Question

COOLING WATER TREATMENT
Question Paper
Objective Type (1 mark each):

The basic function of cooling tower is to remove heat from water. (True/False).
Heat is transferred from cold body to hot body. (True/False).
In a cooling tower, water travels upwards and air travels downwards. (True/False).
Keeping cooling tower deck in open condition is a good practice. (True/False).
Corrosion is an electrochemical reaction. (True/False).
Heat exchanger tube thickness is below 2 mm. (True/False).
With increase in COC, blow down & windage losses increases. (True/false).
Bacteria cant survive in absence of sun light. (True/False).
Algae cant survive in absence of sun light. (True/False).
Oxygen is required for formation of film by anodic inhibitors. (True/False).
Surface condensers & oil coolers do not have corrosion resistant metallurgy. (True/False).
In a thermal power plant, 10% of circulation rate water passes through TG Condenser
(True/False).
Scaling do not occur due to calcium & magnesium salts (True/False).
Scaling & deposition are nothing but the same things. (True/False).
Sulphate reducing bacteria are aerobic bacteria. (True/False).
MBT based biocide can be used above 8.2 pH. (True/False).
Gluteraldehyde based biocide cant be used above 8.5 pH. (True/False).
Effectiveness of chlorine decreases with increase in pH. (True/False).
Oil dispersant & bio-dispersant are based on the same chemical. (True/False).
Bacteria growth is high in circulating water than CT basin & S.S.F. (True/False).
Corrosion & scale inhibitors are dosed based on blow down & windage losses. (True / False).
Non-oxidizing biocides are dosed based on blow down & windage losses (True / False).
Azoles are best corrosion inhibitors for copper and its alloys (True / False)
Density of different metals & alloys is different (True / False)
Thickness of protective film formed by corrosion inhibitors shall be in microns. (True / False)
Chlorine di-oxide can be generated safely by mixing precursors directly with each other. (True / False)
Sodium chlorite & acid forms explosive mixture if mixes directly (True / False)


Answer the following questions in detail. (2 marks each):

Section I Cooling Tower Thermodynamics, Heat Exchangers, System Metallurgy
Why cooling water systems are needed?
Draw a sketch of cooling water system?
Why water is selected as coolant?
What is specific heat of water?
What is latent heat of vaporization of water?
What are the types of cooling water systems used in industries?
What are the main types & sub-types of cooling towers?
Name all the components of cooling tower.
What are the types of fills used in cooling tower?
What are side stream filters, its types and what shall be its ideal capacity?
What is the normal terminology used in open circuit cooling water system?
What is total hold up volume?
What is time/cycle?
How COC is calculated and what is the optimum COC?
Describe holding time index (HTI).
Give the formula of evaporation rate, blowdown & windage losses.
Why blow down is required in CW systems?
What is cooling tower approach and what is ideal approach for a cooling tower?
What is delta T of cooling tower?
What is range of cooling tower?
What is Terminal Temperature Difference (TTD) or Approach for condensing & non-condensing heat exchanger?
What is LMTD?
Give formula for Heat Transfer Coefficient (HTC).
What is Hydro Thermal Stress Coefficient (HTSC)?
How can the performance of CT be calculated?
What are the factors affecting TG Condenser performance?
Why vacuum is important in TG Condenser?
What are the normal metallurgies used in CW system?
What metallurgy is used for TG Condenser, Oil Cooler & Air Coolers tubes?
Draw sketch of heat exchangers which are in parallel & series.
What is meant by no. of CW passes?
Name the components of heat exchanger or condenser.
Draw a diagram of two pass vertical heat exchanger.
What are the different copper based alloys used for heat exchanger tubes?
What is the composition of stainless steel?
What is the composition of admiralty brass?
What are sacrificial anodes?


Section II - Water Chemistry & Analysis:
What are the main sources of make-up water?
What are the types of impurities present in cooling water & what is its impact on CW system?
What is Langlier Index & Ryznar Stability Index?

Answer 1

1). Answer: True.

2). Answer: False.

3). Answer: False.

4). Answer: False.

5). Answer: True.

6). Answer: True.

7). Answer :True.

8). Answer: False.

9). Answer: True .

10). Answer: True.

11). Answer: False.

12). Answer: False.

13). Answer:False.

14). Answer: False.

15). Answer: True.

16). Answer:True.

17). Answer: True.

18). Answer: True.

19). Answer :False.

21). Answer: True.

23). Answer: True.

24). Answer: False.

25). Answer: True.

27). Answer :True.

28). Answer: True.

29). Answer: True.

30). Answer: False.