CN110064418B

CN110064418B - Oxidation state reforming catalyst and preparation method thereof

Info

Publication number: CN110064418B
Application number: CN201810063594.9A
Authority: CN
Inventors: 潘晖华; 韩晓琳; 胡长禄
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2018-01-23
Filing date: 2018-01-23
Publication date: 2021-11-02
Anticipated expiration: 2038-01-23
Also published as: CN110064418A

Abstract

The invention discloses an oxidation state reforming catalyst and a preparation method thereof, wherein the preparation method comprises the following steps: step 1, preparing a tin-containing alumina carrier; step 2, dipping the carrier in the step 1 at the dipping temperature of 10-50 ℃, wherein the dipping liquid comprises a platinum-containing compound, a rare earth compound, a competitive adsorbent and a nitrogen-containing compound; and step 3, drying and activating the impregnated carrier in the step 2 to obtain a reforming catalyst; wherein the reforming catalyst comprises 0.1-0.4 mass% of platinum, 0.1-0.6 mass% of tin, 0.05-1 mass% of rare earth and 0.3-3.0 mass% of chlorine based on the total mass of the dry-based alumina carrier. The catalyst is used for catalytic reforming reaction of hydrocarbons, can reduce the generation of coke and improve the selectivity of aromatic hydrocarbon products.

Description

Oxidation state reforming catalyst and preparation method thereof

Technical Field

The invention relates to a reforming catalyst and a preparation method thereof, in particular to an oxidation state reforming catalyst containing light rare earth and a preparation method thereof.

Background

Catalytic reforming is one of the important production processes for petroleum processing, with the main objective of producing high octane gasoline, BTX aromatics, and inexpensive hydrogen. With the upgrading of gasoline and diesel oil quality and the rapid development of hydrogenation technology, the catalytic reforming is more and more important in the oil refining chemical industry. Currently, the most commonly used reforming catalyst in the industry is Pt-Re/A1 for semi-regenerative reforming processes₂O₃Catalyst and Pt-Sn/A1 for continuous regenerative reforming process₂O₃。

Typical metrics for catalyst performance include activity, selectivity, and stability. For reforming catalysts, the activity is inThe aromatic hydrocarbon content or octane value of the product obtained under the given raw material and reaction condition, or the reaction temperature under the given octane value; selectivity refers to the yield of aromatics or C at a given activity level₅ ⁺Yield of gasoline product; stability refers to the change in catalyst activity or selectivity per unit time or unit throughput. High performance reforming catalysts should have high activity and selectivity, as well as high stability.

USP3915845 discloses a hydrocarbon conversion multi-metal catalytic component, which comprises 0.01-2.0 wt% of Pt group metal, 0.01-5.0 wt% of germanium, 0.1-3.5 wt% of halogen and lanthanide compounds. The lanthanide in the catalyst is lanthanum, cerium and neodymium.

USP4039477 discloses a hydrotreating catalyst modified with a lanthanide metal and its use. The catalyst comprises a refractory metal oxide, a Pt group metal, Sn and at least one metal selected from Y, Th, U, Pr, Ce, La, Nd, Sm, Dy and Gd. According to the method, lanthanide metal is added into the catalyst, so that the activity stability of the catalyst is improved, and the existence of tin can reduce the cracking activity of the catalyst containing lanthanide metal, thereby being beneficial to improving the selectivity.

USP6059960 discloses a rare earth-containing Pt-Sn multi-metal reforming catalyst incorporating lanthanide elements of Eu, Yb, Sm or a mixture of Eu and Yb, and more than 50% of the lanthanide metal in the catalyst is present as EuO. When the catalysts are all Pt-Sn-Eu components, the relative activity and selectivity are good only when the Eu/Pt atomic ratio is 1.3-2.0, when the ratio is less than 1.3, the selectivity of the catalyst is reduced, and when the ratio is more than 2.0, the catalytic activity is obviously reduced.

USP6007700 discloses a reforming catalyst characterized by: the carrier is made of eta-Al₂O₃And gamma-Al₂O₃The composition comprises at least one doping metal selected from Ti, Zr, Hf, Co, Ni, Zn and lanthanide metals, at least one halogen element, at least one Pt group element and one auxiliary metal selected from Sn, Ge, In, Ga, Tl, Sb, Pb, Re, Mn, Cr, Mo and W. The catalyst is in a strip shape because the carrier of the catalyst is extruded and formed.

CN 02809057 discloses a multi-metal reforming catalyst containing platinum and tin, and preparation and application thereof, wherein lanthanide elements introduced by the catalyst are Eu and Ce. The catalyst has high activity and selectivity when used for reforming naphtha, low carbon deposition rate and long service life.

