4"12-Z 1 - part - usaid

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mass flow meters must be installed for momtoring and controlling fuel input. Each boiler has
a 159 mm diameter 0-20 T/H mazut supply line and a 66 nun diameter 0-10 T/H mazut return
line.
Combustion Controls
Combustion control is remote manual from a central control room. Operators can adjust gas
control valve position, mazut control valve position or rotary vane coal feeder speed so that the
quantity of steam is sufficient to maintam turbine load. Operators can also adjust FD and ID
fan dampers based on absolute pressure m a furnace, but the four O2 analyzers per boiler are
known to be maccurate, therefore air flow control is also based on guesswork.
The existing O2analyzers of Russian design and manufacturer require frequent maintenance and
calibration. The steam boilers flue gas samples are drawn from the backpass after the
superheater and before the first stage reheater where pressure is slightly negative, temperature
about 550 C +/-. The sample line is about 108 1!lID m dia. and about 70 m long. Although
these analyzers are functional, they are subject to drift and significant lag time as well as
inaccurate readings due to air in-leakage. This results in less than optimum cQntrol of excess
air for efficient combustion which results in waste of fuel.
Environmental Monitoring
Downwind dispersion concentrations of ash, NO x , S02' CO2 are checked once per month by
power plant laboratory at 2.5, 5.0, 8.0 and 10 Km. The government district center sanitary
laboratory in L'VIV makes random tests when plant is at full load.
Condenser Cooling Water
Condenser cooling water is taken from an artificial lake which was created by damming a nver
at the same time the plant was constructed. The lake is used as a fish farm and chemicals
cannot be used to maintam condenser cle3.nIiness, therefore condenser fouling with CaC0 3 ,
MgC0 3 and organics is a significant problem.
Each condenser is cleaned twice per year and the average deposit thickness at the time of a
cleamng is 3-4 mm. At the time of a condenser cleaning, there is a loss of condenser vacuum
from 0.036 kg/cm 2 to 0.039 kg/cm 2 absolute pressure which causes a 5 MW loss in generator
output. Two condensers have Ukrainian design ball cleaning systems which were installed in
1990.
Boiler Makeup Water and City Water Treatment
Lake water makeup is heated and sent to four (4) 150 TIH clarifiers and six (6) 3.0 meter
diameter anthracite fIlters. From that point water is sent to the city hot water district heating
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system softeners and to the boiler makeup water demineralizer. City water demand is 300 TIH
and boiler makeup water demand is 240 T/H, and these two flows should be within the design
rating of the equipment. However, the ion exchange material in the demineralizer is in such
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