title: Combined effect of constant high voltage electrostatic field and variable frequency pulsed electromagnetic field on the morphology of calcium carbonate scale in circulating cooling water systems.
abstract: Research on scale inhibition is of importance to improve the heat transfer efficiency of heat exchangers. The combined effect of high voltage electrostatic and variable frequency pulsed electromagnetic fields on calcium carbonate precipitation was investigated, both theoretically and experimentally. Using energy dispersive spectrum analysis, the predominant phase was found to be CaCO(3). The formed crystal phases mainly consist of calcite and aragonite, which is, in part, verified by theory. The results indicate that the setting of water flow velocity, and high voltage electrostatic and variable frequency pulsed electromagnetic fields is very important. Favorable values of these parameters can have a significant anti-scaling effect, with 68.95% of anti-scaling ratio for scale sample 13, while unfavorable values do not affect scale inhibition, but rather promoted fouling, such as scale sample 6. By using scanning electron microscopy analysis, when the anti-scaling ratio is positive, the particle size of scale was found to become smaller than that of untreated sample and the morphology became loose. The X-ray diffraction results verify that the good combined effect favors the appearance and growth of aragonite and restrains its transition to calcite. The mechanism for scale reduction is discussed.
authors.affiliation: College of Science, Inner Mongolia University of Technology, Hohhot 010051, China E-mail: ejzhao@yahoo.com.
authors.forename: Ju-Dong
authors.initials: JD
authors.lastname: Zhao
authors.affiliation: College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot 010051, China.
authors.forename: Zhi-An
authors.initials: ZA
authors.lastname: Liu
authors.affiliation: College of Science, Inner Mongolia University of Technology, Hohhot 010051, China E-mail: ejzhao@yahoo.com.
authors.forename: Er-Jun
authors.initials: EJ
authors.lastname: Zhao
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D003460:Crystallization; D004560:Electricity; D004574:Electromagnetic Fields; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D013052:Spectrometry, X-Ray Emission; D055672:Static Electricity; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D014867:Water; D002119:Calcium Carbonate