The catalyst for purification of gas emissions of oxides of nitrogen
(57) Abstract:The invention relates to the protection of the environment from toxic industrial emissions, or rather to the catalysts for purification of exhaust gases of internal combustion engines from nitrogen oxides. Describes the catalyst for purification of gas emissions of oxides of nitrogen containing media on the basis of silicon dioxide in the form of highly dispersed synthetic material are presented with an average particle size (5-20)10-12mm, and the ratio of the applied components, calculated on the dry matter is: Nickel oxide of 5.3% and 6.6%, chromium oxide 7-10%. This catalyst has significant advantages and a higher activity and duration of work without loss of activity compared with the known. table 1. The present invention relates to the means of protecting the environment from toxic industrial emissions, namely the catalysts for purification of exhaust gases of internal combustion engines from oxides of nitrogen.Known catalyst for reduction of nitrogen oxides, representing faience media, which caused the oxides of Nickel and chromium in the following ratio of components, wt.%:
The oxide of the PR operates at a temperature of 400oC, flow rate of the gas stream 100.000 h-1and the degree of gas purification from nitrogen oxides in these conditions is 98%, the duration of operation of the catalyst is not more than 100 hours.Closest to the proposed technical solution is the catalyst for purification of gas emissions from nitrogen oxides, including oxides of silicon, chromium and Nickel containing additional oxides of barium, iron in the following ratio, wt.%:
The chromium oxide - 16,0-18,0
Nickel oxide is 0.5 - 5,1
The barium oxide - 0,05 - 0,15
Iron oxide - 0,03-0,25
The silicon oxide - Rest
(EN 2068732 C1, 10.11.96).This catalyst contains oxides of barium and iron in addition to the above-mentioned ratio of the components and uses as a carrier silica.The catalyst is characterized by increased activity, especially when applied as a reducing agent aqueous solution of urea.However complicated the process of obtaining media by precipitation of sodium metasilicate sulfuric acid requires additional costs for the removal of water, the sodium salt of sulfuric acid.The necessary control over the content of sodium and sulfur as toxic catalysate is it Nickel (15-30%) and chromium (60-76%), as the concentration of precipitated oxides of chromium and Nickel on a carrier of silica gel remains low, which leads to increase of consumption of the catalytic mass.The authors propose the catalyst for purification of gas emissions of oxides of nitrogen containing media on the basis of silicon dioxide, which is fine synthetic material-aerosol with an average particle size (5 to 20)10-12mm, and the ratio of the applied components, calculated on the dry matter is: Nickel oxide of 5.3% and 6.6%, the chromium oxide - 7 - 10%.Distinctive features of the invention are used as media superfine synthetic material-aerosol with an average particle size (5 to 20)10-12mm and the ratio of the applied components in terms of dry substance, which is: Nickel oxide of 5.3% and 6.6%, chromium oxide 7-10%.The catalyst operates in the presence of the reducing agent is an aqueous solution of ammonia at a temperature of 310-350oC and flow rate 15103h-1with less salt content of Nickel and chromium in the impregnated composition.Aerosil - fine synthetic silica grades a-300. The average particle size of Aerosil (5-20)1tx2">Example 1. Prepare media of Aerosil and polyvinyl acetate dispersion (in the ratio 1:10). The resulting mass is formed into granules of spherical shape with a diameter of 4 mm, dried at a temperature of 205oC for 24 hours and calcined at a temperature of 900oC for 30 minutes. The resulting carrier is treated with water vapor for 1 hour to saturate and impregnate alternately salt solutions: 10% Nickel nitrate Ni (NO3)2; 25% chromium nitrate Cr(NO3)3. The catalyst was dried for 24 hours at a temperature of 205oC and calcined at a temperature of 550oC for 2.5 hours.The resulting catalyst has a composition in wt. %:
NiO 6,1; Cr2O37,8; silicon dioxide else.Through the catalyst miss the combustion products of diesel fuel. As a reducing agent is applied ammonia dissolved in water. Testing is carried out at atmospheric pressure, the temperature 310-350oC, the volumetric gas flow rate 15-16103h-1.The degree of purification of exhaust gases of the internal combustion engine nitrous oxide is 90%.Example 2. Of Aerosil and polyvinyl acetate dispersions prepared media in the recipe of pre turn: 5% of Nickel nitrate Ni(NO3)2and 5% of chromium nitrate Cr(NO3)3. The catalyst was dried for 24 hours at a temperature of 205oC and calcined at a temperature of 550oC for 2.5 hours.The resulting catalyst has a composition in wt.%: PIO 1,6; Cr2O34,6; the rest of silicon dioxide.The degree of recovery of nitrogen oxide in the exhaust gas of the internal combustion engine is 80% at the temperature of the gas mixture 310oC, the volumetric gas flow rate 15-16103h-1, atmospheric pressure. As a reducing agent is applied ammonia dissolved in water.Example 3. Prepare media of Aerosil and polyvinyl acetate dispersions for the formulation of example 1. Impregnation of the carrier is carried out with aqueous solutions of salts in the following sequence: chromium nitrate 5% Cr(NO3)3; nitrate Nickel - 5% Ni(NO3)2moreover , the impregnation with solutions of salts is carried out after saturation of the media with water vapor. The carrier coated with the catalyst mass is dried for 24 hours at a temperature of 205oC and calcined at a temperature of 550oC.The resulting catalyst has a composition in mass profits: NiO 2,8%; Cr2O34.6%, the rest of silicon dioxide.
