Method of cleaning exhaust gases from carbon monoxide and hydrocarbons and the method of preparation of the catalyst for its implementation

 

(57) Abstract:

Usage: cleaning of exhaust gases of internal combustion engines, as well as in the chemical, gas and petrochemical industry from CO and organic compounds, for example, cyclohexane. The inventive exhaust gases at 160 - 1100oWith contact with a catalyst containing wt.%: PdO 0,06 - 0,12; NiO 1,30 - 3,80; Cr2O31,50 - 4,30; Al2O3the rest of it. The catalyst was prepared by impregnation of the support with an aqueous solution of nitrates of Pd, Ni and Cr. The mass ratio (Pd(NO3)2: Ni (NO3)2: 6 H2O: Cr (NO3)39H2O well 1: (46 - 136) : (35,8 - 312). The media is Al2O3is, or modification, pre-calcined at 500 - 700oC. Nitrate Cr get when you add in the impregnating solution of HNO3and Cr2O3. 2 C and 1 C. p. F.-ly, 2 tab..

The invention relates to processes for cleaning exhaust gases from the impurities of oxides of carbon, hydrocarbons, organic compounds using catalysts and can be used for the decontamination of exhaust gases of internal combustion engines, as well as in the chemical, gas and petrochemical industries.

Izvestia, in fine condition, and chromium trioxide add the calculated amount of fine aluminum oxide. After stirring to this mixture is added a portion Zola aluminum hydroxide, containing 10% alumina. The resulting mass after mixing is formed into tablets, dried at 100aboutC and calcined at 500aboutC. the Obtained sample is then impregnated with an aqueous solution of palladium nitrate, and then re-dried at 100aboutC and calcined at 500aboutWith on the air. The catalyst contains as the active component of Ni and Cr in the form of oxides in a molar ratio of NiO:Cr2O31 0,5-0,6 and their content of 5-30% and palladium at the content of 0.01-0.2% of the Catalyst was tested in the cleaning process gases formed during hot drying enamels. Combustible gas components are xylene, benzene, butanol, and the naphtha fraction. In the ignition WITH the catalyst is not used [1]

The main disadvantage of this method is that it is sequential, and so labor - intensive to obtain catalysts. Separate introduction of components (NiO + Cr2O3and Pd is not conducive to the manifestation of the effect of spillover oxygen, as is the case when one is So this catalyst has a high activity and stability.

The closest solution to the problem is a known method of purification of exhaust gases of vehicles from CO and hydrocarbons on the catalyst containing PD or other platinum group metal and the oxides of Ni, Cr and Al [2]

Closest to the proposed method of preparation of the catalyst is known a process comprising impregnation of the carrier of Al2O3the catalytically active substances, followed by drying and calcining. The catalyst contains Pd, NiO, and one or more oxides of Ba, Mo, V, Zr and other elements [3] the Disadvantage of this method is not sufficiently high catalyst activity.

The aim of the invention is to develop a technology method of purification of industrial gas emissions of CO, hydrocarbons and organic compounds and method of producing the catalyst for its implementation, with high activity and stability in a wide temperature range.

This is solved by a method of cleaning exhaust gases from the impurities of carbon monoxide and hydrocarbons, organic compounds, including their contact with the oxide nickelchromium catalyst at elevated campanii, wt. Nickel oxide 1,30-3,80 the chromium Oxide of 1.50-4.30 palladium Oxide 0,06-0,12 alumina Rest, and the contacting is carried out at a temperature of 160 1100aboutC.

The task is also solved by a method of producing a catalyst for purification of exhaust gases from the impurities of carbon monoxide and organic compounds comprising the mixture of nitrate and chromium compounds with subsequent drying and calcination, in which the application of a mixture of Nickel nitrate and chromium compounds by impregnation of a pre-calcined to 500-700aboutWith a carrier of alumina -, -, -form a solution containing Nickel nitrate, chromium compound and a palladium nitrate, taken in a mass ratio of Ni(NO3)26H2O chromium compound Pd(NO3)2equal(46-136) (35,8-312) 1, and then re-calcining at 650 1100aboutC. as a carrier of aluminum oxide used exhaust oxide adsorbent purification process of benzene. Furthermore, as compounds of chromium use nitrate or chromic anhydride.

