本文選題：炭素電極　切入點：焙燒爐　出處：《湘潭大學(xué)》2015年碩士論文

【摘要】：我國炭素電極生產(chǎn)屬于高能耗產(chǎn)業(yè),炭素焙燒是其生產(chǎn)過程中重要熱處理工序之一,對其進行結(jié)構(gòu)及運行操作參數(shù)優(yōu)化,實現(xiàn)節(jié)能降耗潛力巨大。鑒于炭素焙燒熱工過程的復(fù)雜性,利用數(shù)值模擬方法對炭素焙燒爐的熱工過程進行系統(tǒng)研究,改善焙燒爐運行條件具有重要意義。針對上述中炭素電極塊溫度分布不均、焙燒周期長等問題,研究了炭素焙燒爐結(jié)構(gòu)和操作參數(shù)對其熱工過程的影響。主要工作和結(jié)論如下:1)以某炭素廠12室倒焰式炭素焙燒爐為研究對象,首先對其開展燃燒試驗和熱平衡分析,發(fā)現(xiàn)焙燒爐內(nèi)熱損主要是排煙損失,超過了69%,這導(dǎo)致焙燒爐熱效率低下,延長了焙燒周期。通過對實際物理模型進行合理的簡化和假設(shè),建立了炭素焙燒爐熱工過程的數(shù)學(xué)模型。基于FLUENT軟件,根據(jù)炭素焙燒爐焙燒工藝的特點,建立了炭素焙燒爐熱工過程仿真系統(tǒng)。2)數(shù)值模擬研究了初始工況下焙燒爐內(nèi)速度場、溫度場、濃度場和炭素電極塊升溫曲線及最終焙燒溫度分布規(guī)律。模擬結(jié)果表明:爐內(nèi)的高溫煙氣流主要向著下降火道出口處負壓方向流動,對爐內(nèi)其他區(qū)域帶動作用較少;在一個焙燒周期內(nèi),造成炭素電極塊實際焙燒升溫速率始終滯后于目標升溫速率,低于目標焙燒溫度約200℃;同時炭素電極塊在豎直方向上溫度分布不均勻,沿高度遞增方向,炭素電極塊內(nèi)溫度逐漸升高,最大溫差值超過200℃。3)通過在炭素電極塊下方采用添加一條支火道補償加熱的方法,減小炭素電極塊在豎直方向的溫差,模擬結(jié)果表明:炭素電極塊達到相同焙燒平均溫度時,改進后的炭素電極塊的焙燒升溫時間更短,節(jié)省了15.35小時,相當于節(jié)省約655kg標準煤;同時炭素電極塊上下溫差明顯縮小,最大溫差小于70℃。4)在火道結(jié)構(gòu)優(yōu)化的基礎(chǔ)上,進一步分析了助燃空氣溫度、火道出口負壓值等因素對炭素電極塊升溫及溫度均勻性的影響。隨著助燃空氣溫度的增加,炭素電極塊的焙燒溫度得到提升,且其內(nèi)部的溫差有所降低,均勻性更好。負壓為3Pa左右時,火道內(nèi)煙氣平均溫度較高,炭素電極塊內(nèi)溫度較為均勻。
[Abstract]:Carbon electrode production in China belongs to high energy consumption industry. Carbon roasting is one of the important heat treatment processes in the production process. The structure and operation parameters of carbon electrode are optimized. In view of the complexity of the thermal process of carbon roasting, the thermal process of carbon roaster is studied systematically by numerical simulation. It is of great significance to improve the operation conditions of roasting furnace. In view of the above problems, such as uneven temperature distribution of carbon electrode block and long roasting period, etc. The influence of the structure and operation parameters of carbon roaster on its thermal process was studied. The main work and conclusions are as follows: 1) taking the 12 chamber reverse flame type carbon roaster in a carbon plant as the research object, the combustion test and thermal equilibrium analysis were carried out. It is found that the heat loss in the roasting furnace is mainly smoke exhaust loss, which exceeds 69, which leads to the low thermal efficiency of the calciner and prolongs the roasting period. The actual physical model is reasonably simplified and hypothesized. The mathematical model of the thermal process of carbon roaster was established. Based on FLUENT software and according to the characteristics of calcination process of carbon roaster, the simulation system of thermal process of carbon roaster was established. The velocity field in the calciner under the initial working condition was studied by numerical simulation. The temperature field, concentration field, heating curve of carbon electrode block and the distribution law of final calcination temperature. The simulation results show that the flow of high temperature smoke in the furnace is mainly towards the negative pressure direction at the outlet of the falling fire channel, and it has little driving effect on other regions of the furnace. During a roasting period, the actual heating rate of the carbon electrode block always lags behind the target heating rate, which is about 200 鈩，

本文編號：1671669