|Product yields from the CAVD process. Click to enlarge.|
EarthFirst Technologies and Orion Industrial Services Corporation are working together on the final design, construction and commercial roll-out of a scrap tire recycling facility, known as the Catalytic Activated Vacuum Distillation Reactor (CAVD).
CAVD is a low-temperature pyrolysis process, in which scrap tires are thermally degraded in a vacuum at a third of the typical pyrolysis temperature, preserving tire components and satisfying even the strictest emissions regulations (as verified by Oak Ridge National Laboratories). The EarthFirst process relies on proprietary catalysts to convert tires at rapid rates.
From a typical 20-pound passenger tire, EarthFirst’s CAVD technology can recover nine pounds of carbon, for the manufacture of polymers; one gallon of oils, which can be used as fuels or industrial process oils; two pounds of steel; and 30 cubic feet of combustible gases to generate electricity.
Pyrolysis of rubber is an old concept. Rubber is treated at high temperatures in the absence of air to prevent oxidation. The long polymer chains of the rubber decompose at high temperatures to smaller hydrocarbon molecules. When the pyrolysis is performed under vacuum, the spectrum and quality of products obtained is distinct from the other (usually atmospheric pressure) pyrolysis process. The advantage of a reduced pressure is that secondary decomposition reactions of the gaseous hydrocarbons are limited.—C. Roy, H. Darmstadt, B. Benallal, A. Chaala and A.E. Schwerdtfeger, “The vacuum pyrolysis of used tires”, 1995
According to WESCO, the traditional problem with pyrolytic carbons produced from many competitive scrap tire recycling systems is a carbon product that has no significant market value. WESCO believes it has solved this problem through its proprietary process design and reactor.
EarthFirst built a full-scale, pilot CAVD Reactor in Mobile, Alabama in 2004. The “Green-Go” reactor has operated for more than 750 hours and has successfully deconstructed more than one million pounds of tire chips into recoverable by-products.
In 2003, more than 290 million scrap tires were generated in the US, according to the US Environmental Protection Agency (EPA.) Nearly 100 million of these tires were recycled into new products and 130 million were reused as tire-derived fuel (TDF) in various industrial facilities.
In TDF applications, scrap tires are typically used as a supplement to traditional fuels such as coal or wood. Used as fuel, tires produce the same amount of energy as oil and 25% more energy than coal. Ash residues from TDF may contain a lower heavy metals content than some coals, and TDF results in lower NOx emissions when compared to many US coals, particularly the high-sulfur coals.
EarthFirst argues that such combustion is a waste of a resource.
Tires should no longer be burned or buried because each tire contains more than 5 pounds of valuable carbon, over 40,000 BTUs of gas and 1.5 gallons of oil. WESCO’s CAVD process recovers these by-products using an estimated 5% of the energy while producing only 5% of the CO2 it takes to create virgin carbon black and oil products. Most significantly WESCO’s CAVD process has been certified by Oak Ridge National Laboratory as producing virtually no fugitive emissions.
EarthFirst’s tire process creates high energy gas and liquid fuels low in toxic polyaromatics, and a carbon black proven to substitute for blacks derived from petroleum. In addition to producing commercially viable products, the recovery of carbon black already present in tires allows for reductions in green-house gas emissions relative to virgin production methods.—Brad Mierau, WESCO VP of Operations
Last summer, EarthFirst’s new management in WESCO evaluated almost two years of data and discovered a previously disregarded carbon product and unused reactor technology. These were pursued with Orion, carbon customers and potential reactor customers and assimilated into an upgraded reactor design that should reliably produce readily saleable, commodity grade by-products. There are two pending patent applications covering WESCO’s initial and improved reactor process, technology and design.
In customer tests, WESCO’s CAVD carbon black has been successfully substituted for Series 700 virgin carbon blacks and the CAVD tire oil has been found to be similar to a #6 Residual Oil.
In May, Universal Textile Technologies committed to purchase a minimum of three million pounds of CP-200 Carbon per year produced via the CAVD process from WESCO. UTT will use the carbon in developing a proprietary carbon/polymer technology (with the primary building blocks from recycled tires and a renewable resource) that can be used in many different areas of the carpet industry.
WESCO’s CAVD carbon black product is produced consuming approximately 10% of the energy that it takes to make virgin carbon black. No CO2 is released in the production of WESCO’s CAVD carbon black, unlike virgin carbon black produced from petroleum or natural gas super-heating.
Under the terms of the joint venture agreement, EarthFirst’s WESCO subsidiary will contribute certain intellectual property rights relating to CAVD tire technology, use of the facility in Mobile, Alabama and up to $450,000 cash. Orion contributes certain intellectual property, construction and operational resources plus cash or cash equivalents of up to $850,000. Profits from the venture will be shared equally.
“The vacuum pyrolysis of used tires: End-uses for oil and carbon black products”; Authors: Roy C.; Chaala A.; Darmstadt H.; Journal of Analytical and Applied Pyrolysis, Volume 51, Number 1, July 1999 , pp. 201-221(21)