發(fā)布時間：2018-05-15 12:36

  本文選題：多級進氣 + 光生物反應器�。� 參考：《中國海洋大學》2015年碩士論文

【摘要】：微藻在生物能源、環(huán)境保護、食品、保健品及醫(yī)藥等領域具有巨大的潛在應用價值。然而微藻培養(yǎng)的反應器性能不佳一直制約著微藻規(guī)模化發(fā)展。傳統(tǒng)光生物反應器的優(yōu)化設計及放大方法研發(fā)周期長,成本大,不能全面研究反應器內部的流場特性。近年利用計算流體力學(CFD)進行微藻培養(yǎng)光生物反應器研究盡管有很多彌補傳統(tǒng)方法的優(yōu)點,但因剛剛興起仍存在大量空白。本文針對微藻培養(yǎng)領域主流的平板式光生物反應器,在前人基礎上提出了多級進氣多節(jié)隔板反應器的結構設想,并利用CFD技術對該新型反應器的混合、傳質和傳光特性進行了相對系統(tǒng)研究,具體結果如下。首先,采用ANSYS Fluent商業(yè)軟件,構建了多級進氣多節(jié)隔板平板式反應器計算模型,采用Eulerian-Eulerian多相流模型和PBM模型進行耦合模擬計算,模擬結果與實驗測量結果對比驗證了本文所建立模擬模型的可行性與可靠性。多級進氣反應器上段和中段隔板局部氣含率、局部液相矢量速度受通氣率的影響較大,其下段性能參數受通氣率的影響較�。浩渫膭幽茉谏簠^(qū)呈雙峰結構分布,在降液區(qū)湍動能分布較為平緩。而后,通過CFD模擬計算對比了普通(A)、多節(jié)隔板(B)、多級進氣多節(jié)隔板(C)三種反應器的流場流動與傳質特性。結果表明,在一定的通氣率下多級進氣反應器在氣含率、液體平均速度、湍動能、液相傳質系數等性能評價參數較前兩種反應器分別有很大提高,其中通氣率在0.8 vvm時,反應器C中的氣含率較反應器A、B分別提升52.63%和39.11%,通氣率在0.4 vvm和0.6 vvm時,反應器C的kLa值較反應器B分別提高36.16%和11.27%。進而,利用多相流模型和PBM模型耦合的方法,對影響該新型反應器混合傳動、傳質性能的氣泡特性進行了進一步的研究。反應器氣泡直徑分布等氣泡特性參數結果表明,在反應器高度390 mm上,反應器C的Bin-0體積分數較反應器B降低了32.79%：反應器B內大于6 mm氣泡直徑體積占總體積分數為8.58%,而反應器C為0.54%。上述結果表明反應器C能有效降低氣泡聚并,其中氣泡分布良好,這將有利于相間傳質。結合CFD模擬計算結果與藻類傳光規(guī)律,本文對比分析了三種反應器的傳光特性。結果表明,反應器C較反應器B增加了反應器內光照方向徑向混合強度,反應器C較反應器B在光區(qū)的徑向速度提高了28.25%,在光區(qū)平均停留的時間有所縮短,光暗循環(huán)的周期也相對比反應器B縮短了]9.63%,加快反應器內微藻的在光區(qū)和暗區(qū)的光暗循環(huán)頻率,加快了微藻閃光效應,有助于微藻生長。最后,通過CFD模擬對反應器C的內部結構參數(隔板的位置(Ar/Ad)、隔板上沿距液面的距離(h0)和隔板間隙的長度(D))進行了優(yōu)化分析。結果表明,液相體積傳質系數和光區(qū)的徑向速度隨Ar/Ad值的增大而降低,整體混合情況在Ar/Ad為0.5時效果較好；整體的混合性能和光區(qū)的徑向速度隨h0增加而增加,當ho為40 mm時反應器的傳質性能較好；隨著隔板間隙的距離增加,ATK和光區(qū)徑向速度逐漸增加,而反應器的傳質性能在隔板間隙為15mm時達到最大。綜上所述,反應器C較其他兩種反應器在混合、傳動和傳質性能上有很大的提升,降低反應器內氣泡的聚并現(xiàn)象,優(yōu)化氣泡分布,提高閃光效應。反應器內部結構參數對混合、傳質、傳光的影響分析結構,為平板生物反應器的設計及優(yōu)化提供新思路和方向。
[Abstract]:Microalgae have great potential application value in the fields of biological energy, environmental protection, food, health care products and medicine. However, the poor performance of microalgae has been restricting the development of microalgae. The optimization design and enlargement of the traditional photo bioreactor have long period and high cost, and can not fully study the internal reaction inside the reactor. In recent years, the study of microalgae culture photo bioreactor using computational fluid dynamics (CFD) has many advantages to make up the traditional methods, but there are still a lot of blanks due to the rising of the traditional method. In this paper, a multilevel intake multi section baffle reaction is proposed on the basis of the mainstream plate type bioreactor in the field of microalgae culture. The structure of the device is envisaged, and the CFD technology is used to study the mixing, mass transfer and transmission characteristics of the new type reactor. The specific results are as follows. First, the multi intake multi section baffle plate reactor calculation model is constructed with the ANSYS Fluent commercial software, and the Eulerian-Eulerian multiphase flow model and the PBM model are used for coupling. The simulation results compare with the experimental results to verify the feasibility and reliability of the simulation model established in this paper. The local gas holdup in the upper and middle section of the multistage inlet reactor is greatly influenced by the ventilation rate, and its lower performance parameters are less affected by the ventilation rate: its turbulent kinetic energy is in the lift. The distribution of the region is in Shuangfeng, and the turbulent kinetic energy distribution in the drop zone is relatively slow. Then, the flow flow and mass transfer characteristics of three kinds of reactors are compared by CFD simulation. The results show that the gas holdup, the mean velocity and turbulence of the multistage intake reactor at a certain ventilation rate are at a certain rate of ventilation. The performance evaluation parameters such as the mass transfer coefficient of liquid phase are greatly improved than those of the first two reactors. When the ventilation rate is 0.8 VVM, the gas holdup in the reactor C is 52.63% and 39.11% higher than that of the reactor A, B respectively. When the ventilation rate is 0.4 VVM and 0.6 VVM, the kLa value of the reactor C is increased by 36.16% and 11.27%., respectively than the counter reactor B, and the multiphase flow is used. The coupling method of the model and PBM model is used to further study the bubble characteristics that affect the mass transfer performance of the new reactor. The bubble diameter distribution and other bubble characteristic parameters show that the Bin-0 body integral of the reactor C is 32.79% lower than that of the reactor B at the reactor height of 390: the reactor B is more than 6 within the reactor B. The total volume fraction of the MM bubble diameter is 8.58%, and the C of the reactor is 0.54%.. The result shows that the reactor C can effectively reduce the bubble aggregation and the bubble distribution is good. This will be beneficial to the mass transfer. The light transmission characteristics of the three reactors are compared and analyzed in this paper. The results show that the reaction is a reaction. The results show that the reaction is a reaction. The radial mixing intensity in the light direction in the reactor is increased by the device C than the reactor B, the radial velocity of the reactor C is increased by 28.25% compared with the reactor B in the light region. The time of the average stay in the light region is shortened, and the period of the light dark cycle is also shorter than the B of the reactor B, and the light dark circulation frequency of microalgae in the light and dark areas of the reactor is accelerated. At last, the internal structure parameters (Ar/Ad) of the reactor C (Ar/Ad), the distance from the liquid surface (H0) and the length of the gap between the separators (D) were optimized through the simulation of the internal structure parameters of the reactor. The results showed that the mass transfer coefficient of the liquid phase and the radial velocity of the light region increased with the Ar/Ad value. The overall mixing situation is better when Ar/Ad is 0.5. The overall mixing performance and the radial velocity of the light region increase with the increase of H0. When the ho is 40 mm, the mass transfer performance is better. With the gap gap increasing, the radial velocity of ATK and the light region increases gradually, while the mass transfer performance of the reactor is 15mm when the gap gap is 15mm. To sum up, the reactor C is better than the other two kinds of reactors in mixing, transmission and mass transfer performance is greatly improved, reducing the coalescence of bubbles in the reactor, optimizing the bubble distribution and improving the flash effect. The structure parameters of the reactor internal structure are analyzed for the influence of mixing, mass transfer and transmission, and the design of the plate bioreactor and the design of the reactor. The optimization provides new ideas and directions.

