Solid waste treatment using plasma technology is an extreme thermal process using plasma which converts organic matter into a syngas (synthesis gas) which is primarily made up of hydrogen and carbon monoxide. A plasma torch powered by an electrical arc, is employed to ionize gas and turn organic matter into syngas with slag remaining as a byproduct.It is used commercially as a type of waste treatment and has been tested for the chemical action of municipal solid waste, biomass waste, industrial waste, hazardous waste, and solid hydrocarbons, such as coal, oil sands, petcoke and oil shale.
Small plasma torches typically uses an inert gas such as argon where larger torches require nitrogen. The electrodes vary from copper or tungsten to hafnium or zirconium, in conjunction with numerous different alloys. A high voltage with strong electric current is passed between two electrodes as an electrical arc and a pressurised inert gas is ionizing passing through the plasma created by the arc. The torch temperature ranges from 2,200 to 13,900°C.
The feedstock for plasma waste treatment is most municipal solid waste, organic waste include medicine waste and hazardous materials. Content and consistency of the waste directly impacts performance of a plasma facility. Pre sorting and utilisation useful material before gasification provides consistency. Too much inorganic material like metal and construction waste will increase slag production, that successively decreases syngas production. The benefit of slag is that it is chemically inert and safe to handle.Shredding waste before feeding the material into the main gasifier helps to increase syngas production this creates an efficient transfer of energy that ensures additional materials are broken down.
Pure extremely hot synthetic gas consists preponderantly of carbon monoxide gas (CO) and hydrogen(H2). Inorganic compounds within the waste stream aren't broken down however melted , which has glass, ceramics, and numerous metals.
The extreme temperature and lack of oxygen prevents the formation of the many toxic compounds like furans, dioxins, nitrogen oxides, or sulphur dioxide within the flame itself.
Metals resulting from plasma transformation are often recovered from the slag and eventually sold as a commodity. Inert slag made from some processes is coarse and may be employed in construction. A portion of the syngas produced feeds to a turbines, that power the plasma torches and so support the feed system. This is self-sustaining electric power.
The main advantages of plasma torch technologies for waste treatment are: