SU550173A1 - The method of preparation of the catalyst for the pyrolysis of hydrocarbons - Google Patents

Description

one

The invention: relates to the field of catalysts, in particular to a method for preparing catalysts for the pyrolysis of hydrocarbon feedstocks.

A known method of preparing a catalyst for this process is by applying an alkali or alkaline earth metal vanadate to the pre-ground and acid-treated carrier.

The closest in technical essence is the way in which the mixture containing alumina and silicon is fired at 1380-1400 ° C, then it is cooled, crushed, mixed with a burnable additive and calcined at 1500 ° C.

However, the catalyst obtained has an insufficient mechanical strength of 600 kg / cm and activity, namely, during the pyrolysis of virgin Romashkinskaya gasoline at a temperature of 750 ° C, a flow rate of 5 hours, such as ethylene, is 29.5 wt. %, propylene - 9.4 wt. %

To prepare a catalyst with higher mechanical strength and activity according to the proposed method, the mixture is heat treated at 1800–1900 ° C and calcined at 450–650 ° C for 8–10 h in a stream of inert gas, for example nitrogen, with the addition of 0.1 -10% of oxygen and then at a temperature of 950-1400 C for 12-15 hours in a stream of inert gas with the addition of 1.0-20% oxygen. 80–94% for catalyst preparation

a-alumina is mixed with 5-20% silica and the mixture is fused in an electric furnace at a temperature of 1800-1900 ° C. The alloy is cooled and ground to a powder with a particle size of 200-250 microns. The resulting powder in the amount of 70-80% is mixed with 10-20% of low-melting clay, with 10% dextrin and 1-5% of sawdust in a drum mixer, and then the mixture is fed into a screw mixer, where water is added to obtain a thick moving mass. This mass is passed through a molding machine to obtain balls of regular spherical shape with a diameter of 3-7 mm. They are dried at a temperature of 100-150 ° C, and then calcined in two stages

in the current of inert gas with the addition of oxygen supplied at a rate of 3-10 l / h, at atmospheric or elevated pressure. In the first stage, the calcination is carried out at a temperature of 450-650 ° C, the concentration of oxygen in the inert

nom gas 0.1 -10 vol. % for 10 h, in the second - at 950-1400 ° С, oxygen concentration in an inert gas is 10-20 vol. % for 15 h with temperature rise at the first-stage at a rate of 20 ° С / h, at the second - 30 ° С / h. Before operation, the catalyst is activated by blowing air at 750 ° C at a rate of 3-10 l / l of catalyst for 3 hours. The sawdust burns out, and large voids and pores are created in the catalyst balls. Instead of sawdust, polystyrene powder and other organic compounds and polymers can be used, easily ignored when calcining the catalyst. The resulting catalyst has the following, its chemical composition, weight. %: a -AbOz80-94 SiOa5-20 ReaOz0,01-0,15 TiOa0,01-0,25 MgO0,01-0,15 CaO0,01-0,15 NaO0,01-0,15 KzO0,01-0 , 15 Its specific surface is less than 1, the porosity is about 50%, the fill weight is 1-1.1 g / cm, the strength is more than 50 kg / ball. Example 1. 85 g are mixed with 15 g of SiO2, the mixture is melted in a tunnel electric furnace at a temperature of 1900 ° C. The alloy is cooled to 20 ° C, crushed to a powder with a particle size of 230 μm. 75 tons of the obtained powder are mixed with 10 g of low-melting clay, 10 g of dextrin and 5 g of sawdust in a drum mixer, then the mixture is fed into a screw mixer, where water is added to obtain a thick moving mass. This mass is passed through a molding machine to obtain balls of regular spherical shape with a diameter of 6 mm, then they are dried at 110 ° C and calcined in a stream of nitrogen under a pressure of 2 atm in two stages. First, calcined at a temperature of 450-650 ° C in a stream of nitrogen with an oxygen content of 0.5 vol. % for 8 h with a gradual rise in temperature, then at a temperature of 1000-1400 ° C in a stream of nitrogen with an oxygen content of 12 vol. % for 12 hours. The resulting catalyst has the following, its chemical composition; weight. %: a-MgOz80.25 SiOz19 RegOz0.05 TiOa0.2 CaO0.1 MgO0.15 NazO0.01 KgO0.15 This catalyst is used for the pyrolysis of Tyumen oil p / 0.874, containing 1.5% of its sulfur, asphaltenes 2, 2%; fractional composition, vol .-%: f-cancer with t. Kip. up to 200 ° C - 18.8%, with t-kip. 200-300 ° С-16.2%, above 300 ° С-65.0%. The process is carried out in a protocha laboratory installation with a tubular reactor (volume 30 cm) at a temperature of 750 ° C, supplying 50% water vapor by weight of the raw material and a bulk flow rate of the raw material for 1.5 hours. The yield of gaseous products, calculated as missed raw material, 63 , 8 weight. %, including: ethylene 29.1, propylene 12.8, divinyl 5.0, oxide and carbon dioxide (in total) less than 0.2%. During 1000 hours of experience, the activity of the catalyst remained constant. Example 2. A mixture of 95 g with 5 g of SiOg is fused in a tunnel electric furnace at a temperature of 1850 ° C. The alloy is cooled to 20 ° C, crushed to a powder with a particle size of 250 microns. The resulting powder, in an amount of 85 g, is mixed with 10 g of low-melting clay, 3 g of dextrin and 2 g of polystyrene in a drum mixer, then the mixture is fed into a screw mixer, to which water is added. The resulting mass is passed through a molding machine to produce balls of 6 mm, they are dried at a temperature of 115 ° C and calcined in a stream of nitrogen under a pressure of 2 atm in two stages: first, at a temperature of 450-650 ° C in a stream of nitrogen with an oxygen content of 9.5 . % for 10 hours with a gradual rise in temperature, then at a temperature of 950-1350 ° C in a stream of nitrogen with an oxygen content of 18.5 vol. % within 15 hours. Chemical composition of the obtained catalyst, wt. %: a-LO380-25 SiOa19 ReaOz0.05 TiOs0.2 CaO0.1 MgO0.15 NasO0.01 KgO0.15 In the presence of this catalyst, the Tyumen oil of Example 1 is pyrolyzed under the conditions of this example p. bulk rate 4h. The yield of gaseous products (based on the leaked oil is 65.7% by weight, including ethylene 25.1, propylene 12.1, divinyl 4.2, carbon monoxide and carbon dioxide (in total) 0.45% Example 3. The first gasoline of Romashkinskaya oil, p | ° 0.716, bp 40–180 ° C, 0.07% sulfur content is subjected to pyrolysis at a temperature of 750 ° C, a space velocity of 5 hours and a supply of 25% water vapor from the weight of the raw material. A catalyst containing, in wt.%: ABOz 80.25, SO2 29, RegOz 0.05, TiO2 0.2, CaO 0.1, MgO 0.15, NasO 0.01, CgO 0.15 Its preparation is described in Example 1. The gas outlet is 89.5 wt.% (from raw materials), including: carbon monoxide and carbon dioxide 0.1, hydrogen 0.9, methane 14.2, ethane 2.0, ethylene 38.8, propane 0.8, propylene 17.8, butylenes + divinyl 14.9; liquid products 16.5, coke 0.3, loss 1.0. In the implementation of the pyrolysis of light naphtha with bp 30-88 ° C (df 0,6455, the content of sey 130 ppm) catalyst (86.55%) + K2O (13.45%) prepared according to the well-known method under optimal conditions, at 750 ° С, space velocity 5, supply of 150% water vapor by weight of the raw material, yield of ethylene, propylene, and butylips divinyl (in total) is significantly less and amounts to 37.5, 14.5 and 8 weight respectively. % of raw materials. The yield of carbon oxides and coke is greater - 1.8 and 2.4 weight, respectively. % of raw materials. It should be noted that in the known method, a significantly more favorable composition of the raw materials for pyrolysis and an increased (almost 7 times) amount of water vapor are used.

The catalysts prepared according to the known and proposed methods were tested under the same conditions of a laboratory installation during the pyrolysis of virgin Romashkinskaya gasoline at 750 ° C, 5 with a supply of 25% water vapor. Some indicators of the quality of the catalysts and the results of comparative tests of their activity are shown in the table. Thus, the proposed method allows to obtain an active catalyst suitable for processing light and heavy hydrocarbon feedstocks (individual hydrocarbons, gasoline, kerosene, gas oil, fuel oil, oil, etc.), which has a high mechanical

strength, regular spherical shape, small specific surface area, low content of oxides Ti, .M.g, Ca, K, Na, Fe, which allows to significantly increase the productivity and reliability of the process and reduce

catalyst cost.

Claims (1)

Invention Formula A method of preparing a catalyst for the pyrolysis of hydrocarbon feedstock by heat treatment of a mixture containing alumina and silica, cooling and grinding the catalyst mass, mixing with burned out, addition and subsequent calcination, characterized in that, in order to prepare a catalyst with higher mechanical strength and activity , heat treatment of the mixture is carried out at 1800-1900 ° C and calcining is carried out at 450-650 ° C for 8-10 hours in a stream of inert gas, for example nitrogen, with the addition of 0.1-10% oxygen, then at 950-1400 ° C for 12-15 hours in a stream of inert gas with the addition of 10-20% oxygen.