硫化型催化剂的活性相及其加氢脱硫活性

以常规金属无机盐及硫化剂为原料合成硫化物前体,在硫化物前体溶液中加入有机助剂配成浸渍液,浸渍氧化铝载体制成镍钼基直接硫化型加氢催化剂(简称硫化型催化剂);采用XPS、TEM和高压DSC等分析方法对催化剂进行分析和表征,初步探索了催化剂中活性相的形成过程,并考察了催化剂的加氢脱硫活性。实验结果表明,硫化过程中硫化型催化剂上金属先经+5价的过渡态,再逐步生成二硫化钼相;有机助剂的加入不仅改变了催化剂的硫化过程,促进了金属镍在二硫化钼表面的分布,形成高活性的Ni Mo S相,还使硫化时的放热峰弥散减小,可避免开工过程的床层飞温问题。硫化型催化剂表面上活性金属完全硫化,催化剂的加氢脱硫活性高。

硫化型催化剂NMS/γ-Al_2O_3的催化加氢性能研究

以过渡金属盐-四硫代钼含硫酸铵为钼源,采用等体积浸渍法制备了以Mo-Ni为主要活性组分的硫化型加氢精制催化剂NMS/γ-Al2O3。以高氮催化柴油为原料,在实验室100 m L高压加氢装置上考察了该催化剂的加氢反应性能,并与传统氧化型催化剂NMO/γ-Al2O3进行了对比。结果表明,在反应温度350℃、氢分压6.5 MPa、氢油体积比500、体积空速1.0 h-1的工艺条件下,NMS/γ-Al2O3对催化柴油的脱硫率为99.7%,脱氮率为96.3%,脱硫活性略高于NMO/γ-Al2O3,脱氮活性优势明显。NMS/γ-Al2O3表面Mo S2平均堆积层数和平均晶片长度分别为4.0层和3.6 nm,Ni-Mo-S相主要以Ⅱ型活性相存在,活性位密度较高,这可能是该催化剂加氢性能优异的主要原因。

X射线光电子能谱对预硫化型催化剂活化过程的分析研究

在优选的离子枪刻蚀条件下,采用X射线光电子能谱深度剖析技术对不同活化时间的预硫化型催化剂进行深度剖析,分析不同活化时间对催化剂表面活化程度的影响。结果表明,预硫化型催化剂活化过程中伴随着表面氧化,且随着活化时间的延长,表面氧化程度加深;预硫化型催化剂活化3 h以后,表面基本硫化完全,随着活化时间的延长,硫化过程逐渐从表面向内部深入,同时表面氧化程度加深。

预硫化型CoMo加氢脱硫催化剂性能

采用等体积浸渍方法制备CoMo催化剂,选用不同预硫化方法制备一系列硫化型CoMo催化剂,考察反应温度和空速对加氢脱硫性能的影响,并与对比剂进行比较。结果表明,硫化型CoMo催化剂在不同温度和空速下,具有较好活性,在200 h周期实验中,硫化型CoMo催化剂表现出良好的稳定性,脱硫率98.7%。TEM表征显示,硫化型CoMo催化剂具有更多的MoS_2堆垛层,形成更多高活性Co-Mo-SⅡ型活性相。

清洁型KC-103S预硫化耐硫变换催化剂在GE水煤浆加压气化合成氨装置上的应用

从工艺流程、催化剂装填、升温导气和生产运行等方面介绍清洁型KC-103S预硫化耐硫变换催化剂国内首次工业应用情况。根据奎屯锦疆化工有限公司年产40万吨合成氨、70万吨尿素装置上运行结果表明:该催化剂性能优越,具有较高的强度及稳定性,活性稳定性好,抗毒物能力强,预硫化耐硫变换催化剂的应用能节省大量的开车时间及开车费用,是耐硫变换催化剂行业的一次突破性变革。

