Note: Descriptions are shown in the official language in which they were submitted.
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1 BACKGROUND OF THE INVE~lTION
2 1. Field of the Invention
3 The present invention relates to an improve-
4 ment in a combination visbreaking and hydrorefining
process for upgrading hydrocarbonaceous oils.
6 2. Description of the Prior Art
7 Visbreaking is a well-known mild thermal
8 cracking process to which heavy hydrocarbonaceous oils
9 may be subjected to reduce their viscosity by depoly-
merization and cracking in the liquid phase. See, for
11 example, Hydrocarbon Processing, September 1978, page
12 106.
13 The term "hydrorefining" is used herein to
14 designate a catalytic treatment conducted in the
presence of added hydrogen, of a hydrocarbonaceous oil
16 to upgrade the oil by eliminating or reducing the
17 concentration of contaminants in the oil such as s~lfur
18 compounds, nitrogenous compounds and metal contami-
19 nants, hydrogenation of unsaturated constituents of the
oil and conversion of at least a portion of the heavy
21 constituents of the oil.
22 U.S. Patent 2,321,841 discloses visbreaking
23 a heavy hydrocarbonaceous oil and thereafter non-
24 destructively catalytically hydrogenating the visbroken
oil. The hydrogenated bottoms may be recycled to the
26 visbreaking zone.
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1 U.S. Patent 3,338,8'0 discloses hydrovis-
2 breaking a hydrocarbonaceous oil. The lighter fraction
3 of the hydrovisbroken oil is catalytically hydro~
4 genated. The hydrogenated bottoms are recycled to the
hydrovisbreaking zone.
6 U.S. Patent 3,050,457 discloses hydrovis-
7 breaking a crude shale oll and catalytically hydro-
8 genating the light fraction. The overhead gases are
g recycled from the hydrogenation zone to the hydro-
visbreaking zone.
11 U.S. Patent 3,132,088 discloses visbreaking
12 a residual oil and catalytically hydrogenating the
13 deasphalted bottoms of the visbroken oil.
14 It has now been found that a combination
visbreaking, hydrorefining at conditions to convert at
16 least a portion of the heavy constituents of the
17 visbroken oil and a recycling of the hydrorefined
18 bottoms to the visbreaking zone will provide advantages
19 that will become apparent in the ensuing description.
SUMMARY OF THE INVENTION
21 In accordance with the invention there is
22 provided, a process for upgrading a heavy hydrocar-
23 bonaceous oil which comprises the steps of:
24 (a) treating a chargestock comprising a
fresh heavy hydrocarbonaceous oil comprising at least
26 about 10 volume percent materials boiling above 1050F
27 and a hydrorefined bottoms fraction recycled from step
28 (d) in a visbreaking zone at visbreaking conditions to
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1 produce a visbroken oil product, s~id visbroken oil
2 comprising materials boiling above 1050F;
3 (b) contacting at least a portion of said
4 visbroken oil with a hydrorefining catalyst in the
presence of added hydrogen in a hydrorefining zone at
6 hydrorefining conditions such as to convert at least
7 about 5 weight percent of the materials boiling above
8 10s0F of said visbroken oil to lower boiling hydro-
9 carbons, said hydrorefining conditions including a
hydrogen partial pressure of at least 1000 psig, to
11 produce a hydrorefined effluent including a normally
12 gaseous phase and a normally liquid phase, including
13 normally liquid hydrocarbons;
14 (c) separating the hydrorefined oil product
resulting from step (b) into fractions, including a
16 hydrorefined heavy bottoms fraction, and
17 (d) recycling at least a portion of the
18 separated hydrorefined heavy bottoms fraction to said
19 visbreaking zone.
By the terms "normally liquid" and "normally
21 gaseous" are intended herein that the components are
22 liquid or gaseous, respectively, at standard tempera-
23 ture and pressure conditions.
24 BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic flow plan of one
26 embodiment of the invention.
27 Figure 2 is a schematic flow plan of another
28 embodiment of the invention.
