US 4,924,785 A · Thermal cleaning system

Abstract

A semi-continuous pyrolysis arrangement is disclosed which is particularly useful in the reclamation of a base material in a substantially pure form from a composite material which has organic compounds. The furnace base barrier free zones wherein the waste material is continuously pyrolyzed as it is indexed through the furnace and each zone is controlled in a preset manner established from pyrolyzing a sample waste specimen under controlled conditions. Preferably, the waste is containerized as a particulate solid in discrete static beds permitting a fan exhaust arrangement to establish convective heat transfer with the bed while also establishing the furnace zones. An exothermic zone is provided at the end of the furnace to remove fixed carbon from the pyrolyzed waste by bleeding substoichiometric amounts of air in an oxygen temperature controlled manner to permit recovery of the waste in a substantially pure form.

Claims42

Dependent claims

A thermal reclamation process for recovering a base material from a composite material including said base material and organic compounds, said base material having a critical temperature higher than the volatilizing temperature of said organic compound, said process including the steps of:

(i) heating said composite material by controlling the temperature of the atmosphere in the furnace enclosure to produce an endothermic reaction of said organic material, said endothermic reaction occurring at a temperature less than said critical temperature;
(ii) continuing said endothermic reaction until substantially all the organic material has been volatilized and said composite material is transformed into fixed carbon and said base material;
(iii) providing a substoichiometric concentration of oxygen to said atmosphere to produce an exothermic reaction between said atmosphere and said fixed carbon sufficient to maintain the temperature of said exothermic reaction to be less than said critical temperature, and
(iv) continuing to supply said substoichiometric concentration of oxygen to permit said exothermic reaction to proceed until substantially all of said fixed carbon becomes associated with said atmosphere whereby said base material may be recovered in a substantially pure form.

1 more element

A process for thermally destroying at least the organic compounds of a waste material comprising the steps of:

(a) heating a sample of said waste material in the substantial absence of oxygen at varying temperatures and time periods while recording the weight of the volatiles given off until said organic compounds of said waste material have been substantially volatilized without igniting said sample to define a sample pyrolyzing cycle;
(b) plotting said temperatures recorded in said cycle as a function of time to define a control curve, and dividing said curve over said time into a discrete number of segments with the first segment at the beginning of the cycle and the n.sup.th segment at the end of said volatilization cycle;
(c) providing a furnace having an entrance end and an exit end and n zones therebetween generally equal in number to said n segments;
with the first zone adjacent said entrance end and the n.sup.th zone somewhat adjacent said exit end;
(d) providing conveying means for incrementally moving said composite material through said furnace from said first zone through said n.sup.th zone;
(e) controlling the temperature during the time said waste material stays within each zone in a manner correlated to the time-temperature relationship established by said control curve for each zone whereby complex organic compounds can be substantially volatilized in a controlled manner.

3 more elements

A pyrolysis system for thermally treating a composite material which includes at least one organic compound, said system comprising:

a furnace enclosure substantially free of any physical barriers therein and having an entry end and an exit end;
a plurality of discretely placed, longitudinally spaced exhaust openings in said furnace enclosure between said entry and exit ends, and for each exhaust opening, fan means for directing a stream of atmosphere through a fan outlet situated relative to said exhaust opening, each fan outlet opening with its associated exhaust opening defining a furnace zone so that a plurality of furnace zones extend from said entry to said exit end, said fan means effective to cause said atmosphere to circulate in each zone to establish each zone as a discrete, independently controlled zone;
burner means associated with each zone for controlling, to some degree, the temperature of said atmosphere in each zone;
container drive means for conveying said composite material from said entry end through said furnace zones to said exit end;
microprocessor means for controlling the temperature and said fan means in each zone to insure an endothermic reaction principally by a convective heat transfer reaction in all said furnace zones whereby said organic compound is volatilized at different controlled rates while said composite material is conveyed through said furnace.

2 more elements

Dependencies are inferred from the claim text.

Thermal cleaning system

Life of this patent

Thermal cleaning system

Life of this patent

Abstract

Claims42