NL1042095B1 - System and method for recycling expanded polystyrene - Google Patents

Abstract

A system for mobile recycling of expanded polystyrene EPS comprising a recycling machine for processing waste EPS, the machine is mounted on board of a vehicle, the machine has a feeding mechanism for automatically and autonomously feeding waste EPS to the machine. A shredder crushes the waste EPS into smaller pieces. The machine is arranged for processing the waste EPS in a stationary situation of the vehicle as well as in a moving situation of the vehicle. A preferred embodiment comprises that behind the shredder a compacter is arranged for at least partly compacting the smaller pieces. In order to minimize the moving around of waste EPS and in order to minimize unnecessary transport of air contained in the EPS in an efficient manner, the invented method proposes to collect waste EPS as close as possible to the place where the waste EPS is produced and process the waste while the vehicle is in motion.

Description

SYSTEM AND METHOD FOR RECYCLING EXPANDED POLYSTYRENE TECHNICAL FIELD

The invention relates to recycling of closed-cell foam materials. More particular the invention relates to compacting of expanded polystyrene (EPS).

BACKGROUND

Polystyrene foam, such as expanded polystyrene (EPS), has many industrial applications, for example as packing materials, cushioning materials, thermal insulation materials for buildings and refrigerators, roofing, decorative materials and so forth. However, such polystyrene-based products suffer from significant drawbacks such as uneconomical recycling as well as lack of biodegradability. Polystyrene foam, and especially expanded polystyrene foam, creates a recycling issue due to its low bulk density. Transporting polystyrene foam to a recycling plant becomes quite expensive, since polystyrene foam takes a lot of space per weight because of its low bulk density.

The waste polystyrene foam is transported, usually by truck, from one place to a waste facility. However, given the large volume of polystyrene foam and EPS relative to its weight, transportation becomes extremely inefficient (as only a fraction of the maximum weight capacity of the truck is utilized). This results in significantly more costs (fuel, time, etc.) in transporting the same weight of EPS as compared to regular waste. This inefficient transport leads to inefficient fuel consumption exhaust fumes such as carbon dioxide which in turn has adverse effects on the environment.

In order to reduce inefficient transport there is a need to reduce the volume (in other words increase density) of EPS before transport One approach comprises chemically reducing the EPS volume. However, there are significant drawbacks utilizing these chemicals as such chemicals can be very hazardous to human health and to the environment, as well as have storage, transportation and stability issues. For example, terpenes have storage and transportation issues because of their flash point and being highly volatile.

In the following, some example patents and patent applications are discussed which are aimed at recycling of EPS.

United States patent application US 2014/0031472 A1 by Rhodia Operations is summarized as a method for reducing the volume of polystyrene foam wherein a foam reducing agent is applied to the foam, whereby the foam reducing agent may comprise a branched dibasic ester blend.

Japanese patent application JPS6194705 (A) by Human Ind Corp. is summarized as a process wherein Polystyrene is heated to such an extent that it is not completely melted, shrunk down to 1/5-1/30 in volume and densified to a high grade. Then, it is crushed in a crusher. Modifier composed of inorganic material such as clay or aluminum hydroxide, etc. wood chips, rubber, plastics is mixed with granular or powdered polystyrene resin obtained. This mixture is pelletized by an extruder to recover the polystyrene resin.

Korean patent application KR 20140033936 (A) by Lee Jung is summarized as a method and an apparatus for reproducing used Styrofoam into polystyrene ingot pellets or foamed ingot pellets, using the following steps: collecting and washing used Styrofoam; crushing dried Styrofoam into particle materials; putting the crushed particle matters into a volume reducer so as to obtain a polystyrene resin; extruding and reprocessing rod-shaped polystyrene ingot into ingot pellets and bulk packaging the polystyrene ingot pellets.

