Heterogeneous catalyst for oxidation of inorganic and/or organic compounds on polymer carrier
FIELD: oxidation catalysts.
SUBSTANCE: invention relates to manufacture of heterogeneous catalysts for the processes of liquid-phase oxidation of inorganic and/or organic compounds, including sulfur-containing ones, with air oxygen. Invention provides heterogeneous catalyst containing (i) active component (15-50%) on polymer carrier, namely polyethylene, polypropylene, polystyrene or another polymer, said active component being variable-valence metal oxides and/or hydroxides, or spinels, and additionally (ii) modifying additive (0.5-20%), namely organic bases and/or heteropolyacids, and/or carbon-containing material.
EFFECT: increased catalytic activity.
2 cl, 5 tbl, 6 ex
The invention relates to the production of heterogeneous catalysts for processes of liquid-phase oxidation of inorganic (sulfur, nitrogen, phosphate and others) and organic (PAHs, phenols, oil products and other) compounds by oxygen.
These catalysts can be used in the energy, refining, petrochemical, chemical, pulp and paper, mining and other industries for local catalytic wastewater treatment, absorption and catalytic treatment of gas emissions, biological treatment and catalytic purification of waste water, for catalytic disinfection of water in industry and utilities, as well as in some industrial processes, for example, the catalytic oxidation of sodium sulfide in the white liquor, the catalytic process intensification oxygen-alkali bleaching and other
Known heterogeneous catalyst on a medium - high-pressure polyethylene (LDPE)containing pyrite cinder - 40-50%. This catalyst has a high activity in the oxidation of sulfur, organic sulfur and organic compounds, but do not provide the selectivity /1/.
Known heterogeneous catalyst on a carrier - LDPE containing manganese oxide 23-25%, chromium oxide 3-5%, molybdenum oxide 5-7% and the led Nickel 3-5%, designed for use in the process of biochemical wastewater treatment /2/. The catalyst has a low activity and selectivity.
The closest to the achieved result is a heterogeneous catalyst on a carrier LDPE containing pyrite cinder 40-50%, phthalocyanine cobalt - 0.5 to 1.0%. The specified catalyst has a high selectivity in the oxidation of sulfur, organic and organic sulfur compounds, but it provides low activity, causing a long contact time of the cleaning process, and requires a relatively large structures and operating costs /3/.
To address these shortcomings prompted the catalyst as an active ingredient contains oxides and/or hydroxides and/or spinel metals with variable valence, and, optionally, modifying additives, which are organic bases and/or heteroalicyclic, and/or carbonaceous material on the carrier is polyethylene, polypropylene or polystyrene, or another polymer in the following catalyst components, mass %:
the active ingredient 15-50
modifying additive of 0.5-20
the media and the rest
Distinctive features of the proposed catalyst are:
the composition of the active component, to the which is a composition of oxides and/or hydroxides, and/or spinels of metals of variable valence;
- the presence of the modifying additive, which uses organic base and/or heteroalicyclic, or carbon-containing material;
along with well-known media - LDPE, you can use other polymers, in particular polystyrene, polypropylene.
The proposed catalyst, in comparison with the prototype, is more active in the process of liquid-phase oxidation of inorganic and organic compounds (oil, fatty acids, alcohols, aldehydes, ketones, phenol and its homologues and products of their oxidation), nitrogen-, phosphorus-, gray - and carbon-containing compounds (hydrogen sulfide, sulfides, sulfites, mercaptans, sulfur dioxide, oxides of nitrogen, heptyl and products of its decomposition, carbon monoxide etc) and disinfection by microflora in a wide range of initial concentrations at pH 7-12. This is based on the use of the catalyst in the process:
- wastewater and gas emissions by the method of liquid-phase oxidation and catalytic oxidation to carbon dioxide, sulfur dioxide and water;
- biocatalytic wastewater treatment;
- adsorption-catalytic purification and treatment of sewage and drinking water;
- disinfection of wastewater and drinking water;
- oxidation of sodium sulfide in the white liquor.
The catalytic activity is closely related with the adsorption activity of the catalyst surface. The preliminary stage of catalysis is the adsorption of molecules of oxygen and oxidizable substance (substrate) on the surface of the catalyst. This adsorbed oxygen molecules and the substrate, especially in the presence of polar groups in a certain way oriented to the surface of the catalyst. Emerging surface compounds are characterized by high reactivity. The increase in reactivity due to the nature of the intermediate interaction of the reactant with the catalyst.
The surface of the kata is Isadora, due to the composition of the active component, the hydrophobic properties of the media and the introduction of modifying additives, has a more specific ability to adsorb oxygen in comparison with the prototype as from the liquid phase and from the air by aeration of the liquid phase. Oxygen concentration (activated form) on the surface of the catalyst is significantly higher than the concentration in the liquid phase. The total oxygen content in the liquid phase in the presence of the catalyst is significantly higher than in the absence of catalyst under the same conditions of aeration.
Active centers IU-complex catalyst capable to reversibly oxygenates in aqueous solutions and the activation of coordinated O2in the internal sphere of the metal ion due to the transfer of electron density from the Central metal ion on O2. As a result, the oxygen acquires properties of the superoxide ion O2 -and2-or peroxide ion O2 2-.
The increased reactivity of the coordinated molecular oxygen ions of the metals of the catalyst can be reduced or relieved thermodynamically favorable chetyrehletnego transfer with decreasing full redox reaction of oxygen reduction:
O2+4H++4e-→ 2H2 O,
equal to 1.23 V, or to a significant decrease in activation energy of the free triplet molecules O2turning them after coordination to the singlet state, which facilitates the reaction with singlet molecules of the substrate.
You can also use the catalyst in some processes, for example, catalytic oxidation of sodium sulfide in the white liquor with the purpose of obtaining a polysulfide cooking solution in the pulp and paper industry, but also in the process of pulp bleaching.
Formation on the catalyst surface of activated oxygen to form superoxide ions O2 -and2-or peroxide ion O2 2-causes and antibacterial activity of the catalysts used in the process of water disinfection. The resulting superoxide ions interact with water with the formation of H2O2and ion-radicals composition BUT2 • BUT•. These radical ions have significantly greater rate of diffusion into the cells of microorganisms through the cell membrane and activity in the reactions of interaction with enzymes inside the cells compared with molecular oxygen. After the cessation of water contact with the surface of the catalyst is rapid neutralization of ion-radicals in the result of their recombi the promotion.
The process of catalytic decontamination is carried out by filtering the water through a bed of the catalyst. We found that for effective and sustainable drinking water disinfection enough after catalytic treatment to produce additional chlorination at a flow rate of chlorine of 0.05-0.10 mg/DM3. The technology of disinfection is achieved 10-15 fold reduction of chlorine depending on the source water quality. In addition, it eliminates the presence in treated water free chlorine due to the interaction of the latter with ion-radicals BUT2 • and BUT•with the formation of l. The presence l allows you to increase the exposure time detoxifying agent.
Due to newly acquired specific surface properties of the catalyst also has a high absorption (check) ability in relation to the suspended impurities. Because of this, the catalyst may be used in the processes of purification of waste water according to the method of filtering, while purification by COD due to the oxidation of organic impurities, as a catalyst, and the purification of suspended substances, working at the same time as the adsorbent due to specific properties of the surface; and, moreover, providing disinfection by coli-index with 106-107persons/DM3 up to 103persons/DM3.
