本文關鍵詞： 痕量分離 整微板 塔板效率 氣含率 功率譜密度 解吸效率　出處：《青島科技大學》2015年碩士論文　論文類型：學位論文

【摘要】：塔設備是廣泛應用于煉油、化工等行業(yè)物質(zhì)分離的一種重要的氣液和液液傳質(zhì)設備。在痕量分離中,無論是對填料塔還是板式塔的開發(fā),都存在結(jié)構(gòu)復雜和生產(chǎn)成本高的缺點,所以研究者們開始尋找不使塔板效率降低同時又能使篩板結(jié)構(gòu)簡單的方法。因在痕量分離過程中,氣泡直徑大小對塔板效率的高低起著決定性的作用,所以提高分離效率的有效方法是破除較大氣泡,強化表面更新和增大兩相接觸面積。其中破除大氣泡最簡單直接的方法是在篩板上鋪設一層篩網(wǎng),即建立重整化微尺度篩板結(jié)構(gòu)�；谶@種結(jié)構(gòu),本文通過CFD模擬和實驗驗證的方法對整微板的結(jié)構(gòu)和流體力學性能進行了系統(tǒng)的研究。本文采用歐拉-歐拉雙流體模型構(gòu)建了非穩(wěn)態(tài)三維塔板氣液流場,通過對氣含率和開孔率等分析得出其最佳結(jié)構(gòu)：方形篩網(wǎng)的安裝高度為25mm,開孔率為55.7%為最佳；且單層篩網(wǎng)更適用于工業(yè)推廣應用；采用CFD-PBM耦合模型對整微板進行模擬分析,得出大、小氣泡群在塔內(nèi)的分布規(guī)律,且整微板中氣泡平均直徑僅為篩板的12%；通過對比兩種塔板的模擬結(jié)果,可以發(fā)現(xiàn)篩網(wǎng)能夠使氣相分布變得更為均勻,還消除了所在位置上的大旋渦,規(guī)整了氣相流動方向,這些改變都是有利于傳質(zhì)的。為了定量分析影響塔板效率的各參數(shù),本文選用空氣-水系統(tǒng)進行篩板和整微板的流體力學實驗測定,并對氣泡特性進行了一系列的研究,實驗結(jié)果表明整微板的最優(yōu)結(jié)構(gòu)是：篩網(wǎng)的安裝高度為25mm,孔徑為5目。并與篩板做了對比,結(jié)果表明：整微板的平均濕板壓降達到0.243kPa,比篩板高出44個百分點,導致能耗較大；整微板的平均氣泡直徑為5.16mm,僅為篩板的15%,與模擬值基本吻合；整微板的氣含率較篩板平均高出3.28%；整微板中的壓力波動較為平穩(wěn),且功率譜密度圖也反映了小氣泡能更好的保持其形態(tài),破碎頻率遠遠低于篩板,對塔的操作狀態(tài)有較大程度的改善。本文選取SO2的解吸實驗來分析篩板和整微板的傳質(zhì)效率。實驗結(jié)果表明：普通解吸時,同等條件下,整微板的解吸效率為86.85%,是篩板的1.87倍；痕量解吸時,整微板的解吸效率仍能保持在50%以上,遠遠大于篩板的解吸效率,且解吸效果良好,能將SO2濃度降至20mg·L-1以下,遠低于篩板的解吸極限。故在痕量分離過程中,整微板具有很好的應用前景。
[Abstract]:Column equipment is an important gas-liquid and liquid-liquid mass transfer equipment widely used in oil refining, chemical industry and other industries. In trace separation, both the development of packed column and plate column have the disadvantages of complex structure and high production cost. So researchers started looking for ways not to reduce the efficiency of trays and to make the structure of sieve plates simple, because in trace separation, bubble diameters play a decisive role in the efficiency of trays. So the effective way to improve the separation efficiency is to break down the larger bubble, to strengthen the surface renewal and to increase the contact area of two phases. The simplest and most direct way to break the big bubble is to lay a screen net on the sieve plate. That is, to establish a renormalization microscale sieve plate structure, based on this structure, In this paper, the structure and hydrodynamic properties of microplates are systematically studied by means of CFD simulation and experimental verification. In this paper, the gas-liquid flow field of unsteady three-dimensional trays is constructed by using Euler-Euler two-fluid model. Through the analysis of gas holdup and opening rate, the optimum structure is obtained: the installation height of square screen is 25mm, the opening ratio is 55.7%, the single-layer screen is more suitable for industrial application, and the CFD-PBM coupling model is used to simulate the microplate. The distribution of large and small bubble groups in the tower is obtained, and the average diameter of the bubbles in the whole plate is only 12 of that of the sieve plate. By comparing the simulation results of the two trays, it is found that the gas phase distribution can be more uniform by the sieve mesh. In order to quantitatively analyze the parameters affecting the efficiency of the tray, the large vortex in the position is eliminated and the flow direction of the gas phase is regularized, and these changes are beneficial to mass transfer. In this paper, the air-water system is used to measure the hydrodynamics of sieve plate and microplate, and a series of studies on the bubble characteristics are carried out. The experimental results show that the optimum structure of the microplate is that the installation height of the screen is 25mm and the aperture is 5 meshes. The results show that the average wet plate pressure drop of the microplate is 0.243 KPA, which is 44 percentage points higher than that of the sieve plate, which results in higher energy consumption. The average bubble diameter of the microplate was 5.16 mm, which was only 15 mm of the sieve plate, which basically coincided with the simulated value. The gas holdup of the whole microplate was 3.28 mm higher than that of the sieve plate, and the pressure fluctuation in the whole plate was more stable. And the power spectral density diagram also shows that the small bubble can better maintain its shape, the breaking frequency is much lower than that of the sieve plate. In this paper, the mass transfer efficiency of sieve plate and microplate is analyzed by SO2 desorption experiment. The results show that under the same conditions, the desorption efficiency of the whole plate is 86.85, which is 1.87 times of that of the sieve plate. For trace desorption, the desorption efficiency of microplate is still above 50%, which is much higher than that of sieve plate, and the desorption efficiency is good, and the concentration of SO2 can be reduced to less than 20mg 路L ~ (-1), which is far lower than the desorption limit of sieve plate, so in the process of trace separation, The microplate has a good application prospect.
【學位授予單位】：青島科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ053.5

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