Hydrocarbon conversion process utilizing a magnetic field in a fluidized bed of catalytic particles

Abstract

A hydrocarbon conversion process, such as catalytic desulfurization of a vaporized petroleum feedstock with hydrogen or catalytic reforming of a vaporized hydrocarbon feedstock, is carried out by passing the gaseous medium upwardly through a fluidized bed of magnetizable composite particles having catalytic activity for hydrocarbon conversion and which contain 2 to 40 volume % ferro- or ferrimagnetic material .[.to.]. .Iadd.in .Iaddend.a nontime varying (direct current) and substantially uniform applied magnetic field having a substantial component along the direction of gravity such that the composite particles have a component of magnetization along the direction of gravity. The gaseous medium is also the fluidizing medium passing upwardly at a superficial gas velocity ranging between: (1) at least twice the normal minimum superficial gas velocity required to fluidize the bed in the absence of said applied magnetic field, and (2) less than the superficial gas velocity required to cause time-varying fluctuations of pressure difference through said bed for a 0.1 to 1 second time interval during continuous fluidization in the presence of said applied magnetic field.

What is claimed is: .[.1. A fluidized hydrocarbon conversion process which comprises: 
       (a) subjecting a fluidized bed comprised of magnetizable, fluidizable composite particles which have catalytic activity for hydrocarbon conversion and which contain 2 to 40 volume % ferro- or ferrimagnetic material to a nontime varying and substantially uniform applied magnetic field having a substantial component along the direction of gravity such that said composite particles have a component of magnetization along the direction of gravity, and 
       (b) passing a fluidizing gaseous medium comprising a vaporized hydrocarbon feedstock upwardly through said bed at a superficial gas velocity ranging between: 
       (i) at least 10% greater than the normal minimum superficial gas velocity required to fluidize the bed in the absence of said applied magnetic field; and 
       (ii) less than the superficial gas velocity required to cause time-varying fluctuations of pressure difference through said bed for a 0.1 to 1 second time interval during continuous fluidization in the presence of said applied magnetic field..]. .[.2. The process of claim 1 wherein said fluidizing gaseous medium includes hydrogen..]. .[.3. The process of claim 1 wherein said fluidized bed is at a temperature of 500°-800° F., said fluidizing gaseous medium comprises a vaporized petroleum feedstock and hydrogen and said magnetizable, fluidizable composite particles are catalytically active for the catalytic desulfurization of said feedstock..]. .[.4. The process of claim 3 wherein at least a portion of said bed is subjected to a substantially uniform applied magnetic field of at least 100 oersteds oriented axially to the flow of gas in the fluidized bed zone and wherein said magnetizable, fluidizable composite particles have a magnetization of at least 150 gauss..]. .[.5. The process of claim 1 wherein said fluidized bed is at a temperature of 800°-1100° F. and said magnetizable, fluidizable composite particles are catalytically active for the catalytic reforming of said feedstock..]. .[.6. The process of claim 1 wherein the uppermost 20-40% region or zone of the bed is stabilized by the applied magnetic field..]. .Iadd. 7. A process for carrying out a hydrocarbon conversion of a fluid stream of a hydrocarbon feedstock in a fluidized bed, which process comprises: 
       (a) carrying out said hydrocarbon conversion process under hydrocarbon conversion conditions, passing said stream through at least one controllably transported hydrocarbon conversion fluidized bed containing magnetizable composite particles which contain 2 to 40 volume % ferro- or ferrimagnetic material, said bed of particles being expanded and levitated by said stream, and 
       (b) controllably transporting said bed in response to a pressure differential in said bed, wherein at least a portion of said bed is subjected to an applied magnetic field having a substantial component along the direction of the external force field within said bed at a strength such that gross solids backmixing and fluid by-passing in said bed are suppressed but less than that which impairs the fluid-like properties of the bed. .Iaddend..Iadd. 8. The process of claim 7 wherein said stream in-includes hydrogen. .Iaddend..Iadd. 9. The process of claim 7 wherein said fluidized bed is at a temperature ranging from 500° to 800° F., said stream comprises a vaporized petroleum feedstock and hydrogen and said magnetizable particles are catalytically active for the catalytic desulfurization of said feedstock. .Iaddend..Iadd. 10. The process of claim 9 wherein at least a portion of said bed is subjected to a substantially uniform applied magnetic field of at least 100 oersteds oriented axially to the flow of said fluidizing stream and wherein said magnetizable particles have a magnetization of at least 150 gauss. .Iaddend. .Iadd. 11. The process of claim 7 wherein said fluidized bed is at a temperature ranging from 800° to 1100° F. and said magnetizable particles are active for the catalytic reforming of said feedstock. .Iaddend..Iadd. 12. The process of claim 11 wherein at least a portion of said bed is subjected to a substantially uniform applied magnetic field of at least 100 oersteds oriented axially to the flow of said fluidizing stream and wherein said magnetizable particles have a magnetization of at least 150 gauss. .Iaddend..Iadd. 13. The process of claim 7 wherein said external force field is gravity. .Iaddend..Iadd. 14. The process of claim 7 wherein said fluid stream is gaseous. .Iaddend..Iadd. 15. The process of claim 7 wherein said bed additionally contains nonmagnetizable particles. .Iaddend..Iadd. 16. The process of claim 7 wherein said composite particles include a zeolitic material. .Iaddend..Iadd. 17. The process of claims, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 wherein said applied magnetic field is nontime-varying and substantially uniform. .Iaddend..Iadd. 18. The process of claims 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 wherein said applied mangetic field is time-varying and substantially uniform and wherein said magnetizable particles have a zero or relatively low coercivity. .Iaddend. .Iadd. 19. The process of claims 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16, wherein the superficial fluid velocity of said fluid stream ranges between: 
       (1) more than the normal fluidization superficial fluid velocity required to expand and levitate said bed in the absence of said applied magnetic field; and 
       (2) less than the superficial fluid velocity required to cause time-varying fluctuations of pressure difference through said expanded and levitated bed over a finite period of time during continuous operation in the presence of said applied magnetic field. .Iaddend..Iadd. 20. The process of claim 7 wherein the uniformity of said applied magnetic field is such that the ratio of the local intensity of the applied magnetic field to the mean field varies by no more than 5% over the region of the bed containing magnetizable particles. .Iaddend..Iadd. 21. The process of claim 7 wherein said bed medium is transported in a plug-flow manner. .Iaddend..Iadd. 22. The process of claim 7 wherein said bed medium is transported from one vessel to another vessel. .Iaddend..Iadd. 23. The process of claims 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16, wherein said bed is bubbling. .Iaddend..Iadd. 24. The process of claim 23 wherein said applied magnetic field is nontime-varying and substantially uniform. .Iaddend..Iadd. 25. The process of claim 23 wherein said applied magnetic field is time-varying and substantially uniform and wherein said magnetizable particles have a zero or relatively low coercivity. .Iaddend. .Iadd. 26. A process for carrying out a hydrocarbon conversion of a fluid stream of a hydrocarbon feedstock in a fluidized bed, which process comprises: 
       (a) carrying out said hydrocarbon conversion process under hydrocarbon conversion conditions, passing said stream through at least one controllably transported hydrocarbon conversion fluidized bed containing an admixture of magnetizable and catalytic particles, said bed of particles being expanded and levitated by said stream, and 
       (b) controllably transporting said bed in response to a pressure differential in said bed, wherein at least a portion of said bed is subjected to an applied magnetic field having a substantial component along the direction of the external force field within said bed at a strength such that gross solids backmixing and fluid by-passing in said bed are suppressed but less than that which impairs the fluid-like properties of the bed. .Iaddend.