Recycling of Tires - Report Example

A Research Report on Recycling of Tires Name Course Instructor Institution Date Table of Contents Table of Contents 2 Introduction 3 Research objectives 5 Literature Review 5 Tire recycling process 6 Ambient mechanical grinding 6 Pyrolisis 7 Cryogenic grinding 7 How tires are recycled in the leading countries 7 Recycling in the USA 7 Recycling in Japan 8 Recycling in Germany 9 Recycling in the United Kingdom 10 Tires and the environment 11 Impacts of tires on the environment 12 How tire recycling is important to reduction of waste, cleaning up of the environment, and the fight against climate change 15 Discussion 16 Recommendations and Suggestions 17 Conclusion 17 References 19 Abstract Cases have been reported of piles and piles of scrap tires lying out in the environment, looking abandoned and giving an indication of negligence. The reality is that tires have been abandoned and this could be attributed to the lack of knowledge on what to do with the tires after they reach their end of service. The threats posed by abandoned tires could only be talked about with nothing much to be done on that. Studies conducted by Lin et al (2008, 1162–1166) on some properties of tires (hydrophobic property) and their laboratory tests revealed that waste tire could be reused. The discovery of technology that could turn this potentially hazardous product into resources that are valuable has been a welcome relief to the environment and to the human population (Reschner, 2008). It led to the development of the scrap tire industry, where products are made from scrap tires and utilized. This scrap tire industry is regulation driven. It is due to regulations laid to tackle issues of environmental concerns that the industry was created. Governments are also keen to bolster the development of this industry by granting incentives to products of end markets. Laws on tire recycling were first put by the USA and Japan to address the hazards posed by scrap tires. This puts them at the leading end of the industry. Europe has been lagging in this sense but developments are first coming towards the tire recycling industry. The industry majorly depends on regulations and support given by the government. Introduction Recycling of scrap tire in most industrialized countries has developed significantly. Reschner (2008) estimates that in the USA, about 2-3 billion scrap tires are dumped in illegal piles and abandoned. This is the cumulative figure of scrap tire generation in about ten years. This trend is the same among EU member states. A publication by the Green Living Tips (2006) reported that in the USA, nearly 300 million tires get scrapped or are dumped yearly. This landfill deposit of tires is not desirable as light tires are likely to rise through the overload to the surface. Furthermore, charges are being imposed on landfill and the charges keep rising. In addition, many societies are lobbying for restriction of recyclable products like tires from landfills. This is because open air disposal of tires has proven dangerous and is not desirable. A stack of abandoned tires poses a great risk to public health and public safety. In the event of a fire breakout, it would be difficult to put out the fire and there would be intense air pollution through smoke. Furthermore, stagnant waters in the tires form a breeding ground for mosquitoes. As a response to the hazard posed by scrap tires, industrialized countries have developed legal guidelines to address the issue. The regulations laid down may vary in countries but the objective remains that of providing an environmentally friendly disposal, to limit amount of tires stored at a location and support the use of recycled products from tires. The USA and Japan were first to lay down laws to address these hazards and are even currently leading in rate of recycling. Although Europe has been lagging in this respect, implementation of European directives forced the European industry to speed up its growth in implementation of the laws. This research paper will discuss the issue of recycling tires and its importance for the reduction of waste, cleaning up the environment, and also the fight against climate change. The environmental aspect of tire recycling will be given its importance. Research objectives To provide literature on recycling of scrap tires in leading countries in the industry. To study some of the processes used in carrying out tire recycling. To indicate the importance of tire recycling to the environment and to the climate. Literature Review Different definitions can be given to scrap tire. According to Rubber Manufactures Association (RMA), a scrap tire is one that cannot serve its originally planned purpose any longer. This therefore keeps out tires that can be retreaded and those that can be used again. In Europe and Japan, retreaded and reused tires are considered as being scrap. This report will use the RMA definition of scrap tire. These scrap tires are usually measured either in units like millions, in weight (tonnes) or in passenger tire equivalents (PTEs). A typical passenger tire constitutes 47% rubber compound, 21.5% carbon black, 16.5 % steel and 5.5% fiber/ nylon. The rest of the composition is filled by additives together with other elements like sulphur. Tires have very high energy content too. A tire could have a net calorific value of about 32 to 34 million Joules per Kilogram. This value can be compared with that of other fuels in the table below. Fuel Calorific Value Oil 46,000KJ/ Kg Coal 26,500KJ/Kg General Industrial waste 16,000 KJ/Kg Straw 15,000 KJ/Kg Tires 36,053 KJ/Kg Source: Department of Trade and Industry, 1997 From the table, it can be seen that the calorific value of tires is comparatively high. This therefore gives them a function in energy production. In addition, scrap tires can be broken down mechanically and used to produce new products. Further, the carbon can be extracted and used to make activated carbon. Hydrocarbons from the tires can also be extracted and used to create diesel fuel, limonene and jet fuel/ kerosene. Besides, one can compost the fiber so that it can be used as filler or incorporated in cement for reinforcement. Tire recycling process According to the Reschner (2008, pp 8-9), some of the technologies exist for recycling of tires include the ambient mechanical grinding, pyrolisis and cryogenic grinding. Ambient mechanical grinding In this process, scrap tire is broken at ambient temperature. The tires pass through a shredder which will break them into chips. These chips will then be fed to a granulator that will break them further into tiny pieces as it removes fiber and steel during the process. Should there be any steel remaining, it will be removed by use of the magnetic technique while any fiber remaining will be removed by a combination of wind sifters and shaking screens. To obtain any finer particles of rubber, additional grinding can be done in secondary granulators and rotary mills at high speed. Pyrolisis Here, scrap tires are thermally decomposed in the presence of little or no oxygen with the aim of recovering original raw materials that were used in making the tire, for example carbon black, oil, scrap steel and hydrocarbon gases. Despite its proven technical viability, not many companies have deployed the use of this technique. Cryogenic grinding In this process, scrap tires are ground at temperatures close to -80º C. These low temperatures are achieved by use of liquid nitrogen. Exposure of the tires to these low temperatures makes them highly brittle and therefore they become easy to crush and break. This gives the process the advantage of low energy required as compared to the other processes. How tires are recycled in the leading countries Recycling in the USA The USA has the largest industry of recycling scrap tire in the world. The end markets for products derived from tires and tire-derived fuel is said to be most developed in USA. The rate of recycling has also risen up and this can be evidenced by the fact that in 2003, the generation of scrap tire was 290 million and of this, 233 million got recycled. Its industry structure involves collection of scrap tires from the consumers and handing them over to collectors. Processors will then get the tires from collectors before shredding it and passing the product over to manufacturers or to end markets for consumption, as shown below: Ambient processing is widely used in scrap recycling, although some bigger firms have facilities for cryogenic processing. Generally, recent trends favor the technology that shreds tires into smaller and uniform pieces that are steel free and free of fiber components. This has been found to be suitable to many consumers who prefer rubber without steel and the steel can be sold to another consumer. Machines that produce rubber that is 99% rubber-free have thus been developed. Factors that have favored this recycling industry include the support received from the government and the growth of the end markets. Government support is however not consistent across all states. In addition, tire derived fuel has been under intense scrutiny by environmental conservationists and this has prompted the development of regulations to favor production of other end markets (Tire recycling industry: A Global Review: USA, pp 29-42). Recycling in Japan According to Fukumori and Matsushita (2003), Japan generates nearly 1 million tons of scrap tires annually. Yet in Japan, land is perceived to be at a premium and there is no space for landfills. As a result of this, recycling is given extreme importance. It has therefore been one of the principal recyclers worldwide. Recycling rates are high in Japan, ranging at between 85-90%. In 2003, the amount of scrap tires recycled was 855, 000 tonnes and most of this chunk were exported. Besides the already high recycling rates, Japan is still trying to improve the rates further and even reach 100%. The most important application of Japan’s scrap tires is tire derived fuel although scrap tire exportation is on the rise. There are two sources of scrap tires in Japan: tire replacement by consumers who replace their old and worn out tires with new ones and tires from end of life vehicles, that is tires from vehicles that have reached the ends of their lives. These scrap tires are usually disposed off near dealers like car dealers, tire retailers and vehicle repair shops. The dealers will then supply to distributors. It is from the distributors that the producers will get the scrap tires. Some consumers like car, bus and truck companies always dispose their scrap tires straight to the distributors and not through dealers since there are higher volumes involved. In addition, tires that are from end of life vehicles are disposed off straight to the collection and processing firms. Japan mostly uses most of its scrap tires for fuel purposes while the rest of the scrap tires are exported. This is because there is a tight raw materials’ supply and the energy costs are very high, prompting this use of crap tires as fuel raw materials. Previously, scrap tires have highly been used for heat utilization especially in the cement industry. However, this usage by Japan for fuel has attracted pressure from the international community to reduce the green house effect and as a result, the use is declining. In addition to being used as a fuel, rubber that is reclaimed and powdered is also used by molded products and new tires plus other applications of rubber. Recycling in Germany Germany is the most industrialized nation among the European Union and has the best tire recycling record among other countries in the EU. It also generates a lot of scrap tires and recycles a majority them. The most essential end market product is tire derived fuel. In addition, there are no specific regulations that apply to scrap tires. Further, there are no specific organizations to coordinate programs of scrap tires. Owing to increased EU regulations, it is expected that the rates of recycling will continue growing and this will further be aided by the fact that the industry in Germany is well developed. The industry structure of scrap tires in Germany operates under the industry responsibility and the producer responsibility schemes. Under the industry scheme, the responsibility for recycling of scrap tires and its management is assumed by producers and other industry players. On the producer scheme, the responsibility for recycling of scrap tires is taken by producers. In both cases though, the expenses for collection of tires and recycling them is catered for by the consumers. By and large, tire retailers will collect scrap tires from the consumers and it is the collectors who will transport the scrap tires to the processors for them to be processed for end products. As recycling rates grow, it is expected that generation of scrap tires will also grow, although the rate of this growth is not comparable to other European countries. It is also expected that the replacement demand will go flat over the subsequent few years since the demand for automotive in Germany has been stagnant. Despite this, the demand for products from end markets is high and this keeps driving the recycling industry. Tire derived fuel and products constitute the main end products (Tire recycling industry: A Global Review: Germany, pp 51-52). Recycling in the United Kingdom The UK is second to Germany in scrap tire generation in the EU. Going by Tire recycling industry, a Global Review (pp 51-52), 450,000 tonnes scrap tire was generated by Germany in 2003. About 59 % of these underwent recycling. Popular end market products include products derived from tires and tire fuel. The UK is still striving to establish a viable industry for recycling scrap tires. Proper discarding of scrap tires is the responsibility of importers and manufacturers. In addition, there was a separate organization called Tire Recovery Association (TRA) which was formed to develop industry standards and to watch over the industry’s development. Disposal of scrap tires by consumers is done near garages and tire retailers and are then collected by collectors authorized by the government. The tires are then shipped to processors for processing based on end market requirement. For their operation, both the processors and collectors should have a permit and are required to register with the TRA. The key drivers for the recycling industry include the demand received from end markets and the regulations laid by the government and external regulations. Other than tire derived products like rubber that is shredded and granulated, together with molded products and tire derived fuel, some of the scrap tires are also exported. Most of it is exported to fellow EU countries. The rate of exporting is dependent on fluctuations of currency. Tire derived products also have a higher demand than tire derived fuel. Despite there being a regulatory body, the government prefers voluntary measures in recycling of scrap tire since it believes that this approach will be more effective. Tires and the environment Piles of scrap tires have generally not been categorized as being hazardous, but they pose an environmental threat, especially when pyrolitically decomposed by fire. Most scrap tires are usually disposed off in the open forming landfills. This is because tires are uncomfortable to handle and are equally difficult to be packed together. These tires usually work their way up the dumpsite over time and they have costly damages to the cover of the landfill. Despite this knowledge, a key portion of the present scrap tire generation will still end up in landfills. Miguel et al. (2002) note that in the USA, there was a ban on land-filling of whole tires and after the implementation of this ban, the tires are usually shredded or cut into pieces before being land-filled. Among the EU, a landfill directive was issued which also banned whole tires from landfills. A further directive was issued which required that by 2006, no tire should be landfilled. This called for development of new disposal ways