高含硫污水氯化物测定方法的改进和优化

炼油设备腐蚀程度及速度与氯化物含量关系密切,氯化物检测是炼油装置腐蚀监测的重要项目之一。炼油装置的污水中含有大量的硫化物和氨氮等干扰物质,给污水中氯化物的准确测定造成困难。对比了几种常见的前处理方法,发现对样品进行过滤、加热挥发、酸性条件下双氧水消解和碱性条件下煮沸等处理后可消除硫化物和氨氮的干扰。结合实际情况对硝酸银滴定法和硝酸汞滴定法的适用性进行了评选,评选结果表明,硝酸汞滴定法稳定性好,检出限更低,更贴近腐蚀监测的实际需要。采用改进后的新测定方法来测定高含硫污水样品,多次平行测定的相对标准偏差为0%～16.95%,加标回收率为93.85%～104.59%。

Improvement and Optimization of Testing Methods for Chloride in High - sulfur Sour Water

The degree of corrosion and corrosion rate of refinery equipment are closely related to chlorides content.Therefore,the testing of chlorides in one of important testing items in corrosion monitoring of refinery process units.The large amount of sulfides,ammonia and nitrogen etc in the sour water of refinery imposes great difficulties in the accurate testing of chlorides in sour water.Through the testing,several common pre-treatment methods are screened and selected.The interference of chlorides,ammonia and nitrogen can be eliminated by filtration,thermal vaporization,oxydol counteracting at acidic conditions and boiling at alkaline conditions.The applicabilities of silver nitrate titration method and mercury nitrate titration method are evaluated.The results show that the mercury nitrate titration method is good in stability,lower in testing limit,which is more applicable in corrosion monitoring.The multiple tests of high-sulfur sour water samples by the new improved testing method demonstrates that the relative deviation is 0% ～ 16.95,and spiked recovery is 93.85% ～ 104.95%.