US4492649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carbon dioxide removal method employing packed solid calcium hydroxide
Assignee: Individual
•
Filing: 1982-09-23
•
Granted: 1985-01-08
•
Expires: 2002-09-23
Abstract
Abstract In order to remove carbon dioxide from an off-gas stream and immobilize it in solid stable form, the gas is passed through a packed bed of calcium hydroxide maintained at a temperature in the range 10 DEG C.-50 DEG C., the moisture content of the gas being controlled so as to correspond to a relative humidity from 40% to 100% at the bed temperature.
Inventors
- 👤 Christopher H. Cheh
- 👤 Roger W. Glass
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:17
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/02; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/62; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02C; Y02C20/00; Y02C20/40
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
129 words
A method of removing carbon dioxide from a gas stream by passing the gas stream through a packed bed of calcium hydroxide, wherein the bed is maintained at a temperature in the range 10° C.-50° C., and wherein the moisture content of the gas is controlled to a value corresponding to a relative humidity in the range 40%-100% at the bed temperature and such that the resultant conversion of calcium hydroxide is not less than 0.15, the conversion being defined by ##EQU2## where R is the gas flow rate, C is the carbon dioxide concentration upstream of the bed, T is the time required for the downstream concentration of carbon dioxide to reach 5% of the upstream concentration, and W is the weight of calcium hydroxide in the bed.
Claim 2
Independent Claim
129 words
A method of removing carbon dioxide from a gas stream by passing the gas stream through a packed bed of calcium hydroxide, wherein the bed is maintained at a temperature in the range 10° C.-50° C., and wherein the moisture content of the gas is controlled to a value corresponding to a relative humidity in the range 40%-100% at the bed temperature and such that the resultant conversion of calcium hydroxide is not less than 0.15, the conversion being defined by ##EQU2## where R is the gas flow rate, C is the carbon dioxide concentration upstream of the bed, T is the time required for the downstream concentration of carbon dioxide to reach 5% of the upstream concentration, and W is the weight of calcium hydroxide in the bed.
Claim 3
Dependent Claim
40 words
A method according to claim 1, wherein the bed is maintained at a temperature in the range 20° C.-30° C., the moisture content of the gas stream corresponding to a relative humidity in the range 80%-100% at the bed temperature.
Claim 4
Dependent Claim
42 words
A method according to claim 1 or claim 2, wherein the initial moisture content of the gas stream corresponds to a relative humidity greater than 100% at the bed temperature, said control comprising dehumidifying the gas prior to passage through the bed.
Claim 5
Dependent Claim
49 words
A method according to claim 1 or claim 2, wherein the initial moisture content of the gas stream corresponds to a relative humidity less than the minimum of said relative humidity range at the bed temperature, said control comprising humidifying the gas stream prior to passage through the bed.
Claim 6
Independent Claim
130 words
A method of removing carbon dioxide from a stream of industrial off-gas by passing the gas stream through a packed bed of calcium hydroxide maintained at a temperature in the range 10° C.-50° C., including the step of humidifying the gas stream to raise its moisture content to a value corresponding to a relative humidity in the range 40%-100% at the bed temperature and such that the resultant conversion of calcium hydroxide is not less than 0.15, the conversion being defined by ##EQU3## where R is the gas flow rate, C is the carbon dioxide concentration upstream of the bed, T is the time required for the downstream concentration of carbon dioxide to reach 5% of the upstream concentration, and W is the weight of calcium hydroxide in the bed.
Claim 7
Independent Claim
130 words
A method of removing carbon dioxide from a stream of industrial off-gas by passing the gas stream through a packed bed of calcium hydroxide maintained at a temperature in the range 10° C.-50° C., including the step of humidifying the gas stream to raise its moisture content to a value corresponding to a relative humidity in the range 40%-100% at the bed temperature and such that the resultant conversion of calcium hydroxide is not less than 0.15, the conversion being defined by ##EQU3## where R is the gas flow rate, C is the carbon dioxide concentration upstream of the bed, T is the time required for the downstream concentration of carbon dioxide to reach 5% of the upstream concentration, and W is the weight of calcium hydroxide in the bed.
Claim 8
Dependent Claim
40 words
A method according to claim 5, wherein the bed is maintained at a temperature in the range 20° C.-30° C., the moisture content of the gas stream corresponding to a relative humidity in the range 80%-100% at the bed temperature.
Claim 9
Independent Claim
96 words
A method of removing and immobilizing carbon dioxide from a gas stream including carbon dioxide containing radioactive carbon as a constituent, which comprises providing a gas filter comprising a packed bed of solid Ca(OH) 2 prepared by hydrating CaO and drying, crushing and packing the resultant hydroxide, contacting the gas stream with water to raise its moisture content to a value corresponding to a relative humidity in the range 80%-100% at the temperature of the bed, and flowing the humidified gas stream through the gas filter to effect conversion of the calcium hydroxide to calcium carbonate.
Claim 10
Independent Claim
96 words
A method of removing and immobilizing carbon dioxide from a gas stream including carbon dioxide containing radioactive carbon as a constituent, which comprises providing a gas filter comprising a packed bed of solid Ca(OH) 2 prepared by hydrating CaO and drying, crushing and packing the resultant hydroxide, contacting the gas stream with water to raise its moisture content to a value corresponding to a relative humidity in the range 80%-100% at the temperature of the bed, and flowing the humidified gas stream through the gas filter to effect conversion of the calcium hydroxide to calcium carbonate.
Claim 11
Dependent Claim
19 words
A method according to claim 7, wherein the temperature of the bed is in the range 20° C.-30° C.
Claim 12
Dependent Claim
66 words
A method according to claim 7, wherein the gas filter is formed by a column comprising a plurality of relatively flat, spaced apart beds of crushed solid calcium hydroxide, the column defining a gas flow path and the beds being arranged in series with respect to said flow path, the spacings between the beds modifying the gas flow to effect redistribution thereof between the filter stages.
Claim 13
Dependent Claim
16 words
A method according to claim 9, wherein the temperature of the bed is 20° C.-30° C.
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) | 1988-01-08 | 1988-07-09 | 1989-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-08 | 1992-07-09 | 1993-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-08 | 1996-07-09 | 1997-01-08 | $7700.00 | Window Closed / Lapsed |