Tips on Establishing an Inspection Strategy for a Fertilizer Plant

The following question was posed by a member of the Inspectioneering Community:

I am working in a fertilizer plant and our inspection team is very new. I was wondering if professionals in similar plants could share their knowledge related to inspection work. Please elaborate on details about the inspection function, as well as the main subjects we should focus on.

Inspectioneering Journal is home to an ever-growing amount of articles on this subject, written by some of the "best and the brightest." I'd like to add some thoughts of my own on the topic of establishing a fertilizer plant inspection strategy.

Resources

In many ways, fertilizer plants are no different than most process industry plants including refineries and petrochemical facilities. Information in documents like API 510, 570, 653 and RPs 580, 581, 571, 577, 579, etc. is essential. There are also some good ASME documents, in addition to the pressure equipment construction codes that are quite helpful, e.g. PTB-1, PCC-1,2 and 3, etc.

If it is an ammonia fertilizer plant, NACE has some very good reference information on managing equipment in anhydrous ammonia service. I participated in the original committee with Sheldon Dean of Air Products and others in creation of the first version of this reference document during my time at Monsanto. Documents are available that cover inspection of large above ground storage tanks. I highly recommend you purchase them as references. 5A192, (2004 Edition), Integrity of Equipment in Anhydrous Ammonia Storage and Handling, is a great place to start. This should cover ammonia SCC too. Materials and inspection practices should be covered. The API 510, 570, and 653 inspection codes, and supporting documents (572, 573, 574, etc.) are fundamental for pressure vessel, piping, and above ground storage tank inspection programs.

Of course, there are numerous articles in the IJ covering organization and establishment of pressure equipment integrity programs. Start there. The other documents previously referenced are covered.

Methods

Depending upon materials handled, external environment, and materials of construction, you will likely run into CUI issues (API is currently developing a CUI inspection RP 583). Also, if you have any reformer heaters, be sure to include inspection and NDE/NDT methods that focus on creep, as well as management for remaining life. There may be areas where high temperature hydrogen attack (HTHA) should be considered too. Hydrogen partial pressures and temperature versus materials of construction need to be considered. API's RP on HTHA (API RP 941) is an essential reference. Another great reference is API's RP 571 covering damage mechanisms in the refining and petrochemial industries. You should also download the updated version of The 101 Essential Elements in a Pressure Equipment Integrity Management Program by John Reynolds (see below). It covers most of the areas that should be a part of your inspection and fixed equipment reliability program.

Be aware of corrosive fumes around equipment that can cause external corrosion too. Minimize leaks.

In summary (and this is by no means complete), only some of the damage mechanisms to be considered in developing an effective inspection and reliability strategy might be:

• CUI - Corrosion under insulation
• Anhydrous ammonia stress corrosion cracking
• Creep
• High Temperature Hydrogen Attack
• Heat exchanger tube and other equipment types corrosion
• HCl and HNO3 acid corrosion if applicable
• ...and more.