CA1076983A - Upgrading of heavy hydrocarbon oils - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A heavy hydrocarbon crude oil is upgraded by treatment in a suspensoid heat soaking zone in the presence of inert solids and a hydrogen and carbon monoxide-containing gas. The carbonaceous residue which is formed during the heat soaking and which deposits on the solids is converted to a hydrogen and carbon monoxide-containing gas, a portion of which gas is recycled to the heat soaking zone.

Description

BACKGROUN~ OF THE INVENTION
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2 1. Field of the Invention

3 This invention relates to a suspensoid heat soaking

4 process for upgrading heavy mineral oils. More particularly, the invention relates to an integrated heat soaking and 6 gasification process.
7 2. Description of the Prior Art 8 Heavy hydrocarbonaceous crude oils such as Cold 9 Lake crude and Athabasca bitumen have very high viscosities.
To transport the heavy crude oils to established refineries 11 by conventional pipelines and to refine the heavy crude oils 12 by conventional methods, the heavy crude oils must be treated 13 to match the viscosity and fractional distribution of commer-14 cial crude oils.
lS A process has now been found in which the heavy crude 16 oil is treated in liquid phase in a suspensoid heat soaking 17 zone in the presence of solid contact particles and a hydrogen 18 and carbon monoxide-containing gas. The treating gas may be 19 produced by gasification of carbonaceous material which is formed during the heat soaking stage.
21 By the term "suspensoid" is intended herein a zone 22 in which the contact particles are suspenaed in the oil. The 23 suspensoid operation has been used heretofore for catalytic 24 cracking a variety of hydrocarbon feedstocks in vapor phase and is described in Petroleum Refiner, October, 1947, pages 26 91-93 and Petroleum Refiner, November, 1950, pages 125-127 .
27 It is known to convert a heavy hydrocarbon oil to 28 lower boiling hydrocarbons by subjecting the heavy oil to 29 elevated temperature in the presence of a fluidized particulate contact material on which a carbonaceous deposit is formed by 31 the hydrocarbon undergoing conversion and in the presence of 32 a hydrogen-containing atmosphere produced by regeneration of '.j ~ 2 .
-- 10~7~983 1 the contact particles ~see, for example, u.S. patent 3,033,779 2 and U.S. patent 2,885,350).

4 In accordance with the invention, there is provided a p~ocess for upgxading a heavy mineral oil having a high 6 viscosity, which comprises: treating said oil at an elevated 7 temperature in the liquid phase in a heat soaking zone in the 8 presence of the hydrogen and carbon monoxide-containing gas 9 and solid contact particles maintained in suspension in said oil to produce a heat soaked hydrocarbon product of reduced 11 viscosity, and a solid carbonaceous material, at least a 12 portion of which solid carbonaceous material deposits on said 13 contact particles.
14 In accordance with one embodiment of the invention, a slurry of heat soaked hydrocarbon product and solid contact 16 particles with the carbonaceous deposition thereon is removed 17 from the heat soaking zone; the solid contact particles are 18 removed from the slurry, the separated contact particles with 19 a carbonaceous deposition thereon are treated in a reaction zone to convert at least a portion of the carbonaceous deposit to 21 a hydrogen and carbon monoxide-containing gas and at least 22 a portion of the hydrogen and carbon monoxide-containing gas 23 is recycled to the heat soaking zone.

Figure 1 is a schematic flow plan of one embodiment 26 of the invention.
27 Figure 2 is a ~raph showing the effect of temperature 28 on viscosity at various pressures.

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,Referring to Figure 1, a heavy mineral oil feed, such 31 as, for example, a heavy petroleum crude is introduced via 32 line 10 into a suspensoid heat soaking zone 12. Suitable 33 heavy mineral oil feeds for the process of the invention - 3 ~

