摘要
针对选择性催化还原技术(SCR)存在装置大、运行费用高、催化剂中毒失活等问题,将平均孔径为100 nm的Al2O3陶瓷膜进行疏水改性并组装成膜接触器,以NaClO2水溶液为吸收液,开展陶瓷膜接触器在烟气脱硝领域的应用研究。考察了陶瓷膜接触器在化学吸收脱硝中的稳定性,以及气体流量、吸收液浓度、吸收液流量、吸收液pH等因素对NO脱除率和传质通量的影响,基于阻力串联模型,建立总传质系数方程。研究表明,陶瓷膜接触器在连续600 min运行过程中,NO的脱除效率及传质通量分别稳定在99%和0.038 mol·m^-2·h^-1左右。进气流量的增加会促进NO的吸收,吸收液pH=3时具有最高的氧化吸收性能,同时提高吸收液的浓度会增强NO的脱除效果。NO的传质过程同时受气、液、膜三相阻力控制,传质阻力分析结果表明,可以通过增加气体流速减小气相阻力,增加吸收液浓度同时降低pH减小液相阻力。本研究在烟气脱硝领域具有良好的应用前景。
To overcome the problems of large device,high operating cost and catalyst poisoning and deactivation in the selective catalytic reduction technology(SCR),Al2O3 ceramic membrane with an average pore diameter of 100 nm was hydrophobic modified and assembled into a membrane contactor,NaClO2 was used as absorbent to carry out the application research of ceramic membrane contactor in the field of denitration of flue gas.The stability of ceramic membrane contactor in chemical absorption denitrification and the effect of the process parameters(i.e.gas flow rate,concentration of absorbent,liquid of absorbent,pH of absorbent)on NO removal efficiency and mass transfer flux were investigated in detail.Based on the resistance series model,the total mass transfer coefficient equation was established.The experiments showed that the NO removal efficiency and mass transfer flux of NO were stable at about 99%and 0.038 mol·m^-2·h^-1 during 600 min operation of the ceramic membrane contactor.The increase of the intake air flow will promote the absorption of NO,and the absorption liquid has the highest oxidation absorption performance at pH=3,while increasing the concentration of the absorption liquid will enhance the removal effect of NO.The mass transfer performance of NO is controlled by the resistance of the gas phase,liquid phase and the membrane phase at the same time.The mass transfer resistance analysis results show that the increase of gas flow rate can decrease the gas phase resistance,increasing the concentration of the absorbent and the lower pH can reduce liquid phase resistance.The study has a good application prospect in denitration of flue gas.
作者
周鑫
邱鸣慧
罗平
ZHUO Xin;QIU Minghui;LUO Ping(College of Environmental Science and Engineering,Nanjing Tech University,Nanjing 211816,Jiangsu,China;State Key Laboratory of Materials-Oriented Chemical Engineering,College of Chemical Engineering,Nanjing Tech University,Nanjing 211816,Jiangsu,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2020年第8期3652-3660,共9页
CIESC Journal
基金
国家重点研发计划项目(2016YFC0205700)
国家自然科学基金项目(91534108,21838005)
国家高技术研究发展计划项目(2012AA03A606)。
关键词
陶瓷膜
膜接触器
脱硝
膜吸收
传质过程
ceramic membrane
membrane contactor
denitration
membrane absorption
mass transfer performance