The invention consists in the discovery of new properties of palladium oxide with further introduction of the oxide nickelchromium system its sposoben new and unexplored. Typical catalysts characterized by the decrease in activity with increasing temperature processing, or, at best, its stabilization in a narrow temperature interval. The method of preparation of the catalyst consists of applying the active components of the oxides of Nickel, chromium and palladium by single impregnation finish medium aluminum oxide with various modifications (-, -, -) acidified with nitric acid aqueous solution of nitrates of Ni, Cr and Pd or an aqueous solution of nitrates of Ni, Pd and chromic anhydride and hold thermo-activation of the samples obtained by heat treatment in air in the temperature range of 650-1100aboutC.

Experimentally proved, that the introduction of free nitric acid in the impregnating solution containing the nitrates of Ni, Cr and Pd or nitrates of Ni, Pd and chromic anhydride, increases the effect of thermo-activation.

Obtaining the catalyst is carried out as follows. Granular alumina -, -, - modifications, pre-calcined in the temperature range 500-700aboutWith, impregnated with a solution containing nitrates of Nickel, chromium and palladium or nitrates of Nickel, palladium and chromium anhydride, dried at 140-200aboutC and calcined in the temperature range of 650-1100aboutaboutC.

The technical result of the proposed invention is expressed in a significant increase in catalytic activity and thermal stability of the catalyst for purification of gas emissions of carbon monoxide, a significant simplification of the production technology due to the exclusion of a number of stages, the possibility of its use for the purification of organic compounds. The activity of the catalyst in the oxidation of CO is determined by the temperature of its complete transformation into a CO2in a laboratory setup flow type under atmospheric pressure air mixture containing 1,0%, flow rate 10000 h-1with chromatographic registration components of the gas mixture. The catalyst believe the more active, the lower the temperature the full afterburners.

Study of the oxidation mixture (CO + C6H12) on the catalyst, obtained by the proposed method, perform the following way. Through the reaction tube with the catalyst at different temperatures miss gas mixture (CO + C6H12+ O2+ N2). Cyclohexane contribute to the reaction tube by ozonation mixture is Aut chromatographic after mixing with the main gas stream at the inlet of the reactor, the residual amount of output from it.

P R I m e R s 1-12 relate to the method of preparation of the catalyst. Example 13 relates to a method of preparation of the catalyst of the prototype. Example 14 relates to a method for cleaning exhaust gases. The invention is illustrated by the following examples.

P R I m e R 1. The purpose of the preparation of the catalyst composition, wt. NiO 1,3; Cr2O31,5; Pd 0,06; Al2O3else, 10.0 g of the carrier-shape, calcined at 500aboutWith, placed in a porcelain Cup, which is poured at once under stirring with an aqueous solution (19.3 ml) containing 0.52 g of Ni(NO3)26H2O 0,81 g SG(NO3)39H2O and to 0.011 g of Pd(NO3)2. Palladium in the initial mixture is introduced into the aqueous solution (2.6 ml). The ratio of the components in the solution 46,0:71,7:1. Concentrations of Nickel, chromium and palladium in the initial solution equal 5,4; 5,4; 0,270 g/L. the Contents of the Cup is at room temperature and periodic stirring for 1.5-2.0 hours, then dried at 140-200aboutWith and calcined portions, respectively, at 400, 500, 600, 650, 700, 800, 900, 1000 and 1150aboutC.

