TECHNOLOGY: Waste Meets the Plasma Waste Converter

William D. Siuru

Forget fossil fuels, the age of the hydrogen economy could be around the corner.

Today, hydrogen fuel cells are being developed for trucks, cars, buses, homes and small business.

Startech Environmental Corp., Wilton, Conn., owns a technology that could produce hydrogen from non-hazardous and hazardous waste materials including municipal solid waste (MSW). The Hydrogen Selective Membrane System can separate hydrogen from synthesis gas called Plasma Converted Gas (PCG), which is produced by Startech's Plasma Waste Converter (PWC).

The PWC process doesn't combust waste like an incinerator. Instead, the plasma, an electrified gas, is discharged within the PWC chamber. The continuous arc produces temperatures as high as 30,000 degrees Fahrenheit. The energy within the plasma excites the waste material's molecular bonds so that the material separates into its atomic components.

Once this dissociation occurs, the atomic components can reform into recoverable, saleable, nonhazardous commodities. This process can be used for solid, liquid and gaseous wastes, including hazardous and nonhazardous wastes, organic and inorganic solids, bases, and aqueous and non-aqueous liquids.

The PWC processes wastes so that they can be recovered in phases. Outside of producing hydrogen, the PWC produces PCG, which can be used as chemical feedstock to produce polymers and other chemical products. PCG also can be used as clean fuel to produce electricity, desalinate sea water or heat buildings.

Depending on the waste feedstock, other commodity products can be processed. For example, if the wastes contain sufficient metallic materials, these will collect in liquid form. Inorganic, glass-like silicates form a separate layer with small quantities of metal encapsulated in the silicate stone. These ceramic-like silicates can be used as quality aggregate material, and in the abrasives industry.

Startech's system does require electricity to create the plasma. However, when feedstocks rich in energy are processed, the PWC is a net energy producer. Each unit of electrical energy used to process wastes yields approximately four units of energy recovered with synthetic PCG gas.

PWCs also reduce the waste's volume by an approximately a 300 to 1 ratio.

Testing demonstrates that the PWC's performance is safer than United States and Canadian environmental standards. For example, the PWC remediates dioxins 12.5 million times safer than the U.S. Environmental Protection Agency's anticipated new standard of 30 nanograms per cubic meter of air.

Startech says the PWC can process waste at 8 cents to 11 cents per pound, including capital and financing costs plus other operating expenses such as consumables, labor, spare parts and electricity.

Startech's first commercial system is operating at the U.S. Army's Aberdeen Proving Ground, Md., processing up to 7 tons per hour. The company also is installing facilities in Taiwan, South Africa and Japan.