GB/T 35210.2-2020Determination methods of methane isothermal adsorption of shale—Part 2: Gravimetric method (English PDF)

1 Scope

This part of GB/T 35210 specifies the gravimetric method for the determination of shale methane isotherm adsorption:

This section applies to the determination of shale adsorption capacity for methane gas, other rock types can be implemented by reference:

2 Normative references

The following documents are indispensable for the application of this document: For dated reference documents, only the dated version applies to this article

Pieces: For undated references, the latest version (including all amendments) applies to this document:

GB/T 474 Coal sample preparation method

GB/T 29172 Core Analysis Method

3 Terms and definitions

The following terms and definitions apply to this document:

3:1

Excessadsorption

The amount of adsorption obtained directly from the experiment:

3:2

Absoluteadsorption

Consider the amount of adsorption after correction for the density (or volume) of the adsorption phase, that is, the true adsorption amount:

3:3

Langmuir volume

Maximum adsorption capacity

VL Absolute adsorption capacity at infinite pressure:

3:4

Langmuirpressure

PL The absolute adsorption capacity is the pressure corresponding to 1/2 the Ran's volume:

4 Method summary

Place the prepared shale sample in a sealed chamber, perform methane adsorption at a constant temperature and different pressure measurement points, and use a magnetic suspension balance

The recorded mass change is used to obtain the mass of the adsorbed methane gas, and then the shale adsorption characteristic parameters are calculated according to the Langmuir theoretical model 1):

And draw the adsorption isotherm curve:

1) The Langmuir theoretical model equation is one of the commonly used adsorption isotherm equations, which was developed by the physical chemist Langmuir Itying in 1916

Based on the molecular motion theory and some assumptions: Now widely used in adsorption: