| Volume 4, | Number 1 | March/April 1996 |
NASA has teamed with a company to improve the process for recycling vehicle tires and turning them into material for building new roads and other useful items that benefit our everyday lives. NASA's Technology Transfer Office and engineers with Lockheed Martin Stennis Operations and Johnson Controls World Services, Inc., at NASA's Stennis Space Center in Mississippi have been working with Cryopolymers Inc., of St. Francisville, Louisiana, in freezing shredded tires and separating the rubber from reinforcing steel belts and polyester fibers. The next step in the process is to produce a material called "crumb," which can be used in asphalt road beds and other items.
"The Cryopolymers project is a prime example of how NASA technology and expertise can benefit the public," said Anne Johnson, NASA technology transfer officer at Stennis. "The results of such collaborations can create jobs, increase profits and enhance economic competitiveness for the United States."
Stennis personnel have been helping Cryopolymers incorporate cryogenics-the science of using super-cold fluids such as liquid nitrogen or liquid hydrogen-into its recycling process. Stennis utilizes 70 percent of all the liquid hydrogen used by NASA. As NASA's Center of Excellence for large propulsion systems testing, Stennis has expertise in the handling and application of cryogenic materials. Other expertise in instrumentation and measurement systems, as well as in automated computer control systems, was used in the manufacturing control process. Cryopolymers Inc. first learned of Stennis' capabilities through the technical assistance program at NASA's Marshall Space Flight Center in Huntsville, Alabama.
The most practical method of making "crumb" involves using liquid nitrogen to freeze the rubber to a temperature of -225 degrees Fahrenheit. Because the company has only been in operation for a few months, and the liquid nitrogen used in their process is extremely expensive, Cryopolymers was anxious to learn how to reduce the amount of nitrogen used. Stennis assisted the company in adapting its equipment to work in these very cold temperatures and make better use of the cryogens.
"Stennis personnel have been a blessing. The technology is there and we are purchasing equipment based on their recommendations," said Joe Kelley, director of community affairs for Cryopolymers.
The "crumb" that is created from the cryogenic process can be broken down into various grades according to particle size. Large particle crumb, which is the easiest material to process, is of less value and is typically used as a component to improve the wearability of a road surface. It also can be reprocessed to mold products that require little strength but must be weatherproof.
Fine crumb can be worth between 35 to 70 cents a pound and can contribute to making more expensive items, such as new tires and agriculture hose, or it can be mixed with plastics to produce culvert piping and bed liners for trucks. For each pound of rubber that is processed, approximately 60 percent is reduced into crumb. However, the scrap metal and polyester residue, called "fluff," also can be incorporated into new products as a reinforcing fiber.
The recycling of tires is beneficial in today's environmentally conscious society. The process not only has economic value, but also helps reduce the disposal problem of a worldwide production of more than 300 million tires per year. In addition, cryogenic recycling is safer than traditional methods of recycling. Cryopolymers is working toward reaching a production rate of 4,000 pounds of rubber per hour, which is more than 4,800 tires recycled a day. Cryopolymers Inc. has created 40 jobs and anticipates an annual income of $4 million.
NASA expertise in cryogenics is allowing Cryoplymers Inc. to recycle shredded tires more efficiently into "crumb," which can be used to create other products.
For more information, contact Joe Kelley at Cryopolymers Inc. Phone: 504/635-0092, Fax: 504/635-9153. Please mention that you read about it in Innovation.
