The present disclosure relates generally to catalyst materials and processes for making and using them. More particularly, the present disclosure relates to molybdenum, bismuth and iron-containing metal oxide catalyst materials useful, for example, in the partial oxidation or ammoxidation of propylene or isobutylene, processes for making them, and processes for making acrolein, methacrolein, acrylonitrile, and methacrylonitrile using such catalysts.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A heat removal tube set, and application of the same for controlling the temperature of a fluidized bed reactor and for producing an unsaturated nitrile are provided. The heat removal tube set has at least one first heat removal tube and at least one second heat removal tube, wherein the ratio of the total circumference Lb of the outer contours of all of the straight pipes b of the second heat removal tube on the cross section to the total circumference La of the outer contours of all of the straight pipes a of the first heat removal tube on the cross section is greater than 1 and less than 1.25. When the first heat removal tube and the second heat removal tube are switched coordinatively in a paired manner, the reaction temperature can be maintained substantially constant.

A heat removal tube set, and application of the same for controlling the temperature of a fluidized bed reactor and for producing an unsaturated nitrile are provided. The heat removal tube set has at least one first heat removal tube and at least one second heat removal tube, wherein the ratio of the total circumference Lb of the outer contours of all of the straight pipes b of the second heat removal tube on the cross section to the total circumference La of the outer contours of all of the straight pipes a of the first heat removal tube on the cross section is greater than 1 and less than 1.25. When the first heat removal tube and the second heat removal tube are switched coordinatively in a paired manner, the reaction temperature can be maintained substantially constant.

A heat removal tube set, a method for controlling reaction temperature using the heat removal tube set, and a method for producing an unsaturated nitrile are provided. The heat removal tube set has at least one first heat removal tube and at least one second heat removal tube. The number of all straight pipes a of the first heat removal tube is the same as that of all straight pipes b of the second heat removal tube. The ratio of the total circumference Lb of the outer contours of all of the straight pipes b of the second heat removal tube on the cross section to the total circumference La of the outer contours of all of the straight pipes a of the first heat removal tube on the cross section is 1.25-2. When the first heat removal tube and the second heat removal tube are switched coordinatively in a paired manner, a fine adjustment of the reaction temperature can be realized.