Tender Document for Construction of Ghorasal 300-450 MW ... - BPDB
Tender Document for Construction of Ghorasal 300-450 MW ... - BPDB
Tender Document for Construction of Ghorasal 300-450 MW ... - BPDB
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
heat recovery steam generator shall be measured by a flow nozzle and flow<br />
proportional signals shall be transmitted to the control panel.<br />
In addition, super heater outlet shall be fitted with a steam sampling connection<br />
as well as an acid cleaning connection, each feeder also shall have<br />
manual free blow <strong>for</strong> maintenance purposes.<br />
A motor operated relief valve shall be provided in the common main steam<br />
header. A control switch <strong>for</strong> remote operation <strong>of</strong> this relief valve shall be<br />
provided in the control room.<br />
The main steam header shall deliver steam to the steam turbine stop valve,<br />
bypass system, steam seal/gland regulator, and condenser ejector system.<br />
As a part <strong>of</strong> the main steam system, a turbine bypass shall be provided.<br />
The bypass system shall be placed in operation at start-up when the motor<br />
operated shut <strong>of</strong> valve is opened. Bypass line shall be fitted with relief<br />
valves <strong>for</strong> overpressure protection.<br />
3.3.3 Feed water System<br />
Steam generator feed water shall be supplied with condensate from a surface<br />
condenser, deaerated in the Deaerator. Suitable chemicals will be<br />
added in the feed water cycle <strong>for</strong> oxygen scavenging and Ph control.<br />
Deminarelized water will be used as make up to the plant.<br />
The boiler feed water pump <strong>of</strong> steam turbine generating plant shall be<br />
composed <strong>of</strong> Three (3) x 60% duty motor driven pumps.<br />
Each pump shall be horizontal, multi-stage, centrifugal type capable <strong>of</strong><br />
supplying two times <strong>of</strong> heat recovery steam generator MCR flow plus a<br />
margin to cover boiler swing and eventual reduction in effective capacity<br />
from water. Provision shall be made <strong>for</strong> standby pump to run automatically<br />
on failure <strong>of</strong> the running pump. The rated pressure <strong>of</strong> the feed pump should<br />
be derived from the system resistance <strong>of</strong> the feed system at rated feed<br />
flow. This system resistance shall include a static portion, incorporating the<br />
drum design pressure, the pressure drop through the feed regulating valve<br />
and the height <strong>of</strong> the economizer.<br />
Each boiler feed pump shall be equipped with a minimum flow re-circulation<br />
system, consisting <strong>of</strong> a flow orifice, differential pressure transmitters and<br />
control valves. Recirculation water shall be returned to the Deaerator.<br />
Each feed water supply line to the respective heat recovery steam generator<br />
shall be fitted with a flow nozzle and its differential pressure transmitter<br />
which alone with the feed water regulator <strong>for</strong>m a part <strong>of</strong> the heat recovery<br />
steam generator drum level controls. A motorised shut-<strong>of</strong>f valve shall be<br />
provided ahead <strong>of</strong> the feed water regulator as well as motorised bypass<br />
valve.<br />
In the main header, a pressure transmitter shall indicate header pressure<br />
while a pressure switch shall be used to automatically initiate operation <strong>of</strong> a<br />
standby pump.<br />
The feed water shall be circulated in each heat recovery steam generator<br />
<strong>Ghorasal</strong> <strong>300</strong>-<strong>450</strong> <strong>MW</strong> CCPP Project (Vol-2A <strong>of</strong> 2) 28
Change language