Measurement method of bubble behavior by optical probe in gas-liquid bubble column reactor
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摘要:
本文分别采用电导探针和光纤探针测量气液鼓泡床反应器中的气含率、气泡速率和气泡弦长等气泡行为，结果表明光纤探针对气泡具有响应迅速、阶跃显著的特点。将光纤探针信号进行方波化处理，探针在气相中的采样点数与总采样点数之比即为局部气含率，再沿径向积分可得平均气含率，以压差法测得的平均气含率为基准，光纤探针比电导探针准确性更高。将改造后的光纤探针应用于高温、高压、液相为有机体系的气液鼓泡床反应器，测得该反应器的气含率呈中心及边壁低、0.4倍半径处最大的抛物形分布。因此，开发的光纤探针可用于高温、高压、液相有机体系中气泡行为的测量。
Abstract:Gas holdup, bubble velocity and bubble chord length in gas-liquid bubble column reactor were measured by using optical probe and conductive probe. It was shown that optical probe has rapid and marked step response to bubbles. When the probe signal data are converted into square wave, the ratio of the sampling points in gas phase to the total sampling points is the local gas holdup. Radial integral of local gas holdup is average gas holdup. Comparison among the gas holdups measured by pressure difference, optical probe and conductive probe shows that optical probe is more accurate than conductive probe. Modified optical probe was applied to gas-liquid bubble column reactor with high temperature, high pressure and organic solvent system. The radial profile of gas holdup was in the shape of parabolic. Gas holdup was lower at center and wall, higher at two-fifth of the radius. These shows that optical probe is suitable for the measurement of bubble behavior in high temperature, high pressure, organic system.
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Key words:
- optical probe /
- signal identification /
- gas holdup /
- bubble velocity /
- bubble chord length
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图 6 不同方法所得平均气含率的比较
Figure 6. Comparsion of average gas holdup measured by different methods
图 8 探针法计算得到的表观气速与实际表观气速对比
Figure 8. Comparison between superficial gas velocity calculated by probe method and practical superficial gas velocity
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