NL8101802A - HYDROPROCESSING / CATALYTIC CRACKING PROCESS. - Google Patents

Description

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Hydro-processing / catalytic cracking process.

The invention relates to the processing of hydrocarbons, in particular to a process for the hydroprocessing and catalytic cracking of starting materials contaminated with sulfur / nitrogen into cracked products with a lower sulfur / nitrogen content.

It is well known that "pre-hydrotreating" gas oil subjected to fluid catalytic cracking, i.e., FCC starting materials, can improve the quality of cracked products. The Oil & 10 Gas Journal discloses that both the quality and quantity of cracked gasoline fractions can be improved by hydrotreating gas oil starting materials before catalytic cracking with zeolite fluid cracking catalysts.

US patent 3,726,788 further discloses that hydrocracker starting materials can be advantageously pretreated with hydrogen using excess recycled hydrogen recovered from a hydrocracking process.

While it has been disclosed that catalytic cracking operations can improve by hydrogen pretreatment of sulfur-containing gas oils, the cost of producing -. sufficient hydrogen for such hydrogen treatments in a typical catalytic cracking operation is extremely high. The quantities of hydrogen produce! and available in the normal catalytic cracking process are relatively small, and the amounts of hydrogen required for significant sulfur / nitrogen removal must be obtained from external sources. As a result, relatively few refineries with catalytic cracking units currently operate on hydrotreated starting materials.

It is therefore an object of the invention to provide an improved method for catalytic cracking of sulfur / nitrogen contaminated starting materials.

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It is a further object to provide a process in which sulfur / nitrogenous starting materials can be economically treated with hydrogen to remove substantial amounts of sulfur and / or nitrogen impurities before catalytic cracking.

It is yet another object to provide an integrated hydroprocessing catalytic cracking process in which at least a significant portion of the hydrogen used in the hydroprocessing step is produced during the catalytic cracking operation.

It is yet another object to provide an economical way of obtaining increased yields of low sulfur and high octane gasoline.

These and other purposes will become apparent. . Those skilled in the art from the following detailed description and drawing represent a block diagram of a hydroprocessing / catalytic cracking process illustrating the practice of the present invention.

Normally, the invention contemplates an integrated hydroprocessing catalytic cracking process, in which hydrotreated starting materials are catalytically cracked in the presence of a cracking catalyst, which is at least. 1st 0.1.5 wt% (based on fresh feed) of hydrogen. In the cracked product stream, which hydrogen is recovered and used in the hydrotreating of incoming sulfur / nitrogen contaminated feedstock.

In particular, the use of a. special zeolite-activated cracking catalyst which provides sufficient hydrogen to fruitfully pretreat the catalytic cracker feedstock without a significant increase in the production of undesired coke and light hydrocarbons at the cost of gasoline yield.

More specifically, it has been found that when a typical fluid catalytic cracking unit is operated with ..35 a zeolite cracking catalyst in which the zeolite is exchanged 81018 02 ♦ • - - 3 - against at least 0.5% by weight of a metal selected from the group consisting of silver, copper, nickel, and / or manganese, an amount of hydrogen will be produced during the cracking reaction, which is sufficient to produce the sulfur / nitrogen impurity level of a raw material by pretreatment with hydrogen produced as a by-product of the catalytic cracking reaction significantly decrease.

A more complete understanding of the invention can be obtained with reference to the figure, in which a simplified block diagram shows the basic steps of the present method. In the figure, a hydrocarbon feedstock stream 1, which is contaminated with sulfur and / or nitrogen, is combined with a hydrogen stream 2. The combined hydrocarbon 3 feedstock / hydrogen stream 3 containing 0.03-0.10m hydrogen per kg of feedstock enters a conventional hydrotreater h containing a suitable catalyst for hydrotreating. The hydrocarbon feedstock typically contains 0.5-5.0 wt% sulfur and 0.05-1.5 wt% nitrogen. Usually the sulfur and nitrogen impurities are present as complex sulfur / nitrogen organics.

When the combined hydrogen / feedstock stream enters the hydrotreater U, it is heated to a temperature of 300 DEG-50 DEG C. and contacted with a hydrotreating catalyst, which typically consists of cobalt, molybdenum, nickel and / or tungsten suspended on a suitable inorganic oxide support, such as aluminum oxide. During the hydrotreating step, the hydrogen combines with the sulfur / nitrogen impurities, which are removed from a resulting product stream 5 as a hydrogen sulfide and / or ammonia stream 6 through separator 7 and a scrubber 8.

The hydrotreated hydrocarbon feedstock stream 9, which now contains only about 0.1-1.5 wt.% Sulfur and 0.01-1.0 wt.% Nitrogen, is subjected to a catalytic cracking step in catalytic cracking unit 10, wherein the 8101802 • * * · - k starting material is contacted with a zeolite-containing fluid cracking catalyst. The catalyst used in the practice of the process of the invention is capable of producing significant amounts of hydrogen during the cracking operation. Zeolite catalysts that are particularly suitable are those containing hydrogen-producing metals such as silver, copper, nickel and / or manganese. Catalysts of this type are disclosed in U.S. Pat. Nos. 3,835,032, 3,985,619, and 3,929,621. Suitable catalysts contain 2-50 wt.% Of a crystalline aluminosilicate zeolite which has been exchanged and / or impregnated with a combination of metal ions combined with a suitable inorganic matrix.

Typically, the faujasite type zeolite is exchanged with a combination of cations to produce cation exchange concentrations of 1-10 wt% of a metal ion consisting of CuO, AggO, NiO, MnO 2, or mixtures thereof, the remaining cation exchange positions are supplemented by MgO, KEgOg and / oi <H. Particularly suitable zeolites consist of ΒΕ ^ Ο ^ or H exchanged Y-type faujasite, co-exchanged with 20 1-3 wt. $ CuO, AggO, Μη ,, Ο or IliO.

The exchanged faujasite is combined with an inorganic oxide ground mass, which may consist of clay, silica-alumina gel, silicon oxide, Al ^ 3 or any com - \ * - aV ·· 1. bi wet. .. .. The working method. preparation of fluidized · '· - ···.

Catalysts used in the practice of the process of the invention are typically set forth in U.S. Pat. Nos. 3,957 * 689, 3 * 912,619, and 3 * 867,308.

As shown in the figure, the catalytic cracking unit 10 provides both cracked products, stream 1, and off-gas, stream 12. The offgas is generated in the catalytic regeneration step, whereby coke and carbonaceous impurities are oxidized using a catalyst regeneration. ring airflow. Typically, the catalytic cracking process is conducted at a cracking temperature of 90 DEG-580 DEG C. and the regeneration of the catalyst at 600 DEG-780 DEG C. The cracked product stream of the 8101802 + + * - 5 catalytic cracking unit is a vapor at a temperature of 490-580 ° C and consists of cracked hydrocarbon products as well as a substantial amount of hydrogen 5, i.e. about 10-30 volume #. The cracked products are separated in a distillation column 11. As shown in the diagram, the separated fractions comprise a residual product stream 20, boiling above about 335 ° C, a gasoline fraction stream 21 with a boiling range of 35-220 ° C, a light product stream 22 with a boiling range of - ^ 2 ° C to + 35 ° C and a dry gas fraction stream 10 23, which consists of hydrogen together with and hydrocarbons boiling below about -k-2 C.

As shown in the diagram, the dry gas fraction stream 23 from the product distillation column I is compressed, separated from any liquid produced by compression in compression separation unit 25 and the hydrogen feed gas stream 26 is then combined with a recycled hydrogen stream 27 Obtained from scrubber 8 and compressed in compressor 28 and separated from liquids in separator 29 to form hydrogen stream 2. The hydrogen stream 2 2 is then mixed with the incoming sulfur / nitrogen contaminate the raw material strocaa 1. It can be noted that while the cracking process considered here will produce sufficient hydrogen for a significant amount of hydrogen treatment, ie sulfur / nitrogen removal, there will be in some cases, where the sulfur / nitrogen impurity level of the starting material is particularly high, additional hydrogen can advantageously be added from external sources.

The invention will now be illustrated in a non-limiting manner with the following examples.

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Example 1

The following is a typical procedure for preparing the zeolites used in the cracking catalysts suitable for use in the process. A 300 gram sample of the sodium type Y zeolite (Na-Y) is mixed with a silica-alumina ratio of b.9 9 with 1.2 liters of water, m.

150 grams of ammonium sulfate. and 11 ml of concentrated sulfuric acid. One reflux leader.

the mixture boils for 1 hour, then recovers the zeolite, washes twice, repeats the exchange 5 and washes once more, then dries the zeolite. By this part of the process, the sodium content of the zeolite is reduced to about 3% by weight. The zeolite is then exchanged with a solution consisting of 3 g of mixed rare earth chlorides (RECl) dissolved in 1.2 l of water. The amount of solution used is allowed to vary to give the desired concentration of the exchanged zeolite. The exchanged zeolite is then washed with water and calcined at 76 ° C for 3 hours, the calcined zeolite (RE-Y) is then exchanged with ammonium sulfate by mixing the zeolite in a solution consisting of 300 g of ammonium sulfate in 3 l of water After washing the zeolite free from sulfate with pure water, it is exchanged with the desired metal ion, in this case copper, by mixing the zeolite with a solution consisting of 16.2 g CuCl 3. Dissolved in 750 ml of water The resulting Cu-RE-Y zeolite containing 2.0 wt% CuCT and 0-18 wt% is then calcined for 3 hours at 538 ° C.

The metal ion used can be either Cu, Ag, Mn, Ni or mixture thereof and can be exchanged using • V ··· '·' ··: "; · ·· * - ·. {. chloride, nitrate, or other aqueous solution form "25" in solution. Zeolite can be prepared with or without RE 2.

When no ^ 2 ^ 3 is used, the RECl exchange step is blurred by an aluminum sulfate exchange, leaving all other procedures the same. Using the above general procedure, the following zeolite samples are prepared: (1) Cu-HY (2.0 # CuO) (2) Cu-RE-Y (2.0% CuO + 8.0 $ RE203) (3) RE-Y (18 $ RE203) (k) Ag-RE-Y (k% AggO + 12 $ RE203) .. 35 (5) Ag-RE-Y (1 $ AggO + 8 W $ RE203 ) 8101802 - 7 - (6) EE-Y (13 $ RE203)

Example 2

To illustrate the high hydrogen yield with comparable gasoline, coke and light gas selectivity obtained with zeolites described above, crack catalyst samples are prepared by combining the zeolite samples 1-5 of Example 1 with a semi-synthetic soil mass consisting of 6j parts by weight of a 25 $ silica-alumina hydrogel 10 and 33 parts by weight of kaolin clay. The results summarized in the following Tables A and B show the results of a fixed fluid bed catalytic cracking engineering plant. These tests were performed after hydrothermal deactivation of the catalysts at the conditions indicated to simulate expected utilization properties of the catalysts in the field. These data clearly demonstrate that the copper and silver exchanged zeolite promoted catalysts provide sufficient yield of hydrogen. An additional advantage is a higher octane gasoline product as compared to a catalyst which does not contain copper or silver. Other yields compare favorably with the catalyst which does not contain copper or silver.

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TABLE · A

catalyst (1) Cu-R-Y (2) Cu-RE-Y (3) Re-Y

zeolite 22 15 12 (wt. $) 5 Deactivation: 810 ° C, 20 W $ steam, 1 atm., 12 hours.

Fixed-fluid bed semi-technical unit results Conditions WHSV ^ 0 U0

Catalyst / oil

10 ratio ^ .0 b.0 ij-.O

Temperature: _i + 95 ° C_

Nutrition: West Texas Gas Oil

Results 15 Conversion: Y% TO, 5 72.0 71.5 H2: W $ FF 'O * 35 0.28 0.0¾ C1 + Cg: W% 0.88 0.9¾ 1.,

Total C3: Y% 7.1 7.5 1, ¾ C3 =: Y% 6.5 6.8 6.8. ., r. ..-. 20 ..., ^ Total .... .Y%,, IQ, 9. 1: 1.5. , ..- 11.5- '% ,. · ..

'G ^' Y% 6.0 6.0 k, 9 iC: Y% ¾, 3 ¾, 8 5.7 + "gasoline: Y% 58.5 61.5 59.5 25 Gasoline conversion ratio: 0.82 0 , 85 0.83 RON + 0: 90.1 88, ¾ 87.8 MOE + 0: 77.8 77, ¾ 77.0

Coke: W # FF 6.0 5.6 5.5 30 FF = based on fresh food 81018 0 2 - 9 -

TABLE B

catalyst As — BE — Y (4) Ag — RE — Y (5) RE — Y (6) zeolite (W $) 10 10 6

Deactivation 810 ° C, 1 atm., 20 W # steam in air, 5 12 hours

Semi-technical installation: 512 ° C, target space velocity per hour 20, 4.0 catalyst / oil ratio, West Texas Gas Oil 10 feed

Conversion:% 64.5 64.5 66.5

Hydrogen: W # FF 0.43 0.21 0.05 C1 + C2: W # 0.91 0.92 1.12 15 Total C3: V% 6.4 6.6 8.3 C3 =: V # 5 , 2 5.5 6.4

Total: 1% 10.2 8.1 9.3

Cjf: 5.9 4.2 4.0 iCu: 3S8 3.4 4.5 20 C5 + gasoline: V% 52.5 5T, 0 57.0

Cc + petrolcanzet-,,. .

•. "" -> ·. " . .·· .··· · ·. · · Ting ratio: 0.82 0.88 0.86

Octane 25 RON + 0: 90.4 89.9 88.8 Μ0Ν + 0: 76.6 76.5 77.2

Coke: 6.2 4.5 4.5 30 8101802

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Example 3

Samples of type Y zeolites were prepared by exchange with the following combination of ions: Ag-Mn, Ag-Mn-RE, and Ni-Mg.

(1) A sample of Ag-Mn-Y zeolite was prepared as follows: a slurry of 330 g (dry basis) Na-Y in 2 liters of deionized water was formed at 60 ° C. A slurry of the zeolite is then formed again in a solution containing 15 g of ammonium sulfate, 1200 ml of D.I. water and 21 g of concentrated sulfuric acid and boil for 1 hour.

This exchange is repeated two more times and the product is washed on the filter until the effluent is sulfate-free. The zeolite is calcined at 53 ° C for 3 hours. A slurry of the zeolite is then formed in a solution containing 3000 ml of water and 300 g. ammonium sulfate and boil the slurry for 2 hours. The zeolite is washed once with 3 L of water at 60 ° C, the exchange is repeated once more, and the zeolite is washed with water until the effluent is sulfate-free. 1/3 of the filter cake is added. g # of 250 ml solution, containing 25 silver mats and 75 g manganese nitrate and aged at 60 ° C for half an hour, filter and wash with 250 ml water. The zeolite is then calcined at 760 ° C for 3 hours to obtain Ag-Mn-Y (8.6 $ Ag ^ O + 1.26 $ MnO ^).

(2) A calcined RE-H-Y zeolite is prepared as follows: a slurry of. 100 g (dry basis) Na-Y in a solution containing 2 g of ammonium sulfate, 26.6 g of concentrated sulfuric acid and 1600 ml of water and boiling for 1 hour. After filtering off and washing the exchanged zeolite with 1600 ml of water, the exchange is repeated and the zeolite is washed with water until the effluent is sulfate-free. A slurry of half of the above filter cake is formed in 800 ml of solution containing 26 g of REC16-6 HO2 and boiled for 2 hours. The zeolite is filtered, washed with 800 ml of hot water and then calcined at 538 ° C for 3 hours to obtain RE-H-Y (6 $ REgO 3).

(3) An Ag-Mn-RE-Y zeolite is prepared as follows: a calcined RE-HY zeolite is prepared as under (2) above, but now using an exchange level of 12 $ RE ^ O ^ in plate from 8101802 V «, - 11 -». m 6 $. The resulting zeolite base is exchanged twice with ammonium sulfate solution, filtered and wash sulfate free. 50 g of the dry base of this product are exchanged with 12.5 silver mtrate and 12.5 g of manganese nitrate for half an hour by boiling in 5 200 ml of solution. The zeolite sample is filtered, washed with 300 ml of water and then calcined at 760 ° C for 3 hours to obtain Ag-Mn-Re-Y (8.0 $

AggO, 1.3 $ ΜηΟ ^ + 11.0 $ REgO ^).

(U) A Ni-Mg-Y zeolite is prepared as follows: 1000 g of dry base Na-Y are washed with water and then exchanged three times by boiling with ammonium sulfate solution, and after washing to sulfate, the zeolite is calcined free 3 hours at 538 ° C. It is exchanged. m zeolite then boil twice from ammonium sulfate solution for 2 hours, then wash sulfate free. For every 100 g dry base of the zeolite, 17 * 5 g NiCl 2 6 2, Ο 15 and 30.0 g MgClg 6 E ^ 0 in 250 ml solution are used. The slurry is aged hot at 60 ° C for 0.5 hour, the filter cake is washed until the effluent is chloride free, then calcined at 760 ° C for 3 hours to obtain Ni-Mg-Y (1.35 # NiO + 1.30 $ MgO).

(5) A calcined RE-Y (18 $ RE ^ O ^) is prepared used in the 20 test mixtures with the metal-exchanged seolites by a method similar to that of (2) above.

. .. Example k ........

From the data of the following Table C, it can be seen that cracking catalysts prepared using zeolite samples (1) - (5) of Example 3 obtain high yields of hydrogen with good cracking activity. These data were obtained by physically mixing 25 wt% of the finished zeolites in an amorphous silica-alumina hydrogel / clay matrix, steam deactivating the mixture at 381 ° C, 2 atm, 100 w steam for 8 hours, followed by activity / selectivity test by micro-activity analysis on a small scale. The microactivity test is carried out at 82 ° C, 16 WHSV, a catalyst / oil ratio of 3 using a gas oil starting material with a boiling point stage of 260-226 ° C.

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TABLE C

catalyst composition microactivity results

zeolites of example 3 conversion, Y% H, W% EP

5 (1) Ag-Mn-Y + (5) RE-Y (10/10) 70.3 0.59 (t) Ag-Mn-Y + (2) RE-HY (10/10) .61, U 0.1 * 1 (3) Ag-Mn-RE-Y (12/0) 6U, 3 0.3 ^ (U) Ni-Mg-Y + (5) RE-Y (U / 8) 65, 5 0.1 * 1 (¾) Ni-Mg-Y (15/0) 55.7 0.20 10

Qew.% Of each zeolite in zeolite / ground mass mixture.

2

Defined as% gas oil feed converted to products boiling 15 below 20U ° C plus coke.

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Claims (4)

1. Process for catalytic hydrocarbon cracking, hydroprocessing a sulfur / nitrogenous feedstock to remove sulfur / nitrogen impurities before catalytic cracking in the presence of a zeolite containing cracking catalyst, characterized in that a) said cracking is carried out with a catalyst producing at least 0.15 wt.% hydrogen, based on fresh feed, in the obtained cracked product stream, b) said hydrogen is recovered from said stream, and c) said hydrogen is used in the hydroprocessing of said starting material. 2. Process according to claim 1, characterized in that said catalyst contains a faujasite type zeolite exchanged with about 1-15 wt.% Of a cation consisting of silver, copper, nickel and / or manganese. Process according to claim 2, characterized in that said zeolite is combined with an inorganic oxide matrix. 20 k. Process according to claim 3, characterized in that as said matrix, silica, alumina hydrogel, 'kiil, silica' sol ', and / or alumina sol are used. 5. Process according to claim 2, characterized in that a rare nature exchanged faujasite type zeolite is also used in said catalyst. 8101802