US4036730A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solvent-refining of coal
Assignee: South African Coal Oil and Gas Corp Ltd
•
Filing: 1975-05-20
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Granted: 1977-07-19
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Expires: 1995-05-20
Abstract
Abstract A process is provided for the production of solvent refined coal, which comprises heating the coal while slurried in a solvent under hydrogenation conditions to substantially liquefy the coal followed by a step of separating the non-dissolved solids from the solution, e.g. by filtration, improved by the feature that a small percentage of the liquefiable matter of the coal is combined or recombined chemically with itself and/or existing insoluble matter so as to form larger particles which, e.g. acting as a filtering aid, assist in the separation of the solids from the liquid. These larger particles may be formed by hydrogen starvation during the heating of the slurry to the coal liquefying temperature or by controlled localized overheating prior to the liquefication step or by reducing the hydrogen partial pressure during the liquefication step to a value somewhat below a predetermined value for maximum extraction or by a posttreatment of the liquid product of the liquefication step at a temperature higher than the coal liquefication step. Two or more of these possibilities may be employed in combination.
Inventors
- 👤 Andries Brink
- 👤 Cornelis Kleynjan
- 👤 Quintin John Beukes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:51
CPC Classifications
C; C10; C10L; C10L9/00; C10L9/02; C10L9/04; C10G; C10G1/00; C10G1/04; C10G1/045; C10G1/06; C10G1/065
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
137 words
A process for the production of solvent-refined coal which comprises the steps of: a. heating coal slurried in a solvent having hydrogen carrier characteristics in the presence of hydrogen at a partial pressure of several times atmospheric pressure to substantially liquefy the coal, b. during said heating step controlling the heating temperature and partial pressure of hydrogen to attain a rate of free radical formation, said rate being a function of temperature, which exceeds the rate of radical hydrogenation, said latter rate being a function of partial pressure of hydrogen, and continuing said control for a period of time sufficient to chemically combine a small percentage of the liquefiable matter of the coal with the resulting formation of larger nondissolved solid particles, and c. separating non-dissolved solids from the solution formed by said liquefying and control steps.
Claim 2
Dependent Claim
137 words
A process for the production of solvent-refined coal which comprises the steps of: a. heating coal slurried in a solvent having hydrogen carrier characteristics in the presence of hydrogen at a partial pressure of several times atmospheric pressure to substantially liquefy the coal, b. during said heating step controlling the heating temperature and partial pressure of hydrogen to attain a rate of free radical formation, said rate being a function of temperature, which exceeds the rate of radical hydrogenation, said latter rate being a function of partial pressure of hydrogen, and continuing said control for a period of time sufficient to chemically combine a small percentage of the liquefiable matter of the coal with the resulting formation of larger nondissolved solid particles, and c. separating non-dissolved solids from the solution formed by said liquefying and control steps.
Claim 3
Dependent Claim
28 words
Process as claimed in claim 1 wherein said small percentage is less than 5% by weight of said liquefiable matter which, under optimum extraction conditions would be extractable.
Claim 4
Dependent Claim
28 words
Process as claimed in claim 1 wherein said small percentage is less than 3% by weight of said liquefiable matter which, under optimum extraction conditions would be extractable.
Claim 5
Dependent Claim
14 words
Process as claimed in claim 1 wherein the solids separation takes place by filtration.
Claim 6
Dependent Claim
126 words
Process as claimed in claim 1, wherein the coal, being in the form of a slurry, is heated gradually to the temperature at which the major part of hydrogenative solvent extraction resulting in said liquefying takes place, and this heating is carried out initially with less hydrogen than that required to prevent free radicals of the liquefiable matter from forming said larger particles to a temperature at which radical formation has already commenced in the extractable coal constituents, but is still low, whereafter additional hydrogen is introduced and heating of the coal slurry is continued, now in the presence of sufficient hydrogen for the maintenance of active hydrogenation conditions, to a higher temperature at which the main step of solvent extraction with hydrogenation is carried out.
Claim 7
Dependent Claim
40 words
Process as claimed in claim 5, wherein the slurry is thus heated up at a rate of between 21/2° and 8° C. per minute from about ambient temperature to the temperature at which the main hydrogenation and extraction takes place.
