TM0284 - HiC test procedural questions 1

[tm0284]

I am in charge of setting up our facility to do HiC testing. We haven't done the test in over 7 years at my company and most of the equipment left over is unusable. Also many parts of the old procedure are no longer acceptable to our new safety team. I had a few questions and was wondering if someone with experience doing the test could help me out with a few items. Here is a diagram of the current setup, it is very basic and uses a 3 gallon flask to hold the test solution, a desiccator to hold the samples and perform the test, a smaller flask for a gas trap, and another small flask with NaOH to filter H2S exhaust.

First on the list is equipment. We currently use a desiccator with a rubber stopper with holes drilled in it in which lines are inserted. Does anyone have an example of a better setup that would be easy to build or one that we could order already assembled? I would like a method to be able to add or remove test solution from the vessle without having to remove the top or allow any H2S to escape. I was thinking some type of specially made syringe should do the trick.

Second, what is a good way to measure the pH at the start of the test after H2S saturation. Is there a safe and easy way to do this without allowing oxygen to enter the vessel?

Third, The first two times the test was ran the solution became extremely black and cloudy after apoximately 50-60 hours of test time. Is this normal? If not would oxygen contamination cause this or is some other type of problem occuring?

Fourth, Any general advice and tips would be appreciated!

Thanks for taking the time to read this, hope to hear from you soon.

 

[EdStainless]

Since you didn't ask I will presume that you have addressed the explosion risk, as well as H2S sensors and alarms.

I am in the same position as you, I haven't done these in a long time.
We did it in a separate building with a blast wall.
We had block and bleed valves on everything with Nitrogen purge.
We ended up sending all of this work out.

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Plymouth Tube

 

[tm0284]

Yes, we have installed wall mounted h2s sensors and have handheld ones for all personal. Explosion risk is also been taken into account and steps taken to avoid such a scenario. We have all the tubing installed with valves just fine. The problem is the actual test vessel itself where the samples sit. Determining pH of the test solution after h2s saturation without allowing oxygen to enter or h2s to escape is the biggest challenge currently left to overcome.

Also I'm not sure why the pictures are not showing up in my post, I will try to get that fixed.

 

[cloa]

Best to upload your files to Enginering.com in the link at the bottom of Reply to this Thread

http://www.eng-tips.com/threadminder.cfm?pid=1529

Use translation assistance for Engineers forum

Note the rules include No Student posting

 

[tm0284]

Ah, I see. Missed that link the first time. Here is a simple drawing of the setup we have thus far.

 

[tm0284]

Sorry, messed up on the previous post. I see no way to edit posts so trying this again.

 

[CoryPad]

Cortest (

http://cortest.com/index.htm)

is one company supplying equipment to conduct these types of tests.

Here are some images of one testing lab's HIC setup:

http://www.omnimetalslab.com/index.php?option=com_content&view=article&id=65&Itemid=41

I have never seen the pH measured after introduction of H[sub]2[/sub]S but before the end of test/nitrogen purge. My experience was pH measured on solution, fill test cells, seal cells, introduce H[sub]2[/sub]S, wait for required duration, purge cell, open cell, measure final pH, remove specimens.

The solution turning black and cloudy is expected.