Abstract: By adding an opaque ecliptic half-plane (24) to a partially open or transparent equatorial disk (12) which bears a sidereal hours scale (20), and by being able to rotate this plane (24) and disk (12) jointly in order to minimize the shadow being cast (74) by ecliptic half-plane (24), one can easily determine the local sidereal time using the sun. Understanding its operation draws on a number of basic concepts that a beginning astronomy student should master, and should also interest sundial enthusiasts.

Abstract: The present invention is a process for regenerating a sulfur-contaminated, highly selective, large-pore zeolite catalyst. It comprises a multistep process involving exposure of the catalyst to a combination of oxidizing conditions, reducing conditions and treatment with a halogen acid gas. These conditions are effective to agglomerate a Group VIII metal and remove sulfur. Thereafter, the catalyst is oxychlorinated to redisperse the Group VIII metal over the catalyst surface. A carbon removal step is optionally included.

Abstract: A new catalyst is disclosed which is useful for dehydrocyclizing alkanes. This catalyst contains a zeolite of the L family, a Group VIII metal, and an alkaline earth metal.

Abstract: A new catalyst is disclosed which is useful for dehydrocyclizing alkanes. This catalyst contains a type L zeolite, a Group VIII metal, and an alkaline earth metal. Preferably, this catalyst contains a type L zeolite, from 0.1% to 5% by weight platinum and from 1% to 20% by weight barium.

Abstract: A method of dehydrocyclizing alkanes is disclosed wherein the alkanes are contacted with a catalyst containing a large-pore zeolite, a Group VIII metal, and an alkaline earth metal wherein the Selectivity Index is greater than 60%.

Abstract: A new catalyst is disclosed which is useful for dehydrocyclizing alkanes. This catalyst contains a zeolite of the L family, a Group VIII metal, and an alkaline earth metal.

Abstract: A hydrocarbon conversion process is disclosed wherein the alkanes are contacted with a catalyst containing a metallic oxide support and a Group VIII metal, and with a catalyst containing a large-pore zeolite, a Group VIII metal, and an alkaline earth metal.

Abstract: A new catalyst is disclosed which is useful for dehydrocyclizing alkanes. This catalyst contains a type L zeolite, a Group VIII metal, and an alkaline earth metal. Preferably, this catalyst contains a type L zeolite, from 0.1% to 5% by weight platinum and from 1% to 20% by weight barium.

Abstract: A method of dehydrocyclizing alkanes is disclosed wherein the alkanes are contacted with a catalyst containing a large-pore zeolite, a Group VIII metal, and an alkaline earth metal wherein the Selectivity Index is greater than 60%.

Abstract: A catalytic conversion system having sulfur-contaminated vessels and/or conduits upstream from the fixed catalytic bed is regenerated in situ by first flowing regenerating oxygen-containing gas having not more than 0.1 mol percent oxygen and at a temperature of above 850.degree. F., through the normal flow path of the vessels and/or conduits and then the fixed catalyst beds, wherein the sulfur contaminants are oxidized to sulfur dioxide which pass through the catalyst bed in the absence of sufficient oxygen to permit substantial conversion to harmful sulfur trioxide in the presence of catalyst containing a platinum group component on a porous inorganic oxide base, prior to removal of carbonaceous material from the catalyst.

Abstract: A method is disclosed for regenerating reforming catalysts containing a platinum group component and/or rhenium component in association with a halogen component on a porous inorganic oxide, such as one containing alumina without significant displacement of the rhenium components by sulfur oxides generated during the regeneration process. The method is particularly characterized in that carbon is removed from the catalyst by in situ oxidation at temperatures not in excess of about 750.degree. F. and without modification of the catalytic reforming process flow circuit, as by disconnecting or isolating the heat exchangers and furnace tubes.Sulfide scale is converted in a separate oxidation step to sulfur dioxide, SO.sub.2, without substantial oxidation to sulfur trioxide, SO.sub.3, by maintaining the inner walls of the heat exchangers and furnace tubes, where such iron sulfides are present, at a temperature not in excess of about 900.degree. F. and not less than about 750.degree. F.

Abstract: In a process for reforming light naphtha with a bimetallic or multimetallic reforming catalyst, such as a platinum-rhenium-halogen catalyst, at conventional reforming conditions, wherein the catalyst is used for an extended continuous on-stream period, the aromatics selectivity of the catalyst is rapidly increased by contacting the naphtha and hydrogen with the catalyst at increased severity operating conditions, such as a reduced pressure less than 90% of the normal reforming pressure, during an initial portion of the on-stream period.

Abstract: A method of dehydrocyclizing alkanes is disclosed wherein the alkanes are contacted with a catalyst containing a large-pore zeolite, a Group VIII metal, and an alkaline earth metal. The amount of Group VIII metal and the amount of alkaline earth metal present in the catalyst are adjusted so that the selectivity for n-hexane of the dehydrocyclization reaction is greater than 60%.

Abstract: A method is disclosed for the dehydroisomerization of alkylcyclopentanes using a catalyst comprising a large-pore zeolite, a Group VIII metal, and an alkaline earth metal.

Abstract: A straight-run naphtha is fractionated at about 66.degree. C., which is just below the boiling point of methylcyclopentane. The 66.degree. C.+ fraction is reformed, and at least a portion of the reformate combined with the 66.degree. C.- fraction and reacted under aromatization conditions over a ZSM-5-type catalyst to form a C.sub.5 + product rich in aromatics. The C.sub.5 + aromaticized product and the remaining reformate can be either sent for BTX recovery or used as a high-octane component of a gasoline blending pool.

Abstract: A straight-run naphtha is fractionated into a light naphtha fraction and a heavy naptha fraction containing methylcyclopentane and heavier hydrocarbons. The heavy fraction is reformed and the C.sub.5 -C.sub.6 paraffin portion of the reformate combined with the light naphtha fraction for isomerization. The heavy reformate is converted over a ZSM-5-type catalyst to produce a product enriched in aromatics which may be sent for BTX recovery or to a gasoline pool as a high-octane gasoline blending stock.

Abstract: A hydrocarbon feed containing an olefinic component and sulfur-containing impurities is upgraded in a sulfur removal process without hydrogenating the olefins by contacting a mixture of the feed and hydrogen gas with a catalyst comprising copper under conditions, including a temperature in the range of about 120.degree. C to 400.degree. C.

Abstract: The present invention is a process for regenerating a sulfur-contaminated, highly selective, large-pore zeolite catalyst. It comprises a multistep process involving exposure of the catalyst to a combination of oxidizing conditions, reducing conditions and treatment with a halogen acid gas. These conditions are effective to agglomerate a Group VIII metal and remove sulfur. Thereafter, the catalyst is oxychlorinated to redisperse the Group VIII metal over the catalyst surface. A carbon removal step is optionally included.