CN 201310178694 discloses a multi-metal reforming catalyst, which contains 0.3 mass% of Pt, 0.3 mass% of Sn, 0.1-0.5 mass% of Y, 0.5-1.0 mass% of Sm and 1.1-1.3 mass% of Cl.

CN 201410532295 discloses a preparation method of a multi-metal reforming catalyst, which comprises the steps of enabling catalyst pellets uniformly loaded with platinum, tin and rare earth metal to be in solid-phase contact with powder of rare earth metal salt, then roasting in air or water-containing air, wherein the average content of the rare earth metal in an outer shell area of the obtained reforming catalyst is 2-5 times of the average content of the rare earth metal in a central area, the outer shell area of the catalyst is an area with the thickness of 150 mu m towards the central direction of the outer edge of the catalyst pellet, and the rare earth metal in the catalyst is preferably europium or samarium.

CN1715370A discloses a preparation method of a Pt-Sn-rare earth reforming catalyst, which is characterized in that a proper amount of organic amine is added into an impregnation liquid to adjust the pH value of the impregnation liquid, prevent rare earth metals from losing in the impregnation process and simultaneously ensure that VIII group metals have enough loading capacity and are uniformly distributed in a carrier.

CN 201280029171 discloses a catalyst for catalytic reforming of naphtha. The catalyst may have a noble metal comprising one or more of platinum, palladium, rhodium, ruthenium, osmium, and iridium, a lanthanide metal comprising one or more elements of atomic numbers 57-71 of the periodic table, and a support. The lanthanide to noble metal atomic ratio is less than 1.3: 1. The lanthanide metal can be distributed in a 100 μm surface layer of the catalyst with a lanthanide metal concentration that is less than 2 times the concentration of the lanthanide metal at the central core of the catalyst.

For a reforming catalyst having excellent performance, in addition to the requirement for uniform distribution of the Pt component on the support, it is also required that the Pt component have a small particle size so that hydrogenolysis and carbon formation reactions can be suppressed. The Pt particle size analysis method comprises the methods of chemical adsorption, electron microscopy, infrared and the like. This is achieved byIn addition, a rapid and simple method H₂TPR method, which can not obtain a quantitative value of Pt particle size, but can qualitatively judge the Pt particle size by reducing peak temperature by fixing TPR analysis conditions, and a higher reducing peak temperature corresponds to a smaller Pt particle size.

The existing reforming catalyst products have an oxidation state and also a reduction state. For the oxidation state catalyst, the catalyst production plant does not need to add a hydrogen reduction unit, and the catalyst is reduced on a refinery device. For the reduction catalyst, the catalyst is reduced in a production plant, the catalyst can be directly started when being loaded into a refinery device, but the storage process of the reduction catalyst needs nitrogen protection, the catalyst loading process cannot avoid contacting air, and if the storage time of the catalyst is long, the device needs to be supplemented for reduction.

Disclosure of Invention

The invention mainly aims to provide an oxidation state reforming catalyst and a preparation method thereof, which are used for solving the problems that the catalyst platinum cluster has larger particle size and coke and carbon are easy to generate caused by side reaction in the catalytic reforming process in the prior art.

In order to achieve the above object, the present invention provides a method for preparing an oxidation state reforming catalyst, comprising the steps of:

step 1, preparing a tin-containing alumina carrier;

step 2, dipping the carrier in the step 1 at the dipping temperature of 10-50 ℃, wherein the dipping liquid comprises a platinum-containing compound, a rare earth compound, a competitive adsorbent and a nitrogen-containing compound; and

step 3, drying and activating the impregnated carrier in the step 2 to obtain a reforming catalyst;

wherein the reforming catalyst comprises 0.1-0.4 mass% of platinum, 0.1-0.6 mass% of tin, 0.05-1.0 mass% of rare earth and 0.3-3.0 mass% of chlorine based on the total mass of the dry-based alumina carrier.

In the preparation method of the oxidation state reforming catalyst, part or all of chlorine in the reforming catalyst comes from competitive adsorbents, and the competitive adsorbents preferably comprise one or more of hydrochloric acid, dichloroacetic acid and trichloroacetic acid.

In the method for preparing an oxidation state reforming catalyst, the shape of the alumina carrier is preferably spherical.

In the preparation method of the oxidation state reforming catalyst, the platinum-containing compound is preferably one or more of the group consisting of chloroplatinic acid, potassium chloroplatinate, ammonium chloroplatinate, platinum tetrachloride, platinum nitrate, tetraammineplatinum chloride and tetraammineplatinum hydroxide.

The method for preparing an oxidation state reforming catalyst according to the present invention is characterized in that the rare earth compound is preferably one or more selected from the group consisting of a lanthanum compound, a cerium compound, a praseodymium compound, a neodymium compound, a promethium compound, a samarium compound, and an europium compound.

