Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~8~5~
PRDCES5 FOR T~E PRODUCTION OF DEASPHALl~D OILS
AND HYDR0CARBOM OIL DISTILLATES
The invention relates to a process for the production of
deasphalted oils and hydrw arbon oil distillates from asphaltenes-
containing hydrocarbon mixtures.
The atmospheric distillation of crude mineral oil for the
production of light hydrocarbon oil distillates, such as gasoline,
kerosine and gas oil yields an asphaltenes-contaim ng residue as a
by-product. Originally these residues (which usually in addition
to asphaltenes also contain a considerable percentage of sulphur
and metals) were used as fuel oil. In view of the growing demand
of light hydrocarbon oil distillates and the shrinking reserves of
crude mineral oil, several treatments aiming at the production of
light hydrocarbon oil distillates from atm~spheric residues have
already been proposed. For instance, a deasphalted oil may be
separated fm m an atmospheric residue by solvent deasphalting and
this deasphalted oil may be subjected to catalytic cracking in the
presence or absence of hydrogen. Another option is to separate an
atmospheric residue-into a vacuum distillate and a vacuum residue
by vacuum distillation, to separate a deasphalted oil frcm the
vacuum residue by solvent deasphalting and to subject both the
vacuum distillate and the deasphalted oil to catalytic cracking in
the presence or absence of hydrogen.
Solvent deasphalting (DA), a process in which an asphaltenes-
containing feedstock is converted into a product from which a
deasphalted oil can be separated as the desired main product and
an asphaltic bitumen as a by-product, has proven in actual prac-
tice to be a suitable treatment for ~he production of deasphalted
oils from a variety of asphaltenes-containing hydrocarbon mlx-
tures.
It has now been investigated whether combining the DA treat-
ment with a pretreatment of the asphaltenes-containing feed and/or
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an aftertreatment of the asphaltic bitumen separated in the DA
treatment and using at least part of the asphaltic bitumen that
has been subjected to the aftertreatment as the feed for the DA,
might yield better results than employing nothing but the DA. In
the assessment of the results the yields of deasphalted oil and
light product(s) are most important. m e qualities of the de-
asphalted oil and the light product(s) as well as the quality of
the heavy by-product are also important. In this context the
quality of the deasphalted oil is taken to be its sultability for
co~lversion into hydrocarbon oil distillates by catalytic cracking
in the presence or absence of hydrogen. This suitability is
greater according as the deasphalted oil has, among other things,
lcwer asphaltenes, metal and sulphur contents. In this context the
quality of the light product is taken to be its suitability for
processing into a valuable light fuel. m is suitability is greater
according as the light product has, among other things, lower
sulphur and olefins contents. In this context the quality of the
heavy product is taken to be its suitability for serving as a fuel
oil co~lponent. This suitability is greater according as the heavy
product has, among other things, lcwer metal and sulphur contents
and lower viscosity and density. For use as pretreatments of the
feed for the DA and as aftertreatments of the asphaltic bitum~n
separated in the DA, the follcwing treatments were investigatedo
thermal cracking (TC) in which a heavy feed is converted into a
product which contains less than 20 %w C4 hydrocarbons and from
which one or more distillate fractions and a heavy fraction are
separated and catalytic hydrotreatment (Hr~ in which an as-
phaltenes-containing feed is converted into a product having a
reduced asphaltenes content from which one or more distillate
3o fractions and a heavy fraction are separated.
