二甲醚掺混低发热量煤层气混合气体的互换性研究

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

国内天然气产量虽然增长迅速,但仍然满足不了急剧增长的消费率,补充非常规天然气,对于缓解国内天然气短缺、优化能源结构尤为重要。中国煤层气资源丰富,但利用率极低,尤其是低发热量煤层气,因其甲烷浓度达不到直接利用的要求,不得不排入大气中,造成巨大的能源浪费。分别通过AGA和Weaver指数法研究了不同二甲醚掺混比例下低发热量煤层气、二甲醚混合气体与天然气及液化石油气的互换性。结果表明:可以考虑在低发热量煤层气中掺混二甲醚以提高其利用效率;与天然气进行互换时,二甲醚掺混比例宜控制在80%,但不建议该掺混气体与液化石油气互换。此外,考虑到低发热量煤层气利用的可能渠道是并入城镇天然气管网,分析了混合气体并入城镇天然气管网或长输管网的互换性及其压缩因子对体积计量的影响。

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.