The preparation method of the oxidation state reforming catalyst provided by the invention is characterized in that the rare earth compound is preferably one or more of the group consisting of lanthanum nitrate, lanthanum chloride, cerous nitrate, cerium nitrate, praseodymium chloride, neodymium acetate, samarium chloride and europium nitrate.

In the preparation method of the oxidation state reforming catalyst, the nitrogen-containing compound is preferably urea, and the amount of the urea in the impregnation liquid is preferably 0.01-5.0 mass% of the total mass of the dry-based alumina carrier.

In the step 2, the liquid-solid volume ratio of the impregnation liquid to the carrier is preferably 0.5-3: 1, and the impregnation time is preferably 0.1-4 hours.

In the preparation method of the oxidation state reforming catalyst, in the step 3, the activating atmosphere is preferably air, the activating temperature is preferably 200-650 ℃, and the activating time is preferably 0.5-10 hours.

In order to achieve the above object, the present invention also provides a catalyst prepared by the above method for preparing an oxidation state reforming catalyst.

The invention has the beneficial effects that:

according to the invention, the nitrogen-containing compound, preferably urea, is added into the impregnation liquid, so that the interaction between the metal components and the carrier is enhanced, the metal components are not easy to aggregate, and the particle size of the platinum cluster of the catalyst is smaller;

the particle size of the platinum cluster is reduced, so that the occurrence of hydrogenolysis side reaction in the reforming reaction process can be reduced, the hydrogenolysis byproduct methane is reduced, and the selectivity of the product aromatic hydrocarbon is improved.

Detailed Description

The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.

The invention provides a preparation method of an oxidation state reforming catalyst, which comprises the following steps:

step 1, preparing a tin-containing alumina carrier;

wherein the reforming catalyst comprises 0.1-0.4 mass% of platinum, 0.1-0.6 mass% of tin, 0.05-1 mass% of rare earth and 0.3-3.0 mass% of chlorine based on the total mass of the dry-based alumina carrier.

The step of preparing the tin-containing alumina support of the present invention is not particularly limited as long as the requirements of the present invention are satisfied. The shape of the alumina carrier can be strip shape, cloverleaf shape or spherical shape, and the spherical alumina carrier is preferred. The spherical alumina carrier can be prepared by a rolling ball or dropping ball method, the spherical alumina carrier can be prepared firstly, and then Sn element is introduced by an immersion method, or Sn element is introduced in the preparation process of the spherical alumina carrier, such as rolling ball or during the preparation of dropping ball colloid, preferably Sn element is introduced during dropping ball colloid, and the content of Sn added is 0.1-0.6 mass percent based on the total mass of the dry-based alumina carrier.

Then, the prepared tin-containing alumina carrier is impregnated with active components at the impregnation temperature of 10-50 ℃. The impregnation liquid includes a platinum-containing compound, a rare earth compound, a competitive adsorbent, and a nitrogen-containing compound. The platinum-containing compound is one or more selected from the group consisting of chloroplatinic acid, potassium chloroplatinate, ammonium chloroplatinate, platinum tetrachloride, platinum nitrate, tetraammineplatinum chloride and tetraammineplatinum hydroxide, preferably chloroplatinic acid. The content of platinum in the platinum-containing compound in the impregnation liquid is 0.1 to 0.4 mass% based on the total mass of the dry-based alumina carrier. The rare earth compound is preferably one or more selected from the group consisting of lanthanum compound, cerium compound, praseodymium compound, neodymium compound, promethium compound, samarium compound and europium compound; further preferably one or more of the group consisting of lanthanum nitrate, lanthanum chloride, cerous nitrate, cerium nitrate, praseodymium chloride, neodymium acetate, samarium chloride and europium nitrate. The content of rare earth in the impregnation liquid is 0.05-1% by mass based on the total mass of the dry-based alumina carrier. The competitive adsorbent comprises one or more of hydrochloric acid, dichloroacetic acid and trichloroacetic acid, preferably trichloroacetic acid, hydrochloric acid or a combination of hydrochloric acid and trichloroacetic acid, and the content of chlorine in the competitive adsorbent in the impregnation liquid is 0.3-3.0 mass% based on the total mass of the dry-based alumina carrier. The nitrogen-containing compound is preferably urea, and the amount of urea in the impregnation liquid is preferably 0.01 to 5.0 mass% of the total mass of the dry-based alumina carrier.

The urea can enhance the interaction between the metal components and the carrier, so that the metal components are not easy to aggregate, and further the particle size of the platinum cluster of the catalyst is smaller. However, if the impregnation temperature is too high (for example, the impregnation temperature exceeds 75 ℃), urea in the impregnation solution is hydrolyzed, so that the pH value is increased, Pt is aggregated, and Pt grains are enlarged.

