US 5,958,264 A · Plasma gasification and vitrification of ashes

Abstract

This invention discloses a method and an apparatus for gasification and vitrification of ashes, such as produced in a hog-fuel fired boiler, by means of a plasma arc. The ashes are introduced into a shaft furnace where two or three tiltable electrodes are located. The plasma arc is ignited between these electrodes which are then tilted from a horizontal to an essentially vertical position whereby the arc is lengthened and then broken into separate arcs, one between each electrode and the slag accumulated at the bottom of the furnace. This plasma arc helps to burn off the organics in the ashes, producing combustion gases that can be used as a source of energy for the boiler, and to keep the slag in molten state, which allows its periodic removal through a tap hole.

Claims18

Dependent claims

Method for gasification and vitrification of ashes by means of a plasma arc which comprises:

(a) feeding a predetermined quantity of ashes into a shaft furnace provided in its heating section with two or three tiltable plasma arc electrodes;
(b) igniting the arc between the ends of the electrodes when they are positioned essentially horizontally, facing one another;
(c) tilting the electrodes downwardly, thereby increasing distance between their ends and lengthening the plasma arc which helps to heat the ashes, producing combustion gases and slag;
(d) allowing the tilting to proceed until the electrodes are positioned essentially vertically and whereby the arc between them is broken while separate arcs are formed, one between each electrode and the slag accumulated at the bottom of the furnace, thereby heating said slag and maintaining it in a molten state;
and
(e) tapping the molten slag when required.

3 more elements

Dependencies are inferred from the claim text.

Plasma gasification and vitrification of ashes

Life of this patent

Plasma gasification and vitrification of ashes

Life of this patent

Abstract

Claims18