I have one query for the following case


Shell Thickness =18 mm with 10 mm CA
Wear Plate Width =No Wear plate
Shell Inside Diameter=2000mm


Circumferential Compression at Bottom of Shell:
= (Q*( K.9/( TEM9*( B+1.56 * sqrt( R * TEM9 ))))
= (25227 *(0.7603 /(8.0000 *(230.00 +1.56*Sqrt(1020.00 *8.0000 ))))
= -2018.60 kgf/cm²



As per my understanding the value of R shall be 1010(Radius+Corrosion Allowance) but in pvelite it is taking 1020 i.e. radius plus 2* CA.


Please clarify as soon as possible.

Regards,
Satish Yadav

Hi Satish,

You are correct. The value that was substituted into the term 'R' in the equation had an extra corrosion allowance added on to it. In PV Elite 2010 (not released at the time of this post) the horizontal vessel analysis will be per ASME VIII-2. Per Division 2, R will be the corroded mean radius of the shell.

Also in Division 2, the Circumferential stress in the shell without a ring sigma 6, invloves a k factor which is 0.1 for welded construction. This effectively lowers this particular stress 10 times.

Hopefully this helps.

Scott,

Why pvelite is cosidering extra corrosion allowance?

In pvelite 2010 you are going to design saddle supports as per ASME VIII Division 2 even though the vessel is designed as per ASME VIII Division 1.

Please clarify if my understanding is right.

Regards,
Satish Yadav

Still waiting for reply.

Regards,
Satish Yadav

Hi Satish,

Like Scott mentioned above, and it will be fixed for PV Elite 2010.

Yes, in pvelite 2010 the saddle supports will be analyzed as per ASME VIII Division 2.