Slurry Bed Reactor Research Articles

Dealkylation of alkylphenols in phenol oil on acid zeolites

The majority of the phenolic compounds in coal tar are alkyl-substituted phenols. To overcome the difficulty of separation, zeolites catalyzed dealkylation of alkylphenols was studied in a slurry-bed reactor. ZSM-5 displayed higher catalytic performance than other zeolites within a group of acidic zeolites with various topologies (including SAPO-34, ZSM-23, MCM-22, USY, and Mordenite). The yield of phenol gradually increased together with the zeolite acidity, but the types and yields of byproducts also increased in step with it. The pore size of the zeolites was a significant influence at similar acidity. The micropore of ZSM-5 inhibited some bimolecular processes, decreasing disproportionation/transalkylation as a result of transition state shape selection. In this study, the reaction paths of alkylphenols were investigated, based on the composition of products catalyzed by different zeolites, the distribution of products under different conditions, and the reaction process of various alkylphenols. Reaction process of alkylphenols included dealkylation, isomerization, disproportionation, transalkylation, and C-C cracking. Dealkylation took the place of isomerization as the primary reaction when the reaction temperature exceeded 350 °C. Disproportionation, transalkylation, and C-C cracking were exacerbated by excessive temperature. In addition, excessive reaction time and pressure can exacerbate side reactions, alkylphenols yields and coke deposition.

Influence of the precursors in CuZnAl slurry catalyst preparation by the complete liquid phase for the ethanol synthesis from syngas

It has been found that CuZnAl slurry catalyst performance is influenced seriously by its precursors in ethanol synthesis from syngas. Herein, a series of the slurry catalysts were prepared by complete liquid phase method adopting different sol-gel and solution as components of precursors. Their catalytic performances were investigated in a slurry bed reactor and physicochemical properties were characterized by XRD, H2-TPR, NH3-TPD, N2 adsorption and XPS techniques. The results show that the catalyst Al–Zn(g)-Cu(s) prepared by adopting Zn gel and Cu solution as components of precursors exhibits the highest ethanol synthesis capacity, with the proportion of ethanol in the total alcohol reaching up to 45.36%. And no visible deactivation was detected over 168 h reaction. Characterization indicates larger Cu0 particles and a suitable range of surface Cu0/(Cu0+Cu+) ratios are favorable to the production of ethanol, the Cu0/(Cu0+Cu+) ratios can be adjusted partly by Cu0 particle sizes.

Research on Fluid Dynamics Behavior Monitoring System based on Slurry Bed Reactor

In this paper, a behavior monitoring system is developed based on the fluid mechanics in the slurry bed reactor. In using this system, the researchers studied the hydrodynamic behavior of the slurry bed, and this paper proposed the theoretical basis and hypothesis for monitoring the fluid dynamic behavior of the slurry bed. Therefore, this paper designs a fluid mechanics model that summarizes the fluid mechanics' behavior monitoring technology and analyzes the role of vertical tube bundles in the fluid mechanics' behavior monitoring of slurry beds. At the same time, this paper also discusses the problems faced by the fluid dynamics behavior monitoring system and the future development trend.

Catalytic Performance for CO Methanation over Ni/MCM-41 Catalyst in a Slurry-Bed Reactor

The Ni-based catalyst has been intensively studied for CO methanation. Here, MCM-41 is selected as support to prepare xNi/MCM-41 catalysts with various Ni contents and the catalytic performance for CO methanation in a slurry-bed reactor is investigated under different reaction conditions. The CO conversion gradually increases as the reaction temperature or pressure rises. As the Ni content increases, the specific surface area and pore volume of xNi/MCM-41 catalysts decrease, the crystallite sizes of metallic Ni increase, while the metal surface area and active Ni atom numbers firstly increase and then slightly decrease. The 20Ni/MCM-41 catalyst with the Ni content of 20 wt% exhibits the highest catalytic activity for CO methanation, and the initial CH4 yield rate is well correlated to the active metallic Ni atom numbers. The characterization of the spent xNi/MCM-41 catalysts shows that the agglomeration of Ni metal is accountable for the catalyst deactivation.