oC, the volumetric gas flow rate 15-16103h-1, atmospheric pressure.Example 4. The carrier obtained in formulation example 1, was impregnated with solutions of salts, mixed in a 1:1 ratio by volume: of Nickel nitrate 10% Ni(NO3)2; nitrate chromium 25% Cr(NO3)3. A carrier coated with a catalyst mass is dried for 24 hours at a temperature of 205oC and calcined at a temperature of 550oC for 2.5 hours.The resulting catalyst has a composition in wt.%: PIO 6,6; Cr2O310; the rest of silicon dioxide. Through the catalyst miss the combustion products of diesel fuel as a reductant use ammonia water. At a temperature of 310oC, flow rate of the gas stream 15103h-1and atmospheric pressure, the degree of reduction of nitrogen oxides is 90%.As follows from the table that the catalysts produced in accordance with the invention:
- do not contain expensive materials and their compounds, as the main material of the carrier is an aerosol, sustainest to get more active components - oxides of Nickel and chromium on the media at a lower salt content of Nickel and chromium in the catalyst mass in comparison with the known;
- in the manufacture does not require complex chemical engineering processes (coprecipitation, filtering, multi-stage washing and equipment;
- provide a degree of purification of exhaust gases from nitrogen oxides in the range of 80-90% at least 120 hours at a temperature of 310-350oC without loss of activity.Therefore, the catalyst has significant advantages and a higher activity compared with the known.Sources of information
1. Author's certificate N 1447393, M CL 01 J 23/26, the Catalyst for purification of gases from nitrogen oxides, published. Bull. N 48, 30.12.88,2. Patent N 2068732 "the Catalyst for purification of gas emissions from nitrogen oxides) class. B 01 J 23/86, published. 10.11.1996, bull. N 31. The catalyst for purification of gas emissions of oxides of nitrogen containing media on the basis of silicon dioxide, characterized in that as the carrier used superfine synthetic material are presented with an average particle size (520)10-12mm, and the ratio of the applied components in terms of dry ve the
FIELD: the invention may be used for protection of environment.
SUBSTANCE: On the first step the exhaust gases are set in contact with a recirculated liquid melt of urea holding predecessors of melamine and NH3, on the second step - with a raw liquid melt of melamine. The gas washer has two stages located one above the other. The upper section of the low stage has a sprayer, and the low section- a gas distributor. The upper section of the upper stage has a sprayer and one or more plates with chaffers located opposite it.
EFFECT: improves purification of gases exhausting from a reactor from melamine and other admixtures, increases energy effectiveness of the process of the melamine synthesis process due to better usage of the heat of exhaust gases.
15 cl, 4 dwg
SUBSTANCE: invention relates to absorbents for cleaning gases. Disclosed is use of guaiacol as an agent for cleaning gases from nitrogen oxides. When nitrogen oxides react with guaiacol, nitrogen oxides are deposited in a very small volume in form of a solid product.
EFFECT: invention enables fast and efficient removal of nitrogen oxides from a gaseous medium.
