Study on the interchangeability for mixtures of dimethyl ether and low calorific value coalbed methane

China's natural gas production is growing rapidly, but it still can't meet the rapidly increasing consumption rate. It is particularly important to supplement unconventional natural gas to alleviate the situation of natural gas shortage and optimize the energy structure. China is rich in coalbed methane(CBM) resources, but its utilization rate is very low, especially the low calorific value CBM, because its methane concentration cannot meet the requirements of direct utilization and has to be discharged into the atmosphere, resulting in huge energy waste. In this paper, the AGA index method and the Weaver index method are respectively used to analyze the interchangeability for mixtures of dimethyl ether and low calorific value coalbed methane with natural gas or liquefied petroleum gas under different blending rate of dimethyl ether. The resuls show that low calorific value CBM can be considered to blend with dimethyl ether to improve its utilization efficiency. When interchanged with natural gas, the blending proportion of dimethyl ether should be controlled at 80%, but it is not recommended to interchange with LPG. In addition, considering that the utilization channel of low calorific value CBM may be incorporated into urban natural gas pipeline network, the interchangeability of mixed gas incorporated into urban natural gas pipeline network or long-distance pipeline network, as well as the influence of compression factor on volume measurement are also analyzed.