RU2584951C1 - Method of producing catalyst support for conversion of hydrocarbon raw material based on mesoporous material - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: invention relates to method of producing catalyst carrier for conversion of hydrocarbon raw material based on mesoporous material. Method consists in preparing mesoporous material from zirconium hydroxide by deposition of hydroxy phase from composition consisting of hydrated zirconium oxide, aqueous solution of mineral acid and template, which is tetraalkylammonium bromide or chloride, in which one of alkyls is presented in form of C_nH_2n+1, where n=10-20, while three other alkyls are presented in the form of methyl, ethyl, or butyl. Stabilisation of obtained precipitate by silicon oxide is performed at temperature of 105-120°C and pressure of up to 0.7 MPa for 10-45 hours to produce mesoporous structure, drying with subsequent, if necessary, control of acidity and calcination. Produced mesoporous material is mixed with fine powder of aluminium oxide in ratio of 1:20 to 3:1, resolved produced mix by water with addition of nitric acid, blowing agent and a plasticiser, extruded, sammed in air and drying of extrudates is conducted. Drying mode is stepped temperature increase at 60, 80 and 110 °C with exposure at each temperature step for 2.5-3 hours. Dried extrudates calcined in air flow at temperature of 500-550 °C for 3-4 hours in mode of slow temperature increase to mentioned for 7-8 hours.

EFFECT: this ensures combination of developed specific surface and uniform size of pores, available for hydrocarbon molecules, possibility of additional modification of inner surface of pores by forming specific active centres and sufficient mechanical strength of granules.

2 cl, 3 tbl, 12 ex

Description

The invention relates to catalytic chemistry, in particular to the preparation of supports for catalysts for the conversion of hydrocarbons based on mesoporous material, and can be used in the refining industry.

The main component of the hydrocarbon feed conversion catalyst carrier is a mesoporous material, which is a mesoporous zirconium oxide, providing a combination of high activity and selectivity of the catalysts. Therefore, it is possible to influence the properties of the resulting active phase of the catalyst by forming a carrier with the required characteristics. Thus, the activity and selectivity of the catalyst is determined primarily by the chemical and phase composition, the porous structure of the carrier, which largely depend on the method of its preparation.

Currently, it is possible to use pore-forming and pore-regulating materials, as well as materials with a mesoporous structure, as part of the carrier. This allows you to synthesize a fundamentally new media, characterized by a highly developed surface, a large pore volume in combination with high mechanical strength.

Mesoporous graphite-like carbon material, which is a three-dimensional matrix with a pore volume of 0.2 ÷ 1.7 cm ³ / g, formed by tape layers of carbon with a thickness of 100 ÷ 10000 Å and with a radius of curvature of 100 ÷, is known as a catalyst carrier for purification of a hydrogen-containing gas mixture from CO. 10000 Å, having a true density of 1.80 ÷ 2.10 g / cm ³ , an X-ray density of 2.112 ÷ 2.236 g / cm ³ , a porous structure with a pore distribution with a maximum in the range of 200 ÷ 2000 Å, or a biporous structure with a pore distribution with additional maximum in range zone of 40-200 Å and a specific surface of 50-500 m ² / g. RU 2336947 C1, 10.27.2008.

, где Э = элемент III или IV группы Периодической таблицы Д.И. Менделеева, x=1,5 или 2, содержание $$S{O}_4^{2-}$$

составляет 0,1-10 масс. %, мольное соотношение ZrO₂:ЭO_x=1:(0,4÷1,0), и имеющий удельную поверхность 300-800 м²/г с суммарным объемом пор 0,3-0,8 см³/г. Known mesoporous material based on zirconium oxide, having the composition $$S{O}_{\mathrm{four}}^{2-}/Zr{O}_2-E{O}_x$$

where E = element of group III or IV of the Periodic table D.I. Mendeleev, x = 1.5 or 2, content $$S{O}_{\mathrm{four}}^{2-}$$

is 0.1-10 mass. %, molar ratio ZrO ₂ : EO _x = 1: (0.4 ÷ 1.0), and having a specific surface area of 300-800 m ² / g with a total pore volume of 0.3-0.8 cm ³ / g.

