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 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 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-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 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:
A catalyst body comprising a carrier and a catalyst layer containing an alkali metal and/or an alkaline earth metal, loaded on the carrier, which catalyst further contains a substance capable of reacting with the alkali metal and/or the alkaline earth metal, dominating over the reaction between the main components of the carrier and the alkali metal and/or the alkaline earth metal. With this catalyst body, the deterioration of the carrier by the alkali metal and/or the alkaline earth metal is prevented; therefore, the catalyst body can be used over a long period of time.
摘要:
A honeycomb structure 1 having numerous through channels passing through along the X axis and being partitioned with porous partition walls 2 which is characterized in that: a total pore volume (D) cc/g in end portions of the partition walls 2 is smaller than the total pore volume in other portions of partition walls 2; and relationships between the total pore volume (D) cc/g in end portions and the partition wall thickness (B) μm and cell pitch (C) mm in other portions of partition walls are defined as; the total pore volume (D)≦the partition wall thickness (B)×0.004, and the total pore volume (D)≦(1/the cell pitch (C))×0.18; and a method of producing a honeycomb structure. There is provided with the honeycomb structures 1 having various cell structures and being reinforced at their end portions, with exhibiting satisfactory and practical erosion resistance.
摘要:
There is provided a catalyst carrier comprising ceramic substrate composed mainly of ceramics, and a pre-coat layer applied on the ceramic substrate, wherein the pre-coat layer comprises titanium oxide (TiO2) in an amount of at least 30 mass %. Also there is provided a catalyst body comprising such a catalyst carrier, and alkali metal and/or alkaline earth metal loaded on the catalyst carrier. There are provided a catalyst carrier showing less deterioration by alkaline metal and/or alkaline earth metal to be loaded on the carrier, and a catalyst body showing less deterioration by alkaline metal and/or alkaline earth metal being loaded on the carrier.