CN108452840A - A kind of isomerization catalyst and preparation method - Google Patents

Abstract

The present invention relates to a kind of isomerization catalyst and preparation methods, the isomerization catalyst includes mesoporous 5 molecular sieves of Zn ZSM of 30 ~ 85%H types or improved mesoporous 5 molecular sieves of Zn ZSM by weight percentage, 8 ~ 56% aluminium oxide, magnalium hydrotalcite and/or Kaolin binder, preferably 12 ~ 48%；Impregnate 0.2 ~ 14% metal active constituent.The metal active constituent is one or more of Fe, Co, Ni, Mo and W.The activity and selectivity of catalyst is high, and anti-carbon performance is good.

Description

A kind of isomerization catalyst and preparation method thereof

technical field

The invention relates to the field of petroleum processing catalysts, in particular to an isomerization catalyst with mesoporous Zn-ZSM-5 molecular sieve as a carrier and a preparation method.

Background technique

Gasoline is one of the main fuels used in today's car engines and plays an irreplaceable role. However, with the increasing environmental protection efforts, gasoline standards have gradually increased. Reducing the content of sulfur and olefins is the main task of clean gasoline production, and olefins are high-octane components, and the reduction of their content will inevitably lead to the loss of octane number. The octane number of gasoline can be increased by adding ether compounds, but the added ethers will pollute the ground water. Alkylation technology can also increase the octane number of gasoline, but the catalysts used in this technology are mostly strong acids that pollute the environment and corrode equipment. The catalytic reforming process is also limited because most of the catalytic cracking gasoline in my country is used. At this stage, refineries are more inclined to increase the octane number of gasoline through isomerization technology, and the octane number can be greatly increased by isomerizing straight-chain alkanes into branched-chain alkanes. However, most of the catalysts used in isomerization technology are noble metal catalysts, which are costly and require multi-step pretreatment of raw materials. Therefore, the development of low-cost and high-stability isomerization catalysts is one of the most effective means to improve gasoline quality.

Most hydrocarbon isomerization technologies use dual-functional catalysts containing solid acidic supports and noble metals, that is, solid acidic support materials provide isomerization functions, and metal active components provide dehydrogenation-hydrogenation functions. The metal active site dehydrogenates hydrocarbons to generate carbocations to form an intermediate active transition state, and then undergoes skeletal isomerization on the acid center to generate branched olefin isomerization products, and finally hydrogenates at the metal active site to form branched Paraffins. Due to the existence of side reactions such as hydrocarbon cracking, cyclization and oligomerization in the reaction process, by-products with lower octane numbers are formed, which constitute the main source of octane number loss in the isomerization process. Therefore, the main goal of isomerization technology is to find catalysts with high activity and high selectivity, so as to suppress the occurrence of side reactions.

CN106732752A discloses a kind of preparation method of C5, C6 alkane isomerization catalyst, adopts mordenite and inorganic binder molding, after impregnating with hydrophobic organic amine-alcohol solution, then load platinum, ruthenium, rhodium and palladium etc. VIII Group metals, so that the noble metals can be dispersed on the carrier at the nanometer scale, improve the activity of the catalyst, reduce the load of the noble metals, and save costs.

CN106799257A discloses an alkane isomerization catalyst and a preparation method thereof, which is composed of phosphorus-silicate-aluminum molecular sieve and Group VIII noble metal, and the catalyst exhibits more excellent performance in isomerization reaction.

CN106140189A discloses a preparation method of a light alkane isomerization catalyst and a light alkane isomerization method, through co-precipitation method and hydrothermal treatment method to synthesize solid superacid catalyst, and then load precious metal Pt, used for n-pentane isomerization The catalyst and reaction process have the characteristics of no pollution to the environment, no corrosion of equipment, high activity and selectivity.

CN106635137A discloses a method for isomerizing low-carbon alkanes. The low-carbon alkanes are dehydrated and rectified in sequence, and then contacted with chlorine-containing aluminum oxide to perform hydroisomerization reaction, which can effectively improve the efficiency of the chlorine-containing aluminum oxide catalyst. Isomerization activity, increase product octane number.

