基于GC-SCD的变压器油中多重硫化物分析及硫醇腐蚀反应实验研究

Analysis of Multiple Sulfides in Transformer Oil and Experimental Study on Mercaptan Corrosion Mechanism Based on Gas Chromatography-Sulfur Chemilecminescence Detection

针对变压器油中腐蚀性硫难以定量分析的问题,建立了以气相色谱仪和硫化学发光检测器联用来检测变压器油中多重硫化合物的方法。该方法依据各硫化物的保留时间来完成多种硫化合物的定性分析,并应用外标法进行定量分析。通过对比实验确定了对变压器油中多重硫化物进行准确定性与定量分析的载气流速、初始炉温及升温程序等检测条件。应用该方法对硫物质的量浓度在1×10^（-6）^5×10^（-3） mol/L之间的变压器油样品进行了检测,并且研究了变压器油中不同类型硫醇与铜反应的相关机理。研究结果表明：硫含量与色谱峰面积呈线性关系,测试的相对标准偏差也满足定性与定量分析的需求;当变压器油中仅含一种硫醇时,老化仅生成相应的二硫醚产物;而当变压器油中含有多种硫醇时,不同硫醇会发生交联反应,除生成各自对应的二硫醚产物之外,还会生成新的硫醚。论文确立了利用气相色谱-硫化学发光检测器测试变压器油多种硫成分的相关方法和检测条件,提出了硫醇与铜反应的新机理,可为多重硫化物的定量分析提供参考。

To quantitatively analyze the corrosive sulfur in transformer oil, we put forward a test methodology by gas chromatograph and sulfur chemiluminescence detection. Sulfur compounds were firstly qualitatively analyzed according to their retention time, based on which the compounds were quantified accordingly with an external calibration scheme. The preferable test conditions, including carrier gas flow rate, initial oven temperature and heating procedure for both qualitative and quantitative analysis of multiple sulfides in the transformer oil, were elucidated and finalized by comparative studies. Moreover, we analzyed the oil samples with sulfides varying from 1×10^（-6） mol/L to 5×10^（-3） mol/L, and studied the reaction mechanism between different mercaptans in the transformer oil and the copper. The measured results indicate that the sulfur contents have a linear relationship with the gas chromatograph peak area, and the relative standard deviation well satisfies the specified requirements of precise quantitative and qualitative analyses. The reaction process with one kind of mercaptan during transformer oil aging may only generate corresponding disulfide, while multiple mercaptans interaction can bring about crosslinking reactions, and cause new thioether apart from corresponding disulfides. The test methodology and conditions by gas chromatograph and sulfur chemiluminescence detection were established to analyze the multiple sulfide in transformer oil, and a new mechanism of mercaptan-copper reaction was put forward. The above method can provide a useful reference for the quantitative analysis of multiple sulfide.