WO2008095359A1

WO2008095359A1 - A recycling method for a fluidized bed microsphere catalyst

Info

Publication number: WO2008095359A1
Application number: PCT/CN2007/002319
Authority: WO
Inventors: Peng Tian; Zhongmin Liu; Lei Xu; Lixin Yang; Cuiyu Yuan; Zhihui Lv; Shuanghe Meng; Yue Qi; Changqing He; Yingxu Wei; Xiangao Wang
Original assignee: Dalian Institute Of Chemical Physics, Chinese Academy Of Sciences
Priority date: 2007-02-07
Filing date: 2007-08-01
Publication date: 2008-08-14
Also published as: CN101157051A; CN101157051B

Abstract

A recycling method for a fluidized bed microsphere catalyst, wherein mixing the catalysts to be recycled with the raw materials for preparation of fresh microsphere catalysts in certain proportion, glue milling the slurry, then spray drying and calcining under high temperature, then a microsphere catalyst having low abrasion index and suitable particle size distribution can be obtained. The method comprises the following steps: 1) mixing the catalysts to be recycled with virgin molecular sieve, binder, promoter, pore forming agent, and deionized water, based on the weight of dry oxides, pulping, the weight percent of the catalysts to be recycled not more than 80% of the total dry oxides of the mixtures; 2) glue milling the slurry by a glue mill to get the particle diameter of solid particles lower than 20μm, the particle diameter of 90% solid particles lower than 10μm, the particle diameter of 70% solid particles lower than 5μm; 3) spray drying to prepare a microsphere sample; 4) calcining the microsphere sample under 500-800° C in an oxygen containing atmosphere to obtain a fluidized bed microsphere catalyst. The prepared catalyst is suited for use in the conversion of oxygenates to olefins.

Description

Method for recovering microsphere catalyst for fluidized bed

Technical field

The present invention relates to a method for recovering a microsphere catalyst for a fluidized bed and a catalytic application of the recovered catalyst for the conversion of an oxide-containing olefin to an olefin. Background technique

Ethylene and propylene are important basic chemical raw materials. At present, China is mainly prepared by light oil cracking method. With the shortage of petroleum resources and rising prices, the technology for producing low-carbon olefins from non-oil routes is becoming more and more urgent. The research and development of ethylene and propylene has become a hot spot for domestic and foreign research institutions and international companies. The single-series, large-scale industrialization technology for natural gas or coal to produce methanol is very mature, so the research on the production of olefins (MTO) from methanol has become a key technology for the production of low-carbon olefins from non-oil routes.

The small pore phosphorus silica gel molecular sieve has better MTO catalytic performance, but has the characteristics of rapid carbon deposition in the fixed bed reaction process, thereby causing rapid deactivation and selective reduction of the catalyst, and cannot meet the requirements of industrial continuous production. Fluidized bed is a common form of reactor used in the chemical industry. The MTO process of a fluidized bed reactor with continuous reaction-regeneration can avoid the above problems. Catalysts suitable for use in fluidized bed reactors should be microspheres with a suitable strength and particle size distribution while maintaining high catalytic performance.

At present, a fluidized bed microsphere catalyst is prepared by a spray drying method. Generally, the microsphere catalyst is composed of an active component such as a molecular sieve and a binder, and the binder functions to disperse the active component and increase the strength of the catalyst. In addition, the presence of inactive components in the catalyst can also act to dilute the molecular sieve to reduce the heat of reaction. For example, USP 5,126,298 reports the preparation of a high-strength cracking catalyst which is prepared by spray drying two different clays, zeolite molecular sieves and phosphorus-containing compounds into a slurry having a pH of <3; USP 5248647 reports the molecular hoof of SAPO-34. A method for spray drying a slurry made of kaolin and silica sol; USP6153552 discloses a method for preparing a microsphere catalyst containing a SAPO molecular sieve, which is obtained by mixing SAPO molecular sieve, inorganic oxide sol, and phosphorus-containing compound by spray drying. USP6787501 reports spray-drying SAPO-34 molecular sieves, binders and matrix materials to catalysts for methanol conversion; CN01132533A reports the preparation of wear-resistant index catalysts for methanol conversion by reducing the quality of molecular sieves in the catalyst The content serves to increase the catalyst wear index.

When the catalyst is produced by spray drying, two different particle size distributions of coarse powder and fine powder are obtained at the same time. Product. The particle size distribution of the catalyst used in the fluidized bed is certain, and the coarse powder and the fine powder are generally mixed and formulated in proportion. If the catalyst is prepared at a different ratio than the ratio of coarse to fine in the production process, a portion of the catalyst will remain. Recycling the remaining catalyst not only causes a loss in production, but also increases production costs. In addition, the catalyst wears out in the circulating fluidized bed unit, and most of the powdered catalyst can be recovered by cyclone separation equipment. If these powdered catalysts still maintain the original excellent reaction performance, their recycling will also reduce the production cost of the catalyst, and have certain economic value.

Patent CN1516177A reports a method for reusing a molecular sieve-containing catalyst by mixing a molecular sieve microsphere catalyst with a large amount of deionized water, grinding to reduce the particle size of the particles in the slurry, and then re-spray drying to prepare a lower wear index. And a catalyst suitable for particle size distribution. It should be noted, however, that the catalyst used for recovery must be a fresh, uncalcined sample, i.e., the molecular sieve contains an organic templating agent. The method for preparing a fluidized bed microsphere catalyst by recycling a post-reaction catalyst (carbon-containing sample or calcined sample) has not been reported in the literature. Summary of the invention

The inventors' research work has shown that any catalyst that cannot be directly used in a fluidized bed reactor (wear index and morphology cannot meet the requirements), that is, fresh uncalcined catalyst, freshly calcined catalyst, post-reaction carbon-containing catalyst, and reaction Thereafter, the carbon-depleted catalyst is calcined, and the fluidized bed microsphere catalyst prepared to have a lower wear index and a suitable wear index is recycled. For a detailed preparation of the fresh microsphere catalyst for the conversion of oxygenates to olefins referred to in this patent, see our patent application (Application No. 200610089171.1).

One of the objects of the present invention is to provide a method for recovering a microsphere catalyst for a fluidized bed. In the method, the catalyst to be recovered is mixed with each raw material for preparing a fresh microsphere catalyst in a certain ratio, and the slurry is gel-milled, spray-dried and calcined at a high temperature to obtain a microsphere catalyst having a lower wear index and a suitable particle size distribution.

The above recovery method of the present invention is characterized in that the microsphere catalyst referred to is prepared by using SAPO/MeAPSO molecular sieve as an active component, adding a binder, an auxiliary agent and a pore former. The elemental composition (mass content) of the catalyst is 2 to 60% of silicon oxide, 8 to 50% of phosphorus oxide, 20 to 70% of alumina, 0 to 10% of alkaline earth metal oxide, 0 to 20% of transition metal oxide, and satisfy The sum of the total mass contents is 100%. Wherein, the indicated SAPO/MeAPSO molecular sieve is in the form of its original powder, that is, the molecular sieve contains the organic template introduced during the synthesis, and the pore diameter is less than 0.5 nm; the metal contained in the MeAPSO molecular sieve is titanium, vanadium, chromium, manganese, iron, a mixture of one or any of cobalt, nickel, copper, zinc, zirconium, etc.; the binder is kaolin; the auxiliary is one of oxides, inorganic salts or organic salts of calcium, barium, strontium and zirconium The mixture may be a mixture of one or more of phosphoric acid, diammonium hydrogen phosphate, ammonium hydrogen phosphate; the pore forming agent is an organic compound, preferably a natural product such as phthalocyanine powder. The invention is characterized in that the catalyst to be recovered may be a fresh microsphere catalyst (calcined or uncalcined sample), a reaction catalyst (carbon-containing or calcined carbon-removed sample), or a cyclone separation through a fluidized bed. The device recovers the obtained catalyst powder (carbon-containing or calcined carbon-removed sample). Among them, the content of the sub-sieve in the catalyst obtained by cyclone separation is similar to that of the fresh catalyst.

Specifically, the preparation process of the microsphere catalyst recovery method of the present invention comprising a molecular sieve as an active component is as follows:

1) mixing the catalyst to be recovered with molecular sieve raw powder, binder, adjuvant, pore forming agent and deionized water according to a certain oxide dry basis ratio, and beating;

2) The slurry is passed through a colloid mill, so that the solid particles contained therein have a diameter of less than 20 μm, 90% of the particles have a diameter smaller than ΙΟμπι, and 70% of the particles have a diameter of less than 5 μm _;

3) Spray drying using a pressure spray dryer or a centrifugal spray dryer to prepare a sample of the microspheres.

4) The microsphere sample is obtained by calcining the microsphere sample in a 500-80 atmosphere in an oxygen atmosphere.

Wherein, the recovered catalyst has an oxide dry basis content in the total furnish of not more than 80% by weight, preferably 10% to 80% by weight; the recovered catalyst and molecular sieve raw powder is SAPO/MeAPSO molecular sieve and is in the total batching The oxide dry basis content is 20-50% by weight _{; the} binder has an oxide dry basis content of 10 to 75% by weight in the total furnish _{; the} auxiliary agent has an oxide dry basis content of 0-30% by weight in the total furnish. The pore former (Tianjing powder) is contained in the total furnish in an amount of 0 to 2% by weight.

The invention is characterized in that the microsphere catalyst has an abrasion index of less than 2.

Another object of the present invention is to directly apply the above prepared microsphere catalyst to a circulating fluidized bed in which an oxygenate is converted to an olefin. Detailed ways

The invention is described in detail below by way of examples. Example 1

4.17 kg of silica sol (Si0 ₂ content of 30 wt%), 1.76 kg of kaolin (water content of 15 wt, SiO ₂ content of 53 wt% in the solid after burning, A1 ₂ 0 ₃ content of 45 wt%) and 1.81 kg of SAPO -34 molecular sieve raw powder (synthesized according to the patent CN1131845 method) and 2.5 kg of aluminum sol (A1 ₂ 0 ₃ content of 20% by weight) were sequentially added to 3.34 kg of deionized water and stirred. Add 1.09kg of calcium nitrate (CaO content 23wt%) to 2kg of deionized water, stir to dissolve, then add calcium nitrate solution to the previous mixed slurry, and finally add 20g The tianjing powder (infiltrated with a small amount of ethanol) was stirred for 30 min. The material liquid was subjected to rubber grinding by a colloid mill, so that the solid particle diameter of the finally obtained slurry was 70% less than 5 μm (the particle size distribution test was carried out by using a ΒΤ-9300 laser particle size distribution meter produced by Dandong Baite Instrument Co., Ltd.). The slurry was spray dried (centrifugal spray drying device). The obtained spray-dried product was designated as hydrazine, and the product was calcined in air at 650 ° C for 4 hours to obtain an oxygenate-converted olefin-forming catalyst, which was designated as MC. Example 2

The MC sample was industrially amplified by the method of Example 1, and used in a circulating fluidized bed for industrial testing (catalyst loading 4 tons, methanol treatment amount 50 tons/day), and methanol conversion to olefin reaction. After the device was operated smoothly for 30 days, the collected catalyst powder was taken out from the cyclone sampling port, which was recorded as XM. A small amount of catalyst sample was taken from the sampling port of the reactor and recorded as FM. Example 3

A portion of the XM and FM samples were taken and calcined in air at 650 ° C to remove the moisture and reactive carbon contained therein, and the obtained samples were designated as XMC and FMC, respectively. Example 4

