CN116920934A - Preparation method of catalytic cracking auxiliary agent - Google Patents

Abstract

The invention discloses a preparation method of a catalytic cracking auxiliary agent, which specifically comprises the following steps: s1, adding part of phosphorus additive into an IMF structure molecular sieve and an MFI molecular sieve to prepare mixed slurry; s2, mixing the slurry, the metal modified aluminum stone, other inorganic binders and clay slurry, pulping, and spray drying; s3, after spray drying and forming, introducing the rest phosphorus additive; s4, drying and roasting. The phosphorus additive is a compound of phosphorus and can be one or more of phosphorus oxide, phosphoric acid, orthophosphate, phosphite, hypophosphite, basic phosphate, acid phosphate and organic compound containing phosphorus. The catalyst is used in catalytic cracking process, and can raise the yield and selectivity of propylene and butene effectively.

Description

Preparation method of catalytic cracking auxiliary agent

Technical Field

The invention belongs to the field of material preparation, and particularly relates to a preparation method of a catalytic cracking auxiliary agent.

Background

The function of the multi-production low-carbon olefin auxiliary agent is to increase the yield of low-carbon olefin, especially propylene, in the catalytic cracking process. The most commonly used active component is ZSM-5 molecular sieve. The cracking catalyst for producing light olefin consists of clay in 0-70 wt%, inorganic oxide in 5-99 wt% and zeolite in 1-50 wt%. Wherein the zeolite is a mixture of 0 to 25% by weight of REY or high silicon Y-type zeolite and 75 to 100% by weight of five-membered ring high silicon zeolite containing phosphorus and rare earth. The catalyst has higher hydrothermal activity stability, conversion rate and C2-C4 yield than the catalyst taking ZSM-5 zeolite as an active component.

The prior art also discloses a cracking catalyst of the phosphorus-containing modified ZSM-5 zeolite. The preparation method of the phosphorus-modified ZSM-5 comprises dispersing zeolite in an aqueous solution of phosphorus-containing compound with a pH value of above 4.5, and loading the zeolite with at least 10 wt% of phosphorus (P ₂ O ₅ Meter), then pulping with the matrix and other zeolite components, spray drying and shaping. The obtained catalyst has higher low-carbon olefin yield. A catalyst having a high zeolite content and high attrition resistance is also disclosed. The catalyst contains ZSM-5 zeolite in 30-85 wt% and phosphorus (P in 6-24 wt% ₂ O ₅ Calculated as) and less than 10 wt.% Al ₂ O ₃ And the marginClay, and the like, wherein phosphorus is present in the matrix. The catalyst is used in catalytic cracking process to increase the yield of light olefin, especially propylene.

However, the biggest weakness of such ZSM-5 molecular sieves is their poor activity stability and susceptibility to deactivation under the harsh periodic regeneration conditions of the FCC unit.

The IM-5 molecular sieve is an IMF structure molecular sieve, and is synthesized by Benazzi in 1998 for the first time. The resolution of structures was done by Baerlocher et al in 2007. The molecular sieve is a two-dimensional ten-membered ring channel structure, the channel diameter of the molecular sieve is similar to that of a ZSM-5 molecular sieve, and a limited channel exists in the third dimension. The catalyst has a pore structure similar to that of ZSM-5 molecular sieve, and has higher acid quantity and better hydrothermal stability, so that the catalyst is special in a plurality of catalytic reactions. A series of studies have been conducted on the catalytic performance of IM-5 molecular sieves by Corma et al, which have been found to be higher than ZSM-5 molecular sieves in terms of alkane cracking capacity.

In order to improve the protection molecular sieve and the selectivity of the low-carbon olefin, the matrix is often modified. The invention adopts molecular sieves with two structures, matches matrix and catalyst modification technology, provides a catalytic cracking auxiliary agent for increasing the concentration of low-carbon olefin, improves the concentration of low-carbon olefin in liquefied gas, and reduces dry gas and coke.

Disclosure of Invention

In order to solve the technical problems, the invention provides a catalytic cracking catalyst auxiliary agent and a preparation method thereof.

