Showing papers on "Selective catalytic reduction published in 1984"
TL;DR: In this paper, the hydrogenation of carbon monoxide over iron surfaces has been investigated at medium pressure (7 atm) and over the temperature range 473-578 K. This deactivation appears to be associated with the deposition of a graphitic type of surface carbon.
93 citations
TL;DR: In this paper, the catalytic reduction of O2 to H2O2 at a glassy carbon electrode in the presence of adsorbed films of polymeric anthraquinone has been investigated in buffered aqueous solutions saturated with air or oxygen, by rotating disk voltammetry.
68 citations
TL;DR: In this paper, a combined micro-reactor surface analysis system was used to combine pre-reaction and post reaction surface analysis to be coupled with medium pressure (5-10 atm) catalytic reaction studies.
29 citations
Patent•
14 Dec 1984
TL;DR: In this article, the removal of nitrogen oxides from exhaust gases by catalytic reduction is described. But the method is not suitable for the case of sulfur oxides, since it requires high temperatures above 300°C and low temperatures below 300° C.
Abstract: Process for the removal of nitrogen oxides from exhaust gases, in particular from exhaust gases containing sulfur oxides, by catalytic reduction. As a reduction agent a gas mixture obtained by catalytic conversion of methanol either by catalytic dissociation or by steam reforming is mixed with the exhaust gases and passed over a catalyst, wherein the nitrogen oxides are reduced to nitrogen. According to the first variant, one operates with conventional catalysts above 300° C., according to the second variant, with new catalysts below 300° C.
29 citations
TL;DR: In this article, the selectivity in the catalytic reduction of nitroarylalkylnitriles with hydrazine and metal catalysts was studied, and the results showed that it is not optimal.
26 citations
TL;DR: In this article, the catalytic reduction of nitrogen monoxide with hydrogen or ammonia was investigated, and the activity orders of the catalysts were as follows, depending on the reductant: Cu2+>Ag+>Ni2++>Cs+\simeq Co2+ Â Co2 + Â H+ H+ (hydrogen), Cu2>Co2+ >Ag+ >Ni 2+>C+ C+ C + H+ C 2 Â C+ H2 Â N 2 + H2 + C 2 +
Abstract: 12-Molybdophosphoric acid and its metal salts, supported on SiO2 (H3PA and MPA/SiO2), were found to exhibit significant activities for the catalytic reduction of nitrogen monoxide with hydrogen or ammonia, the latter reductant being more reactive The activity orders of the catalysts were as follows, depending on the reductant: Cu2+>Ag+>Ni2+>Cs+\simeq Co2+\simeq H+ (hydrogen), Cu2+>Co2+>H+>Ag+>Ni2+>Cs+ (ammonia) It is of value to mention also that H3PA/SiO2 exhibited ten times many activity when ammonia was applied The extent of the cation exchange (X) of CuXH3−2XPA/SiO2 influenced the catalytic activity differently, depending again on the reductant, although the maximum activity was obtained with both reductants when X was 11 Nitrogen monoxide was decomposed by a stoichiometric reaction with the reduced site on Cu11H08PA/SiO2, especially when the catalyst was reduced with hydrogen, although no oxygen was detected in the product, the initial rate being comparable to that of the reduction with hydrog
12 citations
Patent•
28 Feb 1984
TL;DR: In this article, a process for purification of flue gas is described, in which flue gases are desulphurised by scrubbing with a lime-containing suspension and then the nitrogen oxides are catalytically selectively reduced by mixing with ammonia, and an apparatus for carrying out this process is described.
Abstract: The invention relates to a process for the purification of flue gas in which the flue gas is desulphurised by scrubbing with a lime-containing suspension and then the nitrogen oxides are catalytically selectively reduced by mixing with ammonia, and an apparatus for carrying out this process. According to the invention, the desulphurised flue gas, prior to the catalytic reduction of the nitrogen oxides, is heated by regenerative heat exchange with the clean gas and by supply of additional heat to the NOx reduction temperature of 220 to 270 DEG C.
11 citations
Patent•
27 Mar 1984TL;DR: In this article, a selective catalytic reduction (SCR) was proposed for reducing the oxides of nitrogen (NO x ) content of a furnace flue gas. But the SCR process is not suitable for high temperature environments.
Abstract: A selective catalytic reduction process (SCR) for reducing the oxides of nitrogen (NO x ) content of a furnace flue gas. The process comprises splitting the flue gas into two streams, treating one of the streams with an SCR process with the same amount of NH 3 as NO x , and then recombining the streams. By treating only a portion of the flue gas using an NH 3 /NO x ratio of unity, the amount of catalyst required is reduced while the residual NO x and NH 3 contents of the recombined streams is controlled to desired levels.
9 citations
Patent•
15 Dec 1984
TL;DR: In this paper, it was shown that one or more rare metals from the group comprising ruthenium, rhodium, palladium and/or platinum have been applied in or on this interlayer.
Abstract: A catalyst, especially for eliminating nitrogen oxides from exhaust gases containing sulphur oxides by catalytic reduction of the nitrogen oxides to nitrogen, contains one or more rare metals on a support and is characterised in that the support contains an inert base support to which an interlayer of gamma -Al2O3, a silica or an aluminium silicate, if desired together with an oxide of lanthanum and/or of one of the lanthanides has been applied, and that one or more rare metals from the group comprising ruthenium, rhodium, palladium and/or platinum have been applied in or on this interlayer.
9 citations
Patent•
29 Feb 1984
TL;DR: In this article, the authors describe a process for the catalytic purification of nitrogen oxide-containing exhaust gases from diesel engines, in which ammonia is added to the exhaust gases and the gas mixture is passed over a non-noble metal catalyst which is, if appropriate, applied to a support.
Abstract: The application relates to a process for the catalytic purification of nitrogen oxide-containing exhaust gases from diesel engines, in which ammonia is added to the exhaust gases and the gas mixture is passed over a non-noble metal catalyst which is, if appropriate, applied to a support.
8 citations
Patent•
27 Dec 1984
TL;DR: In this article, the authors proposed to increase a adsorbing amt. against NH 3 and to facilitate a recovery of activity by adding ≤70wt% titanium compd. such as TiO 2, etc.
Abstract: PURPOSE: To increase a adsorbing amt. against NH 3 and to facilitate a recovery of activity by adding ≤70wt% titanium compd. such as TiO 2 , etc. expressed in terms of the weight of TiO 2 to a denitrating catalyst for catalytic reduction of ammonia contg. regenerated titanium. CONSTITUTION: A spent catalyst is separated into the catalyst component and the non-catalyst component and the catalyst component is pulverized. One or more kinds of titanium compds. such as titanium oxide, titanic acid, orthotitanic acid, etc. are added to this catalyst powder in the rate of, by weight %, 0W70 preferably 10W50, expressed in terms of TiO 2 , and then they are mixed by a dry method or by a wet method. This mixture is molded, dried and calcined by a usual process to regenerate the denitrating catalyst. Any regenerated catalyst contg. at least titanium as the catalyst component will suffice for the denitrating catalyst for catalytic reduction of ammonia. COPYRIGHT: (C)1986,JPO&Japio
Patent•
01 May 1984
TL;DR: In this paper, an oxide, hydroxide or carbonate of Ca and/or Ba is added to a waste denitration catalyst with catalytic reduction of ammonia contg. SOX in the range up to 150mol% of the sulfate group in said waste catalyst, whereby the above-mentioned sulfate groups are stabilized, the outflow of SO3 in the stage of reusing the waste catalyst is decreased and the generation of clogging, corrosion, etc. of the device is prevented.
