-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114106328B (en) | Method for continuously dehydrating sodium sulfide polyhydrate in polyphenylene sulfide production | |
| CN110818898B (en) | Method for dehydrating sodium sulfide dihydrate in polyphenylene sulfide production | |
| CN112811444B (en) | PTA incineration boiler ash solution salt separation crystallization process | |
| CN105366751B (en) | A kind of energy saving and environment friendly comprehensive reutilization method of coal chemical industry gasification washing Heisui River high temperature flashed vapour | |
| CN203741248U (en) | Improved oxidation reaction and tail gas adsorption device for synthesizing glyoxylic acid | |
| CN101875596B (en) | Process for reclaiming chloromethane | |
| CN108862348B (en) | Method for recycling waste sulfuric acid generated by electrode foil corrosion | |
| WO2024139502A1 (en) | High-whiteness and low-impurity-content polyarylether and preparation method therefor | |
| CN209809545U (en) | Six-effect tube type falling film evaporator set | |
| CN216737932U (en) | Electrolytic waste residue and fluorine-containing wastewater treatment device for electrolytic fluorine production process | |
| CN207641007U (en) | Potassium permanganate is electrolysed feed liquid evaporation concentration system | |
| CN206033271U (en) | High -purity poly aluminium chloride production system | |
| US20130062566A1 (en) | Method of Recovering and Concentrating an Aqueous N-methylmorpholine-N-Oxide (NMMO) Solution | |
| CN206940777U (en) | A kind of production equipment of ton polyphenylene oxide | |
| CN219964416U (en) | Recovery system for ammonia fixed in condensate of ammonia still | |
| CN207143154U (en) | Acetone, the retracting device of diphenyl sulphone (DPS) in a kind of polyether-ether-ketone production process | |
| CN111004393A (en) | Washing water circulation process for polyphenylene sulfide production | |
| CN221579727U (en) | Electronic aluminum foil waste sulfuric acid low-temperature normal-pressure evaporation crystallization recovery device | |
| CN115350500B (en) | Byproduct comprehensive utilization system in foaming agent production | |
| CN114452669B (en) | Reclaimed material liquid rectifying and purifying system containing NMP | |
| CN220989729U (en) | Clear solution crystallization system of sodium chloride | |
| CN103086902B (en) | Method of recovering ammonia gas for production of glycine through alcohol phase system | |
| CN220736235U (en) | Evaporation system with wet vacuum suction device for urea production | |
| CN213762349U (en) | A solid-liquid separation equipment for sodium methoxide production | |
| CN113527086A (en) | Method for reducing residue generation amount in sodium hydrosulfite production process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |