Inspectioneering
Inspectioneering Journal

Avoiding HTHA Failures in Existing Equipment

By John Reynolds at Intertek. This article appears in the November/December 2010 issue of Inspectioneering Journal

High Temperature Hydrogen Attack (HTHA) is a long known and still occurring degradation issue for fixed equipment construction materials in the hydrocarbon process industry where hydroprocess plants (hydrogen plus hydrocarbons) are in service. Though HTHA failures in these units are the focus of this article, it is important to recognize that HTHA damage can also occur in high pressure boiler tubes, hydrogen producing units, synthetic gas units, ammonia plants and other equipment where hydrocarbons may not be involved but high temperatures are involved. And as the title implies this article focuses on existing equipment in process plants which may have some HTHA issues generally not considered or associated with specifying new equipment.

Major failures from HTHA are not very common, but they do happen, sometimes with enormous safety and economic consequences because the incidents involve high pressure and high temperature releases of hydroprocess fluids. This article will outline how to avoid HTHA failures in existing equipment, by understanding the interaction of numerous HTHA factors, understanding and applying the latest edition of API RP 941(1), establishing and implementing Integrity Operating Windows (IOW’s)(2), monitoring and controlling operating conditions that might lead to HTHA, applying risk assessment techniques to HTHA susceptible equipment, and doing adequate inspection planning for HTHA. Figure 1 is a more complete visual outline of the HTHA issues that will be covered in this article, showing the “spider web” interaction between all the issues required to avoid HTHA failures.

Figure 1 - Avoiding HTHA FailuresFigure 1 - Avoiding HTHA Failures

There’s an old safety saying that goes something like: “What you don’t know can kill you”, and it is surely true when it comes to HTHA. Though this brief article will not tell you everything you might need to know about HTHA in existing equipment, it will provide an overview of how to go about avoiding and detecting HTHA and guide you to other resources from which you can continue to learn more.

This content is available to registered users and subscribers

Register today to unlock this article for free.

Create your free account and get access to:

  • Unlock one premium article of your choosing per month
  • Exclusive online content, videos, and downloads
  • Insightful and actionable webinars
GET STARTED
Interested in unlimited access? VIEW OUR SUBSCRIPTION OPTIONS

Current subscribers and registered users can log in now.


Comments and Discussion

There are no comments yet.

Add a Comment

Please log in or register to participate in comments and discussions.


Inspectioneering Journal

Explore over 20 years of articles written by our team of subject matter experts.

Company Directory

Find relevant products, services, and technologies.

Job Postings

Discover job opportunities that match your skillset.

Event Calendar

Find upcoming conferences, training sessions, online events, and more.

Industry News

Stay up-to-date with the latest inspection and asset integrity management news.

Blog

Read short articles and insights authored by industry experts.

Asset Intelligence Reports

Download brief primers on various asset integrity management topics.

Videos

Watch educational and informative videos directly related to your profession.