Abstract: A solids-laden gas is cleaned by introducing a condensing fluid in the gas to saturate the gas and allowing liquid to condense on the solids to form enlarged particles. Liquid separated from the gas with enlarged particles is then atomized in the gas to form agglomerates of liquid and enlarged particles, whereafter the formed agglomerates are separated from the gas. An apparatus for carrying out this process is also described, the apparatus being characterized by a first stage in which means are provided for enlarging solids in a solids-laden gas flow by contact with a condensing fluid, separation of liquid from the gas flow, and a second stage in which means are provided for introducing the separated liquid into the gas flow in a venturi-shaped gas passage member.

Abstract: The walls of a heat exchanger for cooling a particle-contaminated gas are continuously cleaned by adding cleaning particles to the gas, separating the cleaning particles, and collecting the separated cleaning particles into a fluidized bed providing sufficient hydrostatic pressure to displace cleaning particles into the heat exchanger.

Abstract: An apparatus for separating a carrier gas from a particle stream is disclosed which comprises deflecting said particle stream about a curved surface to compact the stream and separate therefrom a major proportion of said carrier gas, and introducing a substitute fluid into said compacted stream via at least one aperture in said curved surface to displace substantially the remainder of the carrier gas from the spaces between the particles. The invention is usefully applied for rapid disengagement of gases from a particulate stream, particularly in the catalytic cracking of hydrocarbons.