Alkylation of Isobutane with Butylenes over a Zeolite Catalyst in a Slurry Bed Reactor

Alkylation of Isobutane with Butylenes over a Zeolite Catalyst in a Slurry Bed Reactor

Fischer-Tropsch Synthesis on Co/SBA-15 Catalyst: Characterization and Oligomerization Modeling

In this study, we investigated the oligomerization mechanism of the Fischer-Tropsch synthesis catalyzed by a cobalt-based catalyst supported by SBA-15. The Co/SBA-15 catalyst contained 20% w/w of cobalt. It was prepared by the wet impregnation method and characterized by X-ray diffraction (XRD), N2 adsorption-desorption, temperature-programmed reduction (TPR), and scanning electron microscopy coupled to X-ray energy dispersion spectroscopy (SEM-EDS). The FT synthesis was conducted in a slurry bed reactor operating at 240–270°C, 2.0–3.0 MPa, and 1:1–2:1 H2:CO ratio (mol:mol). An oligomerization model, based on alkyl and alkenyl mechanisms for hydrocarbon chain propagation, was used for product distribution. Impregnation with cobalt and calcination did not alter the structure of SBA-15. Cobalt oxides, including Co2O3 and Co3O4, were the active phases of the reaction. Adding cobalt to the support lowered the specific surface area and the pore volume of the support but did not change the structure of SBA-15. Fischer-Tropsch synthesis and C5+ hydrocarbon selectivity increased at a low H2:CO ratio (1.0) and low temperatures (240–255°C). The content of branched-chain paraffin and olefins increased with a decrease in the H2:CO ratio and temperature. The parameters of the model were estimated, and the assumption of a dual mechanism was satisfied.

Selective Conversion of Syngas to Olefins via Novel Cu-Promoted Fe/RGO and Fe-Mn/RGO Fischer-Tropsch Catalysts: Fixed-Bed Reactor vs Slurry-Bed Reactor.

Fischer–Tropsch has become an indispensable choice in the gas-to-liquid conversion reactions to produce a wide range of petrochemicals using recently emerging biomass or other types of feedstock such as coal or natural gas. Herein we report the incorporation of novel Cu nanoparticles with two Fischer–Tropsch synthesis (FTS) catalytic systems, Fe/reduced graphene oxide (rGO) and Fe–Mn/rGO, to evaluate their FTS performance and olefin productivity in two types of reactors: slurry-bed reactor (SBR) and fixed-bed reactor (FBR). Four catalysts were compared and investigated, namely Fe, FeCu7, FeMn10Cu7, and FeMn16, which were highly dispersed over reduced graphene oxide nanosheets. The catalysts were first characterized by transmission electron microscopy (TEM), nitrogen physisorption, X-ray fluorescence (XRF), X-ray diffraction (XRD), and H-TPR techniques. In the SBR, Cu enhanced olefinity only when used alone in FeCu7 without Mn promotion. When used with Mn, the olefin yield was not changed, but light olefins decreased slightly at the expense of heavier olefins. In the FBR system, Cu as a reduction promoter improved the catalyst activity. It increased the olefin yield mainly due to increased activity, even if the CO2 decreased by the action of Cu promoters. The olefinity of the product was improved by Cu promotion but it did not exceed the landmark made by FeMn16 at 320 °C. The paraffinity was also enhanced by Cu promotion especially in the presence of Mn, indicating a strong synergistic effect. Cu was found to be better than Mn in enhancing the paraffin yield, while Mn is a better olefin yield enhancer. Finally, Cu promotion was found to enhance the selectivity towards light olefins C2–4. This study gives a deep insight into the effect of different highly dispersed FTS catalyst systems on the olefin hydrocarbon productivity and selectivity in two major types of FTS reactors.

Hydro-liquefaction of asphaltene catalyzed by molybdenum-nickel bimetallic catalysts in slurry bed

Abstract The aim of this study is to achieve the hydro-liquefaction of asphaltene for the production of liquid fuel. The oil soluble molybdenum catalysts, molybdenum dialkyl dithiophosphate, and nickel carboxylate precursor with different carbon chains, were synthesized. The catalysts were characterized by ICP-OES, TEM and XPS. Their catalytic performance for the hydro-liquefaction of asphaltene to liquid fuels was investigated in a slurry bed reactor by using decalin as hydrogen donor and dispersant. The results show that the bimetal catalytic system composed of molybdenum dialkyl dithiophosphate and caproic acid nickel produces more MoS2 and NiS x active species. The metal contents of which accounts for 81.8 and 81.0 wt% of the total amount of Mo and Ni, respectively, and thus exhibits the best catalytic performance among the catalysts studied. The liquid yield of the asphaltene hydrogenation over the bimetal catalyst is 84.6 wt%, which is much higher than that over other catalysts, and the coke content is only 8.6 wt% under the conditions of 1000 μg/g of total metal addition, 1:1 Mo/Ni metal mass ratio and 1:1 asphaltene/naphthalene mass ratio. The content of saturated and aromatic components in the liquid products of asphaltene hydrogenation of the bimetal catalyst system is 78.9 wt%, which is a high-quality liquid fuel component.

Investigation of alkaline complexant on ethanol synthesis from syngas over slurry CuZnAlOOH catalyst

A series of alkaline complexants promoted slurry CuZnAlOOH catalysts were prepared by a complete liquid-phase method. These catalysts were applied in a slurry bed reactor to selectively convert syngas into ethanol and higher alcohols (HAs). Herein, we showed that the addition of alkaline complexant remarkably enhanced both CO conversion and selectivity toward to ethanol and HAs in terms of ternary CuZnAlOOH catalyst. Besides, the formation of dimethyl ether (DME) was significantly suppressed. Interestingly, different from the traditional alkalis modified copper-based catalysts, these catalysts promoted by alkaline complexants mainly increased selectivity for ethanol, while not isobutanol. It also reduced the deactivation rate of the catalysts. These catalysts were comprehensively characterized by XRD, H2-TPR, NH3-TPD-MS, N2 adsorption, FT-IR, XPS and TEM techniques. It was found that the increase of ethanol selectivity was related to the decrease of catalyst surface acidity, while the decrease of surface Cu+/(Cu0+Cu+) was regarded to the main reason for the catalysts deactivation. This paper showed that the introduction of alkaline complexants into Cu-based catalysts exhibited the potentiality to improve the stability and the yield of ethanol in a slurry bed reactor.

Selective synthesis of epichlorohydrin via liquid-phase allyl chloride epoxidation over a modified Ti-MWW zeolite in a continuous slurry bed reactor

The epoxidation of allyl chloride (ALC) to epichlorohydrin (ECH) with H2O2 using a piperidine (PI)-modified Ti-MWW catalyst (Ti-MWW-PI) in a continuous slurry reactor was investigated to develop an efficient reaction system for the corresponding industrial process.

Solution-combusted nanosized Ni–Al2O3 catalyst for slurry CO methanation: effects of alkali/alkaline earth metal chlorides

Solution combustion synthesis (SCS) possesses many advantages for preparation of nanosized materials. In the process of SCS, a large amount of heat release results in the agglomeration of particles. Thus, the controllable synthesis of solution combustion is necessary. In this study, Ni–Al2O3 nanoparticles with various metal chlorides, i.e., LiCl, NaCl, KCl, MgCl2 and CaCl2, were prepared by SCS method and performed for CO methanation reaction in a slurry-bed reactor. All of the introduced metal chlorides could absorb reaction heat during the combustion process, among which the addition of NaCl minimizes the combustion temperature for its high heat capacity. Moreover, the molten NaCl exerts a steric hindrance effect that restrains the agglomeration of NiO particles, leading to the highest Ni dispersion and smallest Ni particles. MgCl2-added sample exhibits the lowest reducibility and Ni dispersion and the worst methanation activity. The performance shows that, under a harsh condition of 310 °C and 9200 mL (gcat h)−1, NaCl-added Ni–Al2O3 catalyst exhibits the optimal CO conversion, which keeps stable at ca. 87% in a 100-h test. This study offers a new strategy for nanosized catalyst preparation via SCS by introducing metal chlorides.

Complete Liquid‐Phase Preparation of CuFe‐Based Catalysts and Their Application in the Synthesis of Higher Alcohols from Syngas

AbstractCuFe‐based catalysts with different Cu/Fe molar ratios were prepared by the complete liquid‐phase method and applied in the synthesis of higher alcohols from syngas in a slurry bed reactor. The characterization results demonstrated that the CuFe‐based catalysts existed CuFe alloy and CuFe2O4. The molar ratio of Cu/Fe had an obvious effect on the synergistic interaction of CuFe bimetallic and its performance. The CuFe‐based catalyst with Cu/Fe molar ratio of 2 (Cu2Fe1) was the best catalyst, which showed better dispersibility and intimate contact between bimetal, and more spinel on the metal surface. The activity evaluation results exhibited that low temperature and low pressure were favorable for the formation of higher alcohols. The total alcohols selectivity was 46.87% and the higher alcohols mass fraction in total alcohols was 83.44% at 493 K and 3 MPa. This work may provide a novel method in preparing a highly efficient catalyst for higher alcohols synthesis from syngas under milder reaction conditions.

Direct production of olefins via syngas conversion over Co2C-based catalyst in slurry bed reactor.

Direct production of olefins via syngas conversion over a Co2C-based catalyst was investigated in a slurry bed reactor (SBR). It was found that the total selectivities to olefins and oxygenates reached 88.8C% at a CO conversion of 29.5% at 250 °C, 5 bar and H2/CO = 0.5. The hydrocarbon distribution greatly deviated from the classical Anderson–Schulz–Flory (ASF) distribution, with only 2.6C% methane selectivity was obtained. XRD and TEM characterization verified that the Co2C nanoprisms with special exposed facts of (101) and (020) constitutes the Fischer–Tropsch to olefins (FTO) active site. The catalytic activity increased gradually with rising the reaction temperature, while the product distribution almost kept unchanged under various reaction condition in SBR. Compared to the reaction in FBR, the Co2C-based catalyst exhibited relative better catalytic performance during FTO process in SBR. Specifically, a higher CO conversion, a lower methane selectivity and a higher total selectivities to olefins and oxygenates were achieved in SBR. In addition, the catalyst can be in situ reduced in slurry bed reactor at mild temperature (300 °C) and no obvious deactivation was found within nearly 100 h time-on-stream, which suggested a promising route for the direct production of olefins via syngas in industrial application.

Structure and surface characteristics of Fe-promoted Ni/Al2O3 catalysts for hydrogenation of 1,4-butynediol to 1,4-butenediol in a slurry-bed reactor

Nanostructured Ni–xFe/Al2O3 catalysts prepared by sol–gel combustion synthesis (SGC) display superior activity in hydrogenation of 1,4-butynediol to 1,4-butenediol. The Fe addition promoted the Ni reducibility and stabilized the Al2O3 structure.

Activity and selectivity of a cobalt-based Fischer-Tropsch catalyst operating at high conversion for once-through biomass-to-liquid operation

Abstract The effects of the harsh conditions achieved when operating the Fischer-Tropsch synthesis at high conversion on the activity and selectivity of Pt-Co/Al2O3 were studied in a slurry bed reactor at T = 220 °C, P = 20 bar, with a feed simulating synthesis gas generated by air-blown gasification (H2: CO: N2 = 4:2:6). The rate of CO consumption decreased with increasing conversion. Decreasing the space velocity and thus increasing the CO conversion was found to have slight effect on CO2 selectivity until a conversion of CO of 75%, after which a strong increase was observed. The production of CO2 raised the H2/CO ratio within the reactor resulting in a large increase in methane selectivity. An increase in CO conversion resulted in a decrease in chain growth probability and C5+ selectivity. The link between the change in the methane selectivity, chain growth probability and C5+ selectivity and the presence of carbonaceous species on the surface is explored.

Co/Ru/SBA-15 CATALYSTS SYNTHESIZED WITH RICE HUSK ASHES AS SILICA SOURCE APPLIED IN THE FISCHER-TROPSCH SYNTHESIS

Synthesis processes using simple compounds become attractive as they offer alternative routes for fuel production. Cobalt-based catalysts have wide applicability in the Fischer Tropsch process. This work aims to evaluate the catalyst Co/Ru/SBA-15 in the Fischer Tropsch synthesis. The catalyst was prepared with the molecular sieve SBA-15 synthesized using the hydrothermal method with rice husk ashes, treated by heat and chemical processes, as silica source; and incorporating, simultaneously, metals by wet impregnation of molar ratio 100Co/5Ru/139SiO2. The catalyst was submitted to heat treatment under nitrogen and synthetic air flow. The Fischer Tropsch synthesis was carried out in a slurry bed reactor operating at 240oC, 10 atm, and H2:CO molar ratio raging between 1 and 2. The SBA-15 and the catalyst were characterized by X-ray diffraction- XRD, X-ray energy dispersion- EDX, and nitrogen adsorption. The SBA-15 was characterized using scanning electron microscopy- SEM, and the catalyst was characterized by temperature programmed reduction - TPR and transmission electron microscopy - TEM. SBA-15 showed typical morphology traces of mesoporous materials with a small specific area of 627 m2/g. The catalyst presented the pre-defined composition, maintaining the structure, but with area reduction after impregnation (339 m2/g). The ranges of temperature reduction typical of iron oxides phases were found using RTP results. The catalyst showed high conversion to liquid hydrocarbons C5+ (88.20%) in the molar ratio H2/CO of 1:1.

Promotional Influence of Hydroxyl Complexing Agent on Ethanol Synthesis from Syngas Over CuZnAl Catalysts Without Other Metal Promoters

Ternary CuZnAl catalysts promoted with three kinds of hydroxyl complexing agents were prepared by a complete liquid-phase method and tested for ethanol synthesis from syngas in a slurry bed reactor. The catalysts were characterized by XRD, H2-TPR, NH3-TPD, N2 adsorption, XPS and TEM techniques. Activity results showed that ethanol selectivity enhanced significantly after the addition of hydroxyl complexing agents. Overall, the catalyst promoted by ethanolamine exhibited the best catalytic performance, with the concentration of ethanol and higher alcohols in the total alcohols reached up to 56.5% and 75.1%, respectively. The addition of hydroxyl complexing agents caused the reduction temperature of Cu+ shifted to be higher and the amount of weak acid sites to be decreased. It also favored the formation of AlOOH and Cu particles with larger particle size. These factors together contributed to the remarkable selectivity of ethanol and higher alcohols.

Sacrificial Carbon Strategy toward Enhancement of Slurry Methanation Activity and Stability over Ni-Zr/SiO2 Catalyst

Mesoporous silica-supported Ni-Zr catalysts prepared via the modified impregnation method by applying different solvents and calcination atmospheres were employed for CO methanation in a slurry-bed reactor. The results show that the glycerol-impregnated Ni-Zr/SiO2 catalyst exhibited higher specific surface area and Ni species dispersion and more intensive nickel–support interaction than the water-impregnated one and thus enhanced the catalytic activity and stability. Furthermore, the carbon could be constructed on the surface of the Ni-Zr/SiO2 catalyst from the carbonization of glycerol via calcination under an inert atmosphere and be removed through successive calcination in air. Owing to the improved nickel–support interaction, the carbon-sacrificed Ni-Zr/SiO2 catalyst exhibited higher Ni dispersion and smaller and more uniform Ni particle sizes, leading to catalytic activity for CO methanation that is higher than that of the catalysts without carbonization.

Investigation of copper precursors in the synthesis of higher alcohols from syngas over CuZnAl catalysts without promoters

The catalytic performances of different CuZnAl catalysts prepared using copper nitrate, copper acetate and copper citrate for CO hydrogenation to higher alcohols (C2+OH) were studied in a slurry bed reactor. Among these catalysts, the Cu-N catalyst prepared using copper nitrate showed a relatively higher C2+OH selectivity and no obvious deactivation occurred during the lifetime test for 120 h. The influence of copper precursors on the performance of the CuZnAl catalysts was investigated by XRD, 27Al-MAS-NMR, N2 adsorption-desorption, H2-TPR, NH3-TPD, FT-IR and XPS techniques. The results indicated that the size of Cu0 particles, textural properties, the chemical state of Cu species, the amount of surface acid and chemical composition varied, which led to diverse catalytic activities toward C2+OH synthesis. It was concluded that Cu0, Cu+ and AlOOH were all necessary in ethanol and C2+OH synthesis when using the CuZnAl catalysts without promoters and the synergism of these species was beneficial to the formation of C2+OH. This work further demonstrated that alkalis and Fischer-Tropsch elements were not indispensable for C2+OH synthesis from syngas.

Influence of Si on the performance of higher alcohols synthesis from syngas over CuZnSiAl catalysts without alkalis or Fischer-Tropsch elements

A series of CuZnSiAl catalysts with Si/Al molar ratios from 0 to 1 were prepared by a complete liquid-phase method and tested for syngas to higher alcohols (C2+OH) in slurry bed reactor. The catalysts were characterized by XRD, H2-TPR, NH3-TPD, N2 adsorption, FT-IR and XPS techniques. Activity results showed that the mass fractions of C2+OH in the total alcohols reached approximately 40.8% over CuZnAl catalyst without promoters. With increased Si/Al ratio, the crystallite size of Cu0 first increased until Si/Al = 0.5 and then decreased, However, the total number of weak acid on catalysts surface increased continuously and the surface Cu content gradually decreased. In addition, compared with the acidic Si sol, the catalysts promoted by alkaline Si sol exhibited better performance in terms of both stability and selectivity to C2+OH. It was found that AlOOH functioned for CO dissociation and C2+OH synthesis simultaneously required relative larger Cu particles, more number of weak acid and higher Cu content on catalyst surface. The incorporation of a suitable amount of alkaline Si sol was beneficial for both the stability as well as C2+OH selectivity, and the best catalytic performance was obtained when the Si/Al atomic ratio was 0.5.