where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

656 views
Technical Discussions
Eko Sugiharto
NDT Inspector
PT. Pupuk Sriwidjaja, Indonesia, Joined Jun 2001, 1

Eko Sugiharto

NDT Inspector
PT. Pupuk Sriwidjaja,
Indonesia,
Joined Jun 2001
1
01:52 Jun-13-2001
hygdrogen embrittlement

I (My company) have a problem with hydrogen embrittlement at BFW-Synthesis ammonia exchanger, and I need newest information about Nelson curve. Please give me some information about it.

Best regards
eko


    
 
 
Chris Jones
Chris Jones
01:09 Jun-14-2001
Re: hygdrogen embrittlement
Eko,

My name is Chris Jones of Materials Performance Technologies (www.matperf.com). I have been involved with ultrasonic examination of three ammonia plants and one oil refinery for inspections for high temperature hydrogen attack. I have found hydrogen damage to varying severity levels in one HT shift vessel, two LT shift vessels, converter areas, two methanators, 1 secondary reformer and even mild damage in 1 desulphurising unit of an ammonia plant.

I have found extensive damage in associated pipe work in these plants. I have found the damage in parent material, weld metal and heat affected zone regions. I have found damage in forgings and in heat affected zones of weld repairs in cast elbows.

In all cases the pressure equipment had the potential for hydrogen embrittlement according to the most recent Nelson curves of API941 and the material of construction was in all cases carbon half molybdenum grade materials. The reason for the relatively recent known susceptibility to hydrogen damage was associated with awareness provided by the recent changes to the Nelson curves in relation to carbon half molybdenum material 1997 - API941.

The ultrasonic methods I employ (backscatter and a combination of velocity ratio and attenuation testing methods) are suitable for detection of hydrogen damage and in many situations I can provide an indication of the severity of the damage. The problem I find with procedures that I have developed which attempt to classify damage is that hydrogen damage occurs differently for different materials. Factors such as steel cleanliness dictate how damage will manifest in various materials.

I have published at the International Conference on Pressure Vessel Technoliogies (ICPVT 9) and soon intend to publish again devulging many of the things I have learnt since my original encounters with HTHA.

If you are intending to undertake inspection I can provide advice on where to look and how to look for the damage.

Regards,
CHris Jones.

: I (My company) have a problem with hydrogen embrittlement at BFW-Synthesis ammonia exchanger, and I need newest information about Nelson curve. Please give me some information about it.
.
: Best regards
: eko
.



    
 
 
John O'Brien
Consultant, -
Chevron ETC , USA, Joined Jan 2000, 278

John O'Brien

Consultant, -
Chevron ETC ,
USA,
Joined Jan 2000
278
02:17 Jun-14-2001
Re: hygdrogen embrittlement
API 941 publishes the Nelson Curves and the expected susceptability to Hydrogen Damage. You should be consucting a rsik assessment based on materials, tempertures and partial pressure to determine possible susceptability.

Different operators report slight variations in experience with when HTHA attack occurs. Some prioritise Risk 1 above the C 1/2 Mo Curve and Risk 2 those withn 50 Degrees F of the C 1/2 Mo Curve.

There has been a recent roundtable discussion at the Sprin API Refining Meeting on HTHA and the various NDT approaches to looking for and assessing it.

Most people are using some form of Velocity Measurement and Backscatter Technique.

The number one issue is you need experienced personnle or you need to train people to do this type of work to get good results.



    
 
 
Brian Shannon
Brian Shannon
01:57 Jun-15-2001
Re: hygdrogen embrittlement
: Sir: The evaluation of Ammonia plant equipment for high temperature hydrogen attack and other mechanisms is comprehensively documented in a publication from last years AICHE Ammonia Safety symposiun. The paper(Written by G.R. Prescott / Brian Shannon) describes the parameters for the degradation and covers the latest in its detection and assessment techniques.The content on field inspections covers experience from over 250 Ammonia and Refining plants worldwide. Please refer to our web page for details on this and other field services that are available from IESCO .


    
 
 

Product Spotlight

FlexoFORM™

The FlexoFORM™ solution integrates flexible phased array probe technology in a scanner to solv
...
e the challenges that come with inspecting pipe elbows. When combined with a water column, this solution can be used to collect easy-to-interpret data on elbows with diameters ranging from 4.5 in. OD up to flat and offers many benefits.
>

EKOSCAN Phased Array

In order to always fit your needs, EKOSCAN can manufacture any type of UT transducer, either convent
...
ional or Phased Array. As an ISO 9001: 2015 certified company, EKOSCAN is extremely careful as far a material selection and manufacturing processes are concerned. Our probes guarantee our customers the benefits of latest innovations regarding piezo-composite, backing, impedance adaptation layer, etc. Specific probes for hostile environment: high temperature, high pressure, corrosive environment,etc. Specific probes designed to fit your specific application: optimization of every parameter to guarantee you the best detection.
>

Research Center IDEKO develops an ultrasonic train wheel inspection system for CAF

The Basque Research centre IK4-IDEKO has developed a state-of-the-art ultrasonic inspection system f
...
or the train wheel. This system secures a sound condition of train wheels and is thus a significant contribution to rail transport safety. The device was delivered to CAF recently and its use allows the manufacturer to become an approved supplier of rolling stock in Italy, as it meets the demanding homologation standards of this country. \\\\r\\\\n
>

Teletest Focus+

Teletest Focus+ electronics have superior capabilities than rivals on the market. Beyond the usual
...
test features, Focus+ has 24 transmit channels and 24 receive channels, with an additional on-board switching capabilities. The instrument's frequency range is 10–300 kHz.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window