NL8204949A - PROCESS FOR HYDRODE METALLIZATION OF A LIQUID HYDROCARBON FEED. - Google Patents

Description

Λ “- · Ν.0. 31548 1

Process for hydrodemetallizing a liquid hydrocarbon feed.

The present invention relates to the catalytic hydro-metallization of hydrocarbon oils, in particular liquid petroleum residues or slate oils, containing significant amounts of dissolved metals and sulfur.

The atmospheric or vacuum distillation of crude oil gives a residue (bottoms) containing significant amounts of asphaltenes and other hydrocarbons boiling above about 315 ° C, sulfur and dissolved metal impurities. Similarly, slate oil contains high-boiling hydrocarbons and often significant levels of dissolved metal. It is important to further process the hydrocarbon content of the residue to convert its high-boiling components to commercially attractive lower-boiling hydrocarbon products. Slate oil is also further processed to maximize its yield of desired low boiling products. U.S. Pat. No. 3,558,474 describes a process in which vanadium sulfide is suspended in a heavy residue and heated in the presence of hydrogen. In this process, the catalyst accomplishes three reactions: first, it reacts with or physically absorbs metals and other impurities, second, it catalyzes the conversion of sulfur to hydrogen sulfide, and third, it influences the desired conversions of hydrocarbon.

However, this one-step process has a serious flaw. The metal impurities tend to deactivate the catalyst activity for the other two reactions, and the sulfur impurities tend to deactivate the catalyst activity for the hydrocarbon conversion reactions. To compensate for this, one has to increase the reaction temperatures, which leads to yield losses or to use large excess of relatively expensive catalyst.

It has been recognized that it is advantageous to perform these reactions separately. 30 In the article by Hastings et al. "Demetallization Cuts

Desulfuration Costs, "The Oil and Gas Journal, June 30, 1975, pages 122-130, has been reported to obtain better results when using a three-stage process including metallization followed by desulfurization and then hydrocarbon conversion. A similar teaching can be found in U.S. Pat. No. 3,7676,569, while U.S. Pat. No. 3,972,259 describes the simultaneous demetallization and desulfurization of residues 8204949 + 2 and a circulating loop process in U.S. Pat. No. 3,841,996. for the catalytic hydrodesulfurization and hydrocracking of a residue Although US Pat. No. 3,841,996 suggests the use of a pretreatment for metal removal, this pretreatment is optional in such a way that demetallization can be accomplished if desired the circulating loop reaction system U.S. Patent 3,975 .259 and U.S. Patent 4,214,997 are of interest because of their teaching of using catalyst particle suspensions; especially suspensions of colloidal catalyst particles, to carry out various hydroprocessing reactions. Of course, these colloidal particles will be very difficult to remove from the reaction product.

In a purification reaction such as hydrodemetallization, there are particular advantages regarding a discontinuous process or a fixed bed plug flow process. In both of these processes, the product discharged is the most completely purified product in the reaction zone. In a stirred continuous reaction zone with back-mixing, the effluent is only an "average" equilibrium product of 20 newly added contaminated feed with the purified reaction product. This is, of course, less than ideal in the current situations, where unreturned metal can deactivate catalysts for desulfurization reaction and / or the hydrocarbon conversion reaction. The discontinuous mode is not realistic for use with the throughputs required in industrial scale refining. Similarly, plug flow through solid catalyst beds is not efficient for use in the treatment of impure residues since the leading edge of the beds tends to clog quickly with metals, sulfur, coke, salts and the like solids found in or formed from these distillation bottoms.

It is an object of the present invention to provide an improvement in the catalytic hydrodemetallization process for metal contaminated petroleum feeds, including petroleum residues and slate oils, which is effective in (a) removing metals to low levels, (b) allowing continuous operation and (c) allowing simple separation of the demetallized product from the demetallization catalyst.

