南京市某CNG加气站大气甲烷体积分数的研究及气象要素对其影响

Study on Atmospheric Methane Concentration of a CNG Filling Station in Nanjing and Influence of Meteorological Elements on it

CNG即压缩天然气是重要的一类人为CH_4排放源,为探明CNG加气站CH_4扩散体积分数及其与气象要素之间的相关性,针对南京浦口区某加气站采用LGR (便携式温室气体分析仪)与气相色谱仪在加气的不同环节对CH_4体积分数进行观测。本文通过南京市某CNG加气站附近CH_4泄露时CH_4体积分数的测量数据,分析加气站加气过程中的不同环节CH_4的体积分数变化及其与气象要素(温度、风速、湿度)的关系。进行观测,并测量了同期不同的气象要素(温度、湿度、风速)。结果表明:加气站确实存在大量CH_4泄露,此CNG加气站CH_4平均体积分数与背景值的差值维持在0.7×10^(-6),尤其在在加气枪拔出瞬间,卸载气体体积分数会达到422.59×10^(-6);CH_4泄露受到气象要素的影响,泄露体积分数与温度、风速存在明显的负相关,且达到极显著水平(|R|=0.866>|R_(0.01)|),与湿度不存在相关性。

CNG, compressed natural gas, is an important source of anthropogenic CH4 emissions. In order to find out the correlation between CH4 concentration of CNG filling station and meteorological elements, a LGR (portable greenhouse gas analyzer) and gas chromatograph were used to observe the CH4 concentration at different refueling links of a gas filling station in Pukou District, Nanjing, and different meteorological elements (temperature, humidity, wind speed) during the same period were measured. The results show that there is a large amount of CH4 leakage in the gas station. The difference between the average concentration of CH4 in the CNG filling station and the background concentration was maintained at 0.7×10^-6, especially at the moment when the gas gun is pulled out, the unloading gas concentration reached 422.59×10^-6. Also, the CH4 leakage is affected by different meteorological factors, the leakage concentration has a significant negative correlation with temperature and wind speed, and reaches a extremely significant level (|R|=0.866>|R0.01|), and there is no correlation with humidity.