λ-Al_2O_3和活性炭(AC)负载Co-Mo催化剂的对比研究

以λ-Al2O3和活性炭(AC)为载体分别负载Co、Mo制备了粗苯加氢催化剂(CoO,MoO3质量分数分别为2%,8%),利用BET和XRD技术对2Co8Mo/λ-Al2O3和2Co8Mo/AC的物化性能进行表征,在固定床微型反应装置上对比考察了Co-Mo/AC在HDS中的活性。结果表明:活性组分在AC中孔内高度分散,2Co8Mo/AC在T=300℃、P=3.0 MPa、LHSV=2 h-1及氢油体积比为600时对噻吩硫脱除率达到99%以上。     

一种体相加氢脱硫催化剂的程序升温硫化表征

在全自动化学吸附仪上,用程序升温硫化（TPS）技术对一种体相加氢脱硫催化剂进行表征,考察了金属与载体的相互作用、金属间的相互作用以及焙烧温度对这种催化剂硫化性能的影响。结果表明,MoO3负载于Al2O3载体后,硫化峰温大幅降低,并在TPS谱图中体现出分步硫化的过程,证明MoO3与载体间存在相互作用,形成了易于硫化还原的活性中心。当Mo和Ni共同作用于载体时,形成了更易于硫化的Mo-Ni-O复合相。Co的加入加强了Mo与Ni间的协同作用,Co、Mo、Ni与Al形成了更易硫化的活性中心。W的加入反而改变了硫化中心的性质,使硫化温度提高。对（Mo＋Ni）/Al2O3和（Co＋Mo＋Ni）/Al2O3催化剂,于500℃焙烧时,催化剂硫化性能最好。最后得出结论：当Co、Mo、Ni 3种金属共同作用于载体,并于500℃焙烧时,其硫化中心活性最高。     

溶胶-凝胶法制备MoP/SiO_2催化剂及其加氢脱硫催化活性的研究

以正硅酸乙酯为硅源,以钼酸铵和磷酸二氢铵为钼源和磷源,采用溶胶-凝胶法,经干燥、焙烧处理后,程序升温还原制备得到二氧化硅负载磷化钼(MOP)催化剂,并以二苯并噻吩为模型化合物,对催化剂的加氢脱硫活性进行初步评价,考察了负载量、反应压力、反应温度等因素对催化活性的影响.结果表明,溶胶-凝胶法制备负载催化剂最佳磷化钼负载量为20%(质量分数);升高反应压力和温度均有利于提高二苯并噻吩的转化率,但降低了产物中联苯的含量.     

Changes in metal–sulfur bond energy in promoted and unpromoted molybdenum catalysts

Insight into the changes in the metal–sulfur bond energy in unpromoted and promoted (Co, Ni, or Fe) MoS₂ catalysts is obtained by temperature‐programmed reduction (TPR) studies of in situ sulfided catalysts. The experiments reveal a significant decrease in the metal–sulfur bond energy for the more active Co–Mo–S and Ni–Mo–S structures as compared to MoS₂. A similar decrease is not observed for the less active Fe–Mo–S structure. The sulfur coordination is directly measured by in situ EXAFS and the results support that one of the roles of the promoter atoms is to facilitate vacancy formation. The findings are in accord with recent density functional theory calculations. This revised version was published online in July 2006 with corrections to the Cover Date.     

一类混合动态系统(HDS)的时间最优路由调度*

本文研究服务过程为连续动态过程的单服务台型混合动态系统（ＨＤＳ）的时间最短路由调度问题。通过定义事件函数和估计服务时间，本文证明在一定条件下，可将此类动态调度问题化为静态调度问题加以求解。     

混合动态系统的稳定性

讨论混合动态系统（HDS）的稳定性问题。首先给出关于HDS的稳定性、可吸收性和渐近稳定性的几个结论,然后给出关于HDS的Lyapunov稳定性定量。     

利用HDS技术处理铜矿山废水的试验研究

本文介绍了德兴铜矿利用国际上先进的废水处理技术———HDS技术处理铜矿山废水的试验与研究。经过浆料再循环 ,摸索试验最佳参数 ,能够提高底渣浓度 ,消除废水处理的结钙现象。处理后的废水符合《国家废水初级排放标准》 ,为有色金属矿山处理酸性废水做出了积极而有效的探索     

从HDS废催化剂提钒残渣中回收镍的研究

研究了以HDS废催化剂提钒后的残渣为原料制备NiSO4·7H2O的工艺方法,实验结果表明,用浓度为3mol/L、摩尔比为3∶1的盐酸与硝酸混合酸在温度373K下浸取残渣3h,镍提取率可达90%以上。通过调节溶液pH值,可水解除去Al3+、Fe3+、Cu2+,通过加入NaF可除去Ca2+和Mg2+,制得的NiSO4·7H2O样品纯度可达到99%以上。     

Ultra-deep desulfurization of coker and straight-run gas oils: Effect of lowering feedstock 95% boiling point

Production of diesel fuels with ultra-low-sulfur levels by deep desulfurization of gas oil feeds has received considerable importance in the petroleum refineries in recent years. The type of the gas oil feed and its distillation temperature play a key role in the deep desulfurization process. In the present research project, the effect of lowering the 95% distillation temperature (T₉₅) of two gas oil feeds, namely, straight-run gas oil (SRGO) and coker gas oil (CGO), on deep desulfurization to ultra-low-sulfur levels was investigated. The results showed that for both types of feeds a higher degree of desulfurization was achieved with reduction of T₉₅ from > 360 °C to < 340 °C. The refractory alkyl dibenzothiophenes boiling above 320 °C were present in very low concentrations in the low-boiling cuts and deep HDS to ultra-low-sulfur levels (< 50 ppm) was achieved at low severity operating conditions. Among the two feeds, the CGO that contained high nitrogen content, high concentrations of sterically hindered alkyl DBTs and high aromatics content (low feed saturation) was more difficult to desulfurize than SRGO.     

The functionalities of Pt/γ-Al2O3 catalysts in simultaneous HDS and HDA reactions

A Pt/γ-Al₂O₃ catalyst was tested in simultaneous hydrodesulfurization (HDS) of dibenzothiophene and hydrodearomatization (HDA) of naphthalene reactions. Samples of it were subjected to different pretreatments: reduction, reduction–sulfidation, sulfidation with pure H₂S and non-activation. The reduced catalyst presented the best performance, even comparable to that of Co(Ni)Mo catalysts. All catalyst samples were selective to the HDS reaction over HDA, and to the direct desulfurization pathway of dibenzothiophene HDS over the hydrogenation reaction pathway of HDS. The effect of H₂S partial pressure on the functionalities of the reduced Pt/γ-Al₂O₃ catalyst was studied. The results showed that an increase in H₂S partial pressure does not cause poisoning, but an inhibition effect, without changing the catalyst selectivity. Accordingly, the activity trends were ascribed to adsorption differences between the different reactive molecules over the same catalytic active site. TPR characterization along with a thermodynamics analysis showed that the active phase of reduced Pt/γ-Al₂O₃ is constituted by Pt⁰ particles. However, presulfidation of the catalyst leads to a mixture of PtS and Pt⁰ which has a negative effect on the catalytic performance without changing catalyst functionalities.