Open regulated valve and standard room valve, inflate methane
to system, and adjust the standard room pressure to ideal
pressure.
After get the ideal pressure and stable temperature, start the
data collection of the isothermal adsorption experiment program
Repeating Step 3 *5, until the end of experiment of last
pressure spot
VS- Coal sample volume, units of measurement (cm3);
P*- Balanced pressure, units of measurement (MPa);
P*- Initial pressure of reference cylinder, units of
measurement (MPa);
P*- Initial pressure of sample cylinder, units of measurement
(MPa);
T*- Balanced temperature, units of measurement (K);
T*- Initial temperature of reference cylinder, units of
measurement (K);
T*- Initial temperature of sample cylinder units of
measurement (K);
V*- System total volume units of measurement (cm3);
V*- Reference cylinder volume units of measurement
(cm3);
V*- Sample cylinder volume units of measurement
(cm3);
Z*- Gas compression factor under the balance condition,
dimensionless
Z*- Initial gas compression factor of reference cylinder,
dimensionless
Z*- Initial gas compression factor of sample cylinder,
dimensionless
After getting the coal sample volume, calculate the free
space volume of sample cylinder. Free Space Volume refers to
the sum of various volumes that coal particle space after the
coal sample put into the sample cylinder, micro-flow gap of
internal coal particle size, the remaining free space of
sample cylinder, and connection tube and internal space
volume. Calculation formulas of free space volume as follows:
Vf- Free space volume, unit of measurement (cm3)
V*- Total volume of sample cylinder, unit of measurement
(cm3);
Vs- Coal sample volume, unit of measurement (cm3);
Z*- sample cylinder initial gas compressed factor,
dimensionless
Calculation the absorption capacity of each pressure
spot
According to balance pressure and temperature of reference
cylinder and sample cylinder, calculate adsorption capacity
of different pressure spot Formulas as follows
PV=nZRT
P-Gas pressure, unit of measurement (MPa)
V- Gas volume, unit of measurement (cm3);
n- Gas mole number, unit of measurement (mol)
Z- Gas compressor factor, dimensionless
R- Molar gas constant, unit of measurement (U·mol*1·K*1)
T- Thermodynamic temperature unit of measurement (K)
Respectively obtain the gas mole number of inner sample
cylinder before pressure spot balance and after balance,
the gas mole number of sample cylinder (N2), mole number of
coal sample adsorption of gas (ni)
Ni=n*-n2
ni- Gas mole number, unit of measurement (mol)
N*- Sample cylinder‘s gas mole quantity after balance, unit
of measurement (mol).
N*- Sample cylinder‘s gas mole quantity after balance,,
unit of measurement (mol).
Adsorption gas volume of each pressure spot
VI=ni * *2.4 * ***0
The gas volume of each pressure spot adsorption:
V adsorption=V i/ c
V-adsorption- Adsorption capacity, unit of measurement
(cm3/g)
-total volume of adsorption gas, unit of measurement
(cm3/g)
-coal sample weight, unit of measurement (g)
Data Calculation and Report
Adsorption Isotherm
According to adsorption capacity of each balance pressure V
and pressure F drew the adsorption isotherm.
Experiment Precision
5.1 Repeatability
VL repeatability of relative error less than *5%
PL repeatability of relative error less than *5%
5.2 Reproducibility
VL reproducibility of relative error less than *0%
PL reproducibility of relative error less than *0%
5.3 Sample experimental weight
Related coefficient R of P/V and P is greater than 0.*8
Sample experimental quality
P/V and its relative coefficient R >0.*8
