本文關(guān)鍵詞： 組合床 傳熱 關(guān)聯(lián)式　出處：《大連理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：流化—移動(dòng)組合床是將流化床和移動(dòng)床相結(jié)合,充分利用流化床的高效傳熱和移動(dòng)床的連續(xù)操作特性。本文通過(guò)實(shí)驗(yàn)研究和分析組合床的流體力學(xué)和傳熱特性。本研究首先以玻璃珠為物料進(jìn)行流體力學(xué)和傳熱特性實(shí)驗(yàn)研究,從流化狀態(tài)和傳熱系數(shù)來(lái)考察流化床的分級(jí)和傳熱效果。實(shí)驗(yàn)從顆粒粒徑、分級(jí)效率、床層高度、臨界流化氣速等因素方面來(lái)研究組合床中玻璃珠的流體力學(xué)特性。顆粒粒徑增大,臨界流化速度隨著增大,壓降隨床層高度增高而變大。隨操作氣速的增大,床層的分級(jí)效率先上升,達(dá)到一個(gè)最大值后下降。氣速在一定范圍內(nèi),隨氣速增高,床層的揚(yáng)析量成指數(shù)增長(zhǎng),但分級(jí)效率降低。在傳熱實(shí)驗(yàn)中,從氣速、空氣溫度、粒徑和床層高度等角度來(lái)考察氣固傳熱系數(shù)的變化。通過(guò)對(duì)流化-移動(dòng)組合床的傳熱過(guò)程正交分析得到氣-固傳熱的經(jīng)驗(yàn)關(guān)聯(lián)式：流化部分：移動(dòng)部分：在玻璃珠的流體力學(xué)實(shí)驗(yàn)基礎(chǔ)上進(jìn)行煤的干燥實(shí)驗(yàn)。從操作氣速、空氣溫度和床層移動(dòng)速率等方面研究煤的干燥過(guò)程。煤的干燥過(guò)程分為恒速干燥階段和降速干燥階段,床層的溫度在恒速干燥階段變化較小。隨操作氣速和空氣入口溫度的增加,組合床的干燥速率加快。并且在不同的溫度和氣速下,煤的平衡含水量發(fā)生改變。當(dāng)空氣溫度為120℃、流量為32m3/h時(shí),煤的臨界含水量在2%左右。
[Abstract]:Fluidized moving combined bed is a combination of fluidized bed and moving bed. Taking full advantage of the high efficiency heat transfer of fluidized bed and the continuous operation characteristics of moving bed, the hydrodynamics and heat transfer characteristics of the combined bed are studied and analyzed experimentally in this paper. Firstly, the hydrodynamics and heat transfer characteristics of the composite bed are studied experimentally with glass beads as the material. The classification and heat transfer effect of fluidized bed are investigated from fluidized bed state and heat transfer coefficient. The experimental results are as follows: particle size, fractionation efficiency, bed height, The hydrodynamic properties of glass beads in the combined bed are studied in terms of critical fluidization gas velocity and other factors. The particle size increases, the critical fluidization velocity increases, the pressure drop increases with the increase of bed height, and with the increase of operating gas velocity, The fractionation efficiency of the bed increased first, reached a maximum and then decreased. The gas velocity increased exponentially with the increase of the gas velocity, but the fractionation efficiency decreased. In the heat transfer experiment, the gas velocity, the air temperature, The change of gas-solid heat transfer coefficient was investigated from the angles of particle size and bed height. The empirical correlation of gas-solid heat transfer was obtained by orthogonal analysis of fluid-moving combined bed heat transfer process: fluidized part: moving part: in glass. On the basis of the hydrodynamic experiment of bead, the drying experiment of coal was carried out. The drying process of coal is studied in the aspects of air temperature and bed moving rate. The drying process of coal is divided into constant drying stage and decreasing drying stage. The drying rate of the combined bed increased with the increase of operating gas velocity and air inlet temperature, and the drying rate of the combined bed increased at different temperatures and gas velocities. When the air temperature is 120 鈩，

本文編號(hào)：1541777