Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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813-012-0
83/
TITLE: PROCESS OF HYDROGENATION OF COAL, HEAVY OIL,
BITUMEN AND THE LIKE
~rhis invention relates to the liquid-phase or
combined liquid- and gas-phase hydrogenation o~ coal,
heavy oil, bitumen and similar materials such as the
residues from the pot distillation or vacuum distillation
of crude oil. More particularly, the invention relates
to the separation and recovery of liquid products ~rom
the residues remaining after primary separation of
products immediately after the hydrogenation step in such
processes.
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It is known, for example from ~. Kronig, " m e
: Catalytic Pressure Hydrogenation of Coal, Tars and
Mineral Oils", Berlin~Gottingen/Heidelberg (1950), that
coal, heavy oils and bitumen as well as other re~idual
carbonaceous materials can be converted into low boiling
hydrocarbon mixtures by a process wherein they are mixed
with hydrogen and a catalyst, and optionally also with a
filurrying oil derived ~rom the product, and this mixture
is heated under a pressure of 500-700 bar, pre~erably
100-325 bar, in a heater to a temperature of 200-500C,
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preferably 350-450C. AEter passing through a preheater
the mixture is fed from below through a reactor system in
which the hydrocracking reaction takes place at
temperatures between 250 and 550C, preferably 38~-400C,
which produces cleaving of larger molecules as well as
partial desulfurization, denitrification and
deoxygenation.
The preferred catalysts are single-pass catalysts.
In the hydroyenation of coal these are for example
molybdic acid, tin oxalate/ammonium chloride, sayer-
process aluminas and red mud. For the hydrogenation of
heavy oil and bitumen, catalysts are used which contain
catalytically active metal compounds, for example, of
tungsten, molybdenum, lead, tin, chromium, cobalt and
nickel, and especially of iron, on a carrier such as
activated carbon or especially coke. The catalysts are
used in proportions up to 10 %, by weight, preferably 1
to 6 %~ by weight, calculated on the startin~ material.
Especially ef~ec~ive catalysts are iron compounds which
are converted into iron sulfide under the reaction
conditions, e.g., iron sulfate, in amounts of 2 to 7 ~ by
weight on activated carbon or coke.
From the top of the reactor the reaction mixture is
taken to a hot separator, from the top of which gaseous
and vapor-phase reaction products are withdrawn. From
the bottom of the separator the unreacted starting
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material, asphaltenes, and catalyst, as well as a certain
heavy and middle oil fraction are witlldrawn as a hot
sludge. The hot separator, which may also comprise a
system of several separators connected in series, i~
operated at temperatures up to 100 K, preferably 20 to 40
K, below the reactor temperature.
me gaseous and vapor-phase products withdrawn from
the top of the hot separator are either taken to a cold
depressurization system and then to further operations,
or are immediately fed under the prevailing reaction
pressure into the top of a system of reactors in which
the gaseous or vapor-phase products are further
desulfurized, denitrified, deoxygenated as well as
cleaved on a fixed-bed catalyst (cf. W. Urban, "Petroleum
Processing in the Scholvener 300 Atmosphere Combination
Hydrogenation Reactor", Erdol und Kohle, 8 ~1955), pages
780-782). me products of this "combination
hydrogenation" are also taken to a co:Ld separator system
and thence to further processing.
It is known to subject the material withdrawn from
the bottom of the hot separator to a vacuum distillation
or a destructive distillation to increase the yield of
liquid product. It can also be recycled in part to the
liquid phase reactor. This recycling has the
disadvantage that the asphaltene level in the reactor
increases, which increases the coking tendency of the
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reaction material. Distillation and destructive
distillation are difficult to control because of the
particular type of sludges produced in this process, and,
for the most part only a limited yield of liquid products
is possible even from the principal method, destructive
distillation.
Therefore, a need has continued to exist for a
process for recovering liquid products from the residues
from hydrogenation oE coal, heavy oil and the like, which
does not sufer from the drawbacks of the known
processes.
Accordingly, it is an object of the disclosure to
provide a method or recovering liquid products from the
residues from hydrogenation of coal, heavy oil, bitumen,
and the like.
A further object is to increase the yield of useful
products from hydrogenation of coal, heavy oil, and the
like.
A further object is to use process gases in a method
of recovering additional liquid products in the
hydrogenation of coal, heavy oil, and the like.
