CN109320764B - Industrialized pure PU foam alcoholysis recovery method and special recovery feeding device - Google Patents
Industrialized pure PU foam alcoholysis recovery method and special recovery feeding device Download PDFInfo
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- 229920005830 Polyurethane Foam Polymers 0.000 title claims abstract description 90
- 238000006136 alcoholysis reaction Methods 0.000 title claims abstract description 48
- 238000011084 recovery Methods 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000006243 chemical reaction Methods 0.000 claims abstract description 84
- 229920005862 polyol Polymers 0.000 claims abstract description 60
- 150000003077 polyols Chemical class 0.000 claims abstract description 60
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 28
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 19
- 239000003054 catalyst Substances 0.000 claims abstract description 13
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 13
- 235000010299 hexamethylene tetramine Nutrition 0.000 claims abstract description 12
- 239000004312 hexamethylene tetramine Substances 0.000 claims abstract description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims description 15
- 238000004064 recycling Methods 0.000 claims description 15
- 239000000126 substance Substances 0.000 claims description 15
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 12
- 238000001816 cooling Methods 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 11
- 238000005303 weighing Methods 0.000 claims description 11
- IMNIMPAHZVJRPE-UHFFFAOYSA-N triethylenediamine Chemical compound C1CN2CCN1CC2 IMNIMPAHZVJRPE-UHFFFAOYSA-N 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 9
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 229910001220 stainless steel Inorganic materials 0.000 claims description 7
- 239000010935 stainless steel Substances 0.000 claims description 7
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 6
- 229940068918 polyethylene glycol 400 Drugs 0.000 claims description 5
- 238000009833 condensation Methods 0.000 claims description 4
- 230000005494 condensation Effects 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000010992 reflux Methods 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 4
- 239000004809 Teflon Substances 0.000 claims description 3
- 229920006362 Teflon® Polymers 0.000 claims description 3
- 239000011247 coating layer Substances 0.000 claims description 3
- SZXQTJUDPRGNJN-UHFFFAOYSA-N dipropylene glycol Chemical compound OCCCOCCCO SZXQTJUDPRGNJN-UHFFFAOYSA-N 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 3
- 239000003638 chemical reducing agent Substances 0.000 claims 1
- 239000012855 volatile organic compound Substances 0.000 description 17
- 239000002699 waste material Substances 0.000 description 13
- 239000004814 polyurethane Substances 0.000 description 12
- 229960004011 methenamine Drugs 0.000 description 8
- 238000012360 testing method Methods 0.000 description 8
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 7
- 238000001514 detection method Methods 0.000 description 5
- 238000005187 foaming Methods 0.000 description 5
- 238000007789 sealing Methods 0.000 description 4
- 150000005846 sugar alcohols Polymers 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 229920002635 polyurethane Polymers 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- -1 polytetrafluoroethylene Polymers 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 150000004982 aromatic amines Chemical class 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000011496 polyurethane foam Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
- C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
- C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
- C08J11/24—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds containing hydroxyl groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
- C08J2375/04—Polyurethanes
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/584—Recycling of catalysts
-
- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
The invention discloses an industrialized pure PU foam alcoholysis recovery method and a special recovery feeding device, which are characterized in that the recovery feeding device comprises a reaction kettle, a pneumatic gate valve, a feeding reducing elbow, a main feeding screw conveyor, an auxiliary feeding double-screw feeding conveyor, a feeding hopper, a flexible connection and catalyst, hexamethylenetetramine, hydrogen peroxide and other small material feeding devices; the alcoholysis recovery method comprises the steps of feeding, alcoholysis and recovery; the method has the advantages of high feeding speed and accurate feeding, ensures that the mass ratio of the pure PU foam feeding quality and the added main recycled alcoholysis agent is stable, and ensures that the catalyst, the hexamethylenetetramine and the hydrogen peroxide can be timely added into a reaction system according to the process requirements, thereby ensuring that each control index of each batch of recycled polyol is stable.