Abstract: PURPOSE:To enable the reuse of a waste denitration catalyst by adding an adequate amt. of oxide of C or B or the like to the waste denitration catalyst having increased sulfate group after it is used in treating waste gas contg. SOX thereby stabilizing the sulfuric acid and decreasing the outflow of SO3. CONSTITUTION:An oxide, hydroxide or carbonate of Ca and/or Ba is added to a waste denitration catalyst with catalytic reduction of ammonia contg. increased sulfate group after it is used for a denitratrion treatment of waste gas contg. SOX in the range up to 150mol% of the sulfate group in said waste catalyst, whereby the above-mentioned sulfate group is stabilized, the outflow of SO3 in the stage of reusing the waste catalyst is decreased and the generation of clogging, corrosion, etc. of the device is prevented. The denitration performance of the catalyst is considerably improved by the addition of the above-mentioned compd.
TL;DR: In this article, the title diketone was converted via the dixetal 5 into a monoketal 6 which was then reduced to afford a mixture of two epimeric ketal-alcohols 7 and 8.
Patent•
03 Aug 1984
TL;DR: In this paper, a new process for the manufacture of N-nitrosoazabicycloalkanes by catalytic reduction of 1,2-cycloalkanedicarboximides to the corresponding amines which are then nitrosated in situ.
Abstract: New process for the manufacture of N-nitrosoazabicycloalkanes by catalytic reduction of 1,2-cycloalkanedicarboximides to the corresponding amines which are then nitrosated in situ. The process is particularly advantageous when the reduction is carried out in the presence of a catalyst such as poisoned copper chromite under hydrogen pressures of between 60 and 120 bars and at temperatures situated between 200 and 800 DEG C.
Patent•
10 Oct 1984
TL;DR: In this article, the authors describe a process for purifying Claus tail gas by catalytic reduction of the said gas with formation of hydrogen sulphide, cooling of the gas, condensing and separating water from the exhaust gas, adjusting the H2S/SO2 ratio necessary for the further Claus reaction by combining the tail gas with an SO2-containing gas produced by combustion and conducting the combined gases through a first Claus catalyst stage below the sulphur dew point.
Abstract: PROCESS FOR PURIFYING CLAUS TAIL GAS The invention relates to a process for purifying Claus tail gas by catalytic reduction of the said gas with formation of hydrogen sulphide, cooling of the gas, condensing and separating water from the exhaust gas, adjusting the H2S/SO2 ratio necessary for the further Claus reaction by combining the tail gas with an SO2-containing gas produced by combustion and conducting the combined gases through a first Claus catalyst stage below the sulphur dew point. The process is characterised in that the SO2-containing gas produced by combustion is cooled to a regeneration temperature or cooling temperature and conducted through the second catalyst stage charged with sulphur or respectively freed from sulphur and thereby regenerates or cools the said stage, the sulphur taken up in the regeneration phase is condensed out and separated from the SO2-containing gas, after being combined with the tail gas, is conducted through the first catalyst stage for the formation and separation of sulphur. The process permits a flexible control of the temperature of the regenerating gas, corresponding to the regeneration and cooling phases.
TL;DR: In this paper, the catalysts were investigated for the catalytic reduction of nitrogen monoxide with hydrogen or ammonia, the latter reductant being more reactive than the former, and the maximum activity was obtained with both reductants when X was 1.1.1H 0.8PA/SiO2.
Abstract: 12-Molybdophosphoric acid and its metal salts, supported on SiO2 (H3PA and MPA/SiO2), were found to exhibit significant activities for the catalytic reduction of nitrogen monoxide with hydrogen or ammonia, the latter reductant being more reactive. The activity orders of the catalysts were as follows, depending on the reductant: Cu2+>Ag+>Ni2+>Cs+\simeq Co2+\simeq H+ (hydrogen), Cu2+>Co2+>H+>Ag+>Ni2+>Cs+ (ammonia). It is of value to mention also that H3PA/SiO2 exhibited ten times many activity when ammonia was applied. The extent of the cation exchange (X) of CuXH3−2XPA/SiO2 influenced the catalytic activity differently, depending again on the reductant, although the maximum activity was obtained with both reductants when X was 1.1. Nitrogen monoxide was decomposed by a stoichiometric reaction with the reduced site on Cu1.1H0.8PA/SiO2, especially when the catalyst was reduced with hydrogen, although no oxygen was detected in the product, the initial rate being comparable to that of the reduction with hydrog...