RU2774997C1 - Method for obtaining active carbon materials - Google Patents

Abstract

FIELD: material engineering.

SUBSTANCE: invention relates to a method for producing a carbon porous material, which is carried out as follows: the feedstock, as which tar, asphalt, heavy shale resin, heavy catalytic cracking gas oil, is subjected to delayed coking at a temperature of 495 to 505°C and an overpressure of 1.5 to 3.5 atmg to obtain petroleum coke, then the resulting petroleum coke is crushed and mixed with potassium hydroxide powder in a mass ratio of 3: 1, carbonation of the mixture is carried out at a temperature from 745 to 755°C, next is washing with a hydrochloric acid solution with a concentration of 0.8 to 1.2 M, then with water to a neutral pH value of the washing waters, after that drying at a temperature of 105 to 120°C to obtain a carbon porous material with a specific surface area of 800 to 2300 m²/g.

EFFECT: expansion of the range of methods for obtaining active carbon materials.

1 cl, 4 ex, 1 tbl

Description

The invention relates to the oil refining industry, in particular to a method for producing active carbon materials (CM) from delayed coking petroleum coke, and can be used to produce highly active sorbents and carbon carriers for catalysts in the oil, gas chemical and other industries. Active carbon materials are obtained by activating petroleum coke with potassium hydroxide in an inert atmosphere at a temperature of 745-755°C.

There is a known method for producing nanostructured carbon material (RF Patent No. 2206394, publ. 06/20/2003) by oxidative sulfonation of carbon material with sulfuric acid in the presence of a nitric acid salt, followed by melting in the presence of group I metal hydroxides to completely decompose sulfonic acids and obtain phenolates. The resulting product is subjected to carbonization at 600-1000°C in an inert atmosphere, and then washed with distilled water. The resulting product has a high specific surface area (3000-4000 m ² /g) and unique adsorption properties.

The disadvantages of this method are the low yield of the target product - about 20%, caused by intense oxidation reactions in the presence of a strong acid, and the need to use a large number of reagents to activate the surface of the carbon material.

A known method for producing microporous carbon sorbents (RF Patent No. 2436625, publ. 20.12.2011), which includes the stages of grinding birch wood to a particle size of 2-3 mm, their carbonization in an inert atmosphere at 300-800°C with holding at the final temperature 30 min, activation in an inert medium in the presence of potassium hydroxide, taken in a mass ratio of coal : alkali equal to 1:3, at 800°C for 1 h and washing the obtained carbon materials first with a solution of hydrochloric acid, then with distilled water. The resulting carbon adsorbent has a specific surface area of about 1023 m ² /g.

The disadvantages of this method are the need for preliminary carbonization of raw materials, low specific surface area of the resulting carbon material, determined by the type of raw materials used - birch wood.

A known method for producing active carbons from aromatic carboxylic acids (US Patent No. 3817874, publ. 06/18/1974), including preheating of the source material in two stages, first to a temperature of 200-275°C with holding at the final temperature for 1-4 hours and subsequent heating to 350-600°C with holding at the final temperature for 15-45 minutes. The resulting intermediate material is then impregnated with a concentrated solution of an alkali or alkaline earth metal oxide or hydroxide, after which the solvent is evaporated. Activation of the carbon product is carried out in the presence of CO ₂ at a temperature of 600-800°C for 0.5-1.5 hours. The resulting product has a surface area of 100-1300 m ² /g.

The disadvantage of this method is the need to carry out the process in several stages at different temperature conditions, which complicates the process of obtaining the activated material and increases the process time. The specific surface area of the resulting carbon material is low because CO ₂ is used as an activating agent.

A known method for producing activated carbon material (US Patent No. 4082694, publ. 04/04/1978) from crushed coal, coal coke, petroleum coke or mixtures thereof in the presence of aqueous potassium hydroxide at two temperatures. The method includes grinding the feedstock to sizes less than 10 mesh, mixing it with solid potassium hydroxide containing at least 2% water, in the ratio carbon material : alkali = 1 : 3. The resulting mixture is heated with stirring in an inert atmosphere, first to 600- 900°C and kept at the final temperature from 15 minutes to 13 hours, then heated to 1300-1800°C and kept at this temperature from 20 minutes to 4 hours. The resulting product is then cooled, washed with water to remove inorganic substances, and dried. The activated carbon material has an effective surface area in excess of 2300 m ² /g.

The disadvantages of this method is the activation process in two stages and the high temperature of activation of the product in the second stage, which reduces the yield of the target product and increases the process time to obtain the target product. The use of coal in the charge increases the ash content of the obtained activated carbon material, which reduces the quality of the finished product.

A known method for producing a carbon sorbent from a carbon-containing material (RF Patent No. 2558590, publ. 08/10/2015), taken as a prototype, including joint grinding of a carbon-containing material with alkali or alkali metal carbonate in a mass ratio of KOH : UM = 1 : 1 - 3 : 1 , carbonization of the resulting mixture, pressing in a mold under a pressure of 400 MPa into tablets, their subsequent heating to 800 ° C in a stream of nitrogen and holding at this temperature for 2 hours, washing the product with hydrochloric acid, and then with water until the washing pH is neutral water. The yield of active carbon material is 45-60%, and the specific surface area varies in the range of 780-2300 m ² /g.

The disadvantages of this method are the long activation time of the UM and the need to press the raw material under high pressure.

The technical result is to obtain an active carbon material with a high surface area.

The technical result is achieved by the fact that the feedstock, which is used as tar, asphalt, heavy shale tar, heavy catalytic cracking gas oil, is subjected to delayed coking at a temperature of 495 to 505°C and an overpressure of 1.5 to 3.5 atm. to obtain petroleum coke, with a yield of volatile substances less than 9%, the carbonization of the mixture is carried out at a temperature of 745 to 755 ° C, then washed with a solution of hydrochloric acid with a concentration of 0.8 to 1.2 M, then with water until a neutral pH value of the washing water, then dried at a temperature of 105 to 120°C to obtain a porous carbon material with a specific surface area of 800 to 2300 m ² /g.

The method is carried out as follows. Tar, asphalt, heavy shale tar, heavy catalytic cracking gas oil are used as feedstock for delayed coking. Raw materials are coked in a coking chamber at a temperature of 495 to 505°C and an overpressure of 1.5 to 3.5 atm. The resulting petroleum coke with a low volatile matter yield of less than 9% is unloaded into a receiving tank and then placed in a mill. In a mill, petroleum coke is crushed to a particle size of less than 100 microns. Then crushed petroleum coke is placed in a mixing tank and mixed with potassium hydroxide powder in a mass ratio of potassium hydroxide : coke = 3 : 1. The resulting mixture is placed in a high-temperature furnace and carbonized at a temperature of 745 to 755°C and a heating rate of 5 to 6 °C/min under an inert nitrogen atmosphere, holding at the final temperature for 55 to 65 minutes. After heating, the product is cooled in an oven under an inert nitrogen atmosphere to room temperature. Then the CM is unloaded into a receiver and washed first with a solution of hydrochloric acid with a concentration of 0.9 to 1.1 M, then with water to remove acid residues from the reaction products to a neutral pH value of the washing water. Rinse water is sent to a purification and disposal unit. After washing, the CM is dried at 105 to 120°C in an oven to constant weight. The resulting porous carbon material has a high specific surface area of 800 to 2300 m ² /g.

The method is illustrated by the following examples.

Example 1. Tar is coked at a temperature of 490-510°C and an overpressure of 1.4 to 3.6 atm. The resulting petroleum coke after unloading is crushed to a particle size of less than 100 μm, mixed with potassium hydroxide powder in a mass ratio of KOH : YM = 3 : 1 and carbonized at a temperature of 745 to 755°C with a heating rate of 5 to 6°C/min. In an inert atmosphere of nitrogen with exposure at the final temperature for 55-65 minutes. After activation, the product is cooled in an inert atmosphere of nitrogen to room temperature, unloaded and washed first with a solution of hydrochloric acid with a concentration of 0.8-1.2 M, then with water to remove alkali residues from the reaction products to a neutral pH value of the washing water and drying the CM at 105-1.2 M. 120°C to constant weight. The specific surface area of the active CM, determined by the Brunauer, Emmett and Teller (BET) method, is presented in Table 1.

Example 2. Asphalt is coked at a temperature of 490-510°C and an overpressure of 1.4 to 3.6 atm. The resulting petroleum coke after unloading is crushed to a particle size of less than 100 μm, mixed with potassium hydroxide powder in a mass ratio of KOH : YM = 3 : 1 and carbonized at a temperature of 745 to 755°C with a heating rate of 5 to 6°C/min. In an inert atmosphere of nitrogen with exposure at the final temperature for 55 to 65 minutes. After activation, the product is cooled in an inert atmosphere of nitrogen to room temperature, unloaded and washed first with a solution of hydrochloric acid with a concentration of 0.8-1.2 M, then with water to remove alkali residues from the reaction products to a neutral pH value of the washing water and drying the CM at 105-1.2 M. 120°C to constant weight. The specific surface area of the active CM, determined by the BET method, is presented in Table 1.

Example 3. Heavy shale tar is coked at a temperature of 490-510°C and an overpressure of 1.4 to 3.6 atm. The resulting petroleum coke after unloading is crushed to a particle size of less than 100 μm, mixed with potassium hydroxide powder in a mass ratio of KOH : YM = 3 : 1 and carbonized at a temperature of 745 to 755°C with a heating rate of 5 to 6°C/min. In an inert atmosphere of nitrogen with exposure at the final temperature for 55 to 65 minutes. After activation, the product is cooled in an inert atmosphere of nitrogen to room temperature, unloaded and washed first with a solution of hydrochloric acid with a concentration of 0.8-1.2 M, then with water to remove alkali residues from the reaction products to a neutral pH value of the washing water and drying the CM at 105-1.2 M. 120°C to constant weight. The specific surface area of the active CM, determined by the BET method, is presented in Table 1.

Example 4. Heavy catalytic cracking gas oil is coked at a temperature of 4900-510°C and an excess pressure of 1.5 to 3.5 atm. The resulting petroleum coke after unloading is crushed to a particle size of less than 100 μm, mixed with potassium hydroxide powder in a mass ratio of KOH : YM = 3 : 1 and carbonized at a temperature of 745 to 755°C with a heating rate of 5 to 6°C/min. In an inert atmosphere of nitrogen with exposure at the final temperature for 55 to 65 minutes. After activation, the product is cooled in an inert atmosphere of nitrogen to room temperature, unloaded and washed first with a solution of hydrochloric acid with a concentration of 0.8-1.2 M, then with water to remove alkali residues from the reaction products to a neutral pH value of the washing water and drying the CM at 105-1.2 M. 120°C to constant weight. The specific surface area of the active CM, determined by the BET method, is presented in Table 1.

Table 1 - Specific surface area of active carbon material obtained using tar, asphalt, heavy shale tar, heavy catalytic cracking gas oil as delayed coking feedstock Type of raw material UM Coking parameters Furnace heating rate, °С/min UM activation temperature, °C Activation time, min Drying temperature, °C Concentration of hydrochloric acid solution, M Specific surface area of active CM, m ² /g Active UM output, % Pressure (excess), ati Temperature, °C Tar 1.4 510 5 745 65 105 0.8 2290-2066 71 1.5 500 5 745 60 110 1.0 2302-2080 78 2.5 495 6 750 55 115 1.1 1674-1702 76 3.5 505 5 755 60 110 0.9 1168-1051 72 3.6 490 6 750 65 120 1.2 1148-1027 70 Asphalt 1.4 490 6 750 65 120 1.2 1588-1420 65 1.5 495 5 745 60 110 1.0 1599-1428 70 2.5 505 5 755 60 105 0.9 1247-1168 67 3.5 500 5 745 65 115 1.1 1163-1029 69 3.6 510 6 750 55 105 0.8 1143-1011 62 Heavy shale tar 1.4 510 6 755 65 120 1.2 1012-978 69 1.5 500 6 750 60 110 1.1 1036-994 74 2.5 495 5 745 60 115 0.9 844-838 75 3.5 505 5 750 55 110 1.0 1190-1049 78 3.6 490 5 755 65 105 0.8 1155-1034 70 Heavy catalytic cracking gas oil 1.4 490 6 745 55 105 0.8 1635-1511 72 1.5 500 6 745 60 110 1.0 1677-1554 75 2.5 505 5 750 60 115 1.1 1506-1504 73 3.5 495 5 755 65 110 0.9 1383-1378 72 3.6 510 5 745 55 120 1.2 1380-1372 66

The proposed method for producing active carbon materials makes it possible to use low-quality raw materials in the process of delayed coking to obtain petroleum coke, after activation of which a highly porous carbon material with a high specific surface area is obtained. At the same time, CM obtained at a low excess pressure of delayed coking shows the best results in terms of specific surface area, which makes it a promising material for use as a sorbent or catalyst carrier. The method increases the raw material base for obtaining porous carbon materials and does not require additional carbonization stages.

Claims (1)

The method for producing carbon porous material, which is carried out as follows: the feedstock, which is used as tar, asphalt, heavy shale tar, heavy catalytic cracking gas oil, is subjected to delayed coking at a temperature of 495 to 505 ° C and an overpressure of 1.5 to 3.5 atm to obtain petroleum coke, then the resulting petroleum coke is crushed and mixed with potassium hydroxide powder in a mass ratio of 3: 1, the carbonization of the mixture is carried out at a temperature of 745 to 755 ° C, then washed with a solution of hydrochloric acid with a concentration of 0.8 to 1.2 M, then with water to a neutral pH value of the washing water, after which it is dried at a temperature of from 105 to 120 ° C to obtain a porous carbon material with a specific surface area of 800 to 2300 m ² /g.