According to the present invention there is provided a process 40 for catalytic hydrodemetallization of a petroleum feed selected from lelestone oils and residues containing a substantial amount of products boiling above 315 ° C, which are 0.5 to 10 wt% organic sulfur and containing 20 to 2000 parts by weight per million metals *. This method involves mixing the feed with gaseous hydrogen in an amount at least greater than the saturation and a solid demetallization catalyst of microporous nature and having a uniform particle size of 0.05-0.4 mm to form of a three-phase probe, passing the slurry in a stirred plug stream through a long tubular reaction zone sized to provide a slurry rate in the range of 30 to 450 cm / sec suitable to maintain the solid catalyst particles in slurry and provide an average residence time of the slurry in the reaction zone of 1.5 to 15 minutes at a temperature of 400 to 485 ° C and separating the effluent from this reaction zone into a solid catalyst-containing phase and a solid catalyst-free demetallized product phase.

In the process of the present invention, the metal content of the feed is reduced by a factor of at least 5 from the original value of 20 to 2000 parts by weight to 0 to 40 parts by weight per million.

The present invention will be further described with reference to the accompanying Figures in which: Figure 1 is a graphical representation of the activity of two dehydrodemetallation catalysts as a function of time, Figure 2 is a flow flag of a hydrodemetallization process of the present invention, and Figure 3 is a partial cutaway side view of a replacement reactor configuration for use in the method of the present invention.

30 Hydrocarbon supplies

Hydrocarbon feeds, efficiently treated according to the method of the present invention, contain significant amounts of metal, such as 20 to 2000 parts by weight per million of metal; preferably 75 to 1500 parts by weight per million and more preferably 100 to 1000 parts by weight per 35 million metal. These metals are generally present as organometallic compounds soluble in hydrocarbon feed. The metals present are generally mainly nickel and vanadium, but may also contain iron, copper and, for example, arsenic. The amounts and ratios of the metals present will vary depending on the nature of the hydrocarbon feed. When feeding a petroleum residue 8204949

«I

4, it will contain nickel and vanadium as the major metal impurities and these products will be present in amounts from 50 to 2000 parts by weight per million or more, usually from 70 to 1500 parts by weight per million. When the feed is a slate oil, arsenic is the most common impurity and is present in amounts from 20 to about 200 parts per million and more usually from 20 to 150 parts per million.

In the primary embodiment, the feed used is an atmospheric or vacuum petroleum residue, that is, the bottoms of atmospheric or vacuum distillation of a crude petroleum. Such products are characterized by the presence of a significant amount of products boiling above 315 ° C and significant amounts (e.g., 0.5 to 10% by weight) of organic sulfur. These petroleum residues used as feeds may optionally have undergone preliminary processing, such as washing to remove salts.

The residue feeds may have been subjected to a prior deasphalting treatment. Without such treatment, they can contain more than 50% by volume of asphaltenes.

When the feeds have been subjected to a prior deasphalting treatment, eg solvent deasphalting, such as deasphalting with propane, their asphaltic content will generally be reduced to substantially less than 10% by volume, often substantially 0%. Deasphalting will not lower the metal contamination level in the deasphalted oil at appropriate levels.

Examples of suitable feeds include the 315 ° C + residues and slate oils listed in Table A. Table A also lists representative metal contents generally observed with the feed products.

8204949 a * 5

TABLE A

Supply and density, ° API Metal content wt.

Nickel plus Vanadium Other c Vac. heavy Arab crude oil residue »4.6 ° 220

Vac. Venezuelan crude oil residue »10.9 666

Vac. residue of Callornian crude, 5.4 ° 294 yg q Vac. residue from Iranian crude oil, 6.3 ° 462

Atmospheric residue of Iranian heavy crude oil, 14.4 * 224

Atmospheric residue of Arabian heavy crude oil, 11.5 ° 124 25 Slate oil I, 18.8-19.7 ° 28 arsenic

Slate oil II, 20.2 ° 33 arsenic

Catalyst used

The catalyst used in this hydrodemetallization reaction is a solid particulate product. The particle size should be uniform within the range of about 0.05-0.3mm, that is, the catalyst particles will pass uniformly through a 0.3mm screen and retained on a 0.05mm screen. Preferably, the particles are uniform in the range of 0.06 - 0.21 mm and most preferably 22 in size 0.075 - 0.15 mm. The catalyst particles within this range offer advantages of being small enough to be suspended and formed into suspensions in the hydrocarbon feed to be treated, while being large enough to be fully recoverable from the treated product according to conventional centrifugation, filter 2q ring or like extraction processes. In addition, this particle size offers advantages of inexpensive formation by spray drying techniques, of the presence of high surface area to mass ratios, and of allowing very high metal absorption levels. Levels from 50 to 150% of the original catalyst weight can be observed. In addition, the catalyst particles of this size have been found to be more efficient in the useful use of hydrogen than the larger particles required in fixed bed metallization systems.

