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Numerical simulation of fixed bed reactor for oxidative coupling of methane over monolithic catalyst

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Chinese Journal of Chemical Engineering 2015年第10期23卷 1627-1633页

作者：张照郭紫琪季生福 State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

A three-dimensional geometric model was set up for the oxidative coupling of methane(OCM) fixed bed reactor loaded with Na_3PO_4-Mn/SiO_2/cordierite monolithic catalyst,and an improved Stansch kinetic model was established to calculate the OCM reactions using the computational fluid dynamics method and Fluent *** simulation conditions were completely the same with the experimental conditions that the volume velocity of the reactant is 80 ml·min^(-1) under standard state,the CH_4/O_2 ratio is 3 and the temperature and pressure is800 ℃ and 1 atm,*** contour of the characteristic parameters in the catalyst bed was analyzed,such as the species mass fractions,temperature,the heat flux on side wall surface,pressure,fluid density and *** results showed that the calculated values matched well with the experimental values on the conversion of CH4 and the selectivity of products(C_2H_6,C_2H_4,CO,CO_2 and H_2) in the reactor outlet with an error range of±4%.The mass fractions of CH_4 and O_2 decreased from 0.600 and 0.400 at the catalyst bed inlet to 0.445 and0.120 at the outlet,where the mass fractions of C_2H_6,C_2H_4,CO and CO_2 were 0.0245,0.0460,0.0537 and 0.116,*** to the existence of laminar boundary layer,the mass fraction contours of each species bent upwards in the vicinity of the boundary *** volume of OCM reaction was changing with the proceeding of reaction,and the total moles of products were greater than *** flow field in the catalyst bed maintained constant temperature and *** fluid density decreased gradually from 2.28 kg·m^(-3) at the inlet of the catalyst bed to 2.18 kg·m^(-3) at the outlet of the catalyst bed,while the average velocity magnitude increased from 0.108 m·s-1 to 0.120 m·s^(-1).

关键词： Numerical simulation fixed bed reactor Computational fluid dynamics Oxidative coupling of methane Monolithic catalyst

Improved Generalized Predictive Control Algorithm with Offline and Online Identification and Its Application to fixed bed reactor

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Chinese Journal of Chemical Engineering 2003年第1期11卷 49-54页

作者：余世明王海清 Instituteof Intelligent Information System Zhejiang University of Technology Instituteof Industrial Process Control Zhejiang University

An improved generalized predictive control algorithm is presented in thispaper by incorporating offline identification into online identification. Unlike the existinggeneralized predictive control algorithms, the proposed approach divides parameters of a predictivemodel into the time invariant and time-varying ones, which are treated respectively by offline andonline identification algorithms. Therefore, both the reliability and accuracy of the predictivemodel are improved. Two simulation examples of control of a fixed bed reactor show that this newalgorithm is not only reliable and stable in the case of uncertainties and abnormal disturbances,but also adaptable to slow time varying processes.

关键词： generalized predictive control offline identification onlineidentification fixed bed reactor

Conversion of Non-a-Tocopherols to a-Tocopherol in a fixed bed reactor

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Chinese Journal of Chemical Engineering 2004年第4期12卷 561-565页

作者：陈明吴彩娟任其龙杨亦文黄梅 National Laboratory of Secondary Resources Chemical Engineering Zhejiang University Hangzhou 310027 China National Laboratory of Secondary Resources Chemical Engineering Zhejiang University Hangzhou 310027 Chinaince a-tocopherol has special biological and nutritional activities it is important to convert non-a-tocopherols to a-tocopherol. This paper focuses on the effects of residence time pressure temperature and the mass ratio of formaldehyde to tocopherols on the content of a-tocopherol the conversion of non-a-tocopherols the selectivity and yield of a-tocopherol in a fixed-bed reactor. The reactor is made from φ12 (I.D.)×360mm stainless steel pipe. It is packed with a mixture of 5% Pd/C and cation exchange resin catalysts. Preliminary results indicated the suitable operation conditions are pressure 5.0 MPa temperature 180℃ and mass ratio of formaldehyde to tocopherols 2.0. A product of more than 50% a-tocopherol content has been obtained by using 88.85% mixed tocopherols as raw material.

Since a-tocopherol has special biological and nutritional activities, it is important to convert non-a-tocopherols to a-tocopherol. This paper focuses on the effects of residence time, pressure, temperature and the mass ratio of formaldehyde to tocopherols on the content of a-tocopherol, the conversion of non-a-tocopherols, the selectivity and yield of a-tocopherol in a fixed-bed reactor. The reactor is made from φ12 (I.D.)×360mm stainless steel pipe. It is packed with a mixture of 5% Pd/C and cation exchange resin catalysts. Preliminary results indicated the suitable operation conditions are pressure 5.0 MPa, temperature 180℃, and mass ratio of formaldehyde to tocopherols 2.0. A product of more than 50% a-tocopherol content has been obtained by using 88.85% mixed tocopherols as raw material.

关键词： tocopherol fixed bed reactor conversion

Kinetic Study of Methanol Dehydration to Dimethyl Ether in Catalytic Packed bed reactor over Resin

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Journal of Materials Science and Chemical Engineering 2022年第6期10卷 45-58页

作者： Ghassan J. Hadi Arkan J. Hadi Technical Institute Northern Technical University Adour Iraq College of Engineering Soran University Erbil Iraq

Dimethyl ether (DME) is considered as a significant fuel alternative with a critical manufacturing process. Only a few authors have presented the kinetic analysis of attractive and alternative catalysts to Al2O3 and/or zeolite in DME production, despite the fact that there is a large library of kinetic studies for these commercial catalysts. The purpose of this research was to contribute to this direction by conducting a catalytic test to determine kinetic parameters for methanol dehydration over sulfonic acid catalysts (resin). However, due to the relevance of the mathematical description of this process in the industry was also studied, a study of kinetics parameters and mathematical modeling of methanol dehydration in an atmospheric gas phase in a fixed bed reactor with a temperature range (90°C - 120°C) was examined. The Langmuir-Hinshelwood (L-H) model provides the best fit to experimental data, with an excellent R2 = 0.9997, and the experimental results were compared to those predicted by these models with very small deviations. The kinetic parameters were found to be in good agreement with the Arrhenius equation, with acceptable straight-line graphs. The activation energy E was computed and found to be 27.66 kJ/mole, with an average variation of 0.32 percent between the predicted and calculated results. Simple mathematical continuum models (plug flow reactor PFR) showed an acceptable agreement with the experimental data.

关键词： Catalyst Dimethyl Ether fixed bed reactor Dehydration Modelling

Production of single-walled carbon nanotubes from methane over Co-Mo/MgO nanocatalyst:A comparative study of fixed and fluidized bed reactors

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Journal of Natural Gas Chemistry 2011年第4期20卷 372-376页

作者： Alimorad Rashidi Roghayeh Lotfi Ehsaneh Fakhrmosavi Masoud Zare Nanotechnology Research Center Research Institute of Petroleum Industry(R.I.P.I.)West Blvd.of Azadi Sport Complex

In this study,the performances of fixed and fluidized bed reactors in the production of single-walled carbon nanotubes（SWNTs）have been *** both reactors,single-walled carbon nanotubes were grown by catalytic chemical vapor decomposition（CCVD）of methane over Co-Mo/MgO nanocatalyst under two different operating *** synthesized samples were characterized by TEM,TGA and Raman *** is found that the performance of a fluidized bed in the synthesis of carbon nanotubes is much better than that of a fixed *** quality of carbon nanotubes obtained from the fluidized bed was significantly higher than that from the fixed bed and the former one with the ID/IG ratio of 0.11 while the latter one with the ID/IG ratio of ***,the yield of SWNTs in the fluidized bed was 92 wt%,while it was 78 wt%in the fixed *** advantages of fluidized bed reactors for the synthesis of carbon nanotubes can be attributed to more available space for the growth of carbon nanotubes and more uniform temperature and concentration profiles.

关键词： single-walled carbon nanotubes chemical vapor deposition fixed bed reactor fluidized bed reactor

Effects of temperature on pyrolysis products of oil sludge

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Frontiers of Environmental Science & Engineering 2008年第1期2卷 8-14页

作者： Jianguo LIU Wei SONG Yongfeng NIE Department of Environmental Science and Engineering Tsinghua UniversityBeijing 100084China

Temperature is the determining factor of pyro-lysis,which is one of the alternative technologies for oil sludge *** effects of final operating temper-ature ranging from 350 to 550uC on pyrolysis products of oil sludge were studied in an externally-heating fixed bed *** an increase of temperature,the mass fraction of solid residues,liquids,and gases in the final product is 67.00%–56.00%,25.60%–32.35%,and 7.40%–11.65%,and their corresponding heat values are 34.4–13.8 MJ/kg,44.41–46.6 MJ/kg,and 23.94–48.23 MJ/Nm 3,*** mass and energy tend to shift from solid to liquid and gas phase(especially to liquid phase)during the process,and the optimum temperature for oil sludge pyrolysis is *** liquid phase is mainly com-posed of alkane and alkene(C_(5)–C_(29)),and the gas phase is dominantly HC S and H 2.

关键词： oil sludge pyrolysis temperature fixed bed reactor pyrolysis products

Comprehensive study of nanostructured supports with high surface area for Fischer-Tropsch synthesis

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Journal of Energy Chemistry 2013年第4期22卷 573-581页

作者： Somayeh Farzad Ali Haghtalab Alimorad Rashidi Department of Chemical Engineering Tarbiat Modares University Nanotechnology Research Center Research Institute of Petroleum Industry (RIPI)

An extensive study of Fischer-Tropsch synthesis on nanostructure supports with high surface area such as nanostructure -y-alumina, single wall carbon nanotubes （SWNTs）, and the hybrid of SWNTs/nanostructure -y-alumina has been investigated. The nanostructure γ-alumina was promoted with lanthanum to obtain better performance of catalyst and 15 wt% cobalt loading was the basis of our investigation. Fischer- Tropsch synthesis was performed in a fixed bed reactor under different reaction conditions （220-240 ℃, 15-25 bar, H2/CO ratio of 2, GHSV of 900-1400） in order to study the effects of temperature, pressure and gas hourly space velocity （GHSV） changes on hydrocarbon selec- tivity and catalyst activity. The catalysts were extensively characterized by different methods including X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, inductively coupled plasma （ICP）, hydrogen （H2） chemisorption and temperature-programmed reduction （TPR）. The results showed that the yield of hybrid supported catalyst （55.4%） is higher than that of nanos- tructure -y-alumina supported catalyst （55.0%） and lower than that of SWNTs supported cobalt catalyst （71.0%）. The hybrid supported catalyst showed higher reduction degree and dispersion of cobalt particles. The temperature, pressure and GHSV effects on hybrid supported catalyst were studied and results showed that higher pressure favors the chain growth and temperature increase leads to the increases in methane selec- tivity and CO conversion. Higher hydrocarbon selectivity and CO conversion showed positive relationship with increasing GHSV while lower hydrocarbon selectivity diminishes.

关键词： Fischer-Tropsch synthesis single wall carbon nanotubes nanostructure γ-Al2O3 cobalt catalyst fixed bed reactor