高壓下不同載氣多原料超濃相氣力輸送機(jī)理及流動(dòng)特性研究

陳曉平　梁財(cái)　趙長(zhǎng)遂　龔欣　郭曉鐳

摘 要：為了獲得高壓濃相氣力輸送過程中不同粉體的輸送機(jī)理及流動(dòng)特性，對(duì)發(fā)料罐內(nèi)的流動(dòng)特性、不同粉體的輸送特性及含水率對(duì)流動(dòng)穩(wěn)定性的影響規(guī)律進(jìn)行實(shí)驗(yàn)研究并進(jìn)行數(shù)值模擬。引用先進(jìn)的陣列式靜電傳感器對(duì)粉體流動(dòng)過程的特征參數(shù)進(jìn)行監(jiān)測(cè)。結(jié)果如下：采用光纖顆粒濃度探針獲得了常壓上出料式發(fā)送罐內(nèi)提升管入口附近區(qū)域顆粒濃度分布，揭示了提升管入口附近區(qū)域氣固流動(dòng)結(jié)構(gòu)的變化規(guī)律。在高壓超濃相條件下進(jìn)行了不同含碳原料的氣力輸送實(shí)驗(yàn)研究，獲得了褐煤、無煙煤以及石油焦的輸送規(guī)律，發(fā)現(xiàn)了石油焦輸送過程中的結(jié)殼問題并提出了解決方法；通過褐煤中不同賦存形態(tài)的水分進(jìn)行分類研究，獲得了不同褐煤氣力輸送臨界水分含量。對(duì)工業(yè)規(guī)模級(jí)豎直上升管壓降進(jìn)行了研究，并對(duì)粉煤密相氣力輸送管路流型及其壓力信號(hào)特征分析，揭示了粉煤流動(dòng)穩(wěn)定性以及流型變化特性。對(duì)基于顆粒動(dòng)理學(xué)理論的雙流體模型進(jìn)行了修正，建立了描述常壓上出料式發(fā)送罐內(nèi)氣固流動(dòng)的數(shù)學(xué)模型，獲得了提升管入口附近區(qū)域顆粒濃度和速度分布規(guī)律。基于雙流體Euler-Euler方法，將k-ε-kp-εp湍流模型與顆粒動(dòng)理學(xué)理論相結(jié)合，對(duì)高壓超濃相粉體氣力輸送的氣固兩相流的全面力學(xué)分析，通過對(duì)氣固兩相流的動(dòng)力學(xué)參數(shù)的瞬態(tài)分布特征的理論分析，對(duì)原有數(shù)理模型進(jìn)一步的改進(jìn)和完善后，利用此模型對(duì)高壓超濃相輸送系統(tǒng)中水平管、彎管和垂直管建立了完善的一體化管道并進(jìn)行模擬計(jì)算。開發(fā)了基于陣列式靜電傳感器的多路相關(guān)速度測(cè)量系統(tǒng)，實(shí)現(xiàn)了顆粒局部平均速度的測(cè)量，并將其應(yīng)用于高壓濃相煤粉氣力輸送的過程監(jiān)測(cè)中，為提高氣力輸送效率和輸送穩(wěn)定性提供參考依據(jù)。

關(guān)鍵詞：高壓 濃相 氣力輸送 多原料 載氣 流動(dòng)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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