P R I m m e R 2. To obtain a catalyst containing, by weight. NiO 1,30; Cr2O31,50; PdO 0,12; Al2O3else, 3.0 g novtel the solution, containing 0,158 grams Ni(NO3)26H2O 0,062 g of chromic anhydride and 0.007 g of Pd(NO3)2. The ratio of these salts in solution, respectively, is 22.4: 35,8:1. Concentrations of Nickel, chromium and palladium in the original solution are 16,9, 16.0 and 1.63 g/l, the Catalyst is dried and calcined portions at 500, 650 and 900aboutC.

P R I m e R 3. To obtain a catalyst containing, by weight. NiO 2,50; Cr2O32,90; PdO 0,06; Al2O3else, 10.0 g of the carrier-shape, calcined at 700aboutWith, placed in a porcelain Cup, then poured in one go while stirring to 19.3 ml of impregnating solution containing 1.04 g of Ni(NO3)26H2O, 1.63 g Cr(NO3)39H2O and to 0.011 g of Pd(NO3)2. The ratio of these salts in solution, respectively, is 92,0:144, 0mm:1. Concentrations of Nickel, chromium and palladium in the original solution amount to 10.9, 10.9 and 0,270 g/L. Further surgery to obtain a catalyst and their operation is similar to that described in example 1.

P R I m e R 4. The catalyst composition, wt. NiO 3,80; Cr2O34,30; PdO 0,06, Al2O3the rest are impregnated with 30 g of carrier-shape, calcined at 700aboutWith that solution (58 ml) containing of 4.75 g of Ni(NO3)26H2O, of 7.36 g of Cr(NO

P R I m e R 5. Order to obtain a catalyst containing, by weight. NiO 3,80; Cr2O34,30; PdO 0,12; Al2O3else, 10.0 g of aluminum oxide forms, calcined at 600aboutWith, fill in 19.3 ml of an aqueous solution containing 1,58 g Ni(NO3)26H2O, of 2.45 grams Cr(NO3)39H2O and is 0.023 g of Pd(NO3)2. The ratio (mass) of the components in the solution, respectively is: 68,7 106,5 1. Further surgery to obtain a catalyst and their operation is similar to that described in example 1.

P R I m e R 6. Differs from example 5 that to obtain the impregnating solution containing the nitrates of Ni, Cr and Pd use of 7.5% nitric acid. Media - Al2O3.

P R I m e R 7. Differs from example 6 that for a sample use 15% nitric acid. Media-Al2O3.

P R I m e R 8. Differs from example 5 that to obtain the impregnating solution containing the nitrates of Ni, Cr and Pd, using a 30% nitric acid. Media-Al2O3.

P R I m e is El (-Al2O3) prepare a solution (3.0 ml) containing 0,474 g nitrate Ni, 0,007 g Pd(NO3)2and 0.14 g of chromic anhydride. Concentrations of Nickel, chromium and palladium respectively equal to 31.9; 24,4; 1.06 g/l Drying were carried out as described in example 1. Separate portions of the sample annealed at 500, 650 and 900aboutC.

P R I m e R 10. Differs from example 9 that use media-modification (alumina carrier used for the preparation of the catalyst APK-2). Temperature calcinations at 500, 650 and 900aboutC.

P R I m e R 11. To obtain a catalyst composition, wt. NiO 3,80, Cr2O3(without palladium oxide) 4,30, -Al2O325,0 g impregnate of 20.0 ml of a solution containing of 3.95 g of Ni(NO3)26H2O and 6.14 g of Cr(NO3)39H2O. the concentration of ions of Nickel and chromium respectively 39,8 and 39.8 g/l After drying as described in example 1, the sample portions calcined at temperatures of 400, 700 and 1000aboutC.

P R I m e R 12. To obtain a catalyst containing, by weight. NiO 3,80; Cr2O34,30, PdO 0,12; Al2O3else, 1.0 g of aluminum oxide, representing a departure Al2O3manufactured by Rhone-Poulenc after use as adsorbent and subsequent UB>6H2O, 2,45 g SG(NO3)39H2O and is 0.023 g of Pd(NO3)2. The ratio (mass) of the components in the solution, respectively, is 68,7:106,5:1. After drying, the catalyst is calcined at temperatures of 500, 700, 800 and 900aboutC.