【學位授予單位】：中國海洋大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：Q949.2

【參考文獻】

相關期刊論文 前10條

1 陶藝;袁壽其;張金鳳;張帆;陶建平;;渣漿泵葉輪磨損的數值模擬及試驗[J];農業(yè)工程學報;2014年21期

2 郭欣;孫德宇;李建隆;黃青山;;平板氣升環(huán)流式光生物反應器中氣泡特性的圖像法分析[J];計算機與應用化學;2014年06期

3 黃建科;康少鋒;李元廣;李偉;;蛋白核小球藻的光衰減模型及藻細胞受光特性參數的模擬[J];過程工程學報;2014年02期

4 劉建國;龍元薷;黃園;龐通;林偉;李凌;;微藻生物柴油研究現(xiàn)狀與發(fā)展策略[J];海洋科學;2013年10期

5 韓佳偉;趙春江;楊信廷;錢建平;邢斌;范蓓蕾;;基于CFD數值模擬的冷藏車節(jié)能組合方式比較[J];農業(yè)工程學報;2013年19期

6 程軍;莊良;黃云;孫晶;周俊虎;岑可法;;平板式微藻光反應器的流場優(yōu)化及閃光效應[J];浙江大學學報(工學版);2013年11期

7 李紹果;薛天艷;齊濤;劉長厚;;分段進氣多級環(huán)流反應器流動與傳質特性研究[J];化學工程;2013年07期

8 王琴;符笳茵;應月;黎奇欣;黃嘉玲;;廢水養(yǎng)殖高油微藻的研究進展[J];現(xiàn)代食品科技;2013年06期

9 王冬琴;譚瑜;盧虹玉;蘇偉明;胡雪瓊;李雁群;;微藻生物活性物質在食品工業(yè)中的應用進展[J];現(xiàn)代食品科技;2013年05期

10 岳麗宏;郝欣欣;;平板式光生物反應器內有效光分布研究[J];青島理工大學學報;2012年05期

，

本文編號：1892491