Super critical CH4 adsorption characteristics and applicability of adsorption models for low, middle-rank tectonically deformed coals

SONG Yu; JIANG Bo; LI Ming; LIU Jiegang; LIU Hewu

doi:10.13225/j.cnki.jccs.2016.1852

Abstract：The super critical CH4 adsorption characteristics and applicability for commonly used adsorption theories and the extended models Ⅰ-Ⅲ were comprehensively analysed for low-middle rank tectonically deformed coals (TDCs).The mean fitted variances of type Ⅰ models for different TDCs manifest as primary-＜cataclastic-＜mortar coals ＜schistose-＜wrinkle-＜granulitic-＜scaly-＜mylonitic coal,where the model T and L-F have the best Vm-fitted effects for primary-and brittle sequence TDCs.The fitted variances of type Ⅱ models are significantly higher than those of type Ⅰ models and the model T-BET-1 and T-BET-2 are not suitable for scaly coals.The mean fitted variances of type Ⅲ models manifest as mortar-＜cataclastic-＜primary-＜granulitic-＜wrinkle-＜scaly-＜mylonitic coals and are significantly lower than those of type Ⅰ and Ⅱ models,indicating the better applicability than the former two especially the model DR1-DR3 and DA-3 for the Vm of scaly coals and wrinkle coals.The model DR1-DR3 can better reflect the Vm of mylonitic coals.With the enhancements of tectonic deformation,the adsorption saturations of type Ⅲ models transit from monolayer unsaturated adsorption (primary-,cataclastic-,mortar coals),monolayer saturated adsorption (granulitic-,schistose coals) to multilayer adsorption (scaly-,wrinkle-and mylonitic coals).The adsorption potential (0-13 k J/mol) distributions of primary coals and TDCs decrease with the increase of adsorption spaces based on the adsorption potential theory.The adsorption spaces at the maximum adsorption capacity manifest as primary-≈ cataclastic-＜mortar-＜granulitic-≈ schistose-＜wrinkle-＜mylonitic-≈ scaly coals.The fitness biases shows that the models E-L,L-F,L and T are the most applicable for granulitic coals.The models L,F,T and E-L are suitable for scaly coals,models L,F,E-L,T-BET-3,DR-1,DR-2 are suitable for wrinkle coals and model F and T are also the most suitable.