共查询到15条相似文献,搜索用时 62 毫秒
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载体酸性对镍金属催化剂芳烃加氢抗硫性能的影响 总被引:3,自引:0,他引:3
制备了不同酸性载体γ-Al2O3、HY、SiO2-Al2O3和Sep(海泡石)负载的镍催化剂,在压力1.0MPa、温度200 ℃和空速2.0 h-1条件下,用固定床连续流动微反装置对催化剂进行了抗硫性能评价。模型反应物为甲苯-噻吩的混合液,含750 μg·g-1噻吩硫,用吡啶吸附红外光谱法研究了催化剂的酸性;用CO原位吸附红外光谱法研究了活性金属Ni的电子性能。结果表明,随载体酸性的增强,Ni原子缺电子性增强,催化剂芳烃加氢活性增加,抗硫性能提高。催化剂的抗硫性能主要与载体表面的B酸有关,与L酸无关。 相似文献
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国产镍基催化剂用于棕榈油加氢制硬化油的实验结果与进口催化剂进行比较表明,其催化性能基本达到替代进口催化剂的水平;在此基础上,通过正交试验得出国产催化剂YM9002用于棕榈油加氢过程中的最佳工艺操作条件为反应压力2.5 MPa,反应时间60 min,催化剂用量为0.3%。 相似文献
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分别以ZrO2、SiO2与Al2O3为载体,采用等体积浸渍法制备了Ni质量分数为15%的催化剂,考察了其催化顺酐液相加氢性能,并利用BET、XRD、H2-TPR以及TPO-MS等表征手段对催化剂进行了详细表征。结果表明,随载体不同各催化剂的加氢活性及选择性存在较大差异,Ni/Al2O3催化剂的C=C键加氢活性最高,但其几乎没有C=O加氢活性,催化顺酐加氢主产物为丁二酸酐。Ni/ZrO2催化剂具有最高的C=O加氢活性,催化顺酐加氢主产物为γ-丁内酯,在反应温度为483 K,氢气压力为5 MPa的条件下反应8 h时,Ni/ZrO2催化剂的γ-丁内酯选择性达79.20%。催化剂的套用实验表明,Ni/ZrO2与Ni/SiO2催化剂具有高的使用稳定性,Ni/Al2O3催化剂则在套用过程中快速失活。顺酐加氢至γ-丁内酯的中间产物--丁二酸酐与催化剂间的相互作用是影响催化剂加氢选择性及使用稳定性的主要原因。 相似文献
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A series of fixed-bed nickel hydrogenation catalysts was tested in the dearomatization of hydrocarbon solvents. The mechanism of catalyst deactivation by aromatic sulfur compounds was studied in high-pressure micro-flow equipment by variation of the experimental conditions and the sulfur content of the feed. It is concluded that catalyst deactivation proceeds under mild but realistic conditions through formation of a surface sulfide which blocks the active surface. The rate of the disappearance of the active sites is a first-order process with rate constant 1.0 × 10−3 (ppm S)−1 h−1. Under more severe conditions, more sulfide layers are formed, but bulk Ni3S2 was not observed even after full deactivation of the catalysts. The poisoning of the active sites in the latter case is no longer a first-order process. Consequently, under the circumstances investigated, the sulfur resistance of nickel catalysts is determined by the nickel surface area per unit weight of catalyst. 相似文献
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Said Irandoust Jonas Edvardsson 《Journal of the American Oil Chemists' Society》1993,70(11):1149-1156
The influence of various poisoning compounds on the hydrogenation of fat is reviewed. Sulfur-containing compounds, present
in both vegetable and marine oils, create serious catalyst deactivation problems. In this paper, the poisoning efffect of
sulfur and its role on the reactant adsorption in different hydrogenation reactions are discussed. Several factors affecting
the sulfur resistance of the catalyst metal are summarized. Other inhibitors influencing the fat hydrogenation, such as phosphorus
compounds, free fatty acids, sodium soaps, chlorophyll, halogen compounds and products of lipid oxidation, are also considered. 相似文献
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催化裂化装置产生的C4馏分中含有微量丁二烯,在后续加工过程中为有害杂质,需要除去,采用选择性加氢脱除二烯烃是一种有效的方法。研究了一种非负载型非贵金属镍基催化剂的制备方法,采用XRD、TEM、FT-IR和TG-DTG-DTA等考察催化剂制备条件对晶相结构及形貌特征的影响,并在高压固定床反应装置上考察催化剂对C4馏分中丁二烯选择性加氢脱除的催化反应性能。结果表明,采用碱镍物质的量比为1.05和温度120 ℃条件下合成的镍催化剂前驱体,在90 ℃制备的催化剂性能最优。在氢压1.0 MPa、反应温度60 ℃、氢油体积比20和液时空速2.0 h-1条件下,制备的镍基选择性加氢催化剂能将C4馏分中低含量丁二烯烃完全脱除,具有良好的二烯烃选择性加氢活性。 相似文献
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The stereoselective hydrogenation of thymol was studied in liquid phase over several nickel catalysts, modified by coimpregnation of inorganic compounds containing chlorine. The total activity of all catalysts studied was decreased and was on the same order of magnitude, indicating that chlorine even after reduction remains on the surface and is responsible for the poisoning effects. Such blocking of accessible sites results in similar reaction rates for the catalysts studied. Selectivity and stereoselectivity to menthols and menthones changed significantly. The modifiers could influence the rate of keto-enol transformations, which is thought to be the key selectivity and stereoselectivity governing step. 相似文献
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采用二次浸渍法制备镍催化剂,通过改变工艺条件进行单因素试验,考察不同工艺条件对镍系苯加氢催化剂性能的影响。结果表明,在纯氢环境下,程序升温可以使催化剂充分活化,在反应压力(0.6~0.8) MPa、液苯空速(0.8~1.0) h-1、反应入口温度约140 ℃和氢与苯物质的量比为6.0~8.0的条件下,催化剂具有良好的性能。 相似文献