The innovative and patented core Plasma Thermal Destruction & Recovery waste to energy solution is a gasification technology. Gasification is a process that converts organic based carbonaceous materials into carbon monoxide (CO), hydrogen (H2) and carbon dioxide (CO2) by reacting the material (i.e. waste) at high temperatures (minimum 700°C) without combustion with a controlled amount of oxygen and/or steam. The resulting gas mixture is called syngas (from synthesis gas) and is itself a fuel.
PEAT uses the heat generated by plasma-arcs to first pull apart (dissociate) the molecules that make-up the organic portions of the waste, then, depending on the composition of the waste stream, oxygen is added to reform the dissociated elements of the waste into the syngas The syngas can then be used in a variety of ways: as a fuel for thermal and/or electricity production or as a feedstock for the production of liquid fuels, such as ethanol.
Waste, when heated to a very high temperature in the controlled atmosphere of the reducing plasma reactor undergoes predictable physical and chemical changes. This high temperature, over 1,250°C (2,280°F) prevents the formation of complex organic molecules and breaks down organics into a gas. Our operations reflect that the formation of dioxins or furans is practically impossible inside the plasma reactor due to the unique process features, including high uniform temperatures and a lack of excess oxygen within the system.
This hot gas is then fed through a gas cleaning and conditioning system (The gas that comes out of a plasma reactor has a trace of contaminants compared to huge quantities in the stand-alone incinerator), where it is rapidly cooled and cleaned to remove any entrained particulate and/or acid gases prior to potential re-use.
Any inorganic constituents of the waste are melted (vitrified) into an environmentally safe, leach resistant, glass matrix. Plasma Thermal Destruction & Recovery waste to energy plasma reactors are designed to collect the molten metal and glass. The glass and metal layers are removed through controllable tap ports into a slag/metal collection system. Removal of the molten glass or metals presents no hazards of any kind to personnel, requires no special tools and does not disrupt the operating process. The metal layer settles on the bottom of the basin in the processing reactor below the molten glass. Both layers are tapped as necessary, depending on the metal/inorganic content of the waste stream.
The vitrified product can be used in a variety of commercial applications including concrete aggregate, insulation, roadbed construction, and even in decorative tiles. The metal layer can contain relatively pure amounts of iron, copper and aluminum.
It is important to note that the composition of end-products varies with the waste being processed. For example, processing medical waste, with a relatively high percentage of paper and plastic or pharmaceutical manufacturing waste with high levels of carbon-based constituents would produce meaningful levels of syngas, and a lesser amount of glass product. Conversely, processing fly ash from the high temperature boiler in a TVRC would produce lower amounts of syngas and relatively more vitrified product.
Plasma Thermal Destruction & Recovery waste to energy systems are driven by proprietary, state-of-the-art instrumentation and computerized control systems. The Plasma Thermal Destruction & Recovery waste to energy process is a unique, cost-effective and environmentally effective technology that is superior to other mainstream methods of waste treatment:
- The Plasma Thermal Destruction & Recovery waste to energy process can utilize virtually any type of feedstock containing combinations of organic, inorganic and/or heavy-metal constituents thus the pre-processing, staging and management costs are minimized thereby reducing processing costs and enhancing recycling designations.
- Unlike incineration or metal-bearing waste stabilization, the Plasma Thermal Destruction & Recovery waste to energy process is designed to not create any secondary solid wastes that will require further treatment or land filling. As indicated, stand-alone incinerators produce large quantities of bottom and fly ash which are toxic in nature, require further treatment (with stabilization agents) and the resulting post-treated materials (often time whose volume has been doubled) will require final disposal, sometimes in specially designed hazardous waste landfills.
It is also important to note however that through a previous partnership with the Russian Academy of Science, PEAT utilized an AC plasma torch into earlier Plasma Thermal Destruction & Recovery waste to energy systems. The AC plasma torch, which generates the plasma field by utilizing AC electric current directly from the grid without the need for rectifiers (a device, such as a diode, that converts alternating current to direct current). Patents behind the Plasma Thermal Destruction & Recovery waste to energy technology would allow for usage of an AC plasma torch, giving PEAT some additional flexibility. Like electrodes, the AC plasma torch can be more tolerant of a wide range of waste streams (organic and inorganic) and is less expensive to build and to operate than a DC plasma torch. The NCKU facility represented the first applications where an AC plasma torch was utilized in a commercial plant anywhere in the world.