COOLING TOWER AT COAL FIRE POWER PLANT TYPE

about cooling tower

1. COOLING TOWER Richo Pratama Hendrawan R BOP Technician PT. CIREBON POWER SERVICES

2. Content What is cooling tower? Kind of cooling tower ? Equipment of cooling tower? Cooling Tower Efficiency Calculations? Maintain of cooling tower?

3. What is cooling tower? A cooling tower is a specialized heat exchanger in which air and water are brought into direct contact with each other in order to reduce the water's temperature. Cooling towers are a special type of heat exchanger that allows water and air to come in contact with each other to lower the temperature of the hot water. During the cooling tower working process, small volumes of water evaporate, lowering the temperature of the water that’s being circulated throughout the cooling tower. In a short summary, the purpose of a cooling tower is to cool down water that gets heated up by industrial equipment and processes. Water comes in the cooling tower hot (from industrial process) and goes out of the cooling tower cold (back into the industrial process).

4. What is cooling tower?

5. What is cooling tower?

6. Type of cooling tower systems? Crossflow Cooling Towers Counterflow Cooling Towers Forced Draft & Induced Draft Cooling Towers Process Natural Draft & Fan Assisted Natural Draft Cooling Towers Factory Assembled Cooling Towers (FAP) Factory Assembled Product Field-Erected-Towers (FEP) Field Erected Product

7. Type of cooling tower systems?

8. Type of cooling tower systems?

9. Equipment of cooling tower? MOTOR FAN BLADE GEAR REDUCER COUPLING SPACER

10. Equipment of cooling tower? Fan blades Gearbox reducer Coupling spacer Drive eliminator Filler Spray nozzle Distribution pipe

11. Equipment of cooling tower? Fan blade Filler Spray Nozzle Gearbox reducer Coupling spacer Drive Eliminator

12. Cooling Tower Efficiency Calculations The performance of the cooling tower depends on various parameters like Range & Approach. We shall see those terminologies in Detail. Range : The difference between the Hot Water Temperature (Cooling Tower Inlet) Temperature and Cold water (Cooling Tower Outlet) temperature Range = Hot Water Temperature – Cold Water Temperature

13. Cooling Tower Efficiency Calculations Approach: The difference between the Cold Water Temperature (Cooling Tower Outlet) And ambient Wet Bulb Temperature. Approach = Cold Water Temperature – Wet Bulb Temperature

14. Cooling Tower Efficiency Calculations The calculation of cooling tower efficiency involves the Range and approach of the cooling Tower. Cooling tower efficiency is limited by the ambient wet bulb temperature. In the ideal case, the cold water temperature will be equal to the wet-bulb temperature. This is practically not possible to achieve. This requires very large tower and results in huge evaporation and windage or drift loss resulting in a practically not viable solution. In practice, the cooling tower efficiency will be in between 70 to 75%. but the achievement of the approach must be made as optimal as possible so that the cooling tower produces optimal cooling.

15. Cooling Tower Efficiency Calculations Cooling Tower Efficiency = (Hot Water Temperature – Cold water Temperature) x 100 (Hot Water Temperature – Wet bulb temperature) Or Simply Cooling Tower Efficiency = Range x 100 (Range + Approach)

16. Other Cooling Tower Calculations cycle of concentration (COC) -> The cycle of concentration is a dimensionless number. It is a ratio between parameter in Cooling Water to the parameter in Makeup water. The cycle of concentration normally varies from 3.0 to 7.0 depending on the Process Design. It is advisable to keep the Cycle of concentration as high as possible to reduce the makeup water requirement of the cooling tower. At the same time, the higher cycle of concentration increases the dissolved solids concentration in circulating cooling water which results in scaling and fouling of process heat transfer equipment.

17. Other Cooling Tower Calculations Draw off or Blowdown -> As the cooling water circulates the cooling tower part of water evaporates thereby increasing the total dissolved solids in the remaining water. To control the Cycle of Concentration blow down is given. Blowdown is the function of Cycle of concentration. Blowdown can be calculated from the formula: B = E/ (COC-1) B = Blow Down (m 3 / hr ) E = Evaporation Loss (m 3 / hr ) COC = Cycle of Concentration. Varies from 3.0 to 7.0 depending upon Manufactures Guidelines

18. Other Cooling Tower Calculations Evaporation loss Evaporation Loss in the cooling tower is calculated by the following empirical equation. E = 0.00085 x R x 1.8 x C E = Evaporation Loss (m 3 / hr ) R= RangeC = Circulating Cooling Water (m 3 / hr ) (Reference: Perry’s Chemical Engineers Hand Book ) Alternatively, The Evaporation loss can be calculated from the heat balance across the cooling tower. The amount of heat to be removed from Circulating water according to Q =  m C p   DT is C x C p  x R .   The amount of heat removed by evaporative cooling is  Q = m x  Hv is E x H V On Equating these two, we get E = C x R x C p / H V E = Evaporation Loss in m 3 / hr C= Cycle of Concentration R= Range in °C Cp = Specific Heat = 4.184 kJ / kg / °C H V  = Latent heat of vaporization = 2260 kJ / kg

19. Other Cooling Tower Calculations Drift or Windage Loss Drift loss of the cooling tower is normally provided by the cooling tower manufacturer based on the Process design. If it is not available it may be assumed as For Natural Draft Cooling Tower D = 0.3 to 1.0 * C /100 For Induced Draft Cooling Tower D = 0.1 to 0.3 * C /100 For Cooling Tower with Drift Eliminator D = 0.01* C /100

20. Other Cooling Tower Calculations Cooling tower mass balance gives an idea about make-up water requirement. Cooling Tower Makeup has to substitute the water losses resulting from Evaporation, Windage and Blowdown. M = E + D + B M = Make up water Requirement in m 3 / hr B = Blow Down in m 3 / hr E = Evaporation Loss  in m 3 / hr D = Drift Loss in m 3 / hr

21. Maintain of cooling tower? Performing routine preventive maintenance is paramount for consistently achieving the desired temperature and flow rate, and plays an important role in maximizing cooling tower operating life. Manufacturers conscious of the importance of maintenance offer many features that simplify these procedures, saving time and money. Kind of maintain cooling tower: Maintain Fan Blade Maintain gearbox reducer3. Maintain spray nozzle and drive eliminator Repair valve riser inlet Cooling Tower

22. Maintain Fan Blade Lamination fan blade Install Leading Edge

23. Maintain gearbox reducer Replace oil gearbox reducer Check alignment at gearbox coupling spacer and motor Take sample oil

24. Maintain spray nozzle and drive eliminator Replace Spray nozzle Inspect filler condition

25. Repair valve riser inlet Cooling Tower Repair butterfly valve 32 inch Inspect surface inlet pipe riser

26. Breakdown Gearbox reducer Breakdown gearbox drive Inspect every tooth profile Inspect lubricant condition

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