CFD Modeling of Methane Autothermal Reforming in a Catalytic Microreactor

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Ali Fazeli ◽  
Mohsