Process for operating a magnetically stabilized fluidized bed

• US RE31,439 E
• Filed: 09/24/1980
• Issued: 11/15/1983
• Est. Priority Date: 10/11/1974
• Status: Expired due to Term

• Current Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Original Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Inventors: Rosensweig, Ronald E.
• Primary Examiner(s): Schwartz, Larry I.
• Application Number:
  US06/190,934
• Time in Patent Office: 1,147 Days
• Field of Search: 34/1, 34/10, 34/57 A, 423/DIG. 16, 423/659, 110/245, 406/89, 406/90, 366/101, 366/106, 366/107, 366/273, 366/274, 252/411 R, 432/15, 432/58, 422/143, 422/139, 422/141
• US Class Current: 34/249
• CPC Class Codes: B01J 8/42 with fluidised bed subjected to electric current or to radiations this sub-group includes the fluidised bed subjected to electric or magnetic fields
• CPC Class Codes: F26B 3/097 using a magnetic field to stabilise the fluidised bed

Abstract

A fluidized bed process is disclosed which comprises subjecting a bed comprised of solid particulate magnetizable, fluidizable material within an external force field wherein at least a portion of the bed containing said solid particulate magnetizable and fluidizable material and fluidizing fluid are subjected to a nontime varying and substantially uniform applied magnetic field having a substantial component along the direction of the external force field such that said solid particulate magnetizable and fluidizable material has a component of magnetization along the direction of the external force field and wherein at least a portion of said bed containing the solid particulate magnetizable and fluidizable material is fluidized by a flow of fluid opposing said external force field at a superficial fluid velocity ranging between:

(a) more than the normal minimum fluidization superficial fluid velocity required to fluidize said bed in the absence of said applied magnetic field; and,

(b) less than the superficial fluid velocity required to cause time-varying fluctuations of pressure difference through said stably fluidized bed portion during continuous fluidization in the presence of said applied magnetic field. The strength of the magnetic field and its deviation from a vertical orientation are maintained so as to prevent and/or suppress the formation of bubbles in the fluidized media at a given fluid flow rate and with a selected fluidized particles makeup.

Fluid throughput rates which are up to 10 to 20 or more times the flow rate of the fluidized bed at incipient fluidization in the absence of the applied magnetic field are achieved, concomitant with the substantial absence of bubbles. The magnetically stabilized fluidized bed has the appearance of an expanded fixed bed with no gross solids circulation and very little or no gas bypassing.

Claims

1. [.26. The process of claim 25 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 25% over the region of a portion of the fluidized bed containing the particulate magnetizable, fluidizable material..]. .[.27. The process of claim 25 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 10% over the region of a portion of the fluidized bed containing the particulate magnetizable, fluidizable material..]. .[.28. The process of claim 25 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 a portion of the fluidized bed containing the particulate magnetizable, fluidizable material..]. .[.29. A fluidized bed process, which comprises stably fluidizing at least a portion of a bed comprised of solid particulate magnetizable, fluidizable composite particles which contain 2-40 volume percent of ferro- or ferrimagnetic material located within an external force field containing said composite materials to a nontime varying and substantially uniform applied magnetic field having a substantial component along the direction of the external force field such that said composite particles have a component of magnetization M along the direction of the external force field of at least 100 gauss by passing a gas opposing said external force field at a superficial fluid velocity ranging between:

(a) more than the normal minimum fluidization superficial fluid velocity required to fluidize said bed in the absence of said applied magnetic field; and

,

(b) less than the superficial fluid velocity required to cause time-varying fluctuations of pressure difference through said stably fluidized bed portion over a 0.1 to 1 second interval during continuous fluidization in the presence of said applied magnetic field..]. .[.30. The process of claim 29 wherein said fluidized bed is subjected to an applied magnetic field ranging between 150 to 400 oersteds oriented axially to the flow of gas in the stably fluidized bed zone..]. .[.31. The process of claim 29 wherein said fluidizing gas has a superficial velocity in the range of 2 to 10 times the normal minimum superficial gas velocity required to fluidize the bed in the absence of an applied magnetic field..]. .[.32. The process of 29 wherein the magnetizable, fluidizable composite particles contain catalytic nonmagnetic material..]. .[.33. The process of claim 29 wherein the magnetizable, fluidizable composite particles contain a zeolitic crystalline aluminosilicate and a ferromagnetic material..]. .[.34. The process of claim 29 wherein the magnetizable, fluidizable composite particles contain 5 to 20 volume percent ferro- or ferrimagnetic material and the balance is nonmagnetic material..]. .Iadd. 35. A process for controllably transporting a flowable bed containing magnetizable particles within a vessel, said bed being expanded and levitated within said vessel by a fluid stream, 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, said process comprising the steps;

(a) subjecting at least a portion of said bed to an applied magnetic field having a substantial component along the direction of a force field external to said bed; and

(b) controllably transporting said bed within said vessel in response to a pressure differential in said bed. .Iaddend. .Iadd. 36. The process of claim 35 wherein said external force field is gravity. .Iaddend..Iadd. 37. The process of claim 35 wherein said fluid is gaseous. .Iaddend..Iadd. 38. The process of claim 35 wherein said bed additionally contains nonmagnetizable particles. .Iaddend..Iadd. 39. The process of claim 35 wherein said magnetizable particles are comprised of composite particles which include magnetizable and nonmagnetizable material. .Iaddend..Iadd. 40. The process of claim 39 wherein said composite particles include a zeolitic material. .Iaddend..Iadd. 41. The process of claims 35, 36, 37, 38, 39 or 40 wherein said applied magnetic field is nontime-varying and substantially uniform. .Iaddend..Iadd. 42. The process of claims 35, 36, 37, 38, 39 or 40 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. 43. The process of claim 35 wherein the flow of fluid is not substantially more than about 98% of the superficial fluid velocity required to cause a 0.1% ratio of root-mean square fluctuation of pressure difference to mean-pressure difference through the expanded bed in the presence of said applied magnetic field. .Iaddend..Iadd. 44. The process of claim 35 wherein the uniformity of said applied magnetic field is such that the ratio of local intensity of the applied magnetic field to the mean field varies by not more than 25% over the region of the bed containing the magnetizable particles. .Iaddend..Iadd. 45. The process of the claim 35 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 10% over the region of the bed containing magnetizable particles. .Iaddend. .Iadd. 46. The process of claim 35 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. 47. The process of claim 35 wherein said bed medium is transported in a plug-flow manner. .Iaddend..Iadd. 48. The process of claim 35 wherein said bed medium is transported from one vessel to another vessel. .Iaddend..Iadd. 49. A process for controllably transporting a flowable bed containing magnetizable particles within a vessel, said bed being expanded and levitated within said vessel by a fluid stream, said process comprising the steps;

(a) subjecting at least a portion of said bed to an applied magnetic field having a substantial component along the direction of gravity of at least 10 gauss within said bed; and

(b) controllably transporting said bed in response to a pressure differential in said bed within said vessel, wherein the superficial fluid velocity of said fluid stream ranges between;

(1) at least about 10% greater 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

2. presence of said applied magnetic field. .Iaddend..Iadd. 50. The process of claim 49 wherein the flow of fluid is not substantially more than about 98% of the superficial fluid velocity required to cause a 0.1% ratio of root-mean square fluctuation of pressure difference to mean-pressure difference through the expanded bed in the presence of said applied magnetic field. .Iaddend..Iadd. 51. The process of claim 49 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 not more than 25% over the region of the bed containing the magnetizable particles. .Iaddend..Iadd. 52. The process of claim 49 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 10% over the region of the bed containing magnetizable particles. .Iaddend..Iadd. 53. The process of claim 49 wherein the uniformity of said applied magnetic field is such that the ratio of the local intensity of the applied magnetic field varies by no more than 5% over the region of the bed containing magnetizable particles. .Iaddend..Iadd. 54. The process of claim 49 wherein said bed medium is transported in a plug-flow manner within said vessel. .Iaddend. .Iadd. 55. The process of claim 54 wherein said bed medium is transported from one vessel to another vessel. .Iaddend..Iadd. 56. The process of claim 49 wherein said applied magnetic field is nontime-varying and substantially uniform. .Iaddend..Iadd. 57. The process of claim 49 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. 58. The process of claim 49 wherein said fluid is gaseous. .Iaddend..Iadd. 59. The process of claim 49 wherein said bed additionally contains nonmagnetizable particles. .Iaddend..Iadd. 60. The process of claim 49 wherein said magnetizable particles are comprised of composite particles which include magnetizable and nonmagnetizable material. .Iaddend..Iadd. 61. The process of claim 60 wherein said composite particles include a zeolitic material. .Iaddend..Iadd. 62. The process of claims 35, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 or 61 wherein an ab- or adsorptive separation is taking place in said bed. .Iaddend..Iadd. 63. A process of controllably transporting a flowable bed containing magnetizable composite particles within a vessel said particles contain 2-40 volume percent of ferro- or ferrimagnetic material and the balance nonmagnetic material, said bed being expanded and levitated within said vessel by a fluid stream, said process comprising the steps:

(a) subjecting at least a portion of said bed to a substantially uniform magnetic field having a substantial component along the direction of gravity said that said composite particles have a component of magnetization M along the direction of the external force field of at least 100 gauss; and

(b) controllably transporting said bed within said vessel in response to a pressure differential in said bed, wherein the superficial fluid velocity of said fluid stream ranges between;

(1) more than the normal minimum 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 bed over a 0.1 to 1 second interval during continuous operation in the presence of said

3. applied magnetic field. .Iaddend..Iadd. 64. The process of claim 63 wherein said bed medium is transported in a plug-flow manner. .Iaddend..Iadd. 65. The process of claim 63 wherein said bed medium is transported from one vessel to another vessel. .Iaddend..Iadd. 66. The process of claim 63 wherein said applied magnetic field is nontime-varying. .Iaddend..Iadd. 67. The process of claim 63 wherein said applied magnetic field is time-varying and said magnetizable material has a zero or relatively low coercivity. .Iaddend..Iadd. 68. The process of claim 63 wherein said applied magnetic field ranges between 150 and 400 oersteds oriented axially to the flow of the fluid. .Iaddend..Iadd. 69. The process of claim 63 wherein said composite particle include a zeolitic crystalline aluminosilicate and a ferromagnetic material and an ab- or adsorptive separation is taking place in said bed. .Iaddend. .Iadd. 70. The process of claim 69 wherein said fluid is liquid. .Iaddend..Iadd. 71. The process of claim 69 wherein said fluid is gaseous. .Iaddend. .Iadd. 72. The process of claims 35, 49, or 63 wherein a catalytic cracking reaction is taking place in said bed. .Iaddend..Iadd. 73. The process of claims 35, 49 or 63 wherein a fluid hydroforming process is taking place in said bed. .Iaddend..Iadd. 74. The process of claims 35, 49 or 63 wherein an alkylation process is taking place in said bed. .Iaddend..Iadd. 75. The process of claims 35, 49 or 63 wherein a partial oxidation process is taking place in said bed. .Iaddend..Iadd. 76. The process of claims 35, 49 or 63 wherein a chlorination process is taking place in said bed. .Iaddend..Iadd. 77. The process of claims 35, 49 or 63 wherein a dehydrogenation process is taking place in said bed. .Iaddend..Iadd. 78. The process of claims 35, 49 or 63 wherein a desulfurization or reduction is taking place in said bed. .Iaddend..Iadd. 79. The process of claims 35, 49 or 63 wherein the gasification of coal is taking place in said bed. .Iaddend..Iadd. 80. The process of claims 35, 49 or 63 wherein the fluid bed combustion of coal is taking place in said bed. .Iaddend..Iadd. 81. The process of claims 35, 49 or 63 wherein the retorting of oil shale is taking place in said bed. .Iaddend.