Low-pressure sorption tests were carried out on samples of selected Polish bituminous coal in coal–methane and coal–carbon dioxide systems. The purpose was to determine the relationship between the petrographic composition of low-rank coal and the amount of gas stored in its porous structure and desorbed from it. The influence of the degree of coalification on the amount of sorbed gas was reduced to minimum, because isotherms of deposition and evacuation of gases were determined on the base coal samples and two concentrates of lithotypes, vitrain and durain, isolated from the original coal. It was found that the sorption capacity of carbon dioxide was related to the pertographic composition, but no such correlation was observed in regard to methane. Langmuir and Dubinin–Radushkevich sorption isotherms and the modified desorption model based on Langmuir equation were chosen. The applied equations gave a very good fit to the experimental data. Calculated parameters corresponding to free adsorption energy in the Dubinin–Radushkevich equation allow concluding on the independence of its mechanism from coal petrography and on the preference of carbon dioxide sorption. Calculated adsorption equilibrium constants in Langmuir’s equation show variability with petrographic composition of coal and have lower values for methane than for carbon dioxide. It was shown that the size of the hysteresis loop depends on the petrographic composition of coal and increases with increase in vitrinite content for both sorbates, which was confirmed by values of areal hysteresis index and hysteresis parameter.

在煤-甲烷和煤-二氧化碳系统中，对选定的波兰烟煤样品进行了低压吸附测试。目的是确定低阶煤的岩石学组成与其在多孔结构中储存并从中解吸的气体量之间的关系。煤化程度对吸附气体量的影响已减至最小，这是因为确定了基煤样品和从原始煤中分离出的两种岩石类型的浓集煤（Vitrain和Durain）的气体的沉积和排空等温线。已经发现二氧化碳的吸附能力与渗透组成有关，但是对于甲烷没有观察到这种相关性。选择了Langmuir和Dubinin–Radushkevich吸附等温线，并选择了基于Langmuir方程的改进解吸模型。应用的方程式非常适合实验数据。在Dubinin-Radushkevich方程中，与自由吸附能相对应的计算参数可以得出其机理与煤岩学的独立性以及对二氧化碳吸附的偏好的结论。Langmuir方程中计算得出的吸附平衡常数显示出随煤的岩石学组成的变化，并且甲烷的值低于二氧化碳的值。结果表明，磁滞回线的大小取决于煤的岩石学组成，并且随着两种吸附剂的镜质体含量的增加而增加，这由面积磁滞指数和磁滞参数的值所证实。