Patent US5024556A successfully refreshed from Google Patents.
US5024556A
Expired / Lapsed
US
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System for enhanced destruction of hazardous wastes by in situ vitrification of soil
Assignee: Battelle Memorial Institute Inc
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Filing: 1989-12-05
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Granted: 1991-06-18
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Expires: 2009-12-05
Abstract
Abstract The present invention comprises a system for promoting the destruction of volatile and/or hazardous contaminants present in waste materials during in situ vitrification processes. In accordance with the present invention, a cold cap (46) comprising a cohesive layer of resolidified material is formed over the mass of liquefied soil and waste (40) present between and adjacent to the electrodes (10, 12, 14, 16) during the vitrification process. This layer acts as a barrier to the upward migration of any volatile type materials thereby increasing their residence time in proximity to the heated material. The degree of destruction of volatile and/or hazardous contaminants by pyrolysis is thereby improved during the course of the vitrification procedure.
Inventors
- 👤 Craig L. Timmerman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:53
CPC Classifications
E; E02; E02D; E02D3/00; E02D3/11; B; B09; B09C; B09C1/00; B09C1/06; B09C1/067; E21; E21B; E21B36/00; E21B36/04; E21B43/00; E21B43/16; E21B43/24; E21B43/2401; H; H05; H05B; H05B3/00; H05B3/0004; H05B3/02; H05B3/03
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
185 words
A method for in situ vitrification of soil (28) containing organic waste material, comprising the steps of: inserting two or more electrodes (10, 12, 14, 16), having surface compositions adapted for adherence with liquefied soil materials, into the soil at spaced apart locations so as to span at least a portion of said waste material; passing an electrical current through said soil and waste material along an electrically conductive resistance path (38) between said electrodes by applying a voltage across said electrodes in order to heat and liquefy said soil and waste material between and adjacent said electrodes; pyrolyzing volatile contaminants within said waste material by increasing their residence time within the heated area between and adjacent said electrodes by forming and maintaining a cold cap structure (46) of resolidified soil and waste material (50) over said liquefied soil and waste material (40) during continued passage of current between said electrodes; and terminating the application of voltage to the electrodes in order to discontinue the flow of said current and permit cooling and solidification of the melted soil and waste material into a densified mass.
Claim 2
Independent Claim
185 words
A method for in situ vitrification of soil (28) containing organic waste material, comprising the steps of: inserting two or more electrodes (10, 12, 14, 16), having surface compositions adapted for adherence with liquefied soil materials, into the soil at spaced apart locations so as to span at least a portion of said waste material; passing an electrical current through said soil and waste material along an electrically conductive resistance path (38) between said electrodes by applying a voltage across said electrodes in order to heat and liquefy said soil and waste material between and adjacent said electrodes; pyrolyzing volatile contaminants within said waste material by increasing their residence time within the heated area between and adjacent said electrodes by forming and maintaining a cold cap structure (46) of resolidified soil and waste material (50) over said liquefied soil and waste material (40) during continued passage of current between said electrodes; and terminating the application of voltage to the electrodes in order to discontinue the flow of said current and permit cooling and solidification of the melted soil and waste material into a densified mass.
Claim 3
Dependent Claim
58 words
The process of claim 1 further including: initially passing a current along said electrically conductive path between said electrodes (10, 12, 14, 16) through said soil and waste material at a comparatively low first power level in order to preferentially promote the formation of said cold cap during first stages of the process of liquification of said soil.
Claim 4
Dependent Claim
24 words
The process of claim 1 wherein said electrodes (10, 12, 14, 16) comprise molybdenum shafts having diameters in the range of approximately 1-3 inches.
Claim 5
Dependent Claim
30 words
The process of claim 3 wherein said molybdenum shafts have an oxidation-resistant coating (54) above the level at which they are to be contacted by the surface of the soil.
Claim 6
Dependent Claim
167 words
In a process for in situ vitrification of soil (28) containing waste materials including the steps of inserting electrodes (10, 12, 14, 16) into said soil and waste material and passing an electrical current through said soil and waste material in order to form a melt of said soil and waste material, the improvement comprising the step of: enhancing the pyrolysis and fixation of volatile material within said waste materials by: a) employing electrodes (10, 12, 14, 16) having exterior compositions at the surface of the melt adapted for adherence with liquefied soil materials at or near the original soil surface, and b) forming a cold cap (46) of resolidified matter over said soil and waste material by controlling the passage of said current at a level promoting formation of a cohesive layer of solid material (50) bridged between said electrodes as opposed to melting said layer, in order to increase the residence time of said volatile material within the heated area between and adjacent said electrodes.
Claim 7
Dependent Claim
167 words
In a process for in situ vitrification of soil (28) containing waste materials including the steps of inserting electrodes (10, 12, 14, 16) into said soil and waste material and passing an electrical current through said soil and waste material in order to form a melt of said soil and waste material, the improvement comprising the step of: enhancing the pyrolysis and fixation of volatile material within said waste materials by: a) employing electrodes (10, 12, 14, 16) having exterior compositions at the surface of the melt adapted for adherence with liquefied soil materials at or near the original soil surface, and b) forming a cold cap (46) of resolidified matter over said soil and waste material by controlling the passage of said current at a level promoting formation of a cohesive layer of solid material (50) bridged between said electrodes as opposed to melting said layer, in order to increase the residence time of said volatile material within the heated area between and adjacent said electrodes.
