Mineral oils: processes and products – Products and compositions – Lubricating oils
Patent
1982-07-13
1985-01-08
Gantz, Delbert E.
Mineral oils: processes and products
Products and compositions
Lubricating oils
C10G 106
Patent
active
044926235
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for hydrogenation of coal in which coal is mixed to a paste with grinding oil. This paste is then pumped to reaction pressure, heated to the temperature of initiation of hydrogenation and then subjected to catalytically accelerated hydrogenation in the presence of hydrogen in a reaction zone.
A prior art process for hydrogenation of coal is one in which the coal to be processed is dried and finely ground, mixed with grinding oil and the resultant coal paste pumped to reaction pressure. The paste is then initially heated in regenerators in heat exchange relationship with the gaseous and vaporous hydrogenation products and then heated in a pre-heater by adding external heat to attain the temperature of initiation of hdrogenation, and finally hydrogenated in a reaction zone in the presence of hydrogen and a suitable catalyst. The product fraction, leaving the reaction zone, is split or divided in a subsequent hot-separator into a vaporous top fraction consisting of gases, gasolines and distilled oils, as well as into a liquid bottom fraction of non-processed coal, ashes, catalytic particles, other high-molecular substances which are difficult to hydrogenate, such as asphalts, as well as bitumen and heavy oil.
While the top fraction is cooled down by heat exchange with the coal paste and withdrawn from the unit, the heavy oil is divided from the bottom fraction and used as grinding oil for the fresh coal.
One of the disadvantages of this prior art process, among others, is having to heat-up the fresh coal paste with regenerators and pre-heaters.
Because of the viscosity of the coal paste, a uniform utilization of the heat exchanger surfaces in the regenerators is only achieved with difficulty. Especially, the further heating of the coal paste is achieved with difficulty because the coal suspended in the coal paste swells a great deal due to the pre-existing high temperatures thereof. This leads to a further increase in viscosity so that ultimately only a pulsating charge of the coal paste can be fed through the pre-heater, resulting in associated high material abrasion. There can be pressure surges up to 10 bar. It is also possible that coking can occur in the individual heat exchangers at the high temperatures therein.
The object of this invention is to develop a process of the kind mentioned in the beginning of this application, which facilitates the heating of the fresh coal paste substantially to the temperature of initiation of hydrogenation.
In a process of the above mentioned kind, this object is achieved, according to the invention, by dividing the coal paste, which was pumped to pressure, into first and second stream portions and feeding them into the reaction zone, wherein th first stream portion is heated outside of the reaction zone by heat exchange with gaseous and vaporous hydrogenation products, and the second stream portion is heated to the temperature of initiation of hydrogenation, within the reaction zone, by transferring the exothermic surplus-heat produced in the reaction zone.
According to the process as per the invention, the heat of the hot gaseous and vaporous hydrogenation products which are either withdrawn directly at the top of the reaction zone or at the top of a hot separator, immediately subsequent to the reaction zone, is transferred only onto a first stream portion of this paste, not to the overall amount of fresh coal paste as in the state of the art. The first stream portion is thereby dimensioned in such a way that the heat contents of the hydrogenation-vapors, occurring at approximately 470.degree. C., suffice to heat it up to the temperature of initiation of hydrogenation of approximately 420.degree. C. This first stream portion comprises as a rule approximately 50 to 70 percent by weight of the resultant fresh coal paste.
Then the heated stream portion is mixed with the pre-heated hydrogenation-hydrogen and fed into the lower range of the reaction zone.
During coal hydrogenation, a large pert of the exothermic heat of reaction is set fr
REFERENCES:
patent: 1923576 (1933-08-01), Krauch et al.
patent: 2639982 (1953-05-01), Kalbach
patent: 4189375 (1980-02-01), Kirby et al.
patent: 4364817 (1982-12-01), Anderson et al.
patent: 4421632 (1983-12-01), Wurfel
Gantz Delbert E.
GfK Gesellschaft fur Kohleverflussigung mbH
Johnson Lance
Ljungman Nils H.
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