Archive for the ‘ Plastic recycling ’ Category

There are four main waste reduction options for EPS packaging:

1. Reduce – refers to the reduction of natural resources used. By optimising pack design, moulders can reduce EPS usage, thus reducing environmental burden and cost.

2. Re-Use – EPS packaging can be re-used as multi-trip packaging, e.g. for the internal transport of partially assembled goods. Another simple re-use of the packaging is to grind it and use it as soil conditioner to improve drainage and aeration. EPS seed and pot-holding trays are often re-used in this way at garden centres.

3. Recycle – is the reprocessing of used EPS packaging to make a new material such as hardwood replacement for making garden furniture, slate replacement for roofing tiles and new plastics items such as coat hangers, CD and video cases

4. Recover – EPS has a very high calorific value, higher than that of coal, and can be safely burnt within energy recovery units, or incinerators, without giving off toxic or environmentally damaging fumes

Jun
02

Before you can recycle plastic items, you need to wash and separate them based on the resin identification codes printed on the bottom of every plastic product. Two of the most easily recyclable plastic types are PET, used to make plastic beverage bottles, and HDPE, used to make containers for milk and plastic bags. They have the resin identification codes 1 and 2. Recycling facilities, however, accept different types, so ask what types of plastics you can recycle in the facility closest to your home. In many facilities, plastic beverage bottles such as water, juice and soft drink bottles are redeemable for cash. Remember to remove the caps from the bottles before recycling because most of the time the caps have a different resin identification number than the bottles. Today, many grocery stores also have Waste plastic recycling for plastic grocery bags.

After 1970, plastic prices rose again due to OPEC raising the cost of petroleum feedstocks and recycling practices again increased. Interest increased not only in processes for reclaiming waste plastics, such as product evaluation for chemicals and fuels, but also in the necessary step of separation of plastics from other waste material. A review of this early history of plastics recycling is given by R. J. Ehrig in Plastics Recycling, Oxford University Press, NY, 1992, hereinafter referred to as Ehrig (1992). Some of the early operating plants for recycled plastic included a Department of Energy funded plant in LaPorte, Tex., which used a fluidized bed of sand and was designed for 17 million pounds per year of atactic polypropylene. It ran from 1980-82. In 1984 at Ebenhausen, Germany, a 20 million pound per year plant used molten salt with a fluidized bed reactor to process plastic wastes and tires.

The biggest advantage in plastic recycling machines is the need to produce new plastic items is reduced. Oil is one of the components used to make plastic, so decreasing the need will conserve non-renewable fossil fuels, reduce energy consumption and reduce CO2 emissions. In addition, plastic products are bulky and do not decompose in landfills, so recycling them reduces the amount of solid waste going into our landfills.There are many different types of plastics with several resin identification codes, but only the same type of plastics can be recycled together. Separating different types of plastics can be confusing and not all types are accepted in all recycling facilities. Because of this, new technologies are needed to make some plastic types recyclable. Until these technologies are developed, many plastic products will remain unrecycled. Instead, they are taken to landfills, being incinerated or shipped to foreign countries for recycling. Everyone of us needs to change our consumer habits and that is not an easy task. Using a canvas bag at the grocery store, not purchasing new plastic containers but reusing the ones you already purchased and recycling your plastic beverage bottles are actions we are still learning.

In all cases economics governed whether such plants continued operation. Since 1985 plastic recycling line has become more economically feasible due to continued plastics technological growth and increased environmental concern, however, significant cost impacts remain due to the level of the elevated temperatures previously required.The first two steps in recycling plastics are sorting and separating. After this, each plastic type is either melted down and molded into a new shape or shredded into flakes and then melded and processed into granulates. What is made out of the recycled plastic determines which recycling process is used.

Jun
02

A process for recycling or decomposing waste plastic where such plastic recycling line is decomposed in a diluent such as hot oil through actions involvingfree radical precursor, such as polyvinyl chloride or polyurethane, is achievedat low temperature. The thermal decomposition (or pyrolysis) reaction is forabout 1 hour at 375° C., and useable products, such as distillate, coke, and oilare recovered. Additionally the diluent may be recycled within the process.

