) react with the iron, nickel, or chromium in the vessel walls to form a protective or semi-protective metal sulfide scale ( FeScap F e cap S NiScap N i cap S
Equipment that remains sealed or idle during the turnaround but contains sulfide scales.
During normal refinery operations (particularly in hydroprocessing, desulfurization, and catalytic cracking units), hydrogen sulfide (
NACE SP0170 PDF 2021 provides a comprehensive framework for preventing and controlling corrosion in equipment and components used in petroleum refining and petrochemical environments. The updated standard reflects advances in technology, changes in industry practices, and lessons learned from recent corrosion failures. By adopting this standard, industries can improve safety and reliability, reduce maintenance and repair costs, enhance regulatory compliance, and increase efficiency and productivity. nace sp0170 pdf 2021
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When equipment must be opened to atmospheric air for repairs, cleaning, or internal inspection, the metal sulfide surfaces must be treated to prevent acid formation.
| Source | Description | | :--- | :--- | | | The official publisher. Offers the most direct access to the true PDF. | | ANSI Webstore | Authorized reseller of American National Standards. | | Techstreet / Accuris | Major industry provider for technical standards. | | GlobalSpec | Another provider with standards cross-referencing. | ) react with the iron, nickel, or chromium
Implementation of these standards is the responsibility of specialized inspection, operations, and maintenance teams during planned turnarounds.
: Covers the entire shutdown process, including downtime and the periods immediately preceding and following it (start-up). Target Materials : Focuses on common refinery alloys like UNS S30400 (304 SS) S31600 (316 SS) , and stabilized grades like
To protect stainless steel equipment that has been sensitized (sensitization occurs when exposed to temperatures between , common in hydrotreating/hydrocracking) from SCC. By adopting this standard, industries can improve safety
The standard applies to equipment susceptible to PTA SCC, including: Desulfurizing units Hydrocracking units Hydrotreating units Fluid Catalytic Cracking Units (FCCU) Crude and lube distillation units
While you may be searching specifically for a "NACE SP0170 PDF 2021," the industry's current authoritative document is the . This standard remains a cornerstone of refinery safety, providing critical, lifecycle-saving guidance for protecting equipment during shutdowns and startups from the dangers of polythionic acid stress corrosion cracking.
When utilizing an alkaline wash, use chloride-free or low-chloride water. High-chloride water can inadvertently trigger Chloride Stress Corrosion Cracking (Cl-SCC).
The primary goal is to prevent the rapid, intergranular cracking of "sensitized" stainless steels (those exposed to high temperatures that cause chromium depletion at grain boundaries). Timeline Protection