Rule Thumb on Retiring Boilers/Pressure Vessels

[vernierb]

Hi,

New to forum, so if this has been discussed forgive me (did a search and didn't find anything).

Essentially we have some very old boilers/pressure vessels here on site (approaching 60 years in service), and I am wondering if there is a general rule of thumb on when they should be retired/taken out of service?

Obviously we are conducting all the required inspection/testing, which they are passing, thus we keep them in service. But as stated above was wondering if at a certain point it is just recommended to retire/replace boilers/pressure vessels?

Thank you,
Brian

 

[Duwe6]

Nope. Other than the usual "Does the cost of repair equal the cost to replace?"

At 60 years, they should be checked for fatigue cracking [probably at least every 5 years, if no cracks are being found.]

 

[MJCronin]

vernierb,

I agree with Duwe6.... there seems to be no general ruled of thumb for the retirement of pressure vessels or boilers.

Older, water-tube boilers that repeatedly crack at the steam drum are frequently candidates for retirement simply because of the cost of repair.

Older boilers and vessels are commonly found in abandoned process facilities. It is frequently cheaper to abandon equipment than to refurbish and replace.

Firetube boilers are somewhat easier to refurbish and retube than watertube boilers.

The Cleaver Brooks (firetube boiler) people claim: "average life exceeds 25 years with many cases exceeding 50"

Pressure Vessels seem to go on forever..... or at least until the new owner loses all of the documentation..!!

MJCronin
Sr. Process Engineer

 

[TGS4]

Today I got involved with a vessel originally fabricated in 1942! Much of the current metal is from a 2007 weld-overlay buildup, but the guts are still vintage. If it still works and ain't broke, don't throw it away.

 

[vernierb]

Thank you for the input everyone. Very much appreciated. I was thinking along the same lines but wanted to get some input from others in the industry. Thanks again.

 

[MJCronin]

ABMA has an interesting position on this issue:

http://www.abma.com/specification-design-life-requirements.html

There are several firms that will perform a "life assessment" on an existing boiler and give you a report on their "best guess" for a remaining life.

Bottom line: boilers can be abused, neglected and operated at temperatures and pressures far too high.... these all decrease the owner's useful life.

MJCronin
Sr. Process Engineer

 

[racookpe1978]

Riveted, welded, or bolted?

2014 - 60 = 1954. Welding was pretty reliable by then on the common alloys, but had only been in common use since the mid-40's.

 

[CollinsCombustion]

vernierb

This is tough to answer. How well have they been taken care of. Do you have any refractory issues? Are you looking for better efficiency or do you have emission requirements to meet. Sometimes installing a better control system is all that is necessary.

I've worked on so many boilers as old as 1940 that are going strong. Great Lakes Naval comes to mind. GLN has a 100kpph saturated four burner boiler that runs rock solid...

Darrell Collins

http://www.collinscombustion.com