During this investigation a ccmparison was made between the
results that can be obtained when a deasphalted oil and possibly a
hydrocarbon oil distillate having a given boiling xange as well as
a heavy by-product are produced starting from equal quantities of
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an asphaltenes-containing hydrocarbon mI~ture by using a) DA only,
b) DA in ccmbination with TC, c) DA in ccmbination with HT and d)
DA in combination with both TC and HT, the conditions of the
various treatments being similar as much as possible. In view of
quantity and quality of the deasphalted oil and the hydroc æbon
oil distillate to be obtained in each of the procedures and the
quality of the heavy by-product, the various procedures may be
arranged as follcws:
Quantity of deasphalted oil d = c > b = a
10 Quality of the deasphalted oil d = c > b = a
Quantity of hydrocarbon oil distillate d > c > b
Quality of the hydrocarbon oil distillate c > d > b
Quality of the heavy product c > d > a > b
Taking into account the considerable difference in hydro-
carbon oil distillate yields obtained according to procedures c)
and d) and the no more than minor differences in quality between
the hydrocarbon oil distillates and between the heavy by-products
obtained according to procedures c) and d) a procedure in which a
co~bination is used of a DA treatment, a TC treatment and a HT, is
much preferred.
As regards the order in which the three treatments are
carried out, a number of embodiments may be considered. Each of
the embodiments may be placed in one of the two follcwing classes.
I. m e asphalte~es-containing feed is first subjected to a HT or
a DA treatment and the heavy fraction or asphaltic bitumen
separated from the respective products obtained, is subjected
to a combination o a ~A treatrnent and a TC treatment or a
combination of a TC treatment and a HT, respectively.
II. The asphaltenes-containing feed is first subjected to a TC
treatment and the heavy fraction separated from the product
obtained is subjected to a combination of a D~ treatment and
a HT.
The em~xx~ments belonging to class I constitute the subject
matter of the present patent application.
iL2~ 5~
m e e~bodiments to which the present patent application
relates, may be subdivided further depending on whether the
asphaltenes-containing feed is used as a feed component for the HT
(class IA), or as a feed ccmponent for the DA treatment (class B).
In all the embodiments the asphaltic bitumen fraction which is
separated from the product of the DA treatment is used as the feed
for the TC treatment. In the embodiments belonging to class IA
the heavy fraction which is separated from the product of the TC
treatmPnt is used as a feed ccmponent for the HT and the heavy
fraction which is separated frcm the product of the HT is used as
the feed for the DA treatment. In the rmbodim nts belonging to
class IB the heavy fraction which is separated from the product of
the HT is used as a feed ccmponent for the DA treatment and the
heavy fraction which is separated from the product of the TC
treatment is used as the feed for the HT.
The present patent application therefore relates to a process
for the production of deasphalted oils and hydrocarbon oil distil-
lates from asphaltenes-containing hydrocarbon mixtures, in which
an asphaltenes-containing hydrocarbon mixture (stream 1) is
subjected to a combination of the following three trea~ments: a
catalytic hydrotreatment (HT) in which an asphaltenes-containing
feed is converted into a product having a reduced asphaltenes
content, from which one or more distillate fractions and a heavy
fraction (stream 2) are separated, a solvent deasphalting (DA)
treatment in which an asphaltenes-containing feed is converted
into a prcxluct from which a deasphalted oil and an asphaltic
bitumen (stre~m 3) are separated and a thermal cracking treatment
(TC) in which a feed is converted into a product whi.ch conta.ins
3 less than 20 ~w C4 hydrocarbons and fro.m which one or more
distillate fractions and a heavy fraction (stream 4) are se-
parated, in which stream 3 is used as the feed for the TC treat-
ment and stream 1 is used either
1) together with stream 4 as a feed component for the HT with
stream 2 being used as the feed for the DA treatment, or
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2) together with stream 2 as a feed ccmponent for the DA treatment
with stream 4 being used as the feed for the HT.
