Study of furanic compounds sorption behavior in transformers’ insulating materials

IF 5.3 2区化学 Q2 CHEMISTRY, PHYSICAL

Journal of Molecular Liquids Pub Date : 2025-04-08 DOI:10.1016/j.molliq.2025.127564

Miguel A.J. Teixeira , Luanna Maia , Shanika Y. Matharage , Zhongdong Wang , Mário M.Q. Simões , Inês Portugal , Carlos M. Silva

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Abstract

Deterioration of electric transformers’ insulating systems can be monitored using specific markers, such as furanic compounds formed by degradation of cellulosic materials (insulating paper) impregnated with mineral oil. However, the presence of these markers in the insulating oil can be masked by their adsorption on paper, which may occur during aging tests and/or the preparation of aged oil samples for analysis. Hence, it is important to assess the partitioning of aging markers in insulating systems comprising mineral oil and paper. In this work, furfural (FAL) and furfuryl alcohol (FOL) were chosen as degradation markers to study adsorption equilibrium and kinetics of furanic compounds in oil-paper systems, at 30 °C. Two insulating papers were tested, using distinct initial moisture content and FAL/FOL mass ratio. Overall, the results showed that the partition of FAL and FOL in the oil-paper systems is influenced by the solute’s molecular structure, by the morphological surface of the paper, and by its moisture content. In the range 3.2 wt.% to 8.7 wt.% H₂O, when the paper moisture content increases the concentration of furanic compounds in the oil is lower which means the furanic compounds migrate to the paper. Single and multicomponent equilibrium adsorption data were successfully fitted to a linear isotherm equation and kinetic data were fitted to pseudo-first and pseudo-second order models. These models are useful to plan the analysis of degradation markers in oil-paper insulating systems of electric transformers, which should consider their partition in both phases.

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变压器绝缘材料中呋喃化合物吸附行为研究

变压器绝缘系统的劣化可以用特定的标记物来监测，例如由浸渍矿物油的纤维素材料（绝缘纸）降解形成的呋喃化合物。然而，绝缘油中这些标记物的存在可被它们在纸上的吸附所掩盖，这可能发生在老化试验和/或制备用于分析的老化油样过程中。因此，评估由矿物油和纸组成的绝缘系统中老化标记物的分配是很重要的。本研究选择糠醛（FAL）和糠醇（FOL）作为降解标记物，研究了呋喃类化合物在30℃油纸体系中的吸附平衡和动力学。采用不同的初始含水率和FAL/FOL质量比对两种绝缘纸进行了测试。总体而言，研究结果表明，油纸体系中FAL和FOL的分配受溶质分子结构、纸的形态表面和含水量的影响。在3.2 wt.% ~ 8.7 wt.% H2O范围内，随着纸张含水率的增加，油中呋喃化合物的浓度降低，这意味着呋喃化合物向纸张迁移。单组分和多组分平衡吸附数据成功地拟合为线性等温线方程，动力学数据成功地拟合为伪一阶和伪二阶模型。这些模型可用于规划变压器油纸绝缘系统中降解标记物的分析，并应考虑降解标记物在两个阶段的划分。

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来源期刊

Journal of Molecular Liquids 化学-物理：原子、分子和化学物理

CiteScore

10.30

自引率

16.70%

发文量

2597

审稿时长

78 days

期刊介绍： The journal includes papers in the following areas: – Simple organic liquids and mixtures – Ionic liquids – Surfactant solutions (including micelles and vesicles) and liquid interfaces – Colloidal solutions and nanoparticles – Thermotropic and lyotropic liquid crystals – Ferrofluids – Water, aqueous solutions and other hydrogen-bonded liquids – Lubricants, polymer solutions and melts – Molten metals and salts – Phase transitions and critical phenomena in liquids and confined fluids – Self assembly in complex liquids.– Biomolecules in solution The emphasis is on the molecular (or microscopic) understanding of particular liquids or liquid systems, especially concerning structure, dynamics and intermolecular forces. The experimental techniques used may include: – Conventional spectroscopy (mid-IR and far-IR, Raman, NMR, etc.) – Non-linear optics and time resolved spectroscopy (psec, fsec, asec, ISRS, etc.) – Light scattering (Rayleigh, Brillouin, PCS, etc.) – Dielectric relaxation – X-ray and neutron scattering and diffraction. Experimental studies, computer simulations (MD or MC) and analytical theory will be considered for publication; papers just reporting experimental results that do not contribute to the understanding of the fundamentals of molecular and ionic liquids will not be accepted. Only papers of a non-routine nature and advancing the field will be considered for publication.