焊管2025，Vol.48Issue(9)：55-61,7.DOI:10.19291/j.cnki.1001-3938.2025.09.009
井下大功率电加热器用氧化镁导热和绝缘性能对比
Comparison of Thermal Conductivity and Electrical Insulation in Magnesium Oxide for Downhole High-power Electric Heaters
摘要
Abstract
To optimize the selection of insulating and thermally conductive media for downhole high-power electric heaters,a systematic investigation was conducted on eight different grades of fused MgO.Key properties,including particle size distribution,bulk density,thermal conductivity,breakdown strength,and microstructure,were thoroughly characterized.The dispersion in breakdown strength was further analyzed using the Weibull distribution.The results show that thermal conductivity is governed by two primary factors:the crystalline quality and defect density of the powder,and the bulk density(porosity)and particle size(interface density),which are largely determined by particle morphology and size distribution.At lower temperatures,the insulation performance is significantly affected by factors such as the raw material density,particle size distribution,impurity content,and crystal defects,resulting in significant differences in the breakdown strength of the samples.As temperature increases,the influence of these factors weakens,and the breakdown strength of the samples converges,indicating that the ion conductivity activation mechanism dominates at high temperatures.Furthermore,powders with higher crystalline quality and fewer defects yielded higher thermal conductivity.An optimal particle size distribution resulted in a denser sintered compact with reduced porosity,leading to superior bulk density,thermal conductivity,and insulation properties.Consequently,samples sintered from such optimal powders exhibited the highest consistency in breakdown strength and overall reliability.This study provides a theoretical basis for selecting MgO raw materials for downhole high-power heaters.关键词
井下大功率电加热器/MgO/绝缘性能/热导率/击穿强度Key words
downhole high-power electric heaters/MgO/insulating property/thermal conductivity/breakdown strength分类
矿业与冶金引用本文复制引用
刘璇,汪海涛,肖群星,杨瑶,窦璐,张万鹏,谢航,王曦宁..井下大功率电加热器用氧化镁导热和绝缘性能对比[J].焊管,2025,48(9):55-61,7.基金项目
中国石油集团公司关键核心技术攻关项目"井下大功率电加热器研制"(项目编号2024ZG23) （项目编号2024ZG23）
中国石油天然气集团有限公司青年科技专项"煤炭地下干馏用井下大功率加热器中绝缘氧化镁瓷柱制备关键技术研究"(项目编号2024DQ03222). （项目编号2024DQ03222）
