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

【摘要】：篦冷機(jī)是水泥熟料生產(chǎn)線的核心設(shè)備,回收熱量的多少和熱風(fēng)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(jì)算機(jī)模擬熟料的冷卻換熱,對(duì)生產(chǎn)具有一定的指導(dǎo)作用。但由于實(shí)際工況的復(fù)雜性和不確定性,并不能反映出目前篦冷機(jī)存在的問題,具有一定的局限性。本文采用縮小篦冷機(jī)進(jìn)行小型工程實(shí)驗(yàn)的方法,對(duì)不同篦下風(fēng)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(jìn)行冷態(tài)實(shí)驗(yàn)和熱態(tài)實(shí)驗(yàn),并對(duì)目前生產(chǎn)過程中篦冷機(jī)出現(xiàn)的篦縫過寬、粗細(xì)料離析、飛砂等不良現(xiàn)象進(jìn)行實(shí)驗(yàn)驗(yàn)證、分析。主要研究結(jié)論如下:(1)對(duì)不同粒徑熟料的測(cè)試中發(fā)現(xiàn),隨著熟料粒徑的變小,料層阻力逐漸增加。空隙率是料層阻力的最大影響因數(shù),采用歐根公式對(duì)篦冷機(jī)實(shí)際料層阻力進(jìn)行計(jì)算的方法,并不能準(zhǔn)確的估算出料層的阻力。通過對(duì)不同粒徑的熟料進(jìn)行反復(fù)實(shí)驗(yàn),歸納出了能夠比較準(zhǔn)確估算料層阻力的經(jīng)驗(yàn)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(shí)際生產(chǎn)中,設(shè)計(jì)篦板和匹配風(fēng)機(jī)時(shí)都應(yīng)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(shí)驗(yàn)得出飛砂料流態(tài)化速度為0.38m/s,較理論計(jì)算值偏小,并繪制出了ΔP~u曲線;采用阿基米德準(zhǔn)數(shù)計(jì)算的流態(tài)化速度和流態(tài)化極限速度,與實(shí)際測(cè)試值比較接近。(4)在一定范圍內(nèi),增加篦下風(fēng)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(fēng)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(fēng)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(duì)粗、細(xì)料離析的測(cè)試中發(fā)現(xiàn)Φ10-16mm+Φ20-31.5mm實(shí)驗(yàn)組冷卻換熱后的空氣溫度比Φ5-10mm+Φ20-31.5mm實(shí)驗(yàn)組溫度高出71℃。篦板縫隙和顆粒離析是造成冷卻空氣嚴(yán)重分布不均,二、三次風(fēng)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(hào)：1517411