The uniform sized particles are preferably microporous.

With larger particles, such as, for example, granules of 1.2 - 4.75 mm, 8204949 6 there is often a need for a macroporous structure, which is not required here. Advantageously, the catalyst has an internal surface area of at least 100 m 2 / g, preferably 200-1500 m 2 / g, and more preferably 300-1200 m 2 / g.

Two general groups of catalysts are suitably used. The first group consists of supported non-noble heavy metal supported metal sorption catalysts consisting of an inert support, such as an inorganic oxide-like or siliceous support or activated charcoal or the like, on the surface of which the desired metals are deposited. Such carriers include, for example, alumina, silica-alumina, silica-magnesium oxide, silica, boron oxide, titanium oxide, zirconia and activated carbon. The metals used are metals of groups VI and VIII of the periodic table of elements and include nickel, tungsten, molybdenum, cobalt and the like and mixtures thereof. Iron and vanadium are also suitable metals. The metals are generally present as oxides or sulfides. Conventionally known supported hydroprocessing catalysts such as NiMo, NiW, CoMo or CoW on alumina or silica-alumina or activated charcoal can be used. Other examples of supported metal catalysts include NiFe, NiCo and NiV. The amount of metal present on the catalyst need not be large. Metal loads of 1% or less based on the total catalyst weight give good results. While a wider range of 25 loads, for example, loads of up to 10 or 15 wt% or more can be used and are within the scope of the present invention, their use is not considered advantageous and there are actually drawbacks of higher cost and lower final metallization capacity.

The second type of catalyst suitable in the present process are high surface area non-metallic sorption catalysts. Very simply, these catalysts are the aforementioned carriers without any metal being intentionally deposited on their surface. These materials are effective for the demetallizing ring reaction. Although not understood with certainty, these materials are believed to operate in a self-catalysis process. They initially exhibit their low demetallization activity, but after they have absorbed small amounts of metal, their activity increases. This relationship between the catalyst activity and time is shown graphically 40 in Figure 1, in which the degree of metal absorption from a metal feed 8204949 (7 language) is plotted as a function of time for two catalysts. The first catalyst, Catalyst A , is a supported metal-containing catalyst As it appears, it has a high initial activity, which gradually decreases with use, poisoning and loading of metal from the feed The second catalyst, Catalyst B, is a metal-free catalyst It has a lower initial activity, which increases with the deposition of metal.Once a substantial load (eg 1%) is reached, this material begins to act as a preloaded catalyst and allows a gradual decrease in activity see with continued use.

Preferred catalysts for use in the present invention are the activated charcoal, alumina, or alumina-silica based microporous catalysts with or without added metals. Most preferred are catalysts based on activated charcoal. Activated charcoal has significant cost benefits. The product itself is cheap and shows a cheap extraction of metals from it by ignition. Particularly preferred catalysts include activated charcoal without added metal and activated charcoal, which carries up to 1% by weight of CoMo, CoW, NiW, NiMo or NiV.

The Process Flow and Process Equipment The flow diagram for the process of the present invention is shown in Fig. 2, wherein a hydrocarbon feed, here, for example, an Arabian heavy roll of fluid containing 250 ppm of metals and 5 wt% sulfur, optionally desalted and / or deasphalted, is supplied to the hydrodemetallization unit through supply line 11 and supply pump 12. Particulate fresh catalyst is added to the ole feed stream through line 14. The catalyst is an activated charcoal of 0.075-0.15 mm with an average pore diameter of about 4 nm and a specific surface area of 500-750 m2 / g. The make-up catalyst is added in the amount of about 445 to 8900 and preferably about 890 to about 4450 and most preferably about 1780 cm 2 / hl oil feed. The solid catalyst is fed through the catalyst hopper 15 and 16, one of which is inoperative and filled through the catalyst feed line 17, while the other feeds line 14. The hopper is in use at elevated pressure so that the feed is not blown back into it.

This pressure is efficiently provided by hydrogen, which is transferred from the hydrogen supply line 19 through the pressure line 20 for the catalyst hopper. The resulting oil catalyst slurry passes through line 21, is mixed with about 2/3 liters per liter of recirculation catalyst slurry fed through line 41 to form a usually two-phase reactor feed slurry itself composed of about 1 / 8 to 1/2 and especially 1/6 to 2/5 and preferably about 1/3 parts by volume of solid catalyst and the remainder of liquid oil. This is equal to solid to liquid feed volume ratios of 1: 7 to 1: 1, especially 1: 5 to 2: 3, and preferably about 1: 2. This mixture is pumped through the slurry pump 22, mixed with additional hydrogen (to a total amount of hydrogen added from about 4450 to 26700 and especially about 8900 NnrVhl oil supply) fed through line 19 to obtain the required three phase solid-liquid gas slurry and heated at about 400 to 485 ° C, preferably about 425 to 485 ° C and more preferably at about 440 ° C in the feed heater 24. The heated mixture is continuously fed to the long tubular reactor 25 via conduit 26 at a pressure of from about 7000 to 19250 kPa and preferably from 10500 to 17500 kPa. The length of the reactor 25 is adjusted to provide an average suspension residence time of about 1.5 to about 15 minutes, preferably about 2.5 to 10 minutes. The diameter of the tubes in reactor 25 is adjusted to provide a medium linear suspension rate of 30 to 450 cm per second and preferably 60 to 300 cm per second. Such rates are high enough to minimize particle distillation, but low enough to minimize erosion of the reactor wall and degradation of the catalyst particle to fines. The metals in the feed are absorbed on the catalyst in reactor 25. As shown in Fig. 3, the reactor 25 may contain various static or active mixers to promote the dispersion of the catalyst and the solution of hydrogen in the oil feed. The dematerialized product is transferred from the reactor 25 via line 26 to the expulsion pot 27, in which residual hydrogen is removed and discharged from the top via line 29. The amount of hydrogen remaining can be small, since the originally added amount is generally controlled to significantly exceed the need. This is done for two reasons.

Firstly to minimize losses and secondly to ensure maximum liquid filling in the reactors. The excess hydrogen-40 substance can be discarded, but is preferably recycled or 8204949-9 used in further processing. The expulsion pot bottom product, a slurry consisting of demetallated oil and catalyst, is passed through line 30 to the catalyst separation hydrocydone 31. In the hydrocyclone 31, a light phase consisting of oil and 5 to about 100 parts per million catalyst is discharged cust. line 32 to filter 34, where the residual catalyst is separated leaving a substantially catalyst-free demethylated (usually less than 20 ppm metal) oil product filtrate which is withdrawn through line 35, usually for further hydroprocessing, such as hydrodesulfurization or hydroconversion as known in the art. * The heavy product formed in the hydrocyclone 31 is a catalyst-enriched product which is withdrawn through line 36 and fed to the secondary hydrocyclone 37. In the hydrocyclone 37 it is catalyst-enriched product separated into a hydrocarbon-rich fraction, which is recirculated to line 26 through line 39 and a concentrated catalyst fraction which is discharged from line 41 and recirculated to line 21. Part of the concentrated catalyst fraction is removed from line 41 through line 42, combined with the catalyst recovered in filter 34, fed through line 44, and passed to the decanter boiler 45, where about 445 to about 8900 cc of catalyst per hl of oil feed through conduit 46 is removed, optionally for disposal, but preferably for recovery of its metal content by devices not shown. The liquid phase obtained in decanter boiler 45 is recirculated to supply pipe 11 cust pipe 47 and recirculation pump 49. Those skilled in the art will recognize that the catalyst particle size of 50-300 mesh allows for more efficient use of a range of other solid / liquid separators in the catalyst recovery schemes, including simple filters, sedimentation devices, and the like. These can be replaced without departing from the scope of the present invention. Similarly, when other metal contaminated feeds are supplied, appropriate changes will be made to the operating conditions. For example, when slate oil containing 20 to 100 ppm of arsenic 35 is supplied, the reaction temperature is in the range of 400 to 485 ° C, but pressures of 700 to 14000 kPa will preferably be used and residence times of 1.5 to 5 minutes will be preferred.

Fig. 3 represents a reactor configuration, which is an alternative to the configuration shown in FIG. 2.

8204949 10

Reactor 50 of Figure 3 could be included in the process of Figure 2 as a replacement for reactor 25. Reactor 50 receives via line 51 a slurry of a metal-containing hydrocarbon oil feed, catalyst and hydrogen. The catalyst to oil ratio is as described above, the hydrogen to oil ratio is lower. The slurry is passed through long reaction tubes 52, 52a, 52b, etc., which tubes are sized to provide the rates and residence times set forth in the description of Figure 2. An internal mixer 54 is shown in tube 52b. It is mounted in such a way that its periodic replacement is possible when it begins to fill up and limits slurry flow. The tubes 52, etc. are horizontal. In Fig. 2, a vertical tube orientation was shown. Each will work, although there may be a preference for the horizontal tube placement as it maximizes the liquid filling level of the reactor and minimizes gas spaces. Another aid in the prevention of gas spaces can be the use of cascading hydrogen addition, as shown by the hydrogen inlets 55 and 55a, which are fed through the hydrogen line 56. A stepwise addition of hydrogen can allow the desired saturation of the liquid with hydrogen through the reactor without adding large excesses in previous reaction steps. The total hydrogen to oil supply is similar to that described in Figure 2.

8204949

Claims (14)

Process for the hydrodemetallation of a liquid hydrocarbon feed containing 20 to 2000 parts by weight per million dissolved metals, characterized in that the feed is mixed with gaseous hydrogen in an amount greater than the saturation and a solid demetallization catalyst, of a microporous nature and with a particle size of 0.05-0.3 mm to form a three-phase suspension, b. this slurry passes through a long tubular reaction zone, which is adapted to a slurry speed of 30 to 450 cm / sec and an average residence time of the slurry in the reaction zone of 1.5 to 10 minutes at a temperature of 400 to 485 ° C wherein at least a portion of the metals are deposited on the solid demetallization catalyst to form a demetallized hydrocarbon slurry and c. removing the demetallized hydrocarbon slurry from the slurry reaction zone and recovering a demetallized hydrocarbon free from demetallization catalyst from the demetallized hydrocarbon slurry. 2. Process according to claim 1, characterized in that the solid catalyst is made to be present in a volume ratio to the hydrocarbon feed from 1: 1 to 1: 7. 3. Process according to claim 1 or 2, characterized in that the passage through a long tubular reactor is carried out at a hydrogen pressure of 7000 to 19250 kPa. Process according to Claims 1 to 3, characterized in that a petroleum residue is used as the hydrocarbon feed, the metals consisting of nickel and vanadium. 5. Process according to claims 1 to 4, characterized in that a horizontal reaction zone is used as reaction zone. Process according to claims 1 to 5, characterized in that a solid demetallization catalyst is used, which contains inorganic or oxide-like or silicon-containing products or activated carbon with a specific surface area of at least 100 ml / g. Process according to claim 6, characterized in that a catalyst is used which also contains a non-precious metal Process according to claim 6 or 7, characterized in that a catalyst consisting of activated charcoal is used. 9. Process according to claims 6 to 8, characterized in that a catalyst is used which contains one or more metals, selected from 8204949 nickel, vanadium, cobalt and tungsten. 10. Process according to claim 8, characterized in that a catalyst is used which mainly consists of activated charcoal. Process according to claim 9 or 10, characterized in that a petroleum residue is used as a liquid hydrocarbon feed. 12. Process according to claims 1 to 11, characterized in that a hydrogen pressure of 10500 to 17500 kPa, a temperature of 425 to 485 ° C, an average residence time of 2.5 to 10 minutes and a suspension speed of 60 to 300 cm / sec. applies. Method according to claim 9 or 10, that a slate oil is used as a liquid hydrocarbon feed. Process according to claim 13, characterized in that a hydrogen pressure of 7000 to 14000 kPa, a temperature of 425 to 485 ° C, an average residence time of 1.5 to 5 minutes and a suspension speed of 60 to 300 cm / sec. applies 8204949