摘要:
A hydrocarbon gas such as methane and LPG is desulfurized in the presence of oxygen and an oxidation catalyst to convert sulfur compounds in the gas to sulfur oxides. The sulfur oxides are then trapped downstream of the oxidation by an adsorbent. The amount of oxygen added to the hydrocarbon gas to promote oxidation is such that the sulfur compounds are selectively oxidized and the oxidation of the hydrocarbon gas is minimized to reduce hydrogen formation.
摘要:
Provided is a method of generating a hydrogen-rich reformate from a hydrocarbon feed stream comprising olefins and alkanes (e.g., LPG). An inlet gas stream containing the hydrocarbon feed stream and an oxygen containing gas stream, is preheated to a temperature of from 180 to 300° C. The preheated inlet gas stream is then contacted with a sulfur tolerant partial oxidation catalyst to form a pre-reformed gas stream, which is preferably maintained below about 400° C. The pre-reformed gas stream is then subjected to a reforming process to form the hydrogen-rich reformate.
摘要:
The invention pertains to the preparation and use of catalytic materials and catalyst members for the selective oxidation of carbon monoxide in a gas stream that contains hydrogen. One such catalyst member may be produced by depositing by electric arc spraying a metal feedstock onto a metal substrate to provide a metal anchor layer on the substrate, and depositing a catalytic material comprising platinum and iron dispersed on a refractory inorganic oxide support material onto the metal substrate. The catalytic material may optionally be produced by wetting the support material, especially a particulate support material, with a platinum group metal solution and iron solution and drying and calcining the wetted support material in air at a temperature in the range of from 200° C. to 300° C., preferably using a solution containing bivalent platinum ion species. The catalyst member may be used by flowing the gas stream therethrough at a temperature at about 90° C. with a O2:CO ratio of about 1:1 and a space velocity of about 20,000/hr or, alternatively, at a temperature of about 150° C. with a O2:CO ratio of about 1.5:1 and a space velocity of about 80,000/hr.
摘要:
Oxidation catalyst compositions for treating diesel exhaust include ceria and, optionally, alumina, each having a surface area of at least about 10 m2/g, and a zeolite, e.g., Beta zeolite. Optionally, platinum may be included in the catalytic material, preferably in amounts which are sufficient to promote some gas-phase oxidation of carbon monoxide (“CO”) and hydrocarbons (“HC”) but which are limited to preclude excessive oxidation of SO2 to SO3. Alternatively, palladium in any desired amount may be included in the catalytic material. The zeolite is optionally doped, e.g., ion-exchanged, with one or more of hydrogen, a platinum group metal or other catalytic metals. The catalyst compositions may be used in a method to treat diesel engine exhaust by contacting the hot exhaust with the catalyst composition to promote the oxidation of gas-phase CO and HC and of the volatile organic fraction component of particulates in the exhaust.
摘要:
A method for reducing gaseous nitrogen oxides present in a gas stream by reaction with a reductant species is practiced by flowing the gas stream under lean NO.sub.X -reducing conditions in contact with a catalytic material containing a catalytically effective amount of a catalytic species, e.g., a platinum group metal, and a reductant storage material, e.g., a zeolite, effective for storing reductant species for reaction with NO.sub.X, and providing an intermittent supply of the reductant to the gas stream. The catalytic material may be prepared in any manner, but one method is to incorporate a catalytically effective amount of the platinum into a template-bearing molecular sieve material, preferably ZSM-5, to hinder the platinum from being incorporated into the pores of the molecular sieve material, and then calcining the molecular sieve material, whereby the template is removed from the molecular sieve material after the platinum is incorporated therein. Another method is to add a blocking agent to the molecular sieve material, then incorporate the platinum therein, and then calcine the material to remove the blocking agent. The catalytic material may contain less than about two percent by weight of zeolite plus platinum, e.g., less than about 0.5%, or from about 0.025% to 0.1% or 0.2% platinum.
摘要:
A method of at least periodically removing from a lean gaseous stream a sorbable component such as SO.sub.x includes passing the gaseous stream through a trap member having an oxidation catalyst combined with a sorbent material at a temperature within the sorbing temperature range of the sorbent material. The sorbed component is periodically removed by introducing a combustible component into the gaseous stream and oxidizing it on the trap member to thermally desorb the sorbed component. The amount of combustible component introduced is limited to maintain the gaseous stream composition lean, but is sufficient to increase the surface temperature of at least part of the trap member to above the bulk temperature of the gaseous stream. Sorbing and desorbing periods are alternated and a composition and an apparatus to carry out the process is provided.
摘要:
Oxidation catalyst compositions-include a catalytic material containing ceria-and alumina each having a surface area of at least about 10 m.sup.2 /g, for example, ceria and activated alumina in a weight ratio of from about 1.5:1 to 1:1.5. Optionally, platinum may be included in the catalytic material in amounts which are sufficient to promote gas phase oxidation of CO and HC but which are limited to preclude excessive oxidation of SO.sub.2 to SO.sub.3. Alternatively, palladium in any desired amount may be included in the catalytic material. The catalyst compositions have utility as oxidation catalysts for pollution abatement of exhausts contianing unburned fuel or oil. For example, the catalyst compositions may be used in a method to treat diesel engine exhaust by contacting the hot exhaust with the catalyst composition to promote the oxidation of the volatile organic fraction component of particulates in the exhaust.
摘要:
A combustor for supporting the catalytic combustion of a gaseous carbonaceous fuel/air combustion mixture contains a catalyst zone in which is disposed a catalyst body comprising at least a first and a second catalyst member and further contains a downstream zone where homogeneous combustion occurs. Each catalyst member is comprised of a carrier body having a catalyst material deposited thereon. The first carrier is made of a silica-magnesia-alumina material comprised primarily of cordierite, mullite and corundum and the second carrier is made of a ceramic fiber matrix material comprising ceramic (alumina-boron oxide-silica) fibers in a silicon carbide matrix.
摘要:
A process for hydrodehalogenating halogenated organic compounds present in a contaminated aqueous environmental source in which the halogenated organic compounds are reacted with hydrogen gas or a source of hydrogen gas in the presence of a catalyst of palladium on carbon.
摘要:
A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.