高压下不同载气多原料超浓相气力输送机理及流动特性研究

陈晓平　梁财　赵长遂　龚欣　郭晓镭

摘 要：为了获得高压浓相气力输送过程中不同粉体的输送机理及流动特性，对发料罐内的流动特性、不同粉体的输送特性及含水率对流动稳定性的影响规律进行实验研究并进行数值模拟。引用先进的阵列式静电传感器对粉体流动过程的特征参数进行监测。结果如下：采用光纤颗粒浓度探针获得了常压上出料式发送罐内提升管入口附近区域颗粒浓度分布，揭示了提升管入口附近区域气固流动结构的变化规律。在高压超浓相条件下进行了不同含碳原料的气力输送实验研究，获得了褐煤、无烟煤以及石油焦的输送规律，发现了石油焦输送过程中的结壳问题并提出了解决方法；通过褐煤中不同赋存形态的水分进行分类研究，获得了不同褐煤气力输送临界水分含量。对工业规模级竖直上升管压降进行了研究，并对粉煤密相气力输送管路流型及其压力信号特征分析，揭示了粉煤流动稳定性以及流型变化特性。对基于颗粒动理学理论的双流体模型进行了修正，建立了描述常压上出料式发送罐内气固流动的数学模型，获得了提升管入口附近区域颗粒浓度和速度分布规律。基于双流体Euler-Euler方法，将k-ε-kp-εp湍流模型与颗粒动理学理论相结合，对高压超浓相粉体气力输送的气固两相流的全面力学分析，通过对气固两相流的动力学参数的瞬态分布特征的理论分析，对原有数理模型进一步的改进和完善后，利用此模型对高压超浓相输送系统中水平管、弯管和垂直管建立了完善的一体化管道并进行模拟计算。开发了基于阵列式静电传感器的多路相关速度测量系统，实现了颗粒局部平均速度的测量，并将其应用于高压浓相煤粉气力输送的过程监测中，为提高气力输送效率和输送稳定性提供参考依据。

关键词：高压 浓相 气力输送 多原料 载气 流动特性

Abstract：In order to obtain conveying mechanisms and flow characteristics of dense-phase pneumatic conveying at high pressure， experimental study and numerical simulation on discharge characteristics of blow tank， conveying experiments of different carbonaceous powders and moisture content were performed. Advanced electrostatic sensor arrays were used to monitor powder flow characteristic parameters during conveying process. The results are as follows： an optical fiber particle concentration probe was utilized to obtained particle concentration distribution near the inlet of top discharge feeding hopper under normal pressure， which reveals the variation regularity of gas-solid flow structure in the region near the lift pipe inlet. Under the condition of high-pressure ultra-dense phase， different carbonaceous particles of lignite， anthracite and petroleum coke pneumatic conveying experiments were conducted to find their conveying regularities， and crusting and its solution were found during conveying petroleum coke； classifying study on various modes of occurrence of water in lignite got different critical moisture content during pneumatic conveying. Pressure drop of vertical lifting pipe of industrial scale was studied， and the flow pattern of dense-phase pulverized coal in pneumatic pipe and its characteristics on pressure signal was analyzed. Based on the two-fluid model of particle kinetic theory was amended to establish a mathematical model describing the material type sent out on the solid flow tank pressure，get the riser near the entrance area of particle concentration and velocity distribution.Based on the two-fluid Euler-Euler method， the k-ε-kp-εp turbulence model and the particle kinetic theory by combining ultra- dense high-pressure phase of comprehensive mechanical pneumatic conveying of powders phase flow analysis by gas-solid distribution of transient two-phase theory of kinetic parameters of the analysis， the original mathematical model to further improve and refine the use of this model for ultra- high pressure dense phase conveying systems level， bends and vertical pipes to establish a sound integrated pipeline and simulation.Developed a multi-channel correlation velocity measurement system based on electrostatic sensor array，to achieve local average particle velocity measurements， and apply process high pressure dense phase pneumatic conveying of pulverized coal monitoring.

Key Words：High-pressure；Dense-phase；Pneumatic conveying；Carbonaceous powder；Carrier gas；Flow characteristics

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