Hinged baffle assemblies for heat recovery steam generators (HRSGs) are disclosed. The baffle assemblies may include a baffle plate for directing exhaust fluid through a casing of the HRSG. The baffle plate may include first and second ends, a first surface exposed to the exhaust fluid flowing through the casing, and a second surface opposite the first surface. The baffle assemblies may also include a hinge component coupled to the first end of the baffle plate and positioned within/fixed relative to the casing. Additionally, the baffle assemblies may include a first diverter plate positioned adjacent to the second end of the baffle plate. The first diverter plate may directly contact the first surface of the baffle plate and may aid in directing the exhaust fluid through the casing of the HRSG.

A method for installing a heat recovery steam generator (1) with a plurality of pre-assembled modules (10) includes arranging a pre-assembled module (10) at an installation site. The pre-assembled module (10) includes a functional unit of the heat recovery steam generator (1) housed in a casing structure (12). The casing structure (12) includes a top casing (12a), a bottom casing (12b) and a side casing (12c). An open side (15) is defined opposite to the side casing (12c). The module (10) is arranged horizontally at the installation site with the open side (15) facing downward and the side casing (12c) facing upward. The method includes attaching a structural steel (13) to the side casing (12c) in a horizontal position without lifting the module (10). The module (10) with the attached structural steel (13) is lifted to a vertical position and secured to a foundation (60). Also described is a method for pre-assembling the module (10) and a method for transporting the pre-assembled module (10) to the installation site.

Disclosed herein is a once-through evaporator comprising an inlet manifold; one or more inlet headers in fluid communication with the inlet manifold; one or more tube stacks, where each tube stack comprises one or more inclined evaporator tubes; the one or more tube stacks being in fluid communication with the one or more inlet headers; where the inclined tubes are inclined at an angle of less than 90 degrees or greater than 90 degrees to a vertical; one or more outlet headers in fluid communication with one or more tube stacks; and an outlet manifold in fluid communication with the one or more outlet headers; and a baffle system comprising a plurality of baffles; the baffle system being disposed adjacent to a tube stack so that the baffle system contacts a tube.

Disclosed herein is a once-through evaporator comprising an inlet manifold; one or more inlet headers in fluid communication with the inlet manifold; one or more tube stacks, where each tube stack comprises one or more substantially horizontal evaporator tubes; the one or more tube stacks being in fluid communication with the one or more inlet headers; one or more outlet headers in fluid communication with one or more tube stacks; and an outlet manifold in fluid communication with the one or more outlet headers.

The method for erecting a boiler includes erecting a main structure, providing preassembled modules defining a boiler section, installing the modules outside the main structure.

A method for installing a heat recovery steam generator (1) with a plurality of pre-assembled modules (10) includes arranging a pre-assembled module (10) at an installation site. The pre-assembled module (10) includes a functional unit of the heat recovery steam generator (1) housed in a casing structure (12). The casing structure (12) includes a top casing (12a), a bottom casing (12b) and a side casing (12c). An open side (15) is defined opposite to the side casing (12c). The module (10) is arranged horizontally at the installation site with the open side (15) facing downward and the side casing (12c) facing upward. The method includes attaching a structural steel (13) to the side casing (12c) in a horizontal position without lifting the module (10). The module (10) with the attached structural steel (13) is lifted to a vertical position and secured to a foundation (60). Also described is a method for pre-assembling the module (10) and a method for transporting the pre-assembled module (10) to the installation site.

A heat recovery steam generator (HRSG) includes a base and a top platform assembly disposed on the base. The top platform assembly includes a first top platform auxiliary module having a first rectangular frame in which a steam manifold is disposed, a second top platform auxiliary module having a second rectangular frame in which a high pressure (HP) drum is disposed, and a third top platform auxiliary module having a third rectangular frame in which a low pressure (LP) drum and an intermediate pressure (IP) drum are disposed. Each top platform auxiliary module may be pre-assembled on the ground prior to be raised to elevation for installed on the base.