Abstract: A fiber bed element and process for removing aerosols from gas streams wherein a bed of fibers is packed to a desired packing density between two foraminous screens. A substantial portion of the fibers in the bed are positioned in a generally parallel arrangement such that the element can be mounted in an operative position with such substantial portion of the fibers extending in a generally vertical direction to enhance drainage of collected aerosols from the element to thereby allow-operation at even high bed velocities with reduced re-entrainment of collected liquid and thereby increase the total collection efficiency of the element. In the process, the bed element is mounted such that the parallel fibers extend in a generally vertical direction and the gas to be treated is passed through the bed at a predetermined velocity.

Abstract: A method and apparatus for removal of particulates from gas streams with high collection efficiency on even submicron particulates. The apparatus includes a grounded fiber bed of 50 to 1000 micron average diameter fibers packed to a bed voidage of at least 90%, an electrostatic or ionizing field means upstream of the fiber bed to place an electrical charge on the particulates, and irrigation means for the fiber bed, and optionally the grounded electrodes of the electrostatic means as well, to flush collected particulates from the fiber bed and optionally from the grounded electrodes. The method is suitable for separation of any particulates but is particularly advantageous for separation of insoluble solid particulates from gas streams at high bed velocities of from 6 to 15 or more feet per second (i.e., 1.8 to 4.6 or more meters per second). The preferred fiber bed is of 100 to 500 micron diameter, and advantageously 100 to 250 micron diameter, glass fibers.

Abstract: A fiber bed separator and method are provided for separating aerosols of 3 microns and less from gases. Two fiber beds in intimate contact with one another are used. The first fiber bed, in the direction of gas flow is of fibers of at least about 5 microns mean diameter packed to a bed voidage of from about 85 to 98%, the fiber diameter and bed voidage being selected such that at design bed velocity and aerosol loading the first bed is not flooded and the residual saturation of said first fiber bed against gas drag on the liquid collected is less than the residual saturation of said bed against gravity drainage of the liquid. The second fiber bed is packed to a bed voidage of from about 85 to 99% with fibers of equal or greater mean diameter than those in the first fiber bed such that the residual saturation of said second fiber bed against gas drag is greater than the residual saturation of the bed against gravity drainage.

Abstract: Provisions are taken to counter nitrogen oxide fumes produced in catalyst preparation involving metal nitrate decomposition, as by including urea or another scavenger, or by delaying calcining until used as catalyst in treating auto exhaust.