Although the above invention improves the activity of the isomerization catalyst, its selectivity has not been significantly improved, and at the same time, it has not fundamentally solved the problem of high cost of noble metals. Therefore the present invention adopts mesoporous Zn-ZSM-5 molecular sieve of low cost, high activity and high selectivity or improved mesoporous Zn-ZSM-5 molecular sieve as acidic carrier, uses Fe, Co, Ni, Mo and W etc. simultaneously Precious metals are used as hydrogenation-dehydrogenation active centers to prepare hydrocarbon isomerization catalysts, which have broad industrial application prospects.

Contents of the invention

In order to solve the above-mentioned problems, the present invention provides a kind of isomerization catalyst and preparation method, catalyst uses mesoporous Zn-ZSM-5 molecular sieve or improved mesoporous Zn-ZSM-5 molecular sieve as carrier, supports Fe, Co, Ni, Mo and W and other active ingredients.

An isomerization catalyst, the isomerization catalyst comprises 30-85% H-type mesoporous Zn-ZSM-5 molecular sieve or improved mesoporous Zn-ZSM-5 molecular sieve, preferably 42-78% by weight percentage %; 8-56% alumina, magnesium-aluminum hydrotalcite and/or binder, preferably 12-48%; impregnating 0.2-14% metal active components, preferably 0.8-8%; said metal active components It is one or more of Fe, Co, Ni, Mo and W, and the loading method is the impregnation method, preferably multiple impregnation methods.

The preparation method of the isomerization catalyst of the present invention is as follows: the mesoporous H-type Zn-ZSM-5 molecular sieve or the improved Zn-ZSM-5 molecular sieve is mixed with alumina, magnesium aluminum hydrotalcite and/or kaolin binder, and then The non-noble metal active component is impregnated and calcined to obtain the isomerization catalyst.

In the H-type mesoporous Zn-ZSM-5 molecular sieve, the mesoporous diameter is concentrated at 4-35nm, and the specific surface area is 350-680m ² /g; the zinc oxide content is 0.2-9.5% of the total weight of the molecular sieve.

The present invention also provides a preparation method of H-type mesoporous Zn-ZSM-5 molecular sieve, comprising the following steps:

(1) At a certain temperature, mix deionized water, aluminum source, zinc source, acid source, templating agent (SDA) and silicon source under stirring conditions to prepare a gel, and adjust the molar ratio of the materials to (0.002-0.06 )Al ₂ O ₃ :(0.04～0.25)Na ₂ O:1SiO ₂ :(10～50)H ₂ O:(0.02～0.25)SDA:(0.001～0.12)ZnO;

(2) After the gel obtained in step (1) is aged, it is transferred to a stainless steel reactor containing a polytetrafluoroethylene liner for sealing and crystallization. After the crystallization is completed, the crystallization product is cooled, filtered to remove the mother liquor, and filtered The cake is washed with deionized water to neutrality, and dried to obtain Zn-ZSM-5 molecular sieve;

(3) The Zn-ZSM-5 molecular sieve obtained in the step (2) is subjected to a series of treatments such as exchange, filtration, drying, and roasting to obtain an H-type Zn-ZSM-5 molecular sieve.

The present invention further improves the mesoporous Zn-ZSM-5 molecular sieve. After obtaining the H-type Zn-ZSM-5 molecular sieve, the surface of the H-type Zn-ZSM-5 molecular sieve is modified by impregnating zinc-containing compounds on the surface of the H-type Zn-ZSM-5 molecular sieve, so that the surface of the molecular sieve The zinc content is higher than the zinc content inside the molecular sieve, and equal-volume impregnation is preferred to obtain an improved H-type Zn-ZSM-5 molecular sieve modified with Zn, that is, an improved Zn-ZSM-5 molecular sieve. Wherein, the zinc-containing compound is one or more of zinc nitrate, zinc acetate, zinc chloride, and zinc sulfate, preferably zinc acetate.