In the process according to the invention the feed used is an
asphaltenes-containing hydroc æbon mlxture. A suitable parameter for
assessing the asphaltenes content of a hydrocarbon mixture and the
reduction of the asphaltenes content which occurs when an as-
phaltenes-containing hydrocarbon muxture is subjected to a ~, is
the Ramsbotb~m Carbon Test value ~RCT)~ m e higher the asphaltenes
content of the hydrocarbon mixture, the higher the RfT. Preferably
the process is applied to hydrocarbon muxtures which boil sub-
stantially above 350C and more than 35 %w of which boils above
520C and which have an RCT higher than 7.5 %w. Examples of such
hydrocarbon mixtures are residues obtained in the distillation of
crude mineral oils and also heavy hydorcarbon mlxtures obtained
f mm shale and tar sands. If desired, the process may also be
applied ~o heavy crude mineral oils, residues obtained in the
distillation of products formed in the thermal cracking of hydro-
carbon mixtures and asphaltic bitumen obtained in the solvent de-
asphalting of asphaltenes-containing hydroca~bon muxturesO The
process according to the invention can very suitably be applied to
residues obtained in the vacuum distillation of a~mospheric
distillation residues from crude mineral oils. If the feed avail~-
ble for the process according to the invention is an atmospheric
distillation residue frcm a crude mineral oil, it is preferred to
separate a vacuum distillate therefrQm by vacuum distillation and
to subject the resulting vacuum residue to ~he process according
to the invention. The separated vacuum distillate may he subjected
to the~mal cracking or to catalytic cracking in the presence or
absence of hydrogen to convert it into light hydrocarbon oil
distillates.
The process according to the invention is a three-step
process in which an asphaltenes-containing feed (stream 1) is
subjected in the first step to a ~ or a DA treatment and in which
the heavy fraction (stream 2) and the asphaltic bikumen (stream 3)
5~
separated frcm the product obtained by the respective treatments
are subjected in the second and the third step of the process to a
combination of a DA treatment and a TC treatment and a combination
of a TC treatment and a HT, respectively.
Asphaltenes-containing hydrocarbon mLxtures usually include a
considerable percentage of metals, particularly vanadium and
nickel. When such hydrocarbon mixtures are subjected to a cata-
lytic treatment, for instance a HT for the reduction of the
asphaltenes content as is the case in the process according to the
invention, these metals will be deposited on the catalyst used in
the HT, thus shortening its useful lifeO In view of this, as-
phaltenes-containing hydrocarbon mixtures having a vanadium +
nickel content higher than 50 parts per million by weight (ppmw)
should preferably be subjected to a demetallization treatment
before being contacted with the catalyst used in the HT. This
demet~llization may very suitably be carried out by contacting the
asphaltenes-containing hydrocarbon mixture in the presence of
hydrogen with a catalyst more than 80 ~w of which consists of
silica. Both catalysts consisting entirely of silica and catalysts
containing one or more metals with hydrogenation activity - in
particular a ccmbination of nickel and vanadium - supported on a
carrier consisting substantially of silica, are suitable for the
purp~se. When in the process according to the invention an as-
phaltenes-containing feed is subjected to a catalytic demetal-
lization treatment in the presence of hydrogen, this demetal-
lization may be carried out in a separate reactor. Since the
catalytic demetallization and the HT for the reduction of the
asphaltenes content can be carried out under the same conditions,
the two processes may also very suitably be carried out in the
3o same reactor, which successi~ely contains a bed of the demetalli-
zation reactor and a bed of the catalyst used in the EIT.
Suitable catalysts for carrying out the ~T are those which
contain at least one metal chosen from the group formed bv nickel
and cobalt and in addition at least one metal chosen from the
group formed by molybdenum and tungsten supported on a carrier,
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which carrier conslsts more than 40 %w of alumina.
Very suitable catalysts for use in the HT are those which comprise
the metal combination nickel/molybdenum or cobalt/molybdenum
supported on alumina as the carrier. The HT is preferably carried
out at a temperature of from 300-500C and in particular of from
350-450C, a pressure of fr~n 50-300 bar and in particular of from
75-200 bar, a space velocity of f m m 0.02-10 g.g 1.h 1 and in
particular of from 0.1-2 g.g 1.h 1 and a H~/eed ratio of
from 100-5000 Nl.kg 1 and in particular of from 500-2000 Nl.kg 1.
