US4424108A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for heating coal-oil slurries
Assignee: RUHRKOLE AG
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Filing: 1982-01-08
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Granted: 1984-01-03
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Expires: 2002-01-08
Abstract
Abstract Controlling gas to slurry volume ratio to achieve a gas holdup of about 0.4 when heating a flowing coal-oil slurry and a hydrogen containing gas stream allows operation with virtually any coal to solvent ratio and permits operation with efficient heat transfer and satisfactory pressure drops. The critical minimum gas flow rate for any given coal-oil slurry will depend on numerous factors such as coal concentration, coal particle size distribution, composition of the solvent (including recycle slurries), and type of coal. Further system efficiency can be achieved by operating with multiple heating zones to provide a high heat flux when the apparent viscosity of the gas saturated slurry is highest. Operation with gas flow rates below the critical minimum results in system instability indicated by temperature excursions in the fluid and at the tube wall, by a rapid increase and then decrease in overall pressure drop with decreasing gas flow rate, and by increased temperature differences between the temperature of the bulk fluid and the tube wall. At the temperatures and pressures used in coal liquefaction preheaters the coal-oil slurry and hydrogen containing gas stream behaves essentially as a Newtonian fluid at shear rates in excess of 150 sec.sup. -1. The gas to slurry volume ratio should also be controlled to assure that the flow regime does not shift from homogeneous flow to non-homogeneous flow. Stable operations have been observed with a maximum gas holdup as high as 0.72.
Inventors
- 👤 Walter A. Braunlin
- 👤 Alan Gorski
- 👤 Leo J. Jaehnig
- 👤 Clifford J. Moskal
- 👤 Joseph D. Naylor
- 👤 Krishnia Parimi
- 👤 John V. Ward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:59
CPC Classifications
C; C10; C10G; C10G1/00; C10G1/06; C10G1/065; Y; Y10; Y10S; Y10S208/00; Y10S208/01
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
77 words
A process for heating a coal-oil slurry in a heating zone comprising controllably heating in a flowing stream a coal-oil slurry and a gas containing at least about 70 mol per cent hydrogen while controlling the volume ratio of slurry to gas so as to maintain homogeneous flow in the portion of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 500° F. (260° C.) to about 600° F. (332° C.).
Claim 2
Dependent Claim
77 words
A process for heating a coal-oil slurry in a heating zone comprising controllably heating in a flowing stream a coal-oil slurry and a gas containing at least about 70 mol per cent hydrogen while controlling the volume ratio of slurry to gas so as to maintain homogeneous flow in the portion of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 500° F. (260° C.) to about 600° F. (332° C.).
Claim 3
Dependent Claim
38 words
The process of claim 1 further comprising maintaining homogeneous flow in segments of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 450° F. (232° C.) to about 650° F. (343° C.).
Claim 4
Dependent Claim
15 words
The process of claim 1 further comprising maintaining homogeneous flow throughout the entire heating zone.
Claim 5
Dependent Claim
25 words
A process of claim 1 further comprising maintaining a minimum average heat flux of 6,000 btu/hr-ft 2 (16,200 kcal/hr-m 2 ) throughout the heating zone.
Claim 6
Dependent Claim
25 words
A process of claim 2 further comprising maintaining a minimum average heat flux of 6,000 btu/hr-ft 2 (16,200 kcal/hr-m 2 ) throughout the heating zone.
Claim 7
Dependent Claim
25 words
A process of claim 3 further comprising maintaining a minimum average heat flux of 6,000 btu/hr-ft 2 (16,200 kcal/hr-m 2 ) throughout the heating zone.
Claim 8
Dependent Claim
25 words
The process of claim 1 wherein the coal-oil slurry is made from a coal selected from a group consisting of bituminous, sub-bituminous coals, and lignites.
Claim 9
Dependent Claim
49 words
The process of claim 1 further comprising controlling the flow rates of said slurry and gas and the rate of heating such that the slurry has a residence time in said heating zone of at least 1.5 minutes after the slurry temperature has risen to 450° F. (232° C.).