SUBSTANCE: invention relates to a method of washing away ammonia nitrogen and/or ammonium nitrogen and/or urea nitrogen from spent gases rich in these nitrogen compounds, in ammonia or urea production apparatus. The method involves treating nitrogen compounds in a gas washer with hypochlorite-containing solutions to form an intermediate product which, under acidic or neutral reaction conditions, is converted to elementary nitrogen and a salt. Conversion of the nitrogen compounds to elementary and a salt takes place at pH ranging from 4 to 6.
EFFECT: method provides efficient washing of ammonia, urea and ammonia compounds from spent gas.
11 cl, 2 dwg, 1 ex
FIELD: process engineering.
SUBSTANCE: this invention relates to cleaning of flue gas containing solid particles entrapped by said gas. This invention relates to cleaning of flue gas containing solid particles entrapped by said gas including: heating gas bearing solid particles for their sublimation if they are not sublimated; bringing said gas in direct contact with appropriate solid reagent selected from slaked lime, quick line or commercially available limestone to remove sublimated ammonium chloride therefrom and to remove cleaned gas from the system.
EFFECT: efficient cleaning.
7 cl, 4 dwg
FIELD: production of hydrorefining catalyst.
SUBSTANCE: the invention presents a method of production of hydrorefining catalysts, that provides for preparation of non-calcined catalyst for hydrorefining of hydrocarbonaceous raw materials polluted with low-purity heteroatoms. The method includes: combining of a porous carrying agent with one or several catalytically active metals chosen from group VI and group III of the Periodic table of elements by impregnation, joint molding or joint sedimentation with formation of a predecessor of the catalyst containing volatile compounds, decrease of the share of the volatile compounds in the predecessor of the catalyst during one or several stages, where at least one stage of decrease of the shares of the volatile compounds is carried out in presence of at least one compound containing sulfur; where before the indicated at least one integrated stage of decrease of the share of volatile compounds - sulfurization the indicated predecessor of the catalyst is not brought up to the temperatures of calcination and the share of the volatile compounds in it makes more than 0.5 %. Also is offered a not-calcined catalyst and a method of catalytic hydrorefining. The invention ensures production of a catalyst of excellent activity and stability at hydrorefining using lower temperatures, less number of stages and without calcination.
EFFECT: the invention ensures production of a catalyst of excellent activity and stability at hydrorefining using lower temperatures, less number of stages and without calcination.
10 cl, 8 ex, 4 dwg
FIELD: petroleum processing catalysts.
SUBSTANCE: invention related to hydrofining of hydrocarbon mixtures with boiling range 35 to 250оС and containing no sulfur impurities provides catalytic composition containing β-zeolite, group VIII metal, group VI metal, and possibly one or more oxides as carrier. Catalyst is prepared either by impregnation of β-zeolite, simultaneously or consecutively, with groups VIII and VI metal salt solutions, or by mixing, or by using sol-gel technology.
EFFECT: increased isomerization activity of catalytic system at high degree of hydrocarbon conversion performed in a single stage.
40 cl, 2 tbl, 19 ex
FIELD: petrochemical process catalysts.
SUBSTANCE: invention provides catalyst for hydrofining of petroleum fractions, which catalyst shows elevated strength and stability upon regeneration. This is achieved supplementing alumina-based carrier with texturing additives selected from alumina and gibbsite thermochemical activation product in amount 5 to 30 wt %. Alumina additive is used with particle size not larger than 15 μm and gibbsite thermochemical activation product with that not larger than 45 μm. As binding agent in catalyst, nitric acid is used at molar ratio to alumina (0.01-0.03):1 and/or aluminum nitrate/ aluminum metal reaction product in amounts 1 to 5% based on alumina. Prior to be impregnated, catalyst is steamed at elevated temperature and impregnation is carried out from aqueous solution of nickel-cobalt-molybdenum-containing complex at pH 1-3.
EFFECT: improved performance characteristics of catalyst.
2 cl, 3 tbl, 10 ex
FIELD: petroleum processing catalysts.
