Optimal catalyst activity profiles in pellets. 5. Optimization of the isothermal fixed-bed reactor

1986 ◽  
Vol 25 (3) ◽  
pp. 313-321 ◽  
Author(s):  
Massimo Morbidelli ◽  
Alberto Servida ◽  
Sergio Carra ◽  
Arvind Varma
Keyword(s):  
Catalyst Activity ◽  
Fixed Bed ◽  
Fixed Bed Reactor

scholarly journals Stable Continuous Production of γ-Valerolactone from Biomass-Derived Levulinic Acid over Zr–Al-Beta Zeolite Catalyst

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 678
Author(s):  
Clara López-Aguado ◽  
Marta Paniagua ◽  
Juan A. Melero ◽  
Jose Iglesias ◽  
Pablo Juárez ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Hydrogen Transfer ◽  
Zeolite Catalyst ◽  
Continuous Production ◽  
Catalyst Activity ◽  
Fixed Bed ◽  
Transfer Hydrogenation ◽  
Fixed Bed Reactor ◽  
Beta Zeolite ◽  
Thermal Regeneration

The one-pot conversion of biomass-derived platform molecules such as levulinic acid (LA) and furfural (FAL) into γ-valerolactone (GVL) is challenging because of the need for adequate multi-functional catalysts and high-pressure gaseous hydrogen. As a more sustainable alternative, here we describe the transfer hydrogenation of LA to GVL using isopropanol as a hydrogen donor over a Zr-modified beta zeolite catalyst in a continuous fixed-bed reactor. A stable sustained production of GVL was achieved from the levulinic acid, with both high LA conversion (ca. 95%) and GVL yield (ca. 90%), for over at least 20 days in continuous operation at 170 °C. Importantly, the small decay in activity can be advantageously overcome by the means of a simple in situ thermal regeneration in the air atmosphere, leading to a complete recovery of the catalyst activity. Key to this outstanding result is the use of a Zr-modified dealuminated beta zeolite with a tailored Lewis/Brønsted acid sites ratio, which can synergistically catalyze the tandem steps of hydrogen transfer and acid-catalyzed transformations, leading to such a successful and stable production of GVL from LA.

Dynamics and Control of an Adiabatic Fixed Bed Reactor with Varying Catalyst Activity

1986 ◽  
Vol 19 (15) ◽  
pp. 267-272 ◽  
Author(s):  
L. Goldschmidt ◽  
L. Hallager ◽  
S.B. Jorgensen
Keyword(s):  
Catalyst Activity ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Dynamics And Control ◽  
And Control

Optimal catalyst activity distribution in fixed-bed reactor with catalyst deactivation

1989 ◽  
Vol 54 (2) ◽  
pp. 375-387 ◽  
Author(s):  
Jozef Markoš ◽  
Alena Brunovská
Keyword(s):  
Catalyst Deactivation ◽  
Active Catalyst ◽  
Catalyst Activity ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Catalytic Reactor ◽  
Reactor Performance ◽  
Thiele Modulus ◽  
Activity Distribution ◽  
Parameter Ratio

In this paper the influence of the active catalyst location in a pellet on fixed-bed catalytic reactor performance is described. The optimal activity distribution as a function of an economic parameter (ratio of product and catalyst costs), Thiele modulus and Damkohler number is estimated.

scholarly journals Aldol Condensation of Cyclohexanone and Furfural in Fixed-Bed Reactor

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1068
Author(s):  
Zdeněk Tišler ◽  
Pavla Vondrová ◽  
Kateřina Hrachovcová ◽  
Kamil Štěpánek ◽  
Romana Velvarská ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Heterogeneous Catalysts ◽  
Mixed Oxides ◽  
Aldol Condensation ◽  
Condensation Reaction ◽  
Catalyst Activity ◽  
Fixed Bed ◽  
Chemical Properties ◽  
Fixed Bed Reactor ◽  
Molar Ratio

Aldol condensation reaction is usually catalysed using homogeneous catalysts. However, the heterogeneous catalysis offers interesting advantages and the possibility of cleaner biofuels production. Nowadays, one of the most used kinds of heterogeneous catalysts are hydrotalcites, which belong to a group of layered double hydroxides. This paper describes the aldol condensation of cyclohexanone (CH) and furfural (F) using Mg/Al mixed oxides and rehydrated mixed oxides in order to compare the catalyst activity after calcination and rehydration, as well as the possibility of its regeneration. The catalysts were synthesized by calcination and subsequent rehydration of the laboratory-prepared and commercial hydrotalcites, with Mg:Al molar ratio of 3:1. Their structural and chemical properties were determined by several analytical methods (inductively coupled plasma analysis (ICP), X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), specific surface area (BET), thermogravimetric analysis (TGA), temperature programmed desorption (TPD)). F-CH aldol condensation was performed in a continuous fixed-bed reactor at 80 °C, CH:F = 5:1, WHSV 2 h−1. The rehydrated laboratory-prepared catalysts showed a 100% furfural conversion for more than 55 h, in contrast to the calcined ones (only 24 h). The yield of condensation products FCH and F2CH was up to 68% and 10%, respectively. Obtained results suggest that Mg/Al mixed oxides-based heterogeneous catalyst is suitable for use in the aldol condensation reaction of furfural and cyclohexanone in a fixed-bed reactor, which is an interesting alternative way to obtain biofuels from renewable sources.

scholarly journals Kinetic Model of Crude Palm Oil Hydrocracking Over Ni/Mo ZrO2–Pillared Bentonite Catalyst

2019 ◽  
Vol 64 (2) ◽  
pp. 238-247 ◽  
Author(s):  
Hasanudin Hasanudin ◽  
Addy Rachmat ◽  
Muhammad Said ◽  
Karna Wijaya
Keyword(s):  
Kinetic Model ◽  
Palm Oil ◽  
Rate Constants ◽  
Catalyst Activity ◽  
Fixed Bed ◽  
Diesel Oil ◽  
Fixed Bed Reactor ◽  
Crude Palm Oil ◽  
Reaction Models ◽  
Oil Gas

Crude Palm Oil hydrocrcaking has been carried out over Ni/Mo ZrO2–pillared bentonite catalyst in a fixed bed reactor. Crude Palm Oil hydrocracking over Ni/Mo ZrO2–pillared bentonite catalyst formed 3 products i.e. gas, oil and coke. The oil product from Crude Palm Oil hydrocracking was analyzed by using gas chromatography to determine its composition. Three types of fraction were classified i.e. gasoline, kerosene and diesel oil. In this research, the focused of the study is of hydrocracking kinetics by using lump kinetic models. The kinetic model was solved by using the software MATLAB R2018b involves the effect of catalyst activity on the reaction rate. The results of the kinetic study show that the 4-lump (Crude Palm Oil, gas coke and oil) and 6-lump reaction models (Crude Palm Oil, gas, coke, gasoline, kerosene and diesel) can be used to explain the Crude Palm Oil hydrocracking over Ni/Mo ZrO2–pillared bentonite catalyst. The 4-lump kinetic model has 5 rate constants and the 6-lump kinetic model has 14 rate constants.

Hydrogenation of Model Compounds Catalyzed by MCM-41-Supported Nickel Phosphide

2013 ◽  
Vol 864-867 ◽  
pp. 366-372 ◽  
Author(s):  
Liang Yan Xia ◽  
Zhi Xiang Xia ◽  
Wei Tang ◽  
Hong Yan Wang ◽  
Meng Xiang Fang
Keyword(s):  
Catalyst Activity ◽  
Fixed Bed ◽  
Volume Ratio ◽  
Space Velocity ◽  
Fixed Bed Reactor ◽  
Nickel Phosphide ◽  
Great Performance ◽  
Different Temperatures ◽  
Temperature Programmed ◽  
Mcm 41

MCM-41 supported nickel phosphide (Ni2P/MCM-41) was prepared by temperature-programmed reduction of the corresponding phosphate. The catalyst activity for hydrodeoxygenation (HDO), hydrodearomatization (HDA), hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) was investigated in a fixed bed reactor. O-cresol HDO, 1-methylnaphthalene HDA, quinoline HDN, dibenzothiophene HDS and simultaneous HDO, HDA, HDN, HDS were respectively tested at different temperatures with constant pressure (6.0 MPa), liquid hourly space velocity (3.0 h-1), hydrogen-to-oil volume ratio (600:1). The results indicate that Ni2P /MCM-41 catalyst has great performance on HDO, HDA, HDN, HDS in single model compound reactions. O-cresol and DBT are almost completely transformed at 375°C, while 1-methylnaphthalene and quinoline reach the highest conversion at 300°C. In the simultaneous reactions, quinoline shows higher conversion by competitive adsorption on the catalyst hydrogenation sites, leading to conversion decrease of o-cresol, 1-methylnaphthalene and DBT.

Solid P-W Keggin Heteropoly Compounds as Effective Catalysts for the Sorption-Decomposition of NOX

2011 ◽  
Vol 233-235 ◽  
pp. 355-358
Author(s):  
Rui Wang ◽  
Tao Ma ◽  
Dan Wu ◽  
Vladimir N. Korchak
Keyword(s):  
Catalyst Activity ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Heteropoly Compounds ◽  
Marked Enhancement ◽  
Normal Particle ◽  
Ir Analysis ◽  
Internal And External Factors ◽  
First Time ◽  
Decomposition Of No

Several new heteropoly compounds catalysts with pronounced activities in NOx conversion via adsorption-decomposition process in a fixed-bed reactor were evaluated concerning the principal internal and external factors having marked effects on the process of adsorption. Results showed that substitution of H+ in HPW (H3PW12O40•6H2O) by NH4+ results in marked enhancement of the catalyst activity, however, substitution of coordination atom W in the [PW12O40]3- anion by one or more Mo atoms tends to lower the catalyst activity and such tendency deepens with the increase in the Mo atom numbers introduced. It is for the first time that the nano-effect was observed with nano (NH4)3PW12O40 catalyst, in which a 1.6% to 10.6% enhancement in NOx adsorption efficiency was obtained in comparison with the same catalyst in normal particle size. By IR analysis, NO was found to be adsorbed via interaction with the proton of HPW structure. With the aid of GC-MS analysis, the process effectiveness for NOx decomposition into N2 was confirmed.

scholarly journals Preparation of Pt-Zeolite Catalyst for Conversion of n-Octanol

2010 ◽  
Vol 1 (2) ◽  
pp. 90-97
Author(s):  
I Made Sadiana ◽  
Iip Izul Falah ◽  
Triyono Triyono
Keyword(s):  
Flow Rate ◽  
Zeolite Catalyst ◽  
Catalyst Activity ◽  
Fixed Bed ◽  
Hydrogen Gas ◽  
Fixed Bed Reactor ◽  
Activity Increase ◽  
Activity Test ◽  
Nitrogen Stream ◽  
Oxygen Gas

Pt-zeolite catalyst has been prepared by immersing a sample of zeolite in PtCl4 solution. After separation, the sample was dried and calcinated at 550 °C for 4 hours under nitrogen stream. Furthermore, the sample was oxidized with oxygen gas at 350 °C for 2 hours and reduced with hydrogen gas at 400 °C for 2 hours. Total amount of impregnated metal, acidity and surface are of the samples were determined by using atomic absorption spectrophotometric, gravimetric and gas sorption methods, respectively. The activity test was done in a fixed bed reactor and the results of the reaction were analyzed by using gas chromatograph. The result of the characterization showed that the higher total amount of impregnated metal, the lower the surface area and total volume of pores. The acidity and the catalyst activity increase with the increasing of the total amount of impregnated metal. The flow rate of feed and temperature reaction also influence yield conversion. The optimum yield of n-octanol conversion was obtained at 400 °C with the showest flow rate of n-octanol and flow rate of H2 gas was equal to 40 mL/minute.

scholarly journals Pembuatan dan uji aktivitas katalis htsc berbasis besi oksida

2018 ◽  
Vol 6 (3) ◽  
pp. 699
Author(s):  
Fitri Rumiani ◽  
S Subagjo
Keyword(s):  
High Temperature ◽  
Surface Area ◽  
Catalyst Surface ◽  
Catalyst Activity ◽  
Nitrate Solution ◽  
Fixed Bed ◽  
Great Influence ◽  
Temperature Shift ◽  
Fixed Bed Reactor ◽  
Preparation Procedure

High temperature shift conversion is a water gas shift reaction using water to produce carbon dioxide and hydrogen in high temperature (370-400oC). The aim of this research is examining the preparation procedure of HTSC catalyst. The catalyst made by Co-precipitation method of Fe and Cr nitrate solution with Na2CO3 as precipitating agent. The specific surface area of catalyst is determined by BET method. The crystal structure was analyzed by XRD method. The catalyst activity was evaluated in the fixed bed reactor on laboratory scale with 370oC and 1 atm. The result shows that the preparation procedure of HTSC ITB catalyst is reproducible. Based on the preparation procedure, calcinations temperature has a great influence to the catalyst surface area. The calcinations temperature at 300oC gave the highest catalyst surface area (198 m2/g), and it is comparable with the surface area claimed by Jennings (200 m2/g). The catalyst has also the highest activity by means of CO conversion resulted by the catalyst activity test (86%) which is larger than commercial catalyst conversion (81%)Keywords : Activity, Catalyst based on Fe/Cr, HTSC, Precipitation Abstrak High temperature shift conversion (HTSC) merupakan reaksi pergeseran CO menggunakan air menjadi CO2 dun H2 yang diselenggarakan pada temperatur tinggi (370-400oC). Penelitian ini bertujuan untuk mendapatkan resep dan prosedur pembuatan katalis HTSC. Katalis dibuat dengan metode kopresipitasi larutan garam nitrat dart Fe dan Cr dengan Na2CO3 sebagai senyawa pengendap. Untuk mengetahui keberhasilan penelitian ini, dilakukan penentuan luas permukaan, struktur kristal, dan aktivitas katalis yang kemudian dibandingkan dengan katalis komersial. Luas permukaan spesiftk diukur menggunakan metode BET, sedangkan struktur kristal dianalisis menggunakan XRD. Uji aktivitas katalis dilakukan dalam reaktor fixed bed skala laboratorium pada 370oC dan 1 atm. Hasil penelt.tian menunjukkan bahwa pelaksanaan prosedur pembuatan katalis HTSC ITB sudah dapat diulangi dengan hasil yang sama (reproducible). Berdasarkan prosedur tersebut, temperatur kalsinasi sangat berpengaruh terhadap lnas permukaan katalis. Dalam rentang temperatur yang dipelajari (300-400oC), kalsinasi pada temperatur 300oC menghasilkan katalis dengan luas permukaan paling tinggi yaitu 192-198 m2/g. Makin tinggi luas permukaan katalis yang dihasilkan, makin tinggi aktivitas katalis tersebut. Katalis dengan luas permukaan 192-198 m2/g menghasilkan aktivitas paling tinggi, konversi CO yang dihasilkan adalah 86 %, sedikit lebih besar dari konversi katalis komersial (81 %).Kata Kunci : Aktivitas, HTSC, Katalis berbasis Fe/Cr, Prespitasi

PdIn Catalysts in a Continuous Fixed Bed Reactor for the Nitrate Removal from Groundwater

2019 ◽  
Vol 17 (6) ◽  
Author(s):  
F. A. Marchesini ◽  
G. Mendow ◽  
N. P. Picard ◽  
F. M. Zoppas ◽  
V. S. Aghemo ◽  
...  
Keyword(s):  
Active Sites ◽  
Catalyst Deactivation ◽  
Catalytic Reduction ◽  
Bubble Column ◽  
Catalyst Activity ◽  
Nitrate Removal ◽  
Fixed Bed ◽  
High Water ◽  
Fixed Bed Reactor ◽  
Water Volume

Abstract The ground water (GW) is a real sample of water which contains nitrates (81 mg/L), carbonates and sulphates. This sample was treated by catalytic reduction in a bubble column fixed-bed reactor. The reaction conditions were room temperature and atmospheric pressure, and hydrogen was used as reducing agent. A comparison between the catalytic activity of Pd,In/SiO2 and Pd,In/Al2O3 catalysts was performed, giving the latter the best results regarding the nitrate conversion and the former the selectivity to nitrogen. Synthetic water containing nitrates (SW) and the groundwater (GW) with high salinity (81 mg/L nitrates) and humic acid content were treated in these conditions using HCl and CO2 as acidifiers. When the SW was acidified with CO2 at an H2 flow (2.17 mL/min), more than 50 % of conversion was obtained with an ammonia and nitrite concentrations of 0.44 and 0.92 ppm respectively. These results reached the level established by the WHO and the USEPA. However, both Pd,In/SiO2 and Pd,In/Al2O3 catalysts showed evidence of some deactivation process. This deactivation was higher in the GW sample, possibly due to the presence of Ca+2 and Mg+2 cations that precipitate on the active sites, and/or the presence of humic acids. The characterization studies indicated that, after the reaction, the composition of the metal phases was modified, specifically on their surface. As the catalyst activity is related to surface ratio Pd/In, a relative increase in the concentration of Pd decreases the activity and causes changes in the selectivity to N2. Some sintering of the metal particles was also observed to contribute to catalyst deactivation. Nevertheless, promising results were obtained since a high water volume could be treated with a relatively low amount of low metal loading catalysts.

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