When plastic is Waste plastic recycling , it goes through a process of using scrap or waste plastic and then reprocessing the plastic into useful products, sometimes even into something that does not resemble anything its original form. Every year, an estimated 13 billion plastic bottles alone are thrown away but only 2.7 billion of them are recycled. However, if you recycle one plastic bottle you are actually conserving enough energy to light a 60W light bulb for six hours, reducing the world’s dependency on oil and decreasing CO2 emissions caused by use of fossil fuels.

The present invention relates generally to processes for low temperature thermal decomposition of waste plastics. Specifically, the invention focuses upon achieving decomposition of waste plastics at a lower temperature than was previously possible. In particular municipal, health and industrial waste plastics are processed such as (but not limited to) polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polyurethane (PU), and polyvinyl chloride (PVC).Plastic is most often used to make bottles for beverages, containers for food, plastic grocery bags, furniture and many other common items we all use every day. Plastic waste takes about 11 percent of our household waste and 40 percent of that waste is plastic bottles. plastic recycling line can be used in many different ways, some of them less than obvious. Besides just using recycled plastic to make new plastic items such as bottles and garden furniture, recycled plastic is also used to make fleece clothing and fiber filling for sleeping bags.

Waste plastics, that is synthetic polymer-containing substances, pose an environmental issue because of the problems associated with disposal: a large volume of non-biodegradable material. Because of the limits on landfill capacity, future recycling or decomposition is a necessity. Direct recycling back to the manufacture is not always feasible because such waste plastic is often mixed with respect to polymer type and separation is uneconomical. Economical considerations for processing waste plastic often require the use of the unseparated mixed waste plastic. plastic recycling machines originated with the manufacture of synthetic thermoplastics. Rejected parts, trim, and flash from operations represented valuable materials that were ground and recycled with virgin material. This process was potentially repeated a number of times provided the percentage of regrinds remained low. As long as the plastic scrap generated by the industry was clean and uncontaminated with other plastics, reprocessing within the industry continued to expand, provided the price of virgin plastic remained high. After 1960 with a decrease in prices, profit margins for plastic scrap were squeezed, and disposal instead of reprocessing often occurred.

May
06

Plastic recycling by the plastic recycling line is the process of restoring scrap or waste plastics and reprocessing the material into useful products, sometimes completely different from his original state. For example, it could mean the merger of the soft-drink bottles after casting and plastic chairs and tables. Typically, a recycled plastic is not in the same type of plastic and recycled plastic is often recycled.
Compared with other materials such as glass and metal, plastic polymers require greater processing for recycling. [Edit Plastics] have a low entropy of the mixture, which is due to the high molecular chains of polymers by weight. A macromolecule interacts with its environment along its entire length so that its enthalpy of mixing is large compared to that of an organic molecule with a similar structure. Heating alone is not sufficient to resolve a larger molecule, because of this, plastics must often have almost identical composition to mix effectively.

Waste plastics or polymers with synthetic substances pose an environmental problem due to problems associated with the disposal are: a large quantity of non-biodegradable. Due to limitations in the capacity of landfills, is the future of recycling or degradation is a necessity. Direct recycling back to the manufacturing sector is not always possible because of the plastic waste is often mixed in the nature of the polymer and the separation is not viable. Economic considerations for the treatment of plastic waste often require the use of mixed plastic waste without segregation. Recycling of plastics by plastic recycling line from the manufacture of thermoplastic synthetic fibers. Rejected parts, registered and flash operations represented precious materials were crushed and recycled with virgin material.
This process was repeated several times to sharpen the established power remains low. As plastic waste by the industry was clean and not contaminated with other plastics reprocessing industry continues to grow, provided that the price of virgin plastic is still high. After 1960, lower prices, profit margins have been squeezed for waste plastic and waste instead of reprocessing more frequently.

