本文選題：超重力 + 共沉淀�。� 參考：《北京化工大學(xué)》2010年碩士論文

【摘要】： 甲醇是是C1化學(xué)的基礎(chǔ)物質(zhì),它是精細(xì)化工重要的基礎(chǔ)原料,主要用于制造甲醛、醋酸、氯甲烷、甲氨、硫酸二甲脂等有機(jī)產(chǎn)品,也是農(nóng)藥、醫(yī)藥的重要原料之一。近年來,能源危機(jī)的頻繁爆發(fā),以及環(huán)境污染的加劇,使人們對于新型清潔能源的需求越來越迫切。甲醇因其自身清潔、無毒、無污染的特性,自上世紀(jì)60年代來,吸引了越來越多的目光。經(jīng)過深加工后,甲醇可以作為柴油、汽油的摻燒物質(zhì),其燃燒值高,可減少尾氣污染。在我國這樣一個能源消耗大國,開展新型甲醇合成催化劑的研究具有廣闊的應(yīng)用前景和深遠(yuǎn)的意義。 目前,工業(yè)上銅基催化劑一般采用共沉淀法制備,但是傳統(tǒng)共沉淀反應(yīng)在攪拌釜中進(jìn)行,由于受到設(shè)備結(jié)構(gòu)等因素的限制,為了達(dá)到微觀結(jié)構(gòu)的均勻混合,就必須以高能耗為代價,因此不利于工業(yè)生產(chǎn)。此外,由于產(chǎn)物不能及時移出反應(yīng)體系,使得反應(yīng)體系中的物質(zhì)生成速率不均,反應(yīng)時間相差較大,CuO／ZnO兩組分相互分散度不高。由此生成的催化劑顆粒粗細(xì)不等,活性組分分布不均。 超重力技術(shù)的出現(xiàn),能夠很好的解決以上問題。它能實現(xiàn)反應(yīng)物在反應(yīng)體系內(nèi)的瞬間微觀均勻混合,制備催化劑時,反應(yīng)成核區(qū)和晶體生長區(qū)是分開的,使晶體的生長區(qū)置于完全宏觀混合區(qū),制備出的催化劑組分分布均勻、粒度分布窄且晶型可控。它的出現(xiàn)為催化劑的制備提供了新的探索途徑。 本文首次采用超重力反應(yīng)技術(shù)制備銅基甲醇合成催化劑,并對其催化性能進(jìn)行了表征與評價。在實驗中,制備一系列不同Cu／Zn摩爾比的CuO／ZnO／Al2O3催化劑,并對催化劑制備過程中存在的各種影響因素進(jìn)行了研究,采用XRD、TG-DSC、IR、BET、N2吸附、SEM等表征方法對催化劑前軀體、氧化物的物相組成、粒徑、孔結(jié)構(gòu)、表面形貌等進(jìn)行了研究。結(jié)果表明,采用超重力共沉淀法所制備的CuO／ZnO／Al203催化劑與傳統(tǒng)共沉淀法制備的催化劑相比,粒度更細(xì)化,比表面積更大,Cu、Zn兩組分分散度更好。同時,采用CO+H2混合氣在5.0MPa下進(jìn)行甲醇合成活性測試。結(jié)果表明,超重力共沉淀法制備的催化劑在220℃-260℃的范圍內(nèi)均具有很高的活性。其中以摩爾比為n(Cu)／n(Zn)／n(Al)=4.5／4.5／1的催化劑活性最高,CO轉(zhuǎn)化率達(dá)到35.3%。采用超重力共沉淀技術(shù)制備的催化劑,整體性能均優(yōu)于傳統(tǒng)共沉淀法,具有較好的工業(yè)應(yīng)用前景。
[Abstract]:Methanol is the basic material of C1 chemistry. It is an important basic raw material of fine chemical industry. It is mainly used in the manufacture of organic products such as formaldehyde, acetic acid, chloromethane, methylamine, dimethyl sulfate and so on. It is also one of the important raw materials of pesticide and medicine. In recent years, with the frequent outbreak of energy crisis and the aggravation of environmental pollution, the demand for new clean energy is becoming more and more urgent. Methanol has attracted more and more attention since 1960s because of its clean, nontoxic and pollution-free characteristics. After deep processing, methanol can be used as a mixture of diesel oil and gasoline, its combustion value is high, and the tail gas pollution can be reduced. In a large energy consuming country such as China, the research of new methanol synthesis catalyst has broad application prospect and far-reaching significance. At present, coprecipitation method is generally used for coprecipitation of coprecipitation catalysts in industry, but the traditional coprecipitation reaction takes place in agitator. Due to the limitation of equipment structure and other factors, in order to achieve homogeneous mixing of microstructure, It must be at the expense of high energy consumption, so it is not conducive to industrial production. In addition, because the product can not be moved out of the reaction system in time, the formation rate of substances in the reaction system is uneven, and the reaction time is quite different. The dispersion of the two components is not high. The resulting catalyst has different particle sizes and uneven distribution of active components. The emergence of high-gravity technology, can solve the above problem very well. It can realize the instantaneous microscopic homogeneous mixing of reactants in the reaction system. When the catalyst is prepared, the nucleation region and the crystal growth region are separated, so that the crystal growth region is placed in the complete macroscopic mixing region, and the composition of the prepared catalyst is uniformly distributed. The grain size distribution is narrow and the crystal form is controllable. It provides a new approach for the preparation of catalysts. In this paper, the copper-based methanol synthesis catalyst was prepared by high gravity reaction for the first time, and its catalytic performance was characterized and evaluated. In the experiment, a series of CuO/ZnO/Al2O3 catalysts with different molar ratio of Cu/Zn were prepared, and the influencing factors during the preparation of the catalyst were studied. The phase composition of the precursor and oxide of the catalyst was characterized by XRDX TG-DSCIRN / BETN 2 adsorption method. The particle size, pore structure and surface morphology were studied. The results show that the CuO/ZnO/Al203 catalyst prepared by hypergravity coprecipitation method has smaller particle size and higher specific surface area than that prepared by conventional coprecipitation method, and the dispersion of the two components is better than that prepared by conventional coprecipitation method. At the same time, the activity of methanol synthesis was tested by CO H 2 mixture under 5.0MPa. The results show that the catalysts prepared by hypergravity coprecipitation have high activity in the range of 220 鈩，

本文編號：1908377