Description
The technical field is as follows:
the invention relates to the technical field of alcoholysis recovery of pure PU foam waste leftover materials, in particular to an industrialized pure PU foam alcoholysis recovery method and a special recovery feeding device thereof; the method can improve the feeding speed of pure PU foam required by alcoholysis reaction and reduce VOC index of recycled polyol.
Background art:
in the production process of PU products such as automobile interior ceilings, refrigerators, refrigeration house heat preservation, building external wall heat preservation and the like, a large amount of PU foam corner waste materials can be generated, and the disposal problem of the waste materials is not well solved all the time.
The PU foam leftover bits and pieces have small density and large occupied area, and are difficult to naturally decompose under the conditions of normal temperature and normal pressure. The common treatment methods at present include landfill, incineration and physical pulverization and re-bonding recovery. The waste is treated by adopting a landfill method, so that no value is generated and land resources are wasted; the incineration method is adopted for treatment, although a certain amount of energy can be recovered, air pollution can be caused; the physical crushing and PU glue re-bonding method is adopted for treatment, only low-grade products can be produced, large-scale industrial production is difficult, and the application of the method is limited.
In recent years, the problem of environmental protection is more and more emphasized, the country strongly advocates a green circular economy production mode, the law enforcement of environmental protection is enhanced, and the relevant environmental protection regulations are more and more strict. The pure PU waste materials treated by adopting a landfill, incineration or physical method can not meet the development requirement of green circular economy more and more, so the method for recovering the pure PU waste materials by improving the chemical method is further emphasized.
At present, the chemical recovery method of pure PU foam waste which is researched more in industry is an alcoholysis method, and the difficulty of the alcoholysis recovery process of pure PU foam is that the pure PU foam has low density, one-time recovery production needs to divide dozens of cubic meters of pure PU foam into dozens of times to be added into a reaction kettle, and the pure PU foam crushed aggregates are difficult to be smoothly conveyed into the reaction kettle by a common screw machine. The reason is that after the temperature of the reaction kettle rises, the alcoholysis agent volatilizes to enable PU foam crushed aggregates to expand and become sticky, so that PU foam with lower density is adhered to a feeding pipeline or a soft connector to further influence the feeding speed, and the problem of good pure PU foam feeding is the key for PU foaming processing enterprises to carry out recovery work. In addition, the polyol recovered by the common method has a problem of large odor, and even if the VOC index of the recovered polyol cannot be effectively reduced, the VOC index of the used polyol is strictly controlled by many products, so that the application range of the recovered polyol is limited. Therefore, the VOC index of the pure PU foam waste leftover material for recycling the polyol is effectively reduced, and the key for successfully recycling the pure PU foam waste material is realized. Chinese patent CN101845152A discloses that one method for purifying the resulting alcoholysis product by distillation under reduced pressure is a laboratory-only experiment; chinese patent CN103694447A discloses a method for depolymerizing waste polyurethane with ethylene glycol and preparing flame retardant polyurethane foam, chinese patent CN103275349A discloses a method for recovering polyol by solvent extraction, chinese patent CN102796279A discloses a method for recovering polyurethane by alcoholysis, chinese patent CN104672414A discloses a method for preparing heat insulation material from recovered waste elastomer, and chinese patent CN102432915A discloses a method for regenerating polyol by depolymerizing waste polyurethane with microwave; none of these patents describe how to speed up the feed and reduce the odor of the recycled polyol in the commercial production of pure PU foams. Therefore, the method for solving the problems of quick feeding of pure PU foam and reduction of VOC (volatile organic compound) odor of the recycled polyol plays an important role in expanding the application field of the recycled polyol.
The invention content is as follows:
the invention aims to overcome the defects of the prior art and provide an industrialized pure PU foam alcoholysis recovery method.
Another object of the present invention is to provide a recycling and feeding device for alcoholysis of industrial pure PU foam.
