Abstract: Disclosed is a method, a system and an improved butterfly valve usable therein for recovering energy from a continuous supply of hot pressurized particulate-laden flue gas. This gas is conducted to the atmosphere via a selected one of a plurality of ducts equipped with separate purgable butterfly cut-off valves each located upstream both from the point of gas disposal to the atmosphere and from separate energy recovery devices. Each duct has provision downstream from an associated cut-off valve for insertion of a slip blind crosswise of that duct after closure of the cut-off valve thereby permitting servicing operations on the energy recovery device deactivated by the closed valve or valves. One or more of the recovery devices is usable to supply operating power for components of the system or to other equipment.

Abstract: A butterfly valve is disclosed for use in controlling the flow of gaseous fluid under high temperature, high pressure conditions. The interior of the valve body has non-overlapping semi circular valve seats spaced to either side of the shaft for the valve disc. The valve disc is rigid and inflexible throughout and, when closed, its periphery terminates close to the interior of the valve body under all operating temperatures. When the disc is closed, the semi-circular valve seats cooperate with the recessed rigid periphery of the disc to form a chamber chargeable with purging fluid at a higher pressure than the fluid on the upstream side of the valve and effective to prevent flow of the latter past the valve disc.

Abstract: A power recovery separator for processing huge volumes of high temperature pressurized dirty gas en route to a high temperature gas expander. The separator has a single housing sub-divided into overhead, inlet and underflow chambers by a pair of flanged and dished heads of erosion and heat resistant material having a higher coefficient of expansion than the housing material. A multiplicity of inertial separators are supported in parallel between the dished heads and secured to only one thereof. At least portions of the head flanges bear radially against the interior of the housing sidewalls and their rim edges are welded to the housing and, in consequence, expansion of the head serves, in part, to augment the bulge and, in part, to place the high strength housing wall in hoop tension without subjecting the welding to rupture stresses.