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1 Figure 3 is a graph showing effect of
2 recycle on residuum yield and toluene insoluble in
3 visbreaking.
4 Figure 4 is a graph showing effect of
recycle on residuum conversion and toluene insoluble in
6 visbreaking.
7 DESCRIPTION OF THE PREFERRED EMBODIMENTS
. _ .... _ .
8 Referring to Figure 1, a fresh heavy
9 hydrocarbonaceous oil comprising materials boiling
above 1050F and a recycled hydrorefined bottoms
11 fraction (line 44) are passed by line 10 into vis-
12 breaking zone 12. All boiling points referred to
13 herein unless otherwise specified are atmospheric
14 pressure boiling points.
Fresh Heavy Hydrocarbon Oils
16 Suitable fresh heavy hydrocarbon oils for
17 the visbreaking zone of the present invention are:
18 hydrocarbonaceous oils comprising at least 10 volume
19 percent materials boiling above about 1050F, pre-
ferably at least 25 volume percent boiling above
21 1050F. The 1050F+ materials generally include
22 asphaltenes. The initial boiling point of such oils
23 will generally range from about 550 to 650F, although
24 whole crude oils may be used. Suitable oil feeds for
the visbreaking zone include heavy crude mineral oils;
26 residual petroleum fractions such as atmospheric
27 residua and vacuum residua. Such oil feeds usually
28 contain large amounts of sulfur and may contain
29 metallic contaminants such as nickel and vanadium. The
total metal content of such oils may range up to 2000
31 weight part per million or more, and the sulfur content
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1 may rang^ from at least 0.5 weight percent to 8 weigil~
2 percent or more. The Conradson carbon residue of the
3 oils will be above 2 weight percent, preferably from 5
4 to 50 weight percent, and more preferably above 7
weight percent (as to Conradson carbon, see ASTM Test D
6 189-65). The heavy hydrocarbon oil may be derived from
7 any source such as petroleum, shale oil, tar sand oil,
8 heavy oils produced by coal liquefaction processes,
9 etc., and mixtures thereof. The preferred oil feed is
a petroleum residuum obtained from distillation or
11 other treating or separation process.
12 Visbreak ng Operating Conditions
13 Suitable visbreaking conditions in vis-
14 breaking zone 12 include a temperature ranging from
about 750 to 950F, preferably from about 800 to about
16 920F, a pressure ranging from 50 to 1500 psig,
17 preferably from 100 to 1000 psig, more preferably from
18 200 to 800 psig. The visbreaking zone may be a coil
19 disposed in a furnace. In such an embodiment, the
stated temperatures refer to coil outlet temperatures
21 and the preferred pressures are coil outlet pressures
22 ranging from 200 to 800 psig. If desired, a hydrogen-
23 containing gas may be introduced into the visbreaking
24 zone to conduct hydrovisbreaking. The heavy hydrocar-
bonaceous oil chargestock is maintained at visbreaking
26 conditions only for a time sufficient to convert not
27 more than 50 volume percent of the 700F+ constituents
28 to products boiling below 700F. Under the above
29 conditions, the heavy oil chargestock is partially
converted to lower boiling hydrocarbon products. The
31 effluent of the visbreaking zone is passed by line 14
32 to separation zone 16, which may be a flash zone,
33 wherein the lighter boiling materials are removed
34 overhead by line 18 and the heavier visbroken oil
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1 product is removed by line 20, mixed with a hydrogen-
2 containing gas, preferably containing more than 70
3 percent hydrogen, introduced into line 20 by line 22
4 and passed into hydror~fining zone 24. The initial
boiling point of the visbroken oil removed by line 20
6 from separation zone 16 may range from 100 to 1000F.
7 The visbroken oil portion introduced into hydrorefining
8 zone 24 comprises unsaturated hydrocarbons, materials
9 boiling above 1050F and usually sulfur contaminants.