The invention mainly solves the problems that the existing industrialized pure PU foam is slow in recovery and feeding, the VOC index of the polyalcohol is high and the like.
The technical scheme of the invention is as follows: an industrialized pure PU foam alcoholysis recovery method is characterized in that a special recovery feeding device is adopted, and the alcoholysis recovery method comprises the following process steps:
a, introducing dry nitrogen to exhaust air in a reaction kettle, adding a main alcoholysis agent and a catalyst into the reaction kettle, wherein the addition amount of the catalyst accounts for 0.1-0.12% of the total mass of the recovered polyol; weighing pure PU foam crushed aggregates needing to be recycled through a weighing bin, and conveying the pure PU foam crushed aggregates into a feeding hopper connected with a flexible connector through a screw conveyor;
b, extruding pure PU foam crushed aggregates temporarily stored in a feeding hopper into the main feeding screw conveyor through a plurality of rows of spirally arranged feeding teeth in a relatively rotating manner by an auxiliary feeding double-spiral feeding conveyor which operates later than the screw conveyor;
c, the main feeding screw conveyer pushes the extruded pure PU foam crushed aggregates into a feeding reducing elbow, and the diameter of the interface of the feeding reducing elbow and the main feeding screw conveyer is smaller than that of the interface of the feeding reducing elbow and the pneumatic gate valve; then PU foam crushed aggregates rapidly enter a feeding hole of a pneumatic gate valve which is opened simultaneously;
d, rapidly feeding the pure PU foam crushed aggregates into the reaction kettle through a feeding hole in a movable valve core of the pneumatic gate valve to finish the feeding process of the pure PU foam crushed aggregates at one time; adding pure PU foam crushed aggregates into the polyol by times, and correspondingly adding hexamethylenetetramine into the polyol by times through a small-aggregate feeding device, wherein the total mass of the hexamethylenetetramine added accounts for 0.13-0.15% of the total mass of the recycled polyol; after the feeding is finished each time, the movable valve core of the pneumatic gate valve is quickly reset, the movable valve core part without the feeding hole is communicated with the reaction kettle in a sealed way, and the polyol steam in the reaction kettle is prevented from overflowing;
e, adding the pure PU foam crushed aggregates and the main alcoholysis agent in a mass ratio of 46-48: 54-52; after the pure PU foam crushed aggregates are fed, carrying out recovery reaction at the temperature of 160-190 ℃ until all pure PU foam in the reaction kettle is completely alcoholyzed;
and f, after alcoholysis is completed, cooling the inside of the reaction kettle to 70-75 ℃, adding hydrogen peroxide into the reaction kettle once through the bottom of the small material feeding device, wherein the adding amount of the hydrogen peroxide is 0.40-0.43% of the total mass of the recovered polyol, continuously stirring for reaction for 1 hour, completely reacting aldehyde substances in the recovered polyol, heating the reaction kettle to 115-125 ℃, controlling the outlet temperature of the condensation reflux device and the water separation device to be 105-110 ℃, continuously stirring by a stirrer of the reaction kettle, removing generated water for about 1 hour under the drive of dry nitrogen until the water content of the recovered polyol is below 0.1%, cooling to 80-90 ℃, filtering by a 60-mesh stainless steel filter screen, discharging, and finishing the primary polyol recovery production process.
Further, the main alcoholysis agent in the step a is one or a mixture of two or more of ethylene glycol, 1, 4-butanediol, diethylene glycol, dipropylene glycol and polyethylene glycol 400.
Further, the catalyst in the step a is prepared from t-12 and triethylene diamine.
The invention relates to a special recovery feeding device for alcoholysis of industrial pure PU foam, which comprises a weighing bin and a screw conveyor, wherein the weighing bin and the screw conveyor are connected; the device is characterized in that the screw conveyor is connected with a feeding funnel through a flexible connection 7, an auxiliary feeding double-helix feeding conveyor is arranged below the feeding funnel and connected with a main feeding screw conveyor, the main feeding screw conveyor is connected with a feeding reducing elbow, and the feeding reducing elbow is communicated with a reaction kettle through a pneumatic gate valve; and the reaction kettle is provided with a small material feeding device.