The introduction of modifying additives in the composition of the active component provides strong fixation of the active component in the catalyst inventory, which gives its stable activity for a long time, and also increases the ductility of the catalyst mass during forming, and the result is a high quality catalyst granulation composition and density and mechanical strength. Mechanical wear of the carrier on the surface of the granules of the catalyst in the process does not lead to loss of activity since entering the internal layers of the granules of the catalyst. The service life of the proposed catalyst ranges from 3 to 7 years depending on the logging settings catalytic process: temperature, pH, amount of air, etc. if necessary, the catalyst may be made in the form of pellets of any size, Raschig rings and other
The catalyst composition (mass fraction in %):
the active component 40
modifying additive 10
the carrier 50
produced by next technology
The active ingredient, which is a mixture of oxides and/or hydroxides and/or spinels of metals of variable valency (i.e. the catalyst is multifunctional and provides oxidation of organic sulfur and is sotnyk compounds), pre-dried at a temperature of 110° C for 4 hours and produce grinding in a ball mill for 2 hours.
The mixture of active ingredient and carrier - LDPE, forming pellets of the catalyst is carried out at industrial termoplastavtomata for granulating with a minimum load of mixer 60 kg
The mixture of catalyst components is carried out in a high-temperature mixer, the included termoplastavtomata, when the melting point of the polymer carrier. In the mixer load the polymer-carrier - high-pressure polyethylene in the amount of 30.0 kg (50%) and the modifying additive (heteroalicyclic) in an amount of 6.0 kg (10%) and mixed at a temperature 118-122° C for 30-35 minutes Then add the active component in an amount of 24.0 kg (40%). Continue stirring for another 30-60 minutes After mixing the resulting mass is automatically fed to the screw extruder, where with the help of special nozzles is formed in the form of granules. For studies were made of the samples of the catalyst in the form of spherical granules with a size 10-12 mm.
Similarly produce a series of samples of polyfunctional polymeric catalysts, providing the oxidation of organic sulfur and nitrogen compounds (active basis contains oxides and/or hydroxides of metals of variable is th valence). The catalysts of this series contain components (active basis, modifying additive and the media) in various mass ratios of the compositions of the samples are presented in table. 1. Among them there are samples with higher and lower content of the active substrate and modifying additives than is provided by the present invention, No. 1-7, 13, 14, 20, 21, 27, 28, 34, 35, 41-47.
Test the mechanical strength of the granules obtained in example 1, samples of polymer catalysts. The tensile strength of granules for compression is determined according to GOST 473.6-77. The test results for the samples are presented in table. 1. Analysis of the results shows that when the content of the active basis more than 50% (arr. No. 42-47) or modifying additives more than 20% (arr.№6, 13, 20, 27, 34, 41), there is a decrease in the mechanical strength of the granules of the catalyst. That is, the introduction of active bases or modifying additive in an amount greater than that provided by the present invention, results in the decrease of mechanical strength of the granules.
Test activity samples of polymeric catalyst in the process of air oxidation of sulfide, methylmercaptan-, sulfite ions and the amount of organic compounds in solutions in the laboratory is s conditions. The oxidation of the proposed method used the catalysts obtained in examples 1 and 2, with the exception of those that were rejected according to the results of testing the mechanical strength according to example 2.
Experiments conducted on real sulfide wastewater JSC “Angarsk petrochemical company” (JSC “Angarsk”) containing sulfide ions 900-1200 mg/DM3(pH 10.2-11,0), COD 1200-1500 MgO/DM3. Also in experiments using model solutions containing methylmercaptide ions 200-350 mg/DM3(pH 9,5-10,0) and sodium sulfite between 800 and 950 mg/DM3(pH 8.0 to 8.5). Model solutions prepared by adding mercaptan and sodium sulfite in distilled water in the estimated quantities for any given concentration. pH model solutions was adjusted by adding 10%NaOH solution. To obtain a solution containing all three components, real-sulfide waste water containing sulfide ions 900-1200 mg/DM3and COD 200-1500 MgO/DM3introducing additive mercaptan and sodium sulfite in the estimated amounts.
Determination of the concentration of H2S and mercaptans in the original and oxidized waters produce potentiometric method according to GOST 22985-75, the concentration of sulfites - iodometric method and COD titrimetric method LIM f 18.104.22.168-97, described in /4/. The oxidation process on redlagaemoe method is carried out in a laboratory reactor batch. Each sample of the catalyst was loaded into a laboratory reactor layers, between which is established a restrictive grid that provided a good mass transfer.
The volume fraction of the sample of the catalyst in the oxidation reactor is 50% (including free space). The air supply to the reactor from the bottom using a disperser. The oxidation process of sulfur and organic compounds are conducted with the following parameters: temperature - 90° C; pressure of 0.3 MPa, a specific air consumption - 10 m3/m3the oxidation time is 5 minutes
Analysis of the test results of activity of the samples shows that all the samples of polymer catalysts with the content of the active bases of 15-50% and modifying additive of 0.5-20% are active in the oxidation of sulfide ions is not less than 99,5%, methylmercaptide-ions is not less than 99.9%, sulfite ions is not less than 99,5%, COD - not less than 90.0%.
By reducing the number of active component is less than 15% and the modifying additive is less than 0.5% decrease of activity of the samples for all constituents below the specified level - arr. No. 1-5, 7, 14, 21, 28, 35. Table 2 presents the results of testing the activity of samples of the proposed optimal catalyst composition.
Spend tested the Deposit activity of samples of polymer catalysts in the process of absorption and catalytic purification of gases from the SO 2H2S, mercaptans. The oxidation of the proposed method used the catalysts obtained in examples 1 and 2, with the exception of those that were rejected according to the results of testing the mechanical strength according to example 2.
Test the proposed activity of the catalyst for purification of gases from sulfur compounds is performed on real gas mixtures (CHPP-10) in the reactor continuous action in a film mode absorption and catalytic process. The absorbent, which is water, is fed into the reactor from above, the gas countercurrent bottom. The catalyst activity is assessed according to the degree of purification of the gas mixture from the sulfur compounds, to do this, determine the concentration of compounds in the gas mixture at the inlet and outlet of the oxidation reactor.
Determination of the concentration of H2S and mercaptans produce potentiometric method according to GOST 22985-75, SO2-the method described in (4).
Below are the parameters of the process of absorption and catalytic oxidation of sulfur dioxide, sulfides, mercaptans in natural gas using the above initial concentrations.
sulfur oxide is 0.01-4,5
of hydrogen sulfide from 0.01 to 3.0
the pH of the absorbent of 7.1-8.2
Temperature, C 60-80
Pressure, MPa atmospheric
Specific air consumption, l/l 10,5-50
The flow rate of the absorbent, l/l 0,2-1,0
The time of contact of the gas:the catalyst from 0.8 to 1.5
The ratio of the flow rate of the absorbent to the gas flow 0,00015
Gas velocity, m/s 0,14
The oxygen concentration in the gas, % 10
Analysis of the test results of activity of the samples shows that all the samples of polymer catalysts with the content of the active bases of 15-50% and modifying additive of 0.5-2% are active in the oxidation of sulfur dioxide to 99.9%, of hydrogen sulfide is not less than 99.7%with mercaptans is not less than 99.9%. Moreover, the samples of ceramic catalysts have a higher activity, compared with samples of polymer catalysts of the same composition. By reducing the number of active component (less than 15%) and modifying additives (less than 0.5%), a decrease in the activity of the samples for all constituents below the specified level - arr. No. 1-5, 7, 14, 21, 28, 25.
Table 3 presents the results of testing the activity of samples of the proposed optimal catalyst composition.
Test activity prepared in example 1 samples of polymer catalysts in the biocatalytic process wastewater (excluding samples that were rejected in mechanical strength as in example 2).
Test samples of the catalyst on the polymer carrier is carried out at the laboratory who later went biocatalytic reactor, that simulates a two-stage bioreactor, representing two vinyl plastic cylindrical columns, which is filled purified waste water with floating activated sludge in the amount of 1.5 g/DM3and put a wire mesh containers, loading the catalyst on the polymer carrier. In container load samples of the catalysts in an amount corresponding to the ratio of catalyst: water=1:75. The oxidation is carried out in a static mode at a temperature of 18-22° C. the biocatalytic Process waste water is carried out in two stages:
stage 1 - the wastewater is mixed with activated sludge is poured into the first column and oxidized for 4 hours under aeration with a specific consumption of 8.0 m3/m3;
stage 2 - after the first stage of oxidation of the waste water flowing from the first column oxidation in the second and immediately begins the oxidation under anaerobic conditions with mechanical stirring during 4 hours.
