DE2259592A1 - PROCESS FOR HYDRATING DESULFURIZING ASPHALTIC OILS - Google Patents

Description

GULP EESBARCH & DEVELOPIiENT COMPAiIY Pittsburgh, Pennsylvania, V.St. A. "

Process for hydrated desulphurisation of asphaltic oils

For this application, priority will be given on December 8, 1971 from US patent application Serial Nq. 206 078 to claim

"■ taken. '".

The invention "relates to a process for the production of Raw or rucksack oils with a particularly low sulfur content. In particular, the invention relates to a process for hydrodesulphurisation for the production of asphalt ' • containing fuel oil with a low sulfur content.

■ There are different processes for hydrated desulphurisation known of petroleum-based substances, according to which sulfur is very effective in lighter distillate fractions can be withdrawn, which v / earth obtained by distillation of crude oil. Contain crude oil and topped crude oil fractions but a heavy residue fraction boiling above 560 ° C and commonly referred to as "asphalt". As a result ' the presence of this fraction makes the oil much more difficult desulfurize. Asphalt is generally an inferior material that is isolated from crude oil and used for road building is used. It is also known to convert asphaltic fractions of the crude oil into more valuable products, such as heating oil. However, if you isolate asphalt, it is extremely viscous and it is difficult to prepare for catalysts. Furthermore, asphalt consists of large molecules with condensed

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aromatic rings and contains the largest te sulfur content of the crude oil. Another problem is that some of the sulfur content of the asphalt is inside the large molecules is bound, v: as the desulfurization of the Aaphalts even more difficult. Asphalt also contains metals, mainly nickel and vanadium, which easily affect the Deposit desulphurisation catalysts and deactivate them. All of these circumstances act to remove the sulfur & us heavy, asphaltic oils in much harsher conditions in the form of higher temperatures and pressures as well as other catalysts are required than for the desulfurization of distillate oils. .

Sulfur is a major cause of air pollution. Therefore, some municipalities prescribe an upper limit for the sulfur content of heating oils. So far, such authorities have set an upper limit of ΐ percent by weight for heavy heating oils; The tendency, however, is to reduce the permissible maximum sulfur content even further, e.g. to 0.5 $ Such limits represent an obstacle to the use of heavy asphaltic coal fuel oil fractions as heating oil, because asphaltic heating oils with sulfur contents of 0.5 # from crude oils with so. high sulfur content cannot be easily produced by passing the crude oil over a desulfurization catalyst.

Up to now one was able to determine the sulfur content of a special asphaltic crude oil or topped up crude oil reduce hydrogenation desulfurization to 1 percent by weight; however, if the sulfur content is further reduced, should be, the desulfurization temperature had to be so high be increased that an excessive hydrogenative cleavage to lower-boiling products took place. Although it is relatively proportionate It was easy to determine the sulfur content of such residual oils without excessive decomposition of the starting material from 4 To reduce to 1 percent by weight, it is much more difficult with the Mohrzahl of the typical starting materials without them excessive hydrative cleavage to withdraw more than about 75% of their sulfur content. Cinema too strong hydrating cracks

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However, it is undesirable because it consumes hydrogen unnecessarily and to form undesirable lighter products as well leads to coconut deposits on the desulfurization catalyst. Furthermore, it can happen that this changes the type of dis-. changes standing products so far that you no longer get a heavy fuel oil; heavy oils are close! but generally have a higher calorific value than lighter oils.

Other methods that have been tried to extensively desolate such asphalt practices. mixing the asphaltene-containing oil with Kohlenwasserst off practically smoldering ¹ elfreien distillate oils and medium boiling, the hydrofining of oils asphaltenisehen under conditions, "are where the asphaltic material completely environmentally by hydrogenolysis to lower boiling hydrocarbons. is converted.

'. There is / is therefore a need for a method for desulfurizing asphalt-containing hydrocarbon oils in order to make them more suitable for use as heavy fuel oils without the need to mix them with lighter oils or to convert their asphalt content into lower-boiling products to convert completely different IT nature and to have to accept premature deactivation of the catalyst in the process. ". '- . <■'

It has now become a relatively simple method of controlling the hydrodesulfurization of asphaltic oils found in which the oil does not undergo excessive hydrogenative cleavage suffers, and that consists in the fact that you have a residual oil, which contains e.g. an asphaltic fraction, together with hydrogen passes through a hydrogen desulfurization zone. When passing through the hydrogen desulphurisation zone, the aromatic content of the oil increases due to the formation of hay Aromatics in the desulfurization zone. The asphaltic oil Substantially reduced sulfur content is withdrawn from the hydrodesulfurization zone at the point above that the aromatic content of the oil does not increase any further.

When the asphaltic oil passes through the zone of hydrating Desulfurization flows, aromatic fragments split

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of the asphaltic part of the oil from outer area of the intricately composed asphaltic Molecules. These aromatics act as solvents for the asphaltic material and enable it to be desulphurized without excessive other conversion. By the measure the control of the desulfurization process in such a way that the asphaltic oil in the presence of a progressively increasing weight percentage amount of aromatics or at least desulfurized under such conditions that the weight percentage The proportion of aromatics does not decrease, there will be excessive hydrogenative cleavage of the asphaltic fraction avoided, and the asphaltic fraction is desulphurized in the optimal way under the process conditions.

For example, a fuel oil containing an asphaltic fraction with a sulfur content of less than 1 percent by weight be prepared according to the invention by using an asphalt-containing or asphaltic hydrocarbon oil, such as a crude oil or a residual oil (a topped up crude oil) that contains greater than about 1 weight percent sulfur along with Hydrogen feeds to a zone of hydrating desulphurisation and from it a first discharge of reduced sulfur content deducts when "the aromatic content of the oil does not increase further · This process consists of hydrogen sulfide, a light gas fraction, an aromatic and saturated hydrocarbons containing oil fraction and a higher-boiling, asphaltic fraction. The oil fraction is contrasted here; to the higher-boiling asphaltic fraction called "light oil". The hydrogen sulfide, the light gas fraction and a low-boiling part of the light oil fraction are of the Drainage separated, and the rest of the drainage from the asphaltic Fraction and the higher-boiling part of the oil fraction can be combined with hydrogen in a second zone are fed to the hydrating desulphurisation. A catalyst is located in both zones of the hydrated desulphurisation for hydrogenative desulphurisation, which has a carrier without cracking activity. From the second zone of the hydrating Desulfurization becomes a heavy asphalt

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Subtracted heating oil that contains less than 1 percent by weight of sulfur contains. The sulfur content of the heavy fuel oil thus obtained can be to our 1 percent by weight, e.g. below 0.5 or even 0.3 percent by weight, be reduced.

The asphaltic hydrocarbon oil with a sulfur content of more than about 1 percent by weight obtained, for example, as the product from the first hydrodesulfurization zone can, together with hydrogen and a light oil fraction, the aromatic and saturated hydrocarbons with boiling points below the boiling range of the asphaltic part of the asphaltic hydrocarbon oils, one second zone of hydrated desulphurization are fed, whereby the amount of light oil present in this zone and consequently the amount of aromatic and saturated hydrocarbons fed to the hydrodesulphurisation zone controls so that the desulphurisation rate increases and recovering a heavy asphaltic fuel oil having a sulfur content of less than about 1 percent by weight.

According to the invention, therefore, one obtains an asphalt-containing heavy heating oil that is practically sulfur-free, without the asphalt-containing heating oil with a sulfur-free one To have to mix distillate oil of medium settlements in order to to obtain an oil of low sulfur content, although this Even within the scope of the invention, there is no measure of mixing is excluded.