P R I m e p 13 (prototype). To 100 g of waste in the process of hydrogenation of benzene industrial nickelchromium catalyst composition, wt. Ni 22,3; NiO 26,1; Cr2O326,8; NiS 1,7; moisture 18, the rest undetectable substances, add 80 ml of nitric acid solution containing 8 g of 100% NGO3and the mass is maintained at room temperature for 45 minutes and Then the excess solution is separated from the solid phase by filtration and use it with the addition of an appropriate quantity of concentrated nitric acid for treatment of subsequent portions of the spent catalyst. The solid is dried at 80-120aboutC and calcined at 600aboutWith 3 hours Receive oxide nickelchromium catalyst composition, wt. NiO 56,2, Cr2O332,4, the rest of undetectable matter.

P R I m e R s 14. The original flue gas composition, vol. CO 1.0 and the air 99,0 speed 10000 h-1contact with the layer of the catalyst composition, wt. NiO 3,80; Cr2O34,30; PdO 0,12 at a temperature of 160about

Analysis of the data given in table. 1 shows that the proposed invention is a method of cleaning gas emissions by contacting them with oxide nickelchromium catalyst provides full clearance from SB at temperatures much lower than the known catalysts. So, on new catalysts full cleaning WITH can be achieved at temperatures 156-196aboutWith, while on a known catalyst at 265-270about(Example 13). With regard to applied nickelchromium catalyst (without palladium oxide) (example 11) the interval of his work, provided 100% clean is 320-360aboutC.

From the data table. 1 shows that the new catalysts are extremely resistant to high temperatures: maximum activity they are after heat treatment in the range of 800-1000aboutC.

From table. 1 also shows that the introduction of nitric acid in the impregnating solution favorably affect the activity of the catalyst after high temperature proquali the positive effect on the activity it has not. It follows that the decisive role in the processes leading to significant growth in activity and thermostability, an oxide of palladium. In this respect, perhaps, positive influence and phase transformations in the specified catalytic system.

The results presented in table. 2, show that the proposed active catalyst oxidizes cyclohexane with carbon monoxide, i.e., is the catalyst for purification of waste gases from hydrocarbons.

When implementing the present invention provides the following advantages:

high degree of purification of exhaust gases from the impurities of carbon monoxide and hydrocarbons;

high activity and thermal stability of the catalyst;

the simplicity and reliability of the method of producing a catalyst;

the utilization of waste upon receipt of the catalyst.

1. Method of cleaning exhaust gases from carbon monoxide and hydrocarbons, including their contact with the catalyst containing palladium and oxides of Nickel, chromium and aluminum at an elevated temperature, characterized in that the used catalyst after heat treatment at 650 - 1100oWith containing palladium in the form of its oxide, when sled - 1,50 - 4,30

Alumina - Rest

and the contacting is carried out at 160 - 1100oC.

2. A method of producing a catalyst for purification of exhaust gases from carbon monoxide and hydrocarbons, including the application on alumina, palladium, Nickel oxide and the oxide of the second transition metal impregnation of the carrier with an aqueous solution of compounds of palladium, Nickel and the second transition metal, followed by drying and calcining, characterized in that the use of alumina -, or modification, pre-calcined at 500 - 700oWith, palladium is applied in the form of oxide, impregnating the solution as compounds of palladium, Nickel and the second transition metal is used, respectively nitrates when the mass ratio of Pd(NO3)2: Ni(NO3)26H2O : Cr(NO3)39H2O= 1 : (46 - 136) : (35,8 - 312), and after calcination are heat-treated in air at 650 - 1100oC.

3.The method according to p. 2, characterized in that the chromium nitrate in the impregnating solution used in the form of a solution of chromium trioxide in nitric acid.

 

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