Plasma gasification

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As plasma gasification refers to the processing of waste of all kinds and degradation in exhaust gases and ash using plasma . This type of treatment creates temperatures of up to 17,000 ° C. The organic components disintegrate and burn completely, mineral and metallic components sinter to form a glass-like ash.

functionality

Two electrodes are placed under high voltage , which causes flashovers . In between, air is allowed to flow through, which is ionized to form a plasma . When they come into contact with waste materials as fuel, the oxygen and nitrogen atoms recombine and thus a considerable increase in temperature, through which even inert compounds receive the activation energy necessary for complete combustion . A large amount of electrical energy is required to generate the plasma. The process is therefore primarily intended for hazardous waste that is not fully implemented in normal incineration plants . A similar process is used in arc welding .

According to the operator, this method does not produce any harmful exhaust gases and all types of material can be converted in these systems, including toxic, medical and (in small quantities) explosive.

criticism

It is disputed by experts and doubted by critics that the process works on an industrial scale without dangerous residues. Furans or dioxins could form from the exhaust gases under suitable conditions . The composition of the slag and its dangerousness, e.g. B. caused by heavy metals is also discussed.

history

The concept of plasma gasification of household waste was introduced in December 1973 by Dr. SL Camacho patented. In 1988, Resorption Canada Limited put a prototype into operation. In 1989, Ohio began operating the first steel industry industrial waste disposal facility. The first municipal waste plasma gasification systems were developed by Hitachi and Westinghouse in the 1990s. In December 1999, the first test facility was put into operation in Yoshii . Hitachi has been operating two plants in the Japanese city of Utashinai and near Mihama and Mikata since 2002, which are designed to handle a total of 300 tons of waste per day. The plasma arc process was developed by NASA in the 1960s to test the heat shields of the space shuttles because conventional methods were not hot enough. Since then, many systems have been implemented all over the world, and more are being planned. Most small plants for hazardous waste disposal such as For example, a plant at Cheng Kung National University in Taiwan, which operates a gasification plant with a capacity of 3 to 5 tons per day, does not generate any additional electricity, but saves the costs of expensive waste disposal. For example, the plant in Taiwan can gasify medical waste, incinerator ash, organic waste, inorganic sludge, batteries, heavy metal sludge, and refinery catalysts. The decision was made to build it in November 2004 and the facility was put into operation in January 2005.

practice

A plant operated by Westinghouse since 2003 had to be shut down several times due to technical problems.

There are technological problems, e.g. B. for the materials due to the high temperatures.

Due to the high investment costs and the untested technology, most systems have not yet got beyond the planning stage.

Web links

Individual evidence

  1. ↑ Masoud Pourali: Application of Plasma Gasification Technology in Waste to Energy Challenges and Opportunities , accessed May 17, 2014
  2. ↑ James G. Speight: The Biofuels Handbook . Royal Society of Chemistry, 2011, ISBN 1-84973-026-1 , pp. 461 ( limited preview in Google Book search).
  3. ↑ Proceedings of the 18th Annual North American Waste-to-Energy Conference: Plasma Gasification: Lessons Learned at Eco-Valley WTE Facility 11. – 13. Retrieved May 17, 2014, Orlando, Florida, USA, May 17, 2010.
  4. ↑ Anne E. Maczulak: Waste Treatment: Reducing Global Waste . Infobase Publishing, 2010, ISBN 1-4381-2611-5 , pp. 68 ( limited preview in Google Book search).
  5. ↑ PEAT: PTDR Plasma Gasification system, Waste to Energy System, Medical Waste Treatment, Bio Waste Treatment - Tainan, Taiwan - PEAT , accessed May 17, 2014.