For experiments using real wastewater entering the biological treatment plant (BFB) of JSC “Angarsk”, with the concentration of COD 190-215 MgO/DM3nitrogen ammonium 20-30 mg/DM3, nitrite 4-6 mg/DM3, nitrates 25-35 mg/DM3, phenols 18-22 mg/DM3products 8-15 mg/DM3, Detergents 0.7 to 1.2 mg/DM3, grey is odorata 3,0-5,0 mg/DM 3and biocenoses, formed in the process of adaptation of activated sludge to wastewater bare JSC “Angarsk”.
Analysis of the results of the testing activity shows that all samples of polymer catalysts with the content of the active bases of 15-50% and modifying additive of 0.5-20% have high activity in the biocatalytic process cleaning: hydrogen sulfide is 99.9-100%, ammonium nitrogen - 99,5-100%, nitrite - 79-82%, nitrate - 80-82%, COD - 96-98%.
By reducing the number of active component is less than 15% and the modifying additive is less than 0.5% (arr. No. 1-5, 7, 14, 21, 28, 35), there is a decrease in the efficiency of the cleaning process on all counts.
The test results of activity of samples of polymer catalysts in the biocatalytic process of cleaning components: hydrogen sulfide, nitrogen, ammonium, nitrite, nitrate and COD are presented in table 4.
Test the effectiveness of the proposed method to obtain polysulfide cooking solution using the same catalysts prepared according to example 1.
Experiments conducted on real white sulphate liquor used for sulfate pulping at JSC “Baikal pulp and paper mill”, of the following composition:
Total alkalinity 105,0-117,0 g/DM3units Na2O;
NaOH 76,0-78.0 g/DM3unit Na2O;
Active alkalinity 95,0-108,0 g/DM3units Na2O;
Sulfur, thiosulfate 0.8 to 1.3 g/DM3units Na2O;
Sulfur, polysulfide 0.4-0.5 g/DM3units Na2O;
Suspended impurities Not more than 80 g/DM3.
The process of obtaining polysulfide cooking solution by the proposed method is carried out in a laboratory reactor batch. Each sample of catalyst was loaded into a laboratory reactor layers, between which impose restrictive grid. The volume fraction of the sample of the catalyst in the oxidation reactor is 50% (including the free volume of the catalyst). The filing of the original white liquor and air in the reactor is carried out parallel from the bottom of the reactor using a disperser, provide good mass transfer of the gas and liquid phases.
The oxidation of white liquor is conducted with the following parameters: temperature of 80-85° C; specific air consumption 8 m3/m3the time of oxidation (dummy) - 15 minutes
Experiments carried out without pre-treatment of white liquor from suspended impurities. The efficiency of the oxidation process are evaluated according to the following criteria:
the degree of oxidation of sodium sulfide;
the concentration of polysulfides in the oxidized liquor;
the selectivity of the oxidation process.
Content sulfids the th and polysulfide sulfur determined by the methods described in /4/. The results of tests of the effectiveness of the proposed method to obtain polysulfide liquor on samples of polymer catalyst are given in table 5. Analysis of the test results of activity of the samples shows that all samples of polymeric catalyst with a content of active foundations of 15-50% and modifying additive of 0.5-20% provide: the oxidation of sodium sulfide is not less than 73%, the concentration of polysulfide sulfur in oxidized liquor is not less than 6.5 g/DM3and a selectivity of at least 70%. These indicators achieved using white sulphate liquor low sulfinate - 29-31%. Moreover, the samples of ceramic catalysts have a higher activity, compared with samples of polymer catalysts of the same composition. Polysulfide liquor with these indicators is the most suitable for polysulfide pulping.