To obtain the mesoporous material, a composition is prepared consisting of hydrated zirconium oxide, anion sulfate and water, by precipitation of the hydrated oxide phase from soluble zirconium or zirconyl salts and subsequent hydrothermal reprecipitation in the presence of cationic surfactants with the formation of a mesoporous structure. Stabilization of the obtained mesoporous structure is carried out by treatment with silicon oxide or alumina taken in predetermined ratios to the mesoporous crystalline phase to obtain the mesoporous structure, and calcining. RU 2280504 C1, 07.07.2006.

The main drawback of most known zirconium-based mesoporous materials is their insufficient thermal stability: when calcined in air at temperatures of 450-500 ° C, a significant destruction of the mesoporous structure formed during synthesis is observed, which is accompanied by a decrease in the specific surface.

A known method of preparing a catalyst carrier for the implementation of the hydrogenation of arenes described in RU 2309796 C1, 10.11.2007. The method consists in mixing moistened powders of aluminum hydroxide and crystalline mesoporous aluminosilicate with a Si / Al molar ratio of 10-60, the mixture is moistened, gelled with a 1.5-5.0% nitric acid solution with continuous stirring at a temperature of 5 -10 ° C to obtain a homogeneous mass and carry out the molding of granules by extrusion, drying and calcination.

The disadvantages include insufficiently high mechanical strength for carriers used in the processing of high molecular weight raw materials at pressures exceeding 7.0 MPa.

A known method of preparing a catalyst carrier for the process of hydrofining oil fractions, according to which active aluminum hydroxide with a moisture content of 78% is mixed with zirconium nitric acid to obtain a homogeneous mass, molded by extrusion, the extrudates are dried at a temperature of 120 ° C, calcined at a temperature of 550- 600 ° C, receive a carrier with a coefficient of cracking strength of 1.9 kg / mm diameter. RU 2216404 C1, 11.20.2003.

The disadvantage of this invention can be attributed to the fact that the method of preparation of the carrier does not provide sufficient strength of the carrier and hydrodesulfurization activity of the catalyst prepared on its basis.

An object of the present invention is to develop a method for producing a catalyst carrier for transformations of a hydrocarbon feedstock based on a mesoporous material, which is a mesoporous zirconium oxide, with desired properties. The carrier obtained by the claimed method has a specific surface area of more than 200 m ² / g, a pore volume of at least 0.40 cm ³ / g and a granule strength of at least 3.5 kg / granule.

The technical result from the implementation of the invention is the provision of a combination of the developed specific surface area and pore sizes uniformized for hydrocarbon molecules, the possibility of additional modification of the inner surface of the pores due to the formation of specific active centers and sufficient mechanical strength of the granules.

The technical result is achieved by preparing a mesoporous material from zirconium hydroxide by precipitation of the hydroxide phase from a composition consisting of hydrated zirconium oxide, an aqueous solution of mineral acid and a template, using tetraalkylammonium bromide or chloride, in which one of the alkyls is represented as C _n H _{2n + 1} where n = 10-20, and the other three alkyl presented as methyl, ethyl, propyl or butyl, stabilization is carried out resulting precipitate silica at a temperature of 105-120 ° C and PRESSURE and up to 0.7 MPa for 10-45 hours to obtain a mesoporous structure, drying followed by, if necessary, adjusting the acidity and calcining, after which the obtained mesoporous material based on zirconium hydroxide is mixed with finely divided alumina powder in a ratio of 1:20 up to 3: 1, the resulting mixture is peptized with water with the addition of nitric acid, a pore-forming agent and a plasticizer, extruded, dried in air and the extrudates are dried with a stepwise increase in temperature at 60, 80 and 110 ° C with exposure to and each temperature stage for 2.5-3 hours and calcination of the dried extrudates in a stream of air at a temperature of 500-550 ° C for 3-4 hours in a mode of slow temperature increase to the specified 7-8 hours

The preparation of the catalyst carrier by the method proposed in this invention is carried out as follows.

