Patent Application
20140311886
The 1970's have proved to be a monumental time in the life of a scrap tire. That is when the United States became more interested in recycling in general. Prior to this time most tires were unwanted and piled up in our landscapes, buried or put in places where they'd be out-of-site. For many, the unwanted tires were an abundant resource. They were used for simple tire swings, barriers, landscaping and even barge operators thought they would be great to protect their boats. For the most part, before 1970 our nation generally didn't want the tires.
This uninterested position resulted in piles of tires building up all over our country. It wasn't until a few fires took place that the complications of massively piling these tires started to become noticed. Days often turned to months with some turning to years in what it took to put out these tire fires. The oil left behind acted as a fuel and putting out such fires became difficult. Then the oil took on a second hazard by seeping into the underlying ground making clean up even more cumbersome, costly and time consuming. In other parts of the country another disaster was taking place in the quiet vastness of our landscapes. Mosquitos and other insects found a new home. Breading grounds, like tire fires, became a public nuisance that affected cattle and human populations.
Since the 1960's our nation has been adding almost one tire per person equal to our country's population on an annual basis. This is just for passenger car tires. When commercial tires are added the numbers grow to over 425 million tires added to the piles each year. All of this has hit the news in recent decades and when the 1970's were upon us we became recycle conscious. All of a sudden the scrap tire became a valuable resource and there were plenty of them readily available. Like any first solution to a problem the simplest of application of science to a problem yields simple solutions. This lead to using the tires as a fuel source, the creation of landscape material making its way to playgrounds all around the country and crumb rubber, just to name a few.
Like most simple solutions, many jumped on the bandwagon and produced such products because of the ease of using a seemingly endless supply of scrap tires while also being able to take credit for being ‘environmentally green’. As time progressed the United States Environmental Protection Agency concluded that using the tires as a fuel source in cement and pulp plants produced too many harmful emissions. As of 2006 as many as 40 percent of scrap tires generated were being used as such a fuel. This use has been on a steady decline and is anticipated to be outlawed sometime in the near future. Like any first round of solutions second generation solutions we soon to come by a future round of improved applications of science.
The use of pyrolysis principles is beginning to surface eliminating emission issues and the creation of a whole breath of new off-take products. Two methods of utilizing retort fundamentals have surfaced. The first is called ‘continuous’ processing where scrap tires are cut up into 2-3 inch pieces, fed into a retort/furnace, heated to the point of decomposition without the aid of oxygen leaving carbon, steel, gas and oil. Alternatively, the second method is conducted in ‘batches’ where tires can be put in whole eliminating all upfront cutting and slicing costs. The tires are heated typically for longer periods of time versus the continuous processing machines producing an even higher level of off-take products with greater pricing capabilities. In conclusion, the public awareness of the values of scrap tires has improved greatly in recent decades and the conversion of such tires into valuable products is well on its way of the evolutionary cycle.
Examples of pyrolysis equipment are described in US patent publication 20060163053 and in U.S. Pat. No. 8,006,758.
What the general public is quite aware of is what is happening in the Powder River Basin area of Wyoming. Fifteen mines dig up coal for delivery throughout the United States to fuel electric power plants and a host of other uses. As the mining companies have driven the processes of extracting the coal to a high level of efficiency the solution has been based on one main principle: Make the trucks as big as possible to haul up to 400 yards of soil in a single load. All the mines have adopted the same philosophy as tires have grown from 10 feet in diameter to nearly 13 feet today and can weigh up to 7,000 pounds when discarded. These vehicles are used around the clock and generate between 4,500 to 5,000 scrap tires annually. It's important to remember the basic premise for which these tires are made. Their harsh use means they must be durable and built to be indestructible! The simple plys and bands of steel cables common in passenger car tires give way to steel cages and bead wire around the wheel hub up to 3″ in diameter. What is also common with all the mines is the inability to discard these large tires in a manner acceptable to the State's Department of Environmental Quality guidelines.
There has been extensive research and testing to slice, cut, chip and shred these behemoth tires without favorable results. The only formidable use of such tires over the past few years has been for cattle watering tanks They are created by ‘bagel cutting’ the tires, pouring a cement pad and placing the half cut tire on top of the cement filling the hub area of the tire. This has resulted in two problems. First, the need for water tanks has dwindled to a minimum as the market has become saturated and secondly, all of the top halves of the cut tires are piling up waiting for proper disposal. The lack of disposal solution for the mines has resulted in the remaining tires being buried. This singled out model of the coal mine industry in Wyoming is common throughout the world.
This invention addresses the problem of disposal of such large tires by utilizing the pyrolysis processes perfected over the past two decades in a batch mode to provide the first known method of acceptable disposal. As described above, the benefit of the batch process method is the ability to process the tires whole. The retort/furnace equipment required to conduct the decomposition of these tires is defined in this patent. It is unique to such comparable machines used to process passenger car tires to accommodate the massive 14,000 pounds of tires with the added benefit of having the capability to process small tires of all sizes as well.
The current method of recycling scrap tires involves slicing, chipping, burning and grinding. This is possible because the tires that average 22-24 pounds each are on a smaller scale than the equipment used to processes them. To expand the ratio of equipment capability versus tire size to handle a 7,000 pound tire is insurmountable. This is why the retort method utilizing pyrolysis processes is the emphasis of this patent. The ability to process the tires ‘whole’ decreases complexity, expense and creates an opportunity to process with repeatability in a safe environment.
A retort is an airtight vessel in which substances are heated for a chemical reaction producing vapor products to be collected in a collection vessel or for further processing. The retort in this patent is vessel approximately 13′6″ in diameter and 9′ in internal height that sets in a larger similar furnace vessel that contains numerous burners to provide the a heat source for the pyrolysis process to take place. The ability to remove the retort from the base furnace unit aids in loading and unloading to allow the furnace to be utilized around the clock. The retort/furnace vessel has the ability to capture the vapors given off by the heating of the tires for processing into oil and gas products. The retort/furnace contains a lid for containment of the heat applied by the furnace and directional flow of the vapors produced.
FIG. 2—retort/furnace Circulation Within The retort/furnace.
The retort/furnace consists of several components that collectively provide the environment to break down the tires being processed. The primary components include:
| Number | Date | Country | |
|---|---|---|---|
| 61754789 | Jan 2013 | US |
