基于强电场放电协同水力空化的气液传质研究

Research on Gas-liquid Mass Transfer Based on Strong Electric Field Discharge Cooperate with Hydrodynamic Cavitation

为提高氧活性粒子与水的传质速率,利用自行研制的高浓度氧活性粒子溶液产生设备,通过对液相单位体积传质系数(kLa)的计算,研究了水力空化气液混溶过程中,水温、水力空化气液混溶器进、出水端压力差(p_(in-out))和气液体积比(VG/VL)及pH值等关键参量对氧活性粒子与水传质速率的影响。研究结果表明:氧活性粒子经水力空化作用传质进入水中的传质系数远高于后续管路中的传质系数,说明水力空化对氧活性粒子向水中的传质过程起着关键作用。此外,k La随水温(10~30℃)升高,先增大后减小,随p_(in-out)(0.098~0.305 MPa)与VG/VL(0.025~0.125)增加而增加,随p H值(2.54~10.63)增加而减小,当水温为20℃,pH值为2.54,p_(in-out)为0.305 MPa,VG/VL为0.125时,kLa最大,为10.62 s^(–1)。通过对以上关键参量的研究,可进一步优化大气压强电场放电协同水力空化气液混溶高级氧化技术的应用参数与途径。

We developed the equipment of oxygen active species generation based on the technology to study the effects of key parameters on mass transfer rate, such as water temperature, the pressure difference of water inlet and outlet （pin-out）, gas-liquid injection volume ratio （VG/VL）, and pH value, through the calculation of mass transfer coefficients kLa. The results indicate that the mass transfer coefficient kLa of the oxygen active species mass transfer to water by hydrodynamic cavitation （t0-t1） is much higher than that in the subsequent water pipe （t1-t6）. Thus the hydrodynamic cavitation plays a key role in the mass transfer process of oxygen active species to water. In addition, kta first increases then decreases with the increase of water temperature （10-30 ℃）, and increases with the increase of pressure difference （0.098-0.305 MPa） and gas-liquid injection volume ratio （0.025-0.125）, but reduces with the increase of pH value （2.54-10.63）. The maxi- mum value ofkLa is 10.62 s^-1, when the water temperature is 20℃, pH is 2.52, pin-out is 0.305 MPa, VG/VL is 0.125. This research can optimize the design and application parameters of hydrodynamic cavitation gas-liquid mixed solvent technology.