Further ohjects will be apparent
from the description which ~olLows.
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The objects have been achieved by a
process for hydrogena~ion of carbonaceous materials such
as coal, heavy oil, bitumen, and the like comprising a~
contacting said carbonaceous materials with hydrogen and
a hydrogenation catalyst at a temperature oE 250C to
550C and a pressure of 50 to 700 bar, whereby gaseous
products, liquid products and a solid sludge are formed,
b) separating said sludge from said prod~cts at a
temperature up to 100 K lower than the hydrogenation
temperature of step a), c) stripping the sludge of any
liquid products contained therein by contacting it with a
process gas comprising at least a portion of the gaseous
products at a temperature of 20C to 300C and a pressure
of 10 to 300 bar, whereby a process gas stream containing
said liquid product is formed, and d) separating said
liquid products from said process gas stream.
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: Accordiny to the disclosure, the yield of liquid
product of the liquid~phase or combined liquid-phase and
gas-phase hydrogenation is increased by stripping a
portion of the liquid constituents from the bottom
product o~ the hot separator with the help of process
gases. For this purpose the process gas is passed
through the product at temperatures between 20 and 300C,
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preferably 50 to 200C and a pressure between lO and 300
bar, preferably 50 to 200 bar. Any gas prod~ced in the
process can be used as the stripping gas. Preferably an
enriched fraction, obtained by scrubbing the process gas,
which contains methane, ethane, propane, butanes and
pentanes, especially a gas containing a high proportion
of propane, butane and/or pentane, is used.
The treatment of the hot sludge with the process
gases is conveniently carried out continuously by feeding
a pressure vessel connected to the hot separakor system
from the top with the hot sludge and from below with the
process gases. The weight ratio hot sludge : process
gases is l : 10 r pre~erably l : 3; the throughput is 0.2
to 2,0 m3r preferably 0.3 to 0.6 m3 of sludge per m3 of
the pressure vessel volume.
The stripping gas can be freed from the components
removed from the hydrogenation residue by decreasing the
pressure from lO0 to l bar, pre~erably 70 to 30 bar or by -
increasing the temperature by 20 to 150 K, preferably 50
to 100 K, or a combination of both procedures, for
example, an increa~se in temperature of 20 to 70 K with a
decrease in the pressure from 100 to 50 bar. The liquid
products are refined or cracked after reheating in the
gas phase reactor; in the case of coal hydrogenation they
; can be used as a slurrying oil free of asphaltenes. lhe
strippiny gas can be used again for the separation after
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increasing the pressure by means of a compressor or a
blower or after cooling.
The residue from the treatment of the hot sludge
with the process gases, which contains solid materials
and is enriched in rnetals and asphaltenes, is removed
from the process via a purging system under gas pressure
and can be taken to a gasification process in order to
supply'the hydrogen requirernents of the hydrogenation
process.
Having generally described the inventive subject matter,
a more complete understanding can be obtained by reference to
certain specific examples, which are provided herein for
purposes of illustration only and are not intended to be
limiting unless otherwise 'specified.
'Example
In a vertically oriented tubular reactor of 4.5 1
capacity, 4.0 kg/h of a residue'from the vacuum
distillation of Arabian light crude oil was hydrogenated
with 3 Nm3/h of hydrogen at 450C and 280 bar. To the
vacuum residue was added 5 % by weight oE a finely
divided coke, on which 50 g FeSO4/kg ~f coke were
supported. From the hydrogenation product leavlng the
top of the reactor 1.6 kg/h of hot sludge were removed in
a hot separator operated at 420C.
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~ is hot sludge was treated in a downstream vessel
of 5 1 capacity, provided with integral means for
separation of gas and liquid, with 4.8 kg/h of a propane-
butane mixture ~propane : butane weight ratio 3 : 2) at
200 bar and 150C. The gaseous product was depre.ssurized
to 40 bar, whereby 0.9 kg/h of a liquid product with a
boiling point end of 520C separated. me product was
free of asphaltenes and metals, its H/C ratio was 1.3;
the sulfur content was about 1.5 ~ by weight.
The æolids in the residue were increased to 28 %, by
weight. The residue contained all metals which were
introduced with the oil as well as the single-pass
catalyst used ln the process.
Having now ully described the invention, it will be
apparent to one of ordinary skill in the art that many
changes and modifications can be made therto without
departing from the spirit or scope of the invention as
set forth herein.
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