本文選題：反應(yīng)結(jié)晶　切入點(diǎn)：環(huán)流結(jié)晶器　出處：《中國(guó)科學(xué)院大學(xué)(中國(guó)科學(xué)院過(guò)程工程研究所)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：氣升式內(nèi)環(huán)流反應(yīng)器混合性能好、傳熱傳質(zhì)效率高,被廣泛應(yīng)用在生物技術(shù)、廢水處理等領(lǐng)域。相對(duì)于攪拌結(jié)晶器,其內(nèi)部剪切力小、剪切場(chǎng)均勻且無(wú)機(jī)械傳動(dòng)部件,因此在結(jié)晶領(lǐng)域受到越來(lái)越多的關(guān)注。然而,對(duì)于環(huán)流反應(yīng)器中的反應(yīng)結(jié)晶過(guò)程,尚未有人對(duì)其進(jìn)行過(guò)研究。本文以氫氧化鎳沉淀反應(yīng)為模型反應(yīng),對(duì)環(huán)流反應(yīng)器中的反應(yīng)結(jié)晶過(guò)程進(jìn)行了研究。首先采用正交實(shí)驗(yàn),在氣升式內(nèi)環(huán)流結(jié)晶器中制得了類球形的氫氧化鎳顆粒,并與攪拌結(jié)晶器進(jìn)行對(duì)比實(shí)驗(yàn)。通過(guò)對(duì)兩類結(jié)晶器中所得顆粒進(jìn)行XRD、SEM、粒徑大小、振實(shí)密度、顯微鏡圖像等分析,完善了氫氧化鎳顆粒的生長(zhǎng)機(jī)制,即:溶液中析出的晶粒在流體中運(yùn)動(dòng)時(shí),隨機(jī)碰撞團(tuán)聚在一起,形成氫氧化鎳顆粒,這個(gè)聚并過(guò)程決定了顆粒的粒徑大小;新生成的顆粒中,晶粒間空隙較大,在適當(dāng)?shù)姆磻?yīng)條件下,組成顆粒的晶�？梢岳^續(xù)生長(zhǎng),填補(bǔ)晶粒間的空隙,使得顆粒密度上升。在此基礎(chǔ)上,依次探索了初始氨水添加量VN、pH、加料方式、導(dǎo)流筒長(zhǎng)度Hd和氣體流量qg等操作條件對(duì)氫氧化鎳顆粒內(nèi)晶粒生長(zhǎng)的影響規(guī)律,主要結(jié)果如下:(1)Ni(OH)2顆粒內(nèi)的晶粒大小D隨VN、pH及Hd的增加,均呈現(xiàn)先逐漸增大,而后逐漸降低的規(guī)律,當(dāng)VN=300 mL、pH=11.4和Hd=250 mm時(shí),所制備氫氧化鎳顆粒內(nèi)的晶粒最大、產(chǎn)品質(zhì)量最佳。(2)環(huán)流結(jié)晶器頂部氣液分離區(qū)的微觀混合最佳,當(dāng)加料位置選在此處時(shí),所制備氫氧化鎳顆粒內(nèi)的晶粒最大。(3)qg對(duì)環(huán)流結(jié)晶器內(nèi)所制備氫氧化鎳顆粒內(nèi)的晶粒大小影響顯著。隨著qg的增加,晶粒大小也逐漸變大。
[Abstract]:The air-lift inner loop reactor has good mixing performance and high heat and mass transfer efficiency. It is widely used in biotechnology, wastewater treatment and other fields. Compared with the stirring mould, the internal shear force is small, the shear field is uniform and there are no mechanical transmission parts. Therefore, more and more attention has been paid in the field of crystallization. However, the reaction crystallization process in the loop reactor has not been studied. In this paper, the nickel hydroxide precipitation reaction is used as a model reaction. The reaction crystallization process in a loop reactor was studied. Firstly, spherical nickel hydroxide particles were prepared in an air-lift inner loop mold by orthogonal experiment. The growth mechanism of nickel hydroxide particles was improved by the analysis of XRDX SEM, particle size, vibrational density, microscope image and so on. That is, when the precipitated grains in the solution move in the fluid, they are randomly collided and agglomerated together to form nickel hydroxide particles, which determines the size of the particles. Under the appropriate reaction conditions, the grains can continue to grow, fill the gap between the grains, and increase the density of the particles. On this basis, the initial amount of ammonia water added VN ~ (2 +) pH and the feeding method are explored in turn. The effect of operating conditions such as tube length and gas flow rate QG on the grain growth in nickel hydroxide particles is studied. The main results are as follows: the grain size D increases with the increase of VNN pH and H d, and the main results are as follows: (1) the grain size D increases at first with the increase of VNN pH and H d. However, when the pH value of VN=300 MLX was 11.4 and Hd=250 mm, the grain size of nickel hydroxide particles was the largest and the product quality was the best. The micromixing of gas-liquid separation zone at the top of the circulator was the best, and when the feeding position was selected here, The maximum grain size in nickel hydroxide particles. QG has a significant effect on the grain size of nickel hydroxide particles prepared in the loop crystallizer. With the increase of QG, the grain size of nickel hydroxide particles increases gradually.
【學(xué)位授予單位】：中國(guó)科學(xué)院大學(xué)(中國(guó)科學(xué)院過(guò)程工程研究所)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ138.13

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本文編號(hào)：1571915