8 replies to this topic

[Anshul619]

Dear all,

 

 

I was going through my revision of sizing of absorber column when one of my friends asked me a very pecular question....

 

The question was that how do we specify the SAMPLE CONNECTION in absorber column????

 

I was dumbfounded and was not able to even understand his question.

 

If we put the sample connection, will there be any problems faced by it???

 

And if we make a SAMPLE CONNECTION how do we make use of it i.e., how do we collect the sample from a in-service absorber column.......

 

My friend is currently commissioning the Amine Sweetening Unit.....

It was his query but I am not also able to understand this concept...................

 

Please help......

[Dacs]

When you get to operate a column (in your case, an amine column), you'd want to monitor its performance over time.

 

For amine systems, taking a sample on a regular basis serves as a method to check the quality of amine, as well as foaming tendencies (which ultimately relates to how your column operates).

 

In this case, you'd want to install a sampling point, whether it's on the column or on its piping, to draw out a sample for laboratory testing.

 

My experience leans towards placing an in-line sampling point on the piping from the column bottom. It's normally placed in a piping where pressure drop exists (such as control valves) to facilitate flow of the sample to the sampling bottle.

 

The configuration of the sampling facility depends on what you want to sample, and how hot the source fluid is. With that I can't answer any particular configuration without knowing more details of the system in question.

[Anshul619]

Dacs,

 

Thank you sir for your swift reply....

 

I do not have the process specifications for this column....

 

But lets assume for arguments sake we have to make the sample point on column not in piping..

 

How do we decide where does this SAMPLE CONNECTION is placed...???

[thorium90]

You would put sample connections where you want to take samples from. The samples you want to take depend on what you want to monitor. For example, concentration of the lean amine to the absorber. Do you foresee the need to monitor a certain parameter to monitor the performance of the unit? If you need to, then place a sampling point at a location where one can grab a representative sample.

 

As for the configuration, as Dacs has replied, it would depend on the properties of the fluid being sampled. For example, if one was sampling the conductivity of superheated steam, one would need to cool it down and condense it before measurement.

Edited by thorium90, 29 April 2013 - 03:15 AM.

[Anshul619]

You would put sample connections where you want to take samples from. The samples you want to take depend on what you want to monitor. For example, concentration of the lean amine to the absorber. Do you foresee the need to monitor a certain parameter to monitor the performance of the unit? If you need to, then place a sampling point at a location where one can grab a representative sample.

 

As for the configuration, as Dacs has replied, it would depend on the properties of the fluid being sampled. For example, if one was sampling the conductivity of superheated steam, one would need to cool it down and condense it before measurement.

 

Thorium90,

 

Thanks for reply.

 

I understood your explanation........

 

And then to sum this topic up final questions,

 

Is there any specification which entails the sizing of this SAMPLE CONNECTION??

 

And please bear with me..... How is this SAMPLE CONNECTION works in the column.....I mean how do we extract the sample???? Is there any process involved or just press the button and get the sample in the container or sample box???????

 

Thanks

[neel_avi]

Dear Mr. Anshul, 

 

1. I fail to remember any of the refinery units that I have worked for, where sample connections are directly from the column with an extra nozzle at an extra cost only for sampling.

 

For atypical LPG treatment equipment like extractor-Plus of UOP, intermediate sampling of LPG for excess H2S is provided, but sample points are still typically on outlet piping.

 

Caustic tanks or large storage capacity vessels, where mixing of two liquids of considerable density difference is achieved may be provided with intermediate nozzles for sampling, to ensure homogeneous mixing and to identify layer formation.

 

2. If you are consulting with a firm or you yourself work for the firm, in either case there will be indigenous standards for sample connections. Thats what I have been seeing till date. And configuration of sample connection is as told by the two experts earlier based on the service conditions and safety.  

