非晶态催化剂催化生物油含氧化合物加氢脱氧
发布时间：2018-08-20 17:45
【摘要】：随着石油资源的不断枯竭及环境污染的日趋加剧,生物油作为新型环保的可再生能源受到各国的重点关注。然而,由生物质裂解而得到的生物油因含有大量含氧化合物,包括醇类、酮类、酸类和酚类等,氧含量高达50%以上,导致生物油的热值低、储存和热稳定性差、腐蚀性强,阻碍了其广泛应用,因此可以通过对生物油进行催化加氢脱氧,改善其品质。采用非晶态雷尼镍催化剂,在高压反应釜内对二丙酮醇、糠醛、苯酚和愈创木酚等生物油含氧化合物进行低温催化加氢实验,研究和推测了模型化合物催化加氢特性及反应机理。实验结果表明:温度是影响催化加氢活性的最主要因素,温度过高容易导致催化剂晶化而降低催化活性;在反应温度180℃、压力3 MPa、反应时间4 h以及催化剂量8wt.%时,模型化合物的转化率和饱和醇的选择性分别达到100.00%和97.74%以上;在此反应条件催化真实生物油的体系中,饱和醇的收率达到44.00%,pH从4.08升至5.13;通过对模型反应机理的探讨,得出模型主要通过两种加氢方式进行:即不同化合物分别以其O上的孤对电子选择性地与催化剂上的两种活泼态H(弱吸附的Ni-H、游离的原子态氢)进行加氢反应,完成催化加氢过程。通过化学还原法制备了以KBH4为还原剂的Ni-B催化剂,考察了添加助剂Co和载体γ-Al2O3对制备Ni-B催化剂及其催化性能的影响,并采用X射线衍射仪(XRD)、比表面积(BET)和扫描电子显微镜(SEM)对催化剂的形貌进行表征。由表征结果分析可知:所制备的催化剂均为非晶态催化剂,催化剂的热稳定性顺序为Ni-Co-B/γ-Al2O3-20%Ni-Co-B-5/5Ni-B-3.5;与Ni-B-3.5和Ni-Co-B-8/2相比,Ni-Co-B/γ-Al2O3-20%催化剂的颗粒更加细微、分散更加均匀;负载γ-Al2O3之后的催化剂比表面积更大,有利于提高催化剂的活性。以糠醛、二丙酮醇和愈创木酚的催化加氢为探针反应考察了Ni-B系催化剂Ni/Co摩尔比、金属负载量等制备条件以及反应温度、压力、时间对催化剂性能的影响。使用Ni-Co-B-5/5为催化剂时,150℃、4MPa、反应4 h,糠醛和二丙酮醇的转化率分别为100.00%和98.45%,产物中戊醇和四氢呋喃的量分别为10.65%和14.91%,催化剂开始具有加氢脱氧效果;而使用Ni-Co-B/γ-Al2O3-20%时,反应温度210℃,压力4 MPa,反应时间4 h的情况下,糠醛、二丙酮醇和愈创木酚的转化率分别为100.00%、100.00%和76.82%,产物戊醇、四氢呋喃和环己烷的选择性分别为10.51%、20.12%和11.06%。
[Abstract]:With the continuous depletion of petroleum resources and the worsening of environmental pollution, bio-oil as a new type of renewable energy environment has been the focus of attention. However, the bio-oil obtained from biomass pyrolysis contains a large number of oxygen-containing compounds, including alcohols, ketones, acids and phenols, and the oxygen content is as high as 50%, which results in low calorific value, poor storage and thermal stability, and strong corrosion. Therefore, it can improve the quality of bio-oil by catalytic hydrogenation deoxidation. The hydrogenation of oxygen compounds in bio-oil such as diacetone alcohol furfural phenol and guaiacol was carried out in a autoclave with amorphous Raney nickel catalyst at low temperature. The catalytic hydrogenation characteristics and reaction mechanism of the model compounds were studied and speculated. The experimental results show that temperature is the most important factor affecting the catalytic hydrogenation activity, and too high temperature can lead to the crystallization of the catalyst and decrease the catalytic activity, and when the reaction temperature is 180 鈩，
本文编号：2194480
[Abstract]:With the continuous depletion of petroleum resources and the worsening of environmental pollution, bio-oil as a new type of renewable energy environment has been the focus of attention. However, the bio-oil obtained from biomass pyrolysis contains a large number of oxygen-containing compounds, including alcohols, ketones, acids and phenols, and the oxygen content is as high as 50%, which results in low calorific value, poor storage and thermal stability, and strong corrosion. Therefore, it can improve the quality of bio-oil by catalytic hydrogenation deoxidation. The hydrogenation of oxygen compounds in bio-oil such as diacetone alcohol furfural phenol and guaiacol was carried out in a autoclave with amorphous Raney nickel catalyst at low temperature. The catalytic hydrogenation characteristics and reaction mechanism of the model compounds were studied and speculated. The experimental results show that temperature is the most important factor affecting the catalytic hydrogenation activity, and too high temperature can lead to the crystallization of the catalyst and decrease the catalytic activity, and when the reaction temperature is 180 鈩，
本文编号：2194480
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