Menu
Search
Filters
Close
Menu

Case Study - Suspected SAC In Recovery Boiler Screen Tubes Revealed A Manufacturing Defect

Picture for Case Study - Suspected SAC In Recovery Boiler Screen Tubes Revealed A Manufacturing Defect
Available for download
Product Number: 51321-16587-SG
Author: Catherine A. Noble, P.E.
Publication Date: 2021
$0.00
$20.00
$20.00

A longitudinal crack in the swaged section of a screen tube was discovered in the black liquor recovery boiler at a paper mill. An adjacent tube to the failure contained an “indication” of a crack when X-rayed. The mill originally suspected stress assisted corrosion (SAC). These tubes were examined in the lab, and neither appeared to be damaged due to operation. Further investigation determined that the failure originated from a manufacturing flaw at the external tube surface in the swaged section. The examination indicated that the condition was likely isolated and not indicative of the general condition of other tubes with similar service. The mill planned to remove all of the screen elevation swaged tubes from the boiler during the next outage. These tubes were examined using phased array ultrasonic testing (PAUT) for SAC and no indications were detected. As a follow up, two additional tubes from the inspection were also metallurgically examined and there was no evidence of the manufacturing defect. This was confirmed to be an isolated incident.

Key words: black liquor recovery boiler, swage, screen tube, phased array ultrasonic inspection, manufacturing defect, stress assisted corrosion, corrosion fatigue.

A longitudinal crack in the swaged section of a screen tube was discovered in the black liquor recovery boiler at a paper mill. An adjacent tube to the failure contained an “indication” of a crack when X-rayed. The mill originally suspected stress assisted corrosion (SAC). These tubes were examined in the lab, and neither appeared to be damaged due to operation. Further investigation determined that the failure originated from a manufacturing flaw at the external tube surface in the swaged section. The examination indicated that the condition was likely isolated and not indicative of the general condition of other tubes with similar service. The mill planned to remove all of the screen elevation swaged tubes from the boiler during the next outage. These tubes were examined using phased array ultrasonic testing (PAUT) for SAC and no indications were detected. As a follow up, two additional tubes from the inspection were also metallurgically examined and there was no evidence of the manufacturing defect. This was confirmed to be an isolated incident.

Key words: black liquor recovery boiler, swage, screen tube, phased array ultrasonic inspection, manufacturing defect, stress assisted corrosion, corrosion fatigue.

Product tags
Also Purchased
Picture for 02472 PROCEDURE USED FOR ROOT CAUSE...
Available for download

02472 PROCEDURE USED FOR ROOT CAUSE ANALYSIS: Pitting in Stainless Steel Tubes Associated with MnO2 Deposition

Product Number: 51300-02472-SG
ISBN: 02472 2002 CP
Author: Richard W. Lutey and George M. Richardson
$20.00
Picture for 01424 Superheater Tube Corrosion in Changing
Available for download

01424 Superheater Tube Corrosion in Changing Operation Conditions of Recovery Boilers

Product Number: 51300-01424-SG
ISBN: 01424 2001 CP
Author: Lasse Koivisto, Martti Makipaa and Maria Oksa
$20.00
Picture for 00691 EXPERIENCE WITH TITANIUM HEAT EXCHANGERS
Available for download

00691 EXPERIENCE WITH TITANIUM HEAT EXCHANGERS IN REFINERY SERVICES

Product Number: 51300-00691-SG
ISBN: 00691 2000 CP
Author: Deyuan Fan, William C. Fort ili, Richard J. Horvath
Publication Date: 2000
$20.00

Several experiences with the use of titanium heat exchangers in refining processes are summarized. These involve distillation column overhead condensers in atmospheric crude distilling units, fluid catalytic cracking units, delayed coking units, and sour water strippers. The causes of problems are discussed. Needs for additional data are highlighted.
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support