The alkaline wash neutralizes any polythionic acid as soon as it forms.
Find the of the standard (e.g., 2018 or 2024 if released).
Defines the need for dry, oxygen-free conditions. How to Obtain NACE SP0170 PDF nace sp0170 pdf
Whether you are establishing a lay-up procedure for a turnaround or investigating a failure, this standard provides the roadmap you need. Don’t rely on guesswork—get the standard, study the prevention methods, and protect your assets.
The presence of moisture, oxygen, and sulfide scales creates polythionic acid at ambient shutdown temperatures. The alkaline wash neutralizes any polythionic acid as
In the high-stakes world of petroleum refining, the integrity of process equipment is paramount. Yet, during planned or unplanned shutdowns, a stealthy and dangerous form of degradation known as can threaten austenitic stainless steel components. The authoritative document that guides industry professionals in combating this corrosion phenomenon is NACE SP0170 , a standard practice published by the Association for Materials Protection and Performance (AMPP), formerly known as NACE International. This article provides an in-depth guide to understanding NACE SP0170, its key provisions, and most importantly, how to acquire the official "nace sp0170 pdf" for your engineering library.
The standard emphasizes that the best protection often starts with selecting materials and fabrication practices that are resistant to sensitization in the first place, thus lowering the overall risk of PTA SCC. How to Acquire the NACE SP0170 PDF How to Obtain NACE SP0170 PDF Whether you
Austenitic stainless steels (e.g., 300 series) and some alloys can become sensitized (chromium carbides precipitate at grain boundaries) during high-temperature service.
When a processing unit is running normally, the environment inside the equipment is typically oxygen-free. However, when the unit is shut down for inspection, cleaning, or repairs, the introduction of air (oxygen) and moisture can trigger the formation of polythionic acids. NACE SP0170 provides the exact chemical, mechanical, and procedural steps to keep these assets safe during these critical windows. The Science of Polythionic Acid Cracking (PTA-SCC)
If utilizing an alkaline wash, pre-mix the soda ash solution using demineralized or low-chloride water. Ensure corrosion inhibitors are added if specified.
By removing oxygen, the sulfide scales cannot react to form polythionic acids, even if moisture is present. 2. Alkaline Washing of Equipment Surfaces