3 replies to this topic

[Narnia]

Dear members,

For cooling water treatment purposes i have to prepare the specification sheet and perform the required chemical calculations i.e required flow & pressure etc.

Please share with some calculations or guide me how to perform that

Thanks

[ankur2061]

Narnia,

You can follow the guidelines for chemical dosing as provided in the link below. Please note that the dosing calcualtions in the link below are for boiler and desalination plant but the methodology can also be applied to Cooling towers.

http://www.cheresour...al-for-boilers/

Regards,
Ankur

[Narnia]

Thanks for your information,
For boilers i have very detailed calculations of chemical dosing but for cooling towers i have not performed these calculations before.Please guide for cooling towers normally what type of chemicals are dosed and how much conc in terms mg/l / ppm maintained for every chemical.
Purpose of dosing each chemical??

Thanks

[breizh]

Narnia ,
To answer your question , only the supplier of Chemicals for Cooling water can tell you the needs . At first he should do an analysis of the Make up water (hardness, cl- ) and recommend a treatrment to prevent scale build up and corrosion .For corrosion prevention you will need to provide all the metallurgy in contact with cooling water and the service conditions.
Utilmately he will let you know about the blow down or the number of cycles for your operation.
Consult the big names like Nalco , GE Betz or local supplier .

I've added an example to support my comments


Customer: Attention: Reported By: Nalco copy to: 17-Feb-12 \ Cooling Water System Recc. Value Water analysis result MU CW. 350 CW. 175 CW. 75 Calcium hardness (ppm as CaCO3) 45.00 120.80 - 200.00 100 - 250 M-Alkalinity (ppm as CaCO3) 83.60 168.00 - 194.40 < 2,000 pH Value 7.91 8.43 - 8.37 8.5 - 9.5 Conductivity (micro s/cm) 240.00 565.00 - 662.00 < 1800 Iron (ppm as Fe) 0.45 0.24 - 0.39 <1.0 NALCO 3DT265(ppm as product) 89.50 - 75.90 80 - 120 Biological Glowth <10000 10,000 <10000 < 300,000 SRB 0.00 0.00 0.00 Nil. Note : MU = Make up water, CW.350, CW.175, CW.75 = Cooling Water No.350 , 175, 75


Notes :
Based on the size of your system you may choose manual blow down or continuous blow down.
A lot of money involved in cooling water treatment meaning you need several proposals ( treatment costs , guarantee of results ( corrosion rate , ...)



Hope this helps.

Breizh

Edited by breizh, 24 February 2012 - 02:34 AM.