JPS6240060B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention describes compositions that can be used as catalysts for the cracking of high molecular weight hydrocarbons into low molecular weight products, and more particularly, compositions that contain sulfur and/or precious metals and that can be used to convert feedstocks containing residual petroleum fractions into gasoline and heated It relates to compositions that are economically converted into products such as oils. In recent years, the petroleum refining industry has placed considerable emphasis on optimizing the cracking of high molecular weight feedstocks for the production of gasoline and heating oil products. To meet the demand for these products, increasing amounts of feedstock containing relatively high levels of sulfur and/or heavy metals are being subjected to catalytic cracking. It is generally known that cracking catalysts lose their desirable activity and selectivity properties when contaminated with heavy metals such as nickel and vanadium.
Furthermore, catalytic cracking of feedstocks with high sulfur content releases ecologically unacceptable amounts of sulfur oxides (SOx). Regulations exist regarding limiting the amount of carbon monoxide that may be emitted into the atmosphere from the regenerator stack of a catalytic cracker. It has previously been proposed that SOx emissions from catalytic crackers can be reduced by modifying the catalyst in a manner that retains sulfur within the unit product feed stream. Examples of prior art that reduce undesirable emissions associated with catalytic cracking are US Pat. No. 3,835,031, South African Patent No. 74/4642, US Pat. No. 3,944,482 and US Pat. Commercial catalytic cracking catalysts are available that have properties that allow hydrocarbon processors to reduce carbon monoxide emissions and handle residual oil feedstocks in a relatively economical manner. However, to date, commercial catalysts that can suppress SOx and carbon monoxide emissions and also withstand the deactivation effects of heavy metal-containing feedstocks are not commercially available. The present invention provides a composition of a known type of zeolite fraction catalyst and other ingredients which can be used to process various sulfur and/or heavy metal containing feedstocks to produce gasoline fractions in high yields. producing and ecologically unacceptable CO and SOx
can be used to inhibit or reduce the release of According to the invention, the zeolite comprises: (a) about 12 to 60% by weight rare earth metal exchanged zeolite; (b) optionally up to 75% by weight clay; and (c) an inorganic oxide binder. , clay, and binder are blended into particles in a composition for use as a catalyst for decomposition of hydrocarbons, (d) 20 to 50% by weight of α-alumina trihydrate, and (e) about 0.1% by weight of α-alumina trihydrate. ~20 ppm of platinum, palladium or a mixture thereof. Preferred zeolites in the compositions of the invention are Y-type zeolites; the amount of zeolites can suitably be from 17 to 60% by weight of the composition. The components are combined to form a finely divided catalyst composition according to the following typical manufacturing method: 1. A sodium silicate solution is added to an inorganic acid, such as sulfuric acid, and/or a salt solution of an acid, such as an aluminum sulfate solution. The acidic inorganic oxide sol binder is prepared by mixing with the sol to form a sol having a pH of about 2.9 to 4.0. 2. Add clay and alumina to this sol or sol-forming ingredients. 3. Make a slurry of the zeolite component with water while adjusting the pH to 3.5 to 4.5 as necessary. The zeolite component can be in its synthetic form, containing only sodium metal cations,
Or it can already be ion-exchanged with rare earth metals. 4. Blend this sol/clay/alumina mixture and the zeolite slurry to form a spray dryer feed mixture with a pH of about 2.9 to 4.0. 5 This spray dryer feed mixture is then spray dried to form a particulate catalyst which is washed and/or
or ion exchange to remove soluble salts such as sodium and sulfate, and if the zeolite has not been previously exchanged with rare earth metals, exchange with rare earth ions. The spray-dried composition, washed to remove soluble salts, can then be impregnated with a solution of platinum and/or palladium salts to provide the desired concentration of precious metals, or the precious metals can be deposited onto a granular inorganic oxide support. It can be impregnated and then mixed with the catalyst. Alternatively, the platinum component can be incorporated into the composition in the form of platinum-impregnated microspheres or a separate platinum-impregnated additive such as mullite, alumina or silica-alumina, having a particle size and density similar to the zeolite-containing catalyst. The metal-exchanged zeolite used in the practice of this invention is preferably a rare earth-exchanged Y-type zeolite. Rare earth-exchanged Y-type zeolites are calcined rare earth-exchanged zeolites, such as McDaniel,
CREY as disclosed in U.S. Patent 3,402,996
It may be labeled as a zeolite.
Alternatively, thermally stabilized zeolites such as Z-14-US as disclosed in Maher, U.S. Pat.
It is conceivable that it could be Z-14-US RE. Furthermore, the combination of Z-14-US zeolite with calcined rare earth-exchanged zeolite (CREY), i.e., Z-14-US/CREY can be utilized and/or followed by replacement of the catalyst spray-dried with NaY. It is conceivable that a combination of CREY and NaY to be exchanged can be used. Also available are partially rare earth exchanged calcined zeolites (PCY) as disclosed in US Pat. No. 3,607,043 or rare earth hydrogen exchanged zeolites (REHY) as disclosed in US Pat. No. 3,676,368. Other metal-exchanged zeolites that can be present in the compositions of the invention are calcium foam rare earth excreting zeolites (CaREY). Generally, the type of rare earth exchanged zeolite utilized in catalyst preparation will be determined by the selective properties desired in the final catalyst. For example, when seeking to produce high yields of _C3 and _C4 olefins, which tend to increase the octane number of the gasoline fraction produced, Z-14-US RE, Z-14-
The combination of US and CREY or PCY zeolite was found to be preferable. Furthermore, when considering the utilization of catalysts to treat heavy residual oil feedstocks containing substantial amounts of heavy metals such as nickel and vanadium, rare earth-exchanged zeolites containing about 11-22 wt% rare earth ions It is generally preferred to use zeolite Y (REY). Additionally, it is generally preferred to utilize a zeolite such as CREY when seeking to achieve high levels of SOx suppression and residual oil cracking capability in the stack gas emissions of a catalytic cracker regenerator. The clay component of the catalyst can consist of raw kaolin clay or heat-modified or acid-treated clays, such as metakaolin, as well as other clays such as chlorite. The alumina component of the currently considered catalyst is incorporated into the catalyst in the form of free alumina hydrate, which is commercially available from a number of sources. Free alumina hydrate is commonly referred to as alpha-trihydrate. The alumina in these catalysts, in conjunction with the zeolite content, rare earth and sodium levels, and precious metals, acts as an adsorbent and converter for SOx during the thermal/oxidative regeneration of the catalyst, and in the regeneration portion of the catalytic cracking cycle. During this period, sulfur compounds are retained as sulfur oxides. The regenerated catalyst is recycled back to the cracking zone where the sulfur compounds are reduced to hydrogen sulfide and
This is collected in the product stream from the catalytic cracker and can be subsequently separated by fractional distillation and/or adsorption means. The inorganic sol binders that can be used to make the catalysts of the invention are generally described as acidic sol binders and are made according to the methods described in US Pat. No. 3,867,308 and 3,957,689. These Elliott and Ostermaier patents clearly describe general methods that can be used to make the catalysts of the present invention. The compositions of the present invention can be used in small amounts, i.e. from about 0.1 to
Contains 20ppm of precious metals, platinum and/or palladium. This small amount of precious metal serves to oxidize carbon monoxide to carbon dioxide in the regeneration zone of the catalytic cracker. Additionally, the presence of platinum or palladium is important in suppressing SOx emissions generated through the stack gas in the regeneration zone of the catalytic cracker. When sulfur-containing components are transported from the unit's cracking zone to the regenerator unit via the sulfur-rich carbon formed on the depleted catalyst, the presence of platinum in the regenerator section can lead to oxidation of the sulfur compounds to _SO3 . was found to be promoted and the SO ₃ to combine with the alumina and other metals present to form a stable form of sulfur that is not removed from the regenerator in conjunction with the stack gases. this
The regenerated catalyst containing SO ₄ is then returned to the reduction zone, i.e., the hydrogen atmosphere of the cracking zone, and the SO ₄ is reduced and hydrolyzed to hydrogen sulfide, which is added to the catalytic cracker product stream. remain. Generally, the noble metal component is prepared by adding a spray-dried and washed catalyst composition to a platinum salt and/or palladium salt, such as Pt( _NH3 ) ₄ ( _NO3 ) ₂ and Pd( _NH3 ) ₄ ( _NO3 ) _2.
Preferably, it is added by impregnation with a dilute solution of. Typically, the impregnation process is carried out by spraying the catalyst composition with a solution of the desired metal salt. The compositions of the invention have a high degree of activity against hydrocarbon decomposition. Furthermore, the composition can be designed to be particularly selective for the production of increased octane gasoline fractions by choosing the desired zeolite promoter. Additionally, as previously discussed, the composition is resistant to poisoning by heavy metal, nickel and vanadia components present in the residual oil fraction. Additionally, the composition can be effectively used to control SOx and fuel emissions from commercial contact unit equipment. The composition of the invention in the form of spray-dried particles comprises about
They generally have a surface area of 100-550 m ² /g and a pore volume of about 0.1-0.5. Example Silica gel bonded catalysts were prepared by Ostermaier and
Made in a manner similar to that described by Elliott, US Pat. No. 3,957,689. A buffered silica hydrosol binder was prepared as follows:
An acidic alum solution was prepared by adding 8.0 mL of an Al ₂ SO ₄ solution containing Al ₂ O ₃ . 40% of the hydrogen ion equivalents in the resulting solution are aluminum
Existed as Al ⁺⁺⁺ . Acidic alum solution to high speed mixer 555c.c./
It was then mixed with a 18° Be sodium silicate solution with a SiO ₂ /Na ₂ O ratio of 3.25. This silicate solution was fed to the mixer at a rate of 1.5/min. The resulting hydrosol is 2.5-3.0
It contained a 20% excess of the acid-aluminum sulfate needed to neutralize the Na ₂ O present in the silicate. To produce 10,000 g of final catalyst (dry basis), 3,500 g of alpha-alumina trihydrate was added to 30,000 g of silica-alumina sol to form a slurry. After mixing is complete, 10 g of 3500 g in deionized water
of CREY zeolite (pH adjusted to 4.0 with dilute sulfuric acid) was added to the slurry with thorough stirring. After vigorous agitation for 5-10 minutes, the resulting slurry was spray dried in a typical pilot plant spray dryer (6 foot Bowen-2 fluid nozzle dryer). Spray-dried materials were washed with ammonium to remove Na ₂ O; water to remove excess sulfate and dried; the final composition was 35% CREY, 30% SiO ₂ and α-trihydrate. Consisting of 35% Al ₂ O ₃ as a material. Add the required amount of dry catalyst to Pt( _NH3 ) ₄ before testing for residual decomposition and SOx reduction ability.
( _NO3 ) onto the final catalyst by impregnating with a dilute solution of ₂
A platinum content of 3 ppm was produced. This impregnated material was compared with a commercial grade catalyst for its metal tolerance using a microactivity test method; combined with. Catalyst activity was determined by Ciapetta and Henderson, Cil & Gas
Jour., Oct. 16, 1967, pages 88-93. The metal tolerance data for this example is summarized in a table that clearly shows a significant improvement over the standard catalyst.

Table: Example Catalysts were prepared using the same materials as in the example procedure; except that the zeolite was NaY, and the spray-dried catalyst was treated with a rare earth chloride solution, after washing with ammonium sulfate, with 7.5% by weight of RE. Exchanged to ₂ O ₃ level. After rare earth exchange, the catalyst was further washed with water (to remove excess chloride) and dried. EXAMPLE A catalyst was prepared by combining a silica-alumina gel containing 80% _Al2O3 material with a silica hydrosol binder, alpha _- alumina trihydrate. The final composition was as follows: 25% Al ₂ O ₃ (α-trihydrate), 27% (80%
_{Al2O3 ,} 20% _SiO2 gel), 25% NaY and 23
% _SiO2 (as binder). The composition was spray dried, washed with ammonium sulfate, exchanged with rare earth chloride to a level of 4.5% by weight RE ₂ O ₃ and impregnated with 3 ppm platinum. Example A catalyst was prepared according to the method of the example, but the zeolite additives were 17% NaY and 12% Z-14-
US (as described in Maher and McDaniel, US Pat. No. 3,293,129), 25 in the form of the α-trihydrate
% Al ₂ O ₃ , 16% kaolin clay and 30% SiO ₂ as binder. After spray drying, the catalyst was washed with ammonium sulfate and
Exchanged with rare earth chloride solution to a level of 4.3% by weight RE ₂ O ₃ and impregnated with 3 ppm platinum. Example A catalyst was produced by the method described in the example, but
The zeolite additive consisted of 25% NaY, 25% _Al2O3 in the _form of alpha-alumina trihydrate, 27% kaolin clay and 23% _SiO2 as a binder. As in the previous example, the slurry of catalyst was spray dried and then washed with ammonium sulfate;
It was then exchanged with rare earth chloride solution to a level of 4.5% by weight RE ₂ O ₃ and impregnated with 3 ppm platinum. Test Example 1 To demonstrate the ability of the catalyst of the present invention to adsorb and fix sulfur oxides at high temperatures, a sample of the catalyst of the example was compared with a sample of a commercial catalyst (CBZ-1). This commercial catalyst is silica-alumina/
It consisted of rare earth metal exchanged Y-type zeolite in a clay matrix. Catalyst sample, 2000ppm
of SO ₂ , 4% O ₂ and the balance N ₂ for 12 hours at a temperature of 1150°C (621°C). Samples of the catalyst were then analyzed for increased sulfate (SO ₄ ) content. The results are summarized in the table below.

[Table] As is clear from the above results, the composition of the present invention has the ability to adsorb SO ₂ in the presence of O ₂ and N ₂ at high temperatures, whereas the conventional CBZ-1 catalyst does not. do not have. The compositions of the present invention also have the ability to adsorb sulfur oxides in the regeneration zone of commercial fluid catalytic cracking units. The adsorbed oxides are reduced to _H2S during the catalytic cracking cycle, and _H2S
It is believed that can be easily recovered from cracked hydrocarbon gas streams. It is therefore concluded that the catalyst of the present invention will have the ability to reduce the emission of sulfur oxides into the atmosphere. Test Example 2 In order to clarify the performance of the catalyst of the present invention on an industrial scale, a conventional commercial catalyst (catalyst A) was first charged and operated in a fluid catalytic cracking apparatus with a catalyst capacity of 400 tons, and then the Example The catalyst of the present invention (catalyst X) prepared in 1 was additionally operated. Note that Catalyst A and Catalyst X had the compositions shown in the table.

[Table] The amount of sulfur in the gas supplied to the device and the amount of sulfur in the gas released from the device was measured, and the results shown in the table were obtained.

[Table] Measurements 1 and 2 were made when the apparatus was operating with catalyst A, measurement 3 was made one week after starting the addition of catalyst This was done 18 weeks after the addition started.
At that point, about 30-35% of the catalyst in the unit was Catalyst X. The average value of the above ratio up to the time of measurement 2 is calculated as follows: 0.0842+0.0795/2=0.0820. Based on the data of measurement 3, it is calculated that one week after adding catalyst X, the amount of sulfur in the released gas decreased to 0.0690/0.0820×100=80%. Also, based on the data from Measurement 4, it is calculated that 18 weeks after adding catalyst Ru. Thus, in tests on this industrial scale equipment, the addition of catalyst X reduced the amount of sulfur released by 31
% was also able to be reduced.

Claims (1)

[Scope of Claims] 1. (a) about 12 to 60% by weight of a rare earth metal-exchanged zeolite; (b) optionally up to 75% by weight of clay; and (c) an inorganic oxide binder, comprising: In a composition for use as a catalyst for the cracking of hydrocarbons, the zeolite, clay, and binder are combined into particles, (d) 20 to 50% by weight of alpha-alumina trihydrate, and (e) approx. A composition comprising: 0.1 to 20 ppm of platinum, palladium or a mixture thereof. 2. The composition according to claim 1, wherein the zeolite is a Y-type zeolite. 3 The zeolite may be used as Z-14-US as necessary.
REY, Z−14−USRE, PCY, mixed with
The composition according to claim 2, characterized in that it is at least one of CaREY, REHY, and CREY. 4. The composition of claim 3, wherein the zeolite is REY containing about 11-22% by weight of rare earth metal ions. 5. Claims 1-4, wherein the binder is present in an amount of about 15-40% by weight of the catalyst.
The composition according to any of paragraphs. 6. A composition according to any one of claims 1 to 5, characterized in that it contains about 2 to 10 ppm of noble metal. 7. The composition according to claim 6, wherein the noble metal is impregnated onto the catalyst particles. 8. The composition according to claim 6, wherein the noble metal is impregnated onto a granular inorganic oxide carrier mixed with the catalyst. 9 (a) about 12 to 60% by weight rare earth metal exchanged zeolite; (b) optionally up to 75% by weight clay; and (c) an inorganic oxide binder, the zeolite, clay, and binder comprising: The agent is formulated into particles and further comprises: (d) 20-50% by weight alpha-alumina trihydrate; and (e) about 0.1-20 ppm platinum, palladium or mixtures thereof. In the method for producing a composition used as a catalyst for the decomposition of
A manufacturing process characterized in that the formulation is shaped into granules, the particles are then ion-exchanged with rare earth metals, and the precious metals are impregnated onto the zeolite-containing particles. 10 (a) about 12 to 60% by weight rare earth metal exchanged zeolite; (b) optionally up to 75% by weight clay; and (c) an inorganic oxide binder, the zeolite, clay, and binder comprising: The agent is formulated into particles and further comprises: (d) 20-50% by weight alpha-alumina trihydrate; and (e) about 0.1-20 ppm platinum, palladium or mixtures thereof. Components (c) and (d) and optionally component (b) are blended with component (a) as a zeolite in the form of a rare earth metal, A manufacturing method characterized in that the material is shaped into a granular form and the precious metal is impregnated onto the zeolite-containing particles.