10~9~3 1 include bitumens, tars, heavy crude oils and atmospheric 2 residua therefrom. The process is specially suitad to treat 3 immature type highly viscous crudes, that is, crudes that 4 have not been exposed to much maturation over geological time. Generally, these heavy mineral oils are very viscous, 6 that is, their viscosities range from about 10,000 to 200,000 7 SUS at 100F. because they contain a large amount of hydro-8 carbons having atmospheric pressure boiling points of 950F. , 9 for e~ample, about 50 weight percent or more of 950F. plus boiling materials. The total metal content (vanadium, nickel, 11 iron, etc.) of such feeds may range up to 2000 weight ppm and 12 higher. Generally these feeds have Conradson carbon contents 13 ranging between about 10 and 50 weight percent, and may contain 14 up to 8 weight percent sulfur.
Heat soaking zone 12 is operated at a temperature, 16 residence time and pressure chosen to give a desired pre-17 determined product viscosity, for example, to reach the 18 conventional pipeline viscosity of 180 SUS and/or a desired 19 fractional distribution. Suitable operating conditions include a temperature ranging from about 780 to about 810F., 21 a residence time ranging from about 20 to about 30 minutes 22 and a pressure ra~ging from about 800 to about 1000 pounds 23 per square inch gauge ~psig), such that the oil feed will be 24 predominantly in the liquid phase.
That a liquid phase operation would be suitable 26 for use 1n conjunction with a suspensoid system utilizing 27 accessible solids and synthesis gas is unexpected in view 28 of the prior art teaching that suspensoid catalytic cracking 25? should be conducted at conditions to permit complete vapor-ization of the hydrocarbon feed and of the more complex 31 systems utilized heretofore.
32 "Tube and tank" equipment is preferred because 33 witl~ the short residence time and the tube (preheat fu~nace) ~ ?:.J:~': !.." `
34 even with some 50 to 100F. higher temperature to compensate for tank hea~ demands, fouling of essential heat transfer 10'~9~3 .

1 surfaces could be avoided or minimized, and, because any 2 coke deposition that might occur at ultimate viscosity 3 due to some malfunction would not be critical. This does 4 not exclude use of tube only equipment where the needed larger low heat density furnace might direct attention 6 to shorter 15 minutes residence at higher 830-840F.
7 temperature and higher prQssures.
8 Solids are introduced via line 14 into heat 9 soaking ~one 12 as the contact particles. Suitable solids include a wide variety of materials and are generally 11 chosen from accessible by-products or waste material.
12 Inert (that is, non catalytic) solids are suitabla, for 13 example, sand fines, coal particles including those 14 resulting from cleaning operations, coke by-product gasifier or combustion ashes and other easily slurried 16 natural materials with some surface areaO Low surface area 17 materials, crystalline and abrasive solids such as coarse 18 sand and quartz are less preferred. Leach tailings from 19 leaching of ores are also suitable.Although the selected solids may have some catalytic properties, these properties 21 are only incidental and not required for the process of 22 the present invention.
23 The contact particles are introduced into the 24 heat soaking zone 12 in an amount sufficient to accept the amount of carbonaceous material or "coke" made at the 26 conditions required to meet the selected target. The 27 weight percent of contact particle is increased as the 28 Y~Scosity targets are lowered. By way of example, suitable 29 amounts of solid contact particles include from about 2 to about 10 p~unds of solids per barrel of oil feed to meet a 31 target of convention~ pipeline viscosity; however, the objec-32 tive is for low functionally adequate amounts to gain the .

0'7~

1 economics in equipment and operation.
2 The suspensoid heat soaking process can be conducted 3 in conventional thermal cracking equipment. It is conducted 4 at moderate pressures with low treat gas rate and low once-through added solids and thus does not require the special 6 equipment needed in fluidized bed or ebullating bed type 7 operations. The low synthesis gas treat rate and the suspen-8 soid process of the invention effectively reduces coke make.
9 It not only aids in keeping the solids suspended in the reactor system but assists a once-through movement (which is 11 another difference from fluidized or ebullating bed system).
12 Furthermore, the simultaneous occurrence of ~he water gas 13 shift reaction not only makes in situ hydrogen bu also 14 supplies some in situ heat since it is an exothermic reaction.
Contact of the oil feed with the solids and the 16 hydrogen and carbon oxide-containing gas under the given 17 opera~ing conditions produces a heavy carbonaceous material 18 tcoke)~ at least a portion of which deposits on the solids 19 present in the heat soaking zone. Generally, the oil feed remains in the heat soaking zone for a time sufficient to 21 match a selected target of viscosity or fractional distri-22 bution.
23 Suitable residence time in the heat soaking zone 24 in the 800F. temperature ranges broadly from about 20 minutes to about 30 minutes. A slurry of heat soaked oil 26 product and solids with a coke deposition thereon is removed 27 from heat soaking zone 12 and passed to a separation zone 18 28 wherein the solids are separated from the oil by conventional 29 means such as by settling or by use of liquid-solid cyclones or by centrifuges. The heat soaked oil is removed from 31 separation zone 18 via line 20. The heat soaked product 32 will have a viscosity at 100F. ranging from the selected . ...