Claim 10
Dependent Claim
47 words
The process of claim 1 wherein the flowrates of said gas and said slurry are controlled such that the ratio of the average actual volume of gas to the average actual volume of slurry at the inlet of the heating zone is at least 1 to 1.
Claim 11
Dependent Claim
48 words
The process of claim 1 wherein the flow rates of said gas and said slurry are controlled such that the ratio of the average actual volume of gas to the average actual volume of slurry at the inlet of the heating zone is at least 2 to 1.
Claim 12
Dependent Claim
20 words
The process of claim 1 wherein the coal-oil slurry is prepared from a recycle slurry from a coal liquefaction process.
Claim 13
Dependent Claim
46 words
The process of claim 11 wherein the coal-oil slurry is prepared with a swelling coal having particles classified so that at least 80% by weight pass through a 30 mesh (U.S. Series) screen and no more than 30% pass through a 400 mesh (U.S. Series) screen.
Claim 14
Dependent Claim
28 words
The process of claim 1 further comprising controlling the velocity of said slurry so that it flows with a shear rate of at least 150 sec -1 .
Claim 15
Dependent Claim
28 words
The process of claim 13 further comprising controlling the velocity of said slurry so that it flows with a shear rate no greater than 300 sec -1 .
Claim 16
Dependent Claim
113 words
The process of claim 7 further comprising controlling the rate of heating so as to maintain an average heat flux throughout the heating zone ranging from: 8,000 to 12,000 btu/hr-ft 2 (21,600-32,400 kcal/hr-m 2 ) while the coal-oil slurry is heated to about 450° F. (232° C.), from 12,000 to 18,000 btu/hr-ft 2 (32,400-48,600 kcal/hr-m 2 ) while the coal-oil slurry is heated from about 450° F. (232° C.) to about 650° F. (343° C.), 8,000 to 12,000 btu/hr-ft 2 (21,600-32,400 kcal/hr-m 2 ) while coal-oil slurry is heated above 650° F. (343° C.); and to maintain a maximum inside film temperature of the slurry no greater than about 925° F. (425° C.).
Claim 17
Dependent Claim
73 words
A process for heating a coal-oil slurry in a heating zone comprising controllably heating in a flowing stream a coal-oil slurry and a gas containing at least about 70 mol percent hydrogen while maintaining a minimum gas holdup of about 0.4 and homogeneous flow in those segments of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 500° F. (260° C.) to about 600° F. (332° C.).
Claim 18
Dependent Claim
73 words
A process for heating a coal-oil slurry in a heating zone comprising controllably heating in a flowing stream a coal-oil slurry and a gas containing at least about 70 mol percent hydrogen while maintaining a minimum gas holdup of about 0.4 and homogeneous flow in those segments of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 500° F. (260° C.) to about 600° F. (332° C.).
Claim 19
Dependent Claim
39 words
The process of claim 16 further comprising maintaining homogeneous flow in those segments of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 450° F. (232° C.) to about 650° F. (343° C.).
Claim 20
Dependent Claim
15 words
The process of claim 16 further comprising maintaining homogeneous flow throughout the entire heating zone.
Claim 21
Dependent Claim
15 words
A process of claim 16 further comprising maintaining a minimum holdup of at least 0.38.
Claim 22
Dependent Claim
39 words
The process of claim 19 further comprising maintaining homogeneous flow in the segments of the heating zone where the bulk temperature of the coal-oil slurry is heated from about 450° F. (232° C.) to about 650° F. (343° C.).
Claim 23
Dependent Claim
15 words
The process of claim 19 further comprising maintaining homogeneous flow throughout the entire heating zone.
Claim 24
Dependent Claim
15 words
A process of claim 19 further comprising maintaining a gas holdup not greater than 0.6.
Claim 25
Dependent Claim
39 words
The process of claim 22 further comprising maintaining homogeneous flow in the segments of the heating zone where the bulk temperature of the coal-oil slurry is heated from about 450° F. (232° C.) to about 650° F. (343° C.).