Furthermore, the auxiliary feeding double-screw feeding conveyor runs later than the screw conveyor.
Furthermore, the diameter of the interface between the feeding reducing elbow and the main feeding screw conveyor is smaller than that of the interface between the feeding reducing elbow and the pneumatic gate valve.
Furthermore, the inner wall of the feeding reducing elbow is polished and sprayed with a Teflon coating layer, and the surface energy of the inner wall is lower than 20 dyn/cm.
Furthermore, the pneumatic gate valve is connected with the reaction kettle by a flange.
Furthermore, a polytetrafluoroethylene sealing gasket is used for self-lubricating sealing between the movable valve core and the fixed valve shell of the pneumatic gate valve.
Furthermore, the small material feeding device consists of a feeding hopper, a valve and a pipeline.
The comparative tests were as follows:
comparing 1, selecting a 3-ton reaction kettle, wherein under the existing feeding condition, a pneumatic gate valve, a feeding reducing elbow, a main feeding screw conveyor, an auxiliary feeding double-screw feeding conveyor and a feeding hopper are not arranged, PU foam crushed aggregate weighing bins are only used for feeding the screw conveyor to the feeding hopper of the reaction kettle, the screw conveyor is directly communicated to a phi 300 pneumatic butterfly valve through flexible connection, and the feeding speed can reach 5KG/min at most, and sometimes the feeding is influenced by the blockage of the pneumatic butterfly valve; only the pure PU foam particles required are fed into the reaction kettle for more than 3 hours; and (3) feeding pure PU foam crushed aggregates, reacting for 2 hours, cooling to 80-90 ℃, and filtering by a stainless steel filter screen of 60 meshes to obtain a tan recovered product. The detection shows that the hydroxyl value is 390mgKOH/g, the water content is 0.096%, the recycled polyol is added into a foaming system in proportion, and the obtained PU plate has the following odor VOC detection:
compared with the control 1, under the same other conditions, the feeding time of each polyol recovery is shortened from 3h to 1h under the same conditions only because of different feeding devices of the reaction kettle; under the same long-time condition, the feeding efficiency of pure PU foam crushed aggregates is improved by more than 3 times; as the pure PU foam crushing efficiency is improved in the test 1, the reaction time is relatively prolonged, the moisture content index is obviously reduced by about 12 percent, but the hydroxyl value index and the important odor index of the recycled polyol are not obviously improved, and therefore, the process production needs to be continuously improved.
comparing 2, under the condition that a small material feeding device 8 of the reaction kettle is not used, adding a catalyst into the reaction kettle along with a main alcoholysis agent at one time, adding no hexamethylenetetramine and hydrogen peroxide, continuously reacting for 2 hours at constant temperature after adding pure PU foam crushed aggregates at the last time, delaying the reaction for 2 hours, cooling to 80-90 ℃, testing the polyol recovered after filtering through a 60-mesh stainless steel net, wherein the hydroxyl value is 398mgKOH/g, the water content is 0.087%, adding the recovered polyol into a foaming system according to the proportion, and detecting the VOC of the obtained PU plate by using the recovered polyol:
through comparison between the experiment 2 and the comparison 2, feeding is carried out under the condition that a special device for a pure PU foam alcoholysis recovery reaction kettle is arranged, and through improvement of a recovery process, in a recovery process (5 h) which is basically the same for a long time, aldehyde substances in the recovered polyol are basically reacted, the hydroxyl value index is reduced by about 18%, and the comparison of an odor VOC project is obviously improved; the odor is reduced by 0.5 grade according to the public standard, and the odor is reduced by 1 grade according to the Jili standard; and the reduction of the VOC index content of the recycled polyol is the key for successfully recycling the pure PU foam waste leftover material.
Compared with the water content of the control 1, the water content of the recovered polyol is obviously reduced by 9-12% by comparing the water content of the test 1 and the test 2, which indicates that the pure PU foam is fed quickly for reaction, and the recovered polyol is dehydrated for a longer time to help reduce the water content; the invention improves the quality of the recycled polyol and enlarges the application range of the recycled polyol.
Through comparison of tests and controls, the recovery and feeding device and the recovery process provided by the invention can be used for recovering and producing pure PU foam, and the quality of the obtained recovered polyol is obviously improved.
Compared with the prior art, the industrialized pure PU foam alcoholysis recovery method and the special recovery feeding device thereof have prominent substantive characteristics and remarkable progress: 1. in the PU foam feeding process, hexamethylenetetramine is added from a small material feeding device of a reaction kettle, aromatic amine generated in the polyol recovery reaction process is converted into aldehyde substances and ammonia gas, the ammonia gas is discharged out of the reaction system along with nitrogen gas, and the aldehyde substances are required to be further treated; 2. after the recovery reaction of the polyhydric alcohol is finished, adding hydrogen peroxide into the reaction kettle through a small material feeding device at a certain temperature, reacting with the aldehyde substance, oxidizing the aldehyde substance into an acid substance, and generating an ester substance from the acid substance and the alcohol substance, so that the hydroxyl value of the alcohol substance is reduced, and the VOC index of the recovered polyhydric alcohol is reduced; 3. the feeding device of the invention improves the feeding speed by about 3 times; meanwhile, in the same long reaction time, the dehydration time is prolonged, the water content of the recycled polyol is reduced, and the quality of the recycled polyol is obviously improved; because the feeding is accurate, the stable mass ratio of the pure PU foam feeding quality and the added main recycled alcoholysis agent is ensured, and the catalyst, the hexamethylenetetramine and the hydrogen peroxide can be timely added into a reaction system according to the process requirement, thereby ensuring the stability of each control index of each batch of recycled polyol; 4. the pure PU foam feeding mode is combined with the recovery process, and the recovered polyol with stable performance and relatively low water content and VOC (volatile organic compound) indexes can be produced; 5. the pure PU foam is quick to recover and feed, the efficiency is improved, and the cost is reduced.
Description of the drawings:
FIG. 1 is a schematic view of a recycling feeding apparatus;
FIG. 2 is a front view of a reactor feed system;
fig. 3 is a side view of a portion of the feed system of fig. 2.
1 a reaction kettle 2, a pneumatic gate valve 3, a feeding reducing elbow 4, a main feeding screw conveyer 5, an auxiliary feeding double-screw feeding conveyer 6, a feeding hopper 7, a weighing bin 9, a small material feeding device 9 and a screw conveyer 10.
The specific implementation mode is as follows:
for a better understanding and appreciation of the invention, specific embodiments thereof are described in detail below with reference to the accompanying drawings.
In the embodiment 1, referring to fig. 1, 2 and 3, according to design requirements, a weighing bin 9 and a screw conveyor 10 with proper specifications are selected, and are conventional devices and are connected; connecting a screw conveyor 10 with a feeding funnel 6 through a flexible connection 7, installing an auxiliary feeding double-helix feeding conveyor 5 at the lower end of the feeding funnel 6, wherein the auxiliary feeding double-helix feeding conveyor 5 operates more slowly than the screw conveyor 10; connecting an auxiliary feeding double-helix feeding conveyor 5 with a main feeding screw conveyor 4, connecting the main feeding screw conveyor 4 with a feeding reducing elbow 3, wherein the diameter of the interface of the main feeding screw conveyor 4 and the feeding reducing elbow 3 is phi 200, polishing the inner wall of the feeding reducing elbow 3, spraying a Teflon coating layer, and the surface energy of the inner wall is lower than 20 dyn/cm; communicating and connecting a feeding reducing elbow 3 with a reaction kettle 1 through a pneumatic gate valve 2, reducing the interface of the feeding reducing elbow 3 and the pneumatic gate valve 2 into phi 300, connecting the pneumatic gate valve 2 with the reaction kettle 1 through a flange, and self-lubricating and sealing a movable valve core and a fixed valve shell of the pneumatic gate valve 2 through a polytetrafluoroethylene sealing gasket; a small material feeding device 8 is arranged on the reaction kettle 1, and the small material feeding device 8 consists of a feeding funnel, a valve and a pipeline; the special recovery and feeding device for the alcoholysis of the industrial pure PU foam is formed.