The same preference applies to the conditions which are used in a
possible catalytic demetallization in the presence of hydrogen as
to those given hereinbefore for the HT aiming at reduction of the
asphaltenes content.
The HT is preferably carried out in such a manner that it
yields a product, the C5+ fraction of which meets the follow-
ing requirements:
a) the RCT of the C5 fraction amounts to 20-70% of the RCT of
the feed, and
b) the difference between the percentages by weight of hydro-
carbons boiling below 350C present in the C5~ fraction and
in the feed is at most 40.
I~ should be noted that in the catalytic demetallization the
reduction of the metal content is accompanied by some reduction of
the ~CT and some formation o C5-350C product. A similax pheno-
menon occurs in the HT in which the reduction of the ~CT and the
formation of C5-350C product are accompanied by some reduction
of the met~l content. The requirements mentioned hereinbefore
under a) and b) bear upon the overall reduction of R~T and for-
mation of C5-350~C product (viz. including those occuring in a
possible catalytic demetallization trPatment).
The HT yields a product with a reduced asphaltenes content
fram which one or rnore distillate fractions and a heavy fraction
(stream 2) are separated. The distillate fractions separated from
the product may be only atmosph~ric distillates, but preferably a
vacuum distillate should be separated from the product as well.
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This vacuum distillate may be converted into light hydrocarbon oil
distillates in the ways mentioned hereinbefore.
In the process according to the invention instead of a HT the
first step applied may be a DA treatment in which an asphaltenes-
containing feed is converted into a product from which a de-
asphalted oil and an asphaltic bitumen (stream 3) are separated.
Suitable solvents for carrying out the DA treatment are paraffinic
hydrocarbons having 3-6 carbon atcms per molecule, such as n-bu-
tane and mixtures thereof, such as mixtures of propane and n-bu-
tane and mixt~lres of n-butane and n-pentane. Suitable solvent/oil
weight ratios lie in the range of from 7:1 to 1:1 and in par-
ticular of from 4:1 to 1:1. m e ~A treatment is preferably carried
out at a pressure in the range of from 20-100 bar. When n-butane
is used as the solven~, the deasphalting is preferably carried out
at a pres Æ e of frcm 35-45 b æ and a temperature of from 100-
150C.
In the process according to the invention the second or thi~d
step used is a TC treatment in which stream 3 is converted into a
product which contains less than 20 %w C4 hydroc æbons and
frcm which one or more distillate fractions and a heavy fraction
(stream 4) are separated. The distillate fractions separated from
the product may be only atmospheric distillates, but preferably a
vacuum distillate should be separated frcm the product as well.
This vacuum distillate may be convert d into light h~droc æbon oil
distillates in the manners indicated hereinbefore. The TC treat-
ment is preferably carried out at a temperature of frcm 400~525C
and a space velocity of frcm 0.01-5 kg frebh feed per litre crack-
ing reactor volume per munute.
As stated hexeinbefore, the embodiments belonging to class I
3 to which the present patent application relates are subdivided
depending on whether stream 1 is used as a feed compo~ent for the
(class IA) or as a feed ccmponent for the DA treabment (class
IB).
5~
m e embodiment belonging to class IA is represented schema-
tically in Figure I~ The various streams, fractions and reaction
zones are indicated by three digit numbers, ~he first of which
refers to the Figure concerned. m e vacuum residue ~302), for
instance, refers to vacuum residue 2 in the context of Figure III.
According to Figure I the process is carried out in an ap-
paratus comprising a HT zone (105), a DA zone (106) and a TC zone
(107), successively. An asphaltenes-containing hydrocarbon mixture
(101) and a residual fraction (104) are subjected to a ~ and the
hydrotreated product is separated into one or more distillate
fractions (108) and a residual fraction (102). Stream 102 is
subjected to a DA treatment and the product is separated into a
deasphalted oil (109) and an asphaltic bitumen (103). Stream 103
is suhjected to TC and the cracked product is separated into one
or more distillate fractions (110) and a residual raction (104).