The improved mesoporous Zn-ZSM-5 molecular sieve of the present invention has a mesoporous pore diameter concentrated at 4-35nm and a specific surface area of ^350-680m2 /g; the content of zinc oxide is 0.2-9.5% of the total weight of the molecular sieve, and the zinc oxide on the surface of the molecular sieve is The content is higher than the zinc content inside the molecular sieve, preferably 0.2 to 2 times higher. The silicon source described in step (1) is one or more in water glass, silica sol, orthosilicate, solid silica gel; Described aluminum source is sodium metaaluminate, aluminum isopropoxide, aluminum sulfate One or more of them; the zinc source is one or more of zinc nitrate, zinc acetate, zinc chloride, and zinc sulfate.

The silicon source described in step (1) can also be one or both of diatomite and opal, and the aluminum source can also be one or more of kaolin, retort clay, perlite, and montmorillonite , the zinc source can also be one or both of smithsonite and zincite.

The SDA described in step (1) is one or more of trimethylamine (TMA), methylethylamine, pyrrole, morphine, and can also be commonly used tetrapropyl ammonium hydroxide (TPAOH), tetrapropyl bromide One or more of ammonium (TPABr), 1,6-hexanediamine, n-butylamine, and hexanediol, preferably one or more of trimethylamine (TMA), methylethylamine, pyrrole, and morphine.

The acid source described in step (1) is a mixture of one or more of sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, acetic acid, preferably one or more of sulfuric acid, hydrochloric acid and nitric acid, and the concentration of the acid solution is 0.1 ~8mol/L.

The aging temperature in step (2) is 30-85°C, preferably 40-80°C; the aging time is 1-24h, preferably 2-16h.

The crystallization temperature described in step (2) is 120-210°C, preferably 130-185°C; the temperature is programmed in 1-5 stages, preferably 1-3 stages; it is best to carry out segmented non-isothermal heating, non-isothermal segmentation For heating treatment, the heating rate is first fast and then slow. Before 100°C, the temperature is raised at a heating rate of 6-8°C/min. 20-30°C is a heating section, and the treatment time in the temperature section is 0.5-5 hours; between 100-200°C The temperature is raised at a heating rate of 3-5°C/min, 10-20°C is a heating section, and the treatment time of the temperature section is 0.5-8 hours. The present invention adopts non-isothermal step-by-step heating treatment, which is beneficial to the nucleation rate and growth rate control of the Zn-ZSM-5 molecular sieve crystallization process, can control the size and quantity of mesopores, and can further improve the activity of the catalyst and the selectivity of the target product . The crystallization time is 10-96h, preferably 24-72h.

The roasting temperature described in step (3) is 420-780°C, preferably 450-650°C; the roasting time is 1-8h; the exchange reagent is one of hydrochloric acid, nitric acid, sulfuric acid, ammonium chloride or ammonium nitrate;

The surface modification of the molecular sieve described in step (3) adopts equal volume impregnation of zinc-containing compounds, wherein the mass fraction of ZnO is 0.5-15%, preferably 0.5-10%.

The isomerization catalyst of the present invention is used in the hydroisomerization reaction of n-octane, under the conditions of 180-450°C, 0.5-4.2MPa, WHSV=0.8-8h ^-1 and hydrogen-to-oil volume ratio of 80-450, The conversion rate of n-octane is higher than 88%, and the selectivity of iso-octane is as high as 85.06% at 200°C.

Compared with the prior art, the present invention has the following advantages:

1. The isomerization catalyst prepared by the present invention adopts mesoporous Zn-ZSM-5 molecular sieve or improved mesoporous Zn-ZSM-5 molecular sieve, and non-noble metal is used as hydrogenation-dehydrogenation metal active center component, greatly improving It slows down the poisoning of the metal active center of the catalyst caused by heteroelements such as S contained in the raw material, improves the stability of the catalyst, prolongs the life of the catalyst, and simultaneously improves the activity and selectivity of the catalyst.

2, the present invention synthesizes the Zn-ZSM-5 molecular sieve that skeleton contains Zn by one-step method, and synthetic method is simple, because Zn enters molecular sieve framework and causes crystal structure to change, produces mesopore, has improved the dispersibility of Zn simultaneously, and this will make The diffusion resistance of reactants is reduced, the anti-carbon deposition performance is improved, and the carbon deposition rate is low.

3. The zinc content on the surface of the Zn-ZSM-5 molecular sieve of the present invention is higher than that inside the molecular sieve. The interaction between the Zn atoms on the surface and the Al hydroxyl group leads to the weakening of the strong acid strength to medium strong acid, which reduces the acid strength of the molecular sieve and reduces the hydrocarbons from the root. Side reactions such as cracking occur, which improves the selectivity of isomeric hydrocarbons.

Description of drawings

Fig. 1 is an X-ray diffraction (XRD) spectrum of the Zn-ZSM-5 molecular sieve prepared in Example 1 of the present invention.

Fig. 2 is the _N2 adsorption-desorption isotherm of the Zn-ZSM-5 molecular sieve prepared in Example 1 of the present invention.

Fig. 3 is a pore size distribution diagram of the Zn-ZSM-5 molecular sieve prepared in Example 1 of the present invention.

Fig. 4 is the NH ₃ temperature programmed desorption (NH ₃ -TPD) spectra of Zn-ZSM-5 molecular sieve (synthetic sample) and commercial ZSM-5 molecular sieve (commercial sample) prepared in Example 1 of the present invention.

Detailed ways

The implementation process and beneficial effects of the present invention are described in detail below through specific examples, which are intended to help better understand the essence and characteristics of the present invention, and are not intended to limit the scope of implementation of this case. The commercial sample used in the examples is a ZSM-5 molecular sieve with a SiO ₂ /Al ₂ O ₃ molar ratio of 40.

In order to reflect the isomerization ability of the catalyst to n-octane, the following evaluation indexes are defined: the conversion rate X of n-octane and the selectivity S of isooctane are calculated by formulas (1) and (2).

In the formula:

[A] _{The raw material} is the proportion of n-octane peak area in the raw material, %;

[A] _{The product} is the proportion of n-octane peak area in the product, %;

[B] _{The product} is the proportion of the sum of all isooctane peak areas in the product, %.

Example 1

The present embodiment provides a kind of Ni-Mo/Zn-ZSM-5 catalyst, and its preparation method comprises the following steps:

1. Preparation of mesoporous Zn-ZSM-5 molecular sieve

(1) Weigh 0.44g NaAlO ₂ and 2.14g Zn(NO ₃ ) ₂ ·6H ₂ O and dissolve in 49.55g deionized water, then add 2.00g sulfuric acid (3mol/L) dropwise, stir for 5min and then add 0.93g TMA, After stirring for 1 h, add 14.20 g of water glass (containing 27.6 wt % of SiO ₂ , 7.1 wt % of Na ₂ O and 65.3 wt % of H ₂ O), and mix and stir for 2 h at room temperature. The molar composition of the mixture is 0.003 Al ₂ O ₃ :0.25Na ₂ O:1SiO ₂ :50H ₂ O:0.24SDA:0.11ZnO.

(2) Heat the mixture obtained in step (1) to 75°C for aging for 6 hours, then pour the solution into a stainless steel crystallization kettle lined with polytetrafluoroethylene, raise the temperature to 130°C for crystallization for 12 hours, and then raise the temperature to 180 ℃ static crystallization 24h. After the crystallization is completed, cool and filter to remove the mother liquor, wash until neutral, and dry at 120°C to obtain the crystallized product Zn-ZSM-5 molecular sieve.

