El-Harbawi Mohanad, Al-Mubaddel Fahad
Department of Chemical Engineering, King Saud University, Riyadh, 11421, Saudi Arabia.
Fellow, King Abdullah City for Renewable and Atomic Energy: Energy Research and Innovation Center, (ERIC), Riyadh, 11451, Saudi Arabia.
Sci Rep. 2020 Apr 14;10(1):6295. doi: 10.1038/s41598-020-63354-4.
Transformers reduce the voltage from overhead powerlines to voltages acceptable for city/neighbourhood needs. Overheating of transformer cooling fluids presents a serious hazard. In this work, the risk of fires and explosions due to vaporisation of the hydrocarbon components of mineral oil, which is used as a transformer cooling fluid in electrical substations, was investigated. The compositions of new and used mineral oil from an electrical substation in Riyadh were analysed using gas chromatography-mass spectrometry, and C to C hydrocarbons were detected. The majority of the components were alkanes, alkenes, or alkynes; some ketone, alcohol, aromatic, and anhydride species were also detected. Approximately 25% of the compounds comprising the new oil sample were alkanes, whereas more than 33% of the used oil sample components were alkanes. The lower and upper flammability limits (LFL and UFL) of the mixtures were found to be 0.88 and 5.75 vol.% for the new oil and 0.47 and 3.05 vol.% for the used oil, respectively. These values were used to construct a flammability diagram. The results indicated that the new and used oil vapour mixtures were not flammable at 25 °C and 1 atm, but would become flammable at 77 and 115 °C.
变压器将架空电力线的电压降低到城市/社区需求可接受的电压。变压器冷却液过热会带来严重危险。在这项工作中，研究了由于矿物油的碳氢化合物成分汽化而导致火灾和爆炸的风险，矿物油在变电站中用作变压器冷却液。使用气相色谱 - 质谱法分析了利雅得一个变电站新的和使用过的矿物油的成分，并检测到了C到C的碳氢化合物。大多数成分是烷烃、烯烃或炔烃；还检测到了一些酮、醇、芳烃和酸酐类物质。构成新油样品的化合物中约25%是烷烃，而使用过的油样品成分中超过33%是烷烃。发现新油混合物的下限和上限燃烧极限（LFL和UFL）分别为0.88和5.75体积%，使用过的油分别为0.47和3.05体积%。这些值用于构建燃烧性图。结果表明，新的和使用过的油蒸气混合物在25°C和1个大气压下不可燃，但在77和115°C时会变得可燃。
