Thursday, January 8, 2015

Recycling of polymer wastes Almost all plastic products, carpets and synthetic textiles are made of

The use of waste as a resource in the community
The increasing production of waste as a result of our consumer society requires an increased focus on the development of sustainable processes colle that can transform waste into fuel, chemical raw materials and other useful products. Read the original article here
In Denmark, collected more than 14 million. tons of waste in 2005, of which industrial waste including include wastewater, paper, plastics, metals and chemicals account for about 75% [1]. Unsorted waste can not be recycled and must instead be burned or deposited, which can be a major environmental problem. Both in industry and in private households, we are too poor to sort and recycle our waste, and as an increasing need for more sustainable processes, we need to think more on reducing the amount of waste we produce.
Recycling of polymer wastes Almost all plastic products, carpets and synthetic textiles are made of polymers, which means that the polymer industry is an area where it really pays to make an effort to reduce colle and recycle waste products. Recycling of polymers can be accomplished by 1) conversion of the polymers to the other polymer products, 2) depolymerization of the original monomers, and 3) thermal depolymerization for the production of oil, petrol colle or diesel. Nylon 6 is used in textiles, carpets as well as various types of industrial colle plastic materials. In the US alone are landfilled annually 1.8 million. tonnes carpets consisting of nylon fibers. Nylon 6 is composed of the cyclic monomer caprolactam (Figure 1) and is one of the materials that we have the best technology for re-use [2]. Nylon 6 in the form of carpets into small pieces is fed into a reactor together colle with the superheated steam and H3PO4 at high temperature and pressure. This will degrade the polymer, and the resulting caprolactam vaporizes and can be isolated in over 99% yield. The resulting caprolactam can then be used to repolymerization for the production of new carpet or other nylon 6 products. colle The process can also be used for the extraction of caprolactam from other plastic and fiber waste, which is made of nylon 6. As a result of the effective colle recovery of caprolactam is nylon 6 products very valuable to society and important to recycle. After their lifetime of the consumer can be depolymerized and repolymeriseres to other products colle and thus in theory be a never-ending cycle of reuse without the generation colle of waste. A transformation of our technology to such materials colle that are sustainable, is therefore important to reduce the amount of waste. Soda Bottles of plastic is primarily made of PET (poly (ethylene terephthalate) (Figure 2), and the amount of waste in the form of such bottles worldwide is enormous [3]. PET bottles are recycled by thermal transformation, wherein said plastic is converted into new products such as non-food packaging polymer fibers in carpets and other fiber products. By thermal conversion cut the plastic material in small pieces, cleaned of impurities, after which the plastic during heat treatment formed into new packaging. PET bottles can also be depolymerized to monomers terephthalic acid and ethylene glycol, which like Caprolactam can be used again for polymerization. Since the structure of PET is more complex than nylon 6 (PET consists of two different monomers), colle the depolymerization does not have the same effectiveness are observed, but the resulting monomers may be separated and either sold to the chemical industry colle or used in the repolymerization other products. In Switzerland incorporated that up to 50% recycled PET in the production of new bottles, while many other places in the world only used about 10% [3a]. The aim is to PET bottles only be able to be made from recycled PET, and as a result of an increased colle focus on recycling and sustainability, Coca-Cola build a plant in the United States for recycling of PET from bottle returns. In the United States collected and recycled only about 25% of all soft drink bottles, and this is just one of the big problems with recycling plastic as the recycling industry has the capacity to recycle more than collected, but consumers are too poor to collect and sort their waste. Upon exposure of different plastics or biomass (eg. Abattoir) for high temperature and pressure, these can be converted to oil, petrol colle and diesel in a process that mimics the geological colle conversion of carbonaceous materials for fossil hydrocarbons. This will not degrade polymers colle to monomers, but to smaller hydrocarbons having up to 18 carbon atoms. These can be used as gasoline and diesel and light crude oil that can be included in classical oil refining and distilled into various petroleum products. By this process, the plastic and turkey waste, for example. colle is converted into oil, respectively. 70 to 39% yield and small amounts of natural gas (<20%) and charred carbon material and water [4]. Thermal depolymerization is a well known technique for recycling of the plastic during the formation colle of crude oil, but recently there b

No comments:

Post a Comment