T
/ 5.8 x
1% x Q = 279.5
l/min¡@
Chemical treatment vs. Ozone treatment
Operating cost analysis of chemical treatment system for cooling tower:
Taking 2,500 RT cooling tower as an example
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1. The water circulation rate (Q): 13 l/min/RT x 2,500 RT = 32,500 l/min
1 RT = 13 l/min = 0.78 m3/h
2.
Evaporation loss (Q1): T
/ 5.8 x
1% x Q = 279.5
l/min
(T
=
change in temperature, T
=
5¢J)
3. Drift loss (Q2) = 0.001 x 1% x Q = 0.325 l/min
4. Cycles of concentration (COC) = 5
If COC is unknown, default is 5.
5. Blowdown rate (Q3) = 0.9 / (COC - 1) = 0.9 / (5 - 1) = 0.225
6. Blowndown load = 1
7. Blowndown (Q4) = Q3 x Q / 100 = 73.125 l/min
8. Make-up water (Q5) = (Q1 + Q2 + Q4) x (365 x 24 x 60 x 1) = 185,510 CDM/yr
9. Annual cost of make up water (Q6) = water cost in $/CDM x Q5
10. Chemicals cost (Q7): $/month x 12 = $/yr
Total annual operating cost = Q6 + Q7 = $/yr
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Note: Repair and maintenance cost is not included.
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Radiator of
cooling tower without ozone treatment
Operating cost analysis of ozone treatment system for cooling tower:
Taking 2,500 RT cooling tower as an example
¡@
1. The water circulation rate (Q): 13 l/min/RT x 2,500 RT = 32,500 l/min
1 RT = 13 l/min= 0.78 m3/h
2.
Evaporation loss (Q1): T
/ 5.8 x 1% x Q = 279.5 LPM
(T
=
change in temperature, T
=
5¢J)
3. Drift loss (Q2) = 0.001 x 1% x Q = 0.325 l/min
4. Cycles of concentration (COC) = 10
5. Blowdown rate (Q3) = 0.9 / (COC - 1) = 0.9 / (10 - 1) = 0.1
6. Blowndown load = 0.9
7. Blowndown (Q4) = Q3 x Q / 100 = 0.1 x 32,500 / 100 = 32.5 l/min
8. Make-up water (Q5) = (Q1 + Q2 + Q4) x (365 x 24 x 60 x 0.9) = 147,742 CDM/yr
9. Annual cost of make up water (Q6) = water cost in $/CDM x Q5
10. Electricity consumption:
Power consumption of cooling tower ozone equipment kW/h + Pump power consumption kW/h
11. Electricity cost (Q7):
Electricity consumption kW/h x daily operating hours x 365 x unit price of electricity = $/yr
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Total annual operating cost = Q6 + Q7 = $/yr
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Radiator of cooling tower with ozone treatment
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