(3) Add the Zn-ZSM-5 molecular sieve into the ammonium chloride solution with a concentration of 1mol/L according to the solid-to-liquid ratio of 1:10, mix and stir at 60°C for 4 hours, filter with suction, dry, and re- Exchange once, put it into a muffle furnace and roast at a high temperature of 550° C. for 6 hours to obtain an H-type Zn-ZSM-5 molecular sieve. The XRD spectrum (Fig. 1) can prove that the synthesized sample is a high-purity Zn-ZSM-5 molecular sieve; The _N2 adsorption-desorption isotherm (Fig. 2) and the pore size distribution diagram (Fig. 3) prove that the synthesized Zn-ZSM-5 molecular sieve has a mesoporous structure with double hysteresis ring distribution, and the mesopore diameter is concentrated at 5-30nm. The NH ₃ -TPD spectrum (Figure ⁴ ) proves that the strong acid desorption temperature of the synthesized Zn-ZSM-5 molecular sieve is 350 ° C, while the strong acid desorption temperature of the commercial sample is 480 ° C, indicating that the synthesized Zn -ZSM-5 molecular sieve has significantly lower acid strength, the total acid content is 20% lower than that of commercial ZSM-5 molecular sieve, and the prepared catalyst has strong anti-coking ability. Then impregnate ZnO with a mass fraction of 5%.

2. Preparation of Ni-Mo/Zn-ZSM-5 catalyst

Mix 30g of the above-mentioned Zn-ZSM-5 molecular sieve with 15g of alumina and 20g of deionized water evenly, then extrude, dry at 120°C for 4h, and roast at 550°C for 5h to obtain a molecular sieve carrier, and then use multiple The impregnation method impregnated 5.0wt% NiO and 5.0wt% MoO ₃ to prepare a Ni-Mo/Zn-ZSM-5 catalyst.

Example 2

This example provides a Co-Mo/Zn-ZSM-5 catalyst, the preparation steps are the same as in Example 1, only some parameters are adjusted, as follows:

(1) Using solid silica gel as the silicon source, aluminum sulfate as the aluminum source, zinc nitrate as the zinc source, hydrochloric acid (2mol/L) as the acid source, and a mixture of pyrrole and morpholine (molar ratio 1:1) as SDA, adjust the feeding The molar ratio of the molecular sieve synthesis system is 0.02Al ₂ O ₃ :0.06Na ₂ O:1SiO ₂ :15H ₂ O:0.03SDA:0.002ZnO.

(2) Aging conditions: 50°C, 8h; crystallization conditions: crystallization at 120°C for 12h, crystallization at 150°C for 24h, crystallization at 170°C for 24h.

(3) The solution used for the exchange is 0.5 mol/L hydrochloric acid solution, the calcination temperature is 450°C, the calcination time is 8h, and the mass fraction of impregnated zinc oxide is 12wt%.

(4) The binder is kaolin, and the active metal loading is 2wt% CoO and 6wt% MoO ₃ .

Example 3

This example provides a Ni-Mo/Zn-ZSM-5 catalyst, the preparation steps are the same as in Example 1, only some parameters are adjusted, as follows:

(1) With solid silica gel as the silicon source, aluminum sulfate as the aluminum source, zinc chloride as the zinc source, acetic acid (6mol/L) as the acid source, and methylethylamine as SDA, the molar ratio of the molecular sieve synthesis system is adjusted to _0.04Al2O3 : _0.15Na2O : _1SiO2 : _30H2O :0.15SDA _: 0.06ZnO.

(2) Aging conditions: 40°C, 12h; crystallization conditions: heat up in different stages, first at a heating rate of 7°C/min, 20°C is a heating section, and the processing time of the temperature section is 0.5 hours; 100 After ℃, the temperature is raised at a heating rate of 4°C/min, 10°C is a heating section, and the treatment time of the temperature section is 0.5 hours; the nucleation rate and growth rate of the crystallization process of Zn-ZSM-5 molecular sieve are treated by non-isothermal stage heating Controllable, the size and number of mesopores can be controlled (the distribution of mesopores is more uniform, mainly concentrated at 6-12nm, and the number of mesopores increases by 25%), which in turn can improve the activity of the catalyst and the selectivity of the target product.

