US4018481A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gasification of coal in situ
Assignee: In Situ Technology Inc
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Filing: 1976-03-08
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Granted: 1977-04-19
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Expires: 1996-03-08
Abstract
Abstract This invention relates to the production of combustible gases from coal in situ, in which one or more passages are established between the surface of the ground and an underground coal deposit. The coal is set afire and the fire is sustained by injection of an oxidizer for a period of time. Oxidizer injection is terminated, followed by injection of steam for a period of time into the hot coal bed. Produced gases are captured at the surface. Products of combustion from the burn cycle are saved at the surface, reconstituted by the addition of oxygen, then reinjected for subsequent burn cycles until the sulfur dioxide content is sufficiently high to warrant recovery in surface facilities. Condensible gases are cooled in surface facilities with liquids captured apart from noncondensible gases.
Inventors
- 👤 Ruel Carlton Terry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:08
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/24; E21B43/243; E21B43/34; E21B43/40
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
89 words
A method of gasifying coal in situ wherein the underground coal deposit has been preheated to a temperature above the ignition point temperature comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with the fluid injection and removal passages, injecting an oxidizer, gasifying the coal and capturing the gases at the surface; terminating oxidizer injection, then injecting a reducing reactant fluid, gasifying the coal, and capturing the gases at the surface.
Claim 2
Independent Claim
89 words
A method of gasifying coal in situ wherein the underground coal deposit has been preheated to a temperature above the ignition point temperature comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with the fluid injection and removal passages, injecting an oxidizer, gasifying the coal and capturing the gases at the surface; terminating oxidizer injection, then injecting a reducing reactant fluid, gasifying the coal, and capturing the gases at the surface.
Claim 3
Dependent Claim
10 words
The method of claim 1 wherein the oxidizer is air.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein the oxidizer is oxygen enriched air.
Claim 5
Dependent Claim
14 words
The method of claim 1 wherein the oxidizer is flue gas enriched with oxygen.
Claim 6
Dependent Claim
12 words
The method of claim 1 wherein the reducing reactant fluid is steam.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein the reducing reactant fluid is carbon dioxide.
Claim 8
Dependent Claim
36 words
The method of claim 1 further including selective adjustment of the pressure in the fluid passages underground to permit encroachment of water into the reaction zone and to exclude encroachment of water into the reaction zone.
Claim 9
Independent Claim
103 words
A method of gasifying coal in situ wherein the underground coal deposit has been preheated to a temperature above the ignition point temperature comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with the fluid injection and removal passages, injecting an oxidizer, gasifying the coal and the sulfur content of the coal, and capturing the gases at the surface; then reinjecting the captured gases together with an oxidizer, gasifying the coal and the sulfur content of the coal, and capturing the gases at the surface.
Claim 10
Independent Claim
103 words
A method of gasifying coal in situ wherein the underground coal deposit has been preheated to a temperature above the ignition point temperature comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with the fluid injection and removal passages, injecting an oxidizer, gasifying the coal and the sulfur content of the coal, and capturing the gases at the surface; then reinjecting the captured gases together with an oxidizer, gasifying the coal and the sulfur content of the coal, and capturing the gases at the surface.
Claim 11
Independent Claim
154 words
A method of gasifying coal in situ wherein underground processing steps are conducted in concert with aboveground processing steps in order to operate the system at full capacity while delivering a product gas that meets predetermined specifications comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with the fluid injection and fluid removal passages, establishing a first receptacle at the surface, establishing a second receptacle at the surface, establishing a third receptacle at the surface, igniting the coal underground, injecting an oxidizer, gasifying the coal, and capturing the gases in the first receptacle; terminating oxidizer injection, then injecting a reducing reactant fluid, gasifying the coal, and capturing the gases in the second receptacle; passing the gases from the first receptacle to the third receptacle, and passing the gases from the second receptacle to the third receptacle.
Claim 12
Independent Claim
154 words
A method of gasifying coal in situ wherein underground processing steps are conducted in concert with aboveground processing steps in order to operate the system at full capacity while delivering a product gas that meets predetermined specifications comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with the fluid injection and fluid removal passages, establishing a first receptacle at the surface, establishing a second receptacle at the surface, establishing a third receptacle at the surface, igniting the coal underground, injecting an oxidizer, gasifying the coal, and capturing the gases in the first receptacle; terminating oxidizer injection, then injecting a reducing reactant fluid, gasifying the coal, and capturing the gases in the second receptacle; passing the gases from the first receptacle to the third receptacle, and passing the gases from the second receptacle to the third receptacle.
Claim 13
Dependent Claim
44 words
The method of claim 9 further including the steps of adjusting the time period for injection of oxidizer as compared to the time period for injection of the reducing reactant fluid and apportioning the gases passed from the first receptacle to the third receptacle.
Claim 14
Dependent Claim
43 words
The method of claim 9 further including the steps of adjusting the time period for injection of reducing reactant fluid as compared to the time period for injection of oxidizer and apportioning the gases passed from the second receptacle to the third receptacle.
Claim 15
Dependent Claim
19 words
The method of claim 9 further including the step of adjusting the quantity and quality of the injected oxidizer.
Claim 16
Dependent Claim
21 words
The method of claim 9 further including the step of adjusting the quantity and quality of the injected reducing reactant fluid.
Claim 17
Dependent Claim
31 words
The method of claim 9 further including the steps of injecting a first reducing reactant fluid, terminating the injection of the first reactant fluid, then injecting a second reducing reactant fluid.
Claim 18
Dependent Claim
21 words
The method of claim 14 wherein the first reducing reactant fluid is carbon dioxide and the second reactant fluid is steam.
Claim 19
Independent Claim
113 words
A method of gasification of coal in situ wherein the underground coal deposit has been preheated to a temperature above the ignition point temperature comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with fluid injection and fluid removal passages, injecting a reactive fluid, gasifying the coal into condensible and non-condensible gases, establishing a receptacle for the gases at the surface, establishing a heat transfer means within said receptacle, capturing the gases in the said receptacle, lowering the temperature of the gases in the said receptacle, and capturing the condensed liquids apart from the gases.
Claim 20
Independent Claim
113 words
A method of gasification of coal in situ wherein the underground coal deposit has been preheated to a temperature above the ignition point temperature comprising the steps of: establishing fluid injection and fluid removal passages connecting the coal formation to a surface location, establishing a fluid passage through the coal interconnected with fluid injection and fluid removal passages, injecting a reactive fluid, gasifying the coal into condensible and non-condensible gases, establishing a receptacle for the gases at the surface, establishing a heat transfer means within said receptacle, capturing the gases in the said receptacle, lowering the temperature of the gases in the said receptacle, and capturing the condensed liquids apart from the gases.
Claim 21
Dependent Claim
17 words
The method of claim 16 further including the step of expanding the gases inbound to said receptacle.
Claim 22
Dependent Claim
16 words
The method of claim 16 further including the step of adding heat to the captured liquids.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-18 | 1980-10-18 | 1981-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-18 | 1984-10-18 | 1985-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-18 | 1988-10-18 | 1989-04-19 | $7700.00 | Window Closed / Lapsed |