By reducing the number of active component is less than 15% and the modifying additive is less than 0.5%, there is a decrease in activity of the samples for all constituents below the specified level - arr. No. 1-5, 7, 14, 21, 28, 35.
These examples show that the use of the catalyst in the industry, due to its higher activity and, will increase the efficiency of wastewater treatment and gas emissions, reduce the size of technological devices and the consumption of catalyst, auxiliary products (steam, air, electricity.
The introduction of modifying additives in the media optimizes the process of making a granular catalyst and allows to obtain a catalyst samples in different media: fusible - LDPE and thermally more resistant polypropylene and polystyrene. In the process, which uses the temperature of 40-90° and there is no danger of accidental overheating of the catalyst, appropriate use of catalysts on the EDT. In processes such as the purification of sulfur-alkaline waste water refining process and the oxidation of sodium sulfide in the white liquor with the purpose of obtaining a polysulfide liquor, more appropriate use of catalysts on a more thermally stable media. Here at high initial concentrations of sulfur compounds to achieve sufficient speed the process and reduce the overall dimensions of the column oxidation and consumption of catalyst, the oxidation is carried out at a temperature of 95-120°at a pressure in the column.
In the case of LDPE improving the quality of the finished catalyst in mechanical strength increases the service life of the catalyst by 20-30% compared with about what specimens, made without the use of modifying additives.
Thus, the proposed catalyst on the polymer carrier provides the greatest efficiency gas cleaning and water for a wide range of ingredients that are not available for all known similar catalysts.
1. Heterogeneous catalyst for the oxidation of inorganic and/or organic compounds to the polymer carrier containing the active ingredient to the polymer carrier, wherein the active component, the catalyst contains oxides and/or hydroxides and/or spinel of metals of variable valence and additionally modifying additive, which use organic bases, and/or heteroalicyclic, and/or carbon-containing material in the following catalyst components, wt.%:
The active ingredient 15-50
Modifying additive of 0.5-20
The media and the Rest
2. The heterogeneous catalyst according to claim 1, characterized in that the polymer carrier used as polypropylene, polystyrene or other polymeric media.
FIELD: cleaning waste gases from hydrocarbons; oil refining industry, petrochemical industry and other industries.
SUBSTANCE: proposed method includes oxidation with atmospheric oxygen at elevated temperature in presence of catalyst performed at temperature of 270-280°C in presence of cement-containing catalyst at the following composition of components, mass-%: copper oxide (CuO), 30-50; zinc oxide (ZnO), 19-30; manganese oxide (Mn3O4), 0.5-16; the remainder being technical calcium aluminate.
EFFECT: high degree of cleaning waste gases from hydrocarbons.
FIELD: chemical industry.
SUBSTANCE: the invention is pertaining to the fields of chemical industry, in particular to a method of conversion and an apparatus for conversion of at least one nitric oxide such as NO, NO2 or N2O, which covert an oxide in presence of the catalyst deposited on a metal grid-type structure. The grid-type structure preferably is filamentary and formed by metal or ceramic fibers. It has porosity making more than approximately 85 %. The grid is formed so, that makes channels - mainly crimps, includes generators of turbulence to create a difference of pressure across the grid to stimulate a medium stream running through the pores of the grid, which is not watched at absence of such difference of pressure. The invention offers preferable alternatives of realization of a structured nozzle and monolithic structures, each of which contains a catalyst for conversion of nitric oxide preferably in pores of the grid and-or deposited on the fibers. In one realization the crimped sheets made in the form of grids are placed in series with a ceramic solid monolithic structure. At that the medium containing at least one nitric oxide, which should be converted, is fed in the beginning on the crimped sheets, and then is fed in the monolithic structure for completion of conversion. In other alternative versions of realization the grid-type structure can have the different configurations including a honeycomb structure and may contain metal, metal and ceramics or ceramics, and may be filamentary. The invention ensures a heightened degree of nitric oxides conversion.
EFFECT: the invention ensures a heightened degree of conversion of nitric oxides.
15 cl, 9 ex, 19 dwg, 3 tbl