When different types of melted plastic, they tend to separate provision, such as oil and water, and put in these layers. The phase boundaries cause structural weakness of the resulting material, so that the polymer blends means of limited use for recycling applications.Another obstacle is the widespread use of dyes, additives and other additives in plastics. The polymer is generally too viscous to economically remove fillers, and are used by many processes that could cheaply remove the added dyes affected. Additives are used less frequently in beverage cans and plastic bags, so they use more recycled frequently.The of biodegradable plastics is increasing. If these products are mixed in the plastic recycling line , plastics are not recycled are recovered, since different properties and melting temperatures.
After 1970, prices rose again in plastic, because the OPEC to increase oil prices and raw material recycling practices again increased. The increased interest not only in the recovery process of plastic waste, such as the assessment for chemicals, and fuels, but also the necessary step of the separation of plastics from other waste. An examination of this story at the beginning of the recycling of plastics is given by RJ Ehrig plastic recycling, Oxford University Press, NY, 1992, hereinafter, Ehrig (1992). Some plants are in operation at the beginning of the recycled plastic contains a power station by the department in LaPorte, Texas, funded with a fluidized bed of sand and was designed for 17 million pounds per year of polypropylene atactic. It ran from 1980 to 82 In 1984, Ebenhausen, Germany, 20 million pounds per year for the use of plants with molten salt, fluidized bed reactor for the treatment of waste plastics and tires.
In all cases in relation to the economy if these systems operate continuously. Since 1985, plastic recycling machinery has become concern profitable growth because of the engineering plastics and continue growing environmental problems, however, remain a major impact on costs due to high temperatures than previously required.

1.Choose goods with minimal packaging, and which are packaged in a material that can be recycled or returned in your area.
2.Try to reduce the need to throw away plastics. For example, take a reusable shopping bag to the supermarket or corner shop, or re-use the bags you were given last time. Don’t accept a bag if you don’t need one. When they are beyond reuse, plastic carrier bags can be put into collection banks at some Morrisons, Tesco and Sainsbury’s supermarkets.Rather than throwing them away, give plastic toys or containers to children’s scrap stores or playgroups for reuse. Further details can be found here
3.Use plastic containers and bags again or make them into something else. For example use yoghurt pots to grow seedlings, use the top part of drinks bottles as cloches for plants and offer clean plastic carrier bags to charity shops.
4.Buy products that are refillable.
5.Think of ways of reducing the need for packaging. Don’t add extra packaging yourself - a melon, a grapefruit or a bunch of bananas already has natural packaging - does it need to go in a plastic bag as well as your shopping bag, and does that already efficiently packaged dairy product or piece of meat really need another wrapper?
6.Ask your local authority recycling officers which materials are currently collected or may be collected in the future.
7.Look for products, e.g. bin liners and refuse sacks, made from recycled plastic, now available in many supermarkets. Also look out for products packaged in at least partially recycled material. For example, Shell Oil’s 1 litre and 4 litre Helix oil packs now contain a proportion of recycled plastic, collected from domestic and industrial waste.
8.If it does not already run one, suggest to your local authority that it considers starting a plastics recycling scheme. The development of market opportunities has meant that at the moment demand is outstripping supply of plastic bottles, so new initiatives are needed to feed the process and ensure its success.
9.Encourage your local authority to buy products, such as street furniture, made from recycled plastic rather than wood.
10.When you put plastic bottles in plastic bottle recycling machines, or even in your bin, ALWAYS REMOVE THE BOTTLE TOPS.  This also enables them to be crushed more easily so they occupy less space.

Reference:http://www.wasteonline.org.uk/resources/InformationSheets/Plastics.htm

Drying, together with cutting, is one of the difficult step of any plastic recycling machines.

Drying is easy when talking about thick flakes of any plastic material.

For example drying HDPE flakes from plastic drums is the easiest job in this world because thickness is in the range of two or three millimeters, the material is elastic so you can put it into any spin dryer and you get them dry.

The matter becomes a little different when happening to thin flakes out of a film line, and for thin around 20 microns (of millimeter) or less, or brittle materials like Polystirene, PC, etc.

Let’s see one problem at a time.

This film first.

