The catalyst for ammoxidation of the present invention contains a catalyst particle containing molybdenum, bismuth and iron, and has a ratio of hollow particles of 23% or less. Furthermore, a method for producing the catalyst for ammoxidation includes a step of preparing a catalyst precursor slurry containing molybdenum, bismuth and iron and having a solid concentration of 30% by mass or less, a step of spray-drying the catalyst precursor slurry at a drier inlet temperature of 120 C. to 240 C. to thereby obtain a dried particle and a step of calcining the dried particle at 500 to 750 C.

The catalyst for ammoxidation of the present invention contains a catalyst particle containing molybdenum, bismuth and iron, and has a ratio of hollow particles of 23% or less. Furthermore, a method for producing the catalyst for ammoxidation includes a step of preparing a catalyst precursor slurry containing molybdenum, bismuth and iron and having a solid concentration of 30% by mass or less, a step of spray-drying the catalyst precursor slurry at a drier inlet temperature of 120 C. to 240 C. to thereby obtain a dried particle and a step of calcining the dried particle at 500 to 750 C.

The present invention relates to an impregnated supported catalyst, a carbon nanotube aggregate, and a method for producing the carbon nanotube aggregate. The carbon nanotube aggregate includes a four-component catalyst in which catalytic components and active components are supported on a granular support, and bundle type carbon nanotubes grown on the catalyst. The carbon nanotube aggregate has an average particle diameter of 100 to 800 m, a bulk density of 80 to 250 kg/m.sup.3, and a spherical or potato-like shape.

A method for producing at least one oxidation product selected from the group consisting of acrolein and acrylic acid is provided. This method can alleviate concerns about deterioration of a gas-phase oxidation catalyst and reaction runaway in a restart period after a shutdown, and can allow the reaction to proceed in a stable state. Using a fixed-bed reactor filled with a gas-phase oxidation catalyst, at least one source gas selected from the group consisting of propylene and acrolein is subjected to a gas-phase contact oxidation reaction while a heating medium is caused to contact with or circulate through the fixed-bed reactor and thereby to heat the fixed-bed reactor. The temperature of the heating medium when the load is maximum in the restart period after the shutdown is controlled to be lower than the temperature of the heating medium when the load is maximum in an initial start-up period.

The present invention provides a catalyst including Mo, Bi, and Fe, wherein P/R is 0.10 or less, wherein P is a peak intensity at 2=22.90.2 and R is a peak intensity at 2=26.60.2, in X-ray diffraction analysis.

A process for preparing a catalyst comprises coating substantial internal surfaces of porous inorganic powders with titanium oxide to form titanium oxide-coated inorganic powders. After the coating, an extrudate comprising the titanium oxide-coated inorganic powders is formed and calcined to form a catalyst support. Then, the catalyst support is impregnated with a solution containing one or more salts of metal selected from the group consisting of molybdenum, cobalt, and nickel.

Oxidative dehydrogenation is an alternative to the energy extensive steam cracking process presently used for the production of olefins from paraffins, but has not been implemented commercially partially due to the unstable nature of hydrocarbon/oxygen mixtures, and partially due to the cost involved in the construction of new facilities. An oxidative dehydrogenation chemical complex designed to reduce costs by including integration of an oxygen separation module that also addresses safety concerns and reduces emission of greenhouse gases is described.

An object of the present invention is to provide a catalyst ensuring that when a gas-phase catalytic oxidation reaction of a material substance is conducted using a catalyst to produce a target substance, the pressure loss and coking are suppressed and the target substance can be produced in high yield. The present invention is related to a ring-shaped catalyst having a straight body part and a hollow body part, which is used when a gas-phase catalytic oxidation reaction of a material substance is conducted to produce a target substance, wherein a length of the straight body part is shorter than a length of the hollow body part and at least at one end part, a region from an end part of the straight body part to an end part of the hollow body part is concavely curved.

An object of the present invention is to suppress performance deterioration of a molybdenum composite oxide-based catalyst at the time of performing gas-phase catalytic partial oxidation with molecular oxygen by using a tubular reactor. The present invention relates to a catalytic oxidation method using a tubular reactor in which a Mo compound layer containing a Mo compound and a composite oxide catalyst layer containing a Mo composite oxide catalyst are arranged in this order from a reaction raw material supply port side and under a flow of a mixed gas containing 75 vol % of air and 25 vol % of water vapor at 440 C., a Mo sublimation amount of the Mo compound is larger than a Mo sublimation amount of the Mo composite oxide catalyst under the same conditions.

An industrial furnace and a method for roasting or regenerating spent petroleum catalysts. The furnace particularly includes a device to set the catalysts in motion along the bottom of the furnace to cause the catalysts to circulate from the inlet towards the outlet of the furnace; a first zone decarbonizing the spent catalysts to obtain decarbonized catalysts, followed by: a second zone including a plurality of oxygen feed devices distributed along the length of the second zone and placing the decarbonized catalysts in contact with the oxygen feed, the second zone desulfurizing the decarbonized catalysts to obtain roasted or regenerated catalysts.