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~ 10~7~ 3 1 minimum target of 180 sus to about 50 sus. since the heaviest 2 commercial crude curxently delivered, as is, by pipeline in 3 Canada has the 180 SUS viscosi~y at 100F., this was chosen 4 as the minimum target. A lower target is selected in order to match fractional distribution of alternate crudes and/or 6 to provide for direct fluxing. If desired, a portion of the 7 heat soaked oil product withdrawn via line 22 may be mixed 8 with the solids of line 14 as medium for slurrying the solids 9 ~nto heat soaking zone 12. The remainder of the heat fioaked oil product, which if desired, may be subjected to a conven-11 tional atmospheric or flash distillation process t~wer to 12 separate overhead a product having an end boiling point of 13 about 550F. to provide for direct fluxing of the virgin 14 crude and a bottoms heat soaked product at pipeline viscosity, that is, having a viscosity of about 180 SUS at 100F. By 16 direct fluxing of the virgin crude, a significant proportion 17 thereof need not be processed on site, and the natural 18 naphthenic characteristics are therefore preserved for 19 desixable alternative upgrading.
A stream of coked solids ~solids with a coke depo-21 sition thereon) is removed via line 24 and passed to zone 26 22 in which the coke deposition is converted to a crude hydrogen 23 and carbon monoxide-containing gas by conventional partial 24 oxidation or by conventional gasification wherein the coke is reacted with an oxygen-containing gas su~h as air or commer,cia' 26 oxygen introduced via line 28 and steam via line 30. The 27 crude gaseous product generally contains unconverted steam 28 and gaseous sulfur compounds. A typical partial oxidation ._ .
29 process is de~cribed in U.S. patent 3,7Z3,345, for example, 31 partial oxidation zone may be operated at the temperature in 32 the range between 2000 and 3000F. while employing pressures 10'7~
1 between 40 and 1500 psig at a suitable residence time. In 2 a typical gasification process, the coke deposition is 3 converted to carbon monoxide and hydrogen with by-products 4 such as carbon dioxide and steam and hydrogen sulfide. The gasification reaction may be any conventional gasification 6 reaction such as described in U.S. patent 2,582,938.

8 The crude gas product is removed from æone 26 via g line 32. Usually the crude gas is cooled to remove water and any liquid by-product before gas purification. Tha 11 crude gas is passed via line 32 to a gas cleaning operation 12 indicated at 34. In the gas clean.ing stage, gaseous sulfur 13 compounds and, if desired, C02 are removed from the gas to 14 produce a gas containing predominately hydrogen and carbon monoxide (synthesis gas) as reactive components. The purified 16 gas is removed via line 36. A portion of this gas is passed 17 via lines 37 and 38 into line 16 for introduction into heat 18 soaking stage 12. The remaining portion of the purified gas 19 removed via line 36 may be used as clean fuel or for synthesis of chemical raw materials such as methanol, ammonia and hydro-21 carbons according to normal processes. The following example 22 is presented to.illustrate the ~nvention.

24 Experiments were conducted in which a heavy crude ~Cold Lake crude, as produced, which contains about 2 wt.%

26 water~as~t oaked in a simulated suspensoid system with the 27 addition ~E different types of solids and in a synthesis 28 gas atmosphere utilizing 425 standard cubic feet of 29 synthesis gas per barrel of cr~de, to produce a crude 30 oil that would match commercial crude oils in viscosity 31 and fractional distribution. The experiments were conducted 32 in an autoclave reactor. The total liquid-slurry products 33 were removed from the autoclave through its 1/8 lnch diameter - 1~7~i9~

1 discharge line by simple pressure. The liquid feed to the 2 autoclave comprise 90 wei~ht percent of Cold Lake crude 3 (10.9 API, 0,OOOSUS viscosity at 100F., and had 56.9 4 weight percentOg2soF. plus fraction) and 10 weight percent e; of previously obtained centrifuged liquid product as 6 slurry medium for the selected solids which amoun~ed t~
' 7 5 weight percent of the crude or 4.5 weight percent of the 8 total liquid feed. The suspensoid system was simulated I 9 by first slurrying the solids in the slurry medium in the ¦ 10 autoclave. The crude was then added t~ the slurry with 11 mixing. The closed autoclave was pressured to 250 psig 12 with the synthesis gas atmosphere equivalent to 425 SCF/bbl.
13 Equ~l volumes of hydrogen and carbon monoxide represented 14 the product of a partial oxidization process based on oxygen, whereas a 16 volume percent H2, 23 volume percent CO, 61 16 volume percent N2 composition represented one based on air.
17 The stirring autoclave was electrically heated to reaction 18 temperature, held at that temperature for 20 minutes and 19 rapidly cooled using internal cooling coils.
The product gas was recovered and analyzed. The 21 easy removal of the total liq~id-slurry product from the 22 autoclave through its small 1/8 inch inside diameter discharge 23 line by simple pressure and the essentially clean reactor 24 surfaces (or even the easily cleaned surfaces at severe conditions) demonstrated the effectiveness of the suspensoid 26 system. The total product was centrifuged, the liquid 27 inspected and the separated solid analyzed after toluene 28 washing and drying.
29 The operating conditions and resulting products are summarized in the following table.