before the implementation of the directives could take full effect. These new ways were devised with great urgency among EU member states. One of this ways was monofilling which was a variation of landfilling. In this case, mixing of scrap tires with other wastes is avoided and the tires are kept at dedicated and licensed place. Upon reaching its capacity, the monofill is covered just like it is done for landfills so as to minimize risk of fire and to prevent breeding of mosquitoes. Most countries have therefore worked to establish programs that have features such as licensing or requiring registration for haulers of scrap tires, processors and even some end users. They also have limitations on who can handle the scrap tires and some have requirements for financial assurance for handlers. All these are meant to facilitate friendly handling of the scrap tires for the tires to be friendly to the environment. Impacts of tires on the environment According to Clean Energy Ideas (2012), disposal of scrap tires has proved to be a threat to the environment. In the USA, it has been considered to be a major economical as well as an environmental issue. Even with the advent of tire recycling, it is purported that tires that were dumped over the last 40 years in the USA will still present safety and environmental hazards projected to last for some foreseeable future. It is these issues related to environment that have led to regulations being laid so as to try and curb the effects of tires on the environment. The main hazard that is associated with uncontrolled disposal and subsequent piling into large amounts of outdoor tires is the possibility of large fires which become very detrimental to the environment. Shane (1999) observes that in the event that a fire occurs, putting it off becomes extremely difficult. Instances have been noted where fires from large piles of tires have occurred and lasted for numerous months, and its fumes being seen from miles away. Such an instance is the tire fire that occurred in Stanislaus County, Carlifonia (1999), which lasted a whole month. A lot of resources have to be spent in putting out this kind of fire. EA (2008, pp 10-11) states that smoke produced from these fires has effects on activities such as farming and it also poses great health risks to the nearby people. In addition, tire burning results in production of large volumes of pyrolitic oil and the contact of this oil with fire further ignites the burning of the oil. Extinguishing this fire exposes the fighters to the intense heat and smoke that is generated. Controlling of the produced oil is also a challenge and the people as well as the environment are exposed to contaminants. The higher volumes of black and thick acid smoke are a total risk to health when inhaled. In addition, studies done on fire tires have shown emissions of considerable amounts of bezo(pyrene). This compound is reported to be a carcinogen. Other emissions like benzene which is also carcinogenic have been noted. This therefore raises serious environmental concerns. In the event that it rains during the fire, the combination of smoke and rain brings about some potentially hazardous compounds that contaminate both the environment and anyone who gets into contact. It is therefore evident that the emissions from tire fires pose a serious threat to both human and environmental health. Respiratory diseases could be acquired together with accumulation of carcinogenic compounds in the body (Environmental Protection Agency, 2012). Beside the fires, pile of scrap tires form breeding grounds for mosquitoes, snakes and rodents. Mosquitoes that carry diseases could find their place in such places and this will be a threat to humans. Areas that have warmer climates form a good breeding ground for mosquitoes that transmit encephalitis and even dengue fever. Such cases have been reported around areas that have large piles of scrap tires. The reptiles and rodents such as crocodiles and snakes can be harmful if they come to contact with humans during their movement. Morris and Stelpstar (2001) added that besides this, the piles also cause degradation of the land onto which they have been placed. This is because the tires cannot decompose and as result, the quality of soil is reduced. Furthermore, large piles of scrap tires are an eye sore. They do not present a good image to people passing since laying your eyes on a chunk of waste is not appealing. Studies done by Miguel et al (2002) have revealed that zinc metal usually leaches from tires. It further revealed that hydroids formed on tires and that the zinc was highly accumulated in the hydroids. Leaching was found to occur on the surface of tires that are exposed. This leaching is known to reduce the ability of soil to produce by drawing water away from it. How tire recycling is important to reduction of waste, cleaning up of the environment, and the fight against climate change One important aspect of tire recycling is the prospect of cleaning the environment and relieving it of space. Dumped scrap tires have been known to fill up space and it would be good to have this space available for other uses. In addition, reusing tires leads to a reduction in consumption of energy and subsequently increasing the recovery of energy. Averagely, the creation of a new tire requires about 22 oil gallons. On the other