The Hydrorefining Catalyst
11 The hydrorefining catalyst present in
12 hydrorefining zone 24 can be any conventional hydro-
13 refining catalyst. Suitable hydrorefining catalysts
14 include a hydrogenation component, such as a Group VIB
and a Group VIII metal, metal oxide, metal sulfide and
16 mixtures thereof, composited with a support, such as an
17 alumina-containing support. The catalyst may be, for
18 example, a catalyst comprising cobalt, mDlybdenum,
19 nickel, tungsten and mixtures thereof on an alumina
support, which may additionally comprise phosphorus
21 and/or silica. Suitable catalysts are described, for
22 example, in U.S. Patents 3,770,618; 3,509,044 and
23 4,113,656
24
Suitable operating conditions in the
26 hydrorefining zone are summarized in Table I.
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1 T~BLE I
2 HYDROREFINING OPERATING CONDITIONS
3 Conditions Broad ~ange Preferred Range
4 Temperature, F 600-850 650-800
5 Total pressure, psig 1000-3000 1000-2500
6 Liquid hourly space
7 velocity, V/V/HR0.05-5.0 0.1-2.5
8 Hydrogen Rate, SCF/BBL 300-10,000 2000-6000
9 Hydrogen partial
10 pressure, psig1000-3000 1000-2000
11 The hydrorefining zone is operated at
12 conditions, including a hydrogen partial pressure of at
13 least 1000 psig, such that at least about 5 weight
14 percent, preferably more than 10 weight percent of the
1050F+ materials of the portion of the visbroken oil
16 introduced into the hydrorefining zone is converted to
17 lower boiling hydrocarbon products while simultaneously
18 hydrogenating unsaturated hydrocarbons, converting
19 asphaltenes to non-asphaltenes, and desulfurizing, and
demetallizing the visbroken oil. The hydrorefining
21 zone effluent is passed by line 26 to separation zone
22 28 wherein a normally gaseous phase, including hydro-
23 gen, hydrogen sulfide, light hydrocarbon gases and
24 which may comprise ammonia, is separated from a
normally liquid phase which includes normally liquid
26 hydrorefined hydrocarbon oil. The normally gaseous
27 phase is removed from separation zone 26 by line 30. If
28 desired, hydrogen sulfide may be removed by conven-
29 tional methods from the gaseous phase recovered by line
and the substantially hydrogen-sulfide free
31 hydrogen-containing gas may be recycled to hydro-
32 refining zone 24. Optionally, the hydrogen-containing
33 gaseous phase recovered by line 30 may be recycled to
34 visbreaking zone 12 with or without prior hydrogen
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1 sulfide removal. The hyd orefined oil product is
2 removed by line 32 and passed to separation zone 34
3 such as a fractional distillation zone, to separate the
4 oil into light gases removed overhead by line 36, a
naphtha fraction recovered by line 38, an intermediate
6 boiling fraction recovered by line 40 and a heavy
7 hydrorefined bottoms fraction comprising material
8 boiling above 1050F removed by line 42. At least a
9 portion of the bottoms fraction is recycled by line 44
to line 10 in which is carried a fresh heavy oil feed
11 for introduction into visbreaking zone 12. The bottoms
12 fraction is recycled at a volumetric ratio of bottoms
13 fraction to fresh oil feed ranging from 0.1:1 to 5:1,
14 preferably at a volumetric ratio ranging from 0.5:1 to
lS 2:1. If desired, a portion of the intermediate
16 fraction may also be recycled to the visbreaking zone
17 12 via line 46.
18 The figure 2 embodiment differs from the
19 figure 1 embodiment in that the hydrogen and hydrogen
sulfide-containing gas recovered from the hydrorefining
21 zone effluent is recycled to the visbreaking zone which
22 is operated as a hydrovisbreaking process. Hydrogen
23 sulfide is removed from the gases recovered from the
24 hydrovisbreaking effluent and the substantially
hydrogen sulfide free hydrogen-containing gas is
26 recycled to the hydrorefining zone. Referring to
27 Figure 2, a fresh heavy oil feed of the same type as
28 described with reference to Figure 1 is passed by line
29 110 to hydrovisbreaking zone 112. The hydrovisbreaking
zone effluent is passed by line 114 to separation zone
31 116 (such as a flash zone1 wherein a normally gaseous
32 phase is separated from a normally liquid phase. The
33 gaseous phase is passed by line 118 to separation zone
34 119 in which a gaseous phase is separated from a
normally liquid hydrocarbon phase. The hydrogen and
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g
1 hydrogen sulfide-containing gaseo~s phase is removed by
2 line 121. If desired, hydrogen sulfide may be removed
3 from the gaseous phase and the resulting hydrogen-
4 containing gas may be recycled to line 122. The
normally liquid hydrocarbon phase is recovered by line
6 123. The liquid hydrovisbroken oil from separation
7 zone 116 is passed by line 120 to hydrorefining zone
8 124. A fresh or recycled hydrogen-containing gas or
9 mixtures thereof is introduced into line 120 by line
122. Hydrorefining zone 124 is operated at the same
11 conditions and comprises the same type of hydrorefining
12 catalyst as described with reference to Figure 1. The
13 hydrorefining zone effluent is passed by line 126 to
1~ separation zone 128 wherein a gaseous phase is sepa-
rated from the hydrorefined oil phase. The gaseous
16 phase, which comprises hydrogen, hydrogen sulfide,
17 ammonia and light gaseous hydrocarbons, is removed by
18 line 130 and passed by line 131 into oil feed line 110
19 for introduction into the hydrovisbreaking zone 112.
The hydrorefined oil is passed by line 132 into
21 separation zone 134 in which it is separated into
22 fractions. Light gases are removed by line 136. A
23 naptha fraction is removed by line 138. An inter-
24 mediate boiling fraction is removed by line 140. The
hydrorefined bottoms fraction, comprising materials
26 boiling above 1050F, is removed by line 142 and
27 recycled by line 144 to fresh oil feed line 110 in the
28 same volumetric ratio as previously described with
29 reference to Figure 1. If desired, a portion of the
intermediate fraction 140 may be recycled to oil feed
31 line 110 by line 144.
32 The following examples are presented to
33 illustrate the invention.
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1 ~AMPLE 1
2 A fresh virgin whole Cold Lake crude oil was
3 visbroken. The visbroken product was distilled to
4 obtain a 300C+ (572F+) residuum. The visbroken
residuum was hydrorefined utilizing a conventional
6 cobalt-molybdenum on alumina hydrorefining catalyst.
7 The total hydrorefined liquid product was distilled to
8 obtain a 510C+ (950F+) hydrorefined bottoms portion.
9 These steps represent a first-pass operation. The
operating conditions and results of these process steps
11 are summarized in Table II. The hydrorefined bottoms
12 fraction (recycle) and fresh whole Cold Lake crude oil
13 were blended in a volumetric ratio of 1:2. The blend
14 was visbroken. Visbreaking of the blend simulates a
second-pass operation in accordance with the present
16 invention. Table II summarizes data for a typical
17 second-pass visbreaking which includes the recycle
18 hydrorefined bottoms portion. The conversion of 510C+
19 on fresh feed (recycle free basis) was 58 LV~, in
contrast to 31 LV% obtained without recycle.
