Catalyst regeneration with impregnation of bismuth and molybdenum
AssigneeE. I. Du Pont de Nemours and Company
InventorsMichael Brian D'Amore, Arthur William Sleight
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Abstract
Process for regenerating a spent catalyst, which catalyst contains potassium, cobalt, nickel, iron, bismuth, phosphorus and molybdenum and sufficient oxygen to satisfy the valence of the other elements therein, on a support, e.g. silicon oxide, wherein at least a portion of the molybdenum has been lost during ammoxidation, comprising impregnating said catalyst with bismuth and molybdenum in solution so that at least some of the molybdenum lost is replaced, e.g., a typical impregnating solution is prepared by dissolving molybdenum trioxide and phosphoric acid in water, adding nitric acid and finally dissolving bismuth nitrate pentahydrate in the resultant solution.
Claims14
A process for regenerating a catalyst of the general formula A.sub.a B.sub.b C.sub.c Fe.sub.d Bi.sub.e Mo.sub.f O.sub.x wherein A is at least one element selected from the group consisting of an alkali metal, rare earth metal, tantalum and niobium, B is at least one element selected from the class consisting of nickel and cobalt, C is at least one element selected from the class consisting of phosphorus and arsenic, "a" and "c" are numbers from 0 to 3, "b" is a number from 0.1 to 20, "d" is a number from 0.1 to 8, "e" is a number from 0.1 to 6, "f" is a number from 8 to 16, and "x" is a number determined by the valence requirements of the other elements present, wherein said catalyst has become at least partially deactivated by exposure to ammoxidation conditions which exposure is accompanied by the loss of a portion of the molybdenum originally present in the catalyst, which process comprises impregnating said catalyst with molybdenum and bismuth, separating the catalyst thus impregnated from any bismuth and molybdenum not absorbed by the catalyst and thereafter calcining the catalyst by heating the catalyst to a temperature in the range of about 300.degree.-700.degree. C in an oxidizing atmosphere to form a regenerated catalyst wherein the mole ratio of added molybdenum to bismuth is in the range 0.5-20 and at least 50% of the molydbenum lost is replaced.
A process for the regeneration of a spent ammoxidation catalyst consisting essentially of potassium, cobalt, nickel, iron, bismuth, phosphorus and molybdenum and sufficient oxygen to satisfy the valences of the other elements therein, on a support wherein said catalyst has become at least partially deactivated by exposure to ammoxidation conditions which exposure is accompanied by a loss of molybdenum from the catalyst which process comprises impregnating said catalyst with bismuth and molybdenum in substantially aqueous solution and wherein the mole ratio of added molybdenum to bismuth is maintained in the range 0.5 to 20, until at least 50% of the molybdenum lost is replaced separating the catalyst thus treated from any solution not absorbed on the catalyst and thereafter calcining the catalyst by heating the catalyst to a temperature in the range of about 300.degree.-700.degree. C in an oxidizing atmosphere to obtain a regenerated catalyst.
A process for regenerating an ammoxidation catalyst initially having the general formula K.sub.(g) Co.sub.(h) Ni.sub.(i) Fe.sub.(j) Bi.sub.(k) P.sub.(l) Mo.sub.(m) O.sub.(x) wherein (g) through (m) are numbers in the range of 0.05-0.10, 4.0-5.0, 2.0-3.0, 2.5-3.5, 0.8-1.2, 0.1-1.0, 10.8-13.2, respectively, and wherein (x) is sufficient to satisfy the valence requirements of the other elements present and wherein said catalyst has lost from about 0.4 to about 1.2 moles of molybdenum as expressed in the above formula by exposure to ammoxidation, which comprises impregnating said catalyst with an aqueous solution comprising bismuth and molybdenum species until at least about 1.5 weight percent molybdenum and 0.56 weight percent bismuth, based upon the weight of the catalytic elements, is incorporated onto the surfaces of said catalyst, separating the catalyst thus treated from any solution not absorbed by the catalyst and thereafter calcining the catalyst by heating the catalyst to a temperature in the range of about 300.degree.-700.degree. C in an oxidizing atmosphere to obtain a regenerated catalyst.
A process for regenerating an ammoxidation catalyst which catalyst comprises the combined oxides of potassium, cobalt, nickel, iron, bismuth, phosphorus and molybdenum on a silicon oxide support and in powder form, wherein said catalyst has become at least partially deactivated by exposure to ammoxidation conditions said process comprising thoroughly contacting said catalyst with a solution prepared by dissolving sufficient molybdenum trioxide and phosphoric acid in water to provide a solution having at least 29 grams/liter of molybdenum and at least 0.8 gram/liter of phosphorus, adding nitric acid and finally dissolving sufficient bismuth nitrate pentahydrate in the resultant solution to provide a solution having at least 11 grams/liter of bismuth, separating the catalyst from any solution not absorbed therein and calcining the catalyst thus treated at a temperature in the range 450.degree.-650.degree. C in an oxidizing atmosphere to form an active catalyst.
Dependencies are inferred from the claim text.