本文關(guān)鍵詞： 篦冷機 料層阻力 流態(tài)化 冷卻 換熱　出處：《西南科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：篦冷機是水泥熟料生產(chǎn)線的核心設備,回收熱量的多少和熱風品位的好壞,直接影響著整條窯系統(tǒng)的穩(wěn)定性和能耗的高低。目前,大部分研究都集中于通過計算機模擬熟料的冷卻換熱,對生產(chǎn)具有一定的指導作用。但由于實際工況的復雜性和不確定性,并不能反映出目前篦冷機存在的問題,具有一定的局限性。本文采用縮小篦冷機進行小型工程實驗的方法,對不同篦下風速、不同熟料粒徑、不同料層厚度下的料層阻力和冷卻換熱情況,分別進行冷態(tài)實驗和熱態(tài)實驗,并對目前生產(chǎn)過程中篦冷機出現(xiàn)的篦縫過寬、粗細料離析、飛砂等不良現(xiàn)象進行實驗驗證、分析。主要研究結(jié)論如下:(1)對不同粒徑熟料的測試中發(fā)現(xiàn),隨著熟料粒徑的變小,料層阻力逐漸增加�？障堵适橇蠈幼枇Φ淖畲笥绊懸驍�(shù),采用歐根公式對篦冷機實際料層阻力進行計算的方法,并不能準確的估算出料層的阻力。通過對不同粒徑的熟料進行反復實驗,歸納出了能夠比較準確估算料層阻力的經(jīng)驗公式。(2)在料層高度方向上,料層阻力分布并不相同,底部料層的阻力大于上部相同厚度的料層,并找到了相關(guān)的兩方面原因。實際生產(chǎn)中,設計篦板和匹配風機時都應考慮。(3)飛砂料的流態(tài)化特征完全符合氣固系統(tǒng)的非均一流態(tài)化,實驗得出飛砂料流態(tài)化速度為0.38m/s,較理論計算值偏小,并繪制出了ΔP~u曲線;采用阿基米德準數(shù)計算的流態(tài)化速度和流態(tài)化極限速度,與實際測試值比較接近。(4)在一定范圍內(nèi),增加篦下風速有利于空氣與熟料的換熱。熟料Φ20-31.5mm、溫度850℃的條件下,風速1.17m/s增加至1.29m/s,有利于熟料的換熱,超過1.29m/s后,作用不再明顯;熟料顆粒的粒徑是影響綜合換熱系數(shù)的重要因數(shù),粒徑越小,換熱越快。但冷卻初始階段,熟料表層溫度高,與冷卻空氣的溫差較大,冷卻速率基本相同。(5)在篦板通風面積2.48%、熟料Φ20-31.5mm、料層200mm的條件下,3mm篦縫造成熟料冷卻速度明顯降低,空氣溫度下降31℃;對粗、細料離析的測試中發(fā)現(xiàn)Φ10-16mm+Φ20-31.5mm實驗組冷卻換熱后的空氣溫度比Φ5-10mm+Φ20-31.5mm實驗組溫度高出71℃。篦板縫隙和顆粒離析是造成冷卻空氣嚴重分布不均,二、三次風溫度偏低的最主要原因。
[Abstract]:Grate cooler is the core equipment of cement clinker production line. The quantity of heat recovered and the grade of hot air directly affect the stability and energy consumption of the whole kiln system. Most of the research is focused on simulating the cooling and heat transfer of clinker by computer, which can guide the production to some extent. However, because of the complexity and uncertainty of the actual working conditions, it can not reflect the problems existing in the grate cooler at present. There are some limitations. In this paper, the resistance and cooling heat transfer of the material layer under different grate wind speed, different clinker particle size and different layer thickness are studied by using the method of small-scale engineering experiment with a reduced grate cooler. The cold and hot experiments were carried out respectively, and the bad phenomena such as too wide grate gap, coarse and fine material segregation, flying sand and so on, which appeared in the grate cooler in the current production process, were verified. The main conclusions are as follows: (1) in the test of clinker with different particle size, it is found that the resistance increases with the decrease of clinker particle size, and the porosity is the biggest influence factor of feed layer resistance. The method of calculating the actual layer resistance of grate cooler by using the Eucan formula can not accurately estimate the resistance of the material layer. Through repeated experiments on the clinker with different particle sizes, The empirical formula for estimating the resistance of the material layer accurately is concluded. (2) in the direction of the height of the material layer, the resistance distribution of the layer is different, and the resistance of the bottom layer is greater than that of the upper layer of the same thickness. Two related reasons have been found. In practical production, the fluidization characteristics of fly sand materials should be considered when designing grate plate and matching fan. The fluidization characteristics of fly sand completely accord with the heterogeneous fluidization of gas-solid system. The experimental results show that the fluidization rate of fly sand is 0.38 m / s, which is smaller than that of the theoretical calculation, and the 螖 Pu curve is drawn, and the fluidization velocity and fluidization limit velocity calculated by Archimedes number are close to the actual measured values in a certain range. Under the condition of 桅 20-31.5 mm, temperature 850 鈩，

本文編號：1517411