Abstract:
The invention relates to a method and a device for cleaning flowing gases. To reduce the total emissions, nitrogen oxides, especially NO and NOx, are extracted at least partially from the gas to be scrubbed, in the temperature range from 50 and 300° C., preferably between 50 and 150° C. To extract the nitrogen oxides, an intermediate storage medium is used that is composed of a storage material and a supporting material for the storage material. The intermediate storage medium having in particular a composition of the formal chemical formula Ag.CuAl2O4 in an Al2O3 matrix, with the composition being a spinel or being of the spinel type, and with the composition having characteristic spinel lines in the x-ray spectrum, where 0≦x
Abstract translation:本发明涉及清洗流动气体的方法和装置。 为了减少总排放量,氮氧化物,尤其是NO和NO x至少部分地从待洗涤的气体中提取,温度范围为50-300℃,优选为50-150℃。为了提取氮 氧化物,使用由储存材料和用于储存材料的支撑材料组成的中间储存介质。 中间储存介质特别是在Al 2 O 3基质中具有形式化学式Ag.CuAl 2 O 4的组成,其组成为尖晶石或尖晶石型,并且组合物在x射线谱中具有特征尖晶石线, 其中0 <= X <1。
Abstract:
A catalyst and a process for producing the catalyst are provided. For the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons, the catalyst contains a spinel containing the metals copper, zinc and aluminum.
Abstract:
A process is described for preparing esters of an acid component selected from among polybasic C4-C10 carboxylic acids and an alcohol component selected from among C3-C12 alkanols or from among C3-C12 alkanediols, the alkyl chain of which may have interruption by from 1 to 3 oxygen atoms, by a) heating at boiling point, in a reaction zone and in the presence of an esterification catalyst, a mixture essentially consisting of the acid component or of an anhydride thereof and of the alcohol component, b) using rectification to separate the vapor comprising alcohol and water into an alcohol-rich fraction and a water-rich fraction, and c) returning the alcohol-rich fraction into the reaction zone and conducting the water-rich fraction out of the process. The process is simple to carry out and permits rapid achievement of essentially quantitative conversion.
Abstract:
NO.sub.x, where x is 1 and 2, in exhaust gases is reduced over heterogeneous catalysts with hydrocarbons, carbon monoxide, hydrogen or mixtures thereof in the presence of oxygen from 100 to 650.degree. C. and an absolute pressure of from 0.5 to 50 bar by a process in which the heterogeneous catalysts used are bimodal or polymodal compounds of the general formula IA.sub.1-x M.sub.2 O.sub.4 (I),which, if required, are doped with rare earth metals, noble metal, titanium, vanadium, molybdenum, tungsten or mixtures thereof, and whereA is magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin or mixtures thereof,M is aluminum, gallium, indium, tin, chromium, manganese, iron, cobalt, nickel, copper, zinc or mixtures thereof andx is from 0 to 0.99,whose oxygen atoms are in a cubic close packed arrangement and A is present in the tetrahedral sites and M in the octahedral sites, it also being possible for A to occupy octahedral sites if an equivalent amount of M occupies tetrahedral sites.
Abstract:
A process for selective catalytic reduction of nitrogen oxides from exhaust gases, preferably those from diesel engines in vehicles, using pulsed superstoichiometric addition of NH.sub.3 or NH.sub.3 -releasing substances, comprises controlling the pulsed superstoichiometric addition of NH.sub.3 in such a way that, after it has started, the addition is interrupted again only when the amount of NH.sub.3 stored in the catalyst has reached a specific upper threshold value which is predetermined in accordance with the catalyst properties and the catalyst volume, the amount of NH.sub.3 stored being calculated from the difference between the metered amount of NH.sub.3 and the amount of NO.sub.x separated off, which is determined from the NO.sub.x concentration in the exhaust gas and the average degree of separation, and the addition of NH.sub.3 is resumed only when the amount of NH.sub.3 stored in the catalyst, which is determined in the same way, has reached a predetermined lower threshold value, this pulsed addition of NH.sub.3 being interrupted after a predetermined number of cycles until the amount of NH.sub.3 stored in the catalyst, which is determined in the manner described, has completely reacted, this completing one entire cycle of the pulsed addition of NH.sub.3.
