Mass Balance or Energy Balance?

Thermodynamics stipulates conservation of mass, so use Mass Balance.

Do both.

Convert 5000 barrels to pounds. You can do this if you know the density of the condensate. Divide the pounds of condensate by the molecular weight (you know the mol weight as you know the composition of the condensate). Once you have the lb-moles of the condensate, you can multiply this by 379 to get the equivalent in standard cubic feet of gas at standard conditions (14.7 psia and 60 deg F). Once you have this standard volume convert it to the actual operating pressure and temperature using the gas law. The operating conditions must be such as to keep the fluid in vapor state.

I must be interpreting this question incorrectly, because it seems to be nearly impossible to solve to me. For the 11 years I worked in the oil and gas fields of NW Pennsylvania and W. New York, the condensate from gas lines was a combination of water that was produced from the well with the natural gas (water vapor) and other hydrates of hydrocarbons from the well. To relate condensate to volume of gas would require an in depth study into the original water and hydrate content of the gas input into the system. Assuming various sources of the natural gas (different fields), this becomes a very complicated mathematical problem.

thanks phys

well i get a dry gas from POD , the condensate is generated enroute. my collection point is about 100km away from POD.

I HAVE the analysis of both condensate and natural gas.. how to calculate un-accounted for gas from POD to my end point as i get natural gas as input and i have two outputs condensate and natural gas....plz reply

I really am not the person to help you on this, as I was a well (gas or oil reservoir) analyst, not a gas transmission analyst. Everyone I knew in the transmission side of the industry back then (20+ years ago) are out of touch or dead, so I can't even suggest a contact to help you. I do know that your condensate is most likely coming from your "dry" gas, as there is no such thing as perfectly dry gas. I still think there are too many variables to account for to do this. Condensate out should be able to be related to gas in, if you can cool a portion of the incoming gas enough to condense and see how much condensate is actually generated. But I see some potential condensate going with the gas at the usage points, leaving us with no way to conclude anything from the output at the 100KM terminus.

Apparently the dynamics of your gas transmission is akin to the same principles as of a Cooler Condenser. So I suggest that you look to Cooler Condenser Design methods for the analysis. That should work for you. refer to your Handbook of Chemical Engineers, and then look for the applicable equations.

Dear Editor

Thanks for the reply and thanks to phys......

i think we/I have reached a DEAD-END. where now the answers and help seems to be stopped shortly.

can you please give me some documents/ equations or methodology for the conversion?

Regards

Naushad

I take it from your request that you do not have Perry's Handbook of chemical Engineers which I had referenced earlier. I do not have access to my books so I am not able to get you the equations.

However, I can refer you to alternative books for the same equations. First for simple process equipment design equations, you may look for the book, Mass Transfer Operations by Treybal published by McGraw-Hill; Second for more sophisticated analysis you may look for the book, by Frank Kamanetskii, with a title that includes "Diffusion [something]" I have not had the need to read this book for very many years, so finding this book may take some work for you.

So summarizing there are two main references:

1. Mass Transfer Operations by Treybal
2. Handbook of Chemical Engineers - Perrys
   

Goodluck.

I've been doing this for 35 years. You do both the heat (BTU) and the volumetric balances. Then look at both ways. If the BTU and Volume gains/loss are the same percent wise, you have good balancing system. If the two are different, then 90% of the time the BTU content measurements or assumptions are wrong.

Next, plot the two balances overtime and use SPC to see if the system is stable then work on improvements.

You can account for water in the system too. Water has volume and no BTU content (actually it does have 50 BTU/cf UHV, but that's another issue).

Your Mightyness,

It does not matter that you have told him to use some cryptic method, as he can not use it perhaps because he is no familiar with it or because you are explicit about the method.

However, the Cooler-Condenser design/analysis method is explicit enough for him to follow to evaluate the quantities of condensate and gas flowing in and out as well as the BTU changes. Then and only then can he get to the suggestions you are making. In fact implicit in the Cooler-Condenser analysis approach are both the Mass and Energy Balances Analyses he was curious about to start with.