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5. COOLING SYSTEM
5.1 General
The cooling system consists of the following systems:
- Steam condenser system
- Air cooler system
- Oil cooler system
- Others
Basic design information for circulating cooling water
Circulating cooling water volume: !--mstheme-->
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Q=3960 m3/h, including |
!--mstheme--> |
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Condenser |
3700 m3/h |
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Air cooler |
140 m3/h |
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Oil cooler |
80 m3/h |
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Others |
40 m3/h |
5.2 COOLING WATER SYSTEM
5.2.1 Main design information
Water circulation system is used for cooling the condenser of steam turbine and air cooler & oil cooler of power station. After heat exchanging with the equipments, temperature of cooling water rises about 17�? The hot water will be sent back to cooling tower by hot water pump. After exchanged with air in the tower, the hot water is cooled down to 30�?and then flown to the cooling water basin then flows to the condenser by gravity. There is about 2-3% of the water will be lost during the operation and it will be maker up by cleaning geothermal water piping in the mill.
One side filtrater is set in this system, so a portion of the circulation water can be filtrated, in this case the water quality can be reached. A portion of cooled water will be re-flooding into the ground through a combination seal well and spreader channel.
The cooling water constant quality shall be maintained by means of chemical treatment defined by pH control and microbiological control. Chemical treatment of the cooling water shall be applied to achieve two specific objectives:
--to maintain the pH of the cooling water to an optimum value of between 5 and 6.5
--to prevent biological fouling of the cooling tower
5.2.2 Equipment selection and structures
The cooling tower is of a mechanical forced draft counter-flow type. The material of tower structure is FRP (Fiber Reinforced Plastic) in stead of wood usually applied. In case of FRP structure, fire fighting system is not required and skilled carpenters are not required.
The circulating water requires bypass filtering treatment for removal of impurities and sludge generated during circulation. Operation and backwash of the valveless filter is fully automatic.
The hot water pump will be two groups, one group has 3 pumps (1 standby), pump model Q=1000 m3/h, H=20 m. The pump will take water from the catchment tank of condenser, and transfer to the cooling tower.
The NaOH liquor will be added into the system to adjust the PH of water, the device includes a solution tank and two chemical pumps. The volume of tank is 10m3, the model of pump is: Q=4-40l/h, H=20 m
5.2.3 Location of Cooling Tower
The cooling water tower shall be located so that prevailing winds will not blow towards the power plant buildings as the mist and vapors may be corrosive and obnoxious, and humid air circulation, which would reduce tower performance, shall be avoided.
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