Development and CFD analysis for determining the optimal operating conditions of 250 kg/day hydrogen generation for an on-site hydrogen refueling station (HRS) using steam methane reforming

Author(s):  
Iman Rahimipetroudi ◽  
Jae Seon Shin ◽  
Kashif Rashid ◽  
Je Bok Yang ◽  
Sang Keun Dong
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

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.


2020 ◽  
pp. 136-136
Author(s):  
Dmitry Pashchenko ◽  
Maria Gnutikova

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.


Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 399
Author(s):  
Rahman ◽  
Ahmad ◽  
Kano ◽  
Mustafa

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.


Author(s):  
Francisco Elizalde-Blancas ◽  
Suryanarayana R. Pakalapati ◽  
Jose A. Escobar-Vargas ◽  
Ismail B. Celik

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.


Author(s):  
Mohsen Behnam ◽  
Anthony G. Dixon

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.


2021 ◽  
Vol 11 (13) ◽  
pp. 6021
Author(s):  
Shinje Lee ◽  
Hyun Seung Kim ◽  
Junhyung Park ◽  
Boo Min Kang ◽  
Churl-Hee Cho ◽  
...  

Steam methane reforming (SMR) process is regarded as a viable option to satisfy the growing demand for hydrogen, mainly because of its capability for the mass production of hydrogen and the maturity of the technology. In this study, an economically optimal process configuration of SMR is proposed by investigating six scenarios with different design and operating conditions, including CO2 emission permits and CO2 capture and sale. Of the six scenarios, the process configuration involving CO2 capture and sale is the most economical, with an H2 production cost of $1.80/kg-H2. A wide range of economic analyses is performed to identify the tradeoffs and cost drivers of the SMR process in the economically optimal scenario. Depending on the CO2 selling price and the CO2 capture cost, the economic feasibility of the SMR-based H2 production process can be further improved.


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