Power Plants Convert Tires To Energy

Every year, a vast quantities of vast tireswas discarded, which represented a tremendous amount of available energy hasbeen wasted. This potential is wasted when the tires are landfilled, taking upvaluable space and posing environmental concerns.

As an alternative, converting tyres toelectricity has greatly increased in recent years, and is likely to continue.This includes tyre-fueled power plants in Connecticut, Florida and Illinois.

A tyre-to-energy power plant in Sterling,Conn., went on-line in 1991. The 30-megawatt Exeter facility is fueled by wholetyres. The plant consumes 23,000 tyres per day, or 288 tons, in twin boilersthat supply steam to a 30 megawatt turbine generator. The 40-megawatt RidgeGeneration Station in Polk County, Fla., burns both shredded tires and woodwaste.

By 1996, a third facility is expected toopen in Ford Heights, Ill., about 30 miles south of Chicago. Most tyre-to-energyfacilities mix the shredded tires with coal, oil, wood or other fuels beforeburning them. However, the Ford Heights facility will use a tire-fired boilerwithout any additional fuel. The steam produced will drive a double,uncontrolled extraction, condensing steam turbine which is mated to asynchronous generator. At an optimum, the boiler will burn just over 16,500pounds per hour of shredded tires with a higher heating value of 14,500 BTUs-per-pound.Among commonly used fuels, only oil has a higher energy value.

Estimates show that the $105 million FordHeights waste tyre-to-energy project will produce 19.9 megawatts of electricalpower, most of which will be sold to Common-wealth Edison in Chicago. This quantityof energy could serve about 16,500 U.S. households; a small portion of theelectricity generated will power the plant itself.

In the process, the facility will consume65,000 tons of tires annually. This equates to 6.5 million passenger car tires,about 30 percent of the scrap tires discarded in the Chicago area.

In addition to the electrical energy,incinerated tire scraps will produce by products that can be reused by otherindustries. These non-hazardous materials include steel, zinc oxide and gypsum.

The Ford Heights facility should be completewithin two years. It is a joint venture between Houston Industries Energy Inc.and Chewton Glen Energy Inc., San Antonio. The Illinois facility will usecombustion boiler equipment similar to that at the Exeter and Ridge GenerationStation facilities.