The impregnation method of the present invention is not particularly limited as long as the amount of the active metal supported on the alumina carrier satisfies the requirements of the present invention. The impregnation method can be a saturated impregnation method or a supersaturated impregnation method, and the liquid-solid volume ratio of the impregnation liquid to the carrier is preferably 0.5-3: 1. The impregnation process can be static impregnation or dynamic impregnation, wherein the dynamic impregnation refers to the rotation of an impregnation container in the impregnation process, and dynamic impregnation is preferred. The dipping temperature is 10-50 ℃, and the dipping time is 0.1-4 hours.

The impregnated mixture is directly dried, activated and reduced without being filtered to obtain the reforming catalyst. The drying may be ordinary drying or vacuum drying, and preferably vacuum drying. The vacuum drying pressure is 0.001-0.08 MPa, and the vacuum drying temperature is 50-60 ℃. The vacuum drying temperature needs to be strictly controlled, and the vacuum drying temperature is over 75 ℃, which can cause urea in the impregnation liquid to be hydrolyzed, so that the pH value is increased, Pt is aggregated, and Pt grains are enlarged.

The activation refers to roasting the dried catalyst in an activation atmosphere, wherein the activation atmosphere is air, the activation temperature is 200-650 ℃, preferably 450-550 ℃, and the activation time is 0.5-10 hours, preferably 1-4 hours.

The oxidation state reforming catalyst obtained by the invention takes the total mass of a dry-based alumina carrier as a reference, and comprises 0.1-0.4 mass% of platinum, 0.1-0.6 mass% of tin, 0.05-1 mass% of rare earth and 0.3-3.0 mass% of chlorine. The catalyst contains 5% of H₂The TPR (temperature programmed reduction) test was carried out at a temperature increase rate of 5 ℃/min in a flowing Ar atmosphere, and the peak temperature of the first reduction peak of Pt was more than 260 ℃.

The chlorine in the oxidation state reforming catalyst of the present invention is derived in part or in whole from the competing sorbent.

The catalyst is suitable for the naphtha reforming process to produce high-octane gasoline blending components or aromatic hydrocarbons. The naphtha is preferably an oil rich in naphthenes and paraffins and may be straight run gasoline, hydrocracked heavy naphtha, thermally or catalytically cracked gasoline fractions, and Fischer-Tropsch gasoline. Measured according to the method of ASTM D-86, for example, full boiling range gasoline with an initial boiling point of 40-80 ℃ and an end boiling point of 160-220 ℃, light naphtha with a boiling range of 60-150 ℃ or heavy naphtha with a boiling range of 100-200 ℃.

When the catalyst of the invention is used in a catalytic reforming reaction process, the catalytic reforming reaction conditions are as follows: absolute pressure of 100kPa7MPa, preferably 0.35 to 2.5 MPa; the reaction temperature is 315-600 ℃, preferably 425-565 ℃; the hydrogen/hydrocarbon molar ratio is 1-20, preferably 2-10; the Liquid Hourly Space Velocity (LHSV) is 0.1-10 h^-1Preferably 1 to 5 hours^-1。

The catalytic reforming process is carried out under substantially anhydrous conditions. The water content of the raw oil entering the catalytic reforming conversion region should be less than 50ppm, preferably less than 20 ppm. The water in the reformed feedstock may be dried by a conventional adsorbent such as molecular sieve, or may be adjusted by appropriate stripping operation in a fractionation unit, or may be removed by a combination of adsorption drying and stripping drying.

The contents of Pt, Sn and rare earth in the catalyst are measured by an X-ray fluorescence method, and the content of chlorine is measured by an electrode method.

The technical solution of the present invention is further illustrated by the following specific examples.

Example 1

100 g of pseudo-boehmite (manufactured by Sasol company) and a proper amount of deionized water are taken, the liquid/solid mass ratio is 2, and the mixture is stirred and pulped for 0.5 hour at room temperature. Then, 3 ml of nitric acid and a hydrochloric acid solution of stannous chloride in a predetermined amount were added to make the Sn content in the solution 0.30 mass% with respect to the dry alumina, and the solution was acidified for 2 hours. Then dropping balls in an oil ammonia column for forming, solidifying the wet balls in ammonia water for 1 hour, then filtering, washing with deionized water for three times, drying at 60 ℃ for 6 hours, drying at 120 ℃ for 2 hours, and roasting at 650 ℃ for 4 hours in a flowing air atmosphere to obtain the Sn-containing alumina pellet carrier.

Preparing impregnation liquid containing chloroplatinic acid, cerous nitrate, hydrochloric acid and urea according to a predetermined amount, wherein the content of platinum, the content of cerium, the content of HCl and the content of urea in the impregnation liquid are respectively 0.29 percent, 0.23 percent, 1.8 percent and 3.2 percent relative to the content of dry-based alumina. And (3) dipping the carrier prepared in the previous step by the dipping solution, wherein the liquid/solid volume ratio of the dipping solution to the carrier is 1.8, the dipping temperature is 15 ℃, and the dipping time is 1 hour. Then, the excess of the maceration extract was evaporated to dryness at 60 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to give catalyst A, the composition of which is shown in Table 1.

Example 2

Catalyst B was prepared as in example 1, except that the rare earth compound in the impregnation solution was europium nitrate, and the specific steps were as follows:

Preparing impregnation liquid containing chloroplatinic acid, europium nitrate, hydrochloric acid and urea according to a predetermined amount, wherein the content of platinum, the content of europium, the content of HCl and the content of urea in the impregnation liquid are respectively 0.29 percent, 0.23 percent, 1.8 percent and 3.2 percent relative to the content of dry-based alumina. And (3) dipping the carrier prepared in the previous step by the dipping solution, wherein the liquid/solid volume ratio of the dipping solution to the carrier is 1.8, the dipping temperature is 15 ℃, and the dipping time is 1 hour. Then, the excess of the maceration extract was evaporated to dryness at 60 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to obtain catalyst B, the composition of which is shown in Table 1.

Example 3

An alumina pellet carrier in which the Sn content was 0.40 mass% relative to the dry alumina was prepared by the method of example 1.

Catalyst C was prepared as in example 1, except that the rare earth compound in the impregnation solution was cerous chloride, and the platinum content, cerium content, HCl content and urea content in the impregnation solution were 0.36%, 0.89%, 2.7% and 4.8% respectively, based on the amount of dry alumina. The carrier prepared in the previous step is soaked by the soaking liquid, the liquid/solid volume ratio of the soaking liquid to the carrier is 1.3, the soaking temperature is 30 ℃, the soaking time is 3 hours, and the method comprises the following specific steps:

100 g of pseudo-boehmite (manufactured by Sasol company) and a proper amount of deionized water are taken, the liquid/solid mass ratio is 2, and the mixture is stirred and pulped for 0.5 hour at room temperature. Then, 3 ml of nitric acid and a hydrochloric acid solution of stannous chloride in a predetermined amount were added to make the Sn content in the solution 0.40 mass% with respect to the dry alumina, and the mixture was acidified for 2 hours. Then dropping balls in an oil ammonia column for forming, solidifying the wet balls in ammonia water for 1 hour, then filtering, washing with deionized water for three times, drying at 60 ℃ for 6 hours, drying at 120 ℃ for 2 hours, and roasting at 650 ℃ for 4 hours in a flowing air atmosphere to obtain the Sn-containing alumina pellet carrier.

Preparing impregnation liquid containing chloroplatinic acid, cerous chloride, hydrochloric acid and urea according to a predetermined amount, wherein the content of platinum, the content of cerium, the content of HCl and the content of urea in the impregnation liquid are respectively 0.36 percent, 0.89 percent, 2.7 percent and 4.8 percent relative to the content of dry-based alumina. The carrier prepared in the previous step is soaked by the soaking liquid, the liquid/solid volume ratio of the soaking liquid to the carrier is 1.3, the soaking temperature is 30 ℃, and the soaking time is 3 hours. Then, the excess of the maceration extract was evaporated to dryness at 60 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to obtain catalyst C, the composition of which is shown in Table 1.

Example 4

An alumina pellet carrier in which the Sn content was 0.24 mass% relative to the dry alumina was prepared by the method of example 1.

Catalyst D was prepared as in example 1, except that the rare earth compound in the impregnation solution was lanthanum nitrate and the platinum content, lanthanum content, HCl content and urea content in the impregnation solution were 0.23%, 0.31%, 3.0% and 0.01% respectively, relative to the amount of dry alumina. The liquid/solid volume ratio of the impregnation liquid to the carrier was 1.8, the impregnation temperature was 40 ℃ and the impregnation time was 0.1 hour. The excess of the maceration extract was evaporated to dryness under vacuum at 50 ℃. The method comprises the following specific steps:

100 g of pseudo-boehmite (manufactured by Sasol company) and a proper amount of deionized water are taken, the liquid/solid mass ratio is 2, and the mixture is stirred and pulped for 0.5 hour at room temperature. Then, 3 ml of nitric acid and a hydrochloric acid solution of stannous chloride in a predetermined amount were added to make the Sn content in the solution 0.24 mass% with respect to the dry alumina, and the solution was acidified for 2 hours. Then dropping balls in an oil ammonia column for forming, solidifying the wet balls in ammonia water for 1 hour, then filtering, washing with deionized water for three times, drying at 60 ℃ for 6 hours, drying at 120 ℃ for 2 hours, and roasting at 650 ℃ for 4 hours in a flowing air atmosphere to obtain the Sn-containing alumina pellet carrier.