The invention provides a catalytic cracking auxiliary agent, which comprises an IMF structure molecular sieve, an MFI molecular sieve, metal modified aluminum stone, a phosphorus additive, other inorganic binders and clay; based on the dry weight of the auxiliary agent,

the IMF structure molecular sieve and the MFI molecular sieve account for 10-75 wt%;

3-20% by weight of metal-modified aluminite, wherein the metal in the metal-modified aluminite is 1-30% by weight of the aluminite in terms of oxide;

the phosphorus additive accounts for 3-35 wt%;

3-20 wt% of other inorganic binders;

clay comprises 0-60 wt%;

in the auxiliary agent ²⁷ In Al MAS NMR, the ratio of the resonance signal peak area with a chemical shift of 40+ -5 ppm to the resonance signal peak area with a chemical shift of 54 ppm+ -3 ppm is 0.1-1.

According to one embodiment of the invention, the preparation method of the metal modified aluminum stone comprises the following steps:

(1) Adding the aluminum stone into the cation-removing water for pulping; the slurry solids content is preferably 8 to 15 wt%;

(2) Selecting acid salts of metals for dissolution;

(3) Directly adding metal salts into the aluminum stone to acidify the aluminum stone;

(4) With or without hydrochloric acid, the final colloid is controlled to have a pH < 4, preferably a pH of 1.5-3.

According to an embodiment of the present invention, the metal is selected from at least one of IB, IIB, IV B and VIII B; preferably, the metal is selected from one or more of Fe, zr and Cu;

the metal salt is at least one selected from chloride, nitrate and sulfate.

According to one embodiment of the invention, the phosphorus additive is added in two steps.

According to an embodiment of the present invention, the phosphorus additive is a phosphorus compound, preferably, the phosphorus additive is one or more of phosphorus oxide, phosphoric acid, orthophosphate, phosphite, hypophosphite, basic phosphate, acid phosphate, and organic compound containing phosphorus; preferably, the phosphorus additive is one or more of phosphoric acid, ammonium phosphate, monoammonium phosphate, diammonium phosphate, and aluminum phosphate; more preferably, the phosphorus additive is diammonium phosphate.

According to an embodiment of the present invention, the mass ratio of the IMF structure molecular sieve to the MFI molecular sieve is 0.01 to 100, preferably 0.1 to 30, and more preferably 0.5 to 9.

According to an embodiment of the invention, the IMF structure molecular sieve is one or more selected from hydrogen-type IM-5, phosphorus-containing IM-5 and phosphorus-containing and transition metal IM-5 molecular sieves; the MFI molecular sieve is selected from one or more of hydrogen-type MFI molecular sieve, phosphorus-type MFI molecular sieve and transition metal MFI molecular sieve.

According to an embodiment of the present invention, the clay is at least one selected from the group consisting of kaolin, sepiolite, attapulgite, rectorite, montmorillonite and diatomaceous earth.

According to an embodiment of the present invention, the other inorganic binder is at least one selected from the group consisting of aluminum sol, silica alumina sol and silica sol.

The invention provides a preparation method of the auxiliary agent, which specifically comprises the following steps:

s1, preparing mixed slurry by adding part of phosphorus additive into the IMF structure molecular sieve and the MFI molecular sieve;

s2, mixing the slurry, the metal modified aluminum stone, the other inorganic binders and the clay slurry, pulping, and spray drying;

s3, after spray drying and forming, introducing the rest phosphorus additive;

s4, drying and roasting.

According to an embodiment of the invention, the drying temperature is from room temperature to 400 ℃, preferably from 100 to 300 ℃; the calcination temperature is 400-700 ℃, and the calcination time is 0.5-100 hours, preferably 0.5-10 hours.

According to one embodiment of the invention, the auxiliary agent is added with 1 to 10 weight percent of phosphorus additive before spraying and 2.1 to 24 weight percent after spraying.

The phosphorus additive after spraying is introduced in the following way: at least one phosphorus-containing compound selected from phosphoric acid, ammonium hydrogen phosphate, ammonium dihydrogen phosphate and ammonium phosphate is impregnated into the catalyst microspheres and/or chemisorbed with the phosphorus compound, and is introduced through solid-liquid separation (if necessary), drying and roasting processes.

In the obtained auxiliary agent, the phosphorus additive added before spraying exists in the form of phosphorus compounds (such as phosphorus oxides, orthophosphates, phosphites, basic phosphates and acid phosphates). The phosphorus additive may be present at any possible location of the adjunct, such as inside the pores of the zeolite, on the surface of the zeolite, and in the matrix material; the phosphorus compounds introduced after spraying are mainly present in the matrix material. The types of phosphorus additives added before and after spraying may be the same or different.

By passing through ²⁷ Al MAS NMR characterizes the coordination state of the auxiliary Al, and the ratio of the resonance signal peak area with the chemical shift of 40+/-5 ppm to the resonance signal peak area with the chemical shift of 54+/-3 ppm is 0.1-1. In 27 AlMASBMR, a four-coordination framework aluminum species with a chemical shift of 54+/-3 ppm is characterized by a resonance signal, a framework aluminum species coordinated with phosphorus is characterized by a resonance signal with a chemical shift of 40+/-3 ppm, and the characterization result shows that the action of phosphorus and molecular sieve framework aluminum can be reduced by adopting two steps of adding phosphorus additives.

And the two-step addition of the phosphorus additive also reduces the effect of phosphorus and matrix Al.

The invention provides a catalytic cracking catalyst which comprises the auxiliary agent or the auxiliary agent obtained by adopting the preparation method.

The invention provides a preparation method of metal modified aluminum stone, which comprises the following steps:

(1) Adding the aluminum stone into the cation-removing water for pulping; the slurry solids content is preferably 8 to 15 wt%;

(2) Selecting acid salts of metals for dissolution; the method comprises the steps of carrying out a first treatment on the surface of the

(3) Directly adding metal salts into the aluminum stone to acidify the aluminum stone;

(4) With or without hydrochloric acid, the final colloid is controlled to have a pH < 4, preferably a pH of 1.5 to 3.

Compared with conventional acidified bauxite. The metal modified aluminum stone prepared by the method reduces the use amount of hydrochloric acid, and is beneficial to improving the activity and stability of the catalytic auxiliary agent. The beneficial effects are that: the phosphorus additive and the metal modified aluminum stone are added in two steps, so that the selectivity of the catalyst for the low-carbon olefin is improved, and the catalyst is added in two steps, so that the effect of phosphorus and a matrix AL is reduced, and the effects of reducing dry gas and coke are achieved; the catalytic cracking auxiliary agent provided by the invention is used in the catalytic cracking process, and can effectively improve the yield and selectivity of propylene and butene through the synergistic effect of the components.

According to the preparation method of the metal modified aluminum stone, the metal salt solution is adopted to acidize the aluminum stone, so that the metal modified aluminum stone with good performance can be obtained, can be used as a catalytic cracking catalyst matrix, can improve low-carbon olefin, and can be used as other catalyst carriers.

Detailed Description

The following describes specific embodiments of the present disclosure in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the disclosure, are not intended to limit the disclosure.

The method for introducing the phosphorus additive after spraying comprises the following steps: the catalyst microspheres are impregnated with at least one phosphorus-containing compound selected from phosphoric acid, ammonium hydrogen phosphate, monoammonium phosphate and ammonium phosphate and/or chemisorbed with the phosphorus compound, and introduced through solid-liquid separation (if necessary), drying and calcination processes, wherein the drying temperature may be from room temperature to 400 ℃, preferably from 100 to 300 ℃, the calcination temperature may be from 400 to 700 ℃, preferably from 450 to 650 ℃, and the calcination time may be from 0.5 to 100 hours, preferably from 0.5 to 10 hours.

The preparation method of the catalytic cracking auxiliary agent provided by the disclosure comprises the steps of pulping an IMF structure molecular sieve and an MFI molecular sieve, and counting a part of phosphorus additive; the inorganic binder, clay and molecular sieve slurry are mixed, pulped, the feeding sequence is not specially required, preferably, clay and molecular sieve slurry are mixed first, and then mixed and pulped with metal modified aluminum stones and other inorganic binders, so that the activity and strength of the auxiliary agent are improved.

The preparation method of the catalytic cracking auxiliary agent further comprises the step of spray drying the slurry obtained by pulping. Methods of spray drying are well known to those skilled in the art and are not particularly required by the present disclosure.

The catalytic cracking auxiliary agent provided by the disclosure is suitable for catalytic cracking of various hydrocarbon oils. When used in the catalytic cracking process, the catalyst can be added into a catalytic cracking reactor independently or mixed with a catalytic cracking catalyst for use. Typically, the adjuvants provided by the present disclosure comprise no more than 30 wt%, preferably from 1 to 25 wt%, more preferably from 3 to 15 wt%, of the total amount of FCC catalyst and adjuvant mixture provided by the present disclosure, and the hydrocarbon oil is selected from one or more of various petroleum fractions, such as crude oil, atmospheric resid, vacuum resid, atmospheric wax oil, vacuum wax oil, straight run wax oil, propane light/heavy deoiling, coker wax oil, and coal liquefaction products.

The catalytic cracking aid provided by the disclosure is used in a catalytic cracking process, and the hydrocarbon oil catalytic cracking conditions can be conventional catalytic cracking conditions. In general, the hydrocarbon oil catalytic cracking conditions include a reaction temperature of 400 to 600 ℃, preferably 450 to 550 ℃, and a weight hourly space velocity of 8 to 120 hours ^-1 Preferably 8-80 hours ^-1 The ratio of the agent to the oil (weight ratio) is 1-20, preferably 3-15. The catalytic cracking aid provided by the present disclosure can be used in various existing catalytic cracking reactors, such as fixed bed reactors, fluidized bed reactors, riser reactors, multi-reaction zone reactors, and the like.

The present disclosure is further illustrated by the following examples, which are not intended to be limiting in any way, and the instruments and reagents employed in the examples of the present disclosure, unless otherwise indicated, are those commonly used by those of skill in the art.

The adjuvants of the present disclosure, when used for catalytic cracking reaction performance evaluation, were evaluated using an ACE unit.

The RIPP standard method disclosed in the present disclosure can be found in petrochemical analysis method, yang Cuiding et al, 1990 edition.

Some of the raw materials used in the examples were as follows:

pseudo-boehmite is an industrial product produced by Shandong aluminum company, and has a solid content of 60 weight percent;

the aluminum sol is an industrial product produced by the middle petrochemical catalyst Qilu division company, al ₂ O ₃ The content was 21.5 wt%;

the kaolin is special for the catalytic cracking catalyst produced by Suzhou kaolin company, and the solid content is 78 weight percent.

Hydrochloric acid: the chemical purity is 36-38 wt% and the concentration is produced by Beijing chemical plant.

ZRP-5, qilu division of China petrochemical catalystIndustrial product, P ₂ O ₅ The content is 4.12 percent, and the crystallinity is 75 percent

P-IM-5: soaking H-IM-5 molecular sieve in 0.2mol/L ammonium dihydrogen phosphate solution under stirring for two hr, drying at 120deg.C for 10 hr, and roasting at 500deg.C for 3 hr to obtain phosphorus modified IM-5 molecular sieve P-IM-5, wherein the phosphorus modified IM-5 has a concentration of 0.2mol/L ₂ O ₅ The content was 4.23 mass% and the crystallinity was 78%.

Metal modified alachlore example 1:

adding the aluminum stone into the deionized water, and pulping for 10min; feCl is taken ₃ Dissolving, and measuring PH=2; feCl is added ₃ Directly adding the solution into the aluminum stone to acidify the aluminum stone; finally, hydrochloric acid is added to a peptization state, and finally, the PH=3 of the colloid is controlled to obtain MAL-1;

metal modified alachlore example 2:

adding the aluminum stone into the deionized water, and pulping for 10min; taking ZrOCl ₂ Dissolving, and measuring PH=1; zrOCl ₂ Directly adding the solution into the aluminum stone to acidify the aluminum stone, and controlling the final colloid PH=2.5 and MAL-2;

metal modified alachlore example 3:

adding the aluminum stone into the deionized water, and pulping for 10min; cuCl is taken ₂ Dissolution, ph=1.5; cuCl is added ₂ The solution was directly added to the alachlore to acidify the alachlore, and finally hydrochloric acid was added to the peptized state, and the final colloid ph=2.5, mal-3 was controlled.

Catalyst example 1:

(1) Taking molecular sieves P-IM-5 and ZRP-5, adding deionized water, pulping for 10min, adding diammonium hydrogen phosphate (a), pulping for 120 min to obtain molecular sieve slurry; adding kaolin, alumina sol and metal modified aluminum stone into deionized water, pulping for 20min, adding molecular sieve slurry under stirring, adding hydrochloric acid to adjust the pH value of the slurry to 3.0, pulping for 45 min, and spray drying the obtained slurry to obtain microspheres.

(2) According to the saturated impregnation method, the water absorption of the microspheres is measured, the residual diammonium hydrogen phosphate (b) is dissolved by water, then the solution is slowly added into the microspheres, the solution is stirred uniformly, is kept stand for 4 hours at normal temperature, and is roasted for 2 hours at 500 ℃ to obtain CAT-1, and the proportion is shown in Table 2.

Examples 2 to 5: the procedure of example 1 is followed, and the specific proportions are shown in Table 2.

Comparative example 1:

(1) Taking a molecular sieve ZRP-5, kaolin and aluminum stone, adding decationized water and aluminum sol, pulping for 120 minutes, adding hydrochloric acid to adjust the pH value of the slurry to 3.0, then continuously pulping for 45 minutes, and spray-drying the obtained slurry to obtain microspheres;

(2) According to the saturated impregnation method, the water absorption of the microspheres is measured, the residual diammonium hydrogen phosphate is dissolved by water, then the solution is slowly added into the microspheres, the solution is stirred uniformly, the solution is kept stand for 4 hours at normal temperature, and the solution is roasted for 2 hours at 500 ℃ to prepare DCAT-2, wherein the proportion is shown in table 1.

TABLE 1

The following examples illustrate the cracking reaction effect of the cracking aid provided by the present invention using a fixed fluidized bed reactor.

The catalytic cracking catalysts SLA and 30 g of CAT-1 to 5 and DCAT1 to 5 were each subjected to an aging treatment at 800℃under a 100% steam atmosphere for 17 hours. Different amounts of the aged catalyst were mixed with SLA (main properties are shown in Table 2) and the catalyst mixture was charged into a reactor of a small fixed fluidized bed reactor to catalytically crack the raw oil shown in Table 3. The reaction conditions and the reaction results used are given in Table 4.

TABLE 2 SLA Primary Properties

Table 3 evaluation of raw oil Properties

Table 4 evaluation results

As can be seen from Table 4, compared with the reference auxiliary agent, the catalytic auxiliary agent provided by the invention can effectively increase the yield of the catalytic cracking liquefied gas, remarkably improve the concentration of propylene and butylene in the catalytic cracking liquefied gas, greatly improve the selectivity of low-carbon olefin and simultaneously reduce dry gas and coke.

Claims (14)

1. A catalytic cracking aid comprising IMF structured molecular sieves and MFI molecular sieves, metal modified alachlores, phosphorus additives, other inorganic binders and clays; based on the dry weight of the auxiliary agent,

the IMF structure molecular sieve and the MFI molecular sieve account for 10-75 wt%;

3-20% by weight of metal-modified aluminite, wherein the metal in the metal-modified aluminite is 1-30% by weight of the aluminite in terms of oxide;

the phosphorus additive accounts for 3-35 wt%;

3-20 wt% of other inorganic binders;

the clay accounts for 0-60 wt%.

2. The auxiliary agent according to claim 1, wherein the preparation method of the metal modified aluminum stone comprises the following steps:

(1) Adding the aluminum stone into the cation-removing water for pulping; the slurry solids content is preferably 8 to 15 wt%;

(2) Selecting acid salts of metals for dissolution;

(3) Directly adding metal salts into the aluminum stone to acidify the aluminum stone;

(4) With or without hydrochloric acid, the final colloid is controlled to have a pH < 4, preferably a pH of 1.5-3.

3. The adjuvant of claim 2 wherein the metal is selected from at least one of IB, IIB, IV B and VIII B; preferably, the metal is selected from one or more of Fe, zr and Cu;

the metal salt is at least one selected from chloride, nitrate and sulfate.

4. A promoter according to any one of claims 1-3, characterized in that the phosphorus additive is added in two steps.

5. The adjuvant according to any one of claims 1-4, wherein the phosphorus additive is a phosphorus compound, preferably the phosphorus additive is one or more of phosphorus oxides, phosphoric acid, orthophosphates, phosphites, hypophosphites, basic phosphates, acid phosphates, and phosphorus-containing organic compounds; preferably, the phosphorus additive is one or more of phosphoric acid, ammonium phosphate, monoammonium phosphate, diammonium phosphate, and aluminum phosphate; more preferably, the phosphorus additive is diammonium phosphate.

6. The auxiliary agent according to any one of claims 1 to 5, wherein the mass ratio of IMF structure molecular sieve to MFI molecular sieve is 0.01 to 100, preferably 0.1 to 30, further preferably 0.5 to 9.

7. The adjuvant according to any one of claims 1 to 6, wherein the IMF structure molecular sieve is one or more selected from the group consisting of hydrogen-form IM-5, phosphorus-containing IM-5 and phosphorus-containing and transition metal IM-5 molecular sieves; the MFI molecular sieve is selected from one or more of hydrogen-type MFI molecular sieve, phosphorus-type MFI molecular sieve and transition metal MFI molecular sieve.

8. The auxiliary agent according to any one of claims 1 to 7, wherein the clay is at least one selected from the group consisting of kaolin, sepiolite, attapulgite, rectorite, montmorillonite and diatomaceous earth.

9. The auxiliary agent according to any one of claims 1 to 8, wherein the other inorganic binder is at least one selected from the group consisting of an aluminum sol, a silica alumina sol and a silica sol.

10. The process for the preparation of an adjuvant according to any one of claims 1 to 9, characterized in that it comprises in particular the following steps:

s1, preparing mixed slurry by adding part of phosphorus additive into the IMF structure molecular sieve and the MFI molecular sieve;

s2, mixing the slurry, the metal modified aluminum stone, the other inorganic binders and the clay slurry, pulping, and spray drying;

s3, after spray drying and forming, introducing the rest phosphorus additive;

s4, drying and roasting.

11. The method of preparation according to claim 10, wherein the drying temperature is from room temperature to 400 ℃, preferably 100-300 ℃; the calcination temperature is 400-700 ℃, and the calcination time is 0.5-100 hours, preferably 0.5-10 hours.

12. The preparation method according to claim 10 or 11, wherein the phosphorus additive is added before spraying of the auxiliary agent in an amount of 1 to 10 wt% and is added after spraying in an amount of 2.1 to 24 wt%.

13. A catalytic cracking catalyst comprising the promoter of any one of claims 1 to 9 or prepared according to the preparation method of any one of claims 10 to 12.

14. A preparation method of metal modified aluminum stone comprises the following steps:

(1) Adding the aluminum stone into the cation-removing water for pulping; the slurry solids content is preferably 8 to 15 wt%;

(2) Selecting acid salts of metals for dissolution; the method comprises the steps of carrying out a first treatment on the surface of the

(3) Directly adding metal salts into the aluminum stone to acidify the aluminum stone;

(4) With or without hydrochloric acid, the final colloid is controlled to have a pH < 4, preferably a pH of 1.5-3.