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从各种不同煤化阶段煤的平均元素组成或煤的高温裂解实验结果可以间接地求得热成因甲烷的产量。为了更好地确定低级煤中甲烷生成的经济潜力,对北达科塔州古新世褐煤进行了无水、密封管高温热裂解实验。应用一系列平行的、活化能介于41～54kcal/mol的一级反应和9.88×10~(-11)S~(-1)的单一频率因子,通过热裂解甲烷产量的方法模拟早期甲烷的生成。将镜质体反射率模型外推到地质升温速率条件下,可看出,要超过300cf/t的甲烷经济门限值需要温度T>120℃且镜质体反射率R_o≥0.9％的条件。在高挥发份B烟煤级或更低级的煤中发现甲烷的富集度超过300cf/t时,大多数情况下可能是由于气体的迁移或近地表(≤3000ft)的微生物作用的结果。
The yield of pyrogenic methane can be obtained indirectly from the average elemental composition of coal or coal pyrolysis experiments at various coalification stages. In order to better determine the economic potential of methane generation in low-grade coal, an experiment was conducted on the pyrolysis of the Paleocene lignite in North Dakota at high temperature. Using a series of parallel first-order activation energies ranging from 41 to 54 kcal / mol and a single frequency factor of 9.88 × 10 ~ (-11) s -1, the methane yield from early methane was simulated by thermal cracking of methane generate. Extrapolation of the vitrinite reflectance model to the rate of geothermal heating shows that methane economic thresholds over 300 cf / t require conditions of temperature T> 120 ° C. and vitrinite reflectance R_o ≥ 0.9%. Concentrations of methane above 300 cf / t are found in high-volatile B bituminous or lower grade coals, most likely as a result of gas migration or near-surface (≤3,000 ft) microbial action.