Inlet duct system for a heat recovery steam generator

A system, comprising:

• a gas turbine system;
• a heat recovery steam generator (HRSG);
• and
• an exhaust diffuser system, comprising:
• an inlet portion coupled to the gas turbine system;
• a diffuser portion axially extending from the inlet portion, wherein the diffuser portion comprises a plurality of sides arranged about a central axis of the diffuser portion;
• and
• a plenum fluidly coupled to an axial distal end of the diffuser portion, wherein the plenum is coupled to the HRSG;
• wherein a plenum extent of the plenum is greater than an inlet extent of the inlet portion, at least one side of the plurality of sides of the diffuser portion comprises a plurality of wall portions, the plurality of wall portions is incrementally angled relative to an axial extent extending from the inlet portion to the plenum, the plenum comprises a curved wall extending crosswise to the axial extent, and the plurality of wall portions comprises four or more wall portions;
• wherein each wall portion of the plurality of wall portions is angled relative to an immediately preceding wall portion of the plurality of wall portions by an angle within a common angular range of angles between 150 degrees and 179 degrees, or angles between successive wall portions of the plurality of wall portions change by less than 10 degrees, or a combination thereof.

A method, comprising:

• receiving an exhaust flow from a gas turbine via an inlet portion of an exhaust diffuser system;
• expanding the exhaust flow in a diffuser portion of the exhaust diffuser system, wherein the diffuser portion comprises a plurality of sides arranged about a central axis of the diffuser portion, at least one side of the plurality of sides of the diffuser portion comprises a plurality of wall portions incrementally angled from the inlet portion toward an outlet portion of the exhaust diffuser system, wherein the plurality of wall portions comprises four or more wall portions;
• and
• discharging the exhaust flow into a heat recovery steam generator (HRSG) via a plenum of the outlet portion, wherein the plenum comprises a curved wall extending crosswise to the diffuser portion;
• wherein each wall portion of the plurality of wall portions is angled relative to an immediately preceding wall portion of the plurality of wall portions by an angle within a common angular range of angles between 150 degrees and 179 degrees, or angles between successive wall portions of the plurality of wall portions change by less than 10 degrees, or a combination thereof.

A system, comprising:

• a gas turbine system;
• a heat recovery steam generator (HRSG);
• and
• an exhaust diffuser system, comprising:
• an inlet portion coupled to the gas turbine system;
• a diffuser portion axially extending from the inlet portion;
• and
• a plenum fluidly coupled to an axial distal end of the diffuser portion, wherein the plenum is coupled to the HRSG;
• wherein a plenum extent of the plenum is greater than an inlet extent of the inlet portion, the diffuser portion comprises a plurality of wall portions, the plurality of wall portions is incrementally angled relative to an axial extent extending from the inlet portion to the plenum, the plenum comprises a curved wall extending crosswise to the axial extent, and the diffuser portion is coupled to a convex side of the curved wall of the plenum.

A system, comprising:

• an exhaust diffuser system for a heat recovery steam generator (HRSG), comprising:
• an inlet portion;
• a diffuser portion axially extending from the inlet portion;
• and
• an outlet portion fluidly coupled to an axial distal end of the diffuser portion;
• wherein an outlet extent of the outlet portion is greater than an inlet extent of the inlet portion, the diffuser portion comprises a plurality of wall portions, the plurality of wall portions is incrementally angled relative to an axial extent extending from the inlet portion to the outlet portion, the diffuser portion comprises an annular surface configured to interface with the inlet portion, an outer boundary of the annular surface is octagonal in shape, and the plurality of wall portions comprises four or more wall portions.