By adopting the special recycling and feeding device of the embodiment 1, the alcoholysis recycling method comprises the following process steps:
a, introducing dry nitrogen to exhaust air in a reaction kettle 1, adding a main alcoholysis agent and a catalyst into the reaction kettle 1, wherein the addition amount of the catalyst accounts for 0.1-0.12% of the total mass of the recovered polyol; pure PU foam crushed aggregates (with the diameter of about 30 mm) to be recycled are weighed by a weighing bin 9, and then are conveyed into a feeding hopper 6 connected with a flexible connector 7 by a screw conveyor 10; the main alcoholysis agent is one or the mixture of two or more of ethylene glycol, 1, 4-butanediol, diethylene glycol, dipropylene glycol and polyethylene glycol 400; the catalyst is prepared from t-12 and triethylene diamine;
b, relatively rotating and extruding pure PU foam crushed aggregates temporarily stored in a loose state in a feeding hopper 6 by an auxiliary feeding double-spiral feeding conveyor 5 which operates later than the screw conveyor 10 into the main feeding screw conveyor 4 through a plurality of rows of spirally arranged feeding teeth (the tooth space and the top end are both larger than 30mm, and the tooth end with the tooth length of 100mm has radian to prevent the pure PU foam crushed aggregates from being hung upside down);
c, the main feeding screw conveyor 4 pushes the extruded pure PU foam crushed aggregates into the feeding reducing elbow 3 to push the resistance of the pure PU foam in the reducing elbow 3 to be gradually reduced (the resistance is gradually reduced due to the gradually increased inner diameter of the elbow, so that the PU foam crushed aggregates can enter the reaction kettle) to rapidly enter the feeding hole of the pneumatic gate valve 2 which is opened at the same time;
d, rapidly feeding the pure PU foam crushed aggregates into the reaction kettle 1 through a feeding hole on a movable valve core of the pneumatic gate valve 2 to finish the feeding process of the pure PU foam crushed aggregates at one time; pure PU foam crushed aggregates are added in a plurality of times, and hexamethylene tetramine is correspondingly added in a plurality of times through a small material feeding device 8 of a reaction kettle, wherein the total adding amount of the hexamethylene tetramine accounts for 0.13-0.15% of the total mass of the recycled polyol; after the feeding is finished each time, the movable valve core of the pneumatic gate valve 2 is quickly reset, the part of the movable valve core without the feeding hole is communicated with the reaction kettle 1 and is sealed, and the polyol steam in the reaction kettle 1 is prevented from overflowing;
e, the mass ratio of the addition amount of the pure PU foam crushed aggregates to the addition amount of the main alcoholysis agent is 46-48: 54-52; carrying out recovery reaction at 160-190 ℃ until all pure PU foam in the reaction kettle 1 is completely alcoholyzed; and f, after alcoholysis is completed, cooling the inside of the reaction kettle to 70-75 ℃, adding hydrogen peroxide (with the hydrogen peroxide content of 30%) into the reaction kettle at one time from the bottom of a small material feeding device 8 of the reaction kettle, wherein the adding amount of the hydrogen peroxide is 0.40-0.43% of the total mass of the recovered polyol, continuously stirring for reaction for 1 hour, completely reacting aldehyde substances in the recovered polyol, heating the reaction kettle to 115-125 ℃, controlling the outlet temperature of a condensation reflux device and a moisture separation device to be 105-110 ℃, continuously stirring by a stirrer of the reaction kettle, removing the generated moisture for 1 hour under the drive of dry nitrogen until the moisture content of the recovered polyol is detected to be below 0.1%, cooling to 80-90 ℃, filtering by a 60-mesh stainless steel filter screen, and discharging to finish the primary polyol recovery production process.