Preparing impregnation liquid containing chloroplatinic acid, lanthanum nitrate, hydrochloric acid and urea according to a predetermined amount, wherein the content of platinum, the content of lanthanum, the content of HCl and the content of urea in the impregnation liquid are respectively 0.23 percent, 0.31 percent, 3.0 percent and 0.01 percent relative to the content of dry-based alumina. The carrier prepared in the previous step is soaked by the soaking liquid, the liquid/solid volume ratio of the soaking liquid to the carrier is 1.8, the soaking temperature is 40 ℃, and the soaking time is 0.1 hour. Then, the excess of the maceration extract was evaporated to dryness at 50 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to obtain catalyst D, the composition of which is shown in Table 1.

Example 5

Catalyst E was prepared as in example 4 except that the rare earth compound in the impregnation solution was praseodymium chloride and the praseodymium content and urea content in the impregnation solution were 0.46% and 2.6% respectively relative to the dry alumina content. The liquid/solid volume ratio of impregnating solution to carrier was 1.4. The method comprises the following specific steps:

Preparing impregnation liquid containing chloroplatinic acid, praseodymium chloride, hydrochloric acid and urea according to a predetermined amount, wherein the content of platinum, the content of praseodymium, the content of HCl and the content of urea in the impregnation liquid are respectively 0.23 percent, 0.46 percent, 3.0 percent and 2.6 percent relative to the content of dry-based alumina. And (3) dipping the carrier prepared in the previous step by the dipping solution, wherein the liquid/solid volume ratio of the dipping solution to the carrier is 1.4, the dipping temperature is 40 ℃, and the dipping time is 0.1 hour. Then, the excess of the maceration extract was evaporated to dryness at 50 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to give catalyst E, the composition of which is shown in Table 1.

Example 6

Catalyst F was prepared as in example 5 except that the rare earth compound in the impregnation solution was samarium chloride and the samarium and urea contents in the impregnation solution were 0.12% and 1.5% relative to the dry alumina mass. The method comprises the following specific steps:

Preparing impregnation liquid containing chloroplatinic acid, samarium chloride, hydrochloric acid and urea according to a predetermined amount, wherein the content of platinum, the content of samarium, the content of HCl and the content of urea in the impregnation liquid are respectively 0.23 percent, 0.12 percent, 3.0 percent and 1.5 percent relative to the content of dry-based alumina. And (3) dipping the carrier prepared in the previous step by the dipping solution, wherein the liquid/solid volume ratio of the dipping solution to the carrier is 1.4, the dipping temperature is 40 ℃, and the dipping time is 0.1 hour. Then, the excess of the maceration extract was evaporated to dryness at 50 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to obtain catalyst F, the composition of which is shown in Table 1.

Example 7

Catalyst G was prepared as in example 5, except that the rare earth compound in the impregnating solution was neodymium acetate and the neodymium content and urea content in the impregnating solution were 0.18% and 1.9% relative to the dry alumina mass. The method comprises the following specific steps:

Preparing impregnation liquid containing chloroplatinic acid, neodymium acetate, hydrochloric acid and urea according to a predetermined amount, wherein the content of platinum, the content of neodymium, the content of HCl and the content of urea in the impregnation liquid are respectively 0.23 percent, 0.18 percent, 3.0 percent and 1.9 percent relative to the content of dry-based alumina. And (3) dipping the carrier prepared in the previous step by the dipping solution, wherein the liquid/solid volume ratio of the dipping solution to the carrier is 1.4, the dipping temperature is 40 ℃, and the dipping time is 0.1 hour. Then, the excess of the maceration extract was evaporated to dryness at 50 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to obtain catalyst G, the composition of which is shown in Table 1.

Example 8

An alumina pellet carrier in which the Sn content was 0.12 mass% relative to the dry alumina was prepared by the method of example 1.

Catalyst H was prepared as in example 1 except that the rare earth compounds in the impregnation solution were lanthanum chloride and cerous chloride and the lanthanum content, cerium content and urea content in the impregnation solution were 0.07%, 0.07% and 0.8%, respectively, relative to the amount of dry alumina. The method comprises the following specific steps:

100 g of pseudo-boehmite (manufactured by Sasol company) and a proper amount of deionized water are taken, the liquid/solid mass ratio is 2, and the mixture is stirred and pulped for 0.5 hour at room temperature. Then, 3 ml of nitric acid and a hydrochloric acid solution of stannous chloride in a predetermined amount were added to make the Sn content in the solution 0.12 mass% with respect to the dry alumina, and the solution was acidified for 2 hours. Then dropping balls in an oil ammonia column for forming, solidifying the wet balls in ammonia water for 1 hour, then filtering, washing with deionized water for three times, drying at 60 ℃ for 6 hours, drying at 120 ℃ for 2 hours, and roasting at 650 ℃ for 4 hours in a flowing air atmosphere to obtain the Sn-containing alumina pellet carrier.

