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Thread: Milk chiller problem
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24-09-2010, 07:46 AM #1
Milk chiller problem
Dear friends,
pl help me to find out the problem
we have installed 20tr glycol chiller with ammonia systems for chilling 10,000ltr/hr milk by alfa laval PHE.
we designed for chilling milk from 8 degree to 6 degree celcious(i.e 6degree drop)
but pratically we give input milk is 6degree only
but we getting output milk temp is 3.5degr to 4 degree only(i.e is 2.5 degree drop only)
we gave the coolent side glycol temp is -5.5 degree to -6 degree
but we didn't get atleast 5 degree drop
the milk chiller heat transfer area is 3.84m^2
pl anybody help me
whether the designed system is correct or not?
?????????
u can send ur idea to my mail box
munakp@gmail.com
im verymuch thankful to you,
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24-09-2010, 07:53 AM #2
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Re: Milk chiller problem
There is no need to post your question in multiple threads.
we designed for chilling milk from 8 degree to 6 degree celcious(i.e 6degree drop)
If it is 6 degree drop than, if 8°C at enter mean that on exit will be 2°C.
Which is your case?
What is PHE model#?
What is measured glycol flow rate? What glycol type is inside and what concentration.
What is measured milk flow rate? Is it 10m^3/hr?
20 TR should be sufficent to cool 20% propilene glycol 5°C if flow is about 12000l/h
__________________Last edited by nike123; 24-09-2010 at 08:10 AM.
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24-09-2010, 08:04 AM #3
Re: Milk chiller problem
What are the input and output temperatures on the glycol side of the PHE?
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24-09-2010, 08:09 AM #4
Re: Milk chiller problem
thank you nike,
Sorry for the multi post, I am new to this RE, so i didn't read the rules im verysorry
we designed for chilling milk from 8 degree to 2degree celcious(i.e 6degree drop)
M10 not Exact,
Glycol flow rate is 27360 Ltr/hrMilk flow rate is 10,000 LTR/hr
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24-09-2010, 08:11 AM #5
Re: Milk chiller problem
Glycol input is -6*c
output is -2 *c
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24-09-2010, 08:13 AM #6
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24-09-2010, 08:18 AM #7
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24-09-2010, 08:18 AM #8
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Re: Milk chiller problem
Last edited by nike123; 24-09-2010 at 08:29 AM.
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24-09-2010, 08:28 AM #9
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24-09-2010, 08:37 AM #10
Re: Milk chiller problem
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24-09-2010, 08:41 AM #11
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24-09-2010, 08:50 AM #12
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24-09-2010, 08:55 AM #13
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Re: Milk chiller problem
What kind of temperature measuring device. (IC, surface probe, Pt100 Pt1000, K-type etc..)?
It should be measured with Pt1000 probe which is in copper sleeve inside glycol pipe or with some very accurate surface probe at some distance of HE (about 25-50 cm from HE). Or with this kit:
http://www.yellowjacket.com/images/p...atKit_case.jpg
5K (upper case) means 5 Kelvin
Kelvin is same as Centigrade degree when it is used as temperature difference unit. And, according to SI unit system, it is preferable unit to use when there is temperature difference in game.Last edited by nike123; 24-09-2010 at 09:06 AM.
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24-09-2010, 09:05 AM #14
Re: Milk chiller problem
Glycol is to cold, or milk velocity is to low.
Is the milk flow consistant?
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24-09-2010, 09:20 AM #15
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Re: Milk chiller problem
If you want that your PHE is at maximum exchange capacity, than you need introduce concept of thermal length.
That mean if you want temperature drop on milk side of 6K, than you also need temperature drop on glycol side of 6K. You do that by changing flow of glycol to get same "thermal length".
Edit: Ignore this since I forgot to care about frost.Last edited by nike123; 24-09-2010 at 10:07 AM.
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24-09-2010, 09:22 AM #16
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24-09-2010, 09:33 AM #17
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24-09-2010, 10:09 AM #18
Re: Milk chiller problem
ya alredy it has been installed, and gave it to full force full open in glycol side @-6*C and as well as 10,000ltr/hr of milk @ 6*C as input, but milk output is only 2*C drop(i.e 4*)
so pl give the correct parameter for chilling the milk 6*C to 2*C,
so im greatful to uuu
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24-09-2010, 10:25 AM #19
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24-09-2010, 02:42 PM #20
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Re: Milk chiller problem
With that surface of PHE and flow rates you presented you could only go with -4°C glycol at inlet and 1°C at outlet (13,2 m^3/h) if you wish that 10000l/h milk is cooled from 8°C to 2°C (1K approach).
If you increase surface to 5,9m^2 than you could go with -2°C glycol at inlet and 1°C (22m^3/h)at outlet if you wish that 10000l/h milk is cooled from 8°C to 2°C (1K approach).
Last edited by nike123; 24-09-2010 at 02:50 PM.
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24-09-2010, 07:05 PM #21
Re: Milk chiller problem
Everyone seems to be in agreement that -6C is too cold. The glycol should not be colder than -4C.
Last edited by Gary; 24-09-2010 at 07:10 PM.
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