 

3. I interpret the 'press the button' part as 'open the valve'. Sample connections are simple in nature and preferably manual, other than if it has got any statutory requirement, like water treatment automatic samplers or ambient air monitoring samplers. I believe its better to invest in areas of the units which are more critical rather than on automated sample connections (isolation however for the sample connections needs to be reviewed critically). I would rather, develop SOPs for safe and proper sampling with a simple sampling unit. 

 

Hope I was able to share my views.

 

Regards

 

Avijit

[ankur2061]

Anshul,

 

Some guidelines for where and when to sample (sampling frequency) for glycol & amine units can be found in the following link. I had raised the query and subsequent to that I had prepared a 50 page sampling standard for an upstream / midstream O&G company. This standard included sampling procedures as well as process schematics with detailed explanation for sampling of toxic / flammable /  volatile / non-toxic / non-volatile liquids and gases. The sampling systems described were both automatic sampling systems as well as manual sampling systems.

 

http://www.cheresour...reatment-units/

 

Regards,

Ankur.

[Anshul619]

Dear Mr. Anshul, 

 

1. I fail to remember any of the refinery units that I have worked for, where sample connections are directly from the column with an extra nozzle at an extra cost only for sampling.

 

For atypical LPG treatment equipment like extractor-Plus of UOP, intermediate sampling of LPG for excess H2S is provided, but sample points are still typically on outlet piping.

 

Caustic tanks or large storage capacity vessels, where mixing of two liquids of considerable density difference is achieved may be provided with intermediate nozzles for sampling, to ensure homogeneous mixing and to identify layer formation.

 

2. If you are consulting with a firm or you yourself work for the firm, in either case there will be indigenous standards for sample connections. Thats what I have been seeing till date. And configuration of sample connection is as told by the two experts earlier based on the service conditions and safety.  

 

3. I interpret the 'press the button' part as 'open the valve'. Sample connections are simple in nature and preferably manual, other than if it has got any statutory requirement, like water treatment automatic samplers or ambient air monitoring samplers. I believe its better to invest in areas of the units which are more critical rather than on automated sample connections (isolation however for the sample connections needs to be reviewed critically). I would rather, develop SOPs for safe and proper sampling with a simple sampling unit. 

 

Hope I was able to share my views.

 

Regards

 

Avijit

Avijit,

 

Thank you for your reply..

 

I have understood your point of view regarding Sample connection in the outlet piping.

 

But pleas tell me if my below statement stands correct:

 

"For SAMPLE CONNECTION,this point is generally manual/auto valve through which we can extract the sample.

And this practice is more desirable than CONNECTION on the column itself;due to the high costs.

But if we want to give CONNECTION on column then we can give the CONNECTION at the level of fluid(we want to SAMPLE) regardless of the orientation of the nozzle(SAMPLE CONNECTION)"

 

Right?????

[Anshul619]

Anshul,

 

Some guidelines for where and when to sample (sampling frequency) for glycol & amine units can be found in the following link. I had raised the query and subsequent to that I had prepared a 50 page sampling standard for an upstream / midstream O&G company. This standard included sampling procedures as well as process schematics with detailed explanation for sampling of toxic / flammable /  volatile / non-toxic / non-volatile liquids and gases. The sampling systems described were both automatic sampling systems as well as manual sampling systems.

 

http://www.cheresour...reatment-units/

 

Regards,

Ankur.

 

 

Ankur,

 

Thank you sir for this information.

But I cannot find your 50-page book on the SAMPLE CONNECTION...

 

Please direct me there sir.

 

And Thank you in Advance for book.....!!

 

And pleas comment on my STATEMENT below:

 

"For SAMPLE CONNECTION,this point is generally manual/auto valve through which we can extract the sample.

And this practice is more desirable than CONNECTION on the column itself;due to the high costs.

But if we want to give CONNECTION on column then we can give the CONNECTION at the level of fluid(we want to SAMPLE) regardless of the orientation of the nozzle(SAMPLE CONNECTION)"

 

Right?????

Edited by Anshul619, 29 April 2013 - 10:51 PM.