RU2055014C1 - Hydrocarbon raw material conversion method and method to produce catalyst for its realization - Google Patents

Abstract

FIELD: chemical industry. SUBSTANCE: method provides for carrying conversion of hydrocarbon raw material with oxidizer (steam, carbon dioxide or their mixture) in presence of catalyst, that has 0.3 - 10.0 mass % of nickel oxide applied on carrier, that has aluminum oxides and/ or zirconium oxides with addition of metal oxides from group of calcium, barium, strontium under mole ratio of aluminum oxides and/or zirconium oxides and additions equal to (1 - 6) : 1 correspondingly. Catalyst preparation process is described. EFFECT: improved technology. 10 cl 2 tbl

Description

 The invention relates to processes for the catalytic conversion of hydrocarbons and can be used in the chemical, petrochemical and gas industries.

 Two main directions of increasing the economic efficiency of units for the production of hydrogen by methane conversion are reducing the oxidizer / carbon ratio and increasing the load. Work in such modes requires the use of catalysts combining high activity and resistance to carbonization. For existing hydrocarbon conversion catalysts, these requirements contradict each other.

 A known catalyst containing 1-40 wt. nickel oxide on a carrier including oxides of magnesium, zirconium and silicon (see USSR author's certificate N 192091, class B 01 J, publ. 1967). As follows from the description, a high carbonization resistance of such a catalyst is achieved by using a low nickel oxide content, and a high activity of a high nickel oxide content. The combination of these two properties is achieved due to the combined loading of the reactor, the frontal layer, operating under conditions of increased threat of carbonization, is loaded with a catalyst with a low nickel oxide content, while the required degree of reforming is achieved by loading the subsequent part of the reactor with a highly active catalyst with a high content of nickel oxide. Thus, this catalyst does not solve the problem of combining high resistance to carburization and activity at the scale of an individual catalyst granule. In addition, the catalyst contains silicon oxide, the presence of which is unacceptable for a number of modern methane steam reforming units operating under a pressure of 2-4 MPa.

Also known is a catalyst with a low nickel content (0.01-0.7 wt.) On a carrier consisting mainly of zirconia (US Patent No. 3476536, 48-214, 1969). However, such a catalyst does not have sufficient activity to be used in modern highly intense hydrogen production units operating at space velocities of 2000-3000 h ^-1 . The maximum volumetric feed rate of the convertible mixture described in the patent is 1000 h ^-1 , which is more than 2 times lower than the required. The insufficient activity of zirconia catalysts is also confirmed by the results of later studies (Jens R. Rostrup-Nielsen. "Steam reforming catalysts", Tecknisk Forlag A / S (Danish tecknical press inc. Copenhagen, 1975, p. 125), in which extremely low specific catalytic activity of nickel on a zirconia support It is obvious that a high resistance to carbonization of such a catalyst was also achieved by reducing its activity.

The closest to the invention is a process for converting a hydrocarbon feedstock comprising contacting feedstock with an oxidant in the presence of nickel-containing catalyst at elevated temperature (700-800 ° ^C). When this is used, the catalyst brand GIAP-18 composition, wt. NiO not less than 11.0 Al ₂ O ₃ not less than 70.0 CaO 6-10 (see Catalysts of the nitrogen industry, Cherkasy, 1989, p. 6 prototype).

 Due to the high content of nickel oxide, the catalyst has high activity, but low resistance to carburization (Table 1). The catalyst is easily carbonized when operating at low oxidizer / feed ratios.

There is also known a method of producing a catalyst for the conversion of hydrocarbon feedstock, comprising preparing a carrier by mixing the starting oxides or compounds (Al ₂ O ₃ and CaO), forming them, hydrothermal treatment, firing and subsequent impregnation of the carrier with a solution containing a nickel compound and heat treatment to obtain a catalyst of the above composition (prototype).

 The aim of the invention is the creation of technologies for the process of catalytic conversion of hydrocarbon feeds that occur efficiently at a low oxidizer / carbon ratio and the preparation of a catalyst with increased resistance to carbonization while maintaining its high activity.

 This is solved by the method of conversion of hydrocarbon feedstock, comprising reacting the feedstock with an oxidizing agent in the presence of a nickel-containing catalyst at an elevated temperature, in which the reaction is carried out in the presence of a catalyst containing 0.3-10.0 wt. nickel oxide deposited on a carrier containing aluminum and / or zirconium oxides with additives of metal oxides from the group of: calcium, barium, strontium with a molar ratio of aluminum and / or zirconium oxides and additive oxides equal to (1-6): 1, respectively.

 Moreover, water vapor, carbon dioxide or mixtures thereof are used as an oxidizing agent.

According to the invention, the reaction is carried out at 450-950 ^C, a pressure of 0.1-4.0 MPa and a space velocity of hydrocarbons 2000-4000 h ^-1.

The problem is also solved by a method of producing a catalyst for the conversion of hydrocarbon raw materials, including the preparation of a carrier by mixing the initial oxides or metal compounds, their molding, hydrothermal treatment, firing, subsequent impregnation of the carrier with a solution containing nickel compounds and heat treatment, in which a mixture of aluminum and / or zirconium oxides or their compounds with additives of oxides from the group: calcium, barium, strontium or a mixture thereof or their compounds is carried out in a molar ratio (1-6): 1, respectively, after which the resulting mixture was molded, calcined at 1350-1500 ^{° C} for 1-8 hours, then subjected to a hydrothermal treatment and the resulting product is calcined at 120-190 ^{° C} and impregnated with a heated solution containing a nickel compound at a concentration of 20-150 g / l in terms of nickel, followed by heat treatment at 100-550 ^about C.

According to the invention, hydrothermal treatment is carried out simultaneously with the impregnation of the carrier with an aqueous solution containing nickel compounds with a nickel concentration of 4.0-20.0 wt. based on nickel at 40-100 ^{° C} for 0.5-5.0 hours with stirring, followed by heat treatment of the product at 100-550 ^{° C} for 0.5-5.0 hours.

In this hydrothermal treatment is carried out with water or an alkaline or acidic aqueous solution at 40-100 ^{° C} for 1-5 hours with stirring, followed by calcination.

The latter is carried out at 200-900 ^about With for 0.5-5.0 hours

 The impregnation or hydrothermal treatment of the support is carried out with an aqueous solution containing a nickel compound selected from the group: nickel nitrate, ammonia-carbonate or ammonia-nitrate complex of nickel.

In addition, the heat treatment of the carrier is carried out at 100-550 ^about C for 0.5-5.0 hours

 According to the invention, the aqueous solution of the nickel compound further comprises promoters and / or activators.

 The advantage of this method is the provision of effective conversion of hydrocarbon materials with high activity of the catalyst and its resistance to carburization.

 The essence of the proposed technology is as follows.

 Upon receipt of the catalyst at the stage of hydrothermal treatment, a partial hydration of the surface of the carrier occurs with the formation of a layer of hydration products with a very high specific surface on a dense ceramic substrate. Subsequent calcination of the carrier leads to an even greater development of the surface of the carrier due to the partial or complete removal of hydrated moisture. Thus, a layer of products with a highly developed microporous surface with high wettability is formed on a dense sintered ceramic substrate. The combination of these factors leads to the fact that in the process of impregnation of the support with a nickel-containing compound, nickel stabilizes on the surface in a highly dispersed state, providing a high specific catalytic activity of the catalyst. The above properties of the catalyst ensure its high activity with a relatively low nickel content. The ability to reduce the Nickel content in the catalyst allows you to apply the required amount of Nickel in the process of a single impregnation of the media, which greatly simplifies the technology of preparation of the catalyst. The presence of alkaline earth metal oxides (Ca, Ba, Sr) in the catalyst carrier in the declared amounts leads to the fact that the nickel-containing phase located on the active surface is a complex comprising alkaline-earth metal ions. A characteristic feature of this complex is its high ability to suppress the formation of carbon during the conversion of hydrocarbons. As a result, the proposed technology for the preparation of a catalyst for the conversion of hydrocarbons provides a catalyst not only with high activity, but also with high resistance to carbonization, and the preparation technology is simple and economical.

 The catalyst obtained by the proposed technology when working in the process of steam, carbon dioxide or steam carbonate conversion of hydrocarbon feeds provides an equilibrium methane content in the final gas mixture at an oxidizer / carbon ratio in the reaction mixture 20-30% lower than generally accepted.

 The technology is implemented as follows. According to the methods of examples 1-3, a hydrocarbon feed conversion catalyst is prepared. According to the method of example 4, the process of conversion of hydrocarbons using the claimed catalyst.

PRI me R 1. The mixture to obtain a carrier for the catalyst is prepared by mixing zirconium hydroxide and barium carbonate in a ratio of 1.6: 1 wt. including the molar ratio of ZrO ₂ : BaO 2: 1. Based on the obtained mixture, carrier granules are formed in the presence of a binder of a 10% solution of polyvinyl alcohol. Calcination of the pellets produced at 1500 ^{° C} for 4 hours. Then, the pellets are subjected to a hydrothermal treatment at ¹⁰⁰ ° C for 5 hours in aqueous neutral medium with stirring, and then they are calcined at 700 ^{° C} for 1 hour. After that the finished carrier impregnated heated ^to 85 ° C with a solution of nickel nitrate with a Ni concentration of 51 g / l, and heat-treated at 550 ^{° C} for 1 hour. The thus obtained catalyst with a nickel content of 0.9 mass%
PRI me R 2. The mixture to obtain a carrier is prepared by mixing aluminum oxide and calcium hydroxide in a ratio of 8.3: 1 wt.h. parts respectively. The molar ratio of Al ₂ O ₃ : CaO 6: 1. Based on the resulting mixture, granules are formed in the presence of a binder. Calcination of the pellets is carried out at ¹⁴⁰⁰ ° C for 1 hour. The fired pellets are subjected to a hydrothermal treatment with an aqueous solution containing nickel nitrate in a concentration of 12 wt. in terms of nickel, for 2 hours with stirring at 100 ^about C, after which the granules are calcined at 400 ^about C for 1 h to obtain a catalyst containing 6.5 wt. nickel.

PRI me R 3. The mixture to obtain a carrier is prepared by mixing alumina, calcium oxide and barium oxide in a ratio of 15: 4: 1 wt.h. respectively. The molar ratio of alumina to alkaline earth metal oxides is 1.9: 1. On the basis of the obtained mixture, they are formed in the presence of a carrier binder granule. Calcination of the pellets produced at 1450 ^{° C} for 3 hours. The calcined granules are subjected to a hydrothermal treatment with an aqueous solution containing nickel nitrate in a concentration (of nickel) 8 wt. for 2 hours with stirring and a temperature of 100 ^about C. After which the granules are calcined at 500 ^about C for 1 h and soaked in a heated solution containing nickel nitrate with a concentration (on nickel) of 20 g / l, with stirring. Then the granules are subjected to heat treatment at 500 ^about C for 1 h to obtain a catalyst containing 3.3 wt. nickel oxide (catalyst 8 of table 1).

 The data obtained by the method of example 3 sample catalyst are presented in table. 1.

PRI me R 4. Purified from natural gas composition, vol. CH ₄ 98.0; C ₂ H ₆ 0.4; C ₃ H ₈ 0.2; CO ₂ 0.1; 1.3% inerts at a temperature of 370 ^{° C,} pressure of 4.0 MPa in an amount 38000-43000 Nm ³ / h cmeshivaetsya with heated steam with a pressure of 4.1 MPa and a temperature of 380 ^{° C} in an amount of 95-115 t / h. The molar ratio of steam: gas is 3.0: 1. The resulting steam-gas mixture is heated to a temperature of 500 ^{° C} and enters the reaction tube heated tube furnace filled with a catalyst prepared according to the procedure of Example 3. The tubes at a pressure of 3.0 MPa, a space velocity of 2500 h ^-1 (natural gas) and The temperature at the outlet of 770-830 ^о С is the process of steam conversion of hydrocarbons. Dry converted gas after exiting the furnace tubes has the following composition, vol. CH ₄ 4-6; CO 9-12; CO ₂ 7-10; H ₂ 70-72 and is used in further processing for the synthesis of ammonia.

 The data on the technology of the hydrocarbon conversion process are presented in table. 2.

The proposed composition and technology for the preparation of the catalyst, in comparison with the known, allows to obtain the following advantages:
to obtain a catalyst that combines high activity, increased resistance to carbonization and the stability of physico-mechanical characteristics, which determines the effectiveness of its use;
to provide the above properties of the catalyst with not more than two times the application of the active component in the process of preparation of the catalyst, which significantly increases the economic efficiency of the production of catalyst;
to ensure equally high performance characteristics of the catalyst in the range of active component content of 0.3-10.0 wt. which, if necessary, can significantly reduce nickel consumption and thereby reduce the cost of synthesis gas production and increase the economic efficiency and environmental friendliness of the production of conversion catalysts.

Claims (10)

 1. The method of conversion of hydrocarbon feedstock, comprising reacting the feedstock with an oxidizing agent in the presence of a nickel-containing catalyst at elevated temperature, characterized in that the reaction is carried out in the presence of a catalyst containing 0.3 to 10.0 wt.% Nickel deposited on a carrier containing aluminum oxides and / or zirconium with the addition of metal oxides from the group of: calcium, barium, strontium with a molar ratio of aluminum and / or zirconium oxides and additive oxides equal to (1 - 6): 1, respectively.  2. The method according to claim 1, characterized in that water vapor, carbon dioxide or mixtures thereof are used as an oxidizing agent. 3. The method according to claims 1 and 2, characterized in that the interaction is carried out at 450 - 950 ^o C, a pressure of 0.1 - 4.0 MPa and a volumetric rate of hydrocarbon raw materials of 2000 - 4000 h ^{- 1} . 4. A method of obtaining a catalyst for the conversion of hydrocarbon feedstocks, comprising preparing a support by mixing the starting oxides or metal compounds, forming, hydrothermally treating, calcining, then impregnating the support with a solution containing nickel compounds, and heat treating, characterized in that the mixture of the starting aluminum oxides and / or zirconium or their compounds with the addition of oxides from the group of: calcium, barium, strontium or a mixture thereof or their compounds is carried out in a molar ratio (1-6): 1, respectively, after which the resulting mixture is molded and calcined at 1350 - 1500 ^o C for 1 to 8 hours, then subjected to hydrothermal treatment and the resulting product is calcined at 120 - 900 ^o C and impregnated with a heated solution containing nickel compounds with a concentration of 20 - 150 g / l in terms of on nickel, followed by heat treatment at 100 - 550 ^o C. 5. The method according to claim 4, characterized in that the hydrothermal treatment is carried out simultaneously with the impregnation of the carrier with an aqueous solution containing nickel compounds with a nickel concentration of 4.0 - 20.0 wt.% In terms of nickel, at 40 - 100 ^o C in during 0.5 to 5.0 hours with stirring, followed by heat treatment of the product at 100 - 550 ^o C for 0.5 to 5.0 hours 6. The method according to claims 4-5, characterized in that the hydrothermal treatment is carried out with water or an alkaline or acid solution at 40-100 ^° C for 1-5 hours with stirring followed by calcination. 7. The method according to claim 6, characterized in that the calcination of the product is carried out at 200 - 900 ^o C for 0.5 to 5.0 hours  8. The method according to claims 4 to 7, characterized in that the carrier is impregnated or hydrothermally treated with an aqueous solution containing a nickel compound selected from the group: nickel nitrate, ammonia-carbonate or ammonia-nitrate complex of nickel. 9. The method according to PP.4 - 8, characterized in that the heat treatment is carried out at 100 - 550 ^o C for 0.5 to 5.0 hours  10. The method according to PP.4 to 9, characterized in that the aqueous solution of a nickel compound further comprises promoters and / or activators.

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