CN1055105C - Cracking catalyst for high yield of isobutene and isopentene - Google Patents

Abstract

The present invention relates to a cracking catalyst for increasing isobutene yield and isopentene yield, which is prepared from three zeolite active constituents and a carrier (measured by the catalyst as the reference), wherein the three zeolite active constituents comprise 6 to 30 wt% of five-membered ring high-silicon zeolite containing phosphorus and rare earth, 5 to 20 wt% of USY zeolite and 1 to 5 wt% of beta-zeolite; 30 to 60 wt% of clay and 15 to 30 wt% of inorganic oxide are also contained. The preparation method of the cracking catalyst comprises: the catalyst product is obtained after homogenized molecular sieve slurry is added into carrier slurry, pulped, filtered, dried and formed. The catalyst has the characteristics of isobutene yield increase and isopentene yield increase under the technological conditions of catalytic cracking, and simultaneously, the catalyst can be used for concurrently producing high-octane gasoline.

Description

A Cracking Catalyst Producing Isobutene and Isoamylene

The present invention relates to a cracking catalyst, in particular to a cracking catalyst prolific in producing isobutene and isopentene.

In recent years, with the development of the automobile industry, the environmental pollution caused by automobile exhaust has attracted more and more attention. The United States and western industrialized countries have successively issued lead restrictions and clean air regulations to limit the content of benzene, aromatic hydrocarbons and harmful volatiles in automobile exhaust that are harmful to human health, which requires automobile manufacturers to strive to improve the control of emissions At the same time, it also requires petrochemical complexes and major companies to produce reformulated gasoline. At present, countries such as Europe and the United States use the method of adding MIBE, TAME and other ethers to gasoline to reduce the content of pollutants in automobile emissions. Therefore, the demand for isobutylene and isopentene, which are raw materials for MIBE and TAME, will also increase day by day. In petrochemical complexes, catalytic cracking technology is not only an important means to provide light oil, but also a basic organic chemical raw material for olefins. a way. USP3758403 reported that adding ZSM-5 to Y-type molecular sieve catalyst can increase the octane number of gasoline and also increase the yield of C ₃ -C ₅ olefins, but the increase is not large. CN1043520A also discloses a cracking catalyst for the production of light olefins, mainly used for the production of propylene and butene. The catalyst contains 75-100% by weight of ZSM-5 and 0-25% by weight of Y-type zeolite.

In addition, USP4911823 describes a catalyst containing beta zeolite for cracking high alkane content hydrocarbon oil with a wax content of at least 20% by weight, the content of beta zeolite in the catalyst is 5-95% by weight, and the rest is bonded agent, other zeolites, such as ZSM-5 or Y-type zeolite, can also be added, but the amount of other zeolites added should be less than that of β zeolite. This method can obtain gasoline with high octane number and increase the output of isobutene.

According to NPRA AM-91-34 and AM-92-43 reports, Grace Company uses a K value of 11.5 and a distillation range of 215-556 °C in the West Coast refinery of the United States with high nitrogen content feedstock. On the FCC unit, at 521 ℃, when using the RFG catalyst to carry out the catalytic cracking reaction, when the conversion rate is 68% by weight, the gasoline yield is 37.4 to 41.3% by weight, and the yields of isobutene and isopentene relative to the feedstock are respectively 3.8 to 4.0% by weight and 4.7 to 5.1% by weight. % by weight, the sum of the two is 8.5-9.1 % by weight, the gasoline octane number MON is 81.2-81.5, and the RON is 96.4-97.2. This document also reports that RFG is a newly developed catalyst containing non-faujasite in a carrier, wherein the content of Al ₂ O ₃ is 25-35% by weight, and the content of Na ₂ O is 0.15-0.37% by weight.

NPRA AM-92-45 reported that Engelhard Company used American Midland gas oil as a raw material, and evaluated the IsoPlus series catalysts on the micro-transverse (MAT) device. When the conversion rate was 70% by weight, the isobutene production rate of the IsoPlus-2100 catalyst The isobutene yield of the IsoPlus-2000 catalyst is 1.84 wt%. The gasoline product obtained from the medium-sized plant was also analyzed, and it was found that the yield of isopentene of IsoPlus-2000 was 4.5% by weight. But this document does not report the components and content of IsoPlus series catalysts.

CN 1103105A discloses a kind of cracking catalyst of prolific isobutene and isopentene recently, and this catalyst is made up of four kinds of active components and carrier, and each active component content is the modified HZSM5 that silicon-aluminum ratio is 20-100 5-25% by weight, 1-5% by weight of high-silicon HZSM5 with a silicon-aluminum ratio of 250-450, 5-20% by weight of USP zeolite, 1-5% by weight of zeolite beta, and the balance as a carrier. The catalyst is used for FCC On the device, use naphthenic mid-base straight-run wax oil with a K value of 11.56. When the conversion rate is 72-80% by weight, the yield of gasoline is 36.84-45.09% by weight, the yields of isobutene and isopentene are 4.33-4.84% by weight and 4.68-5.77% by weight respectively, and the sum of the two is 9.38-45.09% by weight. 10.49% by weight, the gasoline octane number MON is 81.2-82.0, RON is 93.9-94.6.

The object of the present invention is to provide a catalytic cracking catalyst, which can produce more isobutene and isopentene while ensuring the production of the main target product gasoline.

Catalyst of the present invention has adopted the five-membered ring silicalite containing phosphorus and rare earth, thereby has high isobutylene and isopentene productive rate, and the specific composition of catalyst of the present invention is as follows: (based on catalyst, weight %)

(1) Five-membered ring silicalite containing phosphorus and rare earth 6～30

(2) USY zeolite 5～20

(3) Beta zeolite 1～5

(4) Clay 30～60

(5) Inorganic oxides 15～30

The five-membered ring silicalite containing phosphorus and rare earth is the five-membered ring silicalite containing rare earth after being treated with aluminum phosphate, and the phosphorus (calculated as P ₂ O ₅ ) in the zeolite is 2-20% by weight, Preferably 2-10% by weight, containing 2-10% by weight of rare earth (calculated as RE ₂ O ₃ ).

The rare earth-containing five-membered ring silicalite (trade name ZRP) has an X-ray diffraction spectrum of the ZSM-5 zeolite family, and its anhydrous chemical composition expression is: 0.01～0.30RE ₂ O ₃ ·0.4～1.0 Na ₂ O·Al ₂ O ₃ ·20～60 SiO ₂ , the rare earth in this composition comes from the rare earth-containing faujasite zeolite seed used in the synthesis. The ratio of the adsorption amount of hexane is 2-4 times that of ZSM-5 zeolite. The zeolite is prepared by the method disclosed in CN1058382A or USP5232675, that is, water glass, aluminum phosphate, inorganic acid are used as raw materials, REY or REHY zeolite is used as a crystal seed, and the crystallization reaction is carried out at 130-200 ° C. 12-16 hours made.

The method of treating ZRP zeolite with aluminum enoate is as follows: the zeolite is pre-exchanged with ammonium ions to reduce the sodium content (calculated as Na ₂ O) to no more than 0.1% by weight, and the composition is Al ₂ O ₃ : P ₂ O ₅ = 1:1~3 aluminum phosphate colloid is mixed evenly with the zeolite according to the weight ratio of P ₂ O ₅ :zeolite (dry basis) = 1:5~99, and exists at 300~600°C and 10~100% water vapor Lower roasting for 0.5 to 6 hours.

The preparation method of the catalyst of the present invention is: adding the homogeneous molecular sieve slurry to the carrier slurry, beating, filtering, drying, and molding to obtain a catalyst product. The specific steps are:

(1) Mix and beat natural clay and deionized water for 0.5-1 hour, then add hydrochloric acid to acidify, then add pseudo-boehmite and stir evenly, heat up to 55-60°C, and age for 0.50-1 hour to obtain a solid content of 15-25% by weight of carrier slurry, wherein the addition of hydrochloric acid accounts _for 15-30% by weight of the _Al2O3 content in pseudo-boehmite;

(2) Mix the five-membered ring silicalite, USP and beta zeolite containing phosphorus and rare earth evenly, then add deionized water to beat and homogenize to obtain a molecular sieve slurry with a solid content of 20 to 40% by weight;

(3) Adding the molecular sieve slurry to the carrier slurry, beating, filtering, drying and forming.

The catalyst of the invention is suitable for producing isobutene and isopentene from paraffin base, naphthenic base and intermediate base wax oil and blended residual oil raw materials. When the catalyst of the invention is used for the catalytic cracking reaction, while producing more isobutene and isopentene, it can also co-produce high-octane gasoline.

The catalyst of the present invention uses three active components to prepare the cracking catalyst, and has higher yields of isobutylene and isopentene than the catalyst using four active components disclosed in CN1103105A. As on the FCC device, using the same feed oil (K value 11.56) and operating conditions (reaction temperature 520 ° C), using the catalyst of the present invention, the yields of isobutene and isopentene are 4.55-5.08% by weight, 4.77- 5.89% by weight, the sum of the two is 9.71-10.84% by weight, and the yields of the three items are respectively increased by about 5.0%, 2.0% and 3.4%. Obviously, compared with the RFG catalyst of Grace Company, the catalyst of the present invention also has higher yields of isobutylene and isopentene.

The present invention is further illustrated below by examples.

The five-membered ring silicalite (hereinafter referred to as P-ZRP) containing phosphorus and rare earth used in the example is prepared as follows: get 100 grams (dry basis) ZRP zeolite (product of Shandong Zhoucun Catalyst Factory, SiO ₂ /Al ₂ O ₃ 30 , RE ₂ O ₃ 2.0%), according to the weight ratio of zeolite (dry basis): ammonium sulfate: decationized water = 100:25:2000, ion exchange was performed at 90° C. for 1 hour, and then exchanged once after filtration. The sodium content (calculated as Na ₂ O) in the zeolite is 0.04% as measured by atomic absorption spectroscopy. Mix 13.8 grams of pseudo-boehmite (product of Shandong Aluminum Factory, Al ₂ O ₃ 95%, solid content 30%), 9.0 grams of industrial phosphoric acid (content 85%) and 200 grams of decationized water, and then add the above-mentioned ammonium exchange to obtain In the zeolite, stir evenly, after _drying at 110°C, aging in 800°C, 100% water vapor chlorine for 4 hours to obtain a five-membered ring with a phosphorus content (calculated as _P2O5 ) of 5% Silica zeolite P-ZRP.

Analytical test methods used in the examples:

1. Al ₂ O ₃ , Fe ₂ O ₃ : X-ray fluorescence spectrometry;

2. Na ₂ O: plasma spectrometry (ICP);

3. Specific surface and pore volume: N ₂ adsorption method;

4. Carbon residue: electric furnace method;

5. Gasoline octane number: Chromatography.

Manufacturers and specifications of raw materials used in examples

1. Hydrous kaolin: Suzhou China Clay Company, solid content 82.2% by weight;

2. Pseudoboehmite: Shandong Aluminum Plant, Al ₂ O ₃ content 32% by weight;

3. USP zeolite: Zhoucun Catalyst Factory, Na ₂ O<1% by weight;

4. Beta zeolite: Fushun Petrochemical Company No. 3 Petroleum Plant, silicon-aluminum ratio 26,

Na ⁺ <0.5% by weight;

5. Hydrochloric acid Beijing Organic Chemical Factory.

Instances 1 to 5

Take a predetermined amount of decationized water and halloysite, stir and beat for 1 hour, then add industrial hydrochloric acid to acidify, stir for 0.5 hours, then add pseudo-boehmite and stir evenly, raise the temperature to 55°C, and age for 1 hour to obtain the carrier slurry .

Mix P-ZRP, USY and zeolite beta (dry basis) evenly, add deionized water to make a slurry, and obtain a molecular sieve slurry after homogenization, add the homogenized molecular sieve slurry to the carrier slurry, beat, filter, shape, and dry Catalysts A to E were prepared. The amount of each component used in the preparation process is shown in Table 1, the composition of the catalyst product obtained is shown in Table 2, and the physical and chemical properties of catalysts A to E are shown in Table 3.

Table 1 example Catalyst number The amount of raw materials used to prepare the carrier, kg Prepare catalyst raw material consumption, kg water Kaolin hydrochloric acid Pseudoboehmite P-ZRP USY beta water 1 A 31 5.7 0.75 9.3 2.02 1.0 0.3 6 2 B 34 6.7 0.5 6.25 1.51 0.5 0.2 6 3 C 16 2.8 0.38 4.7 1.0 0.7 0.1 3 4 D. 17 3.3 0.25 3.1 0.8 0.4 0.1 3 5 E. 31 5.7 0.75 9.3 2.53 1.5 0.3 6

Example 6

In this example, catalysts A to E of the present invention are evaluated with a small fluidized bed device.

Evaluation conditions: catalyst particle size 20-100 microns (mainly 60-80 microns)

    Catalyst load 200 grams

  Reaction temperature 520°C

Weight airspeed 10h ^-1

      Reaction pressure   Normal pressure

The ratio of agent to oil 8.0

Before catalyst evaluation, high-temperature water vapor deactivation treatment was carried out in advance. The treatment conditions are: 790°C, normal pressure, 100% steam treatment for 10 hours, the raw material used is naphthenic intermediate base wax oil, its properties are shown in Table A, and the product distribution and olefin yield obtained from the evaluation are shown in Table 5 and Table 6 respectively . The conversion rate in Table 5 refers to the percentage of the weight of products except diesel oil and heavy oil to the weight of raw oil used.

As can be seen from Table 5 and Table 6, compared with the catalysts disclosed in the corresponding examples 1 to 5 in CN1103105A, on the FCC device, when using the same feedstock oil (K value 11.56) and operating conditions (reaction temperature 520 ° C) , the yields of isobutylene and isopentene of catalysts A to E of the present invention are 4.55-5.08% by weight and 4.77-5.89% by weight respectively, and the sum of the two is 9.71-10.84% by weight, corresponding to the above-mentioned Chinese patent examples 1-5 The three yields of the obtained catalyst increased by about 5.0%, 2.0% and 3.4% respectively. And the RFG catalyst announced by Grace company, its three productive rates are successively 3.8-4.0 weight %, 4.4-5.1 weight % and 8.5-9.1 weight %, obviously, the isobutylene and isopentene productive rate of catalyst A～E of the present invention are higher than It is high.

In addition, as can be seen from Table 6, when adopting the catalyst of the present invention to carry out the catalytic cracking reaction, while producing more isobutene and isopentene, it can also be combined with high-octane gasoline, and the motor octane number (MON) of the gasoline produced is It reaches 81.0-81.8, and the research octane number (RON) reaches 94.0-94.8.

Table 2

table 3

Table 4 Raw oil: naphthenic middle base straight run wax oil Density, g/ ^cm3 kinematic viscosity at 20°C, freezing point at 80°C ^mm2 /s, °C aniline point, °C carbon residue, wt% basic nitrogen, ppm refractive index, n _D ²⁰ carbon, wt% hydrogen, wt% sulfur, Weight % Nitrogen, Weight % Nickel, ppm Characteristic Factor Distillation Range, °C Initial Boiling Point 5% 10% 30% 50% 70% 90% 95% Dry Point 0.923014.413580.20.126901.495487.2212.270.190.210.3611.56241297325382411437470480510

table 5

Table 6

Claims (10)

1. a kind of cracking catalyst of prolific isobutene and isopentene is characterized in that this catalyst is made up of five-membered ring silicalite, USY zeolite, beta zeolite and carrier containing phosphorus and rare earth, and wherein carrier is made of clay and inorganic Oxide composition, this catalyst composition is as follows (based on catalyst, weight %):   Five-membered ring silicalite containing phosphorus and rare earth 6～30 USY zeolite 5～20 zeolite beta 1～5 Clay 30～60 Inorganic oxides 2. The catalyst according to claim 1, characterized in that the five-membered ring silicalite containing phosphorus and rare earth is 2-20% by weight of phosphorus (calculated as P ₂ O ₅ ) after aluminum phosphate treatment. A rare earth-containing five-membered ring silicalite. 3. The catalyst according to claim 1, characterized in that said five-membered ring silicalite containing phosphorus and rare earth is 2-10% by weight of phosphorus (calculated as _P2O5 ) obtained by treating with aluminum _phosphate A rare earth-containing five-membered ring silicalite. 4. The catalyst according to claim 2 or 3, characterized in that the rare earth-containing five-membered ring silicalite has an X-ray diffraction spectrum of the ZSM-5 zeolite family, and its anhydrous chemical expression is 0.01 to 0.30 RE ₂ O ₃ ·0.4～1.0 Na ₂ O·Al ₂ O ₃ ·20～60SiO ₂ , the ratio of the adsorption capacity of n-hexane to cyclohexane is 2-4 times that of ZSM-5 zeolite. 5. according to the described catalyzer of claim 2 or 3, it is characterized in that described rare earth-containing five-membered ring silicalite is to take water glass, aluminum phosphate, inorganic acid as raw material with REY or REHY zeolite as crystal seed, at 130 It is made by crystallization reaction at ~200°C for 12-60 hours. 6. according to the described catalyzer of claim 2 or 3, it is characterized in that the described method of processing the five-membered ring silicalite containing rare earth with aluminum phosphate is as follows: the zeolite is carried out pre-exchange treatment with ammonium ion to make its sodium content ( (calculated as Na ₂ O) is reduced to no more than 0.1% by weight, and the aluminum phosphate colloid with the composition Al ₂ O ₃ : _{P 2} O ₅ =1:1～3 is based on P ₂ O ₅ : zeolite (base)=1: The weight ratio of 5-99 is uniformly mixed with the zeolite, and calcined at 300-600 DEG C and 10-100% steam for 0.5-6 hours. 7. The catalyst according to claim 1, characterized in that said clay is kaolin or halloysite. 8. The catalyst according to claim 1, characterized in that said inorganic oxide is selected from alumina. 9. The catalyst according to claim 8, characterized in that the precursor of said alumina is pseudo-boehmite. 10. according to the described catalyzer of claim 1 or 9, it is characterized in that the preparation step of this catalyzer is (1) Mix the clay with deionized water and beat for 0.5-1 hour, acidify with hydrochloric acid, add pseudo-boehmite and stir evenly, heat up to 55-66°C and age for 0.5-1 hour to obtain a solid content of 15-25 wt. % of the carrier slurry, wherein the addition of hydrochloric acid accounts for 15 to 30% by weight of the Al ₂ O ₃ content in the pseudo-boehmite; (2) The mixture of rare earth-containing five-membered ring silicalite, USY zeolite and beta zeolite is beaten with deionized water and homogenized to obtain a molecular sieve slurry with a solid content of 20% to 40% by weight; (3) adding the molecular sieve slurry to the carrier slurry for beating, filtering, drying and forming.