scholarly journals Catalytic Steam Reforming of Toluene: Understanding the Influence of the Main Reaction Parameters over a Reference Catalyst

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 813 ◽  
Author(s):  
Hua Lun Zhu ◽  
Laura Pastor-Pérez ◽  
Marcos Millan
Keyword(s):  
Steam Reforming ◽  
High Performance ◽  
Space Velocity ◽  
Catalytic Performance ◽  
H2 Production ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Main Reaction ◽  
Toluene Conversion ◽  
Steam Reforming Of Toluene

Identifying the suitable reaction conditions is key to achieve high performance and economic efficiency in any catalytic process. In this study, the catalytic performance of a Ni/Al2O3 catalyst, a benchmark system—was investigated in steam reforming of toluene as a biomass gasification tar model compound to explore the effect of reforming temperature, steam to carbon (S/C) ratio and residence time on toluene conversion and gas products. An S/C molar ratio range from one to three and temperature range from 700 to 900 °C was selected according to thermodynamic equilibrium calculations, and gas hourly space velocity (GHSV) was varied from 30,600 to 122,400 h−1 based on previous work. The results suggest that 800 °C, GHSV 61,200 h−1 and S/C ratio 3 provide favourable operating conditions for steam reforming of toluene in order to get high toluene conversion and hydrogen productivity, achieving a toluene to gas conversion of 94% and H2 production of 13 mol/mol toluene.

Influence of Parameters on Catalytic Performance over Different Modified ZSM-5 Zeolite for the IMTO Process

2013 ◽  
Vol 648 ◽  
pp. 143-146
Author(s):  
Fei Liu ◽  
Ting Li ◽  
Peng Long Ye ◽  
Jian Xin Cao ◽  
Duan Hua Guo
Keyword(s):  
Raw Materials ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Operating Conditions ◽  
Light Olefins ◽  
Molar Ratio ◽  
Process Conditions ◽  
Alternative Route ◽  
Methanol To Olefin ◽  
Low Rate

The methanol to olefin with iodide method (IMTO) is a potential and alternative route for its mild process conditions, which produces methyl iodide as intermediate. Methanol can be highly converted, yielding high rates of selectivity to light olefins, by its reaction over varies modified ZSM-5 zeolites. Efforts have been taken to optimize the reaction with respect to selectivity of olefin and conversion of methanol. Based on the analysis of gas chromatography, the following operating conditions were obtained: 250 °C of reaction temperature, CH3OH:HI:H2O=1:1:3 of the molar ratio of raw materials, 2.5 h-1 of methanol space velocity and 30 ml•min-1 of nitrogen low rate.

scholarly journals Effect of Operating Conditions on the Performance of Rh/TiO2 Catalyst for the Reaction of LPG Steam Reforming

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 374
Author(s):  
Aliki Kokka ◽  
Theodora Ramantani ◽  
Paraskevi Panagiotopoulou
Keyword(s):  
Reaction Temperature ◽  
Steam Reforming ◽  
Catalyst Deactivation ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Operating Conditions ◽  
Propane Conversion ◽  
Liquefied Petroleum Gas ◽  
Steam Content ◽  
Tio2 Catalyst

The catalytic performance of Rh/TiO2 catalyst was investigated for the reaction of Liquefied Petroleum Gas (LPG) steam reforming with respect to the operating conditions employed. The impacts of reaction temperature, steam/C ratio, Gas Hourly Space Velocity (GHSV), and time were examined and discussed both in the absence and presence of butane in the feed. It was found that the catalytic performance is improved by increasing the reaction temperature, steam content in the feed, and/or by decreasing GHSV. In the presence of butane in the feed, the effect of H2O/C ratio on catalytic performance is prominent, whereas the opposite was observed for the effect of GHSV. The propane conversion curve decreases by adding butane in the feed, indicating that the presence of butane retards propane steam reforming. The investigation of the dynamic response of Rh/TiO2 catalyst to variations of H2O/C ratio showed that neither catalytic activity nor product selectivity is varied with time following abrupt changes of the steam/C ratio between 2 and 7. The catalyst exhibited excellent stability with time-on-stream at 500 and 650 °C. However, a reversible catalyst deactivation seems to be operable when the reaction occurs at 600 °C, resulting in a progressive decrease of propane conversion, which, however, can be completely restored by increasing the temperature to 650 °C in He flow, respectively. The long-term stability of Rh/TiO2 catalyst in the form of pellets showed that this catalyst is not only active and selective but also stable, and therefore, it is a promising catalyst for the reaction of LPG steam reforming.