Claim 26
Dependent Claim
15 words
The process of claim 22 further comprising maintaining homogeneous flow throughout the entire heating zone.
Claim 27
Dependent Claim
25 words
A process of claim 16 further comprising maintaining a minimum average heat flux of 6,000 btu/hr-ft 2 (16,200 kcal/hr-m 2 ) throughout the heating zone.
Claim 28
Dependent Claim
25 words
A process of claim 17 further comprising maintaining a minimum average heat flux of 6,000 btu/hr-ft 2 (16,200 kcal/hr-m 2 ) throughout the heating zone.
Claim 29
Dependent Claim
25 words
A process of claim 24 further comprising maintaining a minimum average heat flux of 6,000 btu/hr-ft 2 (16,200 kcal/hr-m 2 ) throughout the heating zone.
Claim 30
Dependent Claim
269 words
A coal liquefaction process comprising: preheating in a heating zone a coal-oil slurry and a hydrogen containing gas stream to a temperature ranging from about 700° F. (371° C.) to about 870° F. (466° C.); and reacting said preheated slurry with said gas at temperatures controlled between about 700° F. (371° C.) to about 870° F. (466° F.) and at hydrogen partial pressures ranging between about 1,000 lb/in 2 (690 newton/cm 2 ) and about 4,000 lb/in 2 (2,760 newton/cm 2 ) for hydrogenation and hydrocracking; wherein the coal-oil slurry at the inlet to the heating zone has a temperature between 250° F. (121° C.) and about 500° F. (260° C.), contains at least about 20% by weight swelling coal, and flows with a superficial velocity between 1.5 ft/sec (0.46 m/sec) and about 15 ft/sec (4.6 m/sec); the hydrogen containing gas at the inlet to the heating zone contains at least 70 mol percent hydrogen, and flows with a superficial velocity between about 1 ft/sec (0.3 m/sec) and about 30 ft/sec (9 m/sec) and with hydrogen partial pressures between 1,000 lb/in 2 (690 newton/cm 2 ) and about 4,000 lb/in 2 (2,760 newton/cm 2 ); the ratio of the average actual volume of said gas to the actual average volume of said slurry at the inlet to the heating zone is at least 1.0; and the coal-oil slurry and hydrogen containing gas stream maintains homogeneous flow throughout the heating zone in those segments of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 500° F. (260° C.) to about 600° F. (332° C.).
Claim 31
Dependent Claim
269 words
A coal liquefaction process comprising: preheating in a heating zone a coal-oil slurry and a hydrogen containing gas stream to a temperature ranging from about 700° F. (371° C.) to about 870° F. (466° C.); and reacting said preheated slurry with said gas at temperatures controlled between about 700° F. (371° C.) to about 870° F. (466° F.) and at hydrogen partial pressures ranging between about 1,000 lb/in 2 (690 newton/cm 2 ) and about 4,000 lb/in 2 (2,760 newton/cm 2 ) for hydrogenation and hydrocracking; wherein the coal-oil slurry at the inlet to the heating zone has a temperature between 250° F. (121° C.) and about 500° F. (260° C.), contains at least about 20% by weight swelling coal, and flows with a superficial velocity between 1.5 ft/sec (0.46 m/sec) and about 15 ft/sec (4.6 m/sec); the hydrogen containing gas at the inlet to the heating zone contains at least 70 mol percent hydrogen, and flows with a superficial velocity between about 1 ft/sec (0.3 m/sec) and about 30 ft/sec (9 m/sec) and with hydrogen partial pressures between 1,000 lb/in 2 (690 newton/cm 2 ) and about 4,000 lb/in 2 (2,760 newton/cm 2 ); the ratio of the average actual volume of said gas to the actual average volume of said slurry at the inlet to the heating zone is at least 1.0; and the coal-oil slurry and hydrogen containing gas stream maintains homogeneous flow throughout the heating zone in those segments of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 500° F. (260° C.) to about 600° F. (332° C.).
Claim 32
Dependent Claim
44 words
The process of claim 28 wherein the coal-oil slurry and gas stream maintains homogeneous flow in those segments of the heating zone where the bulk temperature of the coal-oil slurry is raised from about 450° F. (232° C.) to about 650° F. (343° C.).
Claim 33
Dependent Claim
20 words
The process of claim 28 wherein the coal-oil slurry and gas stream maintains homogeneous flow throughout the entire heating zone.
Claim 34
Dependent Claim
38 words
The process of claim 28 wherein the ratio of the average actual volume of said gas to the average actual volume of said slurry at the inlet to the heating zone is at least about 2 to 1.
Claim 35
Dependent Claim
37 words
The process of claim 29 wherein the ratio of the average actual volume of said gas to the average actual volume of said slurry at the inlet to the heating zone is at least 2 to 1.
Claim 36
Dependent Claim
51 words
The process of any of claims 28 to 32 wherein the coal-oil slurry is prepared from a recycle slurry from a coal liquefaction process having a minimum boiling point of about 380° F. (193° C.) and a swelling coal selected from the group consisting of bituminous coals, sub-bituminous coals and lignites.
Claim 37
Dependent Claim
20 words
The process of claim 33 wherein the coal-oil slurry contains between about 25% and about 50% by weight total solids.
Claim 38
Dependent Claim
37 words
The process of claim 34 wherein the coal-oil slurry contains 30% by weight swelling bituminous coal and between 30% and 50% by weight total solids, and the hydrogen containing gas contains at least 90% by weight hydrogen.
Claim 39
Dependent Claim
41 words
The process of claim 35 wherein the coal particles are classified so that at least 80% by weight pass through a 30 mesh (U.S. Series) screen and no more than 30% by weight pass through a 400 mesh (U.S. Series) screen.
Claim 40
Dependent Claim
136 words
The process of any of claims 28 to 32 wherein: the coal-oil slurry is preheated in the heating zone to a temperature between about 750° F. (399° C.) and about 860° F. (460° C.); the coal-oil slurry is reacted in the reaction zone with the hydrogen containing gas at temperatures controlled between about 750° F. (399° C.) and 860° F. (460° C.) and at hydrogen partial pressures between 1,000 (690 newton/cm 2 ) and 2,500 lb/in 2 (1,725 newton/cm 2 ); the coal-oil slurry at the inlet to the heating zone flows with a superficial velocity between about 4 ft/sec (1.2 m/sec) and about 10 ft/sec (3 m/sec); the hydrogen containing gas at the inlet to the heating zone flows with a superficial velocity between about 10 ft/sec (3 m/sec) and about 15 ft/sec (4.6 m/sec).
Claim 41
Dependent Claim
21 words
The process of claim 37 wherein the hydrogen containing gas in the heating zone has the minimum holdup of about 0.4.
Claim 42
Dependent Claim
21 words
The process of claim 37 wherein the hydrogen containing gas in the heating zone has a minimum holdup of about 0.38.
Claim 43
Dependent Claim
95 words
The process of claim 37 further comprising controlling the rate of preheating so as to maintain an average heat flux throughout the heating zone ranging from: 8,000 to 12,000 btu/hr-ft 2 (21,600-32,400 kcal/hr-m 2 ) while the coal-oil slurry is heated to about 450° F. (232° C.); from 12,000 to 18,000 btu/hr-ft 2 (32,400-48,600 kcal/hr-m 2 ) while the coal-oil slurry is heated from about 450° F. (232° C.) to about 650° F. (343° C.), and 8,000 to 12,000 btu/hr-ft 2 (21,600-32,400 kcal/hr-m 2 ) while coal-oil slurry is heated above 650° F. (343° C.).
Claim 44
Dependent Claim
59 words
The process of any of claims 28, 30, 32 or 36 further comprising controlling the flowrate of the coal-oil slurry and hydrogen containing gas stream in the heating zone and controlling the rate of preheating so that the coal-oil slurry remains in the heating zone at least 1.5 minutes after it has been preheated to 450° F. (232° 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) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |