Catalyst for oxidation of sulfur compounds

 

(57) Abstract:

The invention relates to the production of heterogeneous catalysts for liquid-phase oxidation of sulfur compounds in the gas emissions and wastewater and can be used in oil refining, petrochemical, pulp and paper and chemical industries. The essence of the invention: catalyst for oxidation of sulfur compounds it contains, wt%: pyrite cinder 10 - 15; chromium oxide (VI) 3 - 5; copper oxide 5 - 10; oxide of vanadium (V) 3 - 5; petroleum coke 7 - 10; zinc oxide 5 - 10; medium-clay - rest. 6 table.

The invention relates to the production of heterogeneous catalysts for the oxidation of sulfur compounds in a gas-liquid environment and can be used for cleaning flue gases from sulfur dioxide power plants, mercaptans, hydrogen sulfide, sulfur dioxide contained in the gas emissions of boilers recycling in the pulp and paper industry, and can also be used for water purification from hydrogen sulfide and mercaptans in the pulp and paper, gas, refining, petrochemical and mining industries.

Known heterogeneous catalysts for liquid-phase components, wt.

Pyrite cinder 30-40

Polyethylene Else

The catalyst has a relatively high catalytic activity in water purification from hydrogen sulfide. Thus, the depth of wastewater to hydrogen sulfide at concentrations of 500-800 mg/DM3varies between 95-97% at the time of oxidation 15-20 min, temperature 90aboutC and a pressure of 0.3 MPa.

The closest solution to the technical essence and the achieved effect similar tasks catalyst for liquid-phase oxidation of sulfur compounds containing pyrite cinder, a copper oxide and a carrier of polyethylene, with the following content, wt.

Pyrite cinder 30-40

The copper oxide 3-7

Polyethylene Else

The catalyst has high catalytic activity as in wastewater and gas emissions in the form of a gas-liquid mixture in the oxidation of hydrogen sulfide, mercaptans and mixtures thereof. In the wastewater depth treatment to remove hydrogen sulphide and mercaptans, containing mercaptans 150 mg/l hydrogen sulfide 680 mg/l is 93-96% of the Time, the oxidation of 3 min, a pressure of 0.3 MPa, the temperature oxidation 90aboutC. Depth treatment of gas emissions in the form of gas-liquid mixtures containing up to 8100 mg/m33, hydrogen sulfide, at least 175 mg/m3that significantly exceed the MPC. The cleaning gas mixture was carried out at a temperature of 80-90aboutS, i.e. with a mandatory cooling gas-liquid mixture to the specified temperature.

Cleaning gas-liquid mixture having a temperature 110-118aboutWith, for example exhaust gases of the pulping process, the composition of which is specified above, is not possible because the melting point of the catalyst containing the medium polyethylene is about 100-110aboutC. In this regard, the use of this catalyst in the purification technologies like gas emissions requires more complex hardware design process and process temperature control. In the artificial lowering of the temperature reduces the reaction rate and degree of treatment increases the response time.

Significantly reduce the time of oxidation and to increase the depth of oxidation of hydrogen sulfide, mercaptans and sulfur dioxide in the treated gas will allow the use of the catalyst containing pyrite cinder, vanadium oxide, zinc oxide, copper oxide, chromium oxide, petroleum coke and medium clay, with the ka 5-10

The chromium oxide 3-5

The copper oxide 5-10

Petroleum coke 7-10

Clay Rest

The hallmark of the invention is the composition of the catalyst components and their relationship. The use of this catalyst allows the cleaning process at any temperature of the purified gas.

The catalyst according to the invention, in comparison with the prototype, has a high catalytic activity and thermal stability, which allows you to clean highly concentrated gases containing mercaptans, hydrogen sulfide, and sulfur dioxide, while reducing the oxidation time up to 0.5-1 min at any high initial temperature of the gas.

The specified catalyst also has high mechanical strength and hydrolytic resistance. The main function of the catalytically active components perform made the oxides of metals of variable valency, as well as those elements and minerals that are contained in the pyrite cinder, wt. SO33,67; Fe2O361-62; FeO 4.0 to 4.5; CaO 1.0 to 1.5; Al2O32,5-3,1; SiO23,5-4,1; CuO 2,5-2,8; MgO 0,2-0,3; K2O 0,35-0,40; Na2O 0,2-0,3; trace elements wt. Br 0,0300; Pb 0,0006; C 0,0020; Mn 0,0076; Ni 0,0009; V 0,0035, glazed clay, wt. Fe

The results of x-ray analysis:

SiO quartz.

hydromica: Al(OH)2Al SiO3O10}n< / BR>
H2O; k Al(SiO2)4(OH)2< / BR>
Feldspar

(albite): Na2O Al2O36 SiO2< / BR>
Montmorin-

lonit: 2 Al2Si4O10(OH)2n H2O

Ciolina: Al2O32SiO22 H2O, And also the elements in petroleum coke, wt. SiO29.5 to 10.1; TiO20,5-0,6; Al2O32,5-4,3; Fe2O36,3-7,1; MnO20,02-0,03; MgO 1,2-1,3; CaO 6,5-7,0; Na2O 0,01-0,03; K2O OF 0.3-0.4; P2O50.18 to 0.2.

The spectral composition of the ash of petroleum coke, wt. Bi 0,01-0,03; Cr 0,001; Mn 0,02-0,03; Fe 0,001-0,002; V 0,001; Nio 0,003-0,006; Mo 0.001 To 0.01; Cr 0,003; Cu 0,002-0,005; Ag 5-10; Co 0,01-0,05.

The catalyst is prepared by mixing and grinding in a vibrating mill media-clay clay, pyrite cinder, coke, vanadium oxide, zinc oxide, copper oxide, chromium oxide. In a homogeneous mixture of the above components are dispersed composition is not higher than 500 add water and in a Z-shaped mixer with thorough stirring to prepare a pasty catalyst mass which is formed into pellets in a vacuum press, which provalivajut at a temperature of 20-25aboutC, and C is -1200aboutC for 15 minutes

Calcination of the catalyst provides high mechanical strength, hydrolytic resistance and stable work in the process of gas-liquid oxidation of sulfur compounds due to the formation of different spinel-type: uFe2O4, CuCr2O4, FeCr2O4, ZnV2O4, FeV2O4, FeAl2O4, CuV2O4, CuAl2O4, Cu2Al2O4. Mechanical wear of the granules of the catalyst does not reduce the activity of the catalyst during operation as a result of updating the surface and involvement in the process of new active particles located in the mass of the catalyst. High catalytic activity and stability of the proposed catalyst is maintained at the specified ratio of active components and media. Reducing the number of active components in the mass of catalyst reduces the catalytic activity and stability of catalyst, as well as mechanical strength. The increase in the number of active components leads to the violation of the integrity of the structure of the catalyst, the catalyst becomes or fragile or melts and becomes not active.

P R I m e R 1. Catalysate else prepare by mixing, grinding on a vibratory mill to disperse the composition is not higher than 500 for 8 hours a Homogenous mixture of the above components are loaded into the Z-shaped mixer where water is added in the amount of 37-40 wt. carefully stirred for 60-90 min to obtain a pasty mass. The cooked mass is formed into pellets in a vacuum press at a pressure of 0.8 MPa, followed by pressing on the mouthpiece with a force of 18 to 20 MPa. The average density of the granules of pressata is 2.1-2.2 g/cm3. After 24-36 h wilting in the air granules are calcined at a temperature of 500-530aboutC for 4 h under high temperature 120-130aboutWith in an hour. After calcination, the catalyst is subjected to firing at a temperature of 1100-1200aboutC for 15 minutes

Similarly prepare a catalyst containing pyrite cinder, petroleum coke, vanadium oxide, zinc oxide, chromium oxide, copper oxide and clay in different mass ratio. For studies of the proposed catalyst obtained in the form of granules size: height granules 10-15 mm, outer diameter 7-10 mm, All of the thus obtained catalysts were tested in the processes of purification of gas emissions in the form of a gas-liquid mixture from the process WARC is a, and wastewater, in particular condensates from the evaporation of black liquor containing hydrogen sulfide and mercaptans.

P R I m m e R 2. Experiments on determination of the catalytic activity of the proposed catalyst for selecting the optimal composition was performed in a plant for the purification of gas emissions in the form of a gas-liquid mixture from the pulping process on the Baikal pulp and paper mill, which on average contain mercaptans 7100 mg/m3and hydrogen sulfide 2540 mg/m3. As the absorbing solution used condensate, which was obtained by cooling this gas-liquid mixture on the catalyst surface. The experiments were conducted as follows: in metal column was loaded catalyst prepared according to example 1 in the amount of 100 g, the first poured 500 ml of the above condensate pH 8.5, which is then circulated with the speed of 0.04 m/s

The gas to be cleaned with a speed of 1 m/s was applied parallel with the air, the speed of 0.25 m/s, at a temperature absorbing solution 95-115aboutC, a pressure of 0.3 MPa and time of oxidation of 0.5 minutes

To assess the degree of purification of gas emissions at the outlet of the column was performed determination of residual concentrations in the LASS="ptx2">

P R I m e R 3. To determine the stability of the proposed catalyst in a continuous mode, conducted the experiments in example 2. The speed of circulation of the absorption solution was 0.04 m/s, the flow rate of the purified gas 1.0 m/s, air 0.25 m/s the temperature of the absorbing solution 95-115aboutWith the pressure of 0.3 MPa. The catalyst was tested in a continuous mode installation for 25 h at cleaning gas emissions from the pulping process on the Baikal pulp and paper mill. The concentration of mercaptans in the original cleaned gas in the period of experience ranged 6180-7800 mg/m3hydrogen sulfide 2200-3600 mg/m3.

The data obtained are presented in table. 2.

P R I m e R 4. Experiments on determination of the catalytic activity of the proposed catalyst in the process of flue gas of thermal power plants from the sulfur dioxide was carried out according to example 2. The concentration of sulfur dioxide in the treated flue gas ranged from 1200-1500 mg/m3. The gas to be cleaned with a speed of 1 m/s was applied to the column, which was initially filled with 560 ml of water, and then it was circulated with the speed of 0.04 m/s in countercurrent to the clean gas. Oxidation of the sulfur dioxide was carried out with Ted and the output was determined by the content of sulphurous anhydride by known methods (see A collection of methods for determining the concentration of pollutants in industrial emissions. Leningrad, Gidrometeoizdat, 1987, H. 1, S. 67).

The data obtained are presented in table. 3.

P R I m e R 5. To determine the stability of the proposed catalyst (composition in table. 2) in continuous mode conducted cleaning of the flue gases from sulfur dioxide in example 4, for 300 hours the Results are presented in table. 4.

P R I m e R 6. The use of the catalyst enables the cleaning process condensates at a higher temperature, i.e., the condensate is not necessary to cool before applying to the column oxidation. Testing of the catalyst for purification of condensate was carried out according to the following procedure.

300 ml of condensate evaporation of black liquor with the content of 356 mg/DM3hydrogen sulfide and 180 mg/DM3mercaptans, pH 8.5 was oxidized in the presence of 30 g of the catalyst produced according to example 1. Granules of the catalyst (d 3-5 mm) were loaded into a metal reactor with recurring action thermostatic water jacket, a dispersant (porous plate) in the lower part of the reactor, an exemplary pressure gauge for monitoring the operating pressure. The air was applied from a container through rebola of hydrogen sulfide. Sulfur compounds were oxidized in a static mode at a temperature of 90-95aboutC, a pressure of 0.3 MPa at a flow of 5 l of air per 1 liter of purified condensate. Every 30 min, a sample was taken for determination of the degree of oxidation of sulfur compounds. The results obtained are presented in table. 5. In table. 6 presents the results to determine the stability of the catalyst in the purification process condensates from the evaporation of black liquor.

Experiments on determination of the stability of the catalyst in the purification process condensates were conducted by the method, which is given in example 6 except that the condensate in the column was applied continuously at a rate of 150 ml/min

Thus, the proposed catalyst has a higher activity compared with the prototype, in similar conditions it is possible to provide the degree of purification of up to 96% while in the case of the catalyst of the prototype purification efficiency is 91% the Use of the catalyst in the technology of flue gases from sulfur dioxide will allow to solve a very important environmental problem in the heat.

CATALYST FOR OXIDATION of SULFUR COMPOUNDS containing pyrite cinder, a copper oxide and a carrier, characterized in that C media clay in the following ratio of components, wt.

Pyrite cinder 10 15

The chromium oxide (YI) 3 5

The copper oxide (II) 5 10

Vanadium oxide (Y) 3 5

Petroleum coke 7 10

Zinc oxide 5 10

Clay Rest

 

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