The above-described embodiments are intended to be illustrative only and not to limit the scope of the invention, and various changes or modifications may be made therein by those skilled in the art after learning the content of the present invention, which equivalents are also within the scope of the invention as defined in the appended claims.
Claims (10)
1. An industrialized pure PU foam alcoholysis recovery method is characterized in that a recovery feeding device is adopted, and the alcoholysis recovery method comprises the following process steps:
a, introducing dry nitrogen to exhaust air in a reaction kettle, adding a main alcoholysis agent and a catalyst into the reaction kettle, wherein the addition amount of the catalyst accounts for 0.1-0.12% of the total mass of the recovered polyol; weighing pure PU foam crushed aggregates needing to be recycled through a weighing bin, and conveying the pure PU foam crushed aggregates into a feeding hopper connected with a flexible connector through a screw conveyor;
b, extruding pure PU foam crushed aggregates temporarily stored in a feeding hopper into the main feeding screw conveyor through a plurality of rows of spirally arranged feeding teeth in a relatively rotating manner by an auxiliary feeding double-spiral feeding conveyor which operates later than the screw conveyor;
c, the main feeding screw conveyer pushes the extruded pure PU foam crushed aggregates into a feeding reducing elbow, and the diameter of the interface of the feeding reducing elbow and the main feeding screw conveyer is smaller than that of the interface of the feeding reducing elbow and the pneumatic gate valve; then PU foam crushed aggregates rapidly enter a feeding hole of a pneumatic gate valve which is opened simultaneously;
d, rapidly feeding the pure PU foam crushed aggregates into the reaction kettle through a feeding hole in a movable valve core of the pneumatic gate valve to finish the feeding process of the pure PU foam crushed aggregates at one time; adding pure PU foam crushed aggregates into the polyol by times, and correspondingly adding hexamethylenetetramine into the polyol by times through a small-aggregate feeding device, wherein the total mass of the hexamethylenetetramine added accounts for 0.13-0.15% of the total mass of the recycled polyol; after the feeding is finished each time, the movable valve core of the pneumatic gate valve is quickly reset, the movable valve core part without the feeding hole is communicated with the reaction kettle in a sealed way, and the polyol steam in the reaction kettle is prevented from overflowing;
e, adding the pure PU foam crushed aggregates and the main alcoholysis agent in a mass ratio of 46-48: 54-52; after the pure PU foam crushed aggregates are fed, carrying out recovery reaction at the temperature of 160-190 ℃ until all pure PU foam in the reaction kettle is completely alcoholyzed;
and f, after alcoholysis is completed, cooling the inside of the reaction kettle to 70-75 ℃, adding hydrogen peroxide into the reaction kettle once through the bottom of the small material feeding device, wherein the adding amount of the hydrogen peroxide is 0.40-0.43% of the total mass of the recovered polyol, continuously stirring for reaction for 1 hour, completely reacting aldehyde substances in the recovered polyol, heating the reaction kettle to 115-125 ℃, controlling the outlet temperature of the condensation reflux device and the water separation device to be 105-110 ℃, continuously stirring by a stirrer of the reaction kettle, removing generated water for 1 hour under the drive of dry nitrogen until the water content of the recovered polyol is below 0.1%, cooling to 80-90 ℃, filtering by a 60-mesh stainless steel filter screen, discharging, and finishing the primary polyol recovery production process.
2. The alcoholysis recovery method of claim 1, wherein the main alcoholysis agent in step a is one or a mixture of two or more of ethylene glycol, 1, 4-butanediol, diethylene glycol, dipropylene glycol and polyethylene glycol 400.
