Abstract: An apparatus for removing acid gas and fly ash from hot flue gas includes a housing containing a perforated plate extending thereacross for holding a cool bed of particulate scrubbing material. First means are provided for passing the hot flue gas through the cool bed for capturing the fly ash and causing condensation and removal of the acid gas by formation of a crust of solid reaction product on the particles. After condensation and reaction ceases, agitation means remove the crust from the particles and a second means passes a gas through the bed to entrain and remove the crust from the housing. Water spray means or a third means for passing a cool gas through the bed are provided for cooling the bed to a temperature below the dew point of the flue gas.

Abstract: The present invention provides an apparatus for measuring the pressure drop which occurs between two sides of an orifice plate attached to a filter bag. The apparatus includes a chamber with an orifice plate at one end and a pair of tubular pressure taps located on either side of the orifice plate whereby one tap is located on the upstream side of the orifice plate and the other is located at the downstream side. Both taps have a particular location and configuration to avoid clogging whenever the bags are cleaned. The apparatus is used in a sequentially timed and controlled system for measuring and recording bag performance of many bags in a baghouse. The system is formed by attaching the above apparatus to a plurality of bags in a baghouse and connecting the pressure taps from each apparatus to a sequentially activated and controlled valve system which individually measures the pressure drop at each bag through the use of a single differential pressure-measuring device.

Abstract: A process and apparatus is described for removing acid gas and fly ash directly from hot flue gas without the necessity of pretreating the gas. In addition, valuable heat energy is conserved in this process. The process involves three stages of operation which, when operated in sequence, allows condensation to form on the scrubbing medium without any preconditioning step. The process is particularly useful for removing SO.sub.2 or SO.sub.3 from flue gas.

Abstract: An electrostatic precipitator having improved collection efficiency for suspended particles having either high or low electrical resistivities is provided. The precipitator utilizes porous collecting surfaces which permit passage of gas while retaining suspended particles and means are provided to create an electrostatic field causing the particles to migrate toward the collecting surfaces. According to the invention, only a portion of the inlet gas flow to the precipitator, sufficient to provide aerodynamic forces to facilitate adherence of the particles to the collecting surface, is drawn through the porous collecting surfaces with the remainder of the gas flow being essentially parallel to such surfaces. The two gas streams are separately withdrawn and may be combined to provide a clean gas effluent. The invention also provides an improved method for removing suspended particles from gases by electrical precipitation.