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### Topic: oxigen transport in water  (Read 3091 times)

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#### urtula

• Regular Member
•   • Posts: 22
• Mole Snacks: +0/-0 ##### oxigen transport in water
« on: March 03, 2009, 12:53:21 PM »
hallo all,

I am doing a paper on oxigentransport in water, in my papers I have the following formula given: (Kla)at any temp = (Kla)at 20°C x (1.024)^T-20  (t= any temperature)

meaning that you can calculate the Kla value for any given Temperature, however you need to know the Kla value at 20°C ((Kla)20°C) , but how do I know this value? is this a fixed value? I do not think so because it depends on a lot of factors.
So how can I figure out what this Kla value at 20°C is ?

The Kla value is defined as the mass transfer coefficient in my text.
(strangely enough as 1/hours and not mass/hours)

and I also have a general formula to calculate the Kla value.
(Kla = ln(Cs-C1)-ln(Cs-C2)/ (t2-t1))
This is a formula that I can use, and I have to keep in mind at what temperature I did the tests.

I know have 3 differend Kla values for 3 types of water at a certain water temperature.
Imagine I did my tests at 20°C , then I would have my Kla at 20°C , but is this really the point? seems so stupid. Now I am wondering what they really mean with the (Kla)at t = (Kla)at 20°C x (1.024)^T-20 formula.
I do not understand the point of it if I have a general formula to calculte the Kla (at the temperature I did my tests).

and how to get that Kla value at 20°C ?
(Imagine I did my tests at 20°C , then I would have my Kla at 20°C , but is this really the point? seems so stupid. )

The only purpose at the moment I see in the formula is that you can calculate the Kla of your water for any temperature you want but what is the point in this if you do not know the Kla value at 20°C or if you have to calculte the Kla value of 20°C yourself.