Abstract: A new and improved heat recovery steam generating apparatus for extracting heat from a hot gas stream, comprises a vertically extending tube bank having upper and lower headers at opposite ends. Two pairs of external, gravity force, support columns are spaced upstream and downstream of the tube bank and a top support structure is mounted at the upper end of the columns for supporting the tube bank in downwardly hanging relation from the upper header. A pair of permanent internal trusses are supportively connected at the upper end to the columns and each truss has opposite edges slidably supported from a pair of columns for accommodating expansion and contraction of the tubes and for transferring and resisting lateral and shear loads, which loads are eventually transferred to a bottom structure at the lower end of the columns.

Abstract: A modular wall liner panel for use in a duct system for containing a flow of gases comprises a central wall segment having a polygonal shape forming an inside wall surface of the, duct and having angularly intersecting pairs of parallel edges. Integral mounting edge flanges are provided adjacent the respective edge of the central wall segment adapted to be detachably securable in place on a supporting grid structure of the duct system wall structure. The grid structure has a plurality of elongated first and second parallel support elements extending transversely to one another and fasteners are provided for detachably securing at least one pair of mounting edge flanges of each duct liner panel to a pair of adjacent parallel support elements of the grid structure.