4.22 kg of M sample, 1.25 kg of silica sol (Si0 ₂ content of 30 wt%), 0.53 kg of kaolin (water content of 15 wt%, SiO ₂ content of 53 wt% in the solid after burning, A1 ₂ 0 ₃ content of 45 wt %) and 0.54 kg of ZrAPSO-34 molecular sieve raw powder (synthesized according to the patent CN1111091 method) and 0.75 kg of aluminum sol (A1 ₂ 0 ₃ content of 20% by weight) were sequentially added to 8.05 kg of deionized water and stirred. 0.33 kg of calcium nitrate (CaO content 23 wt%) was added to 1 kg of deionized water, stirred and dissolved, then the calcium nitrate solution was added to the previous mixed slurry, and finally 2 g of tianjing powder (infiltrated with a small amount of ethanol) was added. Stir for 30 min. The material liquid was subjected to rubber grinding by a colloid mill, so that the solid particle diameter of the finally obtained slurry was 70% less than 5 μm (the particle size distribution test was carried out by using a ΒΤ-9300 laser particle size distribution meter produced by Dandong Baite Instrument Co., Ltd.). The slurry was spray dried (centrifugal spray drying device). The obtained spray-dried product is calcined in air at 650 ° C for 3 hours to obtain a microsphere catalyst, which is recorded as

Example 5

According to the proportion of the ingredients in the embodiment 4 and the preparation method, the M sample was respectively used for MC, XM, XMC, FM, The FMC sample was replaced by catalyst preparation. The obtained spray-dried product was calcined in air at 650 ° C for 3 hours to obtain a microsphere catalyst, which was designated as MC-1S, XM-1S, XMC-1S FM-1S, and FMC-1S, respectively. Example 6

1.81 kg of M sample, 2.33 kg of silica sol (Si0 ₂ content of 30 wt%), 1.24 kg of kaolin

(The moisture content is 15wt%, the content of SiO ₂ in the solid after burning 53%% and 2.11kg of SAPO-34 molecular sieve raw powder (according to the method of patent CN1131845, sequentially added to 9.18kg of deionized water, stirred. The grinding is performed by grinding, so that the diameter of the solid particles in the finally obtained slurry is 70% less than 5 μm (the particle size distribution test is carried out by using the ΒΤ-9300 laser particle size distribution meter produced by Dandong Baite Instrument Co., Ltd.). The slurry is spray dried (pressure type) Nebulizer device) The obtained spray-dried product was calcined in air at 650 ° C for 3 h to obtain a microsphere catalyst, which was designated as M-2S.

According to the proportion of the ingredients in the first embodiment and the preparation method, the SAPO-34 molecular sieve was replaced with a ZnAPSO-34 molecular sieve (synthesis method ZrAPSO-34 in the same manner as in Example 4) to prepare a microsphere catalyst. The obtained spray-dried product was designated as N, and calcined in air at 650 ° C for 3 hours to obtain a microsphere catalyst, which was designated as NC. Example 8

According to the proportion of the ingredients in the embodiment 6 and the preparation method, the M sample was replaced with MC, NC, XMC, FM, FMC samples, respectively, to prepare the catalyst. The obtained spray-dried product was calcined in air at 650 ° C for 3 hours to obtain microsphere catalysts, which were respectively recorded as MC-2S, NC-1S, XMC-2S, FM-2S, and FMC-2S. Example 9

The catalyst samples obtained in Examples 1, 4, 5, 6, 8 were subjected to wear index measurement, and the results are shown in Table 1. Several catalysts have a low wear index.

Abrasion Index Determination Method: Approximately 7 g of the catalyst sample was placed in a gooseneck having an inner diameter of about 2.5 cm, and humid air was passed through the tube at a flow rate of 20 min to provide a fluidized environment. The fine catalyst powder blown out from the catalyst was collected in a special filter bag and tested for 4 hours. The wear index is calculated as the mass percentage of the average amount of catalyst lost per hour of initial charge. Example 10

M Partial catalysts obtained in Examples 1 and 5 were subjected to methanol conversion to produce lower olefins (MTO)

II

Reaction evaluation.

