Umm Al Houl Power (UHP) Independent Water and Power Facility
near Doha, Qatar
Owners: Qatar Electricity and Water Company (QEWC), Qatar Petroleum, Qatar Foundation, and Mitsubishi Corporation
The Umm Al Houl Power (UHP) Independent Water and Power Facility under construction near Doha, Qatar includes a 2520-MW combined-cycle cogeneration plant and will produce 136.5 million imperial gallons of potable water per day. Approximately 55% of the potable water will be produced using Multi-Stage Flash (MSF) technology with the remainder produced using Reverse Osmosis (RO) technology.
The power portion of the project comprises two combined-cycle power blocks where each block includes three Siemens SGT5-4000 gas turbine generators; three heat recovery steam generators (HRSGs) with bypass stacks and duct burning; and two Siemens SST5-4000 condensing steam turbine generators (STGs) with controlled low-pressure steam extractions. Both power blocks send low-pressure steam to a common header supplying the five MSF modules.
The selected plant configuration lends itself to a wide range of operating conditions, with the capability of producing power and water nearly independent of each other. This is a rather complex control scheme that presents many challenges, including:
- Reliably controlling steam supply to the MSFs during transient conditions.
- Starting a cold steam turbine in a 3×2 configuration without affecting other operations.
- Controlling the flow of condensate from four STG condensers and five MSFs, all supplying a common header while also controlling makeup water to the system.
- Operating the proper number of gas and steam turbines to efficiently meet power and water demands.
- Controlling the steam turbine operating range to achieve proper extraction steam conditions.
- Starting up the plant using a steam bypass system that can dump to multiple steam turbine condensers.
This paper explores the challenges in controlling these plant operating parameters and illustrates the approach taken to implementing plant controls.
David Rice and Steve Wylie – Sargent & Lundy
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