3D CFD Simulations of Local Carbon Formation in Steam Methane Reforming Catalyst Particles

2017 ◽  
Vol 15 (6) ◽  
Author(s):  
Mohsen Behnam ◽  
Anthony G. Dixon
Keyword(s):  
Hot Spots ◽  
Tube Wall ◽  
Particle Diameter ◽  
Catalyst Particle ◽  
Operating Conditions ◽  
Methane Reforming ◽  
Carbon Formation ◽  
Cfd Simulations ◽  
Steam Methane Reforming ◽  
Steam Methane

Abstract The deactivation of catalysts is an important problem in the strongly endothermic steam methane reforming reaction. The local carbon laydown on the catalyst surface may lead to local hot spots, breakage of catalyst particles, and blockage of the reactor tube. Local carbon formation was studied at different operating conditions using particle-scale 3D CFD models of full and hollow cylindrical particles. The results showed that a low steam-to-carbon ratio may cause local carbon formation at high temperature (\gt900K) on the surface of the catalyst particle. The risk of carbon formation was highest at the surface hot spots and inside the catalyst particles where the methane cracking reaction rate exceeded those of the gasification reactions. The internal surface in the 1-hole catalyst particle showed favorable conditions for carbon formation and deposition, similarly to the external surface of the particle. 3D CFD simulations of a 0.76 m length of a full tube of spherical catalyst particles with tube-to-particle diameter ratio 5.96 showed that the rate of carbon formation was much higher next to the heated tube wall and decreased significantly from the tube wall to the tube center.

scholarly journals Thermodynamic analysis of carbon formation conditions in a steam methane reforming process

2020 ◽  
pp. 136-136
Author(s):  
Dmitry Pashchenko ◽  
Maria Gnutikova
Keyword(s):  
Thermodynamic Analysis ◽  
Chemical Reactions ◽  
Operating Conditions ◽  
Mass Action ◽  
Equilibrium Analysis ◽  
Methane Reforming ◽  
Carbon Formation ◽  
Operational Conditions ◽  
Steam Methane Reforming ◽  
Steam Methane

Thermodynamic equilibrium analysis of the steam methane reforming process to synthesis gas was studied. For this purpose, the system of chemical reactions for carbon production and consumation as well as other side reaction in the steam methane reforming process were analysed. The material balance and the equations of law mass action were obtained for various chemical reactions. The system of those equations were solved by dichotomy method. The investigation was performed for a wide range of operational conditions such as a temperature, pressure, and inlet steam-to-methane ratio. The results obtained, with the help of developed algorithms, were compared with the results obtained via different commercial and open-source programs. All results are in excellent agreement. The operational conditions for the probable formation of carbon were determined. It was established that for the temperature range above 1100K the probability of carbon formation is absent for steam-to-methane ratio above units. The presented algorithm of thermodynamic analysis gives an appearance of the dependence of the product composition and the amount of required heat from operating conditions such as the temperature, pressure and steam-to-methane ratio.

scholarly journals Carbon Formation and Active Site of Alumina Supported Platinum Catalyst in Steam Methane Reforming Containing Sulfur

2020 ◽  
Vol 63 (2) ◽  
pp. 89-95
Author(s):  
Fumihiro WATANABE ◽  
Ikuko KABURAKI ◽  
Kazumasa OSHIMA ◽  
Naohiro SHIMODA ◽  
Akira IGARASHI ◽  
...  
Keyword(s):  
Active Site ◽  
Platinum Catalyst ◽  
Methane Reforming ◽  
Carbon Formation ◽  
Steam Methane Reforming ◽  
Steam Methane ◽  
Supported Platinum ◽  
Supported Platinum Catalyst

Modeling of a Nickel-based Fluidized Bed Membrane Reactor for Steam Methane Reforming Process

2019 ◽  
Vol 41 (2) ◽  
pp. 219-219
Author(s):  
Mustafa Kamal Pasha Mustafa Kamal Pasha ◽  
Iftikhar Ahmad Iftikhar Ahmad ◽  
Jawad Mustafa Jawad Mustafa ◽  
Manabu Kano Manabu Kano
Keyword(s):  
Fluidized Bed ◽  
Membrane Reactor ◽  
Operating Conditions ◽  
Methane Reforming ◽  
Hydrogen Yield ◽  
Reactor Model ◽  
Membrane Area ◽  
Steam Methane Reforming ◽  
Steam Methane ◽  
Process Simulator

Hydrogen being a green fuel is rapidly gaining importance in the energy sector. Steam methane reforming is one of the most industrially important chemical reaction and a key step in the production of high purity hydrogen. Due to inherent deficiencies of conventional reforming reactors, a new concept based on fluidized bed membrane reactor is getting the focus of researchers. In this work, a nickel-based fluidized bed membrane reactor model is developed in the Aspen PLUSand#174; process simulator. A user-defined membrane module is embedded in the Aspen PLUSand#174; through its interface with Microsoftand#174; Excel. Then, a series combination of Gibbs reactors and membrane modules are used to develop a nickel-based fluidized bed membrane reactor. The model developed for nickel-based fluidized bed membrane reactor is compared with palladium-based membrane reactor in terms of methane conversion and hydrogen yield for a given panel of major operating parameters. The simulation results indicated that the model can accurately predict the behavior of a membrane reactor under different operating conditions. In addition, the model can be used to estimate the effective membrane area required for a given rate of hydrogen production.

scholarly journals Model Development and Exergy Analysis of a Microreactor for the Steam Methane Reforming Process in a CFD Environment

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 399
Author(s):  
Rahman ◽  
Ahmad ◽  
Kano ◽  
Mustafa
Keyword(s):  
Conversion Efficiency ◽  
Exergy Analysis ◽  
Energy Analysis ◽  
Operating Conditions ◽  
Methane Reforming ◽  
Cfd Model ◽  
Field Function ◽  
Efficient Operation ◽  
Steam Methane Reforming ◽  
Steam Methane

Steam methane reforming (SMR) is a dominant technology for hydrogen production. For the highly energy-efficient operation, robust energy analysis is crucial. In particular, exergy analysis has received the attention of researchers due to its advantage over the conventional energy analysis. In this work, an exergy analysis based on the computational fluid dynamics (CFD)-based method was applied to a monolith microreactor of SMR. Initially, a CFD model of SMR was developed using literature data. Then, the design and operating conditions of the microreactor were optimized based on the developed CFD model to achieve higher conversion efficiency and shorter length. Exergy analysis of the optimized microreactor was performed using the custom field function (CFF) integrated with the CFD environment. The optimized catalytic monolith microreactor of SMR achieved higher conversion efficiency at a smaller consumption of energy, catalyst, and material of construction than the reactor reported in the literature. The exergy analysis algorithm helped in evaluating length-wise profiles of all three types of exergy, namely, physical exergy, chemical exergy, and mixing exergy, in the microreactor.

Numerical Evaluation and Comparison of Different Reduced Mechanisms for Predicting the Performance of a SOFC Operating on Coal Syngas

2008 ◽  
Author(s):  
Francisco Elizalde-Blancas ◽  
Suryanarayana R. Pakalapati ◽  
Jose A. Escobar-Vargas ◽  
Ismail B. Celik
Keyword(s):  
A Priori ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Methane Reforming ◽  
Coal Syngas ◽  
Steam Methane Reforming ◽  
Steam Methane ◽  
Catalyzed Reactions ◽  
Shift Reaction ◽  
Water Gas

Three-dimensional numerical simulations of an anode supported button solid oxide fuel cell were performed using the code developed in house DREAM SOFC. The cell operates on coal syngas at atmospheric pressure and 1073 K. A gas phase mechanism and a heterogeneous mechanism are studied in this work to assess their influence on the performance of the button cell. Both mechanisms take into account the steam methane reforming reaction and water gas shift reaction. The implemented electrochemistry model allows the cell to simultaneously electrochemically oxidize H2 and CO. Results show that methane reforming from the bulk reactions is negligible compared to the catalyzed reactions. Also with a higher reformation the power delivered by the cell is improved. A small temperature difference of one degree is observed when both mechanisms are compared. The electrochemistry model does not require the ratio between current produced from H2 and CO to be prescribed a priori as an input. Under the operating conditions used in this study the model predicts the ratio to be around 4 for both mechanisms.

Sign in / Sign up

Export Citation Format

Share Document