SUBSTANCE: invention relates to catalysts for deep processing of hydrocarbon stock and can be employed in petroleum processing and petrochemical industries. Particularly, invention provides catalyst for diesel fraction hydrodesulfurization process, which contains, as active component, oxygen-containing molybdenum and cobalt and/or nickel complex compound at Mo/(Co+Ni) atomic ratio 1.5-2.5 and is characterized by specific surface 100-190 m2/g, pore volume 0.3-0.5 cm3/g, prevailing pore radius 80-120 Å. Catalyst support is constituted by alumina or alumina supplemented with silica or montmorillonite. Described are also catalyst preparation procedure and diesel fraction hydrodesulfurization process.
EFFECT: increased catalytic activity and resistance of catalyst against deactivation in presence of diesel fuel hydrocarbon components and sulfur compound of thiophene and its derivatives series.
8 cl, 1 tbl, 7 ex
FIELD: isomerization and disproportionation catalysts.
SUBSTANCE: invention relates to crystalline α-chromium oxide, chromium-containing catalytic compositions, method for preparation thereof, and to a process of fluorine distribution in hydrocarbon and/or halogenated hydrocarbon in presence of indicated catalytic compositions. In claimed α-chromium oxide, about 0.05 to about 2 atomic % chromium in the lattice of α-chromium oxide is substituted by nickel atoms and, optionally, further chromium atoms in the lattice are substituted by trivalent cobalt atoms, the total amount of nickel and trivalent cobalt atoms in the α-chromium oxide lattice not exceeding 6 atomic %. Claimed α-chromium oxide is prepared via coprecipitation of solid substance by introducing ammonium hydroxide, this method being supplemented by introducing an excess of ammonium nitrate into precipitated mixture before dehydration step and calcination step at 375 to 1000°C in presence of oxygen. Chromium-containing catalytic compositions containing crystalline nickel-substituted α-chromium oxide as chromium-containing component optionally treated with fluorination agent are also claimed. Composition preparation procedure comprises: (a) coprecipitation of solid substance by introducing ammonium hydroxide into aqueous solution of soluble bivalent nickel salt, soluble trivalent chromium salt, and optionally soluble bi- or trivalent cobalt salt, wherein solution contains at least three moles nitrate per mole chromium and has concentration of nickel from about 0.05 to about 2 mol % based on total content of nickel, chromium, and cobalt (if present) in solution and total concentration of nickel and cobalt (if present) not higher than 6 mol % on the same basis; (b) collecting coprecipitated solid substance obtained in step (a); (c) drying collected solid substance; and (d) calcination of dried solid substance at 375 to 1000°C in presence of oxygen.
EFFECT: increased activity of catalytic composition in above-indicated processes.
15 cl, 8 dwg, 13 ex
FIELD: petroleum processing.
SUBSTANCE: invention relates to preparation of protective-layer catalysts for hydrofining of petroleum fractions in petroleum processing industry. Invention provides catalyst containing oxides of molybdenum, nickel and/or cobalt, silicon, and aluminum, which catalyst is molded in the form of hollow cylindrical granules. Starting composition for preparation of alumina-based carrier includes structuring additive, 5.0-8.5%, kaolin, 2.0-5.0%, and alumino-nickel-molybdenum and/or alumino-cobalt-molybdenum catalyst, 10-20%. Thus prepared alumina-supported contains 0.5-4.0% nickel oxide and/or cobalt oxide and 0.8-3.0% silicon oxide.
EFFECT: increased degree of hydrogenation of unsaturated hydrocarbons, prevented coking of basic catalyst, and reduced pressure gradient.
3 cl, 4 ex
SUBSTANCE: principle refers to catalyst and method of complex purification of waste gases of different production, heat and power utilities, automobile transport, which works on natural gas (methane). Described is a method of complex purification of effluent gases from nitrogen oxides, carbon oxide and hydrocarbons and it involves passing the effluent gases at temperatures 455-600°C through a layer of mechanical mixture of nickel chromium oxide industrial catalyst a copper zink nickel industrial catalyst in a volume composition of 1:1 to 20:1 respectively. To the effluent gases, methane up to a volume composition of CH4/O2 0.07-0.15 can be added before passing it through the catalyst layer. Nickel chromium oxide industrial catalyst contains NiO 38-42 %; ZnO 28-32 %; NiO 4-6 % and not less than Al2O3 17 % masses.
EFFECT: increasing of the purifying index of effluent gases.
3 cl, 4 ex