Amine Corrosion | Materials And Corrosion Control

Damage Description

·         Corrosion depends on the design and operating practices, the type of amine, amine concentration, contaminants, temperature and velocity

·         Most damage can be traced to faulty design, poor operating practices or solution contamination

·         Temperatures above 220°F in the rich amine can lead to acid gas flashing and severe localized corrosion if the pressure drop is high enough

·         Corrosion is generally uniform at low velocities but high velocities and turbulence will cause localized thickness losses

Affected Materials

Control Methodology

·         For carbon steel, limit velocities to 3-6 fps for rich amine and
3-20 fps for lean amine solutions

·         Maintain HSAS levels to < 2%

·         In areas turbulence and local pressure drops are unavoidable, upgrade to 316 SS. Use 410SS for trays and internals in towers

·         Upgrade reboiler and reclaimer tubes to 316SS if chlorides are below 400 ppm

·         Blanket storage tanks with inert gas to prevent oxygen ingress

·         Remove solids preferably in the rich amine with filtration

Monitoring Techniques

·         UT scans or Profile Radiography for external inspection

·         Target hot areas such as the reboiler circuit, hot rich/lean amine piping and the stripper overhead piping

·         Corrosion probes or coupons can be useful.

·         Analysis of amine solutions on a regular basis

Inspection Frequency

KPIs

·         # of exceedances of analytical limits

Reference Resources (Standards/GIs/BPs)

·         SABP-A-013, Amine Unit Corrosion Control

·         J. Gutzeit “Process Industries Corrosion – The Theory and Practice” NACE International, TX, 1986, pages 171-189.