Multiple cooled supports for heat exchange tubes in heat exchanger

A once-through, duct-fired heat recovery steam generator (HRSG) of a combined cycle power plant, the once-through duct-fired HRSG comprising:

• a casing configured to direct a working fluid therethrough;
• and
• a plurality of laterally adjacent heat exchanger (HE) sections configured to span a substantial portion of the working fluid path, each HE section including a pair of spaced supports, each spaced support including:
• an upstream support and a downstream support, wherein at least one of the upstream support and the downstream support includes a coolant carrying body configured to direct a coolant therethrough;
• a first cross-support coupled to and extending between respective upstream and downstream supports;
• at least one second cross-support coupled to and extending between the respective upstream and downstream supports, each second cross-support of the at least one second cross-support vertically distanced from an adjacent cross-support thereabove;
• and
• a plurality of tube positioners suspended from each cross-support, each tube positioner positioning a plurality of heat exchange tubes extending across at least a portion of a working fluid path through the casing;
• wherein each tube positioner positions a plurality of heat exchange tubes in a vertical plane;
• and
• wherein each pair of spaced supports, the cross-supports, and the plurality of tube positioners are made of a ferritic material,
• wherein the at least one second cross-support comprises a plurality of second cross-supports, wherein each second cross-support of the plurality of second cross-supports has an upstream end coupled to the upstream support and a downstream end coupled to the downstream support, wherein the upstream end is vertically higher than the downstream end, creating an attack angle with the working fluid path for the respective second cross-support.