Plasma gasification

The plasma gasification is called the processing of waste of all kinds and decomposition in exhaust gases and ash using plasma. In this type of treatment, temperatures of up to 17,000 ° C. The organic components decompose and burn completely, mineral and metallic components are sintered to form a vitreous ash.

Operation

Two electrodes are placed under high electric voltage, resulting in rollovers. Therebetween is allowed to flow through air, which is ionized into a plasma. In their impact on waste material to be burned when it comes to the recombination of the oxygen and nitrogen atoms and so that a substantial temperature increase, obtained by the also inert compounds necessary for complete combustion activation energy. For generating the plasma, a large amount of electrical energy required. The method is therefore primarily intended for such hazardous waste, which is not fully implemented in ordinary incinerators. A similar method is used in arc welding.

According to a statement, the operator In this method produces no harmful emissions and it can be implemented in these plants of all kinds material, explosive and toxic, medical and (in small amounts ).

Criticism

By experts is disputed and doubted by critics that the process on an industrial scale works without any dangerous residues. From the exhaust gases furans and dioxins could under suitable conditions form. The composition of the slag and its harmfulness caused by heavy metals, for example, is also discussed.

History

The first plasma gasification plants for municipal waste were built shortly after the turn of the millennium. Hitachi, for example, began early on the technology of Westinghouse Plasma and operates since 2002 in the Japanese city Utashinai two systems, which are designed for a total of 300 tons of waste per day. Small plants for hazardous waste disposal existed even before that, the first plant was built in Australia in 1992. The process of the plasma arc was in the 1960s developed by NASA to test the heat shields of space shuttles, because conventional methods were not hot enough. Since then, many systems have been implemented around the world, with more planned. Most small plants for hazardous waste disposal such as an investment in the National Cheng Kung University in Taiwan, which operates a gas plant with a capacity of 3-5 tons per day, do not generate additional electricity, but save the cost of expensive disposal of the waste. In the complex in Taiwan, for example, medical waste, incinerator ash, organic waste, inorganic sludges, batteries, Schwermetallschlämme and refinery catalysts can be gasified. It was decided the construction in November 2004 and the plant was put into operation in January 2005.

Practice

One operated by Westinghouse since 2003, the complex had to be parked more often due to technical problems.

There are technological problems, such as the materials because of the high temperatures.

Due to the high investment costs and the untested technology, most systems are still not progressed beyond the planning stage.