|
For liquified petroleum gas (LPG) flow calculation it is important
for given mixture composition determine all properties of LPG.
LPG is mixture of several components, but this calculator is made
as LPG is mixture of only two - propane and butane. Also it can
be used for clear propane or clear butane gas.
If volume of each component is known, than its volume ratio can be
calculated as follows:
where is:
ri - volume ratio of component i
Vi - volume of component i
Vmix - volume of mixture
n - total number of components
For known mass ratio, volume ratio of each component is calculated:
or:
where is:
ri - volume ratio of component i
gi - mass ratio of component i
Mi - molar mass of component i view table
Mmix - molar mass of mixture
n - total number of components
If mass of each component in mixture is given, than mass ratio can be
calculated as:
where is:
gi - mass ratio of component i
mi - mass of component i
mmix - mass of mixture
n - total number of components
For known volume ratio, mass ratio of each component is calculated:
or:
ri - volume ratio of component i
gi - mass ratio of component i
Mi - molar mass of component i view table
Mmix - molar mass of mixture
n - total number of components
When volume and mass ratio are calculated mixture properties can
be calculated as follows. For density (rho) it is:
or:
For molar mass (M) it is:
or:
For gas constant (R) it is:
or:
For partial pressure (p) it is:
or:
where is:
rhoi - density of component i view table
rhomix - density of mixture
Mi - molar mass of component i view table
Mmix - molar mass of mixture
Ri - gas constant of component i view table
Rmix - gas constant of mixture
pi - partial pressure of component i
pmix - pressure of mixture
Density of each component when LPG is in gas state is calculated as:
where is:
Z - compressibility factor
T - temperature of gas
Compressibility factor is calculated using Berthelot equation:
where is:
pr - reduced pressure
Tr - reduced temperature,
which are calculated as follows:
where is:
pc - critical pressure (for butane pc=34.9 bar and for propane pc=42.6 bar)
Tr - critical temperature (for butane Tc=425.8 K and for propane Tc=369.8 K)
Relation between mass and volumetric flow is defined by:
When LPG liquid phase is considered used formula is:
or for gas state:
where subscript 'nor' - is for normal state (p=101325 Pa, T=273,15K).
Real flow rate when gas state of LPG is calculated, can be
calculated as:
where is:
Q - volume gas flow rate at given pressure and temperature
rho - density of LPG gas at given pressure and temperature
Relation between velocity and diameter for liquid phase LPG can is calculated
using:
or for gas state LPG:
where is:
V - velocity
D - diameter
liq - liquid phase
gas - gas phase
Heat power for given flow rate is calculated as:
where is:
P - heat power
G - mass flow rate
HL - lower heat value
Lower heat value for LPG mixture is calculated as:
where is:
HLi - lower heat value of component i view table
Go to calculator.
|
