纸浆纯化处理工艺对超高压绝缘纸性能的影响

Effect of Pulp Purification Process on Properties of Extra High Pressure Insulating Paper

关键词:  绝缘纸  碳酸氢镁  冷碱抽提  木质素  介质损耗

Key Words:insulating paper  magnesium bicarbonate  cold caustic extraction  lignin  dielectric loss

摘要:本研究以硫酸盐云杉浆为原料，探讨了碳酸氢镁和醋酸镁对纸浆纯化处理效果的差异。采用冷碱抽提、过氧化氢漂白工艺对纸浆进行纯化，并对纸浆的化学组分和纸张电气性能进行分析。结果表明，相比醋酸镁，碳酸氢镁对Na⁺的置换作用更强，对纸浆化学性能的提升更为显著。碳酸氢镁处理能够使纸浆水抽提液pH值和电导率满足500 kV超高压变压器匝间绝缘纸的指标要求。冷碱抽提和过氧化氢漂白均可有效去除木质素，提高纸浆α-纤维素含量，有效降低纸张的介质损耗。其中，冷碱抽提对纸张电气性能的提升效果更显著，可降低纸张在全频段的相对介电常数，并使浸油后的绝缘纸在工频下的tanδ值降低61.6%。

Abstract:In this study， the differences of the treatment effect of magnesium bicarbonate and magnesium acetate on spruce kraft pulp were discussed. The pulp was treated by cold caustic extraction and hydrogen peroxide bleaching， the pulp components and electrical properties of the paper were analyzed. The results showed that compared with magnesium acetate， magnesium bicarbonate showed a stronger substitution effect on Na⁺ and could significantly improve the chemical properties of pulp. The pH value and conductivity of pulp aqueous extract could meet the requirement of 500 kV transformer coil winding paper by treating with magnesium bicarbonate. Treating the pulp via cold caustic extraction and hydrogen peroxide bleaching could effectively remove the lignin， improve the α-cellulose content of pulp， and reduce the dielectric loss of paper. Compared with hydrogen peroxide bleaching， the electrical characteristics of the paper could be improved more effectively by cold caustic extraction， the relative permittivity of paper could be reduced in the full-band， and the tanδ value of the oil paper at the power frequency could be reduced by 61.6%.