The embcdiment belonging to class IB is represented schema-
tically in Figure II. According to this Figure the process is
carried out in an apparatus consisting of a DA zone (2051, a TC
zone (206) and a ~ zone (207), successively. An asphaltenes-
containing hydrocarbon mixture (201) and a residual fraction (202)
are subjected to a DA treatment and the product is separated into
a deasphalted oil (208) and an asphaltic bitumen (203). Stream 203
is subjected to a TC treatment and the cracked product is se-
parated into one or more distillate fractions (209) and a residual
fraction (204). Stream 204 is subjected to a HT and the hy~ro-
treated product is separated into one or more distillate fractions
(210) and a residual fraction (202).
In the enbodiments wher~ it is the object to achieve the
cGmpletest possible ccnversion of stream (.01) into deasphalted
3o oil and hydrocarbon oil distillates, a so-called "bleed stream"
should preferably be separated from one of the heavy streams of
the process. In this way the build-up of undesirable heavy compo,
nents during the process can be obviated.
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Two flow diagrams for the preparation of deasphalt.ed oil and
hydrocarbon oil distillates from asphaltenes-containing hydro~
carbon muxtures according to the invention will hereinafter be
explained in more detail with t,he aid of Figures III and IV.
Flow diagram A (based on embodiment IA)
See Figure III.
The process is carried out in an apparatus ccmprising succesively,
a HT zone camposed of a unit for catalytic hydrotreatment (305), a
unit for atmospheric distillation (306) and a vacuum distillation
unit (307), a DA zone (308) and a TC zone comp~sed of a ~hermal
cracking unit (309), a second at~ ~p~er.ic distillation unit (310)
and a second vacuum distillation Ullit ~311). A~ asphaltenes-
containing hydrocarbon mlxture (3013 is ~xed with a recirculation
stream (312) and the mlxture (313) is subjected together with
hydrogen (314) to a catalytic hydrotreatment. The hydrotreated
product (315) is separated by atmospheric distillation into a gas
fraction (316), an atomospheric distillate (317) and an abmos-
pheric residue (318)~ T.he atmospheric residue (318) is separated
by vacuum distillation into a vacuum distillate (319) and a vacuum
residue (302). m e vacuum residue (302) is separated by solvent
deasphalting into a deasphalted oil (320) and an asphaltic bitumen
(303). The asphaltic bitumen ~303) is subjected to thermal crack-
ing and the thermally cracked product (321) is separated by
atmospheric distillation into a gas fraction (322), an atmospheric
distillate (323) and an atmospheric residue (324). The atmospheric
residue (324) is separated by vacuum distillation into a vacuum
distillate (325) and a vacuum residue (304). The vacuum residue
(304) is divided into two portions (312) and (326).
Flow diagram B (based on embodiment IB)
See Figure rv.
The process is carried out in an apparatus camprising, successive-
ly, a DA zone (405), a TC zone composed of a thermal cracking unit
(406), an abmospheric distillation unit (407) and a vacuum
~Z~5~
distillation unit (408) and a HT zone composed of a unit for
catalytic hydrotreatment (409), a second atmospheric distillation
unit (410) and a second vacuum distillation unit (411). An as-
phaltenes-containing hydrocarbon mixture (401) is muxed with a
vacuum residue (402) and the mixture (412) is separated by solvent
deasphalting into a deasphalted oil (413) and an asphaltic bitumen
(403). The asphaltic bitumen (403) is subjected to ther~al crack-
ing and the thermally cracked product (414) is separated by
atmospheric distillation into a gas fraction (415), an atmospheric
distillate (416) and an atmospheric residue (417~. The atmospheric
residue (417) is separated by vacuum distillation into a vacuum
distillate (418) and a vacuum residue (404). The vacuum residue
(404) is divided into two portions (419) and (420). Portion (420)
is subjected together with hydrogen (421) to a catalytic hydro-
treatm~nt. m e hydrotreated product (422) is separated by atmos-
pheric distillation into a gas fraction (423), an atmospheric
distillate (424) and an atmosph~ric residue (425). m e atmospheric
residue (425) is separated by vacuum distillation into a vacuum
distillate (426) and vacuum residue (402).