United States patent US 5,664,491 by Harris Waste Management, Inc. is summarized as polystyrene baler for extreme compaction of expanded polystyrene or other similar materials where a ram forcibly acts to compress the expanded polystyrene material into a narrowing chamber where the narrowing chamber walls further act to compress the expanded polystyrene material to allow for air or gases trapped in the polystyrene material to escape so that a densely packed polystyrene bale is formed. A continuous bale is formed which can be broken or cut into desired lengths or weights. Vertically aligned walls of the bale chamber can be hydraulically actuated to accommodate the degree of compaction desired. A disadvantage of the current art solutions is that the process from becoming waste of the EPS to processing the EPS for further recycling lacks efficiency especially in the collecting of the waste EPS. This disadvantage is explained as follows. Collecting and processing of EPS is currently relatively expensive, especially in comparison with the price of the material and the value of waste EPS. Collecting and processing of EPS is moreover unpractical and causes environmental damage. One of the reasons of these disadvantages lies in the fact that waste EPS has a large volume in comparison to its weight because of the low density (typically 2% Polystyrene and 98% gas/air). When transporting EPS, one is in fact moving especially a large amount of air. EPS is widely used by local governments and companies, such as retail companies. For example, current collection methods comprise that waste EPS is contained in 1m3 bags, which are collected using truck and trailers.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a solution for collecting and processing of waste EPS which is efficient, clean, causes less environmental damage by reducing emissions of Carbon dioxide, particulate matter, nitrogen oxides. It is a further object to provide an innovative solution which is profitable for creating jobs.

These and other objects are realized by the present invention which is summarized in the following clauses. 1. A system for mobile recycling of expanded polystyrene EPS comprising a recycling machine arranged for processing of waste EPS, the machine arranged for being mounted on board of a vehicle, the machine further comprising: - a feeder arranged for temporary storage and feeding waste EPS to the machine; - a shredder arranged for crushing the waste EPS into smaller pieces; characterized in that, - the feeder is arranged for automatically and autonomously feeding the waste EPS to the shredder, whereby the feeder capacity does not exceed the capacity of processing and/or loading of the waste EPS by the shredder; - the machine is arranged for processing the waste EPS in a stationary situation of the vehicle as well as in a moving situation of the vehicle. 2. The system according to clause 1, characterized in that the machine further comprises a compacter arranged for at least partly compacting the smaller pieces with minimized impact on the waste EPS structure and/or arranged for compacting and pressing the smaller pieces into ingots of compacted EPS. 3. The system according to any one of the preceding clauses, characterized in that the feeder capacity does not exceed the capacity of processing and/or loading of the smaller pieces by the compacter. 4. The system according to any one of the preceding clauses, characterized in that the feeder comprises a conveyor with a front end positioned away from the shredder and a rear end positioned close to the shredder, the conveyor arranged for temporary storing and/or transporting a volume of the waste EPS towards the shredder. 5. The system according to clause 3 or 4, characterized in that the conveyor is arranged for storing and transporting of the waste EPS when packed in bags, said bags with the packed waste EPS arranged for being manually stacked on the conveyor, and said bags arranged for being manually removed from the waste EPS. 6. The system according to clause 4 or 5, characterized in that the feeder further comprises a chute, positioned on top of the shredder, whereby the conveyor is positioned adjacent to the chute, and whereby the conveyor is arranged for disposing the transported waste EPS into the chute. 7. The system according to any one of the preceding clauses, characterized in that the system further comprises a control unit, arranged for controlling the transporting of the waste EPS by the feeder, whereby a detection device, such as a laser, is arranged for detecting when the compacter has reached a load threshold, and whereby the control unit is arranged for halting the feeder until the load is sufficiently below said load threshold to further transport the waste EPS to the shredder. 8. The system according to any one of the preceding clauses, characterized in that the vehicle is further arranged for transporting of the waste EPS, the smaller pieces and/or the ingots, for the purpose of which the vehicle comprises a cargo compartment. 9. A method for mobile recycling of expanded polystyrene EPS, the method comprising the use of a recycling machine for processing of waste EPS, the machine arranged for being operated on board of a vehicle, the method further comprising: - using a feeder for feeding waste EPS to the machine; - using a shredder for crushing the waste EPS into smaller pieces, characterized in that, - the method further comprises using the feeder for automatically and autonomously feeding the waste EPS to the shredder, whereby the feeder capacity does not exceed the capacity of processing and/or loading of the waste EPS by the shredder; - the method further comprises using the machine for processing the waste EPS in a stationary situation of the vehicle or in a moving situation of the vehicle. 10. The method according to clause 9, characterized in that the method further comprises the steps of: - a control unit controlling the feeder to transport the waste EPS to the shredder. - the shredder shredding the waste EPS into smaller pieces; - the machine transporting the smaller pieces from the shredder to a compacter comprised in the machine; - the compacter at least partly compacting the smaller pieces with minimized impact on the waste EPS structure and/or compacting and pressing the smaller pieces into ingots of compacted EPS; - the control unit, upon detection of reaching a load threshold of the compacter, controlling the feeder to halt; - the control unit controlling the feeder to transport the waste as soon as the load of the compacter is sufficiently below said load threshold. 11. The method according to clause 9 or 10, characterized in that the method further comprises using the vehicle for transporting of the waste EPS, the smaller pieces and/or the ingots, for the purpose of which the vehicle comprises a cargo compartment. 12.The method according to any one of the clauses 9-11, characterized in that the method comprises that said vehicle is driven to a place as close as possible to the origin of the EPS waste production, whereby subsequently the waste EPS is collected and processed at said place and/or in the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures show views of embodiments in accordance with the present invention. FIGURE 1 shows an example embodiment of the present invention. FIGURE 2 shows an example recycling as used on board of a vehicle. FIGURE 3 shows the example embodiment to illustrate the process. FIGURE 4 shows an embodiment of the method according to the invention.

DETAILED DESCRIPTION

The invention is now described by the following aspects and embodiments, with reference to the figures. For easy reference of the numbers as used in the figures the following list is presented: 100 Present invention comprising a system such as a vehicle (e.g. a truck or trailer) with onboard shredding and compacting machine 200 Shredding and compacting machine, comprising a shredder and a compacter. The compacter is optional. 202 Chute (sheet plated cover) 203 Conveyor 204 Shredder 205 Motor and control unit 206 Compacter 207 Compacting tube 208 Press cylinder 300 Truck as an example vehicle 301 Cargo body 400 Power generator FIGURE 1 shows an example embodiment of the present invention 100, wherein a truck 300, as an example vehicle is provided with a cargo body 301 and a shredding and compacting machine 200 inside the cargo body 301 electric driven by a power generator 400. The truck may be driven towards a site where the waste bulk EPS is collected. Then the truck may leave for the next address to collect waste bulk EPS. Processing of the EPS may then be executed while moving. Alternatively, the truck may stay (for a while) in a stationary position while processing the EPS. FIGURE 2 shows an example shredding and compacting machine 200 as used on board of a vehicle 300. Bulk waste EPS is put into example vehicle via a hatch in the back door and falls into chute 202 on conveyor 203. Conveyor 203 is arranged for automatically transporting the pieces of waste EPS upwards towards shredder 204, where it is shredded into small pieces. Shredder 204 may be configured for example as two arrays of rotating teeth which are positioned opposite to each other, such that they overlap, but not touch each other when rotating in opposite direction such that the EPS is forced downward. The pieces of EPS are then crushed and shredded between the opposite teeth into smaller pieces. Shredder 204 is powered and controlled by motor and control unit 205.

Optionally, a mechanism for internal transport and compacting of the shredded EPS pieces forces the pieces into compacting tube 207, where the EPS pieces are compacted into ingots. A press cylinder 208 is arranged for pressing a press plate on the EPS to control the density of the pressed EPS, which allow for a very compact ingot, which has up to 90% less volume than the original bulk waste EPS. The ingots are pushed out of compacting tube 207 into the cargo space of cargo body 301, ready to be delivered at a different location.

When recycler request non compacted EPS (EPS structure is still complete and therefor can be recycled as EPS), the compacting and press cylinder will not be used but shredded EPS parts will be transported and stored in a storage room. FIGURE 3 shows the example embodiment to illustrate the process. The referenced numbers of the arrows are explained in the description of figure 4. FIGURE 4 shows an embodiment of the method 1000 according to the invention. The numbered steps are explained as follows: 1001 Start process

1002 Vehicle drives to location of bulk waste EPS 1003a Bulk waste EPS is put into hatch 201 of the vehicle 300 1003b Bulk waste EPS falls into chute 202 1004 Vehicle 300 moves or is stationary 1005a Feeding mechanism such as conveyor 203 feeds automatically and autonomously waste EPS towards the recycling machine 200 1005b Waste EPS falls into shredder 204 1006 Shredder 204 crushes waste EPS into smaller pieces 1007 Compacter comprising a transporting and compacting mechanism 206, and a compacting tube 207 is used for compacting the smaller pieces into partly compacted EPS or into ingots of maximum compacted EPS. 1008 Output of EPS ingots and stowing the ingots in a compartment of the vehicle 1009 Repeat from step 1001 or end.

