多喷嘴对置式Fenton脱硝反应器的液滴对撞混合反应机理研究

During Fenton reaction, strong oxidative free radicals are produced and then rapidly recombined, resulting in a loss of H2O2. To solve this problem, a a droplet head-on collision reactor for removal of NO form coal-fired flue gas by using Fenton reagent solution is proposed. The free radicals are produced and simultaneously react with NO, thus reducing the H2O2 loss. An experimental setup will be established to systematically investigate the changes in droplet shapes and in the concentrations inside droplets during droplet collision. Several crucial issues in the three-dimensional simulation on two-phase flow field using lattice Boltzmann (LBM) are expected to be solved combining simulation and experimental results. The effects of on-head droplet collision on mixing intensification inside droplet for droplet swarm is revealed. An experimental setup and corresponding method will be achieved using a confocal Raman microscope and micro fluidic chips to measure the concentration distribution inside a droplet as function of NO removal reaction time. The effect of NO removal reaction on the NO mass transfer in liquid is investigated. The three-dimensional simulation on the droplet head-on collision reactor will be carried out using Eular-Eular model with the initial values obtained by LBM. The main parameters of reactor are optimized by simulation results. Based on the optimized result, a droplet head-on collision reactor is developed and the corresponding experimental system for removal of NO is established. The effects of main process parameters on NO removal are systematically studied. The promotional effect of droplet swarm collision on NO removal is further understood. This project aims at providing theoretical and experimental guidance for a high-efficiency, low-cost, environmentally friendly NO removal method using Fenton reagent solution.

本项目提出基于液滴对撞混合的Fenton脱硝反应器，自由基产生即反应，减少现有反应器中由于自由基湮灭造成的H2O2损失。搭建两液滴对撞的微流控实验系统，系统研究液滴对撞过程中液滴形态变化及液滴内液体混合的规律。基于 LBM方法，结合两相流场测试，攻克多液滴对撞混合三维流场模拟中的诸多难点，揭示多液滴对撞混合机理（关键科学问题）。建立基于微流控芯片和共焦显微拉曼光谱仪的液滴内液体浓度变化的测量方法，研究Fenton反应强化NO液相传质的规律。进而将LBM计算结果作为初始参数，采用 Eular-Eular模型对反应器进行三维数值模拟和优化。在此基础上，搭建Fenton脱硝反应装置，系统研究各参数对脱硝反应的影响，深入理解多液滴对撞混合对Fenton反应脱硝的影响规律。本项目致力于为高效、低成本、环境友好的Fenton脱硝反应技术奠定理论和技术基础。

我国NOx污染情况严重、防治形势依旧严峻。本课题围绕着高效、低能耗、绿色的烟道气脱硝方法，从反应器、吸收剂、系统优化三个方面进行了系统研究。搭建了基于微流控芯片和共焦显微拉曼光谱的微流控试验系统，实现了高精度的微流体流场测量。建立了拉曼激光最大局部温升关联式，通过优化设计减小了局部温升造成的测量误差。研制了原位阳极键合实验装置，结合大尺度原子模拟和拉曼光谱应力测量，发现硅-玻璃键合区域存在80 MPa的拉应力，玻璃界面形成的氧化层是无定形的SiO2。建立了格子玻尔兹曼两相流模拟计算方法，模拟液滴运动及拓扑形态变化，并与基于高速摄像的实验结果相对照，发现决定液滴破裂的临界毛细管数受液滴周围流场的影响。提出基于中空纤维膜和H2O2吸收液的燃煤电厂烟道气中NO高效消除方法，采用在H2O2水溶液中添加NaCl提高NO的溶解度。为降低膜反应器的投资成本，提出一种先富集烟道气中的NO再通过中空纤维膜化学吸收的工艺，可同时副产KNO3化肥，投资成本是目前商业SCR脱硝工艺的28.8%，脱硝运行成本是目前Fenton反应脱硝的35.8%。针对垃圾发电厂烟道气含尘高、杂质多、对SCR的催化剂毒化强等问题，制备了吡啶改性的活性碳催化剂，室温下脱硝效率可达87% ，脱硝投资成本为SCR的85%，运行成本仅为SCR方法的9.7%-23.6%。在研究过程中，将膜气吸收方法推广至烟道气CO2的脱除，制备了超疏水无机中空膜， CO2的解吸能耗比现有的基于有机胺化学方法降低了33.8%，且同时实现了SO2的高效脱除。本项目的研究为高效、低成本、环境友好的烟道气脱硝技术奠定了理论和技术基础。