Control Valve Sizing for Special Case

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SUBRAHMANIAN Active Contributor Join Date: Jan 2014 Posts: 12	Control Valve Sizing for Special Case 01/08/2014 9:52 AM
	Hi everyone, Am working for a hydroprocessing project. There are two control valve for a high pressure application, the critical pressure for this application is less than that of vapor pressure. Note that the application is two phase. My vendor is saying that this cannot be sized. Do any one have a solution for this, as my process confirmed that the conditions provided correct.
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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: Control Valve Sizing for Special Case 01/08/2014 10:29 AM
	The vendor is pointing out that with the process conditions advised, it is functioning as a flash boiler. Is that what is wanted? If so then it may well get wrecked in a short period of time, in which case the vendor is protecting its business reputation by declining to supply. The solution is to change the process conditions. __________________ "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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lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#2 Re: Control Valve Sizing for Special Case 01/08/2014 10:42 AM
	You're the customer. Tell him what size you need for your process conditions. Now, if you don't understand the process well enough to define it, and the equipment needed, you may be in the wrong line of work. First, define the process!!!!!!!!!!!!!! Then, you should be able to define the equipment needed.
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Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#3 Re: Control Valve Sizing for Special Case 01/08/2014 10:52 AM
	Hydroprocessing, eh? Could you give us a little tutorial on how to process some hydro, including the proposed temperature/pressure/change-of-state conditions, and maybe some flow rates? __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
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SHOCKHISCAN Guru Join Date: Nov 2007 Location: Eastern Arizona mountains on Route 666 about a mile from God's country Posts: 1676 Good Answers: 122	#4 Re: Control Valve Sizing for Special Case 01/09/2014 9:20 AM
	Contact other valve vendors. If after talking to the engineering application group of at least three of the major valve manufacturers and none will respond with sizing, your process application is more than likely flawed. __________________ They said; "Brain size?" I heard; "Train size?" so I said: "I'll take a small one, thank you."
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SUBRAHMANIAN Active Contributor Join Date: Jan 2014 Posts: 12	#5 Re: Control Valve Sizing for Special Case 01/14/2014 11:43 AM
	Thank you all for your replies. Still am waiting from process regarding few confirmation on the provided values, to solve this. But Vendor has also asked me if the application is out gassing, but am not very clear about this term? Do any one have any idea about OUT GASSING?
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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	#6 In reply to #5 Re: Control Valve Sizing for Special Case 01/21/2014 4:59 AM
	Call it boiling, then. Is it still unclear? __________________ "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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SUBRAHMANIAN Active Contributor Join Date: Jan 2014 Posts: 12	#7 Re: Control Valve Sizing for Special Case 06/11/2014 12:40 PM
	Thank you all. This was an out gassing application. Hence the vapor pressure mentioned here is a Vapor pressure of the lightest particle present in the mixture. So the VP can be greater than the critical pressure and this vapor pressure is called as pseudo vapor pressure. Finally My Vendor has provided me a valve suitable for this services. It was severe service valve with a special trim.
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lyn (1); PWSlack (2); SHOCKHISCAN (1); SUBRAHMANIAN (2); Tornado (1)

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