Conveying apparatus and its use, device and method for pre-treatment of PVC-containing waste plastics

Abstract

The present application relates to the technical field of waste plastic pretreatment, in particular to a conveying device and application thereof, and a device and method for pretreatment of waste plastic containing PVC. The conveying device provided by the present application is easier to convey the material after the material is soaked by the separating fluid by setting the spraying device and the propelling screw. The conveying device provided by the present application is used for pretreatment of waste plastic containing PVC, which can solve the problem of difficult conveying of waste plastic caused by small waste plastic bulk specific gravity, strong interaction between particles and other reasons, and can effectively remove PVC in the waste plastic, so that the chlorine content in the dechlorinated waste plastic is less than 2000 ppm.

Description

Technical Field

[0001] The present invention relates to the technical field of waste plastic pretreatment, and in particular to a conveying device and application thereof, and a device and method for pretreating waste plastic containing PVC. Background Art

[0002] Waste plastics are often complex in composition. For example, if they contain a large amount of PVC, chlorine can corrode downstream processing equipment, increasing investment and safety risks. Therefore, before waste plastics are further processed into oils or chemicals, pretreatment techniques are required to remove components that are harmful to subsequent processing steps, or to remove more valuable components.

[0003] During the pretreatment of waste plastics, due to their small bulk ratio, strong interaction between particles, and strong electrostatic adsorption, they are very likely to accumulate and stagnate at the diameter change of related equipment and in the conveying pipelines, which in turn leads to blockage problems and seriously affects the normal progress of the process. CN204263409U discloses a waste plastic cleaning and separation device, comprising: a conveying device, a first hot cleaning and separation system, a second hot cleaning system, a third cleaning and separation system, and a dehydration device. The conveying device is a belt feeder. The device uses a variety of equipment to solve the problem of conveying waste plastics, but the problem of conveying waste plastics on the connecting pipelines between the various processes has not been solved. At the same time, the device is only suitable for normal pressure systems and is not very applicable to related processes of chemical recovery. Therefore, there is an urgent need for a conveying device that can be used for pretreatment of PVC-containing waste plastics in a pressurized system. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of difficult transportation, high energy consumption, and difficult separation of PVC from waste plastics in existing conveying equipment used for pretreatment of PVC-containing waste plastics. A conveying equipment and its application, a device and method for pretreatment of PVC-containing waste plastics are provided. The conveying equipment solves the problem of difficult transportation caused by small waste plastic pile ratio, strong interaction force between particles, etc.; the device containing the conveying equipment solves the problem of separating PVC from waste plastics and reduces energy consumption.

[0005] To achieve the above-mentioned object, the present invention provides a conveying device in a first aspect, comprising: a housing, and a transmission device, a fluid inlet, a material inlet, and a material outlet provided on the housing; the housing is divided from top to bottom into a material storage section, a diameter-changing section, and a conveying section, which are interconnected;

[0006] The shell is provided with a spraying device connected to the fluid inlet; the shell is also provided with a propulsion screw connected to the transmission device, and the propulsion screw longitudinally passes through the storage section, the diameter-changing section and the conveying section;

[0007] The transmission device drives the propeller screw, so that the material added through the material inlet and the separation fluid added through the fluid inlet are contacted and mixed in the housing, and the obtained mixed material is discharged through the material outlet.

[0008] The inner diameter of the storage section is greater than the inner diameter of the conveying section.

[0009] The second aspect of the present application provides an application of the conveying device provided in the first aspect in the pretreatment of PVC-containing waste plastics.

[0010] The third aspect of the present application provides a device for pretreating PVC-containing waste plastics, which comprises, in sequence, a waste plastic bin, a conveying device provided in the first aspect, a separation device, a first separation device, and a dechlorinated waste plastic tank, and a fluid recovery tank in communication with the separation device.

[0011] The waste plastic bin is connected to the material inlet of the conveying device, and is used to introduce the PVC-containing waste plastics into the conveying device.

[0012] The conveying device is used to contact and mix the separation fluid and the PVC-containing waste plastics to obtain a mixed material.

[0013] The separation device is used to centrifugally separate the mixed material and the supplemental separation fluid to obtain a centrifugal fluid, dechlorinated light waste plastics, and chlorine-containing heavy waste plastics.

[0014] The first separation device is used to first separate the dechlorinated light waste plastics to obtain dechlorinated waste plastics and a first separation fluid.

[0015] The dechlorinated waste plastic tank is used to store the dechlorinated waste plastics.

[0016] The fluid recovery tank is used to recover the centrifugal fluid as a circulating separation fluid.

[0017] The fourth aspect of the present application provides a method for pretreating PVC-containing waste plastics, which comprises the following steps:

[0018] (1) In the conveying device provided in the first aspect, the PVC-containing waste plastics added through the material inlet and the separation fluid added through the fluid inlet are contacted and mixed under the action of the transmission device driving the propeller screw to obtain a mixed material.

[0019] (2) The mixed material and the supplemental separation fluid are centrifugally separated to obtain a centrifugal fluid, dechlorinated light waste plastics, and chlorine-containing heavy waste plastics.

[0020] (3) The dechlorinated light waste plastics are first separated to obtain dechlorinated waste plastics and a first separation fluid.

[0021] The centrifuged fluid is returned as a circulating separation fluid and mixed into the separation fluid.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The conveying equipment provided by the present invention is provided with a spraying device and a propulsion screw, so that the material is more easily conveyed after being infiltrated by the separation fluid. In particular, the rotation speed of the propulsion screw in the conveying equipment, the decreasing amplitude of the pitch of the spiral blade in the variable diameter section, and the increasing amplitude of the pitch of the spiral blade in the conveying section are limited, which is more conducive to the conveying of materials;

[0024] (2) The conveying equipment provided by the present invention is used for the pretreatment of PVC-containing waste plastics, which can solve the problem of difficult waste plastic transportation caused by the small waste plastic pile ratio and strong interaction force between particles;

[0025] (3) The method for pretreating PVC-containing waste plastics provided by the present invention can effectively remove PVC from the waste plastics. Specifically, after the mixed material passes through the conveying equipment, the chlorine-containing substances (i.e., chlorine-containing heavy waste plastics) and the dechlorinated substances (i.e., dechlorinated light waste plastics) in the waste plastics are separated. Then, combined with the dechlorination separation equipment, the chlorine content in the dechlorinated waste plastics is reduced to less than 2000 ppm (by mass); compared with the chemical pretreatment method, this method reduces energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a conveying device provided by the present invention;

[0027] Figure 2 The present invention provides a schematic diagram of a device for recycling and pre-treating PVC waste plastics.

[0028] Description of Reference Numerals

[0029] 1. Waste plastic warehouse 2. Conveying equipment 3. Separation equipment

[0030] 4. Fluid recovery tank 5. First de-separation equipment 6. Dechlorination waste plastic tank

[0031] 7. Chlorine-containing waste plastic tank 8. Machine miscellaneous collection tank 9. Second conveyor

[0032] 10. Second separation equipment 11. First conveyor

[0033] 001. PVC-containing waste plastics 002. Separation fluid 003. Mixed materials

[0034] 004. Supplementary separation fluid 005. Centrifugal separation fluid 006. Dechlorination of light waste plastics

[0035] 007, chlorine-containing heavy plastic waste 008, dechlorinated waste plastic 009, first separation fluid

[0036] 010, chlorine-containing waste plastics 011, second separation fluid 012, solid machine miscellaneous

[0037] 21. Material inlet 22. Fluid inlet 23. Transmission equipment

[0038] 24. Spraying equipment 25. Propelling screw 26. Variable diameter section

[0039] 27. Material outlet 28. Material storage section 29. Conveying section DETAILED DESCRIPTION

[0040] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0041] In the present invention, unless otherwise specified, the terms "first" and "second" do not indicate a sequence or limit the materials or steps involved. They are used only to distinguish between different materials or steps. For example, the terms "first" and "second" in "first de-separated fluid" and "second de-separated fluid" are used only to distinguish between different separated fluids; the terms "first" and "second" in "first conveyor" and "second conveyor" are used only to distinguish between different conveyors.

[0042] A first aspect of the present invention provides a conveying device, comprising: a housing, and a transmission device, a fluid inlet, a material inlet, and a material outlet provided on the housing; the housing is divided from top to bottom into a communicating material storage section, a diameter-changing section, and a conveying section, each of the material storage section, the diameter-changing section, and the conveying section being independently provided with a propulsion screw;

[0043] The shell is provided with a spraying device connected to the fluid inlet; the shell is also provided with a propulsion screw connected to the transmission device, and the propulsion screw longitudinally passes through the storage section, the diameter-changing section and the conveying section;

[0044] The transmission device drives the propulsion screw, so that the material added through the material inlet and the separation fluid added through the fluid inlet contact and mix in the housing, and the obtained mixed material is discharged through the material outlet;

[0045] Wherein, the inner diameter of the storage section is greater than the inner diameter of the conveying section.

[0046] The inventors of the present invention have discovered that by providing a spraying device in the conveying equipment, the density of waste plastic particles or membranes is significantly increased, while the interaction force between the waste plastics is destroyed, making the waste plastics easier to convey; providing a propulsion screw in the conveying equipment makes it easier to convey the waste plastics, especially limiting the propulsion screw to have different pitches at different cross-sectional diameters, that is, regulating the diameter and pitch of the propulsion screw in the storage section, the variable diameter section and the conveying section, which is more conducive to improving the conveying of waste plastics.

[0047] At the same time, based on the conveying equipment, a device for pre-treating PVC-containing waste plastics is provided. Specifically, the conveying equipment is combined with a centrifugal device to separate chlorine-containing substances and non-chlorine-containing substances in the waste plastics, that is, chlorine-containing heavy waste plastics and dechlorinated light waste plastics are obtained. Then, combined with the de-separation equipment (that is, the first de-separation equipment and the second de-separation equipment), chlorine-containing waste plastics and dechlorinated waste plastics are obtained, especially the chlorine content in the dechlorinated waste plastics is lower than 2000ppm.

[0048] In the present invention, unless otherwise specified, the fluid inlet and the spraying device are connected via a pipeline; and the transmission device and the propulsion screw are connected via a pipeline.

[0049] In the present invention, the fluid inlet is connected to the spraying device, allowing the separated fluid to be evenly distributed across the axial cross-section of the conveying device, thereby moistening the waste plastics. Because waste plastics are small in bulk, lightweight, and prone to bridging, conveying them in a dry state is significantly more difficult than in a wet state. The provision of the spraying device ensures that the waste plastics are fully moistened, making them easier to convey under the action of the propulsion screw.

[0050] According to the present invention, preferably, the inner diameter ratio of the storage section and the conveying section is 1.1-10:1, for example, 1.1:1, 2:1, 3:1, 4:1, 5:1, 8:1, 10:1, and any value in the range of any two values, preferably 2-5:1.

[0051] According to the present invention, the height ratio of the storage section, the reducing section, and the conveying section in the housing is preferably 1-10:0.1-1:0.1-10, and more preferably 1-5:0.25-1:0.5-2. In the present invention, the height of the conveying section should be minimized to reduce the occurrence of bridging, while ensuring that space for relevant cutouts or seals is reserved within the conveying section. By adjusting the height ratio of the storage section to the reducing section, and thereby controlling the inclination angle of the reducing section, conditions are provided to facilitate the falling of solids.

[0052] In the present invention, the propulsion screw is driven by the transmission device. Preferably, the propulsion screw has a rotation speed of 0.5-60 rpm, for example, 0.5 rpm, 1 rpm, 5 rpm, 10 rpm, 15 rpm, 20 rpm, 25 rpm, 30 rpm, 40 rpm, 60 rpm, and any value in a range consisting of any two values, preferably 1-30 rpm, more preferably 15-30 rpm.

[0053] According to the present invention, preferably, the propulsion screw is composed of at least one spiral blade. In the present invention, there is no limitation on the type of the spiral blade, which are all conventional spiral blades in the art.

[0054] In the present invention, as the mixed material transitions from the storage section to the variable diameter section, the diameter of the spiral blades gradually decreases, and at the same time, the pitch of the spiral blades also gradually decreases, thereby compacting the waste plastic in the storage section and conveying it downstream. Preferably, the diameter of the spiral blades in the variable diameter section gradually decreases along the direction of material flow; further preferably, the pitch of the spiral blades in the variable diameter section gradually decreases along the direction of material flow.

[0055] In some embodiments of the present invention, preferably, along the material flow direction, the pitch of the spiral blades in the variable diameter section decreases in sequence by 1-15%, preferably by 1-10%.

[0056] According to the present invention, preferably, the pitch of the spiral blades in the conveying section gradually increases along the material flow direction, so that the compacted waste plastics in the mixed material gradually become fluffy, which is conducive to conveying.

[0057] In some embodiments of the present invention, preferably, along the material flow direction, the pitch of the spiral blades in the conveying section increases successively by 1-15%, preferably by 1-10%.

[0058] In some embodiments of the present invention, preferably, the ratio of the diameter of the spiral blade in the storage section to the inner diameter of the storage section is 0.3-0.8:1, preferably 0.4-0.7:1; the ratio of the width of the spiral blade in the storage section to the inner diameter of the storage section is 0.02-0.6:1, preferably 0.2-0.4:1.

[0059] In some embodiments of the present invention, preferably, the ratio of the diameter of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.3-0.8:1, preferably 0.4-0.7:1; the ratio of the width of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.02-0.6:1, preferably 0.2-0.4:1.

[0060] The present invention provides a structural diagram of a conveying device, such as Figure 1 As shown, the conveying device includes: a housing, and a transmission device 23, a fluid inlet 22, a material inlet 21 and a material outlet 27 arranged on the housing; the housing is divided into a material storage section 28, a diameter-changing section 26 and a conveying section 29 which are interconnected from top to bottom;

[0061] The housing is provided with a spray device 24 connected to the fluid inlet 22; the housing is also provided with a propulsion screw 25 connected to the transmission device 23, and the propulsion screw 25 longitudinally penetrates the storage section 28, the diameter-changing section 26 and the conveying section 29; the propulsion screw 25 is composed of spiral blades;

[0062] The transmission device 23 drives the propulsion screw 25, so that the material added by the material inlet 21 and the separation fluid added by the fluid inlet 22 contact and mix in the housing, and the obtained mixed material is discharged through the material outlet 27;

[0063] Among them, the inner diameter of the storage section 28 is greater than the inner diameter of the conveying section 27;

[0064] In the material flow direction, the diameter of the spiral blade in the diameter-changing section 26 gradually decreases, the pitch of the spiral blade in the diameter-changing section 26 gradually decreases, and the pitch of the spiral blade in the conveying section 29 gradually increases.

[0065] According to a particularly preferred embodiment of the present invention, the conveying device comprises: a housing, and a transmission device, a fluid inlet, a material inlet, and a material outlet provided on the housing; the housing is divided into a communicating material storage section, a diameter-changing section, and a conveying section from top to bottom, and each of the material storage section, the diameter-changing section, and the conveying section is independently provided with a propulsion screw;

[0066] The shell is provided with a spraying device connected to the fluid inlet; the shell is also provided with a propulsion screw connected to the transmission device, and the propulsion screw longitudinally passes through the storage section, the diameter-changing section and the conveying section;

[0067] The transmission device drives the propulsion screw, so that the material added through the material inlet and the separation fluid added through the fluid inlet contact and mix in the housing, and the obtained mixed material is discharged through the material outlet;

[0068] The inner diameter ratio of the storage section and the conveying section is 2-5:1; the rotation speed of the propulsion screw is 15-30 rpm;

[0069] Wherein, along the material flow direction, the pitch of the spiral blade in the variable diameter section decreases by 1-10%; along the material flow direction, the pitch of the spiral blade in the conveying section increases by 1-10%;

[0070] Among them, the ratio of the diameter of the spiral blade in the storage section to the inner diameter of the storage section is 0.4-0.7:1; the ratio of the width of the spiral blade in the storage section to the inner diameter of the storage section is 0.2-0.4:1; the ratio of the diameter of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.4-0.7:1; the ratio of the width of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.2-0.4:1.

[0071] A second aspect of the present invention provides an application of the conveying equipment provided in the first aspect in the pretreatment of waste plastics containing PVC.

[0072] A third aspect of the present invention provides a device for pre-treating waste plastics containing PVC, the device comprising: a waste plastics bin, the conveying device, the separation device, the first de-separation device and the dechlorination waste plastics tank provided in the first aspect, which are sequentially connected, and a fluid recovery tank connected to the separation device;

[0073] The waste plastic bin is connected to the material inlet of the conveying device, and is used to introduce the waste plastic containing PVC into the conveying device;

[0074] The conveying device is used to contact and mix the separation fluid and the PVC-containing waste plastic to obtain a mixed material;

[0075] The separation device is used to centrifugally separate the mixed material and the supplementary separation fluid to obtain centrifugal fluid, dechlorinated light waste plastics and chlorinated heavy waste plastics;

[0076] The first de-separation device is used to perform a first de-separation on the dechlorinated light waste plastic to obtain the dechlorinated waste plastic and a first de-separation fluid;

[0077] The dechlorinated waste plastic tank is used to store the dechlorinated waste plastic;

[0078] The fluid recovery tank is used to recover the centrifugal fluid as a circulating separation fluid.

[0079] In the present invention, unless otherwise specified, the dechlorinated light plastic waste and chlorinated heavy plastic waste are based on whether they contain PVC substances, and generally the PVC density is greater than 1.2 g / cm 3 , it is identified as chlorine-containing heavy waste plastic, otherwise it is dechlorinated light waste plastic.

[0080] In the present invention, the type of the separation device is not limited. Preferably, the separation device is a high-efficiency centrifuge with a rotation speed of ≥8000 rpm, preferably 8000-10000 rpm, and a separation time of 1-30 min, preferably 5-20 min.

[0081] According to the present invention, preferably, the fluid recovery tank is connected to the fluid inlet of the conveying device to provide the separation fluid to the conveying device, so that the PVC-containing waste plastics are fully wetted for easy transportation.

[0082] According to the present invention, preferably, the outlet of the fluid recovery tank is also connected to the inlet of the separation device, for providing the supplementary separation fluid to the separation device, and providing the total amount of fluid required for the separation device to achieve a certain separation efficiency (i.e., separation fluid and supplementary separation fluid), thereby improving the separation efficiency of the mixed material.

[0083] According to the present invention, preferably, the first de-separation fluid outlet of the first de-separation device is connected to the inlet of the fluid recovery tank, so as to recover the first de-separation fluid as a circulating separation fluid.

[0084] According to the present invention, preferably, the device further comprises: a first conveyor connecting the outlet of the dechlorinated light waste plastic of the separation device and the inlet of the first de-separation device.

[0085] According to the present invention, preferably, the device further comprises: a second de-separation device connected to the chlorine-containing heavy waste plastic outlet of the separation device, for performing a second de-separation on the chlorine-containing heavy waste plastic to obtain chlorine-containing waste plastic, a second de-separation fluid and solid impurities.

[0086] According to the present invention, preferably, the second de-separation fluid outlet of the second de-separation device is connected to the inlet of the fluid recovery tank, so as to recover the second de-separation fluid as a circulating separation fluid.

[0087] According to the present invention, preferably, the device further comprises: a second conveyor connecting the chlorine-containing heavy waste plastic outlet of the separation device and the inlet of the second separation device.

[0088] According to the present invention, preferably, the device further comprises: a chlorine-containing waste plastic tank connected to the chlorine-containing waste plastic outlet of the second de-separation device, for storing the chlorine-containing waste plastic.

[0089] According to the present invention, preferably, the device further comprises: an impurity collection tank connected to the solid impurity outlet of the second separation device, for collecting the solid impurities.

[0090] The present invention provides a schematic diagram of a device for pre-treating PVC waste plastics, as shown in FIG. Figure 1-2 As shown, the device comprises: a waste plastic bin 1, a conveying device 2 provided in the first aspect, a separation device 3, a first conveyor 11, a first de-separation device 5 and a dechlorinated waste plastic tank 6, and a fluid recovery tank 4 connected to the separation device 3;

[0091] The fluid recovery tank 4 is connected to the fluid inlet 22 of the conveying device 2, and is also connected to the inlet of the separation device 3; the first desorption fluid outlet of the first desorption device 5 is connected to the inlet of the fluid recovery tank 4.

[0092] The waste plastic bin 1 is connected to the material inlet 21 of the conveying device 2, and is used to introduce the PVC-containing waste plastic 001 into the conveying device 2; the conveying device 2 is used to contact and mix the separation fluid 002 and the PVC-containing waste plastic 001, and obtain a mixed material 003; the separation device 3 is used to centrifugally separate the mixed material 003 and the supplementary separation fluid 004, and obtain a centrifugal fluid 005, a dechlorinated light waste plastic 006 and a chlorine-containing heavy waste plastic 007; the first desorption device 5 is used to perform first desorption on the dechlorinated light waste plastic 006, and obtain a dechlorinated waste plastic 008 and a first desorption fluid 009; the dechlorinated waste plastic tank 6 is used to store the dechlorinated waste plastic 008; and the fluid recovery tank 4 is used to recover the centrifugal fluid 005 as a circulating separation fluid.

[0093] The device further comprises a second conveying machine 9, a second desorption device 10 and a chlorine-containing waste plastic tank 7 connected in sequence with the chlorine-containing heavy waste plastic outlet of the separation device 3; the second desorption device 10 is used to perform second desorption on the chlorine-containing heavy waste plastic 007, and obtain a chlorine-containing waste plastic 010, a second desorption fluid 011 and a solid machine sundry 012; and the second desorption fluid outlet of the second desorption device 10 is connected to the inlet of the fluid recovery tank 4.

[0094] The device further comprises a machine sundry collection tank 8 connected with the solid machine sundry outlet of the second desorption device 10.

[0095] The fourth aspect of the present application provides a method for pretreating PVC-containing waste plastic, which comprises the following steps:

[0096] (1) In the conveying device provided in the first aspect, the PVC-containing waste plastic added through the material inlet and the separation fluid added through the fluid inlet are contacted and mixed under the action of the transmission device driving the propelling screw, and a mixed material is obtained;

[0097] (2) The mixed material and the supplementary separation fluid are centrifugally separated, and a centrifugal fluid, a dechlorinated light waste plastic and a chlorine-containing heavy waste plastic are obtained;

[0098] (3) The dechlorinated light waste plastic is subjected to first desorption, and a dechlorinated waste plastic and a first desorption fluid are obtained;

[0099] The centrifugal fluid is returned and mixed into the separation fluid as a circulating separation fluid.

[0100] In some embodiments of the present application, preferably, in step (1), the weight ratio of the PVC-containing waste plastic and the separation fluid is 1:0.1-10, for example, 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:7, 1:8, 1:10, and any value within the range of any two values, preferably 1:0.5-7, and more preferably 1:0.5-5. The smaller the weight ratio, the faster and greater the wetting of the PVC-containing waste plastic, which is beneficial for conveying. However, the larger the weight ratio, the greater the total volume and weight of the separation fluid, which reduces the technical and economic efficiency.

[0101] In some embodiments of the present application, preferably, the PVC content is 1-50 wt%, and more preferably 1-25 wt%, based on the total weight of the PVC-containing waste plastic. The concentration of chloride ions in the waste plastic is measured by dissolving the waste plastic and then measuring the chlorine content by ICP.

[0102] In the present application, the separation fluid is a fluid that changes the surface tension or density of the material. Preferably, the separation fluid is selected from at least one of water, an optional inorganic substance, and an optional organic substance.

[0103] In some embodiments of the present application, preferably, the water content is 0-100 wt%, and more preferably 90-100 wt%, based on the total weight of the separation fluid; the inorganic substance content is 0-50 wt%, and more preferably 0-15 wt%; and the organic substance content is 0-50 wt%, and more preferably 0-15 wt%.

[0104] In some embodiments of the present application, preferably, the inorganic substance is a soluble compound, and is preferably selected from at least one of sodium chloride, calcium chloride, sodium nitrate, sodium hydroxide, and potassium hydroxide.

[0105] In some embodiments of the present application, preferably, the organic substance is selected from at least one of a non-polar organic substance, a polar organic substance, and a surfactant; further preferably, the non-polar organic substance includes, but is not limited to, at least one of acetone, tetrabromoethane, ethanol, ethylene glycol, and glycerol; the polar organic substance includes, but is not limited to, at least one of methanol, ethanol, tetrahydrofuran, and DMF (N,N-dimethylformamide); and the surfactant includes, but is not limited to, at least one of sulfated oil, higher fatty alcohol sulfate, and sodium dodecylbenzenesulfonate.

[0106] In some embodiments of the present invention, preferably, in step (2), the weight ratio of the mixed material to the supplementary separation fluid is 1:10-100, for example, 1:10, 1:20, 1:30, 1:40, 1:50, 1:80, 1:100, and any value in the range consisting of any two values, preferably 1:20-50.

[0107] In the present invention, the centrifugal separation is intended to separate the mixed material into centrifugal fluid, dechlorinated light waste plastics, and chlorinated heavy waste plastics. Preferably, in step (2), the centrifugal separation conditions include: a rotation speed ≥ 8000 rpm, preferably 8000-10000 rpm; and a time of 1-30 min, preferably 5-20 min.

[0108] In the present invention, the first de-separation is intended to further remove the centrifugal fluid remaining in the dechlorinated light plastic waste to obtain the dechlorinated waste plastic. Preferably, in step (3), the conditions for the first de-separation include: a rotation speed ≥ 10,000 rpm, preferably 10,000-15,000 rpm; and a time of 1-30 minutes, preferably 5-15 minutes.

[0109] According to the present invention, preferably, the method further comprises: returning the first de-separated fluid as a circulating separation fluid and mixing the fluid into the separation fluid.

[0110] According to the present invention, preferably, the method further comprises: subjecting the chlorine-containing heavy waste plastic to a second de-separation to obtain chlorine-containing waste plastic, a second de-separation fluid and solid impurities.

[0111] In the present invention, the second de-separation is intended to further remove the residual centrifugal fluid and some of the residual dechlorinated light plastic waste from the chlorinated heavy plastic waste, thereby obtaining chlorinated waste plastic. Preferably, the second de-separation is performed at a rotation speed of ≥4000 rpm, preferably 5000-6000 rpm, and for a duration of 1-30 minutes, preferably 5-15 minutes.

[0112] According to the present invention, preferably, the method further comprises: returning the second de-separated fluid as a circulating separation fluid and mixing the second de-separated fluid into the separation fluid.

[0113] The present invention will be described in detail below through examples.

[0114] In the examples and comparative examples, the chlorine content in the chlorine-containing waste plastics and the dechlorinated waste plastics was measured by first dissolving the chlorine-containing waste plastics and the dechlorinated waste plastics, and then measuring the chloride ion concentration by ICP and then calculating the result.

[0115] The PVC-containing waste plastics include polyethylene, polypropylene and PVC; wherein, based on the weight of the PVC-containing waste plastics, the PVC content is 20 wt%.

[0116] Calculation formula:

[0117]

[0118] The unit of chloride ion concentration in the solution of chlorine-containing waste plastics is g / g; the unit of mass of the solution of chlorine-containing waste plastics is g; and the unit of mass of chlorine-containing waste plastics is g.

[0119]

[0120] The unit of chloride ion concentration in the dechlorinated waste plastic solution is g / g; the unit of mass of the dechlorinated waste plastic solution is g; and the unit of mass of the dechlorinated waste plastic is g.

