10 replies to this topic

[wafasaleem]

Hi friends,

 

This query is just for educational purpose. Suppose a natural gas processing plant consisting of sweetening(amine), dehydration(JT) and sulfur recovery(Claus) units are designed for a turndown capacity of 40% feed gas. During the course of gas extraction, the pressure and flowrate of the raw gas gradually decreases and at some point reaches the design turndown value. what should be the changes and troubleshooting to be done for the plant if the gas feed rate is below the design turndown?

 

Regards

[Napo]

Wafasaleem,


You need to install some recirculation lines for to have the operatives parameters of production (quality), you need a low pressure system for to have recircualtion system permit the plant operation specially if the charge is variable.

I attached you a simplified configuration of our plant.

Napo.

Attached Files

•  Overview Gas Plant.pdf   23.26KB   69 downloads

[wafasaleem]

Thanks

But is there any way of reducing the turndown ration to say 20-25 % ?

[Napo]

Wafasaleem,

 

With this configuration our plant Works between 110% and 10% of the charge, obviously you need other design parameters.

 

Napo.

[wafasaleem]

But this is a different process from what I have mentioned in my topic.

[Napo]

Wafasaleem,

I gave you only a "real application" about your "educational purpose", then you can put more or less units and work under this scope if you want.

Maybe other colleagues will give other "solutions" about your question.


Napo.

[Root]

once you are going to reduce the load on plant you need to consider following points,

1. Heat medium duty.
2. cooling duty.
3. mostly rotating equipment are not recommended to operate below 30% of their design.
4. vessels level controlling.

Cheers

[wafasaleem]

Thanks root,

 

How do we manage the pumps and any rotating devices in such a situation?

[shan]

Recycle to meet your minimum flow requirements.

[wafasaleem]

Recycle to meet your minimum flow requirements.

 

Sorry, but could you make it clear? what is to be recycled?
 

[Pronab]

In a real case of a gas processing plant, turn down case is 30 to 33%. Maximum throughput is 110%. This is valid for most of the gas sweetening, Gas dehydration and Sulfur recovery plant. 10% turn down as Napo told is quiet difficult to operate a plant. What you describe in your query, it contains fractionation Column, Pumps, Compressors etc. For rotating equipements you my have recycle, but for static equipments should have a minimum hydualic balance, else they will not work or poor performance. I will suggest to go for a specific case by case instead of getting general idea. Reducing turndown to 20-25% need modification of major equipements.

Edited by pronab, 16 April 2017 - 01:37 PM.