The term "asphalt" or "asphaltic" includes those in Resins and asphaltenes contained in crude oil. The proportion of the isphalt in the crude oil can be approximately 5 to 30 percent by volume or more, and the asphalt has an initial boiling point of about 560 ° G. It is used in refineries by deasphalting with Propane (solvent extraction) or obtained from distillation residues. The asphaltenes are highly aromatic, consist of large molecules with condensed aromatic rings and have all of the constituents of all crude oil usually the highest concentration of sulfur. To the under-

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Unlike other crude oil fractions, asphalt also contains metals, mainly nickel and vanadium. The As-

Phaltenes and resins therefore differ from the rest of the crude oil, which consists of "saturated hydrocarbons" and "aromatics" ", in that the aromatics and saturated hydrocarbons are soluble in propane while the asphaltenes and resins are insoluble in propane. *

The propane-soluble "aromatics" include benzenes, naphthalenes, thiophenes, benzothiophenes and dibenzothiophenes as the main types of molecules, while among the "saturated: hydrocarbons" the non-aromatic ones, soluble in propane Hydrocarbons, such as naphthenes, e.g. cyclohexanes, and paraffins, e.g. dodecane, as well as sulfur compounds, such as butyl mercaptan. This is commonly referred to as "asphalt" The material is therefore the residue from the propane extraction. On the other hand, the resins and asphaltenes can be separated from each other separate by extraction with pentane, because the asphaltenes are insoluble in pentane, while the resins and oils are soluble in pentane. .

It is known to bring crude oil or topped crude oil, which contains the asphaltene fraction, to a lower sulfur content by means of hydrogenating desulphurisation. For this purpose, the crude oil or the topped off crude oil is passed together with hydrogen over metal catalysts of Group YI and Group VIII of the Periodic Table on a catalyst carrier without cracking activity, such as aluminum oxide, the sulfur content being relatively easy to reduce from 4 to about 1 percent by weight, which corresponds to a sulfur removal of 75 S ^. If a specific output product such as a Kuwaiti crude oil but 75 f * of its sulfur content are, first of all been withdrawn, the sulfur contained in the starting material that is suddenly very resistant Eiterer against further desulfurization, and a v / sulfur removal can only be under considerable achieve hydrative cleavage, so that a great deal of hydrogen is consumed and the nature of the product changes. The point at which the in the crude oil

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remaining sulfur resistant can vary depending on the type of crude oil. This point can easily be determined by experiment. As “already mentioned, the asphaltenes consist of large molecules with condensed aromatic rings and contain sulfur inside these large molecules, so that the sulfur is extremely difficult to remove from them. Furthermore, the asphalt contains all metals, such as nickel and vanadium, which are in the Crude oil occur, and these metals are easily deposited on the catalyst and make it less effective. Therefore, more severe conditions in the form of higher temperatures and pressures are required to remove more than $ 75 of its sulfur content from the asphaltic oil, and such severe conditions lead to cleavage by hydrogenation, that is to separation of the carbon-carbon bond of the asphalt molecules s, reducing the molecular weight of ^the:.. the product, but not to a desulfurization by cleavage of carbon-sulfur bonds' -_-- -

To further explain the invention, reference is made to the drawings. -'-

Fig. 1 is a flow diagram of the desulfurization of a asphaltic topped crude oil in two stages.

2 graphically shows the percentage yield of substances which boil above the start of boiling of the feed fed to the desulfurization reactor with increasing mean reactor temperature. .

Fig. 3 shows graphically the change in the concentration of aromatic, saturated, asphaltene and resin fractions of a sisphaltene-containing topped off crude oil with increasing Degree of desulfurization.

Fig. 4 shows graphically the percentages by volume of aromatics and saturated hydrocarbons, which in various Output temperatures between the process stages be aborted.

. Figures 5 through 9 are flow diagrams of methods of production a light, aromatic-rich fraction of low

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According to the sulfur content of a part of the starting material, in order to make the solution of the asphaltenes and resins in the residue part of the starting material more fluid before the asphaltenes and resins are desulfurized, * _:

Am topped off crude oil, like a 50 # topped off Kuwait crude oil, all of the asphalt of the original crude oil and therefore all of the nickel and vanadium as well as the Most of the consistent sulfur content of the original crude oil is fed through line 10 (Fig. 1) and through line 14 »preheater 16, line 18, solids liter 20 and line 22 conveyed into the drum 24. Ans the drum 24 passes the liquid oil through line 26 to Feed pump. 30.-

The liquid discharged by the pump 30 is carried along with it hydrogen supplied through line 32 is mixed and passed through line 341 to valve 36 and line 38 into furnace 40. The liquid valve 36 is located in a not completely preheated line for liquid hydrocarbons! Circulating hydrogen and (if applicable) make-up hydrogen are added to the liquid reactor charge before it is preheated added. The circulating hydrogen flows through Line 42 and * valve 44, during the make-up hydrogen through line 46, the compressor 48 and the valve 50 pull, can be set. Circulating hydrogen and make-up hydrogen are fed into the liquid feed which is relatively cool introduced through line 32.

Bas pre-heated mixture of liquid feed and Hydrogen in line 54 can optionally be a (not shown) protective reactor are supplied. About the outlet of the, protective reactor is fed into the main reactor 60, which contains the catalyst beds 62, 64 and 66 '. This stream can e.g. have a boiling range from 343 ° C upwards.

The catalyst used for hydrodesulphurisation is of a conventional type and contains, for example, metal Groups VI and VIII of the Periodic Table on one frager without cleavage activity. The catalyst can, for example, be made of nickel-carbon

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balt-Moiybden or cobalt-molybdenum on an alumina carrier. The alumina can be stabilized with 1 "to 5 weight percent silica. The preferred catalyst is a 'nickel-cobalt-molybdenum catalyst on alumina containing less than 1 weight percent silica, and can optionally be sulfided. Another carrier without Fissure activity is magnesia. A particularly preferred catalyst is described in U.S. Patent 3,562,800 and consists of! particles with diameters of about Q.64 to 1.5 Bm. The same catalytic converter can be used in all terrain stages or different catalysts can be used for the hydrogen desulfurization. -. ".- ■.

An essential feature of the invention is that that the catalyst has a "! rager without cleavage activity, because practically no cleavage takes place in the process and very little. Material with a lower boiling point than the beginning of the boiling point of the starting material should be generated · However, higher-boiling parts of the starting material are split to lower-boiling products, provided these are still in the boiling range of the starting material. In the * in contrast to known processes, in which e.g. Catalysts containing, for example, 1Gf # or more silicon dioxide for the hydrogenative cleavage of the asphaltenes of the original goods are used, it comes with the Process according to the invention mainly only for a separation of the carbon-sulfur bonds of the Asphältene and Resins, so that the asphalt, which is difficult to desulphurize, is desulphurized, but not to the splitting of carbon-carbon bonds which would lead to the formation of products of lower molecular weight. With the procedure according to? · According to the invention, sulfur is naturally removed from the oils5, but this type of sulfur removal can be proportionate easy to get to. In other words; By splitting carbon-carbon bonds, as in known cracking processes, the result is a product other than heavy fuel oil, and such processes are outside the scope of the invention. at

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The present process produces relatively little material with boiling points below the onset of boiling the starting material fed to the hydrogenating desulphurisation system.

As mentioned earlier, the hydrogen comes along with the output material is fed through line 32. In the reactor conventional ones are used for hydrogenative desulphurisation Reaction conditions, e.g. in the case of a hydrogen partial pressure from 70 to 350, preferably from 70 to 210 kg / cm. Hydrogen partial pressures of 105 ^ ia 175 kg / cm are particularly preferred. The gas circulation rate can be 3.56 to 356 Nm / 100 1 and is preferably 53 f 4 to 173 NmVIOO 1, and preferably the Sas contains 85 # or more hydrogen. The molar ratio of hydrogen to oil can be between about 8: 1 and 80%.