If your centrifugal dryer leaves one milligram of water per square centimeter (or change the units but the general concept remains) and your flakes weighs one gram, moisture content will be 0,1% and everybody is happy.

Because the centrifuge performs the same way, doesn’t matter the thickness of your flakes, the same one milligram of water per square centimeters means 10% if the flake weighs 0, 01 gram.

Most of everybody uses hot air for final drying, and because hot air cost a lot of energy, one matter is to start from a moisture content of 2% and a completely other one is a10% starting point.

So, before sizing the hot air drying system, you better care about the % of moisture out of your dryer, whatever it is.
We do love centrifuges for quite many reasons:
First is the fact we can get very low moisture content, even with very thin materials, and very proud of this.
Second because any centrifuge, while drying, it washes as well because it is the combination of friction with water presence.
Third because even the most sophisticated centrifuge is nothing but a rotor spinning into a screen basket that means it is an easy to maintain machine and cannot give lots of problems.
So, as far as today, the very best way we know to get plastic flakes dry, is to go with a well performing centrifuge.
Centrifuges can be very different and the one that makes thin film dry will make 30% fines running Polystirene so diameter, shape of the paddles, size of screen holes and may be something else should change accordingly.
After getting flakes mechanically dry, for some plastics, we will need further drying to get the best possible quality.
We’ll talk about Crystalline Polymers later in this chapter because they need something very specific.
For all other polymers, what we do suggest, is to get a good extruder with a venting, better with two, and feed it straight with the flakes you got after the centrifuge.
This what we do in all cases but one; dealing with film, doesn’t matter the thickness, washing and drying is done with flakes of about 30-40 mm. in size and any force feeding (we know of) accepts only way smaller flakes so further cutting is needed.
Because any granulator will make friction by cutting, meaning developing heat, and then, by blowing, flakes lose some more humidity and by the time they get to the extruder, will be dry enough for pelletizing.
Crystalline Polymers, as we said, need a chapter by its own
PET and PC in fact don’t like the mixture of water (moisture) and heat together plus the fact they are hygroscopic by themselves. (PA performs the same way even not being crystalline)
So if you dry and leave them in a storage place they will get moisture from the air and the energy you have been using to dry them is just thrown away.
Drying should occur just before extrusion and moisture content is measured in PPM and not a %
Both material need a dryer where they stay for sometimes (few hours) with or without vacuum and this because they should release the moisture that’s inside the flakes, or pellets
If these polymers are not completely dry, during extrusion IV (Intrinsic Viscosity) will decrease a lot and polymer loses its characteristics.
Mechanical drying at the end of the pp film drying line should deliver a flake with a moisture content of 0,5-0,6% and after this it will be a dryer unit job to decrease it to nothing (a good dry flakes should have 20 PPM before extrusion)

Plastic Classification

Author : admin
Dec
25

There are about 50 different groups of plastics, with hundreds of different varieties. All types of plastic are recyclable with plastic recycling machines.

To make sorting and thus recycling easier, the American Society of Plastics Industry developed a standard marking code to help consumers identify and sort the main types of plastic.

These types and their most common uses are:

1.PET - Polyethylene terephthalate - Fizzy drink bottles and oven-ready meal trays, peanut butter jars . PET types can be recycled by PET bottle washing line.

2.HDPE - High-density polyethylene - Bottles for milk and washing-up liquids, motor oil HDPE types can be recycled by PE granulating line.

3.PVC - Polyvinyl chloride - Food trays, fast food service items and shampoo, cooking oil bottles

4.LDPE - Low density polyethylene - Grocery bags and can liners.

5.PP - Polypropylene - Margarine tubs, microwaveable meal trays, bottle caps, yogurt containers, straws. PP types can be recycled by PP granulating recycling line.

6.PS - Polystyrene - foam meat or fish trays, hamburger boxes and egg cartons, vending cups, plastic cutlery, protective packaging for electronic goods and toys (packing peanuts).

7.OTHER - Any other plastics that do not fall into any of the above categories. - An example is melamine, which is often used in plastic plates and cups.