(3) The solution used for the exchange is 0.5 mol/L sulfuric acid solution, the calcination temperature is 520°C, the calcination time is 4h, and the mass fraction of impregnated zinc oxide is 6wt%.

(4) The binder is magnesium aluminum hydrotalcite, and the active metal loading is 5wt% NiO and 3wt% MoO ₃ .

Example 4

A Ni-Mo/Zn-ZSM-5 catalyst provided in this example, the preparation steps are the same as in Example 1, only some parameters are adjusted, as follows:

(1) With solid silica gel as the silicon source, aluminum sulfate as the aluminum source, zinc chloride as the zinc source, sulfuric acid (5mol/L) as the acid source, and morpholine as SDA, the molar ratio of the molecular sieve synthesis system is adjusted to _0.05Al2O3 : _0.12Na2O : _{1SiO2 : 20H2O} :0.05SDA:0.01ZnO.

(2) Aging condition: 60°C, 10h; crystallization condition: heat up in different stages, first at a heating rate of 8°C/min, 20°C is a heating section, and the treatment time of the temperature section is 0.5 hours; 100 The heating rate is 3°C/min after 10°C, 10°C is a heating section, and the treatment time of the temperature section is 0.5 hours; the nucleation rate and growth rate of the crystallization process of Zn-ZSM-5 molecular sieve can be controlled by non-isothermal stage heating. Control, can control the size and number of mesopores (the distribution of mesopores is more uniform, mainly concentrated in 10-20nm, and the number of mesopores increases by 32%), which in turn can improve the activity of the catalyst and the selectivity of the target product.

(3) The solution used for the exchange is 0.5 mol/L ammonium nitrate solution, the calcination temperature is 580° C., and the calcination time is 2 hours.

(4) The active metal loading is 5wt% NiO and 3wt% MoO ₃ .

Example 5

This example provides a Ni-Mo/Zn-ZSM-5 catalyst, the preparation steps are the same as in Example 3, only some parameters are adjusted, as follows:

(1) Use the activated opal as the silicon source, the activated rectorite as the aluminum source, the activated smithsonite as the zinc source, the acetic acid (6mol/L) as the acid source, and the methylethylamine as the SDA to adjust the feeding amount The molar ratio of the molecular sieve synthesis system is 0.015Al ₂ O ₃ :0.20Na ₂ O:1SiO ₂ :40H ₂ O:0.09SDA:0.04ZnO. Among them, the activation of opal is to roast opal at 600 ° C for 4 hours, and the activation of rectorite is to mix rectorite minerals and NaOH according to the mass ratio of 1:1.5, add a small amount of water to extrude, and dry at 160 ° C. The activation of zinc ore is to roast smithsonite at 800°C for 4 hours.

Example 6

This embodiment provides a Ni-Mo/Zn-ZSM-5 catalyst, the preparation steps are the same as in Example 1, only the preparation of the catalyst in step 2 is adjusted, as follows:

(1) 28g of the above-mentioned Zn-ZSM-5 molecular sieves were mixed evenly with 13g of alumina and 16g of deionized water, then extruded, dried at 120°C for 4h, and roasted at 600°C for 5h to obtain a molecular sieve carrier, and then Ni-Mo/Zn-ZSM-5 catalyst was prepared by impregnating 7.0wt% NiO and 4.5wt% MoO ₃ by multiple impregnation method.

Example 7

In this embodiment, the catalyst is used for fixed bed reaction test activity, comprising the following steps:

The 5g catalyst prepared in the above-mentioned Example 1 was packed in the reaction tube on the micro-fixed-bed reactor device, and the temperature began to rise at room temperature, and the heating rate was 2°C/min. After keeping at 320°C for 2 hours, the vulcanization is completed, and the temperature is naturally lowered to 200°C for 2 hours, and the reaction product is collected for analysis. During the whole process, the feed rate of n-octane was maintained at 10 g/h, the system pressure was 2.0 MPa, and the volume ratio of hydrogen to oil was 300. The results of the catalytic reactions are shown in Table 1.

Example 8

In this example, the catalyst was used to test the activity of the fixed-bed reaction. The steps were the same as in Example 7, except that the parameters were different: the catalyst was the catalyst obtained in Example 2, and the reaction temperature was 250°C.

Example 9

In this example, the catalyst was used to test the activity of the fixed bed reaction, and the steps were the same as in Example 7, except that the parameters were different: the catalyst was the catalyst obtained in Example 3, and the reaction temperature was 300°C.

Example 10

In this example, the catalyst was used to test the activity of the fixed bed reaction. The steps were the same as in Example 7, but the parameters were different in that: the catalyst was the catalyst obtained in Example 4, and the reaction temperature was 280°C.

Example 11

In this example, the catalyst was used to test the activity of the fixed bed reaction, and the steps were the same as in Example 7, except that the parameters were different: the catalyst was the catalyst obtained in Example 5, and the reaction temperature was 260°C.

Example 12

In this example, the catalyst was used to test the activity of the fixed bed reaction, and the steps were the same as in Example 7, except that the parameters were different: the catalyst was the catalyst obtained in Example 6, and the reaction temperature was 250°C.

Comparative example 1

In order to prove the technical effect of the technical solution of the present invention, the present invention also provides a comparative example. The molecular sieve used in this comparative example is a commercial microporous ZSM-5 molecular sieve, and the steps of molding and impregnation are the same as in Example 1.

Comparative example 2

In this example, the catalyst was used to test the activity of the fixed bed reaction, and the steps were the same as in Example 7, except that the parameters were different: the catalyst was the catalyst obtained in Comparative Example 1, and the reaction temperature was 280°C.

Comparative example 3

The preparation of the carrier of this comparative example is the same as in Example 4, except that the crystallization process is a stepwise isothermal heating, 140° C. for 12 hours, and 170° C. for 24 hours. The preparation and composition of the catalyst are the same as in Example 4, and the evaluation conditions are the same as in Example 8.

The assay result of the isomerization product of each embodiment of table 1 and comparative example

Conversion rate(%) Isomer selectivity (%) Cracking rate (%) Coke rate (%) Example 7 88.60 85.06 14.36 0.18 Example 8 91.03 86.19 13.20 0.20 Example 9 95.68 88.69 11.01 0.24 Example 10 92.55 87.31 12.33 0.15 Example 11 90.94 89.52 10.12 0.25 Example 12 88.54 83.79 15.53 0.42 Comparative example 2 99.18 3.56 95.27 1.12 Comparative example 3 96.67 70.28 28.31 0.95

As can be seen from Table 1, the catalyst provided by the invention has excellent isomerization reactivity, has higher isoparaffin selectivity and lower cracking rate (i.e. high liquid yield) and comparative example Coke rate. Under the conditions described in Example 9, a stability test was carried out on the catalyst. The results showed that after 1000 hours of reaction, the conversion rate and isomer selectivity of the catalyst remained above 90.0 and 88.5%, respectively, and the cracking rate and coke formation rate Respectively lower than 10.5,0.28%. Therefore, the catalyst provided by the invention has more excellent isomerization ability, and has good economic benefits and industrial application prospects.

Claims (10)