до полного растворения осадка. К полученному раствору добавляют водный раствор катионного сурфактанта галогенида алкилтриметиламмония (C_nH_2n+1(C_mH_2m+1)₃NX, где n=10-20, m=1-4, X=Cl, Br) в мольном соотношении 1,0 Zr:(0,2-0,5)C_nH_2n+1(C_mH_2m+1)₃NX:(400-600)Н₂О и выдерживают в автоклаве при температуре 105-145°C и давлении до 0,7 МПа в течение 15-45 ч. По окончании кристаллизации полученный мезопористый кристаллический материал на основе оксида циркония, содержащий органическую матрицу, фильтруют, промывают и сушат на воздухе.In the first stage, a solution of a zirconium or zirconyl salt (ZrOCl ₂ , ZrO (NO ₃ ) ₂ , ZrCl ₄ , Zr (So ₄ ) ₂ ) is treated with an aqueous ammonia solution in a molar ratio of 1.0Zr: (3.5-4.5) NH ₃ . The precipitate obtained is separated, washed with water, and then treated with sulfuric acid in a molar ratio $$\mathrm{1,0}Zr:(\mathrm{1,5}-\mathrm{2,5})S{O}_{\mathrm{four}}^{2-}$$

until the precipitate is completely dissolved. An aqueous solution of a cationic surfactant of alkyltrimethylammonium halide (C _n H _{2n + 1} (C _m H _{2m + 1} ) ₃ NX, where n = 10-20, m = 1-4, X = Cl, Br) in molar ratio is added to the resulting solution 1.0 Zr: (0.2-0.5) C _n H _{2n + 1} (C _m H _{2m + 1} ) ₃ NX: (400-600) H ₂ O and kept in an autoclave at a temperature of 105-145 ° C and pressure up to 0.7 MPa for 15-45 hours. Upon completion of crystallization, the obtained mesoporous crystalline material based on zirconium oxide containing an organic matrix is filtered, washed and dried in air.

In the second stage, the mesoporous crystalline phase of zirconium oxide is stabilized. For this, a mixture containing the initial form of the mesoporous crystalline phase, the composition R ₄ NOH-SiO ₂ (where R = Me, Et) and water in a molar ratio of 1.0 ZrO ₂ : (0.4-1.0) SiO ₂ :( 0.1-1.0) R ₄ NOH: (100-300) H ₂ O, maintained at a temperature of 40-100 ° C for 4-60 hours. After crystallization, the stabilized form of the mesoporous crystalline phase of zirconium oxide is filtered, washed and are dried.

In the third stage, the resulting material is treated with an aqueous solution of acids H _n A (sulfuric, tungsten phosphoric, etc.) or their ammonium salts in a molar ratio of 1.0 Zr: (0.01-0.1) A ^n- , where n = 1- four. The material is dried and calcined in air at a temperature of 500-800 ° C for 4-8 hours.

, при этом содержание стабилизатора в мезопористом материале не превышает мольного соотношения 1,0 ZrO₂:0,6 ЭО_х, где x=1,5 или 2.In a preferred embodiment, the molar ratio of the chemical composition is $$\mathrm{1,0}Zr{O}_2:(0.4-\mathrm{1,0})Si{O}_2:(0.01-0.1)S{O}_{\mathrm{four}}^{2-}$$

while the stabilizer content in the mesoporous material does not exceed a molar ratio of 1.0 ZrO ₂ : 0.6 EO _x , where x = 1.5 or 2.

In a fourth step, a predetermined amount of the obtained mesoporous zirconium oxide is mixed with the calculated amount of Pural or Disperal alumina powder (Sasol) until homogeneous. The calculated amount of water and nitric acid used as a peptizing agent and triethylene glycol as a pore-forming agent and plasticizer are added. The resulting mass is triturated and stirred with heating until a homogeneous state is achieved. The mass is extruded using an extruder with a die diameter of 1.5-2.0 mm. The resulting extrudates are dried in air for 24 hours and dried with a stepwise increase in temperature at 60, 80, and 110 ° C with holding at each temperature step for 2.5-3 hours. The dried granules are calcined in a stream of air in the mode of slowly raising the temperature to 500-550 ° C for 7 hours and at a temperature of 500-550 ° C for 3 hours

The result is a zirconium aluminum oxide carrier having a specific surface area of 200-350 m ² / g, a pore volume of 0.40-0.49 cm ³ / g and a mechanical strength coefficient of 3.5-3.9 kg / granule.

A specific implementation of the method is disclosed in the following examples. Obtaining a mesoporous material based on zirconium oxide is illustrated by Examples 1-10. The conditions for preparing the material are summarized in Table 1.

Physico-chemical characteristics of materials based on zirconium oxide obtained after calcination in air at 550 ° C, prepared in accordance with the proposed method, are summarized in Table 2.

The characteristics of the catalyst carriers obtained by the method corresponding to the invention are presented in Table 3.

Example 1

The synthesis of mesoporous material is carried out in two stages.

In the first step, 10.12 g (0.03 mol) of zirconyl chloride (ZrOCl ₂ · 8H ₂ O) is dissolved in 60 g of water. The resulting solution is treated with 4.4 ml of a 25% aqueous NH ₄ OH solution until the hydrated oxide phase is completely precipitated. The precipitate was filtered off, washed on the filter with water and then treated with 6.16 g (0.06 mol) of concentrated sulfuric acid until the hydrated oxide phase was completely dissolved. To the resulting mixture was added 37.1 g of water. The resulting solution was added dropwise with vigorous stirring for 30 minutes to a solution of a surfactant containing 7.86 g (0.016 mol) of cetyltributylammonium bromide in 175 g of water. The mixture was placed in an autoclave and kept at a temperature of 100 ° C for 45 hours. The product was cooled to room temperature, separated by filtration, washed on a filter with water and dried at room temperature for 48 hours.

In the second stage, the mesoporous phase is stabilized, 10 g of the dry product obtained in the first stage is suspended in 50 g of water. To the resulting suspension, with stirring, add a solution containing 2.93 g (0.045 mol) of silicon oxide, 32.96 ml of a 20% solution (0.045 mol) of tetraethylammonium hydroxide in water and 15 g of water. The mixture was placed in an autoclave and kept at a temperature of 120 ° C for 30 hours. The product was cooled to room temperature, separated by filtration, washed on a filter with water and dried at room temperature for 48 hours. The product was calcined in a muffle furnace in an air stream at a temperature of 550 ° C for 6 hours

Example 2

The synthesis is carried out according to Example 1, the synthesis temperature is 120 ° C, and the synthesis time is 20 hours

Example 3

The synthesis is carried out according to Example 1. Instead of cetyltributylammonium bromide, 6.95 g (0.016 mol) of octadecyltriethylammonium bromide are taken. The synthesis temperature is 110 ° C, and the synthesis time is 30 hours

Example 4

The synthesis is carried out according to Example 1. Instead of cetyltributylammonium bromide, 6.13 g (0.016 mol) of cetyltrimethylammonium bromide are taken. The synthesis temperature is 100 ° C and the synthesis time is 45 hours. The stabilization time is 6 hours.

Example 5

The synthesis is carried out according to Example 4. The stabilization time is 20 hours

Example 6

The synthesis is carried out according to Example 4. The synthesis temperature is 140 ° C, and the synthesis time is 15 hours. The stabilization time is 30 hours.

Example 7

The synthesis of mesoporous material is carried out in three stages. The first and second stages are carried out according to Example 4. The stabilization time is 35 hours

At the third stage, acid properties are regulated. 10 g of the dry product obtained in the second stage is treated with a solution of 0.5 g (0.005 mol) of sulfuric acid in 50 g of water. The mixture was kept at room temperature for 1 h, and then evaporated and dried at 100 ° C for 2 h. The product was calcined in a muffle furnace in a stream of air at 550 ° C for 6 h.

Example 8

The synthesis is carried out according to Example 7. The acidity is regulated by a solution of 0.66 g (0.005 mol) of ammonium sulfate in 50 g of water.

Example 9

At the first stage, zirconium sulfate is taken as the starting compound, 15 g (0.042 mol) of Zr (SO ₄ ) ₂ · 4H ₂ O are dissolved in 50 g of water. The resulting solution was added dropwise with vigorous stirring for 30 minutes to a solution of 21.55 ml of 25% cetyltrimethylammonium chloride in 159 ml of water. The mixture was kept in an autoclave at a temperature of 105 ° C for 45 hours. The product was cooled to room temperature, separated by filtration, washed on the filter with water and dried at room temperature for 48 hours.

Example 10

The synthesis is carried out according to Example 7. In the second stage, the mesoporous phase is stabilized by aluminum compounds. 10 g of the dry product obtained in the first step are suspended in 50 g of water. To the resulting suspension, with stirring, add a solution containing 4.14 g (0.040 mol) of hydrated alumina, 28.9 ml of a 20% solution (0.045 mol) of tetraethylammonium hydroxide in water and 30 g of water. The mixture was placed in an autoclave and kept at 110 ° C for 30 hours. The product was cooled to room temperature, separated by filtration, washed on the filter with water and dried at room temperature for 48 hours.

The specific surface and pore volume were measured on a Mircomertics ASAP 2020 adsorption porosimeter using nitrogen adsorption. The specific surface was calculated according to the BET model (Brunauer-Emmett-Teller) at a relative partial pressure P / P ₀ = 0.2. The total pore volume and pore radius distribution were calculated from the adsorption curve using the BJH (Barrett-Joyner-Halenda) model at a relative partial pressure P / P ₀ = 0.99.

The preparation of the carrier is illustrated but not limited by the examples below.

Example 11

To prepare carrier No. 1, 100 ml of water and a peptizer solution are poured slowly with stirring to 100.0 aluminum hydroxide powder and 31.80 g of mesoporous zirconium oxide obtained in Example 6. As a peptizer, a solution of nitric acid is used, which is prepared by adding 4.25 ml of HNO ₃ (65%) in 40.00 ml of distilled water. To the resulting mass was added 7.10 ml of triethylene glycol as a pore-forming agent and plasticizer, and then stirred. The resulting mass is molded on a screw extruder with a die diameter of 1.5 mm The extrudates are air dried for 24 hours, then placed in a drying oven for a stepwise increase in temperature at 60, 80, and 110 ° C with exposure at each temperature step for 2.5 hours. The dried catalyst carrier is transferred to a muffle furnace for calcination in continuous air supply mode. The rate of temperature rise is 50-70 ° C / h to 500 ° C. Exposure at a temperature of 500 ° C - 5 hours.

Example 12

To prepare carrier No. 2, 10.6 g of mesoporous zirconium oxide obtained in Example 6 are added to 100.0 g of aluminum hydroxide powder, and they are thoroughly mixed. Then slowly add a solution of peptizer with triethylene glycol. As a peptizer, a solution of nitric acid is used, which is prepared by adding 3.23 ml of HNO ₃ (65%) in 25.64 ml of distilled water. To the resulting solution was added 5.37 ml of triethylene glycol as a pore-forming agent and plasticizer, and then stirred. The mass is then molded on a screw extruder with a die diameter of 1.5 mm. The formed granules are dried in air for 24 hours, then placed in a drying oven for a stepwise increase in temperature at 60, 80, and 110 ° C with exposure at each temperature step for 3 hours. The dried catalyst carrier is transferred to a muffle furnace for calcination in continuous air supply. The rate of temperature rise is 50-70 ° C / h to 550 ° C. Exposure at a temperature of 550 ° C - 4 hours.

The resulting carrier, corresponding to the proposed invention, has a broad prospect of application for use in the composition of the catalysts for the conversion of hydrocarbon feedstocks. The prospect is determined by the features of the crystal structure of the proposed carrier, combining a highly developed specific surface, uniform pore sizes available for hydrocarbon molecules, and the possibility of additional modification of the inner surface of the pores due to the formation of specific active centers and sufficient mechanical strength.

Claims (2)

1. A method of producing a catalyst carrier for transforming a hydrocarbon feedstock based on a mesoporous material, comprising preparing a mesoporous material from zirconium hydroxide by precipitating the hydroxide phase from a composition consisting of hydrated zirconium oxide, an aqueous solution of a mineral acid, and a template, using tetraalkylammonium bromide or chloride in which one of the alkyls is represented as C _n H _{2n + 1} , where n = 10-20, and the other three alkyls are presented as methyl, ethyl, propyl or butyl, one hundred bilizing the obtained precipitate with silicon oxide at a temperature of 105-120 ° C and pressure up to 0.7 MPa for 10-45 h to obtain a mesoporous structure, drying followed by, if necessary, adjusting the acidity and calcining, after which the obtained mesoporous oxide-based material zirconium is mixed with a fine powder of alumina in a ratio of from 1:20 to 3: 1, the mixture is peptized with water with the addition of nitric acid, a pore-forming agent and a plasticizer, extruded, dried in air and air dried dates at a stepwise increase in temperature at 60, 80 and 110 ° C with holding at each temperature stage for 2.5-3 hours and calcination of the dried extrudates in an air stream at a temperature of 500-550 ° C for 3-4 hours in slow mode raising the temperature to the indicated in 7-8 hours 2. The method according to p. 1, characterized in that triethylene glycol is used as a pore-forming agent and plasticizer.