Outline Topic 1 Overview on The CirculatingWater System

Outline Topic: 1. Overview on The Circulating-Water System 2. System Classification 3. The Circulation System 4. Wet Cooling Tower 5. Wet Cooling Tower Calculations 6. Dry Cooling Towers 7. Cooling Lakes and Ponds 8. Spray Ponds and Canals รศ. ดร. สมหมาย ปรเปรม

The Circulating-Water System • • • Cooling water in condenser Cooling water for turbine Boiler building Fire protections etc. รศ. ดร. สมหมาย ปรเปรม

Power Plant Circulating Water Q Environment Q รศ. ดร. สมหมาย ปรเปรม

7. 2 System Classification 1. Once Through Systems: water is taken from a lake or river and pump through the condenser, where it is heated and then discharged back to the source. (Fig. 7 -1) 2. Closed Loop systems: water is taken from the condenser, pass through a cooling device, and returned to the condenser. The cooling devices; ie. Cooling tower, Spray pond, Spray cannel, Cooling lake. (Fig. 7 -2) 3. Combine Systems: Combine once-through system with a cooling device, such as a cooling tower. Open mode: cooling tower cools the circulating water before discharges it to the natural source. (Fig. 7 -3) Helper mode: Cooling tower share cooling duty. (Fig. 7 -4) รศ. ดร. สมหมาย ปรเปรม

Steam Turbine Steam Condenser Circulating pump Condensate to plant Natural water T 1 + R flow direction Figure 7 -1 Once-through circulating-water system รศ. ดร. สมหมาย ปรเปรม

Steam Turbine Cooling Tower Steam Condenser Circulating pump Makeup Pump Condensate to plant Natural water flow direction Figure 7 -2 Wet cooling tower operating in closed mode รศ. ดร. สมหมาย ปรเปรม

Steam Turbine Steam Condenser Cooling Tower Circulating pump Condensate to plant T 1 + TTD Alternative once through (T 1 + R) T 1 flow direction Figure 7 -3 Wet cooling tower operating in open mode. An alternative once-through system is shown by the dashed line. รศ. ดร. สมหมาย ปรเปรม

Steam Turbine Steam Condenser Cooling Tower Circulating pump Condensate to plant Alternative once through (T 1 + R) Bleed T 1 Alternate flow direction Figure 7 -3 Wet cooling tower operating in the helper mode. รศ. ดร. สมหมาย ปรเปรม

Exercise 7 -1 A 900 -MW powerplant of the pressurized-water nuclear-reactor type uses once-through cooling from a river. Regulations do not permit cooling water disd 1 arge back to the river hotter than 5°C above river ambient. Estimate (a) the necessary water flow, in kilograms per second, and (b) the reduction, in percent, in. this water flow if the plant efficiency is improved by 1 percentage point. Take cp for water = 4. 184 k. J/kg K. รศ. ดร. สมหมาย ปรเปรม

7. 3 The Circulation System 1. 2. 3. 4. 5. 6. An intake structure. A circulating-water pumping station. Circulating-water conduits Flow gate. Vacuum breaking system. Cold and warm water cannel. รศ. ดร. สมหมาย ปรเปรม