摘要:
The invention provides a noble metal-containing supported catalyst which contains one of the noble metals from the group Au, Ag, Pt, Pd, Rh, Ru, Ir, Os or alloys of one or more of these noble metals in the form of noble metal particles on a powdered support material. The particles deposited on the support material have a degree of crystallinity, determined by X-ray diffraction, of more than 2 and an average particle size between 2 and 10 nm. The high crystallinity and the small particle size of the noble metal particles lead to high catalytic activity for the catalyst. It is particularly suitable for use in fuel cells and for the treatment of exhaust gases from internal combustion engines.
摘要:
The invention provides a combined heat and power plant with an integrated gas production system. The combined heat and power plant contains a steam reformer heated with a gas burner which converts a mixture of hydrocarbons and water vapour into a reformate gas stream containing hydrogen and carbon monoxide. The plant further contains a reactor system with several stages for removing carbon monoxide from the reformate gas stream. The plant also contains a heat exchanger for removing heat energy from the reformate gas stream and a fuel cell unit for producing electrical energy by catalytic reaction of the hydrogen contained in the reformate gas with oxygen in the fuel cell, wherein the reformate gas stream is supplied to the anode in the fuel cell unit and the anode waste gas is taken to the gas burner of the steam reformer as fuel, via a gas pipe. The reactor system for removing carbon monoxide from the reformate gas stream contains, according to one embodiment of the invention, a low temperature shift reactor and a downstream methanisation reactor and the heat exchanger for cooling the reformate gas stream leaving the steam reformer to the inlet temperature of the low temperature shift reactor is located in the reformate gas stream between the steam reformer and the low temperature shift reactor. This combined heat and power plant is operated according to the invention in such a way that the reformate gas contains 5 to 10 vol. % of unreformed hydrocarbon which enables the flame in the gas burner to be monitored using an ionisation detector when burning the anode waste gas in the gas burner of the steam reformer.
摘要:
A process is provided for operating a three-way catalyst that contains an oxygen storage component, that has a minimum and a maximum filling degree for oxygen and that is located in the exhaust gas line of an internal combustion engine. The air/fuel mixture supplied to the engine is varied in such a way that the filling degree of the oxygen storage component in the catalyst is held within a set-point interval between the minimum and maximum filling degree. According to this process, in order to regulate the air/fuel mixture, migration of the filling degree out of the set-point interval is checked in a test phase in such a way that the filling degree is increased or lowered relative to the instantaneous value (initial value) by short-term enrichment or reduction in richness of the air/fuel mixture supplied to the engine by a certain amount and immediately returned to the initial value by a short-term opposing change in the air/fuel mixture (lean/rich pulse sequence or rich/lean pulse sequence). In the case of a breakthrough of lean or rich exhaust gas through the catalyst during the test phase, the air/fuel mixture is enriched or reduced in richness in order to correct the filling degree, wherein the amount by which the filling degree during the test phase is increased or decreased is such that no breakthrough of lean or rich exhaust gas takes place through the catalyst when the filling degree of the oxygen storage component is within the set-point interval.
摘要:
The present invention provides devices for glass melt devlivery and methods for using these devices. In these devices, a delivery nozzle comprising at least one platinum group metal material is directly heated by electricty. To facilitate heating, a cylindrical heating ring is mounted in ceramic base. The device's construction ensures a regulatable heating of the nozzle and the melted glass flux.
摘要:
The present invention provides an exhaust gas treatment unit for an internal combustion engine. A first catalyst unit produces ammonia from corresponding constituents in a rich exhaust gas composition. A second catalyst unit that is located downstream of the first catalyst unit temporarily stores the ammonia produced by the first catalyst unit in the presence of a rich exhaust gas composition. In the presence of a lean exhaust gas composition, the nitrogen oxides present in the exhaust gas are subjected to a reduction reaction using the temporarily stored ammonia as reducing agent. The exhaust gas treatment unit also contains a third catalyst unit that is located between the other two catalyst units, and oxidizes the nitrogen oxides present in the exhaust gas at lean exhaust gas conditions to a such an extent that 25 to 75 vol. % of the nitrogen oxides entering the second catalyst unit consist of nitrogen dioxide.
摘要:
The invention relates to a process for catalytic autothermal steam reforming of alcohols having two or more carbon atoms by directing a preheated educt or reactant mixture of the alcohols, oxygen and water or steam over a catalyst. The process is conducted in an adiabatic manner wherein the catalyst comprises at least one platinum group metal on an oxidic support selected from the group consisting of aluminum oxide, silicon dioxide, titanium dioxide or mixed oxides thereof and zeolites, and that the educt or reactant mixture contains additional hydrocarbons, which are reformed at the same time as the alcohols.
摘要:
The invention comprises a process for making a membrane electrode assembly comprising a polymer electrolyte membrane having two opposite faces, on each face of which is applied a catalyst layer and a gas distribution layer. The two gas distribution layers in the membrane electrode assembly are formed by hydrophobized carbon substrates which, using appropriate inks containing at least one catalyst, dissolved ionomer and solvent, are each coated with a catalyst layer and are then laid on opposite faces of the polymer electrolyte membrane with the catalyst layers still in the moist state. Afterwards, a firm bond between electrolyte membrane, catalyst layers and carbon substrates is produced by treating the membrane electrode assembly at elevated temperature under pressure.
摘要:
The present invention relates to three-dimensional catalyst gauzes for gas reactions knitted in two or more layers from noble metal wires in which the meshes of the individual layers are joined to one another by pile threads. In these catalyst gauzes weft threads are inserted between the mesh layers. These catalyst gauzes have an increased catalytic activity and efficiency in gas reaction. These improvements enable operation with a lower total amount of noble metal employed, for example by reducing the number of gauzes and/or the length of the wire processed in the catalyst gauze and/or the wire thickness, without thereby having to accept disadvantages with respect to the yield and selectivity of the gas reaction, mechanical strength and service life of the gauzes or unavoidable loss of noble metal.
摘要:
An oxygen storage material comprising cerium oxide and at least one second oxide of a metal M1 is disclosed as well as a process for manufacturing the material and the use of this material in an exhaust gas cleaning catalyst. In a preferred embodiment the oxygen storage material comprises particles from a Ce/M1 mixed oxide solid solution coated with an oxide of another metal M2. Metal M1 e.g. can be calcium or zirconium while metal M2 most preferably is aluminum.
摘要:
The present invention relates to a method for the production of a membrane electrode assembly comprising a polymer electrolyte membrane with two opposing membrane surfaces and a cathode and an anode electrode each comprising a catalyst layer and a gas distribution layer. Each catalyst layer is interposed between a membrane surface and the corresponding gas distribution layer. The catalyst layer of the cathode and/or the catalyst layer of the anode comprise at least two sub-layers. According to the present invention at least one of the sub-layers of the cathode electrode and/or the anode electrode is applied directly to the surface of the membrane while the remaining sub-layers are applied to the corresponding gas distribution layers. Finally the assembly of the coated membrane and the coated gas distribution layers is produced.