pressure and temperature dew point for compressed air - CR4 Discussion Thread

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syachah Active Contributor Join Date: Nov 2008 Posts: 16	pressure and temperature dew point for compressed air 12/01/2009 1:21 AM
	hi all can anyone clarify the different of pressure dew point and temperature dew poing for compressed air.
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#1 Re: pressure and temperature dew point for compressed air 12/01/2009 7:00 AM
	Pressure dew point is the pressure, at the system temperature, at which relative humidity reaches 100% and droplets of dew will form. Temperature dew point is the temperature, at system pressure, at which relative humidity reaches 100% and droplets of dew will form. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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syachah Active Contributor Join Date: Nov 2008 Posts: 16	#2 In reply to #1 Re: pressure and temperature dew point for compressed air 12/01/2009 8:20 PM
	dear PWslack why the pressure dew point is using the unit DEGREE CELSIUS , and the temperature dew point also same.In this case ... is it the 2 degree celsius of pressure dew point is same with the 2 degree celsius of temperature dew point. Actually 'im having problem water carry over ( more condensate) in the air dryer. is it the pressure dew point is related to the condensate discharge produced by air dryer.high pressure dew point in the air dryer system means more condensate discharge from the dryer.? syachah
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syachah Active Contributor Join Date: Nov 2008 Posts: 16	#3 Re: pressure and temperature dew point for compressed air 12/01/2009 9:41 PM
	why the pressure dew point is using the unit DEGREE CELSIUS , and the temperature dew point also same.In this case ... is it the 2 degree celsius of pressure dew point is same with the 2 degree celsius of temperature dew point. Actually 'im having problem water carry over ( more condensate) in the air dryer. is it the pressure dew point is related to the condensate discharge produced by air dryer.high pressure dew point in the air dryer system means more condensate discharge from the dryer.? syachah
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Amer--Ed Participant Join Date: Dec 2009 Location: USA Posts: 4	#4 In reply to #3 Re: pressure and temperature dew point for compressed air 12/01/2009 11:54 PM
	You are having water carry over for several reasons. But first, we need to know the air flow going into the dyer, type of dryer ( refrigerated/ desiccant), inlet temperature to dryer, ambient temperature at dryer location, humidity of ambient air, size of dryer (rated flow). Then I can give most likely suggestions for cause of water carryover.
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syachah Active Contributor Join Date: Nov 2008 Posts: 16	#5 In reply to #4 Re: pressure and temperature dew point for compressed air 12/02/2009 1:44 AM
	Dear Amed The air dryer specification as follow: type:refrigerated air dryer ( R22) Max.working pressure:10 barg Max.working temp:45 degree celsius Air flowrate:13.3 m3/min ambient temperature : 35 degree celsius. Pressure Dew point: 2-5 degree celsius Voltage/phase/frequency:230/1/50 The actual problem is the pressure dew point is abnormal...out of design range. we have measured the pressure dew point using the DP 300 mobile dew point instrument and we get the reading is 18 degree celsius at the outlet of the dryer.with this temperature , more condensate accumulated in the system and cause the water carry over. you have any idea? syachah
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ducon Guru Join Date: Dec 2006 Location: Hop around Toronto, New York & Karachi Posts: 1876 Good Answers: 19	#6 In reply to #5 Re: pressure and temperature dew point for compressed air 12/03/2009 2:08 AM
	Do you have in-line moisture separators with an air trap at the bottom to drain condensate PRIOR to the Air Filters of the Air Dryer? While you solve your problem, personally to safeguard my system - I always do this immediately to take away 95% of the load off the air filters. Steam in-line Moisture Separator : Spirax Sarco/Ayvaz/Gestra Application: Suitable for air, gas and steam applications were the entrained liquid load does not exeed 40% (by weight) of the separator.s maximum gas flow capacity. This is a traditional looking separator and many engineers simply prefer this configuration because they are accustomed to it. Performance: The Wright-Austin Type T entrainment separator, when properly sized, installad and drained, will remove 99% of all liquid droplet and solid particle entrainment where the droplet and/or particle size equals or exeeds 10 microns. Operation: Moisture-laden gas enters the inlet of the separator where it is deflected in a centrifugal downward motion. The entrained moisture is thrown to the outer wall and separated by a reduction in velocity. The separated liquid falls below the .Vortex Containment Plate. (VCP) where it cannot be re-entrained. Dry, clean exit gas is drawn from the vessel center and it flows upward through the outlet of the separator. ASME Code Construction: These type T separators are of welded steel construction in accordance with section 8. Division 1 of the ASME Code for unfired pressure vessels. Inlet and outlet connections can be rotated radially upon request. __________________ I not only use all the brains that I have, but all that I can borrow. Woodrow Wilson
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Amer--Ed Participant Join Date: Dec 2009 Location: USA Posts: 4	#7 In reply to #5 Re: pressure and temperature dew point for compressed air 12/03/2009 7:57 PM
	I do have a few ideas. First your outlet dewpoint is indeed high. On a service call I would be looking at the following things-----is the condensor coil clean ?---what is the temperature of the air going into the dryer ? the airflow you list--is that what the dryer is rated for ? what is the flow going in ? how compressors are feeding the dryer ? what kw are they? do you have an air receiver between the compressors and the dryer? does it have an automatic drain on the bottom ? is it working ? where in the system are you seeing the water ? how far away from the dryer ? I know this is a lot of questions, but it helps diagnose the problem and come to a solution.
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Users who posted comments:

Amer--Ed (2); ducon (1); PWSlack (1); syachah (3)

You might be interested in: Compressed Air Filters, Compressed Air and Vortex Cooling Tubes, Compressed Air Dryers

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