The present patent application also includes apparatuses for
carrying out the process according to the invention substantially
corresponding with those represented schematically in Figures I-
IV.
The invention is now elucidated with the aid of the follcwing
Examples.
In the process according to the invention two asphaltenes-
containing hydrocarbon mlxtures obtained as residues in the vacuum
distillation of atmospheric distillation residues frcm crude
m m eral oils were used as the starting material~ m e two vacuum
residues both boiled substantially above 520~ and they had RCT's
of 19.1 and 15~8 %w, respectively. m e process was carried out
according to flcw diagrams A and B. m e conditions used in the
various zones were the follcwing.
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m e unit for catalytic hydrotreatment as described in both
the flow diagrams consisted of two reactors, the first of which
was filled with a Ni/V/Sio2 catalyst containing 0.5 parts by
weight (pbw) nickel and 2.0 pbw vanadium per 100 pbw silica and
the second of which was filled with a Co/MD/A1203 catalyst
containing 4 pbw cobalt and 12 pbw molybdenum per 100 pbw alumina.
m e catalysts were used in a 1:4 volume ratio. The HT was carried
out at a hydrogen pressure of 150 bar, a space velocity (measured
over the two reactors) of 0.5 kg feed per litre catalyst per hour,
a H2/feed ratio of 1000 Nl per kg and an average temperature of
410C in the first reactor and 385C in the second reactor.
In both the flow diagrams the DA treatment was carried ou~
using n-butane as solvent, at a temperature of 115C, a pressure
of 40 bar and a solvent/oil weight ratio of 3:1.
In both the flow diagrams the TC treatment was carried out in
a cracking coil, at a pressure of 10 bar, a space velocity of 0.4
kg fresh fee~ per litre cracking coil volume per minute and a
temperature of S00C (temperature measured at the outlet of the
cracking coil~.
Example 1
This Example was carried out according to flow diagram A as
represented by Figure III.
100 pbw ~acuum residue (301) having an RCT of 19.1 %w yielded
the various streams in the follcwing ~uantities:
102.2 pbw mixture (313) having an ~CT of 19.5 %w, a product
(315), the C5+ fraction of which had an RCT of g.4 %w,
20.7 pbw C5-350C atmospheric distillate ~317),
75.1 " 350C atmospheric residue (318),
30.1 " 350-520C vacuum distillate (319),
45 0 " 520C+ vacuum residue (302),
30.6 " deasphalted oil (320),
14.4 " asphaltic bitumen (303),
2.3 " C5-350C atmospheric distillate ~323),
11.7 " 350~ atmospheric residue (324),
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1.5 pbw 350-520C vacuum distillate (325),
10.2 " 520C~ vacuum .residue (304),
2.2 " portion (312) and
8.0 " portion (326).
Example 2
This Example was carried out according to f1GW diagram B as
represented by Figure IV.
100 pbw Vacuum residue (401) having an RCT of 19.8 ~w
yielded the various streams in the following quantities:
117.6 pbw mixture (412),
71.7 " deasphalted oil (413),
45.9 " asphaltic bitumen (403)
5.9 " C5-350C atm~spheric distillate (416),
31.9 " 350C abmospheric residue (417~,
4'7 " 350-520C vacuum distillate (418),
34.4 " 520C~ vac~um residue (404),
5.0 " portion (419),
29~4 " portion (420) having an R~T of 41.2 %w,
a product (422~, the C5 fraction of which had an RCT of
18.5 %w,
4.1 pbw C5-350C atm3spheric distillate (424),
23.8 " 350C atm3sph~ric residue (425),
6.2 " 350-520C vacuum distillate (426) and
17.6 " 520C vacuum residue (402).
