×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Check pH in TEG

Check pH in TEG

Check pH in TEG

(OP)
Hi ALL,

our gas processing has TEG generation system that required to check pH in lean TEG weekly.
the procedure to test pH of lean TEG as below:
PROCEDURE
4.3.1 Calibrate the meter, using the buffer solutions, in accordance with the manufacturer's
instruction manual.
4.3.2 Measure 11 ml of glycol sample and 239 ml distilled water into a 250ml beaker. Mix
thoroughly.
4.3.3 Place pH electrode and thermometer into the solution.
4.3.4 Adjust temperature compensation control on pH meter to correspond to solution
temperature.
4.3.5 Read pH directly from meter scale and record.
4.3.6 Rinse electrodes with distilled water


I do not figure out why to add distilled water for the test. the man made procedure already has retired.
I would appreciate your advice on the master.
thanks all in advance!

RE: Check pH in TEG

Hi,
Let you check with your lab manager and/or request a 3rd party to perform the analysis.
My 2 cents
Pierre

RE: Check pH in TEG

I second pierreick,

WRT the water i guess its about measuring pH. I dont think that acids will dissociate (when the acid donate the proton like HCL <=> H+ + Cl- )in TEG so you need to add water to be able to measure the pH. But its been too long since i did chemictry in a lab so i dont recall this part.

--- Best regards, Morten Andersen

RE: Check pH in TEG

What is the pass/fail criteria? What is your production pH requirement?

I can see doing something like this to check for contaminants or consistency in the TEG process.

see https://assets.fishersci.com/TFS-Assets/LSG/Applic... for a possible explanation for diluting the sample.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Check pH in TEG

So the text IRstuff refers to give 5 reasons, the first three being someting to do with the measuring principle and the last one the reason i gave. In the case with TEG i think its 4) and/or 5) but im not sure.

--- Best regards, Morten Andersen

RE: Check pH in TEG

(OP)
Thanks all for your comments/advice.
I also wonder about volume TEG (11ml)and distilled water (239ml). where do numbers come from? or related to ASTM?
thanks again

RE: Check pH in TEG

probably not since its in ml =250 ml. ASTM would have chosen something in fl oz i would guess. 250 ml is most likely just because is a normal type of beaker. The ratio water/sample is to achieve the correct dillution to be able to measure pH.

--- Best regards, Morten Andersen

RE: Check pH in TEG

Who is manufacturer of this meter, and what type electrode is this? Have you asked the meter manufacturer?
Literature from BS&B for a Ag/AgCl electrode requires a 1:1 v/v dilution of the lean glycol sample with de ionised water, while you have stated a 1:22 v/v. dilution.

RE: Check pH in TEG

(OP)
Thanks ALL for your advice.
actual the problem is normally pH of lean TEG in our system is about 7.3 and it has maintained for longtime (about 20 years) but recently we found it drops to 6.0
then I look back to procedure to test pH in TEG as showed diluted with distilled water in strange ratio (TEG/distilled water: 11/239)
Now we are attempting to refresh TEG in the treatment system.
other my concern is the solubility of H2S in TEG to cause low pH?
thank you!

RE: Check pH in TEG

pH of 6 for a 50% solution of glycol in water is considered acceptable for new TEG.
See this doc on pages I16 to I19 for relevant details re interference of H2S on Karl Fischer titration for manual test for water content of TEG.

https://pacs.ou.edu/media/filer_public/54/44/5444c...

RE: Check pH in TEG

Hi,
Weird answer from last poster. AI?
Meaningless.
Pierre

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close