Abstract: An improved process for calcination and activation of a catalyst containing mixed oxides of vanadium and phosphorus (V/P/O) comprising the steps of calcining a hydrated V/P/O or V/P/O- SiO.sub.2 catalyst precursor at a temperature range of 375.degree. to 400.degree. C. for sufficient time to dehydrate said catalyst precursor while simultaneously and continuously controlling the oxygen level such as to maintain the Vox in the range of 3.825 to 4.175; and then activating the dehydrated catalyst precursor by further heating at a range of 340.degree. to 500.degree. C. in the presence of a gaseous atmosphere containing n-butane at a partial pressure not exceeding 0.20 atm while simultaneously and continuously controlling the oxygen level such as to maintain the Vox in the range of 3.95 to 4.15. Such a V/P/O catalyst is useful in the preparation of maleic anhydride from n-butane.

Abstract: An improved process for selective vapor phase oxidation of n-butane to maleic anhydride involving the use of a recirculating solids reactor having a reaction zone and a catalyst regeneration zone wherein n-butane is converted to maleic acid in the reaction zone by use of a vanadium/phosphorous oxide (V/P/O) catalyst in oxidized form and the reduced vanadium/phosphorous oxide catalyst is regenerated by contact with oxygen in the regeneration zone. Replenishment of the inherent catalyst losses associated with the catalyst recycling process is accomplished by adding to the catalyst in the regeneration zone vanadium/phosphorous oxide catalyst precursor at a rate of addition that effectuates in situ calcination and activation of the vanadium/phosphorous oxide catalyst precursor while simultaneously maintaining the desired operating temperature of the n-butane to maleic anhydride conversion reaction. Such a process is useful in maintaining the high operating capacity of the reactor over an extended period of time.

Abstract: The oxidation of butane to maleic anhydride in a recirculating solids reactor using a stoichiometric excess of oxygen, a vanadium-phosphorus oxide catalyst in oxidized form, and separate regeneration of the resultant reduced catalyst is disclosed.

Abstract: Oxidation of butane to maleic anhydride using a vanadium-phosphorus oxide catalyst, in oxidized form, wherein the resulting reduced catalyst is separately regenerated. A recirculating solids reactor can be employed. Less than the stoichiometric amount of oxygen, based on the total amount of butane converted, can be employed.

Abstract: Apparatus for depositing staple fibers onto a conveyor belt to form a batt, including a chute feeder having an adjustable weir plate provided with a row of air jets along the bottom edge for maintaining a uniform fiber level at the exit from the chute. Fibers are supplied in an air stream from which they are separated by condenser means and fall into the chute over distributing baffles.

Abstract: Process and apparatus are disclosed which are suitable for high speed production of uniform, lightweight webs by air-laydown of textile fibers. A toothed disperser roll doffs the fibers into an air stream of high uniform velocity and low turbulence to form a thin fiber stream from which the fibers are deposited in web form on a moving screen. A curved disperser plate, shrouds the disperser roll and prevents premature doffing. By using a disperser plate with a rough surface, preferably one having lateral grooves, web uniformity is remarkably improved.