In order to minimize the moving around of waste EPS and in order to minimize unnecessary transport of air contained in the EPS in an efficient manner, the invented method proposes to collect waste EPS as close as possible to the place where the waste EPS is produced. For example, a company having ordered packages which are delivered to the company wrapped in EPS, needs to get rid of the waste EPS. He invention advantageously proposes to collect the waste EPS at the site of that company.

Collection may occur on regular (for example weekly) basis, or by appointment. Our service comprises that a truck is driven to the company’s site and collects the EPS waste. The collected bulk waste EPS is transported into the truck at the site. The truck has an on-board machine which has a feeder and a shredder. The shredded waste EPS is much more easy to package efficiently in bags, considering that the bulk waste EPS usually varies very much in size and shape. Shredding leads to small pieces which are easy to handle and store, and take up less space than the bulk waste EPS.

In order to increase efficient packaging even more, a subsequent step of compacting may be applied. Compacting of the small pieces comprises that the pieces are compressed, which forces out a large part of the contained air and produces a smaller volume with a higher weight. For this purpose, a compacting machine may be arranged on board of the truck. This compacter is fed with the shredded ingots of the shredder. The compacter is arranged for at least partly compacting the smaller pieces with minimized impact on the waste EPS structure and/or arranged for compacting and pressing the smaller pieces into ingots of compacted EPS. Depending on the wishes of the client to whom the processed EPS is delivered, the EPS may be fully compacted or just partly compacted leaving the EPS structure intact as much as possible for reuse. Keeping the EPS structure intact also contributes to the object of the invention to recycle, i.e. reuse waste EPS in an efficient and clean manner.

After collecting of the bulk waste EPS, even before actual shredding, the truck may already leave the site and head for a next site where waste EPS is to be collected. While underway, the bulk waste EPS is fed to the machine and further processed. The packaged ingots (whether compacted or not) may be stowed away in the cargo space of the truck. Intermediate stops may be undertaken to drop of the packaged EPS, for example at a central collection site which has facilities for (further) compacting the waste EPS and/or recycling the EPS.

Especially when the feeding of waste EPS to the shredder is automated as is the case in the present invention, the feeding itself may be unattended while the vehicle is on the move. In order to make efficient use of the capacity of the elements of the recycling machine and to prevent overloading the control unit is arranged for controlling the feeder in dependence of various parameters which are detected by special detection means. The most important parameter which may be detected is the load of the compacter.

Usually the feeder, such as a conveyor may have sufficient capacity to load and transport waste EPS, and this transport may be started just before the vehicle is leaving. Consequently, the waste EPS is fed to the shredder, which usually is able to process relatively big loads of EPS. Nevertheless, in order to prevent the shredder form overload, the conveyor may be arranged such that the volume of waste EPS stacked on the conveyor physically cannot exceed the capacity of the feeder. The conveyor may be too small to hold too much EPS for example. More importantly, the compacter, giving the size of the invented machine which is limited by the size of a regular truck, has limitations in processing and loading of the shredded smaller pieces such as put out by the shredder. In order to detect if the compacter is near to a load threshold, a detector device may be installed which detects the level of EPS pieces in a compacting chamber which functions as a buffer and the entrance to the compacter. The detector device may for example comprise a laser which directs a light beam and detects the reflection. Whenever the EPS load is blocking the laser beam, the detector device may signal the control unit in order to (temporarily) halt the feeding process by the feeder. Other detector devices may be configured to detect jamming of various elements of the machine and subsequently ordering the control unit to stop the process.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that a person skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The term "and/or" includes any and all combinations of one or more of the associated listed items. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The article "the" preceding an element does not exclude the presence of a plurality of such elements. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims (12)

