Abstract:
This invention is a HfO2-containing catalyst support material for use in high temperature catalytic processes, such as catalytic combustion, wherein the HfO2 is present in a sufficient amount to impart thermal stability on the catalyst support at temperatures in excess of 1,000 DEG C, as well as, heterogeneous, supported-platinum group metal catalyst employing the HfO2-containing support material and monolithic catalyst structures in which the HfO2-containing support material is used as a substrate washcoat for the active catalyst material. Also described are high temperature catalytic processes, such as catalytic combustion, employing catalysts and catalyst structures which utilize the HfO2-containing support material.
Abstract:
The invention is an improved catalyst structure and its use in highly exothermic processes like catalyst combustion. This improved catalyst structure employed integral heat exchange in an array of longitudinally disposed, adjacent reaction passage-ways or channels, which are either catalyst-coated (14) or catalyst-free (16), wherein the configuration of the catalyst-coated channels (14) differ from the non-catalyst channels (16) such that, when applied in exothermic reaction processes, such as catalyst combustion, the desired reaction is promoted in the catalytic channels (14) and substantially limited in the non-catalytic channels (16). The invention further comprises an improved reaction system and process for combustion of a fuel wherein catalytic combustion using a catalyst structure employing integral heat exchange, preferably the improved structures of the invention, affords a partially-combusted, gaseous product which is passed to a homogeneous combustion zone where complete combustion is promoted by means of a flameholder.
Abstract:
A support structure (53) for securing a catalyst structure (52) comprising a multiplicity of longitudinally disposed channels for passage of a flowing gas mixture within a reactor, said support structure being comprised of a monolithic open celled or honeycomb-like structure formed by thin strips or ribs of high temperature resistant metal or ceramic which abuts against one end of the catalyst structure, and extends in a direction perpendicular to the longitudinal axis of the catalyst structure to essentially cover an end face (at either the inlet end or outlet end or both) of the catalyst structure with the support structure being secured (54) on its periphery to the reactor wall. The strips or ribs making up the support structure are bounded together to form a unitary structure having cellular openings at least as large as the catalyst structure channel openings. The cellular openings in the support structure are also positioned to be in fluid communication with the channels of the catalyst structure thus affording essentially unaltered gas flow (50) from the catalyst structure through the support structure.
Abstract:
This invention is an improved catalyst structure and its use in highly exothermic processes like catalytic combustion. This improved catalyst structure employs integral heat exchange in an array of longitudinally disposed, adjacent reaction passageways or channels, which are either catalyst-coated or catalyst-free, wherein the configuration of the catalyst-coated channels differs from the non-catalyst channels such that, when applied in exothermic reaction processes, such as catalytic combustion, the desired reaction is promoted in the catalytic channels and substantially limited in the non-catalyst channels. The invention further comprises an improved reaction system and process for combustion of a fuel wherein catalytic combustion using a catalyst structure (112) employing integral heat exchange, preferably the improved structures of the invention, affords a partially-combusted, gaseous product which is passed to a homogeneous combustion zone (114) where complete combustion is promoted by a flameholder (118) including combustion processes where extremely lean fuel/air mixtures can be employed to afford complete combustion with little or no concomitant NOx production.
Abstract:
This invention is a catalyst comprising palladium on a support (102) and a partial combustion process in which the fuel is partially combusted using that catalyst. The palladium catalyst (106) may also comprise palladium mixed with metals selected from Group VIII or IB, may be graded (Fig. 1b) such as to have higher activity in the forward edge (112) of the catalyst, or may be placed on a support comprising zirconia. The choice of catalysts (106) and supports (102, 110) specified each solves a variety of problems dealing with the long term stability of the palladium as a partial combustion catalyst. The catalyst structure is stable in operation, has a comparatively low operating temperature, has a low temperature at which oxidation begins, and yet is not susceptible to temperature "runaway". The combustion gas produced by the catalytic process typically is at a temperature below the autocombustive temperature and may be used at that temperature or it may be fed to other combustion stages for further use in a gas turbine, furnace, boiler, or the like.
Abstract:
The invention relates to an electrically heated catalyst (EHC, 10) and a start-up method of a gas turbine engine employing an EHC (10) in the combustor (33). The catalyst (10) is electrically heated to a predetermined temperature prior to start up of the turbine system and is turned off when any one of several conditions are met, e.g. the heat of catalytic reaction is sufficient to maintain the catalyst (10) in its steady state condition. The EHC (10) is made of stacked or spirally wound foils (12, 14).
Abstract:
This invention is an improved catalyst structure and its use in highly exothermic processes like catalyst combustion. This improved catalyst structure employs integral heat exchange in an array of longitudinally disposed, adjacent reaction passageways or channels, which are either catalyst-coated (14) or catalyst-free (16), wherein the configuration of the catalyst-coated channels (14) differ from the non-catalyst channels (16) such that, when applied in exothermic reaction processes, such as catalyst combustion, the desired reaction is promoted in the catalytic channels (14) and substantially limited in the non-catalytic channels (16).
Abstract:
This invention is a combustion process having a series of stages in which a fuel/oxygen-gas-containing mixture (16, 18) is combusted stepwise using a series of specific catalysts and catalytic structures (figure 2) and, optionally, a final homogeneous combustion zone to produce a combusted gas at a selected temperature preferably between 1050 DEG and 1700 DEG C. Depending upon the pressure of operation, there may be two or three discrete catalytic stages (stages 1, 2 and 3). The choice of catalysts and the use of specific structures, including those employing integral heat exchange (44) results in a catalyst and its support which are stable due to their comparatively low temperature, do not deteriorate, and yet the product combustion gas is at a temperature suitable for use in a gas turbine, furnace, boiler, or the like, but has low NOx content. Neither fuel nor air is added to the combustion process except in the initial stage.
Abstract:
This invention is a catalyst structure having integral heat exchange surfaces. This feature allows use of the structure in highly exothermic process, such as a combustion process, while maintaining the catalyst and the structure wall at a temperature below the adiabatic combustion temperature of the combustible gas.