3. The alcoholysis recovery process of claim 1, wherein the catalyst in step a is prepared from t-12 triethylenediamine.
4. The recycling and feeding device for realizing the alcoholysis recycling method of industrial pure PU foam as claimed in claim 1, 2 or 3, comprising a weighing bin (9) and a screw conveyor (10) which are connected; the device is characterized in that the screw conveyor (10) is connected with a feeding hopper (6) through a flexible connection (7), an auxiliary feeding double-helix feeding conveyor (5) is arranged below the feeding hopper (6), the auxiliary feeding double-helix feeding conveyor (5) is connected with a main feeding screw conveyor (4), the main feeding screw conveyor (4) is connected with a feeding reducing elbow (3), and the feeding reducing elbow (3) is communicated and connected with the reaction kettle (1) through a pneumatic gate valve (2); and a small material feeding device (8) is arranged on the reaction kettle (1).
5. A recycling and feeding device for alcoholysis of industrial pure PU foam according to claim 4, wherein said auxiliary feeding double screw feeding conveyor (5) is operated at a delay from the screw conveyor (10).
6. The recycling and feeding device for alcoholysis of industrial pure PU foam according to claim 4, wherein the diameter of the interface between the feeding reducing elbow (3) and the main feeding screw conveyor (4) is smaller than the diameter of the interface between the feeding reducing elbow (3) and the pneumatic gate valve (2).
7. The recycling and feeding device for alcoholysis of industrial pure PU foam according to claim 4 or 6, wherein the inner wall of the feeding reducer elbow (3) is polished and coated with Teflon coating layer, and the surface energy of the inner wall is lower than 20 dyn/cm.
8. A recycling and feeding device for alcoholysis of industrial pure PU foam according to claim 4, wherein said pneumatic gate valve (2) is connected to said reaction vessel (1) by flange.
9. The recycling and feeding device for alcoholysis of industrial pure PU foam according to claim 4, 6 or 8, wherein the movable valve core and the fixed valve shell of the pneumatic gate valve (2) are sealed by self-lubricating PTFE gasket.
10. A recycling and feeding device for alcoholysis of industrial pure PU foam according to claim 4, wherein said small material feeding device (8) comprises of feeding hopper, valve and pipe.
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| US6660236B1 (en) * | 1998-11-30 | 2003-12-09 | Takeda Chemical Industries, Ltd. | Apparatus for decomposition and recovery of polyurethane resin |
| CN102618010A (en) * | 2012-03-08 | 2012-08-01 | 广州聚天化工科技有限公司 | Continuous production device and method for regenerating polyol by depolymerizing waste polyurethane |
| CN105399985A (en) * | 2015-12-14 | 2016-03-16 | 浙江华江科技股份有限公司 | Polyurethane foam chemical recovery method |
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| US6660236B1 (en) * | 1998-11-30 | 2003-12-09 | Takeda Chemical Industries, Ltd. | Apparatus for decomposition and recovery of polyurethane resin |
| CN102618010A (en) * | 2012-03-08 | 2012-08-01 | 广州聚天化工科技有限公司 | Continuous production device and method for regenerating polyol by depolymerizing waste polyurethane |
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Denomination of invention: Industrial pure PU foam alcoholysis recovery method and special recovery feeding device Effective date of registration: 20211112 Granted publication date: 20210406 Pledgee: Yantai Fushan huiran Private Capital Management Co.,Ltd. Pledgor: YANTAI ZHENGHAI HIGH TECHNOLOGY CO.,LTD. Registration number: Y2021980012308 |
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Date of cancellation: 20220505 Granted publication date: 20210406 Pledgee: Yantai Fushan huiran Private Capital Management Co.,Ltd. Pledgor: YANTAI ZHENGHAI HIGH TECHNOLOGY CO.,LTD. Registration number: Y2021980012308 |