Preparation,Structure Characterization and Hydrodesulfurization Performance of B-Ni2P/SBA-15/Cordierite Monolithic Catalysts

A series of B-Ni2P/SBA-15/cord monolithic catalysts were prepared by coating the slurry of the B-Ni2P/SBA-15 precursors on a pretreated cordierite support, and followed by temperature-programmed reduct...     

程序升温法制备WP催化剂及其催化性能

以偏钨酸铵和磷酸氢二铵为原料,采用程序升温还原法制备体相WP催化剂,用质量分数0. 8%二苯并噻吩(DBT)溶液为模型化合物,考察磷化钨(WP)催化剂的加氢脱硫反应性能。采用XRD对催化剂进行表征,制备的WP催化剂移入固定床反应器前用体积分数10%H2S-Ar混合气体钝化,保证其结构未被破坏。实验表明,程序升温还原法成功制备出WP催化剂。WP催化剂具有良好的加氢性能,在WP催化剂上,二苯并噻吩主要以直接脱硫路径为主。     

Trickle bed reactor diluted with fine particles and coiled tubular flow-type reactor for kinetic measurements without external effects

Gas and liquid velocities in laboratory scale trickle bed reactors are one or two orders of magnitude lower than those in commercial reactors. Then, the kinetic data may include the external effects. This shortcoming of laboratory scale trickle bed reactor can be resolved by diluting the catalyst bed with fine inert particles. The catalyst bed dilution increases dynamic liquid holdup, pressure drop, gas–liquid mass transfer coefficient. Hydrogenation of 2-phenylpropene on Pd/Al₂O₃ was performed with the trickle bed reactor diluted with fine inert particles and the coiled tubular flow-type reactor to compare the kinetics with that of the basket type batch reactor. The trickle bed reactor diluted with fine inert particles is suitable to obtain the reaction rate without external effects even if the liquid velocity is low. The coiled tubular flow-type reactor should be used at high gas velocities.     

La-Ni2P/SBA-15/堇青石整体式催化剂及加氢脱硫性能

以介孔分子筛SBA-15为载体,制备一系列不同La含量的La-Ni₂P/SBA-15催化剂前驱体,将La-Ni₂P/SBA-15前驱体涂覆在预处理的整体式载体堇青石上,在H2气氛程序升温还原,制备不同La含量的La-Ni2P/SBA-15/堇青石整体式催化剂。对合成的催化剂进行X射线衍射和N2吸附-脱附结构表征,并评价对二苯并噻吩的加氢脱硫活性。结果表明,Ni₂P存在于所有的La-Ni2P/SBA-15/堇青石整体式催化剂中,且随着La含量的增加,La-Ni2P/SBA-15/堇青石整体式催化剂的比表面积和孔体积均有一定程度的提高,催化活性也提高。对于Ni2P/SBA-15/堇青石整体式催化剂,在300 ℃和380 ℃时,二苯并噻吩加氢脱硫转化率仅为27.2%和91.3%;而1.5%La-Ni₂P/SBA-15/堇青石催化剂在300 ℃和380 ℃时,二苯并噻吩转化率分别为36.8%和96.3%,显示出较好的二苯并噻吩加氢脱硫活性。La-Ni₂P/SBA-15/堇青石整体式催化剂在对二苯并噻吩的加氢脱硫过程中,以直接脱硫和加氢脱硫两种脱硫方式同时进行,并且以直接脱硫为主。     

自产气气提与纤维床反应器耦合发酵生产丁醇

采用发酵产物中的二氧化碳（CO₂）和氢气（H₂）作为循环气提气源,对丙酮丁醇梭菌（Clostridium acetobutylicum CGMCC 5234）发酵产物进行原位气提,实现丙酮、丁醇和乙醇混合物（ABE）的连续纤维床固定化发酵生产。连续发酵实验进行了12批次共309 h,总溶剂ABE当量浓度为133.3 g·L^-1（其中丁醇 83.5 g·L^-1,丙酮38.4 g·L^-1,乙醇11.4 g·L^-1）,葡萄糖消耗率为1.29 g·（L·h） ^-1,总溶剂ABE产率为0.431 g·（L·h） ^-1,转化率为0.333 g·g^-1,其中丁醇产率为0.270 g·（L·h） ^-1,转化率为 0.209 g·g^-1,发酵液中丁醇浓度控制在8～12 g·L^-1,显著优于游离发酵的结果。气提提取之后冷凝的ABE溶液出现分层现象,其中丁醇相丁醇浓度高达603.7 g·L^-1,极大地减缓后续分离提纯的负担。结果表明,自产气循环气提与纤维床固定化耦合连续发酵生产ABE（特别是丁醇）的工艺具有可行性和竞争力。     

复合SiO_2-Al_2O_3载体制备及其在柴油深度加氢脱硫中的应用

采用不同方法制备系列复合SiO_2-Al_2O_3载体,以等体积浸渍法负载硝酸镍和钼酸铵溶液制得加氢脱硫催化剂。通过BET、XRD和NH3-TPD对载体进行表征,并以直馏柴油为原料,考察不同载体对催化剂加氢脱硫活性的影响。结果表明,以硅质量分数27%的Si-Al-2载体负载浸渍液制得的催化剂具有较高的加氢脱硫活性,346℃可以将柴油中的硫含量脱除至小于10μg·g-1,加氢脱硫活性较对比剂有很大提高。     

Upgrading Siberian (Russia) crude oil by hydrodesulfurization: Kinetic parameter estimation in a trickle-bed reactor

Hydrodesulfurization(HDS) of sour crude oil is an effective way to address the corrosion problems in refineries and is an economic way to process sour crude oil in an existing refinery built for sweet oil.Siberian crude oil transported through the Russia-China pipeline could be greatly sweetened and could be refined directly in local refinery designed for Daqing crude oil after the effective HDS treatment.In this study,the HDS of Siberian crude oil was carried out in a continuous flow isothermal trickle-bed reactor over Ni-Mo/γ-Al_2 O_3.The effects of temperature,pressure and LHSV were investigated in the ranges of 320-360℃,3-5 MPa and 0.5-2 h~(-1),keeping constant hydrogen to oil ratio at 600 L·L~(-1).The HDS conversion could be up to 92.89% at the temperature of 360℃, pressure of 5 MPa,and LHSV of 0.5 h~(-1), which is sufficient for local refineries(84%).A three phase heterogeneous model was established to analyze the performance of the trickle-bed reactor based on the two-film theory using Langmuir-Hinshelwood mechanism.The order of sulfur component is estimated as 1.28,and the order of hydrogen is 0.39.By simulating the reactor using the established model,the concentration of H_2, H_2 S and sulfur along the catalyst bed is discussed.The model is significantly useful for industrial application with respect to reactor analysis,optimization and reactor design,and can provide further insight of the HDS of Siberian crude oil.     

Effect of phase maldistribution on performance of two-phase catalytic monolith reactor and its comparison with trickle bed reactor

Monolith reactors are widely considered as an alternative to the conventional trickle bed reactor. For the commercial deployment of monolith reactors, comparative performance studies are required. Reliable comparative and performance studies require a detailed understanding of the effect of phase distribution/maldistribution on the performance studies. In this work, performance and comparative studies were carried out in a relatively large column that was 4.8 cm in diameter. Experiments were performed in the same conditions that were used in studies for which phase distribution data were available. Since the properties of the catalyst used were different in both the reactors, the apparent kinetics were studied to facilitate the comparison. The hydrogenation of alpha-methyl styrene (AMS) was used as a test reaction. From the performance studies, it was found that the effect of maldistribution on the performance was stronger than the catalyst availability. From the comparative studies, it was found that the monolith reactor with maldistributed flow conditions provides higher productivity than the trickle bed reactor.     

MIL-101固载磷钨酸催化氧气氧化脱硫性能

采用一步包覆法成功地将磷钨酸（HPW）固载到多金属有机骨架MIL-101中,将其作为催化剂,氧气（O₂）作为氧化剂,用于催化氧化模拟油品的脱硫实验。系统地研究了氧气流速、反应温度、硫含量对脱硫效率的影响,筛选出最佳反应条件,同时考察了空气作为氧化剂用于油品脱硫的可行性。结果表明,当初始硫含量为350 μg·g^-1,氧气流速为90 ml·min^-1,反应温度为75℃,催化剂用量占模拟油品质量的1%,反应时间60 min,二苯并噻吩（DBT）的转化率可达74%。此外,通过重复利用实验证明催化剂有良好的再生活性。     

PHF-101型催化剂在2.0Mt·a~(-1)柴油加氢装置的工业应用

介绍了PHF-101型柴油加氢精制催化剂在中国石油乌鲁木齐石化分公司2.0 Mt·a~(-1)柴油加氢装置的工业应用情况,结果表明,在反应器入口压力7.83 MPa、空速1.84 h~(-1)、平均温度358℃和氢油体积比476∶1条件下,加工硫含量1 835μg·g~(-1)的混合汽油和柴油原料,精制柴油硫含量4.8μg·g~(-1),十六烷值提高4.0个单位。PHF-101型催化剂加氢性能优良,运转稳定性良好,满足国Ⅳ和国Ⅴ柴油生产需求。     

Removal of refractory S-containing compounds from liquid fuels on novel bifunctional CoMo/HMS catalysts modified with Ti

This study shows that titanium incorporation into hexagonal mesoporous silica (HMS) material has a positive effect on the activity of supported CoMo catalysts in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4-ethyl,6-methyl-dibenzothiophene (4E6MDBT). All catalysts showed the highest activity in the HDS of DBT than in the HDS of 4E6MDBT. The low reactivity observed in the HDS of 4E6MDBT is caused by the steric hindrance of the two alkyl groups at positions 4 and 6. The HDS of DBT over Ti-free catalyst proceeds exclusively via the direct desulfurization (DDS) route whereas over Ti-containing catalysts proceed via DDS (main route) and hydrogenation (HYD) pathway. The catalyst with a Si/Ti = 40 (molar ratio) was the most active in the HDS of DBT. A further increase in the Ti-content led to a decrease in Brønsted acidity and the S_BET specific area of the catalysts, which implies a decrease in the bifunctional character of the catalysts. Raman spectroscopy demonstrated that Ti-incorporation into HMS material leads to a decrease in the degree of polymerization of Mo species, and this implies a better dispersion of MoS₂, in good agreement with the XPS measurements. Regarding the HDS-resistant 4E6MDBT, the HDS reaction over the Ti-free catalyst was found to proceed exclusively via the dealkylation (DA) route. After Ti-incorporation into HMS material, additional acid-catalyzed isomerization occurs. With respect to industrial sample, the catalyst with Si/Ti = 40 showed lower intrinsic activity as well as greater selectivity toward isomerization route products.     

Design of monolithic catalysts for multiphase reactions

Monolith reactors are emerging as an attractive alternative for gas-liquid-solid reactor applications. The use of monolithic catalysts in new reactors as well as in retrofit designs should be based on an optimal choice of monolith geometry and operating conditions.In this contribution, we illustrate through fundamental modeling of the transport-kinetic interactions in a monolith catalyst how such an optimal design may be evolved. We also highlight the potential benefits a monolith catalyst has as compared to a pellet-based trickle bed reactor.     

Performance of catalytic reactors for the hydrogenation of CO2 to hydrocarbons

Fluidized bed and slurry reactors were employed to increase the CO₂ conversion and desirable product selectivity in the direct hydrogenation of CO₂ to hydrocarbons over K-promoted iron catalysts, as it is beneficial for the removal of heat generated due to highly exothermic nature of the reaction. The iron catalysts (Fe-K/Al₂O₃ and Fe-Cu-Al-K) were characterized by BET surface area, CO₂ and H₂ chemisorption, temperature-programmed reduction (TPR), X-ray diffraction (XRD) and temperature-programmed hydrogenation (TPH). The results of TPR and TPH study clearly indicated that co-precipitated Fe-Cu-Al-K catalyst has much higher reducibility and catalytic activity of CO₂ hydrogenation at low temperature than Fe-K/Al₂O₃. The performance of fluidized bed or slurry reactors was superior to that of fixed bed reactor for the CO₂ hydrogenation over Fe-Cu-Al-K catalyst in terms of CO₂ conversion and hydrocarbon productivity. Moreover, light olefins and heavy hydrocarbons were selectively synthesized in fluidized bed and slurry reactors, respectively. The optimum operation conditions and the effects of operating variables on the CO₂ conversion and its product distribution in these catalytic reactors were also discussed.     

