Abstract: A power plant is disclosed in which a steam turbine/coal-fired steam boiler is integrated with an air turbine via using the convection section of the boiler to heat compressed air for the turbine, by indirect heat exchange with the flue gas, the hot turbine exhaust being sent to the boiler as preheated combustion air. In this way, only clean air reaches the turbine and not combustion products which would result from direct firing of fuel in compressed air, whereby coal may be burned instead of premium quality fuels. Platens in the radiant section of the boiler are used both to regulate flue gas temperature and take over some of the usual convection section services to release it for compressed air heating service.

Abstract: A trough-type scale trap for use with a refinery or chemical plant reactor having a catalyst bed subject to plugging by fine particles. Compared to prior art traps, the trough-type scale trap of the invention is characterized by a larger volumetric capacity and screen area and is substantially easier to construct and to install or remove from closed reactor vessels than conventional traps. Its typical embodiment is as a series of parallel troughs having rectangular openings and disposed chordally across the reactor normal to the direction of flow. In one embodiment, the trough is a rectangular parallelepiped; in another embodiment, the substantially rectangular opening is reduced by tapering to a bottom significantly smaller than the inlet opening.