Fuel and related compositions – Liquid fuels – Aluminum or heavy metal – other than lead – containing
Patent
1984-07-05
1985-01-22
McCarthy, Helen M.
Fuel and related compositions
Liquid fuels
Aluminum or heavy metal, other than lead, containing
C10L 118
Patent
active
044949600
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a process for the production of pumpable coal slurries which are provided for use in a high-pressure hydrogenation operation, with a content of finely divided coal in high-boiling oils which originate in particular from high-pressure hydrogenation.
CHARACTERISTICS OF THE KNOWN TECHNICAL SOLUTIONS
It is known for the hydrogenation of coal to be carried out using slurries of coal in high-boiling oil fractions which originate from the hydrogenation of coal. In order to produce such slurries, finely divided coal is mixed with the oil for example at a temperature of from 100.degree. to 150.degree. C. In this connection, care should be taken to ensure that the amount of coal which is formed into a slurry in the oils is only such that the resulting mixture remains pumpable so that it can be raised to the hydrogenation pressure which is generally higher than about 150 bars. In addition, it should be noted that, when the slurry is heated to the hydrogenation temperature which is generally higher than about 400.degree. C., the viscosity of the slurry rises rapidly due to swelling of the particles of coal so that it can exceed the limit of the range within which the slurry is still pumpable. In order to prevent that from happening and also in order to reduce the danger of coking when it is heated, the proportion of coal in the slurry must generally be limited to about 45% by weight, depending on the quality of the coal used. Attempts have been made to produce higher levels of concentration of coal, while still being pumpable, by heating the flow of coal and the oil separately to temperatures of from about 350.degree. to 400.degree. C., and only then mixing them (German patent specification No. 1 018 406).
That process is very expensive because of the long mixing times of from 2 to 14 hours and also for reasons relating to the equipment required for carrying the process into effect. In addition, depending on the kind of coal used, in particular when using brown coal or lignite, there is the danger that ageing of the coal molecule may occur in that procedure whereby the number of sites at which the hydrogen attack can preferentially occur is reduced.
OBJECT OF THE INVENTION
The invention is based on the problem of avoiding the above-depicted difficulties in order easily to be able to produce slurries with high goal contents, without coking occurring or without exceeding the limit of the range within which the slurries are pumpable, when heated to hydrogenation temperature.
STATEMENT OF THE ESSENCE OF THE INVENTION
To solve this problem, the invention proposes that such an amount of finely divided coal is mixed into an oil which boils at a temperature of higher than about 200.degree. C., as not to exceed the limit of pumpability in respect of the slurry produced, the slurry is treated for a period of from about 0.5 to 15 minutes at a temperature of from 280.degree. to 450.degree. C., possibly under elevated pressure, and such a further amount of finely divided coal is mixed into the slurry after the above-indicated treatment, that once again the limit of pumpability is not exceeded.
If necessary, the coal used, preferably brown coal or lignite, is pre-dried in the usual manner, and finely ground. The oil used for producing the coal slurry is advantageously oil fractions which are produced in the liquefaction of coal, such as middle and heavy distillates or distillation residues. The mixing operation is desirably effected at elevated temperatures, from about 50.degree. to 250.degree. C. Depending on the kind of coal used and the oil used for producing the mixture, the mixtures produced generally have a coal content of from about 30 to 35% by weight and in particularly cases up to about 45% by weight, as the pumpability of the mixtures is no longer sufficient at higher levels of concentration.
According to the invention, the mixtures are maintained at a temperature of from about 280.degree. to 450.degree. C., advantageously from 350.degree. to 400.degree. C., for
REFERENCES:
patent: 2131308 (1938-09-01), Blumner
patent: 2590733 (1952-03-01), Stillman
patent: 4248691 (1981-03-01), Eisenlohr
Dolkemeyer Wilfried
Keim Karl-Heinz
Meisenburg Ewald
McCarthy Helen M.
Medley Margaret B.
Rheinische Braunkohlenwerke AG
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