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1 In a xun without solids and with nitrogen atmosphere 2 at 783F. for 30 minutes residence, the liquid product 3 viscosity of 159 SUS at 100F. not only did not get to the 4 desired targetbut contained 3.8 weight percent of suspended benzene insoluble material and much carbonaceous material 6 was deposited on the autoclave internals. Excessively high - 7 coking in an impractical system was indicated for such an 8 operation at target viscosity of the tabled experiments.
9 In runs A, B, and C, in which heat soaked product was used as slurrying medium, the coke formation remained 11 low in spite of the residuum and asphaltene content of the 12 heat soaked product. The synthesis gas atmosphere used in 13 runs A, B and C represent products of partial oxidation with 14 oxygen or air and were used in low volumes and at relatively low pressures (800-1000 psig). The effectiveness of the 16 hydrogen and carbon monoxide-containing gas is shown by the 17 fact that the coke make remained low (0.85 weight percent).
18 The simultaneous conversion of carbon monoxide to carbon 19 dioxide is believed to be due to a water gas shift reaction with its in situ hydrogen production. This not only 21 contributes to the effectiveness but also to system 22 ~implification by making a separate hydrogen generation and 23 purification step unnecessary.
24 The increased H2/CO ratio in the product gas whan Z5 coal is used as solids is also noteworthy.
26 ExAMPLE 2 27 To determine the effect of temperature, pressure 28 and residence time on viscosity, without regard to any 29 coking or benzene-insoluble formation that may occur, experiments were conducted at pressures of 200 and 800 psig 31 at various temperatures and residence times by heat soaking 32 Cold Lake crude in the absence of added solids. The ' '` 10~9~
1 results are summaried in Figure 2. As shown in the graph, 2 short residence times and low pressure of conventional 3 visbreaking operations were inadequate because of the 4 very high temperatures with the accompanying coke deposition to reach the desired 180 SUS pipeline viscosity.

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Claims (13)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for upgrading a heavy mineral oil having a high viscosity, which comprises: treating said oil at an elevated temperature in the liquid phase, in a heat soaking zone in the presence of a hydrogen and carbon monoxide-containing gas and solid contact particles maintained in suspension in said oil, to produce a heat soaked hydro-carbon product of reduced viscosity and a solid carbonaceous material, at least a portion of which solid carbonaceous material deposits on said contact particles.

2. The process of claim 1, which comprises the additional steps of (a) removing a slurry of heat soaked hydrocarbon product and solid contact particles with a carbonaceous deposition thereon from said heat soaking zone;
(b) separating the solid contact particles from the slurry of step (a);
(c) treating the separated contact particles with a carbonaceous deposition thereon in a reaction zone to convert at least a portion of the carbonaceous deposit to a hydrogen and carbon monoxide-containing gas; and (d) recycling at least a portion of the hydrogen and carbon monoxide-containing gas obtained in step (c) to said heat soaking zone.

3. The process of claim 1 wherein said heat soaking zone is maintained at a temperature ranging from about 780°F. to about 810°F. and at a pressure ranging from about 800 psig to about 1000 psig.

4. The process of claim 3 wherein the residence time of said oil in said heat soaking zone ranges from about 20 minutes to about 30 minutes.

5. The process of claim 1 wherein said contact particles are substantially inert particles.

6. The process of claim 1 wherein said contact particles comprise sand, coal, and coke.

7. The process of claim 2 wherein said reaction zone of step (c) is a partial oxidation zone.

8. The process of claim 2 wherein said reaction zone of step (c) is a gasification zone wherein the carbonaceous deposit is reacted with steam and an oxygen-containing gas.

9. The process of claim 2 wherein the hydrogen and carbon monoxide-containing gas resulting from step (c) is passed to a gas cleaning stage to reduce its sulfur content prior to said recycling step.

10. The process of claim 1 wherein a portion of said heat soaked hydrocarbon product is mixed with solid contact particles to form a slurry which is introduced into said heat soaking zone.

11. The process of claim 1 wherein said heavy mineral oil is a heavy petroleum crude oil.

12. The process of claim l wherein said heavy mineral oil is a tar sand oil.

13. The process of claim 1 wherein said heavy mineral oil has a viscosity ranging from about 10,000 to about 200,000 SUS at 100°F.