摘要:
Catalysts for the decomposition of N2O into nitrogen and oxygen in the gas phase, which comprises a porous support composed of polycrystalline or vitreous inorganic material, a cerium oxide functional layer applied thereto and a layer of oxidic cobalt-containing material applied thereto are described.The catalysts can be used, in particular, as secondary or tertiary catalysts in nitric acid plants.
摘要:
Catalysts for the decomposition of N2O into nitrogen and oxygen in the gas phase, which comprises a porous support composed of polycrystalline or vitreous inorganic material, a cerium oxide functional layer applied thereto and a layer of oxidic cobalt-containing material applied thereto are described.The catalysts can be used, in particular, as secondary or tertiary catalysts in nitric acid plants.
摘要:
A device and a method are described for lowering the content of NOx and N2O in gases. The device comprises: A) a container (1) and, arranged therein, B) two reaction steps connected one after the other for removing NOx (DeNOx stage) by reducing NOx with a nitrogen-containing reducing agent and, downstream thereof, for removing N2O by catalytic decomposition of N2O to N2 and O2 (DeN2O stage), which each consist of one or more catalyst beds (7, 8) and through which the gas that is to be purified flows, wherein C) the at least one catalyst bed of the DeNOx stage (7) contains a catalyst for reducing NOx with nitrogen-containing reducing agents which catalyst contains zeolites doped with transition metals, including the lanthanides, D) the at least one catalyst bed of the DeN2O-stage (8) contains a catalyst for decomposing N2O into N2 and O2, which contains one or more catalytically active compounds of elements selected from groups 5 to 11 of the Periodic Table of the Elements with the exception of iron-doped zeolites, and E), upstream of the DeNOx stage (7), a device for introducing a nitrogen-containing reducing agent into the stream of the NOx and N2O-containing gas is provided. The combination used according to the invention of catalysts permits a very simple structure and a very economic operation of the reactor.
摘要:
A method of reducing the content of NOx and N2O in gases using a gaseous reducing agent which is used in the amount required for reduction of the NOx in the presence of one or more iron-laden zeolites which have no pores or channels having a width of greater than or equal to 7 Ångström in the crystal structure and at temperatures of less than 450° C. in the reaction zone is described. In this method, the flow rate of the gas mixture and/or the amount of catalyst is/are selected so that the desired degree of decomposition of N2O is achieved. The method can be used, in particular, in nitric acid production, in power stations and in gas turbines.
摘要:
A process for removing N2O and NOx from offgases by catalytic decomposition of N2O by means of iron-containing zeolite catalysts and catalytic reduction of the NOx by means of reducing agents, the deNOx stage connected downstream of the deN2O stage being operated at inlet temperatures of T
摘要:
Improved reactors for catalytic, exothermic gas phase reactions with, as seen in the flow direction of a feed gas, which contains at least one oxidant and at least one component to be oxidized, an entry zone (1), a reaction zone (2) comprising at least one catalyst (4) and an exit zone (3) for the product gas are described. The reactors, at least in the area of the entry zone (1), have means, for example insulating jackets (6) and/or devices for the transport of cooling agents, which decrease the transport of heat produced in the reaction zone (2) into the entry zone (1) and thus decrease the risks of pre-ignition of the feed gas mixture employed or of the course of undesired side reactions in the entry zone (1) and/or wherein the inner walls of the reactor, at least in the area of the entry zone (1), are elaborated from inert material.The feed gas enters into the entry zone (1) as a homogeneous gas mixture with respect to its substance composition via one or more feed lines (30).The reactors can especially be employed for ammonia oxidation, for example in nitric acid plants, in which transition metal catalysts preferably elaborated in honeycomb form with smaller cross sections than the customarily employed platinum gauzes are used.
摘要:
The disclosure involves a method for reducing the content of NOx and N2O in gases. The method includes the conduction of a gas containing N2O and NOX over a series of two catalyst beds containing of one or more zeolites charged with iron followed by the: addition of a reduction agent for NOX between the catalyst beds. The first catalyst bed reaction zone is used to degrade the N2O and the catalyst bed second reaction zone reduces the NOX and breaks down at least part of the remaining N2O. The inventive device comprises at least one radially traversed catalyst bed.
摘要:
The method comprises passing an N2O- and NOx-containing gas over a sequence of two catalyst beds, adding reducing agents for NOx and for N2O between the catalyst beds in such an amount that not only NOx but also a predetermined proportion of N2O is reduced. The reaction conditions are set so that the N2O content of the gas is reduced by not more than 95%, based on the N2O content at the entrance of the first catalyst bed, by decomposition to nitrogen and oxygen in the first catalyst bed and that not only chemical reduction of NOx but also chemical reduction of N2O occurs in the second catalyst bed so that the N2O content of the gas is reduced by at least 50%, based on the N2O content at the entrance of the second catalyst bed.
摘要翻译:该方法包括在两个催化剂床的序列上通过含N 2 O和NO x-x N的气体,向其中加入还原剂, 并且催化剂床之间的N 2 O 2的量不仅仅是NO 2 x N 2,而且N 2 O 2的预定比例减少 。 设定反应条件使得气体的N 2 O 2 O含量基于在入口处的N 2 O 2含量降低不超过95% 第一催化剂床,通过在第一催化剂床中分解成氮气和氧气,并且不仅在第二催化剂床中发生NO 2 X的化学还原,而且还发生N 2 O 2的化学还原 催化剂床,使得气体的N 2 O 2 O含量基于第二催化剂床入口处的N 2 O 2含量降低至少50%。
摘要:
Improved reactors for catalytic, exothermic gas-phase reactions having, viewed in the flow direction of a feed gas, an inlet zone (1), a reaction zone (2) containing at least one catalyst (4), and an outlet zone (3) for the product gas, are described. The reactors are provided in the inlet zone (1) or in the inlet zone (1) and the reaction zone (2) with an insulating liner (6) and/or apparatuses for the transport of cooling media and/or the interior walls of the reactor in the inlet zone (1) or in the inlet zone (1) and the reaction zone (2) consist of inert material. The insulating liner and/or cooling media reduce heat transport from the reaction zone (2) into the inlet zone (1) and thus reduce the risk of preignition of the feed gas mixture used or occurrence of undesirable secondary reactions in the inlet zone (1).
摘要:
A process for removing N2O and NOx from offgases by catalytic decomposition of N2O by means of iron-containing zeolite catalysts and catalytic reduction of the NOx by means of reducing agents, the deNOx stage connected downstream of the deN2O stage being operated at inlet temperatures of T
摘要翻译:一种通过使用含铁沸石催化剂催化分解N2O并通过还原剂催化还原NOx的方法从废气中除去N2O和NOx,脱硝阶段连接在脱硝阶段的下游,在入口温度为T 并且具有选择的N 2 O / NO x比例的deN2O阶段的入口气体,并且选择脱硝阶段的温度,压力和空间速度的操作参数,以得到N 2 O 降解80〜98%。 在这些条件下,在脱硝阶段的出口处建立了30-70%的NOx氧化程度,其定义为NO 2的摩尔量与NOx的总摩尔量的比率。 其结果是下游脱硝阶段可以在最佳条件下运行。 还提供了一种用于执行该过程的装置。