Abstract:
The present invention relates to a method for operating a purification device, to a purification device and to the use of same. To reduce the emission of pollutants, a filter body through which a fluid can flow and comprising a catalyst, is exposed to a stream of gas which is to be purified. Before the gas enters the catalyst, a reducing agent is added in the flow direction of the gas, and after a certain treatment point, during which the gas, which is to be purified, is flowing in the catalyst, reducing agent is added once more to the flowing gas by a feeding mechanism and contact with the catalyst is maintained.
Abstract:
The mixture described is a mixture of isomeric nonanol diesters of a dicarboxylic acid, selected from the class consisting of a mixture of diesters of adipic acid in the 1H NMR spectrum of which, observed in CDCl3, the ratio of the area under the resonance signals at chemical shifts in the range from 1.0 to 2.0 ppm with respect to TMS to the area under the resonance signals at chemical shifts in the range from 0.5 to 1.0 ppm with respect to TMS is from 1.20 to 5.00 and a mixture of diesters of phthalic acid, in the 1H NMR spectrum of which, observed in CDCl3, the ratio of the area under the resonance signals at chemical shifts in the range from 1.1 to 3.0 ppm with respect to TMS to the area under the resonance signals at chemical shifts in the range from 0.5 to 1.1 ppm with respect to TMS is from 1.00 to 4.00. The diesters of adipic and phthalic acid are suitable as plasticizers for PVC-based molding compositions and have high compatibility, a low cold crack temperature, low torsional rigidity and/or high thermal stability.
Abstract translation:所述的混合物是二羧酸的异构壬醇二酯的混合物,其选自在1 H NMR光谱中己二酸二酯的混合物,其在CDCl 3中观察到的共振信号下的面积比例 相对于TMS,1.0〜2.0ppm范围内的化学位移相对于TMS,化学位移为0.5〜1.0ppm的共振信号下的面积为1.20〜5.00,邻苯二甲酸二酯, 在1H NMR谱中,在CDCl3中观察到,在化学位移下的共振信号下的面积相对于TMS的1.1至3.0ppm范围内的化学位移下的共振信号下的面积的比例在 己二酸和邻苯二甲酸的二酯适用于PVC基成型组合物的增塑剂,具有高相容性,低冷裂纹温度,低扭转度 刚性和/或高热稳定性。
Abstract:
A storage catalyst includes (1) a component that has a catalytic reducing action for nitrogen oxides at least in the presence of hydrocarbons, and (2) a component that stores NOx at least at temperatures of below 100° C. The catalytically active component is of the general chemical formula AaBbO4, where A is one or more divalent metals and B is one or more trivalent metals, and where a+b≦3 and a, b>0. The reaction enthalpy or the chemical activity between the catalytically active component and the NOx-storing component is low at least up to temperatures of 600° C.
Abstract translation:存储催化剂包括(1)至少在烃存在下对氮氧化物具有催化还原作用的组分,和(2)至少在低于100℃的温度下存储NOx的组分。催化活性组分是 的一般化学式AaBbO4,其中A是一种或多种二价金属,B是一种或多种三价金属,并且其中a + b <= 3和a,b> 0。 催化活性组分和NOx储存组分之间的反应焓或化学活性至少高达600℃的温度。
Abstract:
The present invention is directed to a purification device that includes a porous body and a catalyst. To reduce the emission of pollutants, a pollutant-containing stream of gas flows through the porous body.
Abstract:
A catalyst and a process for producing the catalyst are provided. For the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons, the catalyst contains a spinel containing the metals copper, zinc and aluminum.