II

Evaluation conditions: Weigh 10g sample into a fixed bed reactor, activated sample was first raised 550Ό half hour at 40ml / mi _n nitrogen, then cooled to 450'C chemical reaction. Nitrogen gas was stopped, fed with a micro pump, 40 wt% methanol aqueous solution, and the weight space velocity WHSV was 2.01^, and the reaction product was analyzed by on-line gas chromatography. The results are shown in Table 2.

Table 1 Wear Index Measurement of Microsphere Catalysts Sample MC M-1 MC-1 XM-1S M-2 MC-2 NC-1 FM-2S

S S S S S

Wear index 0.5 0.45 0.62 0.68 0.54 0.78 0.82 0.65 0.74

1

Table 2 Results of methanol conversion to olefins * Catalyst samples

Product distribution

MC M-1S MC-1S XM-1S FM-1S

CH ₄ 0.81 0.95 0.89 0.82 0.90

C ₂ H ₄ 46.04 47.58 46.04 46.57 46.90

C ₂ H ₆ 1.48 1.51 1.63 1.43 1.19

C ₃ H ₆ 41.47 40.35 41.66 40.35 40.52

C ₃ H ₈ 2.72 2.96 2.24 2.98 2.52

C ₄ + 5.74 5.16 5.51 6.12 6.24

C ₅ + 1.35 1.49 1.69 1.73 1.73 Conversion rate (%) 100.00 100.00 100.00 100 100.00

87.51 87.94 87.70 86.92 87.42

*The best reaction result when methanol is 100% converted

Claims

1. A method for recovering a microsphere catalyst for a fluidized bed, wherein the catalyst to be recovered is mixed with each raw material for preparing a fresh microsphere catalyst according to a certain ratio, and the slurry is subjected to spray drying, spray drying and high temperature baking, and the obtained catalyst can be obtained. A microsphere catalyst having a low wear index and a suitable particle size distribution; the preparation process is as follows:

1) mixing the catalyst to be recovered with molecular sieve raw powder, binder, auxiliary agent, pore former and deionized water, beating, and recovering the catalyst, the weight of the oxide dry base in the total batch is not more than 80% ;

Right

2) The slurry is passed through a colloid mill, so that the solid particles contained therein have a diameter of less than 20 μm, 90% of the particles have a diameter smaller than ΙΟμπι, and 70% of the particles have a diameter of less than 5 μm;

3) spray drying to prepare a sample of microspheres;

4) The microsphere sample is obtained by calcining the microsphere sample in an oxygen atmosphere at 500-800 ° C to obtain a fluidized bed microsphere catalyst.

begging

2. Process according to claim 1, characterized in that the catalyst recovered in step 1) has an oxide dry basis weight content of from 10 to 80% by weight in the total furnish.

3. Process according to claim 2, characterized in that the active component of the recovered catalyst in step 1) is a SAPO/MeAPSO molecular sieve.

4. Process according to claim 2, characterized in that the molecular sieve raw powder in step 1) is a SAPO/MeAPSO molecular sieve.

5. A method according to claim 1 wherein the binder in step 1) has an oxide dry basis content of from 10 to 75% by weight in the total furnish.

6. Process according to claim 1, characterized in that in the step 1) the auxiliaries have an oxide dry basis content of from 0 to 30% by weight in the total furnish.

7. Process according to claim 1, characterized in that in step 1) the pore former is present in the total furnish in an amount of from 0 to 2% by weight.

8. A method according to claim 1, characterized in that in step 3) a pressure spray drying device or a centrifugal spray drying device is used.

9. A method according to claim 1 wherein the microsphere catalyst is prepared to have an abrasion index of less than two.

10. Use of a microsphere catalyst prepared by the process of claim 1 in the conversion of an oxygenate to an olefin.