Ss is an essential feature of the invention that a hydrogen partial pressure of at least 70 kg / cm is applied Throwing the asphaltic oil up to what is required Desulfurize degrees, this Mdndest hydrogen partial pressure can be used to bring the hydrogen to the reactive surfaces of the asphaltene molecules. The activity of the hydrating desulfurization is not through the entire reactor pressure, but through the chemical activity, expressed by the partial pressure of hydrogen, certainly.

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The temperatures in the reactor in which the desulphurisation takes place can be in the range from about 343 to 482 ° C. and are preferably in the range from about 360 to 427 ° C.:

Of the catalyst beds 62, 64 and 66 shown in FIG. 1, each can, a. larger volume on iron than the previous bed. Optionally, in your reactor 4 'be arranged to 6 beds of catalyst, and each catalyst bed may be a -um £ 25, £ 50, 100 $> or even more groES sere amount of catalyst contained as the directly before and / continuous. ■. ·.: ■ '* · -. -_. . Γ -

Since there is no protective chamber, line 54 leads directly to the reactor. The outlet in line, 54 mixes with the hydrogen stream from line 67 »valve., 69, line 70 and valve 72, so that a mixture of hydrocarbons and hydrogen is fed to the top of the reactor through line 74. When passing through the catalyst bed. 62 this heats up. Electricity-as a result of the exothermic ^: reaction of the hydrogenating desulphurisation. The temperatures between the various catalyst beds can be controlled by direct cooling with hydrogen "supplied through line 76, valve 78, manifold 80 and" line 82, valve 84 and manifold 86. Finally, the reaction mixture flows through the catalyst bed 66 and then, e.g. with a sulfur content of eWa 1 percent by weight, out of the reactor. _ - \ - -. ,. ' ... ...

Mg, 2 shows folgendesr When an asphaltic crude residue containing 4 $ sulfur, by passing through a;. Hydrogenating Entsctafefelungszone as the reactor 6Q of Figure 1, containing a 1 "Grewiehtsprozent sulfur, is processed above 349 ° 0-boiling product, boil f more than 80 "of this product at and above 349 ° G (your initial boiling point of the starting material) when the average reactor temperature is raised to the aging of the catalyst to compensate. but as soon as the reaction temperature is increased to 427 C, there is an excessive hydrogenating cleavage to lower boiling products

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a drop in the curve due to the formation of products that boil below the onset of boiling of the starting material. At this point, a product boiling above 349 ° C can be mixed with a A sulfur content of 1 percent by weight can only be achieved at the expense of an excessively strong hydrogenative cleavage.

\ I ± e is shown below, -the method of the invention enables the effective removal of more than 75 i * of the oil in asphaltisehen sulfur contained and avoids aie by the resistance of these oils related difficulties. ■;. '. ■■'■; ·

The effluent withdrawn through line 88 (Fig. 1) is / is fed to a high pressure flash evaporation chamber 9Q in which the light hydrocarbon gases, the hydrogen sulfide _f the hydrogen and a controlled portion 'AeT. relatively highly desulphurized saturated and aromatic hydrocarbons are driven off through line 92. The use of this flash evaporation chamber 90 between the process stages is an essential feature of the invention. Careful selection of the stripping temperature at the respective process pressure determines the correct amount of light oil which must be removed from the charge of the second process stage. The reason for distilling off a certain amount of light oil results from Pig. 3- · · ■

In Pig. 3 is the composition of one above 34-3 ° C boiling hydrocarbon oil, which has different proportions of Aromatics, saturated hydrocarbons ,. Resins and Asphaltenes contains, in its] passage through a reactor for hydrogen desulfurization, such as the reactor 60 of the Fig. 1 :, shown. 17ie Pig. 3 shows the resin and takes Asphaltene content of the starting material with increasing. Sulfur deprivation constantly off, because carbon-sulfur bonds are separated and thus fragments of the molecule are broken off Accumulation of these molecular fractions is reflected in the increase in the amount of saturated and aromatic hydrocarbons, especially aromatics, of lower molecular weight contrary. This increase in the aromatic content of the liquid is

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advantageous because the aromatics represent _s oils non-soluble in saturated hydrocarbons, a solvent for the extremely viscous resins and asphaltenes ·. They desulfurization of each fraction below "to SSTT a sulfur removal of 75 fi gone, and at this point reach .'- the curves for the resins and asphaltenes Pla" Château _s indicating that no- further fragments are cleaved from them. At the same time 'and the total content of aromatics and saturated hydrocarbons does not take: to increase, but an increase in saturated hydrocarbons goes hand in hand with a decrease in AromatengehaltSo -Dies.be- · suggested that in a Schwef elenfzug of 75 * tf ^a fife Aromatics tend to saturation, which is not just a useless water-. substance ν means consumption, but also the remaining ·. Resins and asphaltenes deprive them of their aromatic solvent, while only the amount of saturated hydrocarbons, which act as a mere dispersant, is increased.

At 75 ~ P * Ozentiges sulfur removal the (sulfur compounds against further desulfurization "are resistant, so that a. Further ¹ desulfurization with a decrease of the aromatic content and a sharp increase" in saturated hydrocarbons goes hand in hand. Both. Factors are for the further removal of sulfur and for overcoming the difficulties caused by the great resistance of the oil at this point, because when 75 % of the sulfur content is withdrawn, most of the sulfur that has not yet been withdrawn is enriched in the resins and asphaltenes . If aromatics are lost, the viscous resins and asphaltenes are less well kept in solution,. ■ vi while the formation of saturated hydrocarbons leads to excessive dispersion, so that the remaining sulfur compounds are too diluted and thus * the reaction rate decreases. .

Therefore, when operating the first desulfurization reactor, one can determine the aromatic content of the oil as it passes through it determined by the reactor, and the oil should be withdrawn from the reactor if its aromatic content does not increase any further.

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increases · This is according to Pig. 3 "with 75 percent desulfurization the case. The aromatics content of the oil as it passes through the reactor can increase by 25 to 40 percent by weight or increase resistance. Even a slight increase in the aromatic content fcentration of, for example, 2 to 5 or 10 percent by weight is already an advantage. However, the aroma content is important do not increase so much that the aromatics dilute the sulfur compounds to be removed too much.

It is assumed that the sulfur removal up to 75 Φ consists in the splitting off of edge sulfur from the complicated heterocyclic ring structure of the asphaltene molecule with the simultaneous formation of aromatic hydrocarbons, primarily as a result of the separation of carbon-sulfur bonds on the arc matic rings on the edge of the moiekül. This production of aromatics is amazing because Aa-. Tphaltenmolekül © for the formation of colloidal crystallites)! odor aggregates tend »if they are not in a sufficient state of solution. Therefore, up to a draft of $ 75, there is sufficient aromatics formation in place to keep the asphalt particles in solution and the action required for desulphurisation of the asphaltenes. Allow hydrogen and catalyst on the inner, heterocyclic sulfur. With this 75 percent desulfurization, the ratio of aromatic to saturated hydrocarbons is so low that there is not enough solvent, but too much diluent, to remove the permanent sulfur.

Hence 'it is necessary to check the aromatic content of the asphaltic Keep feed to the second hydrogen desulfurization zone under control. This can be done by one a controlled amount of the normally liquid oil product of the first. Drives off or otherwise separates the desulfurization zone, e.g. by distillation or flash pre-evaporation and subsequent partial condensation of the driven off, hydrocarbons with circulation in order to achieve that the Electricity has the correct aromatic content.

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It is therefore essential that the second The desulfurization reactor contains so much aromatics that the resins and asphaltenes in the oil are kept in solution and all Asphaltene aggregates that have already formed, for example, adhere again be cut up and dissolved * At any given output temperature, a certain Amount of aromatic hydrocarbons normally an even larger amount of saturated hydrocarbons is driven off - with certain crude oils it can happen that through this rapid evaporation more aromatic than saturated hydrocarbons are driven off, and in this Palle is the only advantage of this flash evaporation in the removal of excess dispersant. In practice, a "compromise must be made by." the second desulphurisation stage together with the feed * a sufficient amount of aromatics is supplied so that the. Resins and asphaltenes are kept in solution in sufficient quantities and properly desulphurised without reducing the amount of aromatics is so large that the total amount of aromatic and saturated carbon fed to the second stage lenhydrogen dilutes and disperses the sulfur compounds to be extracted from the oil too much, thereby reducing the reaction rate. The volume of aromatic or saturated hydrocarbons, which at a given Stripping temperature can be removed is in Pig. 4 shown. '- ". - ..' ·

The solid lines in Pig. 4 show an analysis the content of the effluent from the first desulphurisation stage of saturated and aromatic hydrocarbons for various stripping temperatures measured at atmospheric pressure. If the stripping temperature between the two process stages is 2G0 ° C, all those boiling above 260 ° C reach Aromatics in the second process stage and are available there for the solvation of the resins and asphaltenes. At an output temperature of 260 ° C, however, the hydrocarbon exists 81 percent by volume of electricity is made up of saturated hydrocarbons and 19 percent by volume from aromatics. Through this

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Amount of aromatics together with the even larger amount of saturated hydrocarbons that necessarily accompany the aromatics, however, the asphaltic compounds can be diluted too much, so that the reaction rate drops. On the other hand, if the output temperature between the process steps is 427 ° ö, is. The ratio of aromatic to saturated hydrocarbons in the oil feed to the second process stage is higher, which is favorable for bolvation with the least possible dilution, on the other hand, but it can be the total amount of aromatics that goes into the second process stage at a stripping temperature of 427 ° E is not large enough to dissolve the resins and asphaltenes and reduce their viscosity to such an extent that desulphurisation is possible. So you have to find the right balance between aromatic and saturated hydrocarbons in order to achieve the cheapest desulfurization. This point can easily be determined through experiments with the starting material to be desulphurized. If, for example, the residue is used as the starting material, which corresponds to the solid lines in Pig. 4 corresponds to the distillate shown, the best results are obtained by flash evaporation at that 5 ° temperature which results in a separation at about 343 ° C. regardless of the pressure at which the flash evaporation is carried out. As a result, there is not only a sufficient total amount of aromatics in the process stream, but also a proportion of about 72 percent saturated hydrocarbons to 26 percent by volume of aromatics in the distillate obtained from the flash vaporization. " As will be shown below, working with too large an amount of aromatics in the bisulfurization reaction can be just as detrimental to sulfur removal as working with too few aromatics.

The dashed lines in FIG. 4 correspond to another possible distribution of saturated and aromatic hydrocarbons in the distillate obtained in the flash evaporation; in this case begin, η the aromatics

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in a distillate fraction with an initial boiling point τοη 288 ° C to outweigh. But since at an output temperature of 288 G all lighter components pass into the distillate, the saturated hydrocarbons predominate. Aromatics Amount still in the total distillate. ■ ·

A certain amount of fluid, which is driven off by depuration evaporation, is withdrawn through line 92 (Fig. 1). Depending on the type of starting material and the conditions used in the desulfurization reaction, the material driven off through line 92 can be, for example, about 5 to 60 percent by weight of the liquid discharge from desulfurization reactor 60? preferably this material is about 10 to 35 weight percent of the effluent from this first desulfurization reactor. Suitable stripping temperatures are, for example, between about 260 and 427 * 0, preferably between about 516 and 371 ° GV (these temperatures relate to atmospheric pressure and of course change depending on the process pressure). A particularly preferred output temperature between the two process stages is 343 ° C. The most advantageous amount of liquid that is driven off or otherwise separated from the discharge of the first desulfurization stage can easily be determined by searching. The distillate is driven off through line 92 of a high. high-pressure rapid distillation plant 94 supplied, in which hydrogen j hydrogen sulfide and light hydrocarbon gases. · are separated from a liquid hydrocarbon fraction. The gases are drawn off through line 96 and cleaned and separated in the gas recovery system 97, where they. go through multiple washes and the like. Then all the hydrogen sulfide that has formed in the reactor 60 is withdrawn through line 93. The hydrogen now freed from hydrogen sulfide and light gaseous hydrocarbons is recovered from the plant 97 and. through line 103 through line ¹ 99 ^ü ^ he leads the cycle gas compressor dead for reuse in the process, in the circuit overall ·. The liquid fraction not driven off during the rapid distillation is removed from the rapid distillation plant 94

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withdrawn through line 98.

The residue fraction of the relaxation digestion plant 90 withdraws through line 100 and becomes with make-up hydrogen mixed through line 102, valve 1Ö5 and line 107 is fed. Furthermore, circulating hydrogen can be fed into the make-up hydrogen line 10? · From line 1-3 through line 109, valve 115 and line 115 are introduced. If necessary, supplemental hydrogen can be added using suitable Valves (not shown) are transferred directly from line 103 into line 108. The combined stream can the oven 106 to be heated there ^ if so desired. However, the furnace 106 is not essential required, since the stream 104 is already uxf for the Feed through line 108 to the second desulfurization reactor 110 required desulphurisation facilities are located can. ... . ... . _

Temperatures and pressures in reactor 110 can be the same as in reactor 60. Likewise, a catalyst of the same composition can be used in reactor 110 as in reactor 6Q. It should be noted here, however, that the desulfurization catalyst is even more active for the removal of nickel and vanadium than for the removal of sulfur. Most of these metals are already removed from the oil in the first desulfurization reactor 60. The strongest separation of these metals occurs at the inlet of the reactor 60. The second desulfurization reactor 110 only needs to remove the last amounts of these metals from the oil, and therefore not as large an amount of metals is deposited on the catalyst in this reactor as on the catalyst in the reactor I} in more detail, the catalyst of the first ¹ Verfalirensstufe cut off the oil grögsten the portion of the metals and loses much faster than the catalyst activity in the second stage, ·

The desulfurized effluent from the reactor 110 flows through line 114 into the quick distillation unit 116, \ io light gases such as hydrogen, hydrogen sulfide lind light hydrocarbons are driven off. This gas stream passes through line 118 into the high-pressure rapid distillation

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plant 94. A residue fraction containing the asphalt-containing product stream prepared according to the invention is fed through line 120 to the distillation column 122. By line 124 a sulfur-containing stream This stream is removed from distillation column 122 is withdrawn from "acid ¹¹ Gas and" acidic "water .. passes (not illustrated V / ice) in a gas treatment plant, -.. Where the sulfur is recovered therefrom A Heavy fuel fraction is withdrawn from the distillation column 122 through line 132. This heavy gasoline can be used as an ifase liquid to separate the light hydrocarbons from the hydrogen conveyed through line 96 (in a manner not shown). A fuel oil fraction or a heavier one Fraction can be taken off through line 133 and used in the manner described below in order to obtain further aromatics for the desulfurization reactor 110 of the second process stage. A product stream: flows out of the distillation column 122 through line 134. This desulphurized oil contains asphalt ene and resins and is particularly valuable without further mixing, all heating oil, V7eil.it contains less than 1 weight percent sulfur. This heavy, asphaltic heating oil contains, for example, about 0.3 to 0.5 weight percent sulfur or less and thus corresponds to the strictest requirements laid down by ordinances on the sulfur content of "heavy fuel oils." will be presented. · -. '· ". · -'" - ■ - · · '..

The process according to the invention gives a yield of products with higher boiling points than the initial boiling point of the starting material a fed to the first desulfurization reactor of not less than 40 or 50 and up to 80 or 90 percent by weight. In the process there is hardly any hydrogenative cleavage and the hydrogen consumption is generally in the range from only 2.67 to 26.7 and preferably in the range from 5.34 to 17.8 Nm ⁵ per 100 l of starting material. The charge to the desulfurization reactor can have an initial boiling point of not less than 191 ° C and preferably has an initial boiling point of at least 327 or 343 ° C.

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Therefore, the proportion of components having boiling points below 191 ° C ₁ 327 ° C or 343 ° C at the trodukt you wide level not hydrodesulphurisation more channels 50 or 60 weight percent "in general, or preferably even only 10 -or 20 weight percent * with the method according to the invention can be a Auegangsgut with a. Beginning of boiling Above 343 ° C »eg use a vacuum distillation residue with an initial boiling point in the range of 399 to 482 ° C or more». In this case, the proportion of the constituents boiling below 343 ° C. in the product of the second stage of the hydrogenative desulphurization is not more than 10 or 20 percent by weight. Accordingly, the process of the invention can be referred to as an "essentially cleavage-free process".

The fuel oil product of each desulphurisation plant has a total content of asphaltenes and resins of at least 10 or 20, possibly from 30 or 40 up to 30 percent by weight of the amount _{t contained} in the feed to the first desulphurisation plant. The fuel oil product of the second desulfurization plant has a preferred total resin and asphaltene content of at least 40 to. 50 or 70 up to 90 percent by weight of the amount contained in the feed to the second desulphurisation zone * This is another indication that the resins and especially the asphaltenes can be desulphurised without being completely destroyed »as was previously the case was *

An amendment made by Pig. 1 explained procedure is shown in Fig. 5 in the form of a simplified flow diagram.

. A topped crude oil is fed through line 220 to a distillation plant 222 operating at atmospheric pressure, from which through line 224 a light asphalt-free distillate fraction with a boiling end of 332 to 345 ° 0 and through line 226 a heavy, aephaltige fraction boiling above 332 to 343 ° C. a sulfur content of 4 percent by weight is deducted. The residue fraction containing asphalt flows through line 226 to a vacuum distillation

- 20 30982 4/1090

plant 228, from which further light oil is withdrawn through line 230 will. This light oil is mixed with the pipeline 224 withdrawn lighter fraction and passed with the hydrogen fed in from line 235 via line 234 into the desulfurization zone 232. Zone 232 can be connected to a conventional gas oil desulfurization catalyst at one temperature for example from about 204 to 427 ° C, but at one work at a lower hydrogen pressure (e.g. below 70 kg / cm), when it is used to desulfurize an asphaltic oil. The asphalt-free distillate can be found in the zone 232 easily completely desulfurize and is fed through line 236 to the distillation plant 238, from which one of hydrogen, Hydrogen sulfide and light gases existing overhead fraction withdrawn through line 240 and, as described above, for the production of hydrogen and light hydrocarbons is worked up.

A fraction containing aromatic compounds, heating oil and higher-boiling components is extracted from the distillation unit 238 removed through line 244. From the vacuum distillation plant 228 an asplial-containing oil flows through line 246, which e.g. have an initial boiling point of around 538 ° C and around 5.5 Ge? Weight percent sulfur. This oil is made from Line 246 passed through a mixing zone 250 in which the asphalt-containing Oil is mixed with a controlled portion of the aromatics-rich fraction withdrawn through line 244 to ' to dissolve the asphaltenes and resins contained in the oil. and the oil on the. to bring the desired viscosity. Then it will be, hydrogen. fed through line 248. The heaviest 'product from the distillation unit 238 can optionally with the product withdrawn through line 268 are mixed.

• The one containing the dissolved resins and asphaltenes Asphaltic fraction passes through line 252 in a first desulfurization zone 254 r where they -under the for the Desulfurized reactor 60 of Figo 1 conditions described v / ird. The runoff from zone 254 is reduced Sulfur content and flows through line. 256 to the between the expansion evaporation plant located in the two process stages 258, from which hydrogen, hydrogen sulfide,

309824/1090

L I. ^ i \ i> J ■ & / - ' ___..__- -

light hydrocarbon gases and a controlled! 'close to aromatic and saturated hydrocarbons by conduction 260 is deducted. Here, as described above, the Output temperature chosen so that the feed for the

■ ti '■, | ^h .

Second zone of hydrated desulphurisation for solubilization the most favorable content of asphaltenes and resins having aromatic solvent; From the flash evaporation system 258, a drain is withdrawn through line 262 and mixed with hydrogen, which is fed through line 264 will. This oil stream mixed with hydrogen passes into a second desulfurization system 266, in which the sulfur content of asphaltic oil is reduced to below 1 percent by weight v / ird. From the second desulphurisation plant 266, which works in the same way as the plant 110 in Pig. 1, the heavy oil product is withdrawn through line 268 and then, as described above, for the separation of hydrogen sulfide, light gases and the like worked up. .

Like Pig. 5 shows this procedure is used with a parallel management by adding an initially lighter fraction separated from the crude oil is desulfurized and is used to give the heavy, asphaltic part of the crude oil the viscosity and viscosity required for desulphurisation to give the required solvency. -

Another modification of the term explained by 'Mg' Γ: fahr ens is in Pig. 6 shown. According to Pig. 6 becomes an as ~ phaltisches oil fed through line 320 to the distillation plant 322, where it is in an aromatic arcie faction that passes through 324 is withdrawn, and an aromatic-rich fraction which contains 4 # sulfur. A rich in aromatics Asphaltic oil is supplied from still 322 by conduit 326 deducted. For example, the still 322 can be operated in this way that an asphaltic fraction with an initial boiling point of about 343 ° C is obtained from it.

The asphaltic oil withdrawn through line 326 is mixed with hydrogen supplied through line 328 and the mixture passed through line 330 to a desulfurization plant 332, which is described in the tfeise above

- 22 -

309824/1090

is betrayed. The discharge from zone 332 flows through line 334 into a Hoeharuek expansion evaporation system 336, from the e.g. the maintenance) 42.7 ° G boiling portions through conduction 338 are carried out * while an above 42? C. boiling asphaltic oil is withdrawn through line 340.

From Pig. 4 * It can be seen that at a stripping temperature of 427 ° C., a relatively high ratio of aromatic to saturated hydrocarbons is obtained. The overall 'samtaromatengehalt of the oil is, however, at this output temperature erforderliehe of that for the resins and asphaltenes are less than is desirable * Therefore vird in the gas flowing through line 340 oil introduced through line 342 a controlled amount of an aromatic-rich _fraction: LÖSEV. erinogen-.

.supply. The combined stream is then mixed with hydrogen supplied through line 344 and passed to desulfurization reactor 346 where the sulfur content of the asphaltic fuel oil is reduced to below 1 percent by weight . . ■ ■ -... '■ · "- ■. ■ · ■ -';. · · '·'" ..

. The effluent from zone 346 flows in via line 348 the distillation plant 350, from which an aromatic-rich fraction is withdrawn through line 352. A controlled portion of this fraction withdrawn through line 352 is passed through line circulated and piped with the asphaltic oil 340 mixed as described above. From the still 350 draw the light gases through line 354 while a practically sulfur-free, asphaltic,! heavy fuel oil through line 356 is obtained «Practically all asphaltenes and resins fed to still 350 are in line 356 along with the asphalt-containing fuel oil won. The circuit flow in line 342 is free, 'of asphaltenes. The asphaltenes do not become the first

. Desulphurisation zone in the circuit, because it is there that. Deactivate catalyst prematurely. You also will be not led to the second desulphurisation zone in the circuit because they have already been desulphurized and one such Circulation would have no purpose.

~ 23 09824 / 109Q

•. ■ ■. ■ * ■■ ■■■, ■■■: ■■ · ■■ ■ ·: ■■ ■ · ·

"In the manner explained with reference to Mg." 6 is obtained from the product stream a-light, desulphurized, · aromatics- ^ rich solvent for the asphaltic material.

Another modification of the invention is shown in FIG. Here the asphaltic starting material is fed through line 420 to a distillation plant 422 in order to remove the starting material and produce a feed which is fed through line 426 to the hydrodesulfurization process is fed. The asphaltic fraction is led by

426 withdrawn from the distillation unit 422 and with a controlled Amount of a product rich in oil supplied through line 428 is mixed. The oil in line 428 can be a in the range of about 204 "to 566 ° G, preferably from about 343 "to 482 ° C, boiling, aromatic-rich fraction. Dem Oil mixture is then admixed with hydrogen, which is fed through 430 is fed and a stream boiling above about 343 ° C and containing about 4 weight percent sulfur is used introduced through line 432 into zone 434 for hydrated desulfurization. This facility can be found at 366 to 421 or

427 0 can be operated. A process with a sulfur content of about 1 percent by weight is discharged through line 436 of the flash evaporation plant 438 supplied. The plant becomes a fraction consisting of light oil and gas, which practically contains all of the hydrogen sulfide produced and withdrawn through line 440. This stream can, for example, have an end of boiling point of 343 ° 0.

. . An example, above 343 ° C boiling asphaltißches oil is mixed with hydrogen which is fed through line 442 and introduced through line 444 into a second Entechwefelungszone 446 that can be also operated at 366 to 421 or 427 ⁰ C. The effluent from the second desulfurization zone 446 has a sulfur content of less than 1 fo and is fed through line 448 to the J-50 distiller. An asphalt-free, aromatic-rich fraction is withdrawn from the distillation plant 450 through line 452 and passed through line 428 for mixing with the asphaltic oil feed for the first desulfurization zone 434

- 24 - 309824/1090

■ "# Γ ■ ■ ·

Cycle guided. The distillation unit 450 turns hydrogen sulfide and light gases withdrawn through line 454, while a low sulfur asphaltic fuel oil through line 456 is removed. The part of the oil in the pipe. 452, the is not recycled, the product can be mixed in line 456 to reduce its sulfur content.

The one in Pig. 7 thus makes use of a low-sulfur, aromatic-rich product stream in order to make the asphaltenes and resins soluble in a heavy starting material for desulfurization with a relatively high initial boiling point. . . _;

A modification of the system explained by Mg. 7 ·· is in Pig. 8 shown.

The procedure according to Mg. 8 is similar to that according to FIG. 7i in FIG. 8, however, the through line 440 drainage of an expansion evaporation system equipped with cooling coils, withdrawn from the expansion evaporation system 438 441 supplied. Hydrogen sulfide and light gases are withdrawn through line 443. The rest Heavier effluent is withdrawn from the flash evaporation system 441 through line 445 and through the 'pump 447 is fed to the second desulfurization system 446 after mixing with the oil from line 444. "

The method of operation according to Mg. & Enables the expansion evaporation system 438 can be operated at the same temperature as the desulphurisation systems 434 and 446. At the same time, the expansion evaporation system, equipped with cooling coils and operating at a lower temperature, enables 441 the separation of hydrogen sulfide and light gases and the reintroduction of an oil with the most favorable aromatic content and start of boiling.

If, for example, it is determined that the most favorable output temperature between the two process steps one; Vfert of 343 C. Corresponds to atmospheric pressure, and if the Desulphurisation plants 434 and 446 can work at 371 ° C the flash evaporator unit 438 also at 371 ° C

- 25 -

30982W10 90

work. Then, however, the expansion evaporation system 441, operated at the lower temperature, works ^{: at} 343 C and this enables the portions boiling above 343 C to be returned through line 449

Therefore, in the embodiment according to Pig. 8 not It is necessary to lower the temperature of the oil in line 436 and to reheat the oil fed in through line 444.

According to Fig. 9 is an asphaltic, sulfur-containing Hydrocarbon oil through line 520 of the still fed, where this oil is broken down into light gases, which are drawn off through a pipe, and an aromatic fraction withdrawn through line 5.26 and used in the manner described below *. The aromatic-rich fraction can have an initial boiling point of 343 ° G.

An asphaltic residue fraction with an initial boiling point e.g. The desulphurized effluent from zone 532 is transferred through line 534 to the flash evaporation system 536. As described above, the most favorable output temperature has been determined beforehand, and a light oil fraction which is saturated and contains aromatic hydrocarbons, is driven off together with light gases and hydrogen sulfide and withdrawn through line 538. ; . .

The asphaltic oil. becomes from the flash evaporation plant 536 withdrawn, mixed with hydrogen from line 540 and fed through line 542 to the second desulfurization zone 546. In addition, the asphaltic loading. for zone 546 still mixed with the aromatic-rich oil fed in through line 526. The distillation process in the system 522 is carried out under such conditions that the oil in line 526 the for maximum solatization the most favorable boiling range and asphaltenes contained in the feed to the second desulfurization zone 546 Aromatic content on v / eist. The effluent from zone 546 is fed through line 548 to still 550, from which

- 26 309824/1090

the asphalt-containing heating oil separated in it flows off through a pipe. Light gas is withdrawn through line 554 and heavy gasoline through line 556 and treated in the usual manner. . ·. '■■■■ · ■ ■.

; '.'-..- ■ Example 1 .

. . An asphalt-containing, topped crude oil with a sulfur content of 4.09: weight percent is combined with hydrogen passed into a desulfurization zone, in which a Mckel-Cobalt-Molybdenum catalyst on an alumina support with no cleavage activity. The hydrogenative desulfurization takes place at temperatures from 343 to 438? C and one Hydrogen partial pressure of Ϊ4Ό kg / cm, and the resulting ' asphaltic product is made at a temperature equal to atmospheric pressure corresponds to a temperature of 343 ° 0, the flash evaporation subjected to a drain with the most favorable content of aromatic and saturated hydrocarbons to. obtain. The asphaltic asphalt that was withdrawn from the flash evaporation system and boiling above 343 ° C The fraction has a sulfur content of 1.09 percent by weight and is fed to a second desulfurization zone, where desulfurization takes place also in the temperature range from 343 to 438 ° G on a catalyst of the same composition as in FIG first stage is carried out. ''

A heavy fuel oil with a sulfur content is obtained of 0.58 percent by weight. The distribution of sulfur in the various Fractions of the subject to desulphurization Oil is shown in Table I.

-v 27 -

309 824/10 $ Q

Table I.

Saturated
Hydrocarbons .. aromatics

Resins

Asphalt ene

CO I. CD ro CO OO OO I. Is-) r » CD CO CD

Feeding the first desulphurisation zone

Fraction. Weight -f »

Sulfur content of the fraction, weight-9 «

Feeding the second desulphurisation zone

Fraction, wt .- $

Sulfur content of the practice, G ew. -Fo

Fuel oil product fraction, wt.

Sulfur content of the fraction, w / w 1.7.98
3.42

22 24 O, 80 22 34 O, 49

55.45
5.04

60.45
1.12:

16.73

5.59

13.76
2.37

61.91. 12.72

0.56

1.56

• ^: -33 - ■ · ■■ ■■■ - ''. ■:

From Table I it can be seen that the sulfur in one Asphaltic starting material, which has a total sulfur content of 4.09 percent by weight, relatively evenly saturated hydrocarbons, aromatics, resins and asphaltenes. If, however, the initial good is through the first Ent ^ · Sulphurization zone passed and the fraction with 'a boiling end of 343 ° C with a total sulfur content of 1.09 percent by weight, have.die saturated and aromatic hydrocarbons have lost most of their sulfur content, i.e. they only contain 0.80 or 1.12 percent by weight sulfur, while the resins and asphaltenes only have a sulfur content of 2.37 or ".4" 95 Ge ■ Most percent have been desulphurized, for them as much less. ger sulfur. has been withdrawn. After the second escape significant percentages remain Sulfur only in the resins and asphaltenes; . ',.'. *

Further, it can be seen from Table I, the aromatics content of the starting material .that after rapid evaporation after the first process stage of 55.45 weight percent to 60.45 weight percent, and finally in the product to 6t, 91 - · weight, ^increased: is. ^- At the same time, the weight ratio of aromatics to the sum of resins and as- · • phaltenes increases from about .2: 1 to about 4: 1 that the asphaltic oil contains enough aromatics so that the resins and asphaltenes remain in solution and any asphaltene aggregates that have already formed are dissolved again and become accessible with the desulfurization. Furthermore, the table shows that 'it is essential to contain the presence of an excess of liquid that aromatics and in particular gesät- i-saturated hydrocarbons, which is erfordorlieh to Löslichinaclien of the resins and asphaltenes on that amount of addition to avoid, since such Excess sulfuric liquid has no other effect than dispersing and diluting the sulphurous resins and asphaltenes and thereby reducing the likelihood of their encounter with the catalyst. It should also be noted that;

30982 4 * 710 9 * 0

the aromatic content of the feed to the second stage Terfahr ens higher (60.45 percent by weight) than that of the first Beschikkung Yerfahrensstufe (55 _f 45 weight percent). This is largely due to the flash evaporation carried out between the process stages up to a stripping temperature of 343 ° C, at which a relatively larger proportion of saturated hydrocarbons is transferred to the discharged Iieichtölstrom than to aromatics. In each stage of the process, the weight ratio of aromatics to the sum of resins and asplialtenes for the purpose of dissolving the latter should be at least 1: 1 and preferably 1.5 or 2: 1: and can even be 4 or 5 * 1. The aromatics can already be contained in the starting material, they can be added through circulation, or they can be generated on site by a reaction.

It can also be seen from Table I that the saturated hydrocarbons driven off are the. are most desulphurized fraction and therefore have needed the least, to be led by _r, the second Yerfahrensstufe desulfurization. . . . .

• The following example illustrates the persistence of a asphaltic starting material against the removal of sulfur, if one tries to reduce the sulfur content below i $ without from to make use of the procedure according to the invention.

Leg game 2

A Kuwait crude oil tapped at £ 22, which is an asphalt fraction and contains 5.43% by weight of sulfur, is subjected to desulfurization. The start of boiling of the crude oil is at 291.degree. C. and the boiling range extends to above 760.degree. C. After the sulfur content has been reduced to 4.77 percent by weight the start of boiling is 268 ° C, and the boiling range reaches above 760 ° C. If you continue with the desulfurization and the sulfur content reduced to 1.41 percent by weight, the boiling point is 265 ° C, and the boiling range extends to above 760 ° C. But if the sulfur content is reduced to 0.83

-30 309824/109 0

·· '. · ■ "-" ■■■■ 3-1' · '■■ ■ ■:' ■:. ■■■ ■ '·· ■

If the weight percentage is reduced, the onset of boiling drops from its initial value to 50 °. G to 241 ° C, and the, Siede oe rich extends to over 760 C.

The results of this experiment are shown in Table II. . . · .- ■ "'" ".-'".

Table II ■ ' ■' ■ · ■ '.

',. . . Output. . . ·

Well Desulfurization

Sulfur content,. . . . , '.

'· Wt. 5.43. 4.77, 1.41 - 0.83

Sieäbereich, ° C. 297-760 + 268-760 + 26.5-760 + 241-760 +. Desulfurization, # '. · ■ - .. 12.2' 74.0 .85.0 · *

Specific · ·. ·.

Weight. . . , 1,025.4: 1.0093 0.9484 0.9321

The above values show that the sulfur contained in the starting material becomes very resistant to further desulfurization after about 74 percent desulfurization; In a desulfurization by 12 $ of the boiling point is lowered to 268 ° 0, while the initial boiling point is decreased only to 265 ° G at a desulfurization by 74 i ". However, if you want to achieve 85 percent desulphurisation, the start of the SöLede falls to 241 ° G. In the one-stage method, with a desulphurisation above T4 percent, the hydrogenative decomposition begins to outweigh the hydrogenative desulphurisation, i.e. carbon-carbon bonds are created instead of carbon. Split sulfur bonds. ■

! Table III shows the composition of the goods during the desulfurization reaction. .

- 31 ^

3098 2 4/1090

EaJbelle III

Initial good , GewI- $

Finding the composition during desulfurization, 'wt. $

Desulfurization, # - 12.2 74 ** 85 Saturated coals "26.1 hydrogen 11 16.7 56.6 33.2 Aromatics 39 41.2 15.1. 49.9 Resins 32 25.7 2 | 2. t5.3 Asphaltenes. 18th 16.4 1.6

It can be seen from this that with an increasing degree of desulphurisation the amount of resins and asphaltenes decreases as these are converted into saturated and aromatic hydrocarbons will. ■ ·

Table IV gives a comparison of the molecular weights of the Aromatics, saturated hydrocarbons and residual coraponents in desulfurization.

Table IY Output

Change in molecular weight during desulfurization

Desuppression, $>

Saturated hydrocarbons, molecular weight

Aromatics,

Molecular weight

Total residue components, Molecular weight

1080

12.2

430.0
490.0

590.0

400
- 530

490

410 ^ 400

420

Table IV shows that the molecular weight of the residue components decreases as the degree of desulfurization increases, but does not become significantly lower than the molecular weight of the saturated and aromatic ones formed at the beginning Hydrocarbons. This molecular weight distribution bev / c is that in the splitting of carbon-sulfur bonds in the resins and asphaltenes form hydrocarbon fragments which lie in roughly the same molecular weight range.

• - 32 -

309824/1090

genes like the saturated and aromatic ones, which are well contained in the starting point Hydrocarbons.

: Example 3

In order to explain the influence of the dilution and the concentration of the resins and asphaltenes in the charge of the second process stage on the desulphurisation rate in the second process stage, one works at an output temperature of 343 ° C with a starting material that has already undergone a single-stage desulphurisation process during the quick evaporation behind permanent asphaltic residue is subjected in a second Verfahrensstuf ^ _t hydrodesulfurization, wherein a reaction rate constant of the desulfurization yields of about 85th The reaction rate constant of the desulfurization is calculated in the usual way according to the following formula i '·;' - ·. -

kg oil '^ kg oil ^: kg sulfur h.kg catalyst ■'

This reaction rate constant can also be given by the equation /

k - (I - A

are expressed in which Sp kg sulfur per kg oil in the product, Sjb kg of sulfur per kg of oil in the starting material and LHS ¥ · volume parts of oil mean catalyst per hour per part of space. .