Claim 8
Dependent Claim
24 words
The process of claim 5 wherein said electrodes (10, 12, 14, 16) comprise molybdenum shafts having diameters in the range of approximately 1-3 inches.
Claim 9
Independent Claim
226 words
A method for in situ vitrification of soil (28) containing organic waste material deposited therein, comprising the steps of: inserting two or more electrodes (10, 12, 14, 16) having surface compositions adapted for adherence with liquefied soil materials into the soil at spaced apart locations so as to span at least a portion of said waste material; forming a cold cap (46) of resolidified material (50) over said soil and waste material by initially passing a current along an electrically conductive path (38) between said electrodes through said soil and waste material at a power level low enough to promote the formation of resolidified matter between and around said electrodes; passing an electrical current through said soil and waste material along said electrically conductive resistance path between said electrodes at a higher power level in order to heat and liquefy said soil and waste material between and adjacent said electrodes while maintaining said cold cap of resolidified soil and waste material over said liquefied soil and waste material, said cold cap functioning to promote the pyrolysis and fixation of any volatile materials within said waste material by enhancing their residence time within the heated area between and adjacent to said electrodes; and terminating the application of current to the electrodes to permit cooling and solidification of the melted soil and waste material into a densified mass.
Claim 10
Independent Claim
226 words
A method for in situ vitrification of soil (28) containing organic waste material deposited therein, comprising the steps of: inserting two or more electrodes (10, 12, 14, 16) having surface compositions adapted for adherence with liquefied soil materials into the soil at spaced apart locations so as to span at least a portion of said waste material; forming a cold cap (46) of resolidified material (50) over said soil and waste material by initially passing a current along an electrically conductive path (38) between said electrodes through said soil and waste material at a power level low enough to promote the formation of resolidified matter between and around said electrodes; passing an electrical current through said soil and waste material along said electrically conductive resistance path between said electrodes at a higher power level in order to heat and liquefy said soil and waste material between and adjacent said electrodes while maintaining said cold cap of resolidified soil and waste material over said liquefied soil and waste material, said cold cap functioning to promote the pyrolysis and fixation of any volatile materials within said waste material by enhancing their residence time within the heated area between and adjacent to said electrodes; and terminating the application of current to the electrodes to permit cooling and solidification of the melted soil and waste material into a densified mass.
Claim 11
Dependent Claim
24 words
The process of claim 7 wherein said electrodes (10, 12, 14, 16) comprise molybdenum shafts having diameters in the range of approximately 1-3 inches.
Claim 12
Dependent Claim
135 words
A structure for use in a process for the in situ vitrification of soil (28) including organic waste material comprising the steps of inserting electrodes (10, 12, 14, 16) into said soil and passing an electrical current through said soil and waste material in order to liquefy the same, said structure including: a) a mass of liquefied and partially liquefied soil and waste material (40) resident between and around said electrodes; and b) a cold cap (46) of solid matter covering said mass of liquefied and partially liquefied soil and waste material, said cold cap comprising a cohesive layer of resolidified soil and waste material which is operative for increasing the residence time of any volatile components of said waste material within the structure as electrical current is passed through the soil and waste material.
Claim 13
Dependent Claim
135 words
A structure for use in a process for the in situ vitrification of soil (28) including organic waste material comprising the steps of inserting electrodes (10, 12, 14, 16) into said soil and passing an electrical current through said soil and waste material in order to liquefy the same, said structure including: a) a mass of liquefied and partially liquefied soil and waste material (40) resident between and around said electrodes; and b) a cold cap (46) of solid matter covering said mass of liquefied and partially liquefied soil and waste material, said cold cap comprising a cohesive layer of resolidified soil and waste material which is operative for increasing the residence time of any volatile components of said waste material within the structure as electrical current is passed through the soil and waste material.
Claim 14
Dependent Claim
49 words
The structure of claim 9 further including c) a chamber (44) located between said mass of liquefied and partially liquefied material and said cold cap, said chamber comprising a vacuous zone in which off-gasses and other volatile components from said soil and waste material can reside for enhanced destruction.
Claim 15
Dependent Claim
24 words
The structure of claim 8 wherein said electrodes (10, 12, 14, 16) comprise molybdenum shafts having diameters in the range of approximately 1-3 inches.
Claim 16
Dependent Claim
30 words
The structure of claim 11 wherein said molybdenum shafts have a oxidation-resistant coating (54) above the level at which they are to be contacted by the surface of the soil.
References Cited (Backward Citations)
FR1320921A
Cited
SU914716A1
Cited
US4376598A
Cited
US4376598B1
Cited
SU1143803A1
Cited
US4957393A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-17 | 1994-12-17 | 1995-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-17 | 1998-12-17 | 1999-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-17 | 2002-12-17 | 2003-06-18 | $7700.00 | Window Closed / Lapsed |