Claim 8
Dependent Claim
24 words
Process as claimed in claim 6 wherein the slurry is thus heated up at a rate of between 4° to 7° C. per minute.
Claim 9
Dependent Claim
22 words
Process as claimed in claim 5 wherein the said hydrogen introduction takes place at a temperature of between 350° and 400° C.
Claim 10
Dependent Claim
19 words
Process as claimed in claim 8 wherein the said hydrogen introduction takes place at between 370° and 395° C.
Claim 11
Dependent Claim
32 words
Process as claimed in claim 5 wherein the main step of extraction with hydrogenation takes place at a temperature at least 10° C. higher than the temperature at which hydrogen is introduced.
Claim 12
Dependent Claim
32 words
Process as claimed in claim 10 wherein the main step of extraction with hydrogenation takes place at a temperature at least 20° C. higher than the temperature at which hydrogen is introduced.
Claim 13
Dependent Claim
22 words
Process as claimed in claim 5 wherein the main step of extraction with hydrogenation takes place at between 400° and 500° C.
Claim 14
Dependent Claim
22 words
Process as claimed in claim 12 wherein the main step of extraction with hydrogenation takes place at between 410° and 450° C.
Claim 15
Dependent Claim
32 words
Process as claimed in claim 1 wherein a controlled particle growth is attained by maintaining controlled localized high temperature zones where the rate of radical formation exceeds the rate of radical hydrogenation.
Claim 16
Dependent Claim
28 words
Process as claimed in claim 14 wherein the effect of localised high temperature zones is assisted by the maintenance of comparatively quiescent conditions in the high temperature region.
Claim 17
Dependent Claim
78 words
Process as claimed in claim 1 which comprises predetermining the value of hydrogen partial pressure during the maintenance of said hydrogenation conditions required for maximum extraction of coal and wherein there is maintained, during said step of heating in a solvent under hydrogenation conditions, a partial pressure of hydrogen which is reduced below the predetermined value of hydrogen partial pressure for maximum extraction of coal by a predetermined value causing a small reduction in the percentage of extraction.
Claim 18
Dependent Claim
30 words
Process as claimed in claim 16 wherein the value of the partial pressure of hydrogen is predetermined experimentally for said small reduction to be up to about 3% by weight.
Claim 19
Dependent Claim
30 words
Process as claimed in claim 17 wherein the value of the partial pressure of hydrogen is predetermined experimentally for said small reduction to be not more than 1% by weight.
Claim 20
Dependent Claim
42 words
Process as claimed in claim 16 wherein the optimum working pressure for full extraction is between 200 and 220 bar and wherein said small reduction in the percentage of extraction is attained by reducing the working pressure to 110 to 150 bar.
Claim 21
Dependent Claim
37 words
Process as claimed in claim 16 combined with the feature that a controlled particle growth is attained by controlled localised maintaining of high temperature zones, where the rate of radical formation exceeds the rate of radical hydrogenation.
Claim 22
Dependent Claim
183 words
A process of the SRC type for the production of socalled "solvent-refined coal" (SRC), which comprises heating coal whilst slurried in a solvent having hydrogen-carrier characteristics and in the presence of hydrogen at a partial pressure of several times atmospheric pressure under hydrogenation conditions to substantially liquefy the coal, followed by a step of separating non-dissolved solids from the solution which is formed as a result of said liquefying and comprising the feature that the liqueform product of said liquefying, prior to the step of separating non-dissolved solids is subjected to a step of postheating at a temperature higher than the temperature during said liquefying, the condition of temperature which determines the rate of free radical formation and the condition of hydrogen partial pressure which determines the rate of radical hydrogenation being controlled during said postheating so that the rate of free radical formation exceeds the rate of radical hydrogenation, so as to chemically combine or recombine constituents of the liquefied matter to result in an increase in particle size in the non-dissolved solids which facilitates the subsequent separation of solids from liquid.