For comparison purposes, the residue at 343 ° C. carried out flash evaporation a desulphurized. . Heating oil with a boiling range of 204 to 343 ° C and a Sulfur content of 0.07 percent by weight added. This Heating oil consists of about half of saturated hydrocarbons and half of aromatics. If you pass this asphaltic raw material through a second desulfurization stage conducts, the reaction rate constant of the desulfurization decreases down to 75. The excessive dilution of the charge in the second stage of the process thus reduces the reaction rate the desulfurization is reduced, even if aromatics are added. .

- 33 -

1824/10 90.

In a further comparative experiment, the charge the lowest boiling point in the second desulphurisation stage 30 percent by weight driven off, so that the charge is now the residue of a carried out at 427 ° 0 Flash evaporation corresponds to. In this case, the reaction rate constant of the desulphurisation decreases in second procedural stage to 40, which indicates insufficient solatization the resins and asphaltenes. This clearly shows that the amount of saturated and the aromatic hydrocarbons, which together with the resins and the asphaltenes in the second process stage are introduced, has a significant effect on the reaction rate in this process stage, and that a Too large an amount of diluent is just as disadvantageous An effect on the reaction rate of the desulfurization can be such as an insufficient amount of aromatic solvent. solvent.

·· ■■ '■ ■ - Example 4 . '. · ■. . .. '. ".'';.': /

In order to determine the influence of sufficient, as opposed to excessive, solubilization of an asphalt-containing starting material, a high-boiling residual oil with an initial boiling point of 427 ° C is desulphurized by 76.2 percent by weight. A second sample of the same starting material is first diluted with 30 percent by volume of a lower-boiling gas oil that has previously been desulphurized by 90 to 95 percent by weight.By adding the gas oil, which has a high aromatic content, the degree of desulfurization is increased to 80.3 percent by weight .- _%

A further sample of the original material is used for comparison purposes diluted with 40 percent by volume of gas oil and, as above, subjected to hydrogenation desulfurization. In this case the desulfurization activity decreases and the degree of desulfurization falls to 76.3 percent by weight. If you get 64 percent by volume If gas oil is added, the degree of desulfurization drops even further. ter to 69.4 percent by weight. The results of these experiments

- 34 "* .309824 / 1090

are compiled in Table V. . _:

lEabelle V / ...

* Influence of dilution with Gasol

Gas oil, V0I.-3S. . 0 30.0 40.0 64.0

Degree of desulfurization,. ■ '. * - *

Weight -4 76.2 80.3, 76.3 69.4

Deprivation of vanadium,. . . -. ' ■ -. ^;

, Wt. ~ £. 83.5 78.6 74.6. 77, ö.

The above values show that by diluting an asphaltic oil with gas oil at the beginning of the hydrated desulphurisation due to the killing power of the! in. the <■ 'gas oil aromatics contained for · resins "obtained and asphaltenes an advantage. This advantage but can be a more than offset excessive amount of diluent because the diluent then in the first" line than 1 dispersant for the sulfur-containing molecules affects ^r and thereby the speed of the desulphurisation reaction. settles. An excessive amount of thinner can also have a detrimental effect on the desulphurisation because it causes an excessively high throughput rate in the desulphurisation reactor. ....

· -. Example 5 "',;.

An experiment is carried out in the first and the second process stage a Mckel-Cobalt-Molybdenum catalyst with a carrier made of aluminum oxide with particle ^ diameters of 0.79 mm are used-. In the first stage

■ ". / - ■ ■ the catalyst has topped off during the desulfurization of a Kuvrait oil with a sulfur content of 4 percent by weight to one of 1 percent by weight at an hourly rate Fluid flow rate of 0.8, an initial temperature (Temperature at the beginning of the experiment) of 366 G and an end temperature (temperature at the end of the experiment) from 421 ° C a service life of 6 months. In the second stage of the process, the life of the catalyst is ^ , even longer. From the! Weight percent sleep! entlial

30 9 8.24 / 1090.

Partial sequence of the first process stage is through flash evaporation the portion with a boiling point ("based on atmospheric pressure) of 343 ° C driven off, and the residue is used together with hydrogen in the second process stage desulfurized to a sulfur content of 0.5 percent by weight. The starting temperature in the second stage is 366 ° 0, and the temperature after 170 days is only 406 ° C; The experiment can be continued until the temperature has reached 421 ° C. In this way, the e:? Ste and the second process stage in the process according to the invention 3i 4, 5, 6 or even 7> 8 or even 12 months at an hourly liquid throughput rate Volume base from 0.1 to 10 or preferably from 0.3 to 1.25 work. The life of the catalyst is in the second Process stage longer than in the first process stage.

3098 2 Λ / 1090

Claims (1)

Patent claims ί Λ.} ¥ experience for the hydrogenative desulphurisation of asphaltic oils, which can be broken down into a light oil fraction containing aromatic and saturated hydrocarbons and an asphaltic fraction containing asphaltenes and resins, characterized in that the oil is passed together with hydrogen through a zone of hydrogenating desulphurisation , in which the aromatic content of the oil increases as it passes through the zone, and the oil is withdrawn from the zone at the point beyond which the aromatic content of the oil does not rise any further. 2. Terfahren according to claim 1, characterized in that the weight ratio of aromatics to the sum of resins and asphaltenes in the hydrogen desulfurization zone holds at least 1: 1. 3. Terfahren according to claim 2, characterized in that the weight ratio of aromatics to the sum of resins and asphaltenes in the hydrogen desulfurization zone holds between approximately 1.5: 1 and 5: 1. 4. The method according to claim 1, characterized in that the oil is removed from the point from the hydrodesulphurisation zone subtracts at which the sulfur content of the oil has been reduced by about 75 percent by weight. 5. The method according to claim 1, characterized in that the starting material is a topped crude oil with an onset of boiling used above about 316 ° 0. - 37 -309 8 2Λ / 1090 6. The method according to claim 1, characterized} that the hydrogenating desulfurization is carried out on a catalyst, which has a carrier without cleavage activity. 7. The method according to claim 6, characterized in that the hydrogenating desulfurization is carried out on a catalyst, whose support consists essentially of aluminum oxide. 8. The method according to claim 1, characterized in that one works under such conditions that the from the zone the effluent withdrawn from the hydrodesulfurization contains at least 20 percent by weight of the asphaltenes and resins contained in the asphaltic fraction used as starting material were contained. 9. The method according to claim 8, characterized in that one works under such conditions that that from the zone the effluent withdrawn from the hydrodesulfurization contains about 20 to 80 percent by weight of the asphaltenes and resins contained in the asphaltic fraction used as starting material were included. 10. The method according to claim 1, characterized in that one works under such conditions that the effluent withdrawn from the hydrogen desulphurisation zone does not more than 60 percent by weight from below this boiling point of the starting material fed to the zone of hydrogenating desulphurisation boiling components. 1t. Process according to claim 1, characterized in that one of the sulfur content of about 1 percent by weight showing the course of the zone of hydrating desulphurisation, of light gases containing hydrogen sulphide, one consisting essentially of saturated and aromatic hydrocarbons existing light oil fraction and an asphaltic one Fraction consists of the asphaltic fraction and at least one part of the light oil fraction of a second zone the hydrogenating desulphurisation, in which the sulfur - 38 - 30982A / 1090 content of the effluent reduced to less than 1 percent by weight
will, 12. The method according to claim 11, characterized in that one is the weight ratio of aromatics to "the sum of resins and asphaltenes in both zones of the hydrogenative desulphurisation to at least 1: 1 13. The method according to claim 12, characterized in that the weight ratio of aromatics to the sum of resins and asphaltenes in both zones of hydrogenation desulphurisation holds between approximately 1.5: 1 and 5: 1. - 39 309824/1090