hand, retreading of the tire only requires 7 oil gallons. This means that retreading costs between 30-70 % less as compared to manufacturing of a new tire. The cost to the consumer is therefore reduced. Besides this, tires can be used as fuels in manufacturing processes, instead of using fossil fuels. This reduces the consumption of fossil fuels as the energy stored in the tires will be utilized. According to ISRI (2009), recycling of tires also helps reduce the amount of carbon footprint and this is a positive sign from the perspective of climatic change. ISRI (2009) reported that the carbon footprint on production of asphalt is 840 kg CO2e per metric ton. On the other hand, recycling of tires recorded a carbon footprint of 124 kg CO2e per metric ton. This reduction in carbon footprint indicates that recycling tires impacts positively on the climate. It is also imperative to note the importance tire recycling in terms of beautifying the environment through their use on artificial turf play grounds. Instead of dumping the tires, the products like rubber are used to modify playgrounds. In addition, they are used to make quite highways using rubberized asphalt and to for maintenance of landscape by controlling erosion. This can be achieved by using the tires form terraces. Other factors that are of importance in tire recycling include the reduction of risks posed to the environment. These risks include fire risks, reduced leaching effects on the soil and removal of tires from the soil giving the soil time to improve in its quality. Discussion The process of tire recycling follows a general trend that starts with collection of the tires from consumers and generators and then taken to the processors. It is the processors that will carry out the process of tire recycling. The end products are then distributed from the processors as either tire derived fuel, ground rubber applications or for civil engineering applications. Tire derived fuel finds its use in industries such as the cement industry, paper industry and can also be used in industrial boilers. On the other hand, ground rubber applications is found in asphalt that is modified by rubber and used in roads, sports and other playgrounds, manufacture of new tires and can also be used as animal bedding. Civil engineering applications include drain fields for septic systems, construction of landfills and their operation and can also be used as a sub grade for insulation of roads. Most countries have found it useful to recycle tires. This could be attributed to the importance that has been discovered and also to the regulations laid globally as a movement towards conservation of the environment. The USA has been known to be a leader in recycling followed by Japan. Other countries are also following suit. Various companies are also coming up with newer techniques and machinery that will facilitate recycling of scrap tires. This can be evidenced by the Australian researchers (from CSIRO and VR TEK companies) who recently worked to develop a new technique that will improve tire recycling by 50 % (Treehugger 2009). Generally, the tire recycling industry has been active in many countries over the past years. However, it is in different stages of development in various countries but the general indication is that recycling of tires has been favored among the countries. This can be seen from the effort by the countries’ regulations to come into force necessitating the development of the tire recycling industry. Countries have even gone the extra mile of giving incentives to industries that use products from scrap tire recycling. Recommendations and Suggestions Countries should support institutions carrying out research on developing newer techniques of tire recycling. This would enhance efficiency of the recycling systems available. In addition, techniques should be developed to ensure a continuous recycling technique, where tire derived fuel is used to run the machines that recycle other tires. In addition to this, the timing of regulatory being introduced to countries should be hastened in countries where the development of tire recycling is still premature. It is the regulations that limit the advancement of the tire recycling industry. The countries should also be given the necessary support by able organizations so as to efficiently trap this hidden process (Environmental Protection Agency, 2012). Conclusion Most countries seem to be embracing the need for tire recycling. This has led to the development of the tire industry. Efforts have also been made through regulations to further develop the industry. However, the generation of scrap tires might flat due to stagnation of automotive demand. This leads to the judgment that the industry is highly dependent on the automotive industry. In Japan, the rates of growth are likely to taper off because recycling rates are peaking and there are no significant stockpiles. References Clean Energy Ideas, 2012. Tire Recycling. Retrieved on November 25th 2012 from http://www.clean-energy-ideas.com/recycle/tire_recycling.html. Department of Trade and Industry, 1997. Ministry for the Environment: archived Publication: Average Calorific Values of Varying Fuels Including Tires. Retrieved on November 25th 2012 from . EA. 2008. Guidance for the Safe Development of Housing on Land Affected by Contamination, R & D Publication 66, pp 10-11. Environmental Protection Agency, 2012. Wastes Resource Conversation: Common Wastes and Materials, Scrap tires. Retrieved on October 10th 2012 from . Fukumori K. and Matsushita M., 2003. Material recycling Technology of Crosslinked Rubber Waste. Japan. Green Living Tips, 2011. Tires, Recycling and Our Planet. Retrieved on November 25th, 2012 from: Institute of Scrap Recycling Industries, Inc. (ISRI, 2007). Carbon Footprint of USA Rubber Tire Recycling: The Institute for Environmental Research and Education. Lin et al, 2008. Recycling waste tire powder for the recovery of oil spills. Resources, Conservation and Recycling 52. Miguel et al, 2002. The leaching of inorganic species from activated carbons produced from waste tyre rubber. Water Research, 36: 1939–1936. Morris J.F. and Stelpstar S.C. 2001. Curb inlet Storm Drain Systems for Filtering Trash and Hydrocarbons. USA. Reschner Kurt, 2008. Scrap Tire Recycling: A Summary of Prevalent Disposal and Recycling Methods. Berlin, Germany. Shane M. Daniel, 1999. “Westley tire fire”. Westley, Stanislaus county, California. Treehugger, 2009. New Technology Hopes to Boost Tire Recycling by 50%. Retrieved on November 9th 2012. From . Tire recycling industry: A Global Review. Irevna. Retrieved on November 25, 2012 from < www.irevna.com/pdf/Industry%20report.pdf>. Read More

The USA and Japan were first to lay down laws to address these hazards and are even currently leading in rate of recycling. Although Europe has been lagging in this respect, implementation of European directives forced the European industry to speed up its growth in implementation of the laws. This research paper will discuss the issue of recycling tires and its importance for the reduction of waste, cleaning up the environment, and also the fight against climate change. The environmental aspect of tire recycling will be given its importance.

Research objectives To provide literature on recycling of scrap tires in leading countries in the industry. To study some of the processes used in carrying out tire recycling. To indicate the importance of tire recycling to the environment and to the climate. Literature Review Different definitions can be given to scrap tire. According to Rubber Manufactures Association (RMA), a scrap tire is one that cannot serve its originally planned purpose any longer. This therefore keeps out tires that can be retreaded and those that can be used again.

In Europe and Japan, retreaded and reused tires are considered as being scrap. This report will use the RMA definition of scrap tire. These scrap tires are usually measured either in units like millions, in weight (tonnes) or in passenger tire equivalents (PTEs). A typical passenger tire constitutes 47% rubber compound, 21.5% carbon black, 16.5 % steel and 5.5% fiber/ nylon. The rest of the composition is filled by additives together with other elements like sulphur. Tires have very high energy content too.

A tire could have a net calorific value of about 32 to 34 million Joules per Kilogram. This value can be compared with that of other fuels in the table below. Fuel Calorific Value Oil 46,000KJ/ Kg Coal 26,500KJ/Kg General Industrial waste 16,000 KJ/Kg Straw 15,000 KJ/Kg Tires 36,053 KJ/Kg Source: Department of Trade and Industry, 1997 From the table, it can be seen that the calorific value of tires is comparatively high. This therefore gives them a function in energy production. In addition, scrap tires can be broken down mechanically and used to produce new products.

Further, the carbon can be extracted and used to make activated carbon. Hydrocarbons from the tires can also be extracted and used to create diesel fuel, limonene and jet fuel/ kerosene. Besides, one can compost the fiber so that it can be used as filler or incorporated in cement for reinforcement. Tire recycling process According to the Reschner (2008, pp 8-9), some of the technologies exist for recycling of tires include the ambient mechanical grinding, pyrolisis and cryogenic grinding. Ambient mechanical grinding In this process, scrap tire is broken at ambient temperature.

The tires pass through a shredder which will break them into chips. These chips will then be fed to a granulator that will break them further into tiny pieces as it removes fiber and steel during the process. Should there be any steel remaining, it will be removed by use of the magnetic technique while any fiber remaining will be removed by a combination of wind sifters and shaking screens. To obtain any finer particles of rubber, additional grinding can be done in secondary granulators and rotary mills at high speed.

Pyrolisis Here, scrap tires are thermally decomposed in the presence of little or no oxygen with the aim of recovering original raw materials that were used in making the tire, for example carbon black, oil, scrap steel and hydrocarbon gases. Despite its proven technical viability, not many companies have deployed the use of this technique. Cryogenic grinding In this process, scrap tires are ground at temperatures close to -80º C. These low temperatures are achieved by use of liquid nitrogen.

Exposure of the tires to these low temperatures makes them highly brittle and therefore they become easy to crush and break. This gives the process the advantage of low energy required as compared to the other processes.

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