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1 TABLE II
2DATA FROM FIRST-PASS OF VISBREAKING
3 AND HYDROREFINING OPERATION
4 FIRST-PASS
5 PROCESS STEP VISBREAKING HYDROREFINING
6 STREAM FEED PRODUCT PRODVCT
7 CUT TEMPERATURE (WHOLE (TOTAL FEED (TOTAL
8 CRUDE) LIQUID) (5720F+) LIQUID)
9 Total Stream
10 Gravity, API at
11 at 60F 10.3 13.7 6.4 16.4
12 Carbon, wt% 82.25 -- -- 87.29
13 Hydrogen, wt% 10.59 ~ 11.16
14 Sulphur, wt% 4.43 4.36 4.51 0 795
15 Nitrogen, wt% 0.41 -- 0.51 0 32
16 CCR(l~, wt% 13.1 14.8 18.2 8.3
17 NI (2), wt% 12.7 12.7 16.2 6.4
18 Metals, wppm
19 Nickel 77 77 99 27.1
20 Vanadium 190 190 245 54.2
21 950F+ Residuum
22 Yield, LV% 54 0 37 4 5 37.8
23 Sulphur, wt% 5.8 5.4 5.5 1.79
24 CCR, wt% 22.9 35.8 35.8 20.4
25 NI, wt% 22.2 30.7 30.7 --
Metals, wppm
26 Nickel 135 186 186 67
27 Vanadium 333 459 459 133
28 Conversion of 950F+
29 LV% -- 30.7 -- 24.2
30 wt% -- 27.5 -- 22.8
31 Operating Conditions
32 Tempërature, F -- 838 -- 700-734
33 Space Velocity,
34 v/h/V __ 5-10 -- 0.3-0.6
35 H2 Pressure, psi __ 200 -- 2000
36 H2 Rate, SCF/B -- Nil -- 6000
37 % Desulphurization 82.4
38 % Denitrogenation 37.3
39 % Nickel removal 72.6
40 % Vanadium removal 77 9
41 % CCR(l) removal 54 4
4 % NI(2) removal 60.5
...... _
43 (1) CCR denotes Conradson carbon residue
44 (2) NI denotes naphtha insolubes
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1TABLE III
2DATA FROM SECOND-PASS OF VISBREAKING OPERATION
3SECOND-PASS VISBREAKING
4 FEED
5FRESH RECYCLE
6FEED tHYDRO- TOTAL PRODUCT
7 STREAM (WHOLE GENATED FEED (TOTAL
8 CRUDE) 950F+) (BLEND) LIQUID)
9 Yield, LV% 67.2 32.8 100 101.9
Yield, WT% 66.7 33 3 100 99.7
11 Gravity, OAPI at 60F 10.3 5.9 9 4 12.5
12
13 Carbon, wt% 82.26 -- 83.79
14 Hydrogen, wt% 10.59 --- 10.23 0.17
Sulphur, wt% 4.43 1.79 3.55 --
Nitrogen, wt% 0.41 --
17 Toluene insolubles, wt% Nil Nil Nil 0.1
18 CCR(l), wt% 13.1 20.4 15.5 17.5
19 NI(2), wt% 12.7 15.7 13.7 14.1
20 Metals, wppm
21 Nickel 77 67 74 74
22 Vanadium 190 133 171 171
23 Yield of 675F+, LV% 82.5 100 88.2 74.6
24 Yield of 950F+, LV% 54.0 100 69.0 48
, wt% 57.1 100 71.4 52.4
Conversion of 950F+
26 on Fresh Feed, LV% -- -- -- 58.1
27 Operating Conditions
28 Temperature, F 824
29 Space velocity, v/h/v 3.2
Pressure, psi 200
31 (1) CCR denotes Conradson carbon residue
32 (2) NI denotes naphtha insolubles
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1 Example 2
2 To demonstrate the effect of recycling
3 hydrorefined bottoms on visbreaking performance, the
4 visbreaking step was operated at different severities
with and without recycle. The results of these tests
6 were summarized in the graphs of figures 3 and 4.
7 Figure 3 shows toluene insolubles in total visbroken
8 product versus reduction of 510C+ (950F+) yield with
9 and without recycle. Toluene insolubles are indications
of coke forming tendency. As shown in figure 3, recycle
11 of hydrorefined bottoms produced less toluene insol-
12 ubles at a given bottoms reduction or achieved higher
13 bottoms reduction at a given toluene insolubles. Figure
14 4 shows toluene insolubles versus conversion of 510C+
(950F+) as expressed on fresh feed. Under operable
16 conditions, visbreaking without recycle converted only
17 35% of the 510C+ in fresh feed, whereas with recycle,
18 about 60% of the 510C+ materials were converted while
19 toluene insolubles remained low (about 0.1 wt.%).