KC-103S型预硫化变换催化剂应用小结

蒲城清洁能源化工有限责任公司一期1 800 kt/a甲醇、700 kt/a聚烯烃项目2014年10月底一次性投料开车成功并试运行,运行初期变换系统采用常规氧化态(钴钼系)变换催化剂,开车前需进行氧化态催化剂的硫化,硫化时间较长,硫化过程中工艺气需放空,不仅开车成本较高,而且存在事故隐患和环境风险;为节约成本、缩短开车时间,2016年尝试采用昌邑凯特新材料有限公司生产的KC-103S型预硫化耐硫变换催化剂。简介变换催化剂的类型和蒲城能化变换系统的工艺流程,详细介绍KC-103S型预硫化耐硫变换催化剂的应用情况,并就开车情况、运行情况、催化剂使用寿命等方面与常规氧化态变换催化剂进行了比较。应用情况表明,预硫化耐硫变换催化剂不需要开车前的硫化,导气时间短,导气后系统可快速实现高负荷运行,节约了开车成本,可提早产出产品,增产效益明显,且因省去了硫化过程,避免了污染物的产生,环保效益和安全效益也非常显著。

硫化态三组元NiMoP/γ-Al_2O_3催化剂的TPR表征及噻吩HDS活性的研究

A series of sulfided tertiary NiMoP/ γ Al 2O 3 catalysts with different contents of MoO 3 were prepared by using molybdophosphoric acid of Keggin structure(H 3PMo 12 O 40 ) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo 0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 K and attributed to the hydrogenation of the so called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mo x+ sites on the MoS 2 phase(MoS 2 slab). With the introduction of nickel into the active phase of the sulfided Mo 0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/ γ Al 2O 3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of [ n (Ni)+ n (Mo)]/ n (Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni Mo S slab due to the loss of S during TPR process and vacancies or sites related to the H 2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.

KC-103S型预硫化耐硫变换催化剂在轴径向炉的装填和升温导气

KC-103S型预硫化耐硫变换催化剂用于中煤陕西榆林能源化工有限公司180万t/a甲醇生产中,总结了其在甲醇装置轴径向炉的装填、升温导气及性能。综合应用情况表明,该预硫化耐硫变换催化剂综合性能优异,装填便捷,可有氧装填,使用前无需硫化,缩短开车时间,更加安全、环保。

FCC汽油选择性加氢硫转移催化剂的实验研究

制备了以γ-Al2O3为载体的Ni基选择性加氢硫转移催化剂Mo-Ni/γ-Al2O3,并用于催化裂化(FCC)汽油的加氢硫转移反应。对比了预硫化型和氧化型Mo-Ni/γ-Al2O3催化剂的活性和选择性,并考察了无氧焙烧温度、活性组分负载量对预硫化型Mo-Ni/γ-Al2O3催化剂加氢硫转移催化性能的影响。采用模型化合物研究了硫醇在MoNi/γ-Al2O3催化下的反应,考察了烯烃和硫醇对硫转移反应的影响。结果表明,无氧焙烧温度400℃下制备得到的w(NiO)=8.2%、w(MoS2)=5.6%的预硫化型Mo-Ni/γ-Al2O3催化剂具有相对较高的加氢硫转移反应催化活性和选择性;硫醇与烯烃的反应在催化剂表面的加氢活性位上进行,硫醇先加氢脱硫,生成吸附态H2S,吸附态H2S再与吸附的烯烃反应生成大分子硫醇或硫醚,达到硫转移的目的。

麻疯树油加氢脱氧制备第二代生物柴油

采用硫化型NiMo/活性白土为催化剂,以非粮植物油麻疯树油为原料制备第二代生物柴油.利用等体积浸渍和CS_(2)原位活化结合的方法制备出硫化型NiMo/活性白土催化剂,并通过XRD、BET、Py-FTIR和NH_(3)-TPD等技术对其结构和性能进行表征.考察了不同反应温度、催化剂用量、反应初始氢压、反应时间下麻疯树油的转化率及生成C_(15)-C_(18)烃类的选择性.实验结果表明,最优的反应条件为:反应温度300℃、催化剂质量分数为7.5%、反应初始氢压3.5 MPa和反应时间60 min,在该反应条件下,麻疯树油的转化率达到95.19%,生成C_(15)-C_(18)烃类的选择性为84.53%.对最优油品的组分进行了分析,在硫化型NiMo/活性白土催化剂作用下,麻疯树油经加氢饱和、加氢脱氧、脱羰及裂化等反应生成含C_(15)-C_(18)链烃,即第二代生物柴油.

Hydrodeoxygenation of Phenolic Model Compounds over MoS2 Catalysts with Different Structures

Several MoS2 catalysts of different structure, prepared by in situ decomposition of ammonium heptamolybdate （AHM） and molybdenum naphthenate （MoNaph）, and by MoS2 exfoliation （TDM）, were characterized by BET, X-ray diffraction （XRD）, Energy Dispersive X-ray （EDX） and transmission electron microscopy （TEM）. The analysis showed that MoS2 structure was dependant upon the preparation procedure. The activity of the catalysts was determined by measuring the hydrodeoxygenation （HDO） of phenol, 4-methylphenol and 4-methoxyphenol using a batch autoclave reactor operated at 2.8 MPa of hydrogen and temperatures ranging from 320-370℃. By comparing the conversion, the reactivity order of the catalysts was： AHM〉TDM-D〉MoNaph〉thermal〉MoS2 powder〉 TDM-W. Also, the effect of reaction temperature on the HDO conversion was explained in terms of equilibrium of reversible reaction kinetics. The main products of the HDO for phenolic compounds were identified by gas chromatography/mass spectrometry （GC/MS）. The results showed that the product distribution and the HDO selectivity were correlated with the reaction temperature. Two parallel reaction routes, direct hydrogenolysis and combined hydrogenation-hydrogenolysis, were confirmed by the analysis of the product distribution. High temperature favored hydrogenolysis over hydrogenation for HDO of phenol and 4-methoxyphenol, whereas for 4-methylphenol the reverse was true.

Preparation of Bi_2WO_6 Photocatalyst and Its Application in the Photocatalytic Oxidative Desulfurization

A type of visible light photocatalyst Bi2WO6 was prepared from Bi(NO3)3.5H2O and Na2WO4.2H2O by means of hydrothermal method and was characterized by UV-vis diffuse reflectance spectrometry and XRD.Oxidative desulfurization via photocatalysis was investigated using thiophene dissolved in octane as the model compound,with hydrogen peroxide used as the oxidant.The effects of hydrogen peroxide mass fraction,irradiation time,dosage of photocatalyst Bi2WO6 on the desulfurization efficiency were also investigated.Under suitable conditions,the desulfurization rate of model compound reached over 70%.

Application of sodium titanate nanotubes doped with vanadium(VNaTNT) as a heterogeneous catalyst for oxidation of sulfides at room temperature

A heterogeneous titanate nanotube （TNT） catalyst containing TiO2, Na, and V has been synthesized and used in the chemoselective oxidation of sulfides to the corresponding sulfoxides in the presence of 30%H2O2 in water. Some of the advantages of our method include excellent yields, heterogene‐ous conditions, simplicity, compatibility with a variety of functionalities, and ease of isolation of the products. Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption were used for structural and textural charac‐terization of the catalyst （VNaTNT）.

Oxidative Desulfurization of Model Sulfur Compound by Potassium Ferrate in the Presence of Phosphomolybdic Acid Catalyst

In this work, the removal of thiophene from simulated oil has been studied by using the adsorption, extraction and oxidation/adsorption methods, respectively. In the adsorptive desulfurization process, different commercial adsorbents were used to eliminate thiophene at ambient pressure and mild temperature, and the results showed that carbon powder had the best adsorption ability. In the extractive desulfurization process, the best desulfurization result was obtained when DMF is used. In the oxidative/adsorptive desulfurization procedure using synthesized potassium ferrate as the oxidant and phosphomolybdic acid solution as the catalyst, thiophene was oxidized and removed from hydrocarbons in combination with active carbon adsorption, and the residual sulfur content of simulated oil could be reduced to 15.3mg/L from the original level of 200mg/L, with the desulfurization rate reaching 92.3%.