Study On The Crystallization Process Of Sodium Chloride Solution By Alternating Electromagnetic Field

Sodium chloride is the major component of salt scale in some domestic oil and gas field,such as Zhongyuan Oilfield,Jianghan Oilfield and Changqing Oilfield.It is difficult to remove by chemical methods for the sake of its stable chemical properites.However,it can be inferred that the crystallizaion of sodium chloride can be effectively reduced by using the alternating electromagnetic field,according to some theories and the properties of sodium chloride solution.In this paper,we study the law in which way alternating electromagnetic field affect the crystallization process of sodium chloride solution when we change the frequency,current or wave of the field.After the treatment of the alternating electromagnetic field,we analyze the change rate of the precipitates quality when the solution stands for a while,the change rate of the residual quality of the salt placed into the solution,the change rate of the surface tension coefficient,the change rate of conductivity,the change of the sodium chloride droplet's crystallization of and the change of Raman Spectra.On the basis of the above,we study the law in which way alternating electromagnetic field affect the crystallization process of sodium chloride solution when we change the frequency,the current or the wave.It can be summarized as follow:1.As to frequency: To have the most influence on the crystallization process of sodium chloride solution,the frequency of the alternating electromagnetic field should be chosen as 25 kHz to sinusoidal wave and 20-25 kHz to square-wave.After the treatment of the field above,the precipitates quality when the solution stands for a while decreases the most,by-28.57% to sinusoidal wave and-20.00% to square-wave.The residual quality of the salt placed into the solution increases the most,by 17.08% to sinusoidal wave and 6.67% to square-wave.The surface tension coefficient increases the most,by 7.35% to sinusoidal wave and 3.89% to square-wave.The sodium chloride droplet's crystallization tend to aggregation distribution.The raman intensity increases the most for square-wave,by 1.09% to the 1st raman band,1.04% to the 2nd raman band,1.03% to the 3rd raman band,1.13% to the 4th raman band,1.06% to the 5th raman band,1.53% to the 6th raman band.It can be conjectured that 25 kHz is very special which may produce resonance of sodium chloride solution.The impact is amplified that the alternating electromagnetic field makes on,to this frequency.2.As to current: To have the most influence on the crystallization process of sodium chloride solution,the current value of the alternating electromagnetic field should be increased the most within the allowable range.When the current value is increased to 1.4A which is the maximum current value that the instrument supported,the precipitates quality decreases by-18.18% to sinusoidal wave,the residual quality increases by 13.23% to sinusoidal wave and 4.60% to square-wave,the surface tension coefficient increases by 1.66% to sinusoidal wave,and the raman intensity increases by 1.17% to the 1st raman band,1.18% to the 2nd raman band,1.20% to the 3rd raman band to sinusoidal wave.The higher current value is,the more impact the alternating electromagnetic field makes.3.As to waveform: To have the most influence on the crystallization process of sodium chloride solution,the waveform of the alternating electromagnetic field should be sinusoidal wave or square-wave,rather than triangular wave.