The behavior and model of methane adsorption on coal by ultrasonic enhancement

Abstract

Ultrasonic technology can effectively improve the efficiency of coalbed methane (CBM) extraction and holds a broad application prospect. While the influence of the ultrasonic comprehensive effect on CBM output has been extensively studied, there is still a lack of in-depth discussion and detailed analysis of the specific influence of the single effect on methane adsorption. This article conducted an in-depth study of methane adsorption behavior in three different ways: ultrasonic comprehensive effect (UCE), thermal effect (UTE), and mechanical vibration effect (UMVE) by controlling the experimental conditions. The results indicated that CH4 adsorption was significantly inhibited by the UCE, and this inhibition was mainly influenced by the UTE. In contrast, the UMVE somewhat enhanced the adsorption of CH4. The moisture in the coal did not change the above trend. Furthermore, the promotion of CH4 adsorption by UMVE had an immediate effect, occurring only when UMVE was applied. The essence of promoting adsorption is that UMVE acts on the coal matrix and CH4 adsorption phase as an additional load, subsequently resulting in an increase in adsorption equivalent pressure. Based on the above understanding, the equivalent pressure parameter of CH4 adsorption under UMVE was proposed, and a mathematical model for CH4 adsorption under UMVE was constructed. In addition, a CH4 adsorption model under the UCE was established. The research results have certain reference significance for the application of ultrasonic in coalbed methane mining.