提高碘量法测定天然气中硫化氢效率的方法

碘量法是测定管道输送天然气中硫化氢的一种经典方法,而管道输送天然气中硫化氢含量较低,按照GB/T11060.1–2010方法测定,取样量较大,取样时间长,影响工作效率。针对此问题,从两方面对碘量法进行改进:减小天然气取样量进行试验,并与国标规定取样量时的实验结果进行比对,确定最佳取样量;增大取样流量进行试验,并与国标规定取样流量时的实验结果进行比对,确定最佳取样流量。对硫化氢质量浓度为7.2~14.3,14.3~28.7 mg/m~3的天然气样品进行试验测定,结果表明,将天然气取样量减少为20 L,取样时间分别由200,100 min缩短为40 min;将天然气取样流量设定为750 m L/min,取样时间分别由200,100 min缩短为133,67 min。减少取样量或者提高取样流量,均能缩短管输天然气的取样时间,提高检测效率。

Method of Improving the Efficiency of Determination of Hydrogen Sulfide in Natural Gas by Iodometry

Iodometry is classic method for determining hydrogen sulfide in natural gas. The content of hydrogen sulfide in pipeline natural gas is low, according to the national standard GB/T 11060.1-2010,the sampling volume is large and the sampling time is long, so the working efficiency is affected. In view of this problem,the iodometric method was improved from the following two aspects: the sampling volume of natural gas was reduced and experimental results were compared with those of the national standard sampling,then the best sampling volume was obtained. The sampling flow rate of natural gas was increased and experimental results were compared with those of the national standard sampling flow rate,then the best sampling flow rate was obtained. Hydrogen sulfide samples were detected by the improved method which concentration were 7.2-14.3, 14.3-28.7 mg/m3, respectively. If sampling volume was reduced to 20 L, the sampling time could be reduced to 40 min from 200, 100 min, respectively. If sampling flow rate of natural gas was set at 750 mL/min, the sampling time could be reduced to 133,67 min from 200,100 min, respectively. Reducing the amount of sampling or increasing sampling flow rate can reduce the sampling time of pipeline natural gas, and improve the detection efficiency.