RU2683746C1 - Method and apparatus for regeneration of rubber-containing wastes - Google Patents

Abstract

FIELD: waste processing and disposal.SUBSTANCE: invention relates to processing and methods for recovery of rubber wastes of rubber-technical production, as well as rubber-containing wastes in form of crumbs, borings and chips. Method of regeneration includes preparation of modifier and its mixing with regenerated material. Regenerated material is used in form of crumbs, borings, chips. Modifier for passenger car tires represents a mixture of urea powder and oxalic acid powder in ratio of 52:48 wt%. Modifier is fed in two stages. At first step modifier in amount of not more than 45–50 wt% of required design mass is introduced into mixer, where it is mixed with portion of material for 2.0–2.5 minutes. Said portion of material is fed into nutritional device and 1-2 passes of portion through rollers. At the second stage, 55–50 wt% of the required modifier are added to the regenerated portion of the nutrient in the nutritional device and mixed for 2.0–2.5 minutes. 5-6 passes of material portion are performed through rollers, reducing clearance between rolls by 0.3–0.4 mm after each pass. Obtained regenerate in the form of spongy crumbs or thin sheets is fed into the finished product storage. Plant for regeneration includes mixing rollers, nutrient device with distributor and slit nozzle, separation barrier. To move along guides barrier is equipped with drive.EFFECT: invention allows to enhance the end product quality, completely preserve the composition of the initial rubber wastes, reduce power consumption and prime cost of processing.7 cl, 5 dwg

Description

1. Introduction. The method and installation are intended for the regeneration (devulcanization) of rubber wastes from rubber industries, as well as rubber-containing wastes, in particular crumbs, shavings and chips obtained after processing of old vehicle tires. Regeneration is carried out in mixing rollers using a powder modifier. The essence of the regeneration method is that the powder modifier is introduced into a portion of the processed waste in two stages. At the first stage, not more than 45-50% (weight units) of the calculated portion of the modifier are fed into the mixer, where they are mixed for 2.0-2.5 minutes. One or two passes of the material through the rollers are carried out. The second stage includes the accumulation of regenerated material in the nutrient device and the supply to the nutrient device of 55-50% (weight units) of the remaining portion of the modifier. Mix the material with the modifier for 2.0-2.5 minutes.

For 5-6 passes, the regenerated material is passed through the rollers, reducing the gap between the rollers by 0.3 ... 0.4 mm after each pass.

The installation contains mixing rollers equipped with a regulator of the gap between the rollers. A nutrient device is located above the rollers, and a regenerative rubber waste distributor is located under the rollers. The distributor is equipped with a rotary mechanism. To ensure multiple passage of the regenerated material through the rollers, the installation is equipped with a conveyor system. The installation includes: a bunker-accumulator of rubber waste combined with a weight batcher, a container for a modifier with a batcher, a mixer. Ready regenerate is accumulated in the storage tank.

The conveyor system includes: a conveyor for feeding rubber crumbs and chips for processing, a return and intermediate conveyor, a conveyor for the removal of finished products. A separation barrier is installed between the return conveyor and the conveyor for the outlet of finished products. A magnetic separator is installed above the conveyor for feeding chips and chips for processing to separate particles of steel wire, if pieces of steel cord are possible in the rubber crumb.

The filing of the modifier in the mixing device and the feeder is carried out using a pneumatic ejector through a 3-way shutter.

The proposed method and installation are adapted for ozone and ozone-cryogenic technology for processing rubber waste and rubber-containing waste from the recycling of old vehicle tires.

2. Scope

The proposed installation can be used at enterprises for the processing of used tires of vehicles, as well as in industry for the production of rubber products for technical and domestic purposes. The most promising is the use of the installation in technological schemes for processing tires by the method of sequential treatment with gas containing ozone and cryogenic treatment. The installation can be used for the regeneration of rubber waste.

3. Existing analogues

There are various technological schemes and installations for the regeneration (devulcanization) of rubber-containing waste. Various substances are used in the regeneration processes: emollients, activators, modifiers, emulsifiers and others. The most widely used thermomechanical and chemical technologies for regeneration. Also known are technologies using water-neutral and microwave processing, sonication and biological regeneration methods. As a rule, all technological systems use combinations of chemical and thermomechanical methods of regeneration, which are adjusted to a certain type of modifier. Activators or softeners are introduced into the modifier depending on the type of waste being processed and the method of regeneration.

For thermomechanical and chemical regeneration methods, mainly worm machines and much less often mixing rollers are used.

Technological installation for the regeneration of rubber-containing waste by the water-neutral method [Bobovich BB Recycling industrial waste. Textbook for high schools. // M.: SPIntermet Engineering. 1999. 445 pp.] Contains: a crushed rubber hopper, a softener container, batchers, an autoclave, a buffer tank, a mesh drum, a squeezing machine, regenerative mixing rollers and refining rollers. The disadvantages of this installation include:

- the process of devulcanization is carried out in two stages;

- the duration of the first stage (treatment with emollients) is 1.0-1.5 hours at a temperature of about 100 ° C. The process of devulcanization continues for 4-5 hours at a temperature of 180 ± 5 ° C and the pressure in the autoclave 1.1 ± 0.1 MPa;

- if there is textile cord in the waste, the process of devulcanization lasts 5-8 hours;

- the presence of two types of rollers, a mesh drum and a squeezing machine increases the cost of hardware manufacturing of the installation, and the process is difficult to automate.

The recovery of rubber-containing waste is carried out mainly by the thermomechanical method. To do this, use various schemes of technological installations. Typically, such installations contain: a rubber crumb hopper, a softener container, dispensers, a mixer where a modifier, a worm devulcanizer and refining rollers are introduced ["BF Goodrich Company" (USA), "Toyoda Gosei" (Japan) and others]. The disadvantages of such installations are:

- stringent requirements for the cleanliness and size of the processed rubber crumb (size not more than 0.8 mm and the content of textile fibers not more than 5% (by weight);

- to create the required efforts of the screw, a large amount of electrical energy is consumed on the drive of the extruder (devulcanizer);

- high temperature of the product (should not exceed 190 ° C), which leaves the screw head, which requires subsequent cooling of the regenerate;

- a more complex technological scheme, since it contains a grinder of initial waste and refining rollers.

The process for the recovery of rubber waste by the HSM method (High Shear Mixer) is used by REP International (France) and Watson Brown HSM Ltd. (Germany) [Wolf M. Devulcanization of rubbers and their introduction into new mixtures without deterioration. "Polymeric materials", No. 8, 2016, p. 14-18]. The essence of the HSM method is the selective cleavage of crosslinking sites in the material under the action of shear stresses. The method is based on the principles of mechanochemistry that under the influence of mechanical stresses, chemical changes of the processed substance occur. Before loading, the material is sorted by rubber waste and crushing. Waste processing must take place under strictly defined conditions and the process parameters must correspond to each type of material being processed. With all the seemingly positive aspects of the HSM method, it has several disadvantages:

- the complex design of the rotor and stator of the waste recycling machine, which makes its manufacture more expensive;

- very stringent requirements for the uniformity of the input material for processing and the size of the powders or granules;

- theoretically possible changes in the chemical nature of the substance, but given the complex prescription composition of car tires, it is almost impossible to obtain a completely devulcanized material.

Combinations of chemical and thermomechanical regeneration methods that are tailored to a specific type of modifier are used by the companies: American Rubber Technologies, Inc., BF Goodrich Company (USA), POLYMERight Inc. (Canada), "Toyoda Gosei" (Japan) and etc. These companies, as a rule, use a liquid modifier with the addition of activators, and a one-time passage of rubber crumb through a two or three-stage worm machine.

A common disadvantage of all technological systems is the strict requirements for the size of rubber crumb. Requirements for the small size of the feedstock leads to increased energy consumption for grinding rubber waste, chips, chips, as well as other preparatory operations. When mechanically grinding old tires or other products that contain textile and steel cord, it is almost impossible to get clean rubber waste. The separation of the remains of steel wire, especially from synthetic threads, is a lengthy and expensive process.

The closest technical solution is Patent US 6,831,109 B1, 12/2004 Beirakh et al. U.S. Cl. 521/41, 43.5, 40.5. According to the said patent, Levgum Ltd. (Israel), uses a powder modifier in its technology, and uses mixing rollers for machining rubber crumb. The operation of rubber crumb devulcanization is carried out by repeatedly passing crumbs through the mixing rollers. The use of the new modifier led to a reduction in the cost of processing by almost half compared to existing technologies. The developed modifier does not contain harmful components, does not emit hazardous waste or gases, that is, it is completely environmentally friendly. The regenerate retains its original composition of the feedstock: rubber waste. Crumbs from recycling used tires. The disadvantages of the installation and some technological parameters include:

- mandatory preliminary grinding of crumbs up to 0.5 mm, which complicates the adhesion of the powder modifier to such a small surface of the crumb when mixing the source material with a modifier;

- when carrying out devulcanization in a two-roll mill (rollers), about 20 passes through the gap between the rollers are required, which reduces the productivity of the installation as a whole;

- very stringent requirements for the gap between the rollers, which is 0.1-0.15 mm;

- low tangential speed of the fastest shaft, which is 0.5-0.7 m / s.

A small gap between the rolls leads to a sharp increase in the surface temperature of the rolls. This, in turn, raises the temperature of the regenerated material, from which vapors of the volatile components of the modifier can be released. This position affects the quality of the regenerate. To lower the surface temperature of the rolls, the rolls have a cavity through which water is pumped for cooling.

Known other methods and installations for the regeneration (devulcanization) of crumb rubber after the processing of worn-out tires and other rubber-containing waste, which are set forth in the patents:

Patent US 5,120,767; 6/1992 Allard et al. U.S. Cl. 521 / 40.5, 41, 45.5; 209/2, 38;

Patent US 5,275,948; 1/1994 Straube G. et al. U.S. Cl. 435/262; 241 / DIG.31; 264/349; 264/37;

Patent US 5,602,186; U.S. Cl. 521/41, 43; 208/89, 208;

US Patent 5,639,934; 6/1997 Yamasaki et al. U.S. Cl. 585/820, 241, 833, 853, 854; 208/213, 226;

US Patent 5,677,354; 11/1997 Oliveira Da Cunha Lima U.S. Cl. 521/41; 521 / 43.5; 521/42, 43; 521/413; 525/240;

Patent US 5,891,926; 4/1999 Hunt et al. U.S. Cl. 521/41, 44, 44.5, 49.5;

Patent US 5,955,035; 9/1999 Dinzburg et al. U.S. Cl. 422/128; 425/174; 425 / 174.2, 202;

Patent US 6,060,528; 5/2000 Wertz U.S. Cl. 521/40, 40.5, 41;

Patent US 6,387,965; 5/2002 Benko et al. U.S. Cl. 521/40, 40.5, 41, 43;

Patent US 6,387,966 B1; 5/2002 Goldshtein et al. U.S. Cl. 521/41, 43.5; 525/339, 368, 372, 386;

Patent US 6,541,526 B1; 4/2003 Goldshtein et al. U.S. Cl. 521/41, 43.5, 40.5;

Patent US 6,831,109 B1; 12/2004 Beirakh et al. U.S. Cl. 521/41, 43.5, 40.5;

Patent US 6,950,042 B1; 9/2005 Nakagawa et al. U.S. Cl. 525 / 336.6; 525 / 333.5, 333.6, 343, 353;

Patent US 7,032,847 B1; 4/2006 Debailleul U.S. Cl. 241/1, 23, 24.17, 65; 422/255;

Patent US 7,166,658 B2; 1/2007 Harrison et al. U.S. Cl. 523/307, 343; 521/41, 44, 45; 585/241;

Patent US 9,598,550 B2; 3/2017 Arnaud Daniel, U.S. Cl. 521/40, 41, 44.5, 45.5;

Patent MX 9803186, Int. Cl. C08J 11/00; C08J 11/10;

Patent DE 10052450; 4/2001 Krieg et al. Int. Cl. C08J / 00, 10; B29B 17/00;

Patent WO 2006056072, Int. Cl. C08J 11/10, 00;

Patent CZ 298755, Int. Cl. C08J 11/10, 18, 22, 28; C08C 19/08; C08L 17/00;

Patent RU 2098436; 10/1997 Babina et al. Int. Cl. C08L 17/00; C08K 3/06; C08L 95/00;

Patent RU 2130952; 5/1999 Gavrilenko et al. Int. Cl. C08J 11/00; C08L 17/00;

Patent RU 2145967; 2/2000 Prut et al. Int. Cl. C08J 11 / 04.10; C08K 5/17, 18;

Patent RU 2477729; 10/2012 Bondar et al. Cl. C08J 11/10; B29B 17/00; C08L 21/00

Other publications:

Bobovich B.B. Recycling industrial waste. Textbook for high schools. // M .: "SP Intermet Engineering". 1999.445 s.

