摘要:
A catalyst for purification of exhaust gases, comprising a monolithic carrier and a catalyst layer formed thereon for reduction of the carbon monoxide, hydrocarbons and nitrogen oxides emitted from internal combustion engines, wherein (1) the catalyst layer contains catalyst particles each comprising a heat-resistant inorganic oxide and at least one noble metal selected from Pt, Pd and Rh, loaded thereon, (2) the catalyst layer contains, as a whole, three noble metals of Pt, Pd and Rh, (3) the catalyst layer contains, at any position ranging from the outer surface to the midpoint of the thickness, catalyst particles comprising a heat-resistant inorganic oxide and 2-10% by weight, based on the inorganic oxide, of Pd loaded thereon, and (4) the catalyst layer has, at the outer surface, exposed catalyst particles comprising an heat-resistant inorganic oxide and at least Rh loaded thereon.
摘要:
A reformer includes two or more catalyst units in the flow path, capable of generating hydrogen from a reactant fluid containing an organic compound or carbon monoxide, by catalysis. In the reformer, at least two of the catalyst units satisfy the following relationship: Heat capacity of the upstream-side catalyst unit≦Heat capacity of the downstream-side catalyst unit. The reformer is improved in the relationship between these catalyst units with respect to heat capacity. This improvement leads to improvement of the reformer in safety, heating characteristics during the start-up period, efficiency of hydrogen production and reduction in production of CO as the coproduct.
摘要:
A catalyst-adsorbent for purification of exhaust gases, including a monolithic carrier and a catalyst-adsorbent layer formed thereon, the catalyst-adsorbent layer including a catalyst for reduction of the carbon monoxide, hydrocarbons and nitrogen oxides emitted from internal combustion engines and an adsorbent for reduction of the hydrocarbons emitted during cold start of the engines. The catalyst is composed mainly of catalyst particles each including a heat-resistant inorganic oxide and at least one noble metal selected from Pt, Pd and Rh, loaded thereon, the catalyst containing at least catalyst particles each comprising a heat-resistant inorganic oxide and 2-30% by weight, based on the oxide, of Pd loaded thereon, the adsorbent comprising adsorbent particles composed mainly of zeolite.
摘要:
A catalyst for exhaust gas purification has at least one monolith carrier, at least one first catalyst layer having a three-way catalytic activity, provided on the carrier, and a second catalyst layer having a hydrocarbon purification activity, provided on the first catalyst layer. In a gasoline engine automobile provided with the above catalyst for exhaust gas purification in the exhaust gas system, the hydrocarbons present in the exhaust gas can be converted at a high efficiency by introducing secondary air into the exhaust gas in front of the catalyst to make the exhaust gas lean, at the engine start when a large amount of unburnt hydrocarbons are present in the exhaust gas. Further, the engine warm-up property of the automobile can be improved by the heat generated by the catalytic reaction of the hydrocarbons. The catalyst further exhibits a three-way catalytic activity even during the steady state engine operation after warm-up.
摘要:
A catalyst composition for purification of exhaust gas, including (a) high-silica zeolite having a Si/Al ratio of 40 or more, subjected to ion exchange with at least one metal selected from Pt, Pd, Rh, Ir and Ru, and (b) a heat-resistant oxide containing at least one metal selected from Pt, Pd, Rh, Ir and Ru; a catalyst for purification of exhaust gas, including a monolith carrier and the catalyst composition supported on the carrier; and a process for producing the catalyst. The catalyst has high activity for exhaust gas purification even when the catalyst contains Rh--, --, which is an expensive catalyst component, in a very small amount.
摘要:
A reformer is disposed in the flow path of a reactant fluid. The reformer includes an electrically heatable heater unit of honeycomb structure, in the upstream of the flow path of a reactant fluid, and a catalyst unit of honeycomb structure capable of generating hydrogen from a reactant fluid containing an organic compound or carbon monoxide, by catalysis, in the downstream of the above heater unit. The heater unit and catalyst unit satisfy the following relationship: Cell density of the heater unit≦Cell density of the catalyst unit. The reformer improve efficiency for production of hydrogen and reduce CO as the by-product.
摘要:
A catalyst for exhaust gas purification, comprising a heat-resistant inorganic monolith carrier and a catalyst layer loaded thereon, the catalyst layer including a catalyst composition containing at least one noble metal selected from Pt, Pd and Rh, as an active catalyst component, and active alumina. The catalyst composition has a specific surface area of at least 50 m.sup.2 /g and a porosity of at least 50%. This catalyst for exhaust gas purification contains noble metal(s) in a well dispersed state, has excellent high-temperature durability, and is low in thermal deterioration of catalyst performance. Hence, the catalyst can be suitably used as a converter installed in engine manifolds of gasoline engine automobiles, or as a heater having improved purification ability for the exhaust gases emitted from automobiles during their cold start.
摘要:
An exhaust gas purification system includes an adsorbent containing an adsorbent element for adsorbing harmful compounds such as hydrocarbon in an exhaust gas and a catalyst containing a catalyst element for lowering the harmful compounds in the exhaust gas, each disposed in the exhaust gas pipe of an internal combustion engine. When an oxidizing gas is added to the exhaust gas or amounts of combustion gas and fuel are regulated, for a given period, in the process in which the hydrocarbon in the exhaust gas produced at the cold start-up of the internal combustion engine are adsorbed by the adsorbent and desorbed from the adsorbent as a temperature of the adsorbent is increased by the exhaust gas, an exhaust gas composition containing excessive oxygen is provided and the desorbed hydrocarbon are oxidized on the catalyst. With this arrangement, the harmful compounds in the exhaust gas, in particular, the hydrocarbon produced in a large amount at the cold start-up of the engine can be effectively purified.
摘要:
An exhaust gas purification system includes an adsorbent containing an adsorbent element for adsorbing harmful compounds such as hydrocarbon in an exhaust gas and a catalyst containing a catalyst element for lowering the harmful compounds in the exhaust gas, each disposed in the exhaust gas pipe of an internal combustion engine. When an oxidizing gas is added to the exhaust gas or amounts of combustion gas and fuel are regulated, for a given period, in the process in which the hydrocarbon in the exhaust gas produced at the cold start-up of the internal combustion engine are adsorbed by the adsorbent and desorbed from the adsorbent as a temperature of the adsorbent is increased by the exhaust gas, an exhaust gas composition containing excessive oxygen is provided and the desorbed hydrocarbon are oxidized on the catalyst. With this arrangement, the harmful compounds in the exhaust gas, in particular, the hydrocarbon produced in a large amount at the cold start-up of the engine can be effectively purified.
摘要:
In the plasma reaction vessel (1) of the invention, two or more laminate-structures (6) having ceramic formed bodies (3, 4) in which a plasma generating electrode (2) capable of generating plasma is formed in two-tape-form, and an electrically continuous film-like electrically conductive electrode (5) held between the two ceramic formed bodies (3, 4) are formed in such a manner as to form a plasma generating space (7) containing mutual laminate planes therein. Of the electrically conductive electrodes (5), adjacent ones are capable of having electric discharge produced therebetween so as to generate the plasma in the plasma generating space (7) and of generating uniform stabilized plasma at low electric power, it being possible to reduce a passage resistance to a gas passing therein.