Process and apparatus for treatment of excavated landfill material in a plasma fired cupola
AssigneeWestinghouse Electric Corp.
InventorsShyam V. Dighe, Raymond F. Taylor, Jr., Robert J. Steffen, David M. Rohaus
Life of this patent
Estimating the term…
Abstract
Excavatged landfill material is treated in a plasma fired cupola in a process wherein hazardous material such as PCB's are volatilized and consumed in an afterburner above the cupola and hazardous materials containing heavy metals are fixed in vitreous material made molten within the cupola and resulting in a non-leachable solid product.
Claims28
A process for treatment of excavated landfill material contaminated with toxic and hazardous substances comprising:
- providing a plasma-fired cupola having a vertical shaft cupola with an upwardly located charge door and a plasma torch located proximate the bottom of said cupola;
- heating air to a high temperature by said plasma torch and supplying the heated air into said cupola;
- forming a bed of carbonaceous fuel in said cupola heated to combustion by the heated air;
- supplying excavated landfill material and reactive agents through said charge door of said cupola, said reactive agents comprising additional carbonaceous fuel;
- melting the excavated landfill material in the cupola to form a vitreous slag;
- tapping the cupola to take out vitreous slag;
- drawing off-gases from said cupola to an afterburner for destruction of any volatile toxic and hazardous materials contained in the off-gas;
- allowing vitreous slag from the cupola to cool and produce non-hazardous solid material.
A process for treating excavated landfill material in a plasma-fired cupola for safe disposition of toxic or hazardous chemicals such as PCB's and heavy metals, comprising:
- providing a hot bed of carbon fuel in a cupola to a level above and proximate a tuyere from which plasma heated air enters the cupola to form a melt zone near the top of the hot bed at a temperature of from about 3000.degree. F. to about 4500.degree. F. and evolving carbon monoxide;
- feeding a charge of excavated landfill material, fluxing agent and additional carbon fuel onto the hot bed to evolve material that vaporizes at the melt zone temperature including any PCB's therein, to reduce compounds of one or more metals of the group of iron, copper, zinc and lead and without reducing compounds of any metals of the group of chromium and nickel, and to produce molten metal and vitreous slag.
A plasma-fired cupola system arranged for treatment of excavated landfill material comprising:
- a vertical shaft;
- a tuyere proximate the bottom of said shaft;
- at least one plasma torch and a shroud nozzle arranged colinearly with said tuyere;
- air feed lines into said plasma torch and said shroud nozzle respectively;
- means to energize said plasma torch and produce a plasma of the air supplied therein which then heats air supplied in said nozzle;
- a bed of carbon fuel comprising at least about 25% coke in said shaft extending from the bottom thereof to a level proximate to and above said tuyere;
- a charge door located in the upward part of said shaft;
- said shaft containing a charge material on said bed of carbon fuel, said charge material comprising excavated landfill material, additional carbon fuel, and a fluxing agent;
- said shaft having an afterburner chamber in its uppermost region with a stack igniter therein, said charge material on said bed of carbon fuel producing off-gases burned in said afterburner;
- said shaft having a spout in its lowermost region for yielding molten slag and metal produced from said charge material.
Dependencies are inferred from the claim text.