Claim 23
Dependent Claim
183 words
A process of the SRC type for the production of socalled "solvent-refined coal" (SRC), which comprises heating coal whilst slurried in a solvent having hydrogen-carrier characteristics and in the presence of hydrogen at a partial pressure of several times atmospheric pressure under hydrogenation conditions to substantially liquefy the coal, followed by a step of separating non-dissolved solids from the solution which is formed as a result of said liquefying and comprising the feature that the liqueform product of said liquefying, prior to the step of separating non-dissolved solids is subjected to a step of postheating at a temperature higher than the temperature during said liquefying, the condition of temperature which determines the rate of free radical formation and the condition of hydrogen partial pressure which determines the rate of radical hydrogenation being controlled during said postheating so that the rate of free radical formation exceeds the rate of radical hydrogenation, so as to chemically combine or recombine constituents of the liquefied matter to result in an increase in particle size in the non-dissolved solids which facilitates the subsequent separation of solids from liquid.
Claim 24
Dependent Claim
18 words
Process as claimed in claim 21 wherein the postheating is carried out at between 440° and 550° C.
Claim 25
Dependent Claim
18 words
Process as claimed in claim 21 wherein the postheating is carried out at between 450° and 500° C.
Claim 26
Dependent Claim
18 words
Process as claimed in claim 21 wherein the postheating is carried out at between 450° and 480° C.
Claim 27
Dependent Claim
20 words
Process as claimed in claim 21, wherein the effect of the postheating is assisted by maintaining conditions of hydrogen starvation.
Claim 28
Dependent Claim
24 words
Process as claimed in claim 25, wherein hydrogen starvation is attained by letting off pressure resulting in a lowering of the hydrogen partial pressure.
Claim 29
Dependent Claim
16 words
Process as claimed in claim 21 wherein said postheating is carried out in a tube furnace.
Claim 30
Dependent Claim
23 words
Process as claimed in claim 21 wherein said postheating is conducted rapidly, over a short period of time of the order of minutes.
Claim 31
Dependent Claim
202 words
A process of the SRC type for the production of so-called solvent-refined coal (SRC), which comprises heating coal whilst slurried in a solvent having hydrogen-carrier characteristics and in the presence of hydrogen at a partial pressure of several times atmospheric pressure under hydrogenation conditions to substantially liquefy the coal, followed by a step of separating non-dissolved solids from the solution which is formed as a result of said liquefying and comprising the steps of a. determining for a given set of process parameters, selected for effectively liquefying the coal, the relative yields of liquefied matter and non-dissolved solids, b. employing essentially the parameters referred to under (a) above, to manufacture said SRC, subject to the modification that during a stage after the coal has been converted into a slurry and before said step of separating, the application of heat to the slurry is so controlled in relationship to any hydrogen partial pressure at that stage that a small percentage of the relative yield of liquefied matter as determined under (a) is consumed in thermal conversion reactions taking place in lieu of hydrogenation reactions and which cause an increase of particle sizes in the non-dissolved solids, whereby the step of separating is facilitated.
Claim 32
Dependent Claim
202 words
A process of the SRC type for the production of so-called solvent-refined coal (SRC), which comprises heating coal whilst slurried in a solvent having hydrogen-carrier characteristics and in the presence of hydrogen at a partial pressure of several times atmospheric pressure under hydrogenation conditions to substantially liquefy the coal, followed by a step of separating non-dissolved solids from the solution which is formed as a result of said liquefying and comprising the steps of a. determining for a given set of process parameters, selected for effectively liquefying the coal, the relative yields of liquefied matter and non-dissolved solids, b. employing essentially the parameters referred to under (a) above, to manufacture said SRC, subject to the modification that during a stage after the coal has been converted into a slurry and before said step of separating, the application of heat to the slurry is so controlled in relationship to any hydrogen partial pressure at that stage that a small percentage of the relative yield of liquefied matter as determined under (a) is consumed in thermal conversion reactions taking place in lieu of hydrogenation reactions and which cause an increase of particle sizes in the non-dissolved solids, whereby the step of separating is facilitated.
Claim 33
Dependent Claim
24 words
Process as claimed in claim 29, wherein step (b) is controlled for said yield of liquefied matter to be reduced by less than 5%.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |