DE3246678A1 - METHOD FOR SELECTIVE PRODUCTION OF MEDIUM DISTILLATE HYDROCARBONS - Google Patents

Description

Process for the selective production of middle distillate hydrocarbons

One of the most important properties that a modern oil refinery must meet is its flexibility. The ability to use various raw materials that vary from shale oils and heavy oils to light oils, to be able to use for the manufacture of various products in order to meet the needs of the market is important for profitability. For example More and more raw materials are falling from higher-boiling, qualitatively lower mixtures with more metal-sulfur and nitrogen impurities than those previously used Starting materials. The predicted consumer needs are from hydrocarbons in the gasoline sector to heavier and higher boiling products such as diesel fuels, fuel oils and turbine fuels, above.

Hydrocracking, either in the form of a one-step process or in the form of multi-stage processes, coupled with hydrodesulphurisation and hydrodenitration stages, has been widely used to improve and manufacture poor quality raw materials Manufacture materials covered by gasoline range. Much development work has been done to improve hydrocracking conditions and catalysts.

In tests, catalysts containing only amorphous materials and catalysts containing zeolites were used that are mixed with amorphous materials.

Of the zeolites described in the literature, Y are

(U.S. Patent 3,130,007) decationized Y (U.S. Patent 3,130,006), ultra-stable Y (U.S. Patent 3,293,192 and U.S. Patent 3,449,070) and ultrahydrophobic Y (GB-PS 2 014 970) mentioned. Furthermore, literature references are known which deal with the modification deal of zeolites. For example, US Pat. No. 3,367 describes a reduction in the activity of superactive zeolites by calcination and leaching methods. The catalysts described are found to be particularly suitable for the cracking of gas oils into gasoline. U.S. Patents 3,506,400 and 3,591,488 describe the improvement the stability of the crystal lattice of zeolites by steam treatment and acid extraction. That Product, a stabilized zeolite, can be used for hydrocracking and is stated to be a has improved selectivity, as evidenced by a higher gasoline yield and lower coke production to recognize there.

Other research has focused on the manufacture directed by mid-barrel products. U.S. Patent 3,853,742 describes the hydrocracking of high boiling point feedstocks for the recovery of mid-barrel products using a catalyst, one with steam contains treated zeolite. U.S. Patent 4,120,825 also describes improving the production of mid-barrel products by hydrocracking with a catalyst containing a steamed zeolite,

The invention is based on the finding that middle distillate products in a selective manner through hydroprocessing with a zeolite catalyst with expanded pores can be produced.

The invention relates to a method for the selective production of middle distillate hydrocarbons, which consists in

(a) under hydroprocessing conditions a hydrocarbon

, to contact containing feed which boils above about 315 ° C (600 ⁰ F) with a catalyst comprising a hydrogenation component and a zeolite with expanded pores, consisting of a faujasitic zeolite which has been subjected to a steam treatment and then dealuminated and

(b) To obtain a hydrocarbon-containing effluent, of which more than about 40% by volume ^{boil above about 150 °} C. (300 ^° F) and below about 370 ^° C. (700 ^° F).

The invention is based on the knowledge that faujasitic zeolites, which after a high-temperature steam treatment have been dealuminized, surprisingly stable and with respect to the production of middle distillates are active from higher-boiling feeds. Under Faujasite Zeolites are synthetic or natural aluminosilicates, which have the crystal structure of the large-pored Zeolite, faujasite, own to understand. These zeolites include faujasite, zeolite X, zeolite Y as well Zeolites based on these. For example, numerous methods are known for treating zeolite Y. for producing "decationized Y", 'ultra-stable Y "," Z14-US "or the like. The preferred faujasitic zeolite is zeolite Y, derivative zeolites are also possible.

which have the crystal lattice properties of zeolite Y The most preferred faujasite zeolite is an ultra-stable Y zeolite which has a sodium content of less than about 0.5% by weight (as Na ₃ O).

In their generated form, the large-pore zeolites typically contain considerable amounts of alkali metal. Since the alkali metals tend to poison the acidic sites of the zeolite, standard ion exchange methods become standard applied to remove them.

The alkali metal content (calculated as oxide) is preferably set to below 5% by weight prior to heat treatment as well as less than about 200 ppm by weight in the finished zeolite.

The treated faujasite zeolite is calcined at high temperatures in the presence of water. During this high-temperature steam treatment, it is expedient for at least 2% by weight of the atmosphere above the zeolite to consist of water, preferably more than 10% by weight and in particular more than 25% by weight. The most convenient method of calcining the zeolite is to place the zeolite, which has been ion-exchanged in an aqueous medium, in an autoclave and to carry out the steam treatment under its own pressure. The temperature of the steam treatment stage is normally above about 54O ⁰ C (1000 ⁰ F) and preferably above 65O ⁰ C (1200 ⁰ F) and very particularly preferably above 760 ⁰ C (1400 ⁰ F). The duration of the steam calcination can vary from 1/2 hour to 24 hours or more.

The steam calcination appears to remove the aluminum from the crystal lattice and volatilize it of silicon to repair the holes left in the grid by the aluminum are. In this way, the integrity of the grid is

going maintained and a complete breakdown avoided. However, some degree of crystallinity is lost. The steam treatment also generates large cracks and breaks in the crystal particles. The aluminum removed from the grid appears to be amorphous aluminum oxide deposits to form in the lattice pores and channels. These amorphous deposits are created by the dealuminization method removed. Dealuminization typically consists of leaching with steam treated zeolite with organic chelating agents such as EDTA, or with organic or inorganic acids. Dilute inorganic acids, particularly hydrochloric acid and sulfuric acid, are most preferred. Will Acids are used, the pH of the leach solution is preferably below about 2.If the pH is too high, then the dealuminization is too long, while if the acid concentration is too high, the crystal lattice of the Zeolite can be attacked. Typical acid solutions are between about 0.01 and about 10 N.

The finished zeolitic product has a smaller crystal lattice and a higher silica: alumina molar ratio than that normally obtained. With steam treated and dealuminized Y zeolite typically has a cubic cell constant of less than about 2.44 µm (24.40 Å) and a silica: alumina molar ratio greater than about 10: 1, and especially greater than about 20: 1. The finished one dealuminized product also has a higher surface area than the starting material. The steam / calcination treatment also surprisingly improves the catalytic properties of ultra-stable Y zeolites.

Although the aluminum oxide content of the steam-treated and leached faujasite zeolites is very low in comparison to the starting materials / they nevertheless surprisingly retain their activity and gain noticeably in selectivity with regard to the valuable middle distillates.

The finished catalyst composite contains both the faujasitic zeolite and an inorganic oxide matrix.

Inorganic oxides are standard carriers for zeolites that are processed for hydroprocessing. Aluminum oxide, silicon dioxide, magnesium oxide, titanium dioxide and combinations thereof may be mentioned. The preferred support is made of alumina. A variety of methods can be used to combine the zeolite with the refractory oxide. For example, the zeolite can be ground with a hydrogel of the oxide, which is optionally followed by partial drying and extrusion or pelletization to form particles with the desired shape. Optionally, the refractory oxide can be precipitated in the presence of the zeolite. This is done by increasing the pH of the solution of a refractory oxide precursor such as sodium aluminate or sodium silicate. As mentioned above, the combination can then optionally optionally dried, tableted, pelleted, extruded, or otherwise deformed, and then calcined, for example at a temperature above 315 ° C (600 ⁰ F), usually above 430 ⁰ C (800 ⁰ F ). Processes that produce larger pore size supports are preferred over processes that produce smaller sized pores upon cogelation. Will further

the steam treated zeolite is added to an acidic solution of an inorganic oxide precursor, then the leaching stage can be carried out in situ in the co-gelling mixture without a separate leaching stage. 5

The catalyst should be less than about 50, preferably less than about 30 weight percent of the zeolite based on the dry weight of zeolite and refractory oxide. However, the zeolite content should exceed 0.5% by weight and usually above 2% by weight.

The finished catalyst composite contains at least one hydrogenation component. The hydrogenation component consists typically a transition metal or a Group IV-A metal, which is usually a Group VI-B or VIII metal or a combination of these metals or their oxides or sulfides.

The hydrogenation components preferably consist of molybdenum, Tungsten, nickel and cobalt as metals or oxides and sulfides thereof. Preferred compositions contain more than about 5 wt%, preferably about 5 to about 40 wt%, molybdenum or tungsten, or both, as well at least about 0.5 and generally about 1 to about 15 wt% nickel or cobalt, or both, determined as the corresponding oxides. The catalysts are often presulphided before use because of the sulphide form these metals have a higher activity, selectivity and activity retention. 30th

The hydrogenation components can be added by any desired method. You can either use the zeolite or added to the carrier or a combination of both

the. Optionally, the components of group VIII the zeolite by grinding, impregnating or Ion exchange added and the components of group VI, d. H. Molybdenum and tungsten, with the refractory oxide by impregnation, joint marriage or joint precipitation.

The hydrogenation components can be added during any stage in the preparation of the catalyst. For example metal compounds such as sulfides, oxides or water-soluble salts such as ammonium heptamolybdate, ammonium tungstate, Nickel nitrate or cobalt sulfate, by joint grinding, impregnation or precipitation either the. Zeolite or the refractory oxide or both components can be added before the zeolite is finally calcined and is combined with the carrier, or after its final calcination, but before combining with the refractory oxide. These components can be the finished catalyst particles by impregnation with an aqueous Solution or a hydrocarbon solution of the soluble compound or the precursor can be added.

The hydrocarbon feeds required to carry out these processes are used, boil mainly

2-5 slightly above about 315 ° C (600 ⁰ P). Preferably at least about 90% of the feed boils between about 370 and about 650 ^° C (700 and 1200 ^° F). Feed materials with these properties include gas oils, vacuum gas oils, coker gas oils, deasphalted residues, and catalytic cracking cycle materials. The feed to the hydrocracking zone generally contains at least about 5 ppm, and usually between about 10 ppm and 0.1 weight percent nitrogen as organonitrogen compounds. She can fer-

ner substantial amounts of mono- or polynuclear aromatic compounds corresponding to at least about 5 and generally about 5 to about 40 volume percent aromatic content.
5

The catalysts used to carry out these methods have a superior stability, activity and Barrel selectivity, the reaction conditions must nevertheless be chosen in such a way that the desired Conversion rates can be achieved while conversion to less desirable low boiling products is kept to a minimum is held. The necessary conditions, to this Satisfying the objective depends on the catalyst activity and selectivity as well as the properties of the Material from, for example the boiling range, also the content of organonitrogen content and aromatic content, as well from the structure. Furthermore, these conditions are based on a compromise in terms of overall activity; H. Turnover per pass and selectivity. These systems can, for example, at relatively high conversion rates in the On the order of 70, 80 or 90% conversion per pass can be operated. In general, higher conversion rates are required a lower selectivity. A compromise must therefore be chosen between conversion and selectivity. Of the Balancing the reaction conditions to achieve the desired goals is within the discretion of the person skilled in the art.

The reaction temperatures generally exceed about 26O ⁰ C (500 ⁰ F) and are usually above about 315 ° C (600 ⁰ F), preferably between 315 ° C and 480 ⁰ C (600 ⁰ F and 900 ⁰ F), the added amounts of hydrogen should be at least about 11,324 liters per barrel, and are usually between about 56,620 and about 424,650 liters per barrel (400 and 2000 to 15,000 standard cubic feet per

Barrel). The reaction pressures will exceed 14 bar (200 psig) and will usually be between about 32 and 207 bar (500 to 3000 psig). The hourly liquid space velocities are less than about 15, and are preferably between about 0.2 and about 10. The overall conversion rate is determined primarily by the reaction temperature and controlled the liquid hourly space velocity. The selectivity is generally reversed proportional to the reaction temperature. she will not so strongly influenced by reduced space velocities with otherwise constant conversion. The reverse is the Selectivity usually improves at higher pressures and hydrogen addition rates. The most expedient conditions for the conversion of a specific charge for a predetermined product can best be passed through Converting the feed at various temperatures, pressures, space velocities and hydrogen addition rates Achieve, taking the effect of each of these variables and choosing the best compromise in terms of overall sales and selectivity play a role: 'Play.

The conditions should be chosen such that the total conversion rate corresponds to the production of at least about 40% and preferably at least about 50% of the products ^{boiling below about 370 °} C (700 ^° F) per pass. The mid-barrel selectivity should be such that at least about 40, and preferably at least about 50% of the product is in the middle distillate range. The method is capable of conversion levels of more than about 50% per pass in selectivity above 60% with respect to middle distillate products boiling between 205 and 37o ⁰ C (400 and 700 ⁰ F) to maintain.

The process can be carried out in a single stage hydroprocessing zone be performed. It can also be the second tier of one Be a two stage hydrocracking process with the first stage Nitrogen and sulfur from the feed before contacting removed with the middle distillate producing catalyst. The procedure can also be the first stage one Be multi-stage hydrocracking process. In one implementation As a first stage, the middle distillate production zone also removes nitrogen from the feedstock and desulfurizes it this. Furthermore, it enables the second stage to be carried out more effectively, so that more middle distillates are produced overall than with other processes. This operating mode with the first switched Middle distillate production zone, which is followed by at least one further hydroprocessing zone particularly preferred for increasing middle distillate production.

The invention is illustrated in the accompanying drawings explained. Show it:

1 shows the difference in the fouling rate and activity between an amorphous standard catalyst, which is used for the production of middle distillates, and that for carrying out the invention Catalyst used in the process;

Figure 2 shows the effect of the amount used in the leaching solution Acid on the silica: alumina molar ratio the zeolite;

3 shows the effect of the amount of acid used in the leaching solution on the crystallinity of the product

product obtained zeolite compared to the zeolite steamed as a reactant;

4, 5 and 6 show the superiority of the process according to the invention with regard to the production of middle distillates. Catalysts that contain steam-treated and leached, steam-treated and untreated ultra-stable Y zeolites are compared. 4 illustrates the higher middle distillate diesel yields due to the steam-treated and leached catalyst. FIG. 5 shows the lower heavy naphtha yields achieved by the steam-treated and leached catalyst, and FIG. 6 shows the lower aromatics content of the middle distillate obtained by the steam-treated and leached catalyst. The yields are plotted against the conversion to below 354 ° C (67o F ^0).

7 shows in comparison the pore size distribution of a water vapor treated and a water vapor treated and leached Y zeolite.

example 1

A catalyst that has been steamed and leached Y zeolite containing is made with a non-zeolite nickel-tungsten catalyst (Silicon dioxide / aluminum oxide / titanium dioxide cogel base) which is used for the production of middle distillate is compared to compare activity and fouling rate. The zeolite catalyst contains 15% by weight

Zeolite which is steamed at 800 ° C for 1 hour and washed with 1 η hydrochloric acid. The zeolite is ground with aluminum oxide and has a final metal content of 3.9% by weight nickel and 2 0.5% by weight tungsten. The loading exists from an Arab straight-run heavy gas oil with the following Characteristics:

⁰ API 21.8 388 Aniline point 78 ° C '436 S, wt% 2.62 N, ppm 846 499 Distillation (D-1160), 540 ⁰ C: St / 5 332 / 10/30 401 / 50 451 70/90 468 / 95 / EP 514 /

The reaction conditions see a liquid hourly space velocity of 0.75, a pressure of 96.5 bar and 141,550 1 hydrogen / barrel feed. The results can be seen from FIG. 1. The zeolitic catalyst is much more active at a significantly lower fouling rate than the non-zeolite catalyst.

Example 2

A series of experiments will be carried out to

The effect of the acid wash on the silica: alumina molar ratio and the crystallinity of the zeolite obtained as the product should be investigated. The starting material consists of NH.Y with a sodium content of less than 1% and a silicon dioxide: aluminum oxide molar ratio of 5.1: 1. The zeolite is \ hour at 800 ⁰ C of a water vapor nimbly lung subjected and then washed with acid. Wash solutions are prepared based on the volumes of concentrated hydrochloric acid per gram of zeolite (0.8 ml concentrated HCl. Is the stoichiometric amount of acid used to increase the SiO-ZAl ₂ O ₃ molar ratio from 5: 1 to 30: 1 is required). The measured acid is then diluted to approximately 1.1 M or 8.5 M and the zeolite washed with the resulting solution. The silica: alumina molar ratio is determined by neutron activation analysis. Percent crystallinity is measured as a percentage of the X-ray diffraction intensity relative to Na-Y. As is apparent from FIGS. 2 and 3, appears to be the 0 Si0 ₂ / Al ₂ 0 ₃ molar ratio and the percentage of crystallinity linearly and in an unexpected way with the amount of input, _f acid, the t \ ir Processing> ier washing] r . ~ solution has been used and does not vary with the strength of the washing solution. It is preferable to maintain at least 50% crystallinity, measured as X-ray diffraction intensity relative to Na-Y, in the product as compared to the starting material.

Example 3

A series of tests are carried out on the products to compare obtained with various zeolitic hydrocracking catalysts. The catalysts

A and B are subjected to a steam treatment for 1 hour at 800 ^° C. and the catalyst B is leached with 1N hydrochloric acid to remove the aluminum oxide debris. The zeolites are combined with aluminum oxide by grinding them together and then extruding them. The extrudate is impregnated with the hydrogenation metals using standard methods. The catalysts have the following properties:

.Catalyst A BC

Zeolite

15 wt% zeolite wt% Ni wt% W cell constant, nm

water
treated
ultra stable
Y Steam-
treated
and entalumi-
nized ul
trastable Y ultrasta
biler Y 15th 15th 15th 6.9 4.0 3.4 17.2 21.0 20.0 2,444 2,436 2,458 5: 1 29: 1 5: 1

The catalysts are tested in a one-stage hydrocracking process using a light Arabian straight run vacuum gas oil as the feed having the following properties:
25th

⁰ API ⁰ C 22.9 Aniline point, 81 ° C S, wt% 2.15 N, ppm 877

Distillation (D-1160),

⁰ C:

St / 5 339/374

10/30 381/413

50 448

70/90 467/503

95 / EP 511/536

The reaction conditions see a liquid hourly space velocity of 1.2, a hydrogen pressure of 101 bar and 141,550 1 hydrogen / barrel of the feed recycle gas before.