Nekolyukin M.M. et al., Method for devulcanization of rubber crumb on roll equipment. // "Young Scientist" No. 12 (35), Volume 1, December, 2011, p. 34-36; Wolf M. Devulcanization of rubbers and their introduction into new mixtures without deterioration. "Polymer materials", No. 8, 2016, p. 14-18.

4. Design features and inventive novelty

In fig. 1 is a schematic flow diagram of an installation in which a powder modifier is used. The installation includes mixing rollers (1) with a drive (not shown in the diagram) and a regulator (2) of the gap between the rollers. Above the rollers, along their generators, a nutrient device (3) is installed. Under the rollers (1) there is a distributor (4), the casing of which has a V-shape. The separator (4) is equipped with a rotary mechanism (5). The barrier (6) is installed between the return conveyor (7) and the conveyor (8) of the outlet of the finished product. Intermediate conveyor (9) placed

between the conveyor (7) and the conveyor (10), from which the product for regeneration enters the feed device (3). A magnetic separator (11) is installed on the conveyor (10) for feeding chips and chips for processing to separate particles of steel wire, if there are possible pieces of steel cord in the rubber crumb. The crumb rubber, chips and chips are stored in the hopper (12). The storage hopper (12) is equipped with a weighing batcher (13), from where a portion of the starting material is fed into the mixer (14) using one of the known methods. The mixer (14) is equipped with a mixer (15).

The powder modifier is contained in a container (16), which is equipped with a dispenser (17).

The modifier is supplied from the tank (16) to the mixer (14) and the feed device (3) by a pneumatic conveying ejector (18) through a 3-way shutter (19) through the pipeline (20) and (21). The mixer (14) is equipped with an unloading shutter (22). Ready regenerate is accumulated in the accumulator (23).

In fig. 2 shows a schematic design of the nutrient device (3). The housing of the device (200) is made in a V-shape. A distributor (201) is placed inside the housing, which is made in the form of a screw, and the axis (202) of which is installed in the bushings (203) and (204). These bushings are mounted on the end walls (205) and (206) of the housing (200). The screw (201) is rotated by the drive (207). The screw (201) is designed for mixing rubber crumbs and chips with a modifier and uniformly feeding rollers into the gap. A slit nozzle (208) is attached to the lower part of the housing (200), which is equipped with a mechanism (209) for adjusting the gap of the slit. The feed device (3) is provided with a cover (210) on which the neck (211) is mounted. Through the specified neck, the device is loaded with material for regeneration. A nozzle (212) is installed on one of the side walls of the housing (200), through which a portion of the modifier is supplied to the feeding device.

In fig. 3. shows a schematic design of a nutrient device (3), which has a V-shaped body (300). Inside the housing (300) is placed a mixing paddle (301). The triangular-shaped blade can move along the axis (302) and, in addition to mixing, provides a uniform supply of material through the slotted nozzle (311) into the gap between the rollers. The axis (302) is fixed in the bushings (303) and (304), which are mounted on the end walls (305) and (306) of the housing (300). The rotation of the mixing mechanism (301) is carried out by a reverse drive (307). The feed device (3) is provided with a cover (308) on which the neck (309) is mounted. Through the specified neck, the device is loaded with material for regeneration. A nozzle (310) is installed on one of the side walls of the housing (300), through which a portion of the modifier is supplied. A slit nozzle (311) is attached to the lower part of the housing (300), which is equipped with a mechanism (312) for adjusting the gap of the slit.

In fig. 4 shows a schematic design of a separation device (4). The separation device (4) is docked with the rotary mechanism (5). The separation device has a V-shaped housing (400). An unloading slot (401) is made in the lower part of the housing. On the end walls (402) and (403), the axes (404) and (405) are fixed. Suspensions (406) and (407) are mounted on these axes, with the help of which the separation device (4) is mounted on the frame of the mixing rolls (1). The sides (408) are attached to the body (400), which 1/3 cover the lower surfaces of the rollers (1). The separation device (4) is connected to the rotary mechanism (5) by means of a rod (409), hinged to a crank (410).

In fig. 5 shows a schematic construction of a separation barrier (6), the housing (500) of which is made in the form of a trihedral prism, that is, the side walls have the shape of an inclined slide. The housing is mounted on roller bearings (501) and (502). The support bodies are fixed to the end walls (503) and (504). On these end walls are fixed rods (505) and (506), which are interconnected by a beam (507). A separation barrier (6) is mounted on rails (508) along which the device can be moved by means of an actuator (509), for example, of a pneumatic type. On the rails (508), limiters (510) are installed on both sides, which ensure the fixing of the device during operation.

The work of the installation of the recovery of waste rubber, chips, chips and chips is as follows. Crumb rubber, chips and chips from the processing of worn tires that do not contain synthetic threads and wires are accumulated in the hopper (12). The portion weight is automatically determined by the weight dispenser (13). To obtain high quality regenerate, the feedstock must be sorted by type of rubber waste. During regeneration in each loading portion, crumbs, chips and chips from truck tires and buses, passenger car tires and from jeeps are used separately. The prepared powder modifier, for example, a mixture of powder urea with oxalic acid powder in a proportion of 52/48% (weight units) is accumulated in a container (16). The amount of modifier introduced depends on the type of waste being recycled. For example, for crumbs and chips from passenger car tires manufactured at European plants, the amount of modifier introduced is 25-30 grams per 1 kg of regenerated waste. A portion of crumb rubber and chips is fed into the mixer (14). Powder modifier is supplied in two stages. At the first stage, not more than 45-50% (weight units) of the modifier from the tank (16) is fed into the mixer (14). The feed is made through a dispenser (17) with a pneumatic conveying ejector (18) and a 3-way shutter (18) through a pipeline (20). The stirrer (15) is turned on and the modifier is mixed with the material intended for regeneration within 2.0-2.5 minutes. Open the shutter (22) and feed the material to the conveyor (10) and then through the specified conveyor to the feed device (3).

Depending on the type of material being regenerated, one to two passes of the portion through the rollers are carried out (10). According to the type of material being regenerated, the gap adjuster (2) sets the required design gap between the rollers.

The working gap of the mixing shafts for the first pass of a batch of material during processing is set depending on the maximum dimensions of the processed chips and chips, but not more than 3 mm. In subsequent passes of the processed material, the working interval of the rollers is reduced to the minimum possible. Depending on the type of devulcanized waste and the type of regenerate obtained, the minimum gap between the rollers can be 0.25-0.45 mm. The regulation of the gap between the rollers is set using the regulators (2). The minimum gap between the rollers (1) corresponds to the technical data of the accepted design of the mixing rollers. The duration of the process of devulcanization of a portion of rubber waste, chips and chips is 8-12 minutes, depending on the size of the feedstock and the quality of the modifier used.

With subsequent passes of the material into the feed device (3) through the pipe (21) through the nozzle (212) or (310) [see Fig. 2 and fig. 3] serve another 50-55% of the modifier. Mix the modifier with the material for 2.0 ... 2.5 minutes. Open the crevice nozzle (208) or (310) [see fig. 2 and fig. 3] and pass the material through the rollers (1). From the rollers (1), the regenerated material enters the separation device (4) and then to the barrier (6). When carrying out technological passes of the material through the rollers (1), the separation device (4) and the barrier (6) are installed in a position that ensures that the material enters the return conveyor (7). The necessary position of the separation device (4) and the barrier (6) is set using the rotary mechanism (5) and the mechanism (509). Further, the material enters the intermediate conveyor (9), and from it to the conveyor (10) and into the feeding device (3). The supply of the modifier in two stages reduces the number of passes of a portion of the regenerated material through the rollers from 10-11 to 5-6 passes. This reduces the duration of the regeneration, and the quality of the regenerator remains at a high level. After the last passage of the regenerated material through the rollers, the mechanism (5) and (509) and the separation device (4) are turned on, and the barrier (6) is set in a position that ensures that the material enters the conveyor (8) and then into the accumulator (23). The last pass of a portion of the material ensures the end of the regeneration process (devulcanization). Ready regenerate from the drive (23) is served on the packaging.

The operation of the installation is fully automated. The feed rates of the material to the feed device (3) and to the rollers (1) according to the conveyor system (7) - (10) are optimized in accordance with the time of supply of the starting material and mixing of the material with the modifier in the mixer (14) and the feed device (3).

5. The main advantages of the method and installation for the recovery of rubber waste

The advantages of the method and installation for the regeneration (devulcanization) of rubber-containing waste provide the goal of the invention: improving the quality of the final product, fully preserving the original composition of rubber waste, crumbs and chips, reducing energy consumption during the regeneration of rubber waste and reducing the cost of processing.

5.1. To carry out the regeneration process on roller equipment, it is not necessary to grind rubber waste, crumbs and chips to the minimum sizes that are provided for in other technological schemes, for example, during devulcanization in worm machines.

5.2. The method and installation are adapted to the ozone and ozone-cryogenic technology for processing rubber wastes and rubber-containing wastes from the processing of old vehicle tires, which ensures the complete absence of synthetic threads and pieces of steel wire in the material.

5.3. With the appropriate selection of modifier, the installation allows not only the regeneration of rubber waste and crumbs from the processing of old tires, but also a partial modification of rubber. Such rubber can be used directly for the manufacture of rubber products.

5.4. The introduction of the powder modifier in two stages provides improved adhesion of the modifier particles on the surface of the regenerated material and minimizes the consumption of the modifier.

5.5. The supply of the modifier in two stages reduces the number of passes of a portion of the regenerated material through the rollers from 10-11 to 5-6 passes. This reduces the duration of the regeneration, and the quality of the regenerator remains at a high level.

Claims (14)

1. The method of regeneration of rubber wastes from rubber industries, as well as rubber-containing wastes, in particular crumbs, shavings and chips obtained after processing of old vehicle tires, characterized in that: (1) a powder modifier is prepared and stored in a container, which for passenger car tires is a mixture of urea powder and oxalic acid powder in a proportion of 52:48 wt.%; (2) as old vehicle tires use old passenger car tires in the form of chips, chips and chips, the amount of input modifier is 25-30 g / kg of recovered waste; (3) the supply of the modifier is carried out in two stages, while in the first stage the modifier is fed into the mixer in an amount of not more than 45-50 wt.%; (4) a batch of waste with a modifier is mixed in the mixer for 2.0-2.5 minutes; (5) supplying the indicated portion of the material to the feeding device and performing one or two portion passes through the rollers; (6) in the second stage, in the nutrient device, 55-50 wt.% Of the modifier is added to the regenerated portion of the material and mixed for 2.0-2.5 minutes; (7) carry out 5-6 passes of a portion of the material through the rollers, reducing the gap between the rollers by 0.3-0.4 mm after each pass; (8) the resulting regenerate in the form of spongy crumbs or thin sheets is fed to the storage of finished products. 2. Installation for the recovery of rubber wastes from rubber industries, as well as rubber-containing wastes, in particular crumbs, shavings and chips obtained after processing of old vehicle tires, including: a) mixing rollers with a drive, as well as a gap adjuster between the rollers; b) a feed device with a screw-type mixer, which at the same time is a distributor for uniformly supplying regenerate through the slot nozzle into the gap between the rollers; c) a feeding device that has a blade-type mixing mechanism provided with a drive for moving the blade, in which the regenerate is uniformly fed through the slot nozzle into the gap between the rollers; d) a separation device consisting of a V-shaped housing that is connected to a rotary device and provided with an unloading slot; e) a separation barrier made in the form of a trihedral prism, which has roller bearings supported by two guides and is equipped with a drive for moving it along the guides. 3. Installation according to claim 2, characterized in that the distributor of the nutrient device is made in the form of a multidirectional screw. 4. Installation according to claim 2, characterized in that the distributor of the feeding device is made in the form of a scraper-blade, which moves along the outlet slit along the guide shaft. 5. Installation according to p. 2, characterized in that the separation device is equipped with a rotary mechanism and a rod connected to the crank mechanism. 6. Installation according to claim 2, characterized in that the separation barrier is fixed on the support rollers and mounted on rails. 7. Installation according to claim 2, characterized in that the separation barrier is moved relative to the working gap between the rollers using a pneumatic drive.

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