格子Boltzmann方法模拟咸水吸收CO2的Rayleigh对流过程  

Rayleigh convection of carbon dioxide absorption in saline water by lattice Boltzmann simulation

作　　者：付博[1] 田建昌 刘菊 张润叶 陈慕华[1] 朱新宝[1] FU Bo;TIAN Jianchang;LIU Ju;ZHANG Runye;CHEN Muhua;ZHU Xinbao(College of Chemical Engineering,Nanjing Forestry University,Nanjing 210037,Jiangsu,China)

机构地区：[1]南京林业大学化学工程学院,江苏南京210037

出　　处：《化工进展》2021年第2期642-651,共10页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(21606133);江苏省自然科学基金(BK20160922)。

摘　　要：由溶解的CO2引发的Rayleigh对流,对咸水层中CO2的捕获与封存至关重要。为了更加直观地了解该过程的混合规律和盐浓度变化带来的影响,本文采用格子Boltzmann方法 (LBM)对该过程进行了模拟。通过建立包含密度和浓度分布函数的双分布模型,同时引入静电力和体积力等外力项,对293.15K、101kPa下有多个离散的CO2扩散源时的浓度分布进行了模拟。结果表明,模拟得到的Rayleigh对流结构、对流发生时间、流场速度和瞬时传质通量的数量级与前人研究结果一致;在咸水吸收CO2过程中,Rayleigh对流结构可有效强化传质;瞬时传质通量随着时间增长先减小后增大再减小,对应了Rayleigh对流结构产生、发展、稳定的变化过程。同时模拟CO2在纯水和不同盐浓度咸水中的溶解过程结果表明,盐浓度的增加会延迟Rayleigh对流的开始时间、降低传质效率,这与前人的实验结果一致,模拟结果可为不同盐浓度咸水层中CO2的封存提供指导。The Rayleigh convection and mass transfer process caused by the dissolved CO2 is critical for the CO2 capture and storage in the saline aquifers.In order to understand the mixing law and the effect of salt concentration on the process more intuitively,lattice Boltzmann method(LBM)was used to simulate the process.By establishing a double distribution model including density distribution function and concentration distribution function,and the external force terms such as electrostatic force and volume force were introduced into the collision equation and balance distribution function.The change of concentration field in the process of saline water absorbing CO2 with multiple CO2 diffusion sources at 293.15K and 101kPa was successfully simulated.The results showed that the structure of Rayleigh convection,the start time of convection,the velocity of flow field and the order of magnitude of instantaneous mass transfer flux were consistent with the previous research results.The Rayleigh convection structure can greatly promote the mass transfer rate of CO2 absorption in saline water and the instantaneous mass transfer flux increases in the beginning and then decreases with time,which corresponds to the generation,development and stability of Rayleigh convection structure.Simulated dissolution process of CO2 in different salt concentration solutions also showed that the increase of salt concentration will delay the start time of Rayleigh convection and reduce mass transfer rate,which is consistent with experimental results.The simulation results can also provide guidance for the storage process of CO2 in different saline aquifers.

关 键 词：二氧化碳捕集与封存 格子BOLTZMANN方法 模拟 吸收 Rayleigh对流 传质 

分 类 号：TQ021.4[化学工程]