Preparing impregnation liquid containing chloroplatinic acid, lanthanum chloride, cerous chloride, hydrochloric acid and urea according to a predetermined amount, wherein the platinum content, the lanthanum content, the cerium content, the HCl content and the urea content in the impregnation liquid are respectively 0.17 percent, 0.07 percent, 1.6 percent and 0.8 percent relative to the dry-based alumina content. And (3) dipping the carrier prepared in the previous step by the dipping solution, wherein the liquid/solid volume ratio of the dipping solution to the carrier is 1.8, the dipping temperature is 15 ℃, and the dipping time is 1 hour. Then, the excess of the maceration extract was evaporated to dryness at 60 ℃ under vacuum, and dried at 120 ℃ for 2 hours. The dried catalyst precursor was activated in air at 500 ℃ for 4 hours to give catalyst H, the composition of which is given in Table 1.

Comparative examples 1 to 3

Catalysts were prepared as in examples 1, 3, 6 except that the impregnation solution did not contain urea. The composition of the resulting catalyst P, Q, R is shown in Table 1.

Comparative example 4

The catalyst was prepared as in example 2 except that the excess impregnation was evaporated to dryness at 85 ℃ under vacuum. The composition of the catalyst S obtained is shown in Table 1.

Comparative example 5

A catalyst S was prepared by following the procedure of example 5 in patent CN 02809057, taking 100 g of the Sn-containing carrier obtained in the above example 1, and impregnating the carrier with 180 ml of an impregnation solution containing cerium nitrate and europium nitrate in predetermined amounts, wherein the cerium content and the europium content in the impregnation solution were 0.49% and 0.16% respectively relative to the dry alumina content. The dipping temperature is 25 ℃, the dipping time is 24 hours, the solid obtained by filtering is dried for 6 hours at 60 ℃, and after being dried for 10 hours at 120 ℃, the solid is roasted for 4 hours at 600 ℃ in air containing 2-3% of water vapor.

Impregnating the carrier prepared in the previous step with a mixed solution of chloroplatinic acid, hydrochloric acid and trichloroacetic acid prepared according to a preset amount, wherein the content of platinum, the content of HCl and the content of trichloroacetic acid in the mixed solution are 0.31 percent, 1.2 percent and 5.0 percent relative to the content of dry-based alumina, the liquid/solid volume ratio of the impregnated mixed solution to the carrier is 1.8, and the impregnation time is 24 hours. The solid after the impregnation filtration was activated in air at 510 ℃ in a molar ratio of water to HC1 of 60:1 for 6 hours to give catalyst T, the composition of which is given in Table 1.

Comparative example 6

An alumina-containing support was prepared by following the procedure of example 1 except that tin chloride and europium chloride were used in place of tin chloride, and the content of tin in the support was 0.30 mass% and the content of europium was 0.20 mass% based on the total mass of the dry-based alumina support.

Catalyst U was prepared according to the method of patent CN1715370A, 100 g of the above carrier was taken and impregnated with 180 ml of a solution containing ethanolamine, hydrochloric acid and chloroplatinic acid, the platinum content and HCl content in the impregnation solution were 0.29% and 2.5%, respectively, with respect to the dry alumina content, and the ratio of the amounts of ethanolamine and HCl substances was 0.39. Soaking for 24 hr, separating the mother liquor from the solid with an acid-resistant filter funnel, drying the solid at 120 deg.C for 5 hr, and drying at 510 deg.C under H₂The catalyst U was obtained by activation treatment with water and chlorine in air at an O/HCl molecular ratio of 40:1 for 3 hours, the composition of U being shown in Table 1.

The urea content in the impregnation liquid mentioned in each example and comparative example refers to the percentage of the urea content in the impregnation liquid to the total mass of the dry-based alumina carrier.

TABLE 1 composition of the catalyst

Example 9

In this example, TPR analysis of the catalyst was conducted.

The catalyst TPR analysis was carried out using an apparatus of Micromeritics AutoChem 2920. Pretreatment conditions of the sample: 0.5 g of catalyst is loaded into a U-shaped quartz tube, and the temperature is raised to 400 ℃ at the speed of 10 ℃/min in He gas flow at the flow rate of 50mL/min, and the pretreatment is carried out for 2 h. Cooling to room temperature, then adding 5% H at a flow rate of 30mL/min₂The temperature in-Ar gas flow is raised to 650 ℃, and the temperature raising rate is 5 ℃/min. The peak temperature of the first reduction peak of catalyst Pt was recorded and the results are shown in table 2.

TABLE 2 Peak temperature of first reduction Peak of catalyst Pt

The results in Table 2 show that the catalyst prepared by the invention has relatively small particle size of the metal component, relatively strong interaction between the metal component and the carrier, and relatively high initial reduction temperature of the corresponding metal component.

Example 10

This example evaluates the performance of the catalysts of the examples of the invention and the comparative examples.

In a micro-reactor, 2 g of catalyst was charged, and the catalyst pretreatment conditions were: dry air is introduced, and the volume space velocity is 700h^-1Keeping the temperature of 250 ℃ and 480 ℃ for 1h respectively, introducing hydrogen and reducing at 480 ℃ for 2h with the volume space velocity of 500h, wherein the nitrogen is qualified by replacement^-1. The catalyst evaluation conditions were: takes n-heptane as raw material, the reaction temperature is 470 ℃, the reaction pressure is 0.80MPa, and the mass space velocity is 2h^-1The hydrogen/hydrocarbon molar ratio was 3, the reaction time was 22 hours, the reaction product was subjected to on-line chromatographic analysis, the chromatogram was an agilent 6890 gas chromatogram equipped with an FID detector and a capillary column, and the evaluation results are shown in table 3.

Conversion X ═ C₇ ^I-C₇ ^o)/C₇ ^I，

C₇ ^IIs the n-heptane concentration at the inlet of the reactor,

C₇ ^ois the reactor outlet n-heptane concentration.

Selectivity is

Y_iIn order to obtain the yield of the i component,

x is the n-heptane conversion.

TABLE 3 evaluation results of catalysts

As can be seen from Table 3, compared with the catalyst prepared by the comparative example, the catalyst prepared by the embodiment of the invention has high activity, the selectivity of the aromatic hydrocarbon of the product obtained by catalysis is high, and the selectivity of the isomerized product is high; compared with the catalyst prepared by the comparative example, the catalyst prepared by the invention reduces the occurrence of hydrogenolysis side reaction and reduces the product methane of hydrogenolysis reaction; compared with the catalyst prepared by the comparative example, the catalyst prepared by the invention reduces cracking reaction, and the cracked products C3-C4 are reduced.

The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method of preparing an oxidation state reforming catalyst, the method comprising the steps of:

step 1, preparing a tin-containing alumina carrier;

wherein the reforming catalyst comprises 0.1-0.4 mass% of platinum, 0.1-0.6 mass% of tin, 0.05-1.0 mass% of rare earth and 0.3-3.0 mass% of chlorine based on the total mass of the dry-based alumina carrier;

wherein the nitrogen-containing compound is urea, the drying is vacuum drying, and the vacuum drying temperature is 50-60 ℃.

2. A method of preparing an oxidation state reforming catalyst according to claim 1, wherein part or all of the chlorine in the reforming catalyst is from a competing adsorbent comprising one or more of hydrochloric acid, dichloroacetic acid and trichloroacetic acid.

3. The method of preparing an oxidation state reforming catalyst according to claim 1, wherein the alumina support is spherical in shape.

4. The method of claim 1, wherein the platinum-containing compound is one or more of the group consisting of chloroplatinic acid, potassium chloroplatinate, ammonium chloroplatinate, platinum tetrachloride, platinum nitrate, tetraammineplatinum chloride, and tetraammineplatinum hydroxide.

5. A method of preparing an oxidized state reforming catalyst as defined in claim 1, wherein the rare earth compound is one or more of the group consisting of lanthanum compounds, cerium compounds, praseodymium compounds, neodymium compounds, promethium compounds, samarium compounds, and europium compounds.

6. The method of claim 5, wherein the rare earth compound is one or more of the group consisting of lanthanum nitrate, lanthanum chloride, cerous nitrate, cerium nitrate, praseodymium chloride, neodymium acetate, samarium chloride, and europium nitrate.

7. The method according to claim 1, wherein the urea is present in the impregnating solution in an amount of 0.01 to 5.0% by mass based on the total mass of the dry alumina support.

8. The method of claim 1, wherein in step 2, the liquid-solid volume ratio of the impregnating solution to the support is 0.5 to 3:1, and the impregnating time is 0.1 to 4 hours.

9. The method of claim 1, wherein in step 3, the activating atmosphere is air, the activating temperature is 200-650 ℃, and the activating time is 0.5-10 hours.

10. A catalyst prepared by the method of preparing an oxidation state reforming catalyst according to any one of claims 1 to 9.