DE2103027C3 - Process for refining a hydrocarbon material containing heptane-insoluble asphaltenes - Google Patents

Description

Raw oils and especially extracted from tar sands Heavy oils, topped or reduced crude oils, and vacuum residues, all commonly known as black oils contain large amounts of high molecular weight sulfur compounds and also nitrogen compounds, high molecular weight organometallic complexes, mainly those of nickel and vanadium, and asphaltenes.

Such hydrocarbon materials have heretofore been obtained by liquid phase hydrogenation or vapor phase or Mixed phase hydrocracking refined. The former type of procedure leads to an effective conversion at least a portion of the oil-soluble metallurgical complexes, but is relatively ineffective with respect to the asphaltenes, which leads to their flocculation and agglomeration. The cracking process, on the other hand quickly lead to catalyst deactivation due to the deposition of coke and metal-containing impurities.

From US-PS 13 65 463 a process for hydrofining crude oils with the aid of Vanadine-containing catalysts known, as such vanadyl acetylacetonate or a colloidally distributed Vanadium sulfide can be used. The use of non-stoichiometric vanadium sulfides can be but not inferred from this publication.

The object on which the invention is based was now to provide a compared to the prior art Technique of a better method for refining a hydrocarbon material containing heptane-insoluble asphaltenes to get the better yields of a liquid hydrocarbon product and results in the least possible deposits in the reaction zone.

The inventive method for refining a heptane-insoluble asphaltenes-containing hydrocarbon material in a colloidal mixture with a carrier-free sulfur-vanadium caialyzer at a temperature of 325 to 500 ^c C, under a pressure of 69 to 273 at with hydrogen is characterized in that the catalyst used is non-stoichiometric vanadium sulfide with an atomic ratio of sulfur to vanadium in the range of 0.8: 1 to 1.8: 1

As hydrocarbon materials one can expediently those with specific gravity at 15.6 ° / Use 15.6 ° C greater than 0.934, of which a large one Part has a specific gravity greater than 1.0 and boils 10 • or more volume% above about 566 ° C.

H) A specific example of such materials is a Bottom product of a vacuum tower with a specific gravity of 1.021, containing 4.05 wt% sulfur and 23.7 wt% asphaltenes or a vacuum residue with a specific Weight of 1.009, containing 3.0% by weight of sulfur and 4.3 ppm of nitrogen, with 20.0% pass over at a distillation temperature of 568 ° C. In refining according to the invention converts insoluble asphaltenes into normally liquid products that boil lower and into hydrocarbons are soluble. Sulfur and nitrogen compounds are converted into hydrogen sulfide and ammonia convicted.

That in the inventively used carrier-free

2 ^r > catalyst present atomic ratio of sulfur to vanadium in the specified range can be based on the fact that a mixture of vanadium sulfides with different atomic ratios of sulfur to vanadium is present.

ίο Although four oxidation states are known for vanadium, only three stoichiometric vanadium sulfides are sufficiently stable, namely vanadium monosulfide VS, vanadium sesquisulfide V ₂ Sj and vanadium pentasulfide V2S5.

For the production of those used according to the invention

Jj nonstoichiometric Vanadinsulfide it is expedient first to prepare Vanadintetrasulfid by reducing vanadium pentoxide in sulfur dioxide and water, and the thus obtained solid Vanadylsulfattrihydrat with hydrogen sulfide at 250 to 350 ⁰ C, for example at 300 ⁰ C treated. This vanadium tetrasulfide is now preferably added to the hydrocarbon material to be refined in an amount of 1.5 to 25% by weight, calculated as elemental vanadium, in which the tetrasulfide is mixed with the hydrocarbon in the hydrocarbon

ii material stream contained hydrogen is reduced to non-stoichiometric vanadium sulfide. The vanadium tetrasulfide is expediently in finely divided form, such as with a particle size of 0.07 to 0.15 mm.
Although the vanadium tetrasulfide can also be reduced prior to slurrying in the hydrocarbon material, the method outlined herein is more convenient because the vanadium tetrasulfide is unstable above 100 ° C. and reduction is facilitated when slurried in the feedstock

■ »is available.

The charge of hydrocarbon material with catalyst suspended in it is mixed with the hydrogen in such a ratio that 1780 to 17,800 parts by volume of H ₂ per part by volume of the liquid

Mi feed material is available. The temperature of the The feed mixture is brought to the level desired at the inlet to the reaction zone. Since the in the reactions taking place in the reaction zone are mainly exothermic, is the outlet temperature

H. higher than the inlet temperature. If the inlet temperature is set in the range from 325 to 380 "C, the use in the reaction / one is chosen so that the outlet temperature is not higher than 500 ^c C. Good

Results are obtained when the temperature gradient is located at 380 and 450 ⁰ C. The reaction zone is preferably maintained at a pressure of from 103 to 273 atm.

An upflow system is particularly useful in the process according to the invention, since the extremely heavy portion of the feed material results in a longer residence time in the reaction zone, a higher degree of conversion is obtained and the hydrogen stripes lower-boiling products from the reaction mixture. Also, the heavily reacted asphaltene material can be withdrawn from the bottom of the reaction zone along with the solid vanadium sulfide particles. The liquid product effluent, which contains distillable hydrocarbons along with hydrogen, hydrogen sulfide, ammonia and a minor amount of normally gaseous hydrocarbons such as methane, ethane and propane, is removed from the top of the reaction zone. This product outlet can in a flash evaporation system, which operates at essentially the same pressure as the reaction zone in a first stage and at essentially reduced pressure in a second stage, in a vapor phase, of which the main part boils below 427 ° C, and a liquid , 2 ^r > phase boiling above 427 ° C can be separated. The latter can be recycled and combined with fresh feed to serve as a diluent for the feed, or it can be used to facilitate the introduction of fresh and / or regenerated catalyst into the reaction zone in admixture with the feed.

The mainly vapor phase is separated into a high pressure separator at a temperature of J5 16 to 49 ° C, in which a hydrogen-rich gas phase is separated off and returned to the refining process together with make-up hydrogen will. The normally liquid phase from the high pressure separator, which contains about butane, is subjected to fractionation to give a feed suitable for further treatment to get.

The bottom product of the flash system can be recycled in its entirety and combined with fresh hydrocarbon feed, but it is convenient to withdraw a sidestream containing at least about 10.0% by weight of the catalyst used. The catalyst can be separated from the liquid hydrocarbon phase by any conventional means such as filtration, settling tanks, or a variety of centrifuges. An equal amount of fresh or regenerated catalyst is then added to maintain the catalyst concentration in the slurry. The catalyst withdrawn with the sidestream is separated, for example, by several filtrations and washed with methylnaphthalene in order to remove residual soluble hydrocarbons from the catalyst sludge. Other solvents suitable for this purpose are, for example, n-heptane, benzene or toluene. The remainder of the catalyst slurry is heated in air to obtain vanadium pentoxide which is reduced again with sulfur dioxide and water to form vanadyl silfate. ι, ί

Comparative example 1
The hydrocarbon material used was a crude oil with the following properties:

Specific weight at 15.6 ° C 1.014

Average molecular weight 630

Heptane insolubles, wt% 16.8

Sulfur, wt% 6.4

Nitrogen, ppm 6585

Total amount of metals, ppm 1410

An Engler vacuum distillation showed an initial boiling point of 279 ° C and a distillation temperature for 30.0% by volume at 488 ° C, with 41.0% being distillable at about 566 ° C.

Stoichiometric VS was suspended in this crude, and thereafter the crude became in rising Treated mode of operation by 75 g / hour at a temperature increase from 370 to 440 ° C in a Reaction kettle were fed. The pressure was 205 atmospheres and the amount of hydrogen was 2680 parts by volume Gas per part by volume of liquid. The reaction kettle was made of ceramic material with a porcelain glaze Lined on a titanium base to reduce the amount of deposits on the inner walls to obtain.

The initial results were relatively good: 97.0% of the asphaltenes were converted, 98.0% of the metallic ones Impurities, 72.0% of the sulfur and 58.0% of the nitrogen were removed. After 28 hours However, the pressure in the reactor fell. After a further 30 hours a pressure difference made 17 atmospheres require an interruption of work. A contemplation of the inside of the reactor showed heavy precipitation on the walls and on the sieve near the top End of the kettle.

Comparative example 2

For this experiment, an aqueous solution of vanadyl sulfate mixed with the crude oil feed was fed into the reaction zone. The vanadyl sulfate solution had a specific gravity of 1.0528 at 15.6 ° C. and contained 1.66% by weight of vanadium. At the beginning of a temperature gradient from 275 to 420 ⁰ C, a pressure of 205 atmospheres, a hydrogen amount of 16 100 parts by volume of gas per volume liquid, a raw material feed rate of 150 g / hour and a catalyst solution feed rate of 50cm ^J / hour is set. After working for 22 hours, approximately 75.0% of the hcptane insolubles and 87% of the metals were converted. The specific gravity of the normally liquid product outlet had dropped to 0.966 from 1.014 of the fresh charge.

After about 35 hours of operation, a significant pressure drop was observed in the reaction zone and the introduction of the feed and catalyst solution was discontinued. After three hours, the hydrogen circulation feed was reintroduced at a rate of 75 g / hour and the temperature increased to 360-420 ⁰ C. After 167 hours of operation, analyzes of the normally liquid product leakage showed the following results:

specific weight
Heptane-insoluble components,
Wt%

Sulfur, wt%
Nitrogen, ppm
Total amount of metals, ppm

0.925

0.21
2.12
3720
9

Components that can be distilled,

97.5

Over the next 24 hours, the feedstock was poured onto a bottoms Relocated vacuum column with the following properties:

specific weight 1.001 Components that can be distilled, Vol.- ° / above 566 ° C 30.0 Deptane-insoluble components, Wt% 5.2 Sulfur, wt% 3.06 Nitrogen, ppm 4030 Total amount of metals, ppm 98

After 191 hours of operation, analyzes of the normally liquid product leak showed the following given values:

Specific gravity 0.937

Heptane-insoluble parts of the land,

Wt% 0.14

Sulfur, wt% 1.17

Nitrogen, ppm 3000

Total amount of metals, ppm 9

Components that can be distilled,

% By volume 90.5

The introduction of the feed material and the Catalyst solution was stopped, but hydrogen circulation got about further 42 hours continued. The heater and the hydrogen compressor were turned off, and the pressure relief started.

Toluene was fed in at a rate of 200 cm ³ per hour and a temperature of 150 ^{° C.} After 20 hours, followed for 18 hours supply of methylnaphthalene at 200 ⁰ C. toluene was further 6 hours at a temperature of 75 ° C injected. This procedure allowed the reaction zone to be completely depressurized, which when opened showed that it was completely packed with a solid material which could only be removed by drilling out. The recovered material was treated with methylnaphthalene to remove organic soluble matter, and then it was treated with pyridine. The individual washing liquids were precipitated with pentane, and the precipitate washed with pyridine was recovered in an amount of about 95 g. The solids did not contain sulfur but contained 8.1 wt% nitrogen and about 5.0 wt% vanadium.

The clogging of the reaction zone, as evidenced by the pressure difference, is mainly the Attributable to accumulation of unconverted heptane-insoluble asphaltenes in the zone. This is apparently a result of the phase separation that occurred during the decomposition of the vanadyl sulfate in the presence of the Asphalt materials occurs. This apparently creates an environment conducive to the formation of asphalt complexes is conducive to the reaction conditions used.

example

The feedstock used in this example was that described in Comparative Example 2 Bottom product of a vacuum column. Vanadium pentoxide was reduced to sulfur dioxide and water To produce vanadyl sulfate trihydrate. The latter was

κι in a hydrogen sulfide atmosphere at 300 ° C and the resulting vanadium tetrasulfide became 0.07 to 0.15 mm in particle size to marry. 832 g of the tetrasulfide became 1200 g of the Bottom product of the vacuum column in a colloid mill

| 5 added over about 4 hours. The reaction zone was preloaded with about 255 g of the mixture of oil and vanadium tetrasulfide and the plant was turned on pressurized to about 205 atmospheres. There were about 5350 parts by volume of hydrogen each

2 »Part by volume of liquid supplied.

The heating block was raised to 100 ⁰ C and held for one hour at this level, after which the Heizblocktemperalur was raised to 300 ⁰ C. At this point the bottom product of the vacuum column with the vanadium tetrasulfide mixed with the circulating hydrogen stream was introduced into the heater. The temperature gradient from the inlet of the reaction zone to the outlet thereof was adjusted to 320 to 385 ° C by adjusting the temperature of the oven shell of the heating block to about 410 ° C. The feed rate was 25 ml per hour and make-up hydrogen at about 135 liters per hour was added to the process.

The precursor compound of the unstoichiometric vanadium sulfides used according to the invention had when feeding into the reaction zone an atomic ratio of sulfur to vanadium of 4: 1 reducing conditions in the reaction zone

The vanadium tetrasulfide decomposed and surrendered non-stoichiometric vanadium sulfides of various compositions. One after an eight-hour reduction Sample taken of the precursor compound vanadium tetrasulfide showed an atomic ratio of sulfur to Vanadium of 1.45: 1, a sample taken after 28 hours an atomic ratio of 1.06: 1, and at That was the end of the experiment after 116 hours Atomic ratio at 1.32: 1.

A conversion of more than 99.0% of the heptane insolubles was obtained and the operation was terminated voluntarily after 116 hours without a noticeable pressure drop was observed in the reactor. After processing 1200 g of the bottom product of the vacuum column, analyzes showed about 0.03 wt.% asphaltenes in the product outlet, less as 5 ppm vanadium complexes (as elemental vanadium) and about 6 ppm nickel. The specific The weight of the normally liquid product had dropped to 0.956. The difference calculation with regard to the

Vanadium introduced as a catalyst showed very little loss due to deposits on the walls of the boiler.

Claims (2)

Patent claims: 1. A process for refining a heptane-insoluble asphaltenes-containing hydrocarbon material in a colloidal mixture with a carrier-free sulfur-vrnadine catalyst at a temperature of 325 to 500 ⁰ C, under a pressure of 69 to 273 atm with hydrogen, characterized in that the catalyst used is non-stoichiometric vanadium sulfide with an atomic ratio of sulfur to vanadium in the range of 0.8: 1 to 1.8: 1. 2. The method according to claim 1, characterized in that that the hydrocarbon material is obtained by reducing vanadium pentoxide in Sulfur dioxide and water and subsequent treatment with hydrogen sulfide at 250 to Vanadium tetrasulfide obtained at 350 ° C, preferably in an amount of 1.5 to 25% by weight, Calculated as elemental vanadium, admixes and the tetrasulfide with that in the hydrocarbon stream contained hydrogen is reduced to non-stoichiometric vanadium sulfide.