Appendix E-2.c.i Energy Plan 2004-2013 Follow-up Studies and ...

Re-powering Study for the Northport and Port Jefferson Power Stations
Appendix II Northport System Descriptions
turbine exhaust hood spray, and condenser curtain spray, as well as water for HRSG IP and HP drum fill
and closed cooling water system make-up. The Condensate System is capable of continuous operation for
flow rates ranging from minimum recirculation to 100 percent of design capacity.
Each pump suction line contains a butterfly isolation valve, a basket strainer, a relief valve and an
expansion joint at the pump suction connection. The basket strainer is supplied with a coarse mesh
element for normal plant operation and a fine mesh element for flushing and start-up. Pressure differential
indication is provided for each strainer in the distributed control system (DCS).
Each pump discharge line contains a local pressure gage, check valve, butterfly isolation valve, and slipstream
for pump seal water. Each pump is vented by individual lines to the condenser.
A recirculation valve provides condensate pump minimum flow protection and maintains the required
minimum flow through the gland steam condenser. Recirculation water is returned to the condenser
hotwell. The recirculation line is designed for single pump operation. Therefore, the duration of twopump
operation should be limited when in the minimum recirculation mode.
The hotwell level is controlled by make-up and draw-off. Hotwell make-up is provided by normal
make-up and the high-capacity make-up control valves which control condensate flow into individual
condenser connections in response to hotwell low level. The normal make-up control valve directs
condensate into the condenser above the tube bundle to allow it to be deaerated. The high-capacity
make-up control valve directs condensate directly into the hotwell to ensure the condensate pump suction
source.
In response to high hotwell level, the draw-off control valve directs condensate pump discharge to the
circulating water piping.
A sampling connection is provided on the condensate pump discharge to monitor water chemistry.
Chemicals controlling pH and oxygen are injected into the condensate discharge piping upstream of the
air ejectors and gland steam condenser to maintain water chemistry.
The control system is designed to automatically start the standby pump when the condensate header
pressure becomes low. The condensate pump(s) will automatically trip if the condenser hot well level
drops below a minimum acceptable level.
1.7 Feedwater
Refer toPID-06-1A and PID-06-01B in Appendix III.
For The Hybrid Option, the feedwater system has two feedwater pumps for each HRSG. The two 100%
capacity, segmental ring feedwater pumps are each fitted with an adjustable speed fluid coupling and
driven by a constant speed motor. The pumps take suction from the LP drum of the related HRSG. The
pump discharge feeds the relevant HRSG’s HP system. Each pump has an interstage bleed that feeds the
relevant IP system. The pump suction lines each contain a manual gate valve, pressure and temperature
instrumentation, and a duplex basket strainer with a differential pressure transmitter to provide indication
and a high alarm on the distributed control system (DCS).
1.7.1 High Pressure Feedwater
The feedwater pump HP discharge line is provided with an automatic recirculation (ARC) valve and a
manual gate valve. The ARC valve automatically maintains the required minimum flow through the pump
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