Development of new catalysts for deep hydrodesulfurization of gas oil

TiO₂–Al₂O₃ composite supports have been prepared by chemical vapor deposition (CVD) over γ-Al₂O₃ substrate, using TiCl₄ as the precursor. High dispersion of TiO₂ overlayer on the surface of Al₂O₃ has been obtained, and no cluster formation has been detected. The catalytic behavior of Mo supported on Al₂O₃, TiO₂ and TiO₂–Al₂O₃ composite has been investigated for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and methyl-substituted DBT derivatives. The conversion over the Mo catalysts supported on TiO₂–Al₂O₃ composite, in particular for the HDS of 4,6-dimethyldibenzothiophene (4,6-DMDBT) is much higher than that of conversion obtained over Mo catalyst supported on Al₂O₃. The ratio of the corresponding cyclohexylbenzenes/biphenyls is increased over Mo catalyst supported on TiO₂–Al₂O₃ composite support. This means that the reaction rate of prehydrogenation of an aromatic ring rather than the rate of hydrogenolysis of C–S bond cleavage is accelerated for the HDS of DBT derivatives. The Mo/TiO₂–Al₂O₃ catalyst leads to higher catalytic performance for deep HDS of gas oil.     

Mathematical simulations of the performance of trickle bed and slurry reactors for methanol synthesis

Three- and two-phase reactor models were developed to simulate the performance of trickle bed and slurry reactors for methanol synthesis. The combination of orthogonal collocation and quasi-linearization was used to solve the trickle bed reactor model incorporating resistance to interparticle and intraparticle diffusion and resistance to mass transfer between gas and liquid phases. Model parameters were estimated independently from either published correlations or literature data. The model predicts significant resistance to intraparticle diffusion on the performance of trickle bed reactors. However, comparisons between pilot size trickle bed and slurry reactors illustrate the superior performance of trickle bed reactors over the slurry reactors for methanol synthesis even with diffusion limitations.     

Syngas production from methane reforming with CO2/H2O and O2 over NiO–MgO solid solution catalyst in fluidized bed reactors

Catalyst performance of NiO–MgO solid solution catalysts for methane reforming with CO₂ and H₂O in the presence of oxygen using fluidized and fixed bed reactors under atmospheric and pressurized conditions was investigated. Especially, methane and CO₂ conversion in the fluidized bed reactor in methane reforming with CO₂ and O₂ was higher than those in the fixed bed reactor over Ni_0.15Mg_0.85O catalyst under 1.0 MPa. In contrast, conversion levels in the fluidized and fixed bed reactor were almost the same over MgO-supported Ni and Pt catalysts. It is suggested that the promoting effect of catalyst fluidization on the activity is related to the catalyst reducibility. On a catalyst with suitable reducibility, the oxidized and deactivated catalyst can be reduced with the produced syngas and the reforming activity regenerates in the fluidized bed reactor during the catalyst fluidization. In addition, the catalyst fluidization inhibited the carbon deposition.     

A role of molybdenum and shape selectivity of catalysts in simultaneous reactions of hydrocracking and hydrodesulfurization

The hydrocracking and hydrodesulfurization (HDS) of n-heptane containing 0.2 mole% dibenzothiophene (DBT) were performed simultaneously using NiPtMo catalysts supported on HZSM-5, LaY and γ-Al₂O₃ in a high pressure fixed bed reactor. Molybdenum played an important role in both hydrocracking and hydrodesulfurization (HDS). We found that the sulfur compound, dibenzothiophene (DBT). in the reactant was adsorbed on a molybdenum site and converted to hydrogen sulfide so that the active sites of the catalysts for hydrocracking were less poisoned by DBT and the conversion of n-heptane over molybdenum impregnated catalyst was higher than that over molybdenum-free catalyst. The crystal structures of the molybdenum supported on the zeolite and γ-Al₂O₃ were mainly MoO_2.5 (OH)_0.5[021] and MoO₃[210] respectively as shown by XRD analysis. The structure of MoO_2.5(OH)_0.5 was easily reduced to MoS₂[003] during the reaction. After the reaction of 100 hours over the catalyst supported on γ-Al₂O₃ the crystal structure of MoO₃[210] partially changed to MoO₃[300] and the structure of MoS₂[003] was not observed. Because of the reactant shape selectivity of zeolite, the acid and the metal sites in the intracrystalline of the catalysts supported on zeolites were less poisoned by DBT. Therefore, both hydrocracking and HDS using n-heptane containing 0.2 mole% of DBT were successfully demonstrated over the prepared catalysts.     

尾油循环的煤焦油加氢实验研究

利用小型固定床加氢实验装置,将煤焦油和其加氢后的尾油混合,在温度(360~420)℃、压力(13~15)MPa、氢油体积比(1 500~1 700)∶1和液体体积空速0.25 h-1条件下进行加氢处理,所得产品切割得到的汽油馏分、柴油馏分和尾油馏分,分别占产物质量的16.12%、78.83%和5.05%,且产品中硫、氮含量很低,汽油中硫含量16.7μg·g~(-1),氮含量36μg·g~(-1),柴油中硫含量102.6μg·g~(-1),氮含量97μg·g~(-1),可用作清洁燃料。结果表明,尾油循环在煤焦油加氢过程中对煤焦油具有稀释作用,不仅减轻了设备负荷,同时也可以提高汽油和柴油收率。因此,以煤焦油加氢尾油循环加氢是一种高效、绿色环保制备燃料油的方法。     

A series of NiMo/Al2O3 catalysts containing boron and phosphorus: Part II. Hydrodenitrogenation and hydrodesulfurization using heavy gas oil derived from Athabasca bitumen

The hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) activity of a series of NiMo/Al₂O₃ catalyst containing boron (B) and phosphorus (P) were tested in a trickle bed reactor using heavy gas oil derived from Athabasca bitumen. Detailed characterization of these catalysts is given in Part I of this paper. Addition of B and P caused the formation of extremely strong acid sites on the catalyst and enhanced its HDN activity. The total (TN), basic (BN) and non-basic nitrogen (NBN) conversions increased from 61.9 to 78.0 wt.%, from 78.9 to 93.0 wt.% and from 52.8 to 70.0 wt.%, respectively, with the increase in B concentration from 0 to 1.7 wt.% to NiMo/Al₂O₃ catalyst. Similarly, TN, BN and NBN conversions increased from 61.9 to 78.4 wt.%, from 78.9 to 91.0 wt.%, and from 52.8 to 71.6 wt.% with the addition of 2.7 wt.% P. Though the addition of B and P to NiMo/Al₂O₃ catalyst did not show any significant effect on S conversion, the HDN and HDS activities of the catalyst containing 1.7 wt.% B and the one containing 2.7 wt.% P are comparable to those of a commercial catalyst. The activity over extended period indicated that catalysts L and K were more stable (lower deactivation rate) in terms of nitrogen removal activity than catalyst B (reference catalyst). On the other hand, the stability for sulfur removal was comparable with catalyst B. Selected catalysts after use were characterized using BET surface area, TPR, TPD and SEM techniques which were correlated further with their activities.     

Hydrodesulfurization of hindered dibenzothiophenes on bifunctional NiMo catalysts supported on zeolite–alumina composites

A series of NiMo catalysts supported on HNaY(x)–Al₂O₃ composites with different amounts of HNaY zeolite (x = 0, 5, 10, 20 and 100 wt.% of HNaY) was prepared and tested in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyl-DBT (4,6-DMDBT). The catalysts were characterized by N₂ physisorption, X-ray diffraction (XRD), FT-IR spectroscopy of pyridine and nitrogen oxide adsorption (Py and NO-FT-IR), temperature-programmed reduction (TPR), scanning electron microscopy (SEM-EDX) and high-resolution transmission electron microscopy (HRTEM). It was found that the increase in the zeolite content causes changes in the acidic properties of the catalyst (number of acid sites) as well as in the characteristics of the deposited metallic species (location and dispersion). Different activity trends with the amount of the zeolite were found for the DBT and 4,6-DMDBT hydrodesulfurization on NiMo/HNaY-Al₂O₃ catalysts. As for the HDS of DBT the alumina-supported catalyst presents the highest activity. The incorporation of the zeolite causes an initial drop and then the recovery of activity with zeolite content. In contrast, for the 4,6-DMDBT the HDS activity always increases with zeolite content. These two different catalytic behaviors seem to be due to two opposite effects, which affect the contribution of the reaction routes available for the HDS of each reactant, these effects are: (i) the decrease of MoS₂ dispersion caused by the incorporation of zeolite to the catalyst and (ii) the increase of the proportion of Brönsted acid sites with zeolite content. The reaction product distribution indicates that both types of sites, coordinatively unsaturated sites (CUS) of the MoS₂ and zeolite Brönsted acid sites, participate in the 4,6-DMDBT and DBT transformations.