10 H. Static Pressure Due to Elevation Change, Equations 10.49 and 10.50 Back to Main
This
page is used to determine the static pressure due to elevation changes in the
line. In actual practice the line may
be going uphill or downhill causing a change in potential energy affecting and
. Since the gas is compressible and the
temperature varies, many models may be used, but the simplest equation is
(10.49)
Where: H =
head
= gas relative density
= mean gas temperature
= mean gas compressibility
= pressure at bottom of static column
= pressure at top of static column
A = constant
Equation
(10.49) also can be written in the form
(10.50)
Where:
To
calculate the static pressure due to elevation changes the Gas relative
density, Average gas compressibility factor, Wellhead pressure ,
Elevation change, and Average gas temperature must be entered into their entry
space. To do so use the mouse to click the courser in the entry spaces and
input the data. Once this has been done, select Run to execute the solution. For more information, please refer to Example 10.9 in the book Gas
Processing and Conditioning Volume 1.
Gas
relative density is the density of the gas divided by the density of air or the
molecular weight of the gas divided by the molecular weight of air at
atmospheric pressure.
(1.2)
Average
gas compressibility factor is the measurement of how much the gas at a given
temperature and pressure deviates from ideal-gas behavior. This is the same as the mean gas
compressibility.
Wellhead
pressure is the
pressure at the top of the static column.
Elevation
change is the pipe length in the vertical direction from beginning to end.
Y
= elevation change
L
Y
X
Since
the gas is compressible, the temperature varies. In this equation, an average temperature is used. The average
temperature is also termed as the mean temperature.