20 Power Plant Open Cooling System in the Context of the Objectives …
411
Summary for Option 1. The solution analysed appears not to be cost-effective,
since for most of the year no problems are present with excessive water temperature after the condensers. Taking into account the results of water monitoring, the
number of days per year during which the installation would operate is estimated
at approximately 86 (summer months from July to September). The temperature
only exceeded 24 °C to an insignificant degree; the maximum temperature after
turbine set condensers was 28.6 °C. From the technical point of view, power plant
operating conditions should not change, since the cooler will be installed as an additional element before the water is discharged. It will not interfere in any way with
the internal turbine-boiler-generator system. The environmental problem potentially
associated with the operation of this system would be the use of chemicals: antiscalants used to complex bivalent ions in order to protect the cooler against the
formation of secondary deposits. A side effect, however, would be the discharge of
water additionally contaminated with chemical compounds into the receiving water
body.
20.3.5.3 Option 2 – Assuming the Replacement of the Current
Condenser Cooling System with Cooling Towers or Fan
Coolers
Figure 20.4 shows a technological diagram, including key operating parameters, for
the option under which the current cooling system based on turbine set condensers
is abandoned and replaced by evaporative coolers cooled with atmospheric air. It has
been assumed that the coolers must enable the generation of electricity even at high
(summer) air temperatures reaching 34 °C.
Under these conditions, the efficiency of the cooler decreases significantly and
the temperature of the water which cools the condensers increases, which results in a
decrease in electricity generation efficiency. If a constant capacity is maintained, this
means an increase in the power consumed by burning fuel. The extreme parameters
shown in Fig. 20.4 are indicated by the “
# ” superscript.
The required cooling capacity of a fan cooler or cooling tower should be approximately 390 MW under design conditions (Fig. 20.4). According to the ratio previously adopted, the construction of these facilities should require expenditure of
around PLN 94 million. It has been assumed that their integration with the power
plant system, including the necessary modifications, would mean capital expenditure
at the level of 30% of the capital expenditure on equipment, which results in an additional PLN 28 million. Therefore, the total value of fixed assets required is around
PLN 122 million. The annual depreciation of fixed assets would amount to approximately PLN 8.1 million (assuming depreciation of facilities over 15 years). Operating
costs and required repairs are estimated at approximately PLN 3.7 million per year
(3% of the investment outlay required per year). Therefore, the total operating costs
of the new cooling system amount to approximately PLN 11.8 million/year. Given
electricity production of 1375 GWh/year, this results in an increase in the unit price
of electricity generated by PLN 8.6/MWh.
411
Summary for Option 1. The solution analysed appears not to be cost-effective,
since for most of the year no problems are present with excessive water temperature after the condensers. Taking into account the results of water monitoring, the
number of days per year during which the installation would operate is estimated
at approximately 86 (summer months from July to September). The temperature
only exceeded 24 °C to an insignificant degree; the maximum temperature after
turbine set condensers was 28.6 °C. From the technical point of view, power plant
operating conditions should not change, since the cooler will be installed as an additional element before the water is discharged. It will not interfere in any way with
the internal turbine-boiler-generator system. The environmental problem potentially
associated with the operation of this system would be the use of chemicals: antiscalants used to complex bivalent ions in order to protect the cooler against the
formation of secondary deposits. A side effect, however, would be the discharge of
water additionally contaminated with chemical compounds into the receiving water
body.
20.3.5.3 Option 2 – Assuming the Replacement of the Current
Condenser Cooling System with Cooling Towers or Fan
Coolers
Figure 20.4 shows a technological diagram, including key operating parameters, for
the option under which the current cooling system based on turbine set condensers
is abandoned and replaced by evaporative coolers cooled with atmospheric air. It has
been assumed that the coolers must enable the generation of electricity even at high
(summer) air temperatures reaching 34 °C.
Under these conditions, the efficiency of the cooler decreases significantly and
the temperature of the water which cools the condensers increases, which results in a
decrease in electricity generation efficiency. If a constant capacity is maintained, this
means an increase in the power consumed by burning fuel. The extreme parameters
shown in Fig. 20.4 are indicated by the “
# ” superscript.
The required cooling capacity of a fan cooler or cooling tower should be approximately 390 MW under design conditions (Fig. 20.4). According to the ratio previously adopted, the construction of these facilities should require expenditure of
around PLN 94 million. It has been assumed that their integration with the power
plant system, including the necessary modifications, would mean capital expenditure
at the level of 30% of the capital expenditure on equipment, which results in an additional PLN 28 million. Therefore, the total value of fixed assets required is around
PLN 122 million. The annual depreciation of fixed assets would amount to approximately PLN 8.1 million (assuming depreciation of facilities over 15 years). Operating
costs and required repairs are estimated at approximately PLN 3.7 million per year
(3% of the investment outlay required per year). Therefore, the total operating costs
of the new cooling system amount to approximately PLN 11.8 million/year. Given
electricity production of 1375 GWh/year, this results in an increase in the unit price
of electricity generated by PLN 8.6/MWh.