电站脱硫系统防磨复合材料的制备工艺研究

发布时间：2018-11-23 07:03

【摘要】：湿法脱硫系统中的核心动力部件是循环浆液泵,服役环境恶劣。其中主要过流部件叶轮等在循环浆液中不停受到腐蚀、冲蚀以及汽蚀等问题,冲蚀磨损程度严重。根据目前金属叶轮普遍工作寿命较短的情况,使用耐磨复合材料替代金属材料制作叶轮,被认为是针对这一问题的低成本解决方案。环氧树脂基复合材料固化后力学性能良好,耐磨性强,固化收缩率小,是优良的一体成型以及涂覆材料。本文通过对实验室研发的混填颗粒环氧树脂基复合材料固化过程中的流变特性、固化反应以及固化后的力学性能研究,为其制定合适的成型工艺,用以解决电厂浆液泵的磨损问题。首先,对颗粒级配树脂基体固化过程进行化学流变学检测,确定固化过程中凝胶点温度;使用Castro和Macosko经验方程描述体系复合粘度同温度以及固化度变化关系,并与实际情况进行拟合,建立流变学模型;标明实际固化过程中体系复合粘度在200~800m Pa·s内的保持时间、温度范围以及合适的升温速率。由此得出适用于不同成型工艺的温度与时间参数,对实际操作提供理论指导。其次,对树脂基体的固化反应过程进行热流扫描(DSC),建立树脂体系的固化反应动力学模型,确定为自催化模型;通过模型描述了固化度与反应温度,反应速率以及反应活化能的关系;使用外推法求得体系阶梯固化的三个特征温度,优化了阶梯固化工艺;研究了混填颗粒及其表面改性对体系固化反应的影响,表明两种方式均不改变体系固化反应机理,混填颗粒会增大固化反应位阻延迟效应,而使用硅烷偶联剂的表面改性方法则可以改善这种情况。对固化反应中的温度参数、填料以及助剂进行研究,为实际工艺中的相关选择提供指导依据。最后,对固化成型后的试样进行热动态机械分析(DMA),通过力学模量及玻璃化温度转变点测量,对比了颗粒混填,表面改性对材料最终力学性能的影响。表明以上两种方式可以极大地提高树脂固化体系的弹性模量,增大材料的硬度。还验证了后固化处理以及提高阶梯固化温度处理对材料力学性能的影响,其效果并不明显,表明实验室目前使用的阶梯固化温度可以使体系进行较完全的固化。综上,通过不同热分析方式对体系固化过程进行研究,确定了较为合理的固化工艺参数,对比了不同工艺对成型复合材料力学模量的影响。基于以上研究,本文认为实验室研发的混填颗粒环氧树脂基复合材料是可以替代金属叶轮或进行表面涂覆的优良材料。
[Abstract]:Circulating slurry pump is the core power component of wet desulfurization system. The impeller, the main overflowing part, is corroded, eroded and cavitated continuously in the circulating slurry, and the erosion wear degree is serious. According to the condition that the working life of metal impeller is short at present, it is considered to be a low cost solution to solve this problem by using wear-resistant composite material instead of metal material to make impeller. Epoxy matrix composites have good mechanical properties, strong wear resistance and low shrinkage after curing, so they are excellent integrated molding and coating materials. In this paper, the rheological characteristics, curing reaction and mechanical properties of the hybrid particulate epoxy matrix composites developed by the laboratory were studied, and the appropriate molding process was established for them. It is used to solve the wear problem of slurry pump in power plant. Firstly, the curing process of grained resin matrix was tested by chemical rheology, and the gel point temperature was determined. Castro and Macosko empirical equations were used to describe the relationship between the complex viscosity and the temperature and curing degree, and the rheological model was established by fitting with the actual situation. The retention time, temperature range and appropriate heating rate of the composite viscosity in 200m / 800m Pa / s during the actual curing process were indicated. The temperature and time parameters suitable for different molding processes are obtained, which provide theoretical guidance for practical operation. Secondly, the curing reaction kinetics model of resin system was established by heat flux scanning (DSC), which was determined as the autocatalytic model. The relationship between curing degree and reaction temperature, reaction rate and reaction activation energy was described, and three characteristic temperatures of the system were obtained by extrapolation, and the step curing process was optimized. The effects of the mixed particles and their surface modification on the curing reaction of the system are studied. It is shown that neither of the two methods can change the curing mechanism of the system, and the effect of the steric resistance delay of the curing reaction will be increased by the mixed particles. The use of silane coupling agent surface modification method can improve this situation. The temperature parameters, fillers and auxiliaries in the curing reaction were studied to provide guidance for the selection of practical process. Finally, the thermodynamic mechanical analysis of the solidified sample was carried out. The mechanical modulus and glass transition point were measured by (DMA), and the effects of particle filling and surface modification on the final mechanical properties of the material were compared. The results show that the above two methods can greatly improve the elastic modulus of the resin curing system and increase the hardness of the material. The effect of post-curing treatment and raising step curing temperature on mechanical properties of materials is also verified. The effect is not obvious, which indicates that the step curing temperature used in laboratory can make the system solidify completely. In summary, the curing process of the system was studied by different thermal analysis methods, and the reasonable curing process parameters were determined, and the effects of different processes on the mechanical modulus of the composites were compared. Based on the above research, it is considered that the hybrid particle epoxy matrix composites developed by the laboratory can replace the metal impeller or be coated on the surface.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ323.5;TB332;X773

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