Emerson Exchange 365

Hello Zeeshan,

The FB103 does take into account wet gas, but it only in regards to the heating value (and therefore Energy totals). Understand that Energy = Volume * Heating Value, or Energy = Mass * Heating Value, depending on which heating value basis you select (BTU/lb or BTU/ft3). We do not take wet gas into account when performing volumetric calculations.

And even then, this only applies when you select to “Calculate” the heating value. If you select to “Enter” the heating value, it will be used directly, as-is, with no wet gas adjustment.

When you select “Wet” as the option, and you have a mole percent of water of 0.0, you’re enabling a “wet gas” calculation of sorts. You’re asking the program to determine a percentage of water based on some of the other inputs, and use that percentage when determining the heating value, which then goes into determining the energy flowrate. The volume flowrate really shouldn’t change, as you switch between “Wet” and “Dry” heating value options. If there is a mole percentage of water entered (non-zero), then this feature is not enabled, and the composition as entered will be used to determine the heating value.

For a set of fixed inputs, if you select to calculate the heating value on a “Dry” basis, you should get a larger heating value, and therefore a larger energy flowrate, then you will when you select the “Wet” basis option with this feature. That is because the “Wet” basis option will take into account the theoretical amount of water in to natural gas (which cannot be combusted, and does not provide energy).

In summary, this wet gas correction feature could be useful, if the gas is being bought and sold based on its energy content. We have a way to correct the energy rate and totals for wet gas, but it doesn’t correct the volume.

If you need further explanation, please submit a SupportNet ticket at:

w3staging.emersonprocess.com/.../login.html

Best regards,

Nick Norenberg
RAS Tech Support, Global Lead
7-Sept-2016