车用压缩天然气新标准GB 18047-2017解读

Interpretation of the revised standard GB 18047-2017 for compressed natural gas as vehicle fuel

关键词:  车用压缩天然气  GB 18047-2017  技术要求  试验方法

Key words:  compressed natural gas(CNG)  GB 18047-2017  technical requirement  test method

摘要:

从技术要求和试验方法的变化两个角度对GB 18047-2017《车用压缩天然气》新标准进行了详细解读,并指出新标准中待完善之处。新标准中车用压缩天然气的检验项目没有发生太大的变化,只有部分项目的技术要求发生了变化。其中,总硫(以硫计)的技术要求上限值由200 mg/m³降低到100 mg/m³。在水含量/水露点方面,首次以“水的质量浓度”代替“水露点”衡量环境温度不低于基准分界点时车用压缩天然气中的含水状态。新标准丰富和扩充了各项目的试验方法,方法的选择性增多,但同时也对各项目的仲裁试验方法进行了规定。另外,高位发热量下限值不符合实际情况,建议适当提高高位发热量的标准,并在车用压缩天然气技术指标中新增“液态烃含量/烃露点”检测项目。

Abstract:

The new revised standard of GB 18047-2017 Compressed Natural Gas for Vehicles is explained in detail from the points of view of the technical requirements and the change of test methods, and indicates that the new standard needs to be improved. It has been found that the technical requirements of CNG haven’t changed a lot except for total sulphur (in terms of sulphur) which has decreased from 200 mg/m³ to 100 mg/m³. In the aspect of water content/water dew point, it is the first time to use “water mass concentration” instead of “water dew point” to evaluate the water condition in CNG when the environmental temperature is below the reference dividing point. Moreover, the test methods of each technical requirement have been enriched and expanded overwhelmingly, while the arbitration methods are also specified which are almost the same as the old standard.In addition, the lower limit value of superior calorific value does not accord with the actual situation. It is suggested that the standard of superior calorific value should be raised appropriately, and a new detection item“liquid hydrocarbon content/hydrocarbon dew point” should be added to the technical index of compressed natural gas for vehicle use.