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#34377 - 04/15/10 10:03 PM Pressure thrust inclusion in WRC calculation
Bipin Offline
Member

Registered: 02/25/10
Posts: 13
Loc: India
Hello,
Please let me know, once the client has given the allowable loads for the nozzle, shall we additionaly include the pressure thrust for WRC calculation?

When exactly the pressure thrust is to be included in WRC calculation?

Do we need to check manholes/Handholes with blindflange for only Pressure thrust in WRC 107?

Please revert.

Regards,
Bipin
L & T

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#34383 - 04/16/10 12:06 AM Re: Pressure thrust inclusion in WRC calculation [Re: Bipin]
Mukesh Offline
Member

Registered: 11/12/06
Posts: 125
Loc: Ahmedabad, Gujarat, India
Bipin,

If client has not asked to consider pressure thrust then no need to consider the same.

More information on pressure thrust is available in the article in July 2001 COADE Newsletter. If you dont get then ask me at "theculminates@yahoo.com" I will provide you.

You dont need to do local load analysis for Manhole/Handholes etc.

Mukesh Chopra
www.theculminates.com
M: +91-9428500192

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#34394 - 04/16/10 06:20 AM Re: Pressure thrust inclusion in WRC calculation [Re: Mukesh]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 743
Loc: Houston, TX
Pressure thrust is just added algebraically to the radial load 'P' (WRC 107). If your radial load is positive (radially inwards), taking pressure thrust in account may actually help you.
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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#34453 - 04/19/10 10:23 AM Re: Pressure thrust inclusion in WRC calculation [Re: Ray_Delaforce]
M.SHUKLA Offline
Member

Registered: 06/05/08
Posts: 55
Loc: INDIA
Dear All,

As said by Mr. Ray, Pressure Thrust (PT) is algebraically added in radial load i.e

a) P radially inward => +P + (-ve) PT
b) P radially outward => -P + (-ve) PT

Now, My question is (irrespective of any client specification):

In Reactor Regenerator section, the spent catalyst nozzle has a bellow in it.
=> Does pressure thrust needed to be applied in the spent catalyst nozzle?
=> Does pressure thrust needed to be applied to all other nozzles seeing the criticality of nozzle?







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#34471 - 04/20/10 07:52 AM Re: Pressure thrust inclusion in WRC calculation [Re: M.SHUKLA]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 743
Loc: Houston, TX
The introduction of the bellows could throw an entirely different perspective on this issue. The simple question to ask is: Do the bellows relieve the thrust or not.
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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#34477 - 04/20/10 10:03 AM Re: Pressure thrust inclusion in WRC calculation [Re: Ray_Delaforce]
M.SHUKLA Offline
Member

Registered: 06/05/08
Posts: 55
Loc: INDIA
Yes, bellows are thrust relieving.
But I couldn't understand what does this mean. As far as I know, bellows are designed or used where there is large thermal difference ( as in some cases of fixed tube sheet design)

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#34943 - 05/13/10 01:20 PM Re: Pressure thrust inclusion in WRC calculation [Re: M.SHUKLA]
M.SHUKLA Offline
Member

Registered: 06/05/08
Posts: 55
Loc: INDIA
I didn't got any answer.
Please Respond

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#35362 - 05/13/10 04:17 PM Re: Pressure thrust inclusion in WRC calculation [Re: M.SHUKLA]
Mandeep Singh Offline

Member

Registered: 12/15/99
Posts: 600
Loc: Houston, Tx, USA
Shukla,

There is no black and white answer to your question. As Mukesh pointed out, refer to the newsletter article (July 2001 COADE Newsletter), from the COADE website, go to Support -> Mechanical Engineering News.

It depends upon flexibility of the piping attached to the nozzle. If there is no piping attached to the nozzle, it just has end cover. Then, you would apply the pressure thrust.

But, there is another problem if you use WRC 107 and apply pressure thrust, the curve for the radial load gets exceeded very easily and this can give very conservative and error some results.

So, if you have access to FEA then you can consider pressure thrust. If you rely on WRC 107 then see if the curves are exceeded or not and use your judgment.

_________________________
Best Regards,
Mandeep Singh
CADWorx & Analysis Solutions
Hexagon PPM

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#35400 - 05/14/10 10:42 AM Re: Pressure thrust inclusion in WRC calculation [Re: Mandeep Singh]
M.SHUKLA Offline
Member

Registered: 06/05/08
Posts: 55
Loc: INDIA
Mandeep,
I understood your's & Mukesh's answer & already read the article. Now listen:

Refer the fig.
a.My flow of catalyst is from top to bottom.
b.Bellow comes first in the path.
c.Then comes the slide valve.

Now, consider the case-1 when slide valve is open, pressure of both the equipment is same. Now, in this case

1.1) what is the function of bellow (except for adjusting thermal expansion) & as earlier said that bellow is pressure compensating.
2.1) In FEM I need to include pressure thrust (particularly in this case) on both the nozzles.
3.1) What is pressure compensating bellow.



Attachments
untitled.bmp (589 downloads)



Edited by M.SHUKLA (05/14/10 10:43 AM)

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