1. An isomerization catalyst, characterized in that: in weight percent, comprising 30~85% H type mesoporous Zn-ZSM-5 molecular sieve or improved mesoporous Zn-ZSM-5 molecular sieve, 8~56% oxidation Aluminum, magnesium aluminum hydrotalcite and/or kaolin binder, impregnated with 0.2-14% metal active components, the metal active components are one or more of Fe, Co, Ni, Mo, W. 2. The isomerization catalyst according to claim 1, characterized in that: the H-type mesoporous Zn-ZSM-5 molecular sieve has a mesoporous diameter concentrated at 4-35 nm and a specific surface area of 350-680 m ² /g, the zinc oxide content is 0.2~9.5% of the total weight of the molecular sieve. 3. The isomerization catalyst according to claim 1, characterized in that: the improved mesoporous Zn-ZSM-5 molecular sieve has a mesoporous pore diameter concentrated at 4-35 nm and a specific surface area of 350-680 m ² / g, the zinc oxide content is 0.2-9.5% of the total weight of the molecular sieve, and the zinc content on the surface of the molecular sieve is higher than that inside the molecular sieve. 4. The isomerization catalyst according to claim 3, characterized in that: the surface zinc content of the improved mesoporous Zn-ZSM-5 molecular sieve is 0.2-2 times higher than the internal zinc content of the molecular sieve. 5. a kind of preparation method of isomerization catalyst as claimed in claim 1 is characterized in that: it comprises the steps: with H type mesoporous Zn-ZSM-5 molecular sieve or improved Zn-ZSM-5 molecular sieve and oxidation Aluminum, magnesium-aluminum hydrotalcite and/or kaolin binder are mixed and molded, then non-precious metal active components are impregnated and calcined to obtain the isomerization catalyst. 6. the preparation method of isomerization catalyst according to claim 5, is characterized in that: the preparation method of described H type mesoporous Zn-ZSM-5 molecular sieve, comprises the steps: (1) At a certain temperature, mix deionized water, aluminum source, zinc source, acid source, templating agent SDA and silicon source under stirring conditions to prepare a gel, and adjust the molar ratio of the materials to (0.002~0.06)Al ₂ O ₃ : (0.04~0.25)Na ₂ O: 1SiO ₂ : (10~50)H ₂ O: (0.02~0.25)SDA: (0.001~0.12)ZnO; (2) After the gel obtained in step (1) is aged, it is transferred to a stainless steel reactor containing a polytetrafluoroethylene liner for sealing and crystallization. After the crystallization is completed, the crystallization product is cooled, filtered to remove the mother liquor, and filtered The cake is washed with deionized water to neutrality, and dried to obtain Zn-ZSM-5 molecular sieve; (3) Exchanging, filtering, drying and roasting the Zn-ZSM-5 molecular sieve obtained in step (2) to obtain H-type mesoporous Zn-ZSM-5 molecular sieve. 7. the preparation method of isomerization catalyst according to claim 6, is characterized in that: the preparation method of described improved Zn-ZSM-5 molecular sieve is as follows: will obtain H type mesoporous Zn-ZSM-5 molecular sieve impregnation again The zinc-containing compound is modified so that the zinc content on the surface of the molecular sieve is higher than that inside the molecular sieve. 8. the preparation method of isomerization catalyst according to claim 6 is characterized in that: the aluminum source described in step (1) is one or more in sodium metaaluminate, aluminum isopropoxide, aluminum sulfate; The silicon source is one or more of water glass, silica sol, tetraethyl orthosilicate, and solid silica gel; the zinc source is one or more of zinc nitrate, zinc acetate, zinc chloride, and zinc sulfate. Several kinds. 9. the preparation method of isomerization catalyst according to claim 6 is characterized in that: the silicon source described in step (1) is one or both in diatomite, opal, and aluminum source is kaolin, rector One or more of soil, perlite, and montmorillonite, and the zinc source is one or two of smithsonite and zincite. 10. according to the preparation method of the described isomerization catalyst of claim 6, it is characterized in that, the crystallization temperature described in step (2) is 120 ~ 210 ℃, divides 1 ~ 5 sections and carries out subsection non-isothermal heating treatment, The heating rate is first fast and then slow. Before 100 ℃, the heating rate is 6~8 ℃/min, and 20~30 ℃ is a heating section, and the treatment time of the temperature section is 0.5~5 hours; between 100~200 ℃, the temperature is 3 The temperature is raised at a heating rate of ~5 ℃/min, 10-20 ℃ is a heating section, and the treatment time of the temperature section is 0.5-8 hours.