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Ethyl Mercaptan Dosing Rate Calculation

lpg ethyl mercaptan odorant

6 replies to this topic
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#1 chemilocha

chemilocha

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Posted 16 October 2019 - 08:28 AM

Dear All,

Guys we are going to operate LPG offloading terminal. I need some reference/sample odorant dosing calculation.

Total LPG flow rate is 224 m3/hr (7 pump working , each pump- 32 m3/hr)

now, i would like to calculate the ethyl mercaptan dosing rate to the LPG flow line @ 15 PPM

can anybody provide me sample calculations or any reference code or standards followed in the oil and gas industry.

Thanks.

#2 Bobby Strain

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Posted 16 October 2019 - 09:17 AM

It's simple arithmetic.

#3 breizh

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Posted 16 October 2019 - 06:17 PM

Hi ,

Should be easy if you define PPM volume or PPM mass !

volume or (mass mercaptan) / volume or (mass LPG) = 15 e-06

mass = volume *density

hope this is helping you

Breizh

#4 N243

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Posted 17 October 2019 - 04:25 AM   Best Answer

Hi Chemilocha,

It is indeed simple arithmetic. I can demonstrate below :

Assumptions:

1. Operating flowrate of LPG is taken as 224 m³/hr

2. PPM is expressed in volumetric basis.

Calculation :

• 15 PPM of Ethyl Mercaptan is the same as 15 mg of Ethyl Mercaptan/ 1 Liter of LPG.
• Now, LPG flowrate of 224 m³/hr equates to 224000 liters/hr.
• Multiplying 224,000 Liters/Hour with 15 mg/ liter = 3,360,000 mg of Ethyl Mercaptan required per hour.
• Answer = 3.36 kg/hr of Ethyl Mercaptan required

I hope this clears up any confusion.

Kind Regards,

N243

#5 breizh

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Posted 17 October 2019 - 05:15 AM

N243,

Very confusing your calculation !  Either it's PPM volume or PPM mass .

note : 1 PPM volume = 1ml ethyl mercaptan per m3 LPG

if PPM volume , the answer is 3.36 liters /hour of Ethyl mercaptan for 224 m3/h of LPG

Breizh

Edited by breizh, 17 October 2019 - 05:27 AM.

#6 chemilocha

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Posted 18 October 2019 - 10:05 AM

Dear All,

thanks for your valuable response to the query.

Mr Bobby , yeah its simple arithmetic calculations but i want to verify my calculations with forum members.

Mr breizh , appreciate your answer. its matching with my calculations  too , 3.36 Litres/hour .  :thumbsup:

Now Suppose, if i want to calculate in terms of mass PPM, Considering LPG  density - 530 kg/m3

then  the required ethyl mercaptan at 15 PPM  will be 1.7808 kg/hr ??

regards,

chemilocha

#7 breizh

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Posted 18 October 2019 - 10:33 AM

Hi ,

Yes 1.7808 kg/h . Considering a density of 860 kg/m3 for E.M the flow rate should be about 2.07 l/h .

Breizh