[0121] Example 1

[0122] (1) Conveying equipment, such as Figure 1 As shown, the conveying device includes: a housing, and a transmission device 23, a fluid inlet 22, a material inlet 21 and a material outlet 27 arranged on the housing; the housing is divided into a material storage section 28, a diameter-changing section 26 and a conveying section 29 which are interconnected from top to bottom;

[0123] The housing is provided with a spray device 24 connected to the fluid inlet 22; the housing is also provided with a propulsion screw 25 connected to the transmission device 23, and the propulsion screw 25 longitudinally penetrates the storage section 28, the diameter-changing section 26 and the conveying section 29; wherein the propulsion screw 25 is composed of spiral blades;

[0124] The transmission device 23 drives the propulsion screw 25, so that the material added by the material inlet 21 and the separation fluid added by the fluid inlet 22 contact and mix in the housing, and the obtained mixed material is discharged through the material outlet 27;

[0125] The inner diameter ratio of the storage section and the conveying section is 2:1; the height ratio of the storage section, the diameter-changing section and the conveying section in the shell is 4:1:2; the speed of the propulsion screw is 15 rpm;

[0126] Among them, along the direction of material flow, the diameter of the spiral blade in the diameter-changing section gradually decreases, the pitch of the spiral blade in the diameter-changing section decreases by 10%, and the pitch of the spiral blade in the conveying section increases by 10%;

[0127] The ratio of the diameter of the spiral blade in the storage section to the inner diameter of the storage section is 0.7:1; the ratio of the width of the spiral blade in the storage section to the inner diameter of the storage section is 0.3:1;

[0128] Among them, the ratio of the diameter of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.7:1; the ratio of the width of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.3:1.

[0129] (2) Equipment for pre-treatment of PVC waste plastics, such as Figure 2 As shown, the device includes: a waste plastic warehouse 1, the above-mentioned conveying equipment 2, a separation equipment 3, a first conveyor 11, a first de-separation equipment 5 and a dechlorinated waste plastic tank 6, which are connected in sequence, and a fluid recovery tank 4 connected to both the conveying equipment 2 and the separation equipment 3;

[0130] The fluid recovery tank 4 is connected to the fluid inlet 22 of the conveying device 2; the first de-separation fluid outlet of the first de-separation device 5 is connected to the inlet of the fluid recovery tank 4;

[0131] The device further comprises: a second conveyor 9, a second de-separation device 10 and a chlorine-containing waste plastic tank 7 which are sequentially connected to the chlorine-containing heavy waste plastic outlet of the separation device 3; wherein the second de-separation fluid outlet of the second de-separation device 10 is connected to the inlet of the fluid recovery tank 4;

[0132] The device further comprises: an impurity collection tank 8 connected to the solid impurity outlet of the second separation device 10 .

[0133] (3) A method for pretreating PVC-containing waste plastics, the method comprising:

[0134] a. In the above-mentioned conveying equipment, 100 g of PVC waste plastic and 300 g of deionized water are brought into contact and mixed under the action of a propulsion screw driven by a transmission device to obtain a mixed material;

[0135] b. Centrifugally separating the mixed material and 10 kg of supplementary deionized water to obtain a centrifugal fluid, dechlorinated light plastic waste, and chlorinated heavy plastic waste; the centrifugal separation was performed at a speed of 8000 rpm for 10 min;

[0136] c. performing a first de-separation on the dechlorinated light plastic waste to obtain dechlorinated waste plastic S1 and a first de-separation fluid; the conditions for the first de-separation include: a rotation speed of 10,000 rpm and a time of 5 minutes;

[0137] d. performing a second de-separation on the chlorine-containing heavy plastic waste to obtain chlorine-containing waste plastic P1, a second de-separation fluid, and solid impurities; the conditions for the second de-separation include: a rotation speed of 5000 rpm and a time of 5 minutes;

[0138] The centrifugal fluid, the first de-separation fluid and the second de-separation fluid are all recovered as circulating separation fluids.

[0139] The chlorine content in the dechlorinated waste plastic S1 is 0.084 wt %; the chlorine content in the chlorine-containing waste plastic P1 is 19.6 wt %.

[0140] Example 2

[0141] The method is as in Example 1, except that the setting of the conveying device is different, that is, the rotation speed of the propulsion screw is replaced with 10 rpm.

[0142] According to the device and method for pretreating PVC-containing waste plastics in Example 1, dechlorinated waste plastics S2 and chlorine-containing waste plastics P2 were obtained.

[0143] The chlorine content in the dechlorinated waste plastic S2 is 0.086 wt %; the chlorine content in the chlorine-containing waste plastic P2 is 19.1 wt %.

[0144] Example 3

[0145] According to Example 1, the difference is that the setting of the conveying equipment is different, that is, along the material flow direction, the pitch of the spiral blades in the variable diameter section decreases by 15% in sequence, and the pitch of the spiral blades in the conveying section increases by 15% in sequence.

[0146] According to the device and method for pretreating PVC-containing waste plastics in Example 1, dechlorinated waste plastics S3 and chlorine-containing waste plastics P3 were obtained.

[0147] The chlorine content in the dechlorinated waste plastic S3 is 0.09 wt %; the chlorine content in the chlorine-containing waste plastic P3 is 18.6 wt %.

[0148] Example 4

[0149] According to Example 1, the difference is that the setting of the conveying equipment is different, that is, the ratio of the diameter of the spiral blade in the storage section to the inner diameter of the storage section is replaced by 0.4:1; the ratio of the width of the spiral blade in the storage section to the inner diameter of the storage section is replaced by 0.1:1.

[0150] According to the device and method for pretreating PVC-containing waste plastics in Example 1, dechlorinated waste plastics S4 and chlorine-containing waste plastics P4 were obtained.

[0151] The chlorine content in the dechlorinated waste plastic S4 is 0.108 wt %; the chlorine content in the chlorine-containing waste plastic P4 is 16.3 wt %.

[0152] Example 5

[0153] According to Example 1, the difference is that the setting of the conveying equipment is different, that is, the ratio of the diameter of the spiral blade in the variable diameter section to the inner diameter of the variable diameter section is replaced by 0.4:1; the ratio of the width of the spiral blade in the variable diameter section to the inner diameter of the variable diameter section is replaced by 0.1:1.

