脱除尾气化学尘雾PM2.5的气液交叉流阵列及内源性机制

Technology and theory for high efficient collection of chemical dust/mist PM2.5 from industrial emissions have become imperatives for the development of process industries in China. A novel gas-liquid cross-flow array (GLCA) with densely anastomosed regular interfaces, dynamically formed by waste water and contaminated emissions themselves, is proposed for dust/mist PM2.5 collection operations driven by the endogenous mechanisms originated from gas-liquid transport dynamic factors instead of external potential driving forces. The scientific key problems are:1) multi-phase fluid dynamics for adjustandcontrol of the characteristic interfacial structure of GLCA; 2) multi-phase transport performances to convert interphase thermodynamic potential differences into velocity field of fine particles moving toward interfaces; 3) prediction of collection efficiency based on microscopic particle trajectory analysis. The main scientific innovative points are: 1)the characteristic separation strcture of GLCA formed synchronously by the emissions thenselves during the separation process, which may cause a bearkthrough in solving the surface renewing problems inherently existing in the solidified separation materials and structures; 2) the endogenous mechanisms, through heat and mass trnsfer, converting the weak residual energy of gas-liquid into driving forces distributed all over around the interfaces for particle separation, which may overcome the drawback in energy effectiveness of external electrostatic field; 3) modelling of particle trajectory and superimposing of "three element velocity" (normal shipping velocity, mass diffusion velocity and thermophoresis velocity), which may constitute a new academic trend valuable in microscopic understandings on the complex boumdary structures of multiphase flow. The research results are expected to promote academic study and benefit technology innovation in this field.

高效脱除尾气化学尘/雾PM2.5新技术及理论是我国过程工业发展之急需。本项目提出废水与含尘雾废气自身构成具有密集交织规整的动态界面结构的气液交叉流阵列，及其将气液两相传递推动力转化为分离PM2.5的内源性机制，实现无外加场源的PM2.5分离新方法。关键科学问题：1）调控动态界面结构的流体动力学规律；2）微小热力学势差推动PM2.5分离的边界层结构；3）基于微粒运动轨迹预测分离效率。主要创新点是1）分离对象自身与分离过程同步产生动态分离界面，突破固体材料与结构的困难；2）通过传热传质途径将气液介质微弱的余能转化为吸引微粒分离的界面功能，克服传统外加场源能效之不足；3）依托界面气液传递产生的微粒"三元"速度（法向跟随速度、浓差扩散速度、颗粒热泳速度）叠加效应及其运动轨迹模型，是多相流边界层复杂结构微观尺度上具有重要科学研究价值的新内容。将对PM2.5减排和多相流界面现象研究产生积极影响。

本项目针对我国过程工业控制尾气排放技术发展所需，开展气液交叉流阵列（GLCA）脱除PM2.5（化学尘/雾）的以废治废创新方法及内源性机制研究，并建立了利用低位余能净化工业废气的循环工艺及设计方法，研究结果为进一步开展工业废气零排放技术创新提供了理论基础和实验依据。.围绕GLCA脱除PM2.5 “流体动力学与传热传质边界层内颗粒‘三元’速度叠加内源性机制”和“基于颗粒运动轨迹的PM2.5分离效率数学模型”两个关键科学问题进行了深入研究，系统地获得了GLCA脱除PM2.5原理认知和过程调控方法。探明GLCA高效脱除PM2.5的机制，是以重力推动形成平稳、连续、竖直流动的液膜表面为“颗粒阱”，吸引颗粒主动向液膜表面运动（热泳与扩散泳）、其速度取决于气液界面两侧的热力学势差（动量浓度梯度、热量浓度梯度和质量浓度梯度），这与气液两相间的传递现象相一致，由此奠定了GLCA分离PM2.5的理论基础。并据此建立了GLCA传热传质界面气流边界层内PM2.5颗粒运动学模型，揭示了跟随气流运动的颗粒同时进行热泳、扩散泳“三元”速度叠加特征，掌握了边界层内颗粒轨迹计算方法，从而建立了以颗粒是否“落阱”（被液面吸收）为判据、直观表征PM2.5分离效率的数学模型。上述机理与模型研究得到了实验数据和工业现场试验验证。.项目取得的成果包括：期刊论文和国际会议论文13篇，申请发明专利4件（已获授权1件），获省科技进步三等奖1项，培养毕业博士生2名、硕士生3名。.研究成果之一“无含氟尾气排放的湿法磷酸工艺与氟硅酸加工方法”（已申请发明专利）为磷酸工业废气净化循环利用技术提供了重要基础并已具备产业化条件，2016年与企业合作开展工业性试验已初步取得良好结果，正在进一步扩大试验范畴、获取过程调控关键参数、优化工程与装备放大参数以及在线监测尾气PM2.5浓度等。预期2017年将获得更显著的成果。