基于流化床反应器SiCl4氯氢化过程流化行为及热质传递特性研究

Hydrochlorination process is the most promising hydrogenation technology for the conversion of silicon tetrachloride (STC) to trichlorosilane (TCS), which is usually carried out in a fluidized bed reactor (FBR) of metallurgical silicon. The cost of ultra-pure silicon production by Siemens process can reduce effectively by means of the hydrochlorination reaction. However, enhancing the fluidization stability in FBR and increasing conversion rate and ratio are the main challenges for the hydrochlorination process. The present proposal can provide important base of theory for those by investigation on multi-phase fluid dynamics and synergistic study of characteristics of heat and mass transfer in the hydrochlorination process in the FBR. The start of the proposal is to develop a multi-phase fluid dynamics model in the FBR. The module of heat transfer is incorporated in the above fluid dynamics model based on flow field in the FBR. By application of the developed multi-phase fluid dynamic model coupled with the heat transfer module, the time-varying regularity of flow field, temperature profile, pressure field and residence time distribution can be investigated with silicon particle changing (consumption and addition). And the internal relations between continuous phase (gas phase) and discrete phase (solid phase), multiphase fluid motion and heat transfer are also established. Then, the heat and mass transport-kinetic model under multi-physics field for the hydrochlorination process can be developed by coupling population balance model (PBM) and Chemical kinetic model (CHEMKIN). By application of the developed model, the time-varying regularity of residence time distribution, the variation of the size of fluidized dead zone and the characteristics of heat and mass transfer can be investigated with silicon particle changing (consumption and addition). Furthermore, the conversion rate and ratio of STC can be predicted, and the synergistic action mechanism between the characteristics of heat and mass transfer and kinetics is also revealed through the above analytical studies. By the study of the present proposal, the interesting results can be used to provide the new ideas and approaches for the development of new equipment and the development of operation control technology for the hydrochlorination process.

流化床反应器（FBR）氯氢化技术是目前多晶硅领域SiCl4（STC）制备SiHCl3（TCS）最具前景的氢化技术，可有效降低西门子法多晶硅生产成本。然而，增强FBR流态化稳定性、提高STC转化速率和转化率是当前遇到的技术瓶颈，FBR流体力学及热质传递特性协同研究是解决该技术瓶颈的重要理论基础。本项目从建立FBR流体力学模型出发，耦合传热模型，研究流场、温度场、压力场及硅颗粒粒度分布的时变规律，建立起连续相（气相）与离散相（固相）、流体运动与热量传递的内在联系。引入粒群衡算模型（PBM）和反应动力学，构建FBR热质传递-动力学模型，获得硅颗粒动态变化（消耗和新加）物料停留时间、流化死区大小及热质传递特性变化规律，预测STC转化速率和转化率，阐明FBR床层热质传递特性与化学反应协同作用机制。通过本项目研究成果，为FBR氯氢化工艺新设备开发与操控技术的研发提供新思路和新方法。

流化床反应器（FBR）SiCl4氯氢化技术是目前多晶硅领域SiCl4制备SiHCl3最具前景的氢化技术，然而，当前主要的技术瓶颈在于如何有效地增强FBR流态化稳定性，提升SiCl4转化速率和效率。本项目以SiCl4氯氢化过程为研究对象，从增强FBR流态化稳定性，提升SiCl4转化率和效率角度出发，系统研究了不同流化阶段的FBR床层流型特征及热质传递特性，揭示了FBR床层硅颗粒输运机理；采用密度泛函理论，提出了SiCl4氯氢化过程微观反应机理，阐明了FBR床层热质传递特性与化学反应协同作用机制。研究取得如下成果：1) 根据SiCl4氯氢化过程气-固两相流行为特点，建立了描述流化床反应器氯氢化过程气-固两相流的欧拉-颗粒流数学模型；2) 基于所建立的欧拉-颗粒流模型开展系统数值模拟研究，并将模拟所得最大床层膨胀高度与经验计算理论值比较，验证了数学模型及求解方法的准确性；3) 耦合传热模型，研究了流场、温度场、压力场及硅颗粒粒度分布的时变规律，建立了连续相（气相）与离散相（固相）、流体运动与热量传递的内在联系；4) 阐明了SiCl4氯氢化过程的微观反应机理，构建了FBR热质传递-动力学模型，预测获得了SiCl4转化速率和转化率，形成了基于SiCl4氯氢化过程微观反应机理FBR调控机制。通过本项目研究成果，为FBR氯氢化工艺新设备开发与操控技术的研发提供新思路和新方法。项目执行期，发表学术论文9篇，其中SCI检索7篇，EI检索2篇；申请国家发明专利2项，授权实用新型专利1项；获云南省自然科学二等奖1项；晋升高级职称2人次，项目负责人入选云南省高层次人才培养支持计划“青年拔尖人才”、昆明市“春城计划”高层次人才青年人才和昆明市中青年学术和技术带头人后备人才，正培养物理学专业和材料与化工专业硕士研究生5名。

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