[0154] According to the device and method for pretreating PVC-containing waste plastics in Example 1, dechlorinated waste plastics S5 and chlorine-containing waste plastics P5 were obtained.

[0155] The chlorine content in the dechlorinated waste plastic S5 is 0.111 wt %; the chlorine content in the chlorine-containing waste plastic P5 is 16.2 wt %.

[0156] Example 6

[0157] According to the conveying equipment and the device for pre-treating PVC waste plastics in Example 1;

[0158] The difference is that in the method for pretreatment of PVC-containing waste plastics, the rotation speed of centrifugal separation is replaced with 6000 rpm, and the remaining steps are the same to obtain dechlorinated waste plastic S6 and chlorine-containing waste plastic P6.

[0159] The chlorine content in the dechlorinated waste plastic S6 is 0.2 wt %; the chlorine content in the chlorine-containing waste plastic P6 is 14.5 wt %.

[0160] Comparative Example 1

[0161] 100g of the waste plastic mixture was conveyed to a standing container via a conveyor without spraying. After 5 minutes, the waste plastics were completely contained in the standing container. 2g of the mixture was removed from the standing container, supplemented with 100g of deionized water, and allowed to stand for 10 minutes. The liquid-solid mixture was rapidly frozen, and the suspended material in the upper layer was removed, melted, and dried to obtain dechlorinated waste plastic DS1.

[0162] The chlorine content in the dechlorinated waste plastic DS1 is 4.57 wt%.

[0163] Comparative Example 2

[0164] The method is similar to Example 1, except that the conveying device is configured differently and does not include a spraying device and a fluid inlet. That is, 100 g of PVC-containing waste plastic is directly conveyed under the action of a propulsion screw driven by a transmission device.

[0165] According to the device and method for pretreating PVC-containing waste plastics in Example 1, dechlorinated waste plastics DS2 and chlorine-containing waste plastics DP2 were obtained.

[0166] The chlorine content in the dechlorinated waste plastic DS2 is 0.32 wt %; the chlorine content in the chlorine-containing waste plastic DP2 is 12.3 wt %.

[0167] Compared with the comparative example, the conveying device provided by the application is used for pretreatment of the PVC-containing waste plastic, solves the problem of difficult conveying of the PVC-containing waste plastic, and further limits the rotation speed of the propelling screw in the conveying device, the decreasing amplitude of the pitch of the screw blade in the variable-diameter section, and the increasing amplitude of the pitch of the screw blade in the conveying section, which is more beneficial to the conveying of the waste plastic; meanwhile, in combination with centrifugal separation, the chlorine content in the waste plastic can be effectively separated, so that the chlorine content in the dechlorinated waste plastic is less than 2000ppm.

[0168] The preferred embodiments of the application are described in detail above, but the application is not limited thereto. Within the technical concept of the application, various simple modifications can be made to the technical solutions of the application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the application and belong to the protection scope of the application.

Claims

1. A conveying device for pre-processing PVC waste plastics, characterized in that: The conveying device comprises: a housing, and a transmission device, a fluid inlet, a material inlet and a material outlet arranged on the housing; the housing is divided into a material storage section, a diameter-changing section and a conveying section which are interconnected from top to bottom; The shell is provided with a spraying device connected to the fluid inlet; the shell is also provided with a propulsion screw connected to the transmission device, and the propulsion screw longitudinally passes through the storage section, the diameter-changing section and the conveying section; The transmission device drives the propulsion screw so that the material added through the material inlet and the separation fluid added through the fluid inlet contact and mix in the housing, and the resulting mixed material is discharged through the material outlet; the weight ratio of the material to the separation fluid is 1:0.5-5; The inner diameter of the material storage section is greater than the inner diameter of the conveying section; the height ratio of the material storage section, the diameter-changing section and the conveying section in the shell is 1-5:0.25-1:0.5-2; The propulsion screw has a rotation speed of 1-30 rpm; the propulsion screw is composed of at least one spiral blade; along the material flow direction, the pitch of the spiral blade in the variable diameter section decreases by 1-15% in sequence, and the pitch of the spiral blade in the conveying section increases by 1-15% in sequence; The ratio of the diameter of the spiral blade in the material storage section to the inner diameter of the material storage section is 0.3-0.8:1; the ratio of the width of the spiral blade in the material storage section to the inner diameter of the material storage section is 0.02-0.6:1; Wherein, the ratio of the diameter of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.3-0.8:1; the ratio of the width of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.02-0.6:

1.

2. The conveying device according to claim 1, wherein The inner diameter ratio of the storage section and the conveying section is 1.1-10:

1.

3. The conveying device according to claim 2, wherein: The inner diameter ratio of the storage section and the conveying section is 2-5:

1.

4. The conveying device according to claim 1, wherein The rotation speed of the propulsion screw is 15-30 rpm.

5. The conveying device according to claim 1, wherein Along the direction of material flow, the pitch of the spiral blades in the variable diameter section decreases in sequence by 1-10%; and / or, along the material flow direction, the pitch of the spiral blades in the conveying section increases in sequence by 1-10%; And / or, the ratio of the diameter of the spiral blade in the material storage section to the inner diameter of the material storage section is 0.4-0.7:1; the ratio of the width of the spiral blade in the material storage section to the inner diameter of the material storage section is 0.2-0.4:1; And / or, the ratio of the diameter of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.4-0.7:1; the ratio of the width of the spiral blade in the conveying section to the inner diameter of the conveying section is 0.2-0.4:

1.

6. A device for pre-treating waste plastics containing PVC, characterized in that: The device comprises: a waste plastic bin, a conveying device according to any one of claims 1 to 5, a separation device, a first de-separation device and a dechlorinated waste plastic tank, which are sequentially connected, and a fluid recovery tank connected to the separation device; The waste plastic bin is connected to the material inlet of the conveying device, and is used to introduce the waste plastic containing PVC into the conveying device; The conveying device is used to contact and mix the separation fluid and the PVC-containing waste plastic to obtain a mixed material; The separation device is used to centrifugally separate the mixed material and the supplementary separation fluid to obtain centrifugal fluid, dechlorinated light waste plastics and chlorinated heavy waste plastics; The first de-separation device is used to perform a first de-separation on the dechlorinated light waste plastic to obtain the dechlorinated waste plastic and a first de-separation fluid; The dechlorinated waste plastic tank is used to store the dechlorinated waste plastic; The fluid recovery tank is used to recover the centrifugal fluid as a circulating separation fluid.

7. The device according to claim 6, wherein The fluid recovery tank is connected to the fluid inlet of the conveying equipment; And / or, the outlet of the fluid recovery tank is also connected to the inlet of the separation device; and / or, the first de-separation fluid outlet of the first de-separation device is connected to the inlet of the fluid recovery tank, for recovering the first de-separation fluid as a circulating separation fluid; And / or, the device further comprises: a first conveyor connecting the outlet of the dechlorinated light waste plastic of the separation device and the inlet of the first dechlorination separation device.

8. The device according to claim 6 or 7, wherein: The device further comprises: a second de-separation device connected to the outlet of the chlorine-containing heavy plastic waste of the separation device, for performing a second de-separation on the chlorine-containing heavy plastic waste to obtain chlorine-containing waste plastic, a second de-separation fluid and solid impurities; and / or, the second de-separation fluid outlet of the second de-separation device is connected to the inlet of the fluid recovery tank, for recovering the second de-separation fluid as a circulating separation fluid; And / or, the apparatus further comprises: a second conveyor connecting the chlorine-containing heavy waste plastic outlet of the separation device and the inlet of the second de-separation device; And / or, the device further comprises: a chlorine-containing waste plastic tank connected to the chlorine-containing waste plastic outlet of the second de-separation device, for storing the chlorine-containing waste plastic; And / or, the device further comprises: a solid impurity collection tank connected to the solid impurity outlet of the second separation device, for collecting the solid impurities.

9. A method for pretreating PVC-containing waste plastics, characterized in that: The method comprises the following steps: (1) In the conveying device according to any one of claims 1 to 5, the PVC-containing waste plastics added through the material inlet and the separation fluid added through the fluid inlet are brought into contact and mixed under the action of the propulsion screw driven by the transmission device to obtain a mixed material; (2) centrifugally separating the mixed material and the supplementary separation fluid to obtain centrifugal fluid, dechlorinated light plastic waste, and chlorinated heavy plastic waste; (3) performing a first de-separation on the dechlorinated light waste plastic to obtain the dechlorinated waste plastic and a first de-separation fluid; The centrifuged fluid is returned as a circulating separation fluid and mixed into the separation fluid.

10. The method according to claim 9, wherein: In step (1), the PVC content is 1-50wt% based on the total weight of the PVC-containing waste plastic; And / or, the separation fluid is selected from at least one of water, inorganic matter and organic matter; based on the total weight of the separation fluid, the water content is 0-100wt%; the inorganic matter content is 0-50wt%; and the organic matter content is 0-50wt%.

11. The method according to claim 10, wherein: In step (1), the PVC content is 1-25 wt% based on the total weight of the PVC-containing waste plastic; and / or, based on the total weight of the separation fluid, the water content is 90-100 wt %; the inorganic matter content is 0-15 wt %; the organic matter content is 0-15 wt %; and / or, the inorganic substance is a soluble compound; And / or, the organic matter is selected from at least one of non-polar organic matter, polar organic matter and surfactant; the non-polar organic matter is selected from at least one of acetone, tetrabromoethane, ethanol, ethylene glycol and glycerol; the polar organic matter is selected from at least one of methanol, ethanol, tetrahydrofuran and DMF; the surfactant is selected from at least one of sulfated oil, higher fatty alcohol sulfate and sodium dodecylbenzenesulfonate.

12. The method according to claim 11, wherein In step (1), the inorganic substance is selected from at least one of sodium chloride, calcium chloride, sodium nitrate, sodium hydroxide and potassium hydroxide.

13. The method according to claim 9, wherein: In step (2), the weight ratio of the mixed material to the supplementary separation fluid is 1:10-100; And / or, the centrifugal separation conditions include: a rotation speed ≥ 8000 rpm; a time of 1-30 min; And / or, in step (3), the conditions for the first de-separation include: a rotation speed ≥ 10000 rpm; and a time of 1-30 min.

14. The method according to claim 13, wherein In step (2), the weight ratio of the mixed material to the supplementary separation fluid is 1:20-50; And / or, the centrifugal separation conditions include: a rotation speed of 8000-10000 rpm; a time of 5-20 min; And / or, in step (3), the conditions for the first de-separation include: a rotation speed of 10,000-15,000 rpm; and a time of 5-15 minutes.

15. The method according to any one of claims 9 to 14, wherein: The method further includes: returning the first de-separated fluid as a circulating separated fluid and mixing it into the separated fluid; And / or, the method further comprises: subjecting the chlorine-containing heavy waste plastic to a second de-separation to obtain chlorine-containing waste plastic, a second de-separation fluid and solid impurities.

16. The method according to claim 15, wherein The conditions for the second de-separation include: a rotation speed ≥ 4000 rpm; a time of 1-30 min; And / or, the method further comprises: returning the second de-separated fluid as a circulating separation fluid and mixing the second de-separated fluid into the separation fluid.

17. The method according to claim 16, wherein The conditions for the second de-separation include: a rotation speed of 5000-6000 rpm; and a time of 5-15 minutes.

Images