Effect of Fe and Co promoters on CO methanation activity of nickel catalyst prepared by impregnation – co-precipitation method

2020 ◽  
Vol 18 (5-6) ◽  
Author(s):  
Buyan-Ulzii Battulga ◽  
Tungalagtamir Bold ◽  
Enkhsaruul Byambajav
Keyword(s):  
Synergetic Effect ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Alumina Support ◽  
Co Methanation ◽  
Temperature Range ◽  
Co Precipitation ◽  
Catalyst Distribution

AbstractNi based catalysts supported on γ-Al2O3 that was unpromoted (Ni/γAl2O3) or promoted (Ni–Fe/γAl2O3, Ni–Co/γAl2O3, and Ni–Fe–Co/γAl2O3) were prepared using by the impregnation – co-precipitation method. Their catalytic performances for CO methanation were studied at 3 atm with a weight hourly space velocity (WHSV) of 3000 ml/g/h of syngas with a molar ratio of H2/CO = 3 and in the temperature range between 130 and 350 °C. All promoters could improve nickel distribution, and decreased its particle sizes. It was found that the Ni–Co/γAl2O3 catalyst showed the highest catalytic performance for CO methanation in a low temperature range (<250 °C). The temperatures for the 20% CO conversion over Ni–Co/γAl2O3, Ni–Fe/γAl2O3, Ni–Fe–Co/γAl2O3 and Ni/γAl2O3 catalysts were 205, 253, 263 and 270 °C, respectively. The improved catalyst distribution by the addition of cobalt promoter caused the formation of β type nickel species which had an appropriate interacting strength with alumina support in the Ni–Co/γAl2O3. Though an addition of iron promoter improved catalyst distribution, the methane selectivity was lowered due to acceleration of both CO methanation and WGS reaction with the Ni–Fe/γAl2O3. Moreover, it was found that there was no synergetic effect from the binary Fe–Co promotors in the Ni–Fe–Co/γAl2O3 on catalytic activity for CO methanation.

Numerical Analysis of the Heat and Mass Transfer Characteristics in an Autothermal Methane Reformer

2010 ◽  
Vol 7 (5) ◽  
Author(s):  
Joonguen Park ◽  
Shinku Lee ◽  
Sunyoung Kim ◽  
Joongmyeon Bae
Keyword(s):  
Mass Transfer ◽  
Numerical Analysis ◽  
Heat And Mass Transfer ◽  
Steam Reforming ◽  
Space Velocity ◽  
Reaction Model ◽  
Operating Conditions ◽  
Local Thermal Equilibrium ◽  
Inlet Temperature ◽  
Transfer Characteristics

This paper discusses a numerical analysis of the heat and mass transfer characteristics in an autothermal methane reformer. Assuming local thermal equilibrium between the bulk gas and the surface of the catalyst, a one-medium approach for the porous medium analysis was incorporated. Also, the mass transfer between the bulk gas and the catalyst’s surface was neglected due to the relatively low gas velocity. For the catalytic surface reaction, the Langmuir–Hinshelwood model was incorporated in which methane (CH4) is reformed to hydrogen-rich gases by the autothermal reforming (ATR) reaction. Full combustion, steam reforming, water-gas shift, and direct steam reforming reactions were included in the chemical reaction model. Mass, momentum, energy, and species balance equations were simultaneously calculated with the chemical reactions for the multiphysics analysis. By varying the four operating conditions (inlet temperature, oxygen to carbon ratio (OCR), steam to carbon ratio, and gas hourly space velocity (GHSV)), the performance of the ATR reactor was estimated by the numerical calculations. The SR reaction rate was improved by an increased inlet temperature. The reforming efficiency and the fuel conversion reached their maximum values at an OCR of 0.7. When the GHSV was increased, the reforming efficiency increased but the large pressure drop may decrease the system efficiency. From these results, we can estimate the optimal operating conditions for the production of large amounts of hydrogen from methane.

scholarly journals Review on the Relationship Between Liquid Aerospace Fuel Composition and Their Physicochemical Properties

2020 ◽  
Author(s):  
Xiaoyu Wang ◽  
Tinghao Jia ◽  
Lun Pan ◽  
Qing Liu ◽  
Yunming Fang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
High Performance ◽  
Freezing Point ◽  
Operating Conditions ◽  
Hydrocarbon Fuels ◽  
Least Square ◽  
Fuel Properties ◽  
Molar Ratio ◽  
Fuel Composition

AbstractThe development of advanced air transportation has raised new demands for high-performance liquid hydrocarbon fuels. However, the measurement of fuel properties is time-consuming, cost-intensive, and limited to the operating conditions. The physicochemical properties of aerospace fuels are directly influenced by chemical composition. Thus, a thorough investigation should be conducted on the inherent relationship between fuel properties and composition for the design and synthesis of high-grade fuels and the prediction of fuel properties in the future. This work summarized the effects of fuel composition and hydrocarbon molecular structure on the fuel physicochemical properties, including density, net heat of combustion (NHOC), low-temperature fluidity (viscosity and freezing point), flash point, and thermal-oxidative stability. Several correlations and predictions of fuel properties from chemical composition were reviewed. Additionally, we correlated the fuel properties with hydrogen/carbon molar ratios (nH/C) and molecular weight (M). The results from the least-square method implicate that the coupling of H/C molar ratio and M is suitable for the estimation of density, NHOC, viscosity and effectiveness for the design, manufacture, and evaluation of aviation hydrocarbon fuels.

scholarly journals High catalytic performance of Fe-Ni/Palygorskite in the steam reforming of toluene for hydrogen production

2018 ◽  
Vol 226 ◽  
pp. 827-837 ◽  
Author(s):  
Xuehua Zou ◽  
Tianhu Chen ◽  
Ping Zhang ◽  
Dong Chen ◽  
Junkai He ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Catalytic Performance ◽  
Steam Reforming Of Toluene

Effect of Catalytic Distribution on the Performance of Microreactor for Hydrogen Production through Methane Steam Reforming

2010 ◽  
Vol 156-157 ◽  
pp. 873-876 ◽  
Author(s):  
Feng Wang ◽  
Zi Long An ◽  
Bo Qi ◽  
Jing Zhou
Keyword(s):  
Steam Reforming ◽  
Active Sites ◽  
Flow Direction ◽  
Space Velocity ◽  
H2 Production ◽  
Methane Steam Reforming ◽  
Reactor Performance ◽  
Methane Steam ◽  
Site Density ◽  
Availability Ratio

The effect of catalyst coating distributing on the reactor performance for methane steam reforming(MSR) was numerically investigated. In calculation, the amount catalyst loaded on the microreactor wall was fixed but the catalyst active site density was distributed according to arithmetic progression along the flow direction. Results show that it is possible to get the higher conversion of CH4 and output of H2 due to the higher availability ratio of catalyst surface active sites at this distribution. And this distribution effect is more remarkable at higher space velocity or lower reaction temperature, however, there exists an optimal distribution which can reach the highest CH4 conversion and H2 production at 900K.

Hydrogen Production by Bio-Fuel Steam Reforming at Low Reaction Temperature

2011 ◽  
Author(s):  
Tsuyoshi Maeda ◽  
Toshio Shinoki ◽  
Jiro Funaki ◽  
Katsuya Hirata
Keyword(s):  
Reaction Temperature ◽  
Steam Reforming ◽  
High Performance ◽  
Space Velocity ◽  
Ethanol Conversion ◽  
Ethanol Steam Reforming ◽  
High Hydrogen ◽  
Low Reaction Temperature ◽  
Al2o3 Catalyst ◽  
Ethanol Steam

The authors reveal the dominant chemical reactions and the optimum conditions, supposing the design of ethanol steam-reforming reactors. Specifically speaking, experiments are conducted for Cu/ZnO/Al2O3 catalyst, together with those for Ru/Al2O3 catalyst for reference. Using a household-use-scale reactor with well-controlled temperature distributions, the authors compare experimental results with chemical-equilibrium theories. It has revealed by Shinoki et al. (2011) that the Cu/ZnO/Al2O3 catalyst shows rather high performance with high hydrogen concentration CH2 at low values of reaction temperature TR. Because, the Cu/ZnO/Al2O3 catalyst promotes the ethanol-steam-reforming and water-gas-shift reactions, but does not promote the methanation reaction. So, in the present study, the authors reveal that the Ru/Al2O3 catalyst needs high TR > 770 K for better performance than the Cu/ZnO/Al2O3 catalyst, and that the Ru/Al2O3 catalyst shows lower performance at TR < 770 K. Then, the Ru/Al2O3 catalyst is considered to activate all the three reactions even at low TR. Furthermore, concerning the Cu/ZnO/Al2O3 catalyst, the authors reveal the influences of liquid-hourly space velocity LHSV upon concentrations such as CH2, CCO2, CCO and CCH4 and the influence of LHSV upon the ethanol conversion XC2H5OH, in a range of LHSV from 0.05 h−1 to 0.8 h−1, at S/C = 3.0 and TR = 520 K. And, the authors reveal the influences of the thermal profile upon CH2, CCO2, CCO, CCH4 and XC2H5OH, for several LHSV’s. To conclude, with well-controlled temperatures, the reformed gas can be close to the theory. In addition, the authors investigate the influences of S/C.

Hydrogen Production from Ethanol Steam Reforming over Ni-Cu/ZnO Catalyst

2011 ◽  
Vol 236-238 ◽  
pp. 1067-1072
Author(s):  
Li Ping Liu ◽  
Xiao Jian Ma ◽  
Peng Zhang ◽  
Ya Nan Liu
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Fixed Bed ◽  
Surface Characteristics ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Ethanol Steam Reforming ◽  
Hydrogen Yield ◽  
Ethanol Steam

Hydrogen production by ethanol steam reforming over Ni-Cu/ZnO catalyst in the temperatures range of 250-550°C was studied on a fixed bed reactor. The effects of reaction temperature and water/ethanol molar ratio on hydrogen production were investigated. The structure and surface characteristics of the catalyst were measured by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential thermal analyzer (TG-DSC). The results show that the Ni-Cu/ZnO catalyst has good catalytic performance with higher hydrogen yield of 4.87molH2/molEtOH reacted. A comparison of hydrogen production from ethanol steam reforming over Ni-Cu/ZnO catalyst with over a commercial catalyst was made in this paper.

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