Abstract:

A cylindrical electrode is arranged at the inlet pipe of the heat exchanger and connected to the positive electrode of the high-voltage power supply to study the influence of the non-uniform electric field formed by the cylindrical electrode on the deposition of CaCO₃ fouling on the heat exchange surface of the experimental section. In comparison, the CaCO₃ scale deposition under the action of the parallel plate electrode (uniform electric field) was discussed. The results showed that applying parallel electrode and the cylinder electrode can inhibit CaCO₃ scale on heat transfer surface deposition, scale inhibition rate increased with increase of voltage (0—5000 V) firstly and then decreased. When applying parallel electrodes, the best scale inhibition voltage value is 1000 V and the best scale inhibition rate is 73.27%. When the cylinder electrode is applied, the best scale inhibition voltage is 500 V and the best scale inhibition rate is 83%. Therefore, the cylinder electrode has better scale inhibition rate, and the best scale inhibition voltage is lower which can reduce the electricity consumption. In addition, SEM analysis shows that CaCO₃ crystal is mainly dendritic aragonite structure at no electric field, while CaCO₃ crystal is mainly calcite structure under the action of the electric field.

Key words: cylinder electrode, CaCO₃ scale, best scale inhibition voltage, CaCO₃ crystal, heat and mass transfer

摘要：

将一圆筒柱面电极布置在换热器入口管道处，并与高压电源正极连接，研究圆筒电极形成的非匀强电场对实验段换热表面CaCO₃污垢沉积的影响。作为对比，同时分析了平行板电极（匀强电场）作用下CaCO₃污垢沉积行为。结果表明，施加平行电极与圆筒电极均可抑制换热表面CaCO₃污垢的沉积，抑垢率随施加电压（0~5000 V）的增加呈现先升高后降低的变化趋势。当施加平行电极时，最佳抑垢电压值为1000 V，最佳抑垢率为 73.27%。当施加圆筒电极时，最佳抑垢电压为500 V，最佳抑垢率为83%。因此，施加圆筒电极具有更好的抑垢效果，同时最佳抑垢电压更低，可降低电的消耗。此外，在无电场作用时，换热表面CaCO₃晶体主要为树枝状文石结构，当施加圆筒或平行电极时，CaCO₃晶体主要为块状方解石结构。

关键词: 圆筒电极, CaCO₃污垢, 最佳抑垢电压, CaCO₃晶体, 传热传质