煤层气资源可采性的综合评价

煤层气资源储量是煤层气开发最基本的物质基础和最关键的地质控制因素,而煤层气的可采性是实践煤层气开发的根本前提。文章首先对影响煤层气资源开采的地质因素进行了归类提纯,在此基础上根据不同矿区工作面煤层的实际测量参数建立了煤层气资源可采性的评判模型,为不同矿区煤层气资源开发实践提供了参考依据。     

An unexpected large continental source of reactive bromine and chlorine with significant impact on wintertime air quality

Halogen atoms affect the budget of ozone and the fate of pollutants such as hydrocarbons and mercury. Yet their sources and significances in polluted continental regions are poorly understood. Here we report the observation of unprecedented levels (averaging at 60 parts per trillion) of bromine chloride (BrCl) at a mid-latitude site in North China during winter. Widespread coal burning in rural households and a photo-assisted process were the primary source of BrCl and other bromine gases. BrCl contributed about 55% of both bromine and chlorine atoms. The halogen atoms increased the abundance of ‘conventional’ tropospheric oxidants (OH, HO₂ and RO₂) by 26%–73%, and enhanced oxidation of hydrocarbon by nearly a factor of two and the net ozone production by 55%. Our study reveals the significant role of reactive halogen in winter atmospheric chemistry and the deterioration of air quality in continental regions where uncontrolled coal combustion is prevalent.