The extremely achieved by the process according to the invention Desired product properties are shown in FIGS. 4, 5 and 6. The steam treated and leached Zeolite produces significantly more middle distillate (Fig. 4) with lower aromatic content (Fig. 6) than that steamed and untreated Y zeolite. Further the feed cracking to naphtha materials occurs at a significantly lower rate Extent (Fig. 5) with the steam-treated and aluminized zeolite catalyst.

Example 4

A treated with steam (746 ⁰ C) Y-zeolite having a silica: alumina molar ratio of 5.1: 1 is washed with an approximately 1 M HCl solution (0.74 cc of concentrated HCl / g-zeolite). The leached product has a silica: alumina molar ratio of 9.6: 1.

The pore size distribution for both materials (relative pore volume dV / d (log d) as a function of the pore diameter) are shown in comparison in FIG. 7.

Claims (15)

Patent Attorneys · European Patent Attorneys ■ ■ - - Br. -W. Müller-Bore f Dr. Paul Deufel Dipl.-Chom., Dipl.-Wirtsch.-Ing. Dr. Alfred Schön Dipl.-Chem. Dr. Müller-Bore and Partner POB 880720 D-8000 Munich 86 Werner Hertel Diploma Phys. Dietrich Lewald Dipl.-Ing. Dr.-Ing. Dieter Otto Dipl.-Ing. C 3395 S / sm Chevron Research Company Market Street,
San Francisco, CA 94105 / USA Process for the selective production of middle distillate hydrocarbons Claims M .J Process for the selective production of middle distillate hydrocarbons, characterized in that (a) under hydrocracking conditions a hydrocarbon-containing feed which ^{boils above approximately 315 0} C (600 ⁰ F) / with a catalyst composed of a hydrogenation component and a zeolite with expanded pores, which consists of a faujasite zeolite which has been subjected to a steam treatment and then dealuminized, and D-8000 Munich 86, SiebertstraBe 4 POB 860 720 Cable: Muebobat Telephone (0B9) 4740 Telecopier Infotec 6400 B - (089} 4740 08 - Telex 5-24285 (b) a hydrocarbon-containing effluent is obtained, of which more than approximately 40% by volume ^{boil above approximately 150 °} C. (300 ^° F) and below approximately 370 ^° C. (700 ^° F). 5 2. The method according to claim 1, characterized in that the faujasitic zeolite used is a Y zeolite is. 3. The method according to claim 2, characterized in that that the faujasitic zeolite used is an ultra-stable Y zeolite. 4. The method according to claim 3, characterized in that the faujasitic zeolite used has a sodium oxide content of less than approximately 0.5% by weight. 5. The method according to claim 2, 3 or 4, characterized in that that the expanded pore zeolite employed has a cubic cell constant of less than approximately 2.44 nm (24.40 Å) and a silica: alumina molar ratio greater than about 10: 1. 6. The method according to claim 5, characterized in that the silicon dioxide: aluminum oxide molar ratio is greater than is about 20: 1. 7. The method according to claim 5, characterized in that The expanded pore zeolite employed is less than about 200 ppm by weight, alkali metal oxide contains. 8. The method according to claim 1, 2 or 3, characterized in that that the faujasite zeolite used dealuminized by contacting it with an acid at a pH less than about 2 will. 9. The method of claim 1,2 or 3, characterized in that the used faujasitische zeolite at a temperature above ungefähr540 ⁰ C (1000 ⁰ F) is subjected to h to a steam treatment for more than about. 1 10. The method according to claim 9, characterized in that a stagnant steam treatment carried out will. 11. The method according to claim 1, characterized in that the hydrogenation component composed of a nickel, cobalt, molybdenum or tungsten compound or mixtures thereof and the catalyst used also has an inorganic oxide matrix. 12. The method according to claim 11, characterized in that the matrix consists of aluminum oxide. 13. The method according to claim 1, characterized in that the charge used ^{boils above about 37 0 0} C (700 ⁰ F) and more than about 40% by volume of the discharge above about 205 ⁰ C (400 ⁰ F) and below about 370 ^{Boil 0} C (700 ⁰ F). 14. The method according to claim 13, characterized in that the charge used is a gas oil. 15. The method according to claim 1, characterized in that in a stage (c) at least one hydrocracking a portion of the hydrocarbon-containing effluent is performed.