与传统在线测量原油含水率的方法相比,高频微波谐振腔微扰法具有受外界环境影响小,不受矿化度影响,测量精度高的特点。由于原油和水的介电常数相差较大,微小的含水率变化会引起介电常数较大变化,使得不同含水率原油对微波场的损耗不同。通过软件仿真的方法可以测量出含微扰源(样品原油)的微波谐振腔的谐振频率和品质因数变化情况,根据矩形谐振腔微扰公式可得出样品原油的介电常数,然后将所得结果代入原油含水率和介电常数关系公式求得原油含水率。并且将铝制边界条件和铜制边界条件下所测得的原油介电常数数据与理论值进行分析,求出其相对百分比误差,得出一种较为简单、实用、快速准确的测量中低含水率原油的方法。
In comparison with the traditional on-line detecting method of moisture content of crude oil, the high-frequency microwave resonant cavity perturbation method is seldom influenced by the external environment and never influenced by the mineralization, and has high detecting accuracy. Since the permittivity of water and crude oil is significantly different, and the small change of water content can change the permittivity greatly, the crude oil with different moisture contents may result in the different losses of microwave field. The change of resonant frequency and quality factor of the microwave resonant cavity contain- ing perturbation source (sample crude oil) are detected by means of software simulation. The permittivity of sample crude oil can be obtained according the perturbation formula of rectangle resonant cavity. And then the obtained result is substituted into the relation formula reflecting crude oil moisture content and permittivity to get the permittivity of the sample moisture content of crude oil. The crude oil permittivity data detected in aluminum and copper boundary conditions is analyzed with the theoretical value, and the relative percentage error is found out. A simple, practical, fast and accurate method to detect the crude oil with medium and low moisture content is obtained.