多层平板双介质DBD装置放电特性及其降解苯/乙烯混合气体的效果

Discharge Characteristics and Degradation Effect of Benzene/Ethylene Mixture Gases in a Multilayer-plate Double Dielectric DBD Device

为研究介质阻挡放电(DBD)在VOCs的降解处理中的应用,该文提出了一种串联式多层平板双介质阻挡放电装置,用于降解混合VOCs。以苯和乙烯为混合VOCs气体,研究了混合VOCs气氛下,串联式多层平板双介质阻挡放电反应器的放电特性及其降解混合VOCs效果,并对降解产物进行分析。实验结果表明,在固定苯和乙烯体积比的条件下,外加电压为14~18.5 kV时实现稳定放电,提高外加电压,放电电流脉冲强度增加,放电功率和介质电容增大,气隙电容减小;在相同外加电压条件下,提高混合VOCs中乙烯体积分数会抑制放电,随着混合气体中乙烯体积分数的增大,放电电流脉冲的数目和幅值减小,放电强度减弱。外加电压是决定混合VOCs降解的关键参数,提高外加电压,混合VOCs中苯和乙烯的降解率均呈现上升趋势。混合VOCs降解苯与乙烯最佳体积比为1:1,外加电压从14 kV提高至18.5 kV时,苯和乙烯的降解率分别提高了27.3%和33.3%,达到33.2%和71.7%。采用傅里叶红外光谱分析苯和乙烯降解产物发现,苯的中间降解产物为甲酸和CO,最终降解为水和CO2;乙烯的降解产物主要为CO2和CO。

Dielectric barrier discharge(DBD)has been widely used in the degradation of VOCs.In the present study,a series multilayer-plate double dielectric barrier discharge device is proposed and applied for degradation of mixture VOCs.A mixture of benzene and ethylene is taken as VOCs gas,and the discharge characteristics as well as degradation effect of the mixed VOCs in the series multilayer-plate double-dielectric barrier discharge reactor under the mixed VOCs atmosphere are studied.The degradation products are analyzed.The experimental results show that stable discharge can be achieved as the voltage ranging from 14 to 18.5 kV is applied under the condition of a fixed volume ratio of benzene to ethylene.With the increase of the applied voltage,the discharge current pulse intensity,the discharge power and dielectric capacitance will increase while the air gap capacitance will decrease.Under the same applied voltage,increasing ethylene volume fraction in mixed VOCs can inhibit the discharge.With the increase of ethylene volume fraction in mixed gas,the number and amplitude of discharge current pulse and the discharge intensity will decrease.The applied voltage is a key parameter to determine the degradation of mixed VOCs,and the degradation rate of benzene and ethylene in mixed VOCs increases with the increase of applied voltage.The optimum volume ratio of benzene to ethylene is 1:1.When the applied voltage increases from 14 to 18.5 kV,the degradation rates of benzene and ethylene are increased by 27.3%and 33.3%,reaching 33.2%and 71.7%,respectively.Fourier transform infrared spectroscopy(FTIR)is used to analyze the degradation products of benzene and ethylene.It is found that the intermediate degradation products of benzene are formic acid and CO,and the final degradation products are water and CO2.The main degradation products of ethylene are CO2 and CO.