GB607723A - Improvements in and relating to the handling of particulate materials - Google Patents

Abstract

607,723. Pneumatic conveyers. ARNOLD, M. H. M., YOUNG, R. J., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. Jan. 18, 1946, Nos. 1769 and 35881. [Class 78 (i)] A bed 2, Figs. 2 and 4, of particulate solid material is maintained from a column 4 terminating at its surface and is fed, as required into a vessel 1 by pass ing gas through it at a suitable velocity, e.g by way of a perforated or porous support 6. As the gas velocity is increased up to a critical value at which the material becomes fluid, its angle of repose is progressively reduced to zero, and the material consequently flows into the vessel 1 at an increasing rate. At velocities above the critical value the discharge rate remains constant, until ultimately the material becomes entrained in the gas stream. A preliminary calibration with a particular apparatus and material consequently enables varying discharge rates to be obtained by applying the appropriate gas velocities. In Fig. 2, the column 4 is confined by a tube 5 terminating at the level of the undisturbed bed, which is disposed in a side chamber communicating with the vessel 1 and confined by a weir 9. Alternatively, the bed may be located in the vessel 1 and surrounded by a weir. By terminating the tube 5 substantially at the level of the weir, discharge only occurs when the gas velocity is sufficient to render the material fluid (zero angle of repose), and the discharge rate is constant. In Fig. 4, a bed 8 of material is maintained at a fixed level 11 in the vessel 1 by a pipeline 10 connected directly with the bed 2 and column 4. A second material is supplied by a pipeline 12, and is mixed with material from the bed 2 by applying gas to the bed through a connection 7. In Fig. 1 (Comp.), the bed is located in a passage 17 between the vessel 13 to be filled and the supply column 15. The floor of the passage has a recess 18 containing fragments of refractory material of decreasing particle size upwards, and through which gas is passed from a pipeline 19 to discharge material from the bed. The material is maintained at a fixed level 20 in the vessel 13 by a direct connection from the column 15. The invention is applicable where reaction is required between a particulate solid and a gas or vapour, or between the components of a gaseous mixture and a catalyst. It is also applicable to the process of Specification 569,691, [Group III], in which coke-oven gas is passed through a bed of active carbon, maintained as a fluid bed, for the recovery of ethylene. Specification 596,258, [Group III], also is referred to.