| 摘要 |
PURPOSE:To provide insulating oil superior to oxidation stability, retarding capability of tandelta max, and hydrogen gas absorbency, and to provide its manufacture. CONSTITUTION:The first purified mineral oil whose total nitrogen component Nt is 15ppm or less, sulfide type sulfur Sf is 10ppm or less, and titralin and/or indane family aromatic hydrocarbon T&I are 10-35wt.% is manufactured by hydrogenation of the first mineral oil fraction. The second purified mineral oil whose total sulfur component St is 0.5-2.0wt.%, and Sf is 0.2-0.9wt.% is manufactured by solvent extraction in a specified condition of the raffinate yield of the second mineral oil fraction. The first purified mineral oil and the second purified mineral oil are mixed in a ratio of 99.5:0.5-91.0:9.0. The mixture is treated with a solid adsorbent after no long-chain alkylbenzene or after mixing a specified amount of long-chain alkylbenzene to obtain insulating oil whose basic nitrogen Nb is 1ppm or less, non-basic nitrogen Nn is 15ppm or less, Sf is 50-150ppm, and T&I are 10-35wt.%. |