A system for mobile recycling of Expanded Polystyrene EPS comprising a recycling machine adapted to process waste EPS, the machine being adapted to be mounted on board a vehicle (300), the machine further comprising: - a supply device (203) arranged to temporarily store and transfer waste EPS to the machine; - a grinder (204) adapted to break down the waste EPS into smaller pieces, characterized in that - the supply device (203) is adapted to automatically and autonomously supply the waste EPS to the machine; - the machine is arranged both for processing the waste EPS in a stationary state of the vehicle (300) and in a moving state of the vehicle (300). The system according to claim 1, characterized in that the machine further comprises a compression device (206) which is adapted to at least partially compress the smaller pieces with minimal impact on the structure of the waste EPS and / or which is arranged to compress and compress the smaller pieces into blocks of compressed EPS. The system according to any of the preceding claims, characterized in that the capacity of the feed device (203) does not exceed the capacity of the waste EPS to be processed and / or loaded by the grinder (204) The system according to any of the preceding claims, characterized in that the feed device comprises a conveyor belt (203) with a front end that is placed away from the grinder (204) and a rear end that is placed near the grinder (204) ), the conveyor belt (203) being adapted to temporarily store and / or transport a quantity of the waste EPS in the direction of the shredder (204). The system according to claim 3 or 4, characterized in that the conveyor belt (203) is adapted to store and transport the bagged waste EPS, said bags containing the packaged waste EPS being arranged to be placed manually on the conveyor (203), and wherein said bags are arranged to be manually removed from the EPS waste. The system according to claim 4 or 5, characterized in that the feed device (203) further comprises a hopper (202) placed on top of the grinder (204), the conveyor belt (203) being placed next to the hopper (202) and wherein the conveyor belt is arranged to dump the transported waste EPS into the hopper (202). The system according to any of the preceding claims, characterized in that the system further comprises a control unit (205) adapted to control the transport of the waste EPS through the supply device (203), wherein a detection device, such as a laser, is adapted to detect when the compression device (206) has reached a loading limit, and wherein the control unit (205) is arranged to stop the supply device (203) until the loading is sufficiently below said loading limit, so that the transport of the waste EPS to the grinder (204) can be resumed. The system according to any of the preceding claims, characterized in that the vehicle (300) is further adapted to transport the waste EPS, the smaller pieces and / or the blocks, for which the vehicle (300) has a loading space (301) ) includes. A method for mobile recycling of Expanded Polystyrene EPS, the method comprising the use of a recycling machine for the processing of waste EPS, wherein the machine is arranged to be operated on board a vehicle (300), the method furthermore comprises: - the use of a supply device (203) for supplying waste EPS to the machine; - the use of a crusher (204) for breaking down the EPS waste into smaller pieces, characterized in that, - the method further comprises the use of the supply device (203) to supply the EPS waste automatically and autonomously to the crusher (204), wherein the capacity of the feed device (203) does not exceed the capacity of the waste EPS to be processed and / or loaded by the crusher (204); - the method further comprises the use of the machine for processing the waste EPS in a stationary state of the vehicle (300) or in a moving state of the vehicle (203). The method according to claim 9, characterized in that the method further comprises the following steps: - a control unit controls the feed device to transport the waste EPS (1005a, b) to the shredder; - the shredder grinds (1006) the EPS waste into smaller pieces; - the machine transports the smaller pieces from the grinder to a compression device included in the machine; - the compression device at least partially compresses the smaller pieces (1007) with minimal impact on the structure of the waste EPS and / or compresses the smaller pieces and compresses them into blocks of compressed EPS; - the control unit controls that the supply device stops as soon as it is detected that a loading limit of the compression device has been reached; - the control unit controls that the feed device resumes transport as soon as the loading of the compression device is sufficiently below said loading limit. The method according to claim 9 or 10, characterized in that the method further comprises the use of the vehicle (300) for transporting the EPS waste, the smaller pieces and / or the blocks to which the vehicle (300) a cargo space (301). The method according to any of claims 9 to 11, characterized in that the method further comprises driving said vehicle (300) to a location as close as possible to the origin of the production of the EPS waste, EPS waste is collected and processed on site and / or in the vehicle (300).