scholarly journals Analysis and Model-Based Description of the Total Process of Periodic Deactivation and Regeneration of a VOx Catalyst for Selective Dehydrogenation of Propane

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1374
Author(s):  
Andreas Brune ◽  
Andreas Seidel-Morgenstern ◽  
Christof Hamel
Keyword(s):  
Catalyst Deactivation ◽  
Process Development ◽  
Coke Formation ◽  
Fixed Bed ◽  
Reaction Network ◽  
Fixed Bed Reactor ◽  
Side Reactions ◽  
Model Based ◽  
Total Process

This study intends to provide insights into various aspects related to the reaction kinetics of the VOx catalyzed propane dehydrogenation including main and side reactions and, in particular, catalyst deactivation and regeneration, which can be hardly found in combination in current literature. To kinetically describe the complex reaction network, a reduced model was fitted to lab scale experiments performed in a fixed bed reactor. Additionally, thermogravimetric analysis (TGA) was applied to investigate the coking behavior of the catalyst under defined conditions considering propane and propene as precursors for coke formation. Propene was identified to be the main coke precursor, which agrees with results of experiments using a segmented fixed bed reactor (FBR). A mechanistic multilayer-monolayer coke growth model was developed to mathematically describe the catalyst coking. Samples from long-term deactivation experiments in an FBR were used for regeneration experiments with oxygen to gasify the coke deposits in a TGA. A power law approach was able to describe the regeneration behavior well. Finally, the results of periodic experiments consisting of several deactivation and regeneration cycles verified the long-term stability of the catalyst and confirmed the validity of the derived and parametrized kinetic models for deactivation and regeneration, which will allow model-based process development and optimization.

Kinetic Modelling of Propane Dehydrogenation over a Pt–Sn/hierarchical SAPO-34 Zeolite Catalyst, Including Catalyst Deactivation

2017 ◽  
Vol 42 (4) ◽  
pp. 344-360
Author(s):  
Milad Komasi ◽  
Shohreh Fatemi ◽  
Seyed Hesam Mousavi
Keyword(s):  
Catalyst Deactivation ◽  
Kinetic Modelling ◽  
Coke Formation ◽  
Fixed Bed ◽  
Reaction Network ◽  
Normal Pressure ◽  
Fixed Bed Reactor ◽  
Propane Dehydrogenation ◽  
Coke Deposition ◽  
Formation Kinetic

Pt–Sn/hierarchical SAPO-34 was synthesised and kinetically modelled as an efficient and selective catalyst for propylene production through propane dehydrogenation. The kinetics of the reaction network were studied in an integral fixed-bed reactor at three temperatures of 550, 600 and 650 °C and weight hourly space velocities of 4 and 8 h−1 with a feed containing hydrogen and propane with relative molar ratios of 0.2, 0.5 and 0.8, at normal pressure. The experiments were performed in accordance with the full factorial experimental design. The kinetic models were constructed on the basis of different mechanisms and various deactivation models. The kinetics and deactivation parameters were simultaneously predicted and optimised using genetic algorithm optimisation. It was further proven that the Langmuir–Hinshelwood model can well predict propane dehydrogenation kinetics through lumping together all the possible dehydrogenation steps and also by assuming the surface reaction as the rate-determining step. A coke formation kinetic model has also shown appropriate results, confirming the experimental data by equal consideration of both monolayer and multilayer coke deposition kinetic orders and an exponential deactivation model.

The Kinetics Model and Fixed Bed Reactor Simulation of Cu Catalyst for Acetylene Hydrochlorination

2017 ◽  
Vol 15 (4) ◽  
Author(s):  
Hao Xu ◽  
Jiangkun Si ◽  
Guohua Luo
Keyword(s):  
Catalyst Deactivation ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Acetylene Hydrochlorination ◽  
Cu Catalyst ◽  
Long Term Performance ◽  
Reaction Activation Energy ◽  
Term Performance ◽  
Pvc Industry

Abstract Acetylene hydrochlorination is an important reaction for vinyl chloride monomer (VCM) production in China. Non-mercury catalysts and related green processes are the urgently needed technologies in this field. In this work, reaction kinetics and a model of fixed bed reactor (FBR) with Cu/AC (activated carbon) catalyst for acetylene hydrochlorination were constructed and verified by experiments. First, the influence of external and internal diffusion was studied and eliminated. Then, reaction activation energy and reaction order to each reactant were determined. Next, catalyst deactivation was considered and the simulation of an FBR including conversion, temperature and pressure distribution was established. Results were consistent with experimental data. The model provided quantitative parameters for evaluating the activity and lifetime of catalysts, thereby establishing criteria for catalyst evaluation. Industrial long-term performance of catalysts was predicted by limited laboratory short-term data. Finally, previous publication results were gathered and compared. The study provided valuable guidance for non-mercury catalyst in PVC industry and other similar systems.

scholarly journals Co-digestion of Oil Palm Trunk Hydrolysate and Slaughterhouse Wastewater for Biohydrogen Production in a Fixed Bed Reactor by Immobilized Thermoanaerobacterium thermosaccharolyticum KKU19 on Expanded Clay

2021 ◽  
Vol 9 ◽  
Author(s):  
Sontaya Khamtib ◽  
Sureewan Sittijunda ◽  
Tsuyoshi Imai ◽  
Alissara Reungsang
Keyword(s):  
Oil Palm ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Hydrogen Yield ◽  
Support Material ◽  
Slaughterhouse Wastewater ◽  
Term Operation ◽  
Oil Palm Trunk ◽  
Thermoanaerobacterium Thermosaccharolyticum

The goal of this study was to evaluate the use of expanded clay as a support material for Thermoanaerobacterium thermosaccharolyticum KKU19 to produce hydrogen from oil palm trunk hydrolysate (OPT) and slaughterhouse wastewater (SHW) in a fixed-bed reactor (FBR) under non-sterile conditions. The effects of hydraulic retention time (HRT) on the performance of the FBR were also investigated. The FBR was operated at an OPT hydrolysate to SHW ratio of 2.55:1 (v:v), 60°C, initial pH 6.5, and 1.2 mg (as total volatile solids/g expanded clay) of T. thermosaccharolyticum KKU19 immobilized on expanded clay. A maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 7.15 ± 0.22 L/L day and 234.45 ± 5.14 mL H2/g-COD, respectively, were obtained at an HRT of 6 h. Long-term operation of FBR at 6 h HRT indicated that expanded clay efficiently immobilizes T. thermosaccharolyticum KKU19, for which an HPR of 6.82 ± 0.56 L H2/L day, and an HY of 231.99 ± 19.59 mL H2/g-COD were obtained. Furthermore, the COD removal efficiency of 30% obtained under long-term operation was comparable to that under short-term operation at an HRT of 6 days. Butyric and acetic acids were the main soluble metabolite products, thereby indicating a butyrate–acetate type fermentation. Our findings indicate that expanded clay is an effective support material that contributes to the protection of microbial cells and can be used for long-term operation.

scholarly journals Long-term performance and microbial dynamics of an up-flow fixed bed reactor established for the biodegradation of fluorobenzene

2006 ◽  
Vol 71 (4) ◽  
pp. 555-562 ◽  
Author(s):  
M. F. Carvalho ◽  
R. Ferreira Jorge ◽  
C. C. Pacheco ◽  
P. De Marco ◽  
I. S. Henriques ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Microbial Dynamics ◽  
Long Term Performance ◽  
Term Performance

Model-Based Experimental Analysis of a Fixed-Bed Reactor for Catalytic SO2Oxidation

2009 ◽  
Vol 48 (11) ◽  
pp. 5165-5176 ◽  
Author(s):  
J. C. Schöneberger ◽  
H. Arellano-Garcia ◽  
G. Wozny ◽  
S. Körkel ◽  
H. Thielert
Keyword(s):  
Experimental Analysis ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Model Based

scholarly journals Hydrogen Generation from Catalytic Steam Reforming Bio-Oil Model Compound—Acetic Acid Employing Ni/attapulgite Catalysts Prepared with Different Preparation Methods

2016 ◽  
Author(s):  
Yishuang Wang ◽  
Mingqiang Chen ◽  
Tian Liang ◽  
Jie Yang ◽  
Zhonglian Yang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Steam Reforming ◽  
Catalyst Deactivation ◽  
Hydrogen Generation ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Precipitation Method ◽  
Impregnation Method ◽  
Bio Oil ◽  
Catalytic Steam Reforming

In this research, catalytic steam reforming acetic acid derived from the aqueous portion of bio-oil for hydrogen production was investigated by using different Ni/ATC (Attapulgite Clay) catalysts prepared by precipitation, impregnation and mechanical blending methods. The fresh and reduced catalysts were characterized by XRD, N2 adsorption-desorption, TEM and H2-TPR. The comprehensive results demonstrated that the interaction between active metallic Ni and ATC carrier was significantly improved in Ni/ATC catalyst prepared by precipitation method, and in which the mean Ni particle size was the smallest (~13 nm) resulted in the highest metal dispersion (7.5%). The catalytic performance of the three catalysts was evaluated through the process of steam reforming of acetic acid in a fixed-bed reactor under atmospheric pressure at two different temperatures, such as 550 ℃ and 650 ℃. Results showed that the Ni/ATC (PM-N/ATC) prepared by precipitation method, achieved the highest H2 yield of ~82% and little lower acetic acid conversion efficiency of ~85% than that (~95%) of Ni/ATC (IM-NATC) prepared by impregnation method. In addition, the deactivation catalysts after reaction for 4 h were analyzed by XRD, TGA-DTG and TEM, which demonstrated that the catalyst deactivation was not caused by the amount of carbon deposition, but owed to the significant agglomeration and sintering of Ni particles in the carrier.

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.

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