红外光谱法和库仑滴定法测定全硫的方法比较

Comparison of infrared spectroscopy and Coulometric titration for determination of total sulfur

为了合理地采用红外光谱法或库仑滴定法进行煤中的全硫测定以保证测定结果的准确,分析红外光谱法和库仑滴定法的测定原理,比较仪器设备系统校准方法,探讨测定过程的误差来源,提出除相似因素外,采用红外光谱法测定全硫含量时其抽气流量、比较水平等参数设置影响最大,采用库仑滴定法测定全硫含量时其电解液、搅拌器等硬件设备影响最大。每种方法选定3种煤标准物质进行5次重复试验,通过比较不确定度和相对标准偏差,从而确定库仑滴定法的准确度更优,红外光谱法的精密度更优。当测定低硫煤时,两者可以相互替代;当测定高硫煤时,建议使用库仑滴定法或采用红外光谱法时用高硫标煤重新进行系统校正后再进行测试。

In order to reasonably use infrared spectroscopy or Coulometric titration to determine total sulfur in coal to ensure the accuracy of the determination results,this paper analyzed the principle of infrared spectroscopy and Coulometric titration,compared the calibration methods of instrument and equipment system,and discussed the error sources in the determination process.It is proposed that besides the similar factors,the parameters such as extraction flow rate and comparison level have the greatest influence on the determination of total sulfur content by infrared spectroscopy.The hardware equipment such as electrolyte and stirrer have the greatest influence on the determination of total sulfur content by Coulometric titration.Three kinds of coal reference materials were selected for each method for five repeated tests,by comparing the uncertainty and relative standard deviation,it is determined that the accuracy of Coulometric titration is better and the precision of infrared spectrometry is better.When determining low sulfur coal,the two methods can replace each other;when determining high sulfur coal,it is suggested to use Coulometric titration or infrared spectrometry to conduct system correction with high sulfur standard coal before testing.