7 replies to this topic

[Wizgal]

Hi , currently i am working in one oil n gas company in Thailand (upstream) . Currently Glycol Dehydration system got problem. I have checked all of the parameters in the operation , everything is the same . Gas flow every two hour is 100 MMSCf . Before tht the system still can function well the moisture never exceed 7lb/MMscf but currently things turn up side down .Moisture cant be reduced to 7lb/MMscf . I have also check glycol quality with lab . Nothing is abnormally . Anyone know , are there any solution that i can do for this problem?.. I also have check all the leak point which its not exist.

[Art Montemayor]

Wizgal:

 

You don’t furnish all the information to get to the source of what you identify as a problem.

• First, confirm that your dewpoint measurements are correct.  Have you calibrated your DP meter?  Have you compared your readings with that of your client’s (or of the pipeline operator)?
• What dewpoint is your meter measuring? 
• How much moisture does your product gas contain?
• Next, confirm that your TEG pumps are working correctly and that the correct amount of TEG is being continuously circulated.
• Make sure that your stripping gas is flowing in at the correct flow rate and temperature.
• Confirm that your reboiler is maintained at 400 ^oF.

If the above all checks out well, then you are either not absorbing moisture in the contactor or you are not stripping out the moisture in the Stripper.  Which ever, it is can be due to a packing failure in the contactor (channeling, distributors bad, trays damaged, etc.).  This means that you have to bring the process down for cleanout, vessel entry, and inspection – all very costly and time consuming.

 

[Wizgal]

The dew point metering already calibrated. The reboiler temperature now maintained at 395 not more than 400 F . If the temperature is not stable does it effect to dew point?. I mean its not always stay at 395 sometime its go to 390 , 393 , 395 . If it possible that the packing inside contactor can be clogged?.. Previously this contactor use bubnle tray but then later on it change to structure packing . The maximum capacity for bubble tray is 100.5 MMscf of gas and the vendor said by usung structure packing the capacity can increased to 120 MMscfd by using the same contactor . Is it the matter that the contactor cant receive more gas flow ?.. Thank you very much for your answer , its really helpful.

[Wizgal]

The moisture in gas is 65 lb/MMscf

[Art Montemayor]

What about the rest of the questions:

• What dewpoint is your meter measuring?
• How much moisture does your product gas contain?
• Next, confirm that your TEG pumps are working correctly and that the correct amount of TEG is being continuously circulated.
• Make sure that your stripping gas is flowing in at the correct flow rate and temperature.

Is 65 lb/MMScf the value of moisture content in the PRODUCT gas - or in the raw feed gas?  Please be specific.  We waste a lot of time and effort in "guessing" or "speculating" what you mean to write.   Also confirm that your client or pipeline transporter verifies your product gas dew point readings.  You should be operating your reboiler at 400 ^oF unless your operating manual states otherwise.  If so, then how do you propose to produce product gas with only 7 lb of water/MMScf of product gas?   That is why the stripping gas conditions and flow rates are very important.

 

Await your detailed and specific responses.

[ahmed abd elmonem]

could you ensure please that the problem arise after increasing gas rate and/or replacing trays with structure packing?!

[Wizgal]

@Art Montemayor : We only measure the moisture of the gas,thus the dew point is not available in our platform. 65 lb/MMScf  is the value of water content in gas that feed to glycol contactor , we have to make it to 7 lb/MMSCf  for our customer. Right now the moisture content in gas exceed 7 lb/MMSCf so now we got penalty from our customer.  Sorry for making you wasting your time, I am still new engineer i am still lack of experience .

 

@ahmed abd elmonem: The problem occur after rising gas rate and in the past it's sometime happen after the structure packing has been installed. Currently it's always happen.The  mosisture content always exceed 7lb/MMSCF

[Art Montemayor]

Wizgal:

 

You still have not answered my questions.........

 

Therefore, I won't answer yours.