scholarly journals Decomposition of Additive-Free Formic Acid Using a Pd/C Catalyst in Flow: Experimental and CFD Modelling Studies

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 341
Author(s):  
Sanaa Hafeez ◽  
Felipe Sanchez ◽  
Sultan M. Al-Salem ◽  
Alberto Villa ◽  
George Manos ◽  
...  
Keyword(s):  
Experimental Data ◽  
Formic Acid ◽  
Catalyst Deactivation ◽  
Fluid Dynamic ◽  
Fixed Bed ◽  
Reaction System ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Fresh Sample ◽  
Modelling Studies

The use of hydrogen as a renewable fuel has gained increasing attention in recent years due to its abundance and efficiency. The decomposition of formic acid for hydrogen production under mild conditions of 30 °C has been investigated using a 5 wt.% Pd/C catalyst and a fixed bed microreactor. Furthermore, a comprehensive heterogeneous computational fluid dynamic (CFD) model has been developed to validate the experimental data. The results showed a very good agreement between the CFD studies and experimental work. Catalyst reusability studies have shown that after 10 reactivation processes, the activity of the catalyst can be restored to offer the same level of activity as the fresh sample of the catalyst. The CFD model was able to simulate the catalyst deactivation based on the production of the poisoning species CO, and a sound validation was obtained with the experimental data. Further studies demonstrated that the conversion of formic acid enhances with increasing temperature and decreasing liquid flow rate. Moreover, the CFD model established that the reaction system was devoid of any internal and external mass transfer limitations. The model developed can be used to successfully predict the decomposition of formic acid in microreactors for potential fuel cell applications.

scholarly journals Theoretical Investigation of the Deactivation of Ni Supported Catalysts for the Catalytic Deoxygenation of Palm Oil for Green Diesel Production

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 747
Author(s):  
Sanaa Hafeez ◽  
Sultan M Al-Salem ◽  
Kyriakos N Papageridis ◽  
Nikolaos D Charisiou ◽  
Maria A Goula ◽  
...  
Keyword(s):  
Palm Oil ◽  
Catalyst Deactivation ◽  
Supported Catalysts ◽  
Fluid Dynamic ◽  
Catalyst Activity ◽  
Cfd Model ◽  
Green Diesel ◽  
Zro2 Catalyst ◽  
Catalytic Deoxygenation ◽  
First Time

For the first time, a fully comprehensive heterogeneous computational fluid dynamic (CFD) model has been developed to predict the selective catalytic deoxygenation of palm oil to produce green diesel over an Ni/ZrO2 catalyst. The modelling results were compared to experimental data, and a very good validation was obtained. It was found that for the Ni/ZrO2 catalyst, the paraffin conversion increased with temperature, reaching a maximum value (>95%) at 300 °C. However, temperatures greater than 300 °C resulted in a loss of conversion due to the fact of catalyst deactivation. In addition, at longer times, the model predicted that the catalyst activity would decline faster at temperatures higher than 250 °C. The CFD model was able to predict this deactivation by relating the catalytic activity with the reaction temperature.

Computational Fluid Dynamics Modelling of Photoelectrocatalytic Reactors for the Degradation of Formic Acid

2016 ◽  
Vol 835 ◽  
pp. 386-393 ◽  
Author(s):  
Yi Wen Phuan ◽  
Eileen Ai Lyn Lau ◽  
Harun Mohamed Ismail ◽  
Byeong Kyu Lee ◽  
Meng Nan Chong
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Formic Acid ◽  
Experimental Work ◽  
Cfd Simulation ◽  
Cfd Model ◽  
Cfd Modelling ◽  
Organic Degradation ◽  
Chemical Reaction Kinetics ◽  
Acid Degradation

In this study, computational fluid dynamics (CFD) simulation was used to predict the performance of photoelectrocatalytic (PEC) reactors with surface reactions. PEC process is a promising and sustainable method that is capable for simultaneous organic degradation and hydrogen production. However, the overall PEC process efficiency is still unsatisfactory and not ready for scale-up application. Preliminary study using CFD model can help to reduce development time, money and effort in experimental work while providing comprehensive analysis and optimum PEC reactor design prior to its real physical fabrication. CFD model integrates irradiance distribution, hydrodynamics, species mass transport and chemical reaction kinetics within the reactor. The performance of PEC reactor for organic degradation depends on reactor configurations and hydrodynamic conditions. Thus, the main aim of this study was to optimize different PEC reactor designs using CFD modelling by varying the reactor configurations and hydrodynamic flow conditions for improved efficiency in degrading the sample organic pollutant of formic acid. The CFD modelling showed higher formic acid degradation efficiency for the simulated convex surface photoreactor than the flat surface photoreactor due to the former possess the ability to concentrate the absorbed light onto the photoanode surface. Besides, the CFD modelling showed that the formic acid degradation rate increased with decreasing inlet fluid flow velocity. This was due to the uniform flow distribution that enables evenly coverage of photoanode surface for subsequent degradation of formic acid in the PEC reactors. Further experimental work is required to validate the CFD simulation to allow better understanding and improvement of the overall efficiency of PEC reactors.

Modelling Study of Palladium Membrane Reactor Performance during Methan Steam Reforming using CFD Method

2016 ◽  
Vol 11 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Kamran Ghasemzadeh ◽  
Ehsan Andalib ◽  
Angelo Basile
Keyword(s):  
Experimental Data ◽  
Steam Reforming ◽  
Methane Conversion ◽  
Membrane Reactor ◽  
Fluid Dynamic ◽  
Molar Fraction ◽  
Methane Steam Reforming ◽  
Cfd Model ◽  
Palladium Membrane ◽  
Hydrogen Recovery

Abstract The main aim of this study is the investigation of dense palladium membrane reactor (MR) performance during methane steam reforming (MSR) reaction using computational fluid dynamic (CFD). To this purpose, a two-dimensional isothermal CFD model was developed and its validation was realized by comparing the theoretical results with our experimental data achieved in ITM of Italy. In this work, the CFD model was presented by COMSOL- Multiphysics software version 5. The reaction rate expressions and kinetics parameters were used from literatures. According to validation results, a good agreement between modeling results and experimental data was found. After model validation, the effect of the some important operating parameters (temperature and pressure) on the performance of palladium MR was studied in terms of methane conversion and hydrogen recovery. The CFD model presented velocity and pressure profiles in both side of MR and also molar fraction of different species in permeate and retentate streams. The modeling results showed that the palladium MR presents comparable performance with respect to traditional reactor (TR) in terms of the methane conversion, especially, at lower temperatures and higher pressures. In fact, CFD results indicated that palladium MR performance was improved by increasing the reaction pressure, while this parameter had negative effect on the TR performance. This result related to increasing the hydrogen permeance through the palladium membrane by enhancement of pressure gradient. Indeed, this shift effect can provide a higher methane conversion in lower temperatures in the palladium MR. In particular, 99% methane conversion and 43% hydrogen recovery was achieved at 500°C and 1.5 atm.

Hydrogenation of Acetylene: Kinetic Studies and Reactor Modeling

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
Navid Mostoufi ◽  
Ali Ghoorchian ◽  
Rahmat Sotudeh-Gharebagh
Keyword(s):  
Experimental Data ◽  
Catalyst Deactivation ◽  
Fixed Bed ◽  
Kinetic Studies ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Reactor Modeling ◽  
Deactivation Rate Constant ◽  
Hydrogenation Reactor ◽  
Kinetics Of

The kinetics of acetylene hydrogenation has been studied in a fixed bed reactor of a commercial Pd/Al2O3 catalyst. The experiments were carried out at 30, 50 and 70 ºC with various feed compositions at atmospheric pressure. The experiments were repeated at 70 ºC in the presence of the used catalyst to determine the effect of the catalyst deactivation where the corresponding deactivation rate constant was determined in order to predict the activity of the catalyst during each run. Two well known kinetic models were used for a nearly similar catalyst to predict the experimental data of this work and none of them were found satisfactory. A new model was then proposed to fit the experimental data. The hydrogenation reactor was also simulated at industrial operating conditions with the proposed kinetics for both plug and dispersion flows. The results of these simulations were almost close to each other in most cases.

Integration of coliform decay within a CFD (computational fluid dynamic) model of a waste stabilisation pond

2003 ◽  
Vol 48 (2) ◽  
pp. 205-210 ◽  
Author(s):  
A. Shilton ◽  
J. Harrison
Keyword(s):  
Flow Reactor ◽  
Fluid Dynamic ◽  
Reaction Model ◽  
Cfd Model ◽  
Treatment Efficiency ◽  
Cfd Modelling ◽  
Ideal Flow ◽  
Standard Design ◽  
Order Of Magnitude ◽  
Predicted Values

CFD mathematical modelling offers the potential to predict the actual flow pattern in a pond rather than generalising its mixing and mass transport as either an ideal flow reactor or, in the case of the non-ideal flow reactor, as a single dispersion number. However, perhaps the greatest benefit that CFD offers over the previous approaches is its ability to directly account for physical influences on the pond hydraulics such as the addition of baffles for example. In addition to solving the equations of fluid flow, CFD modelling also allows incorporation of other equations. The next logical development is, therefore, the integration of a reaction model within its solution domain. This potential has been recognised by several researchers, but to date no such work has been published. The primary aim of this paper was to present a CFD model of a field pond that incorporates the first order decay equation for coliforms. Experimental monitoring of the field pond gave an average effluent concentration of 3,710 f.c./100 mL, while the CFD model predicted 4,600 f.c./100 mL. Considering the pond provides an order of magnitude decrease in faecal coliform concentration, the integrated CFD model has clearly predicted the treatment efficiency very well. The secondary aim of this paper was to demonstrate the potential application of this technique. A typical pond was designed and modelled along with two variations incorporating two baffles and six baffles respectively. As is typically found in pond systems, the standard design suffered from severe short-circuiting with the model predicting a value of 6.2 × 106 f.c./100 mL at the outlet. The simulations of the baffled designs illustrate how treatment efficiency was improved by reducing the short-circuiting through the pond. The model predicted values of 6.0 × 103 f.c./100 mL for the 2-baffle design and 5.7 × 102 f.c./100 mL for the 6-baffle design.

scholarly journals Preliminary CFD Assessment of an Experimental Test Facility Operating with Heavy Liquid Metals

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Matteo Lizzoli ◽  
Walter Borreani ◽  
Francesco Devia ◽  
Guglielmo Lomonaco ◽  
Mariano Tarantino
Keyword(s):  
Experimental Data ◽  
Liquid Metals ◽  
Fluid Dynamic ◽  
Operating Conditions ◽  
Test Facility ◽  
Cfd Analysis ◽  
Cfd Model ◽  
Cfd Simulations ◽  
Pressure Drops ◽  
Venturi Nozzle

The CFD analysis of a Venturi nozzle operating in LBE (key component of the CIRCE facility, owned by ENEA) is presented in this paper. CIRCE is a facility developed to investigate in detail the fluid-dynamic behavior of ADS and/or LFR reactor plants. The initial CFD simulations have been developed hand in hand with the comparison with experimental data: the test results were used to confirm the reliability of the CFD model, which, in turn, was used to improve the interpretation of the experimental data. The Venturi nozzle is modeled with a 3D CFD code (STAR-CCM+). Later on, the CFD model has been used to assess the performance of the component in conditions different from the ones tested in CIRCE: the performance of the Venturi is presented, in terms of pressure drops, for various operating conditions. Finally, the CFD analysis has been focused on the evaluation of the effects of the injection of an inert gas in the flow of the liquid coolant on the performance of the Venturi nozzle.

Development of a Kinetic Model for Modeling the Industrial VGO Hydrocracker Accompanied By Deactivation

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Azita Barkhordari ◽  
Shohreh Fatemi ◽  
Mahdi Daneshpayeh ◽  
Hossain Zamani
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Catalyst Deactivation ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Wide Range ◽  
Silica Alumina ◽  
Parallel Reactions

Two types of kinetic modeling, continuous and discrete lump model were studied and compared in this research in order to model the industrial scale VGO hydrocracking process. The experimental data obtained from a pilot-scale fixed bed reactor over Ni-Mo/Silica-Alumina catalyst in a wide range of operating conditions was used for prediction and tuning the kinetic parameters using Genetic algorithm. In this study, the discrete lump model with four parallel reactions to four lumped products showed more convergence to the experimental data than the continuous lump model. Afterward, the discrete kinetic model was used to simulate the vacuum gas oil (VGO) industrial hydrocracking reaction accompanied by catalyst deactivation. The activity of the catalyst was taken as a time dependent variable and the first year of operational data were used to derive the deactivation parameter. The refinery test runs spanning over the last two and half years of operation were used to validate the model and interpret the simulation results. A comparison between the industrial and the predicted data showed that there is a good agreement between them and the presented model provides a reasonable fit to estimate the product yields of LPG, naphtha, kerosene, diesel.

Effects of Over Fire Air on the Combustion and NOx Emission Characteristics of a 600 MW Opposed Swirling Fired Boiler

2012 ◽  
Vol 512-515 ◽  
pp. 2135-2142 ◽  
Author(s):  
Yu Peng Wu ◽  
Zhi Yong Wen ◽  
Yue Liang Shen ◽  
Qing Yan Fang ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Empirical Method ◽  
Nox Emission ◽  
Emission Characteristics ◽  
Cfd Model ◽  
Nitrogen Release ◽  
Computational Fluid Dynamics Cfd ◽  
Low Nox Emission

A computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established. The chemical percolation devolatilization (CPD) model, instead of an empirical method, has been adapted to predict the nitrogen release during the devolatilization. The current CFD model has been validated by comparing the simulated results with the experimental data obtained from the boiler for case study. The validated CFD model is then applied to study the effects of ratio of over fire air (OFA) on the combustion and nitrogen oxides (NOx) emission characteristics. It is found that, with increasing the ratio of OFA, the carbon content in fly ash increases linearly, and the NOx emission reduces largely. The OFA ratio of 30% is optimal for both high burnout of pulverized coal and low NOx emission. The present study provides helpful information for understanding and optimizing the combustion of the studied boiler

Biochar caged zirconium ferrite nanocomposites for the adsorptive removal of Reactive Blue 19 dye in a batch and column reactors and conditions optimizaton

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shazia Perveen ◽  
Raziya Nadeem ◽  
Shaukat Ali ◽  
Yasir Jamil
Keyword(s):  
Experimental Data ◽  
Low Dose ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Adsorption Efficiency ◽  
Fixed Bed Column ◽  
Flow Rates ◽  
Adsorptive Removal ◽  
Reactive Blue 19 ◽  
Pseudo Second Order

Abstract Biochar caged zirconium ferrite (BC-ZrFe2O5) nanocomposites were fabricated and their adsorption capacity for Reactive Blue 19 (RB19) dye was evaluated in a fixed-bed column and batch sorption mode. The adsorption of dye onto BC-ZrFe2O5 NCs followed pseudo-second-order kinetics (R 2 = 0.998) and among isotherms, the experimental data was best fitted to Sips model as compared to Freundlich and Langmuir isotherms models. The influence of flow-rate (3–5 mL min−1), inlet RB19 dye concentration (20–100 mg L−1) and quantity of BC-ZrFe2O5 NCs (0.5–1.5 g) on fixed-bed sorption was elucidated by Box-Behnken experimental design. The saturation times (C t /C o  = 0.95) and breakthrough (C t /C o  = 0.05) were higher at lower flow-rates and higher dose of BC-ZrFe2O5 NCs. The saturation times decreased, but breakthrough was increased with the initial RB19 dye concentration. The treated volume was higher at low sorbent dose and influent concentration. Fractional bed utilization (FBU) increased with RB19 dye concentration and flow rates at low dose of BC-ZrFe2O5 NCs. Yan model was fitted best to breakthrough curves data as compared to Bohart-Adams and Thomas models. Results revealed that BC-ZrFe2O5 nanocomposite has promising adsorption efficiency and could be used for the adsorption of dyes from textile effluents.

scholarly journals Measurement of flow velocity profiles in tank structures using the prototype device OCM Pro LR

2011 ◽  
Vol 64 (1) ◽  
pp. 263-270 ◽  
Author(s):  
K. Klepiszewski ◽  
M. Teufel ◽  
S. Seiffert ◽  
E. Henry
Keyword(s):  
Flow Velocity ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Waste Water Treatment ◽  
Transport Processes ◽  
Treatment Efficiency ◽  
Cleaning Efficiency ◽  
Cfd Modelling ◽  
Ultrasonic Signals ◽  
Cfd Models

Generally, studies investigating the treatment efficiency of tank structures for storm water or waste water treatment observe pollutant flows in connection with conditions of hydraulic loading. Further investigations evaluate internal processes in tank structures using computational fluid dynamic (CFD) modelling or lab scale tests. As flow paths inside of tank structures have a considerable influence on the treatment efficiency, flow velocity profile (FVP) measurements can provide a possibility to calibrate CFD models and contribute to a better understanding of pollutant transport processes in these structures. This study focuses on tests carried out with the prototype FVP measurement device OCM Pro LR by NIVUS in a sedimentation tank with combined sewer overflow (CSO) situated in Petange, Luxembourg. The OCM Pro LR measurement system analyses the echo of ultrasonic signals of different flow depths to get a detailed FVP. A comparison of flow velocity measured by OCM Pro LR with a vane measurement showed good conformity. The FVPs measured by OCM Pro LR point out shortcut flows within the tank structure during CSO events, which could cause a reduction of the cleaning efficiency of the structure. The results prove the applicability of FVP measurements in large-scale structures.

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