Patent GB-796914-A (GB)
Title: Contacting solids with gaseous fluids
Inventor: ROETHELI BRUNO EMIL
IPC: B01J8/38
Filed: 1956-08-17
Abstract: <PICT:0796914/IV (b)/1> In a process for contacting a gaseous fluid with a finely divided solid, e.g. the catalytic dehydrogenation of alkanes to alkadienes, a vertical column of the solids M10, fluidized by a gas passed through pipe 36, is maintained in a feed zone 10 from which the solids pass through openings 14 into the bottom 30 of a contacting zone 26 surrounding the feed zone, the gas is introduced by pipe 22 and the solids-gas mixture is passed upwards, the dimensions of the upper 28 and lower 26 portions of the contacting zone being such that the linear velocity of the gas and solids is greater in the upper than the lower portion, and discharged in a swirling motion into a free space 34 above the column of solids whereby the solids separate and collect on the column and the treated gas is withdrawn by pipe 20.  The solids density in the lower contacting zone is preferably 6-30 lbs./cu. ft. and the linear velocity of the gas 0.5-50 ft./sec.  The oblong openings 14 in the conical bottom 12 of the feed zone may be adjustable.  The swirling motion of the gases entering the space 34 is induced by vanes 32 in the form of flat or curved plates at an angle to the flow of gas and close to the wall of the outer jacket 16.  The width of the lower part of the contacting zone 26 is 2-10 times that of the upper portion 28 and about equal in length, the conical portion 30 being about half that length, and the diameter of the outlet pipe 20 is 1/8 -\ba2/3 the diameter of the feed zone 10.  The feed zone may have a solids withdrawal line 38 by which solid may be withdrawn to be regenerated, being returned with the gas by pipe 22.  A grid 24 may be disposed above the gas inlet.  In dehydrogenating butenes to butadiene, a chromia-alumina catalyst of particle size 100-400 U.S. mesh is maintained at a density of 30 lbs./cu. ft. by feeding 15-20 lbs. of catalyst per cu. ft. of gas which flows through the lower contacting zone at about 20 ft./sec. and the upper zone at not less than 50 ft./sec., the contacting time being 0.1-2 seconds.  The thermal cracking of hydrocarbons to give acetylenes is also referred to.ALSO:<PICT:0796914/III/1> In a process for contacting a gaeous fluid with a finely divided solid, a vertical column of the solids M10, fluidized by by a gas passed through pipe 36, is maintained in a feed zone 10 from which the solids pass downwardly through openings 14 into the bottom 30 of a contacting zone 26 surrounding the feed zone.  The gas is introduced by pipe 22 and entrains the solid and the solid-gas mixture is passed upwards, the dimensions of the upper 28 and lower 26 portions of the contacting zone being such that the linear velocity of the gas and solid is greater in the upper than the lower portion, and is discharged in a swirling motion into a free space 34 above the column of solid, whereby the solid separates and collects on the column and the treated gas is withdrawn by pipe 20. The solid density in the lower contacting zone is preferably 6-30 lb./cu. ft., and the linear velocity of the gas 0.5-50 ft./sec.  The oblong openings 14 in the conical bottom 12 of the feed zone may be adjustable.  The swirling motion of the gases entering space 34 is induced by vanes 32 in the form of flat or curved plates disposed at an angle to the gas flow and close to the wall of the outer jacket 16.  The width of the lower part of the contacting zone 26 is 2-10 times that of the upper portion 28 and about equal in length, the conical portion 30 being about half that length, and the diameter of the outlet pipe 20 is 1/8 -\ba2/3 the diameter of the feed zone 10. The feed zone may have a solid withdrawal line 38 by which solid may be withdrawn to be regenerated being returned with the gas by pipe 22.  A grid 24 may be disposed above the gas inlet.  The catalytic dehydrogenation of hydrocarbons is described, using chromia and aluminia as catalyst (see Group IV (b)) and the cracking of hydrocarbons to give acetylenes and the demethanation of ketones are also referred to.