Table 2: Parameters for modeling results and discussion.

ParameterSymbolUnitValue

Formation temperatureK368
PorosityDimensionless0.05
TortuosityDimensionless3.5
Gas typeCH4
Gas molecule diameterm3.8 × 10−10
Gas molar masskg/mol1.6 × 10−2
Universal gas constantJ/(mol·K)8.3145
Boltzmann constantKBJ/K1.3805 × 10−23
Molar volume of gas under standard conditionm3/mol0.0224
Avogadro’s constant1/mol6.02 × 1023
Langmuir pressureMPa5.82
Isosteric adsorption heat at the gas coverage of zeroJ/mol16,000
The ratio of the rate constant for blockage to the rate constant for forward migrationDimensionless0.5
Pore diameternm2/4/10/20/50/100/200