NDE for High-Temperature Hydrogen Attack (HTHA): A Joint

NDTMA 2020 Annual Conference

NDE for High-Temperature Hydrogen Attack (HTHA):

A Joint Industry Program (JIP)Success Story

Michael NugentPrincipal EngineerLPI, Inc.NY, NY

Golden Nugget Hotel, Las Vegas, NV February 11-13, 2020

Technical AdvisorSNI

State College, PA

The Urgency for Viable NDT Methodology

In 2010, there was a multi-fatality incident in a refinery that seriously put into question the NDE community’s ability to reliably assess equipment

condition in High Temperature Hydrogen Service.

Through a Joint Industry Project (a consortium of 6-10 Owner Users), the deficiencies were indeed

highlighted, reviewed and a new approach has led to major revisions in the inspection methodologies.


AbstractThis restored confidence with NDE inspections and has paved the way for Fitness for Service methodologies to evolve to meet the industry needs.

A brief overview of this 6+ year project


Hydrogen is crucial in fuel manufacture


Presentation Outline

• The Bad (HTHA Failure subsequent CSB Alert)

• The Ugly (Pre-2014 State of the Art for NDE Inspection for HTHA

• The Good (JIP HTHA NDE Response and Worldwide Training Programs)


The Bad: What is HTHA

• Damage Mechanism well known since the 1930’s (Ammonia Synthesis)

• Function of material alloy content, temperature, partial pressure H2, time, stress and operational upsets

• Temperatures must be above 400 F (the hotter the more extensive the attack)

• Atomic Hydrogen (H+) is necessary, higher the pressure (concentration), the more extensive the attack

• Damage is cumulative over time and does not reverse• Stress (applied or residual) plays a factor


The Bad: HTHA

HTHA results from hydrogen service at elevated temperatures and pressures. The hydrogen (H+) reacts with carbides in steel to form methane (CH4) which cannot diffuse through the steel. (Play Graphic)

C

H

CH4


It is a Progressive Damage (Play Graphic)

The loss of carbide causes an overall loss in strength. Methane pressure builds up, forming microfissures that may combine to form cracks.

The Bad: HTHA


THE UGLY: NDE ROUND ROBIN• 9 Owner-Users Sponsors (Big

Oil to Single Refiner)• Collected 25 samples with

proven damage and no damage

• Evaluate 8 industry vendors on up to 10 different NDT techniques (4-5 “Majors”, 2-3 “Boutique” NDT Service Providers)

• NDT Round began this in Feb 2013 and completed in Sept 2013


Old API 941 Recommended Methods

Backscatter Techniques

Velocity Ratio

Attenuation

Spectral Analysis Amplitude

Pattern Recognitio

n

Spatial Averaging

Directional Dependen

ce

Frequency Dependen

ce

Conventional Shear

Wave

High Frequency Shear Wave

Angle Beam

Spectral Analysis

Highlyunreliabl

e

Yes: Works but

not for scanning

Broadly works but not

forscannin

g

UnreliableBroadly

works but not reliable

UnreliableBroadly

works but not reliable

Broadly works but

not forscanning

Not reliable Not reliable

Not reliable


The Ugly: Multiple Vendors/Techniques

V 1V 2V 3V 4V 5V 6V 7V 8V 9

V 10


¼” each Macro etch Both Sides

Macro Name

# of NDT Hits

Macro Damage Y/N/M

Mount #

PF3-A 0 Y Big 3" Mount

PF3-B 0 N Big 3" Mount

PF3-1 1 N-2 3 M PF3-2-1-3 3 N-4 4 N PF3-4-2-5 4 M PF3-5-3-6 3 N

A 12 34 56 B

Each Color represents Different Vendor confirmed “Hit”

Oval and Rectangle represent 2 different Interns “Interoperation” of Location per

Report

THE UGLY: Variable Results/Same Sample

None of Vendor-Called areas had damage. Area A and B (with Star) called “clean” but all had 40% HTHA Attack


THE UGLY: SUMMARY

• Over 600 areas of multiple “calls” form multiple vendors and techniques identified

• 150 samples examined under Microscope• 1 positive Confirmation-149 No Damage

It gets worse• 2” through wall crack missed by 5 of 6 vendors

(near Flange hub)• Two “Good” areas by all vendors had 40-50%

attack



US Chem Safety Board Recommendation

With no viable NDE Method to insure Integrity, each refinery was looking at replacement costs of $50-150 Million per Hydrogen Unit (some have 2-10 Units)

The Good: Practical approach-what works

• Regrouped with an NDE Training (not Service provider or OEM) and Academic to review what went wrong with trials

• Tried different Modalities and methods on samples from Round Robin

• Review typical damage found and missed• Practiced in shop and took it to use in field-like

conditions on Ex-Service Exchangers


The Good: Dissected Exchanger with HTHA

Can 3


The Good: NDE on Ex-Service Exchangers


Extract Damage for Testing and Training

Exchanger TB LW3


Typical Exam example and report format


Importance of Technician Training

Soon-to-be API RP 941 guidance regarding state-of-the-art NDE (TOFD, PAUT, FMC/TFM): “These techniques, procedures, and operator proficiency should be

demonstrated on a broad spectrum of HTHA damaged samples (including both damage degree and damage areas, i.e., welds and base metal).

Be aware that individuals receive thorough training, not companiesMake sure the technician working in your refinery received training.

Up to 50% of students in PDI effort for HTHA inspectors may fail the training test in any given class.Students are typically experienced and familiar with the inspection

equipmentThis emphasizes difficulty of HTHA inspections with ultrasonic testing

Performance Demonstration Initiative (PDI) for HTHA


Some Dated StatisticsTechnician StatisticsTotal number of Techs Examined: 96Number of Initial Pass: 64Number of Initial Failures: 32Number of Retraining Pass: 12

Exam statisticsAcquisition = 3 samplesAnalysis = 6 data filesTotal: 9 elements per examNumber of total exams: 96Total number of elements 864Percentage Passed: 92.5%Percentage Failed: 7.5%

Broadly equal pass/fail between acquisition and analysis


SummaryPrerequisite:

All students are expected to be proficient at TOFD and PAUTNot all students were, despite holding respective level 2 certificationTwo students were incapable of performing TOFD despite holding level 2

certificationPrevious HTHA Experience:

Some students have had extensive experience inspecting for HTHAPrevious HTHA experience has not shown to be markedly beneficial

Reasons for failure:Common reasons for failure were falsely calling material inclusions HTHASome students failed from missing HTHA that had coalesced into large

cracks16 students failed data acquisition (this included analysis of their own

data)23 students failed data analysis exam (6 separate data files)

NDTMA 2020 Annual Conference


Thank you for your participation in the NDTMA 2020 Annual Conference

Michael Nugent [email protected] 212 233 2737C 201 446 0212www.lpiny.com

http://lpiny.com

http://www.lpiny.com/

Documents

NDE for High-Temperature Hydrogen Attack (HTHA): A Joint