After the initial delivery by NEM Power-Systems of fifteen diverter dampers to Qurayyah, the client decided additional upgrades are needed. Apart from the usual equipment such as guillotines and hoists, additional air injection was required by Doosan.
One of the particularities of the additional components will be the introduction of seal air to the guillotine damper. Since the original dampers already were supplied by NPS in a former project, the existing guillotine damper casings were not designed to receive the seal air in addition to the diverter dampers. This challenge has now been dealt with by designing the new guillotine blades for the expected seal air pressure, sealing the chamber between both closed blades (diverter and guillotine) and injecting seal air in between. This "double seal air method" shall provide additional safety for maintenance personnel while accessing the HRSG.
Since it is planned to have a maximum of three HRSG on outage simultaneously, the number of redundant seal air fan skids for the guillotines is limited to three. Such skids are designed in such manner that they can be transported to the individual unit by means of a fork lift.
Scope of Supply
15 units 'upgrade parts' for diverter/guillotine damper system behind GE frame 7FA gas turbine
Client: Doosan Heavy Industries
End user: Saudi Electric Company (SEC)
Type of plant: Combined Cycle Thermal Power Plant
Location: Qurayyah, Saudi Arabia
- Duct size: 5640 x 5640 mm
- Temperature: Up to 640 °C operation, 663°C design
- Pressure: Up to 78 mbar
- Hydraulic (diverter)
- Electric (guillotine)
- Exterior: Carbon steel
- Interior: Stainless steel Alloy 800H