粉煤灰采集分级分离装置的数值模拟与实验研究

发布时间：2018-11-20 20:20

【摘要】：大宗工业废弃物的综合利用是解决因工业固体废料堆存而带来环境污染和安全隐患的治本之策。发电厂的粉煤灰除了一般意义的粉尘空气污染以外,粉煤灰因其中含有微量的重金属和极少量的放射性物质,在外界环境的长期作用下还会深入地层对水和土壤造成严重污染,且容易发生地质灾害。目前粉煤灰的传统处理方法已经不再适合当前的环保要求。粉煤灰中含有多种有用物质,如微玻璃珠、高铝粉、炭粉等,有效采集并分离这些物质可以大幅提高粉煤灰的经济价值。粉煤灰的综合利用不仅能使得粉煤灰变废为宝,而且对于保护环境有着更为重要的意义。本文重点研究传统干式气流分选粉煤灰方法中固体颗粒与气体组成的两相流流动问题。在两相流分级的理论模型与经验模型的基础上,主要针对10μm、50μm、 250μm三种不同粒径固体颗粒在空气中的运动建立了更加完善的数学模型和进行了相关的后期实验研究。在数值计算方面,基于流体力学理论,系统性、条理性地推导和演绎了两相流的控制方程,并利用MATLAB软件,分别模拟出三种固体颗粒受各种不同力的影响水平,同时模拟出三种不同粒径的颗粒在气流中处于悬浮状态时分选速度分别为0.3m/s、1.38m/s、2.46m/s。本文还利用Fluent软件模拟了三种不同喷射流流量下的流化域形状,得出最佳喷射流量为1.5m3/h。本研究中的粉煤灰采集分级分离实验装置根据气流分选原理而自行设计。在实验研究方面,设计制作了实体装置模型,该部分主要针对系统模型的工作原理、结构设计、模型制作过程进行详细讨论；实验结果表明,分选效果明显,第一级分离出的玻璃微珠的比例很高,第二级分选出的粉煤灰的细度达到了粉煤灰二级国家标准。第三极分级口的细度达到了粉煤灰三三级国家标准。然后将模拟结果与实验数据进行了比较,验证相关模型的可靠性、准确性,对优化分级器结构,提高分级器分选效率具有重要的意义。
[Abstract]:The comprehensive utilization of industrial waste is the solution to the environmental pollution and safety hidden trouble caused by industrial solid waste storage. In addition to dust air pollution in general sense, fly ash in power plants, because it contains small amounts of heavy metals and very small amounts of radioactive material, will also cause serious pollution to water and soil under the long-term action of the external environment. And prone to geological disasters. At present, the traditional treatment method of fly ash is no longer suitable for the current environmental protection requirements. Fly ash contains a variety of useful substances, such as micro-glass beads, high-alumina powder, carbon powder, etc. The effective collection and separation of these substances can greatly improve the economic value of fly ash. The comprehensive utilization of fly ash can not only turn fly ash into a treasure, but also have more important significance for environmental protection. This paper focuses on the two-phase flow problem of solid particle and gas composition in the traditional dry air separation method of fly ash. Based on the theoretical model and empirical model of two-phase flow classification, a more perfect mathematical model for the movement of three kinds of solid particles with different particle sizes (10 渭 m 50 渭 m and 250 渭 m) in air was established and the related later experiments were carried out. In the aspect of numerical calculation, the governing equations of two-phase flow are deduced and deduced systematically and methodically based on the theory of fluid dynamics, and three kinds of solid particles affected by different forces are simulated by using MATLAB software, respectively. At the same time, it is simulated that the separation rate of three kinds of particles with different particle size is 0.3m / s / s 1.38m / s ~ (2.46) m / s respectively when they are suspended in the air flow. The flow domain shapes of three different jet flows are simulated by using Fluent software, and the optimum flow rate is 1.5 m3 / h. According to the principle of airflow separation, the experimental device for collecting and classifying fly ash in this study is designed by itself. In the aspect of experimental research, the solid device model is designed and made. This part mainly discusses the working principle, structure design and model making process of the system model. The experimental results show that the separation effect is obvious, the proportion of the glass beads separated in the first stage is very high, and the fineness of the fly ash separated from the second stage is up to the national standard of the second grade of fly ash. The fineness of the third pole classifier has reached the national standard of fly ash. Then the simulation results are compared with the experimental data to verify the reliability and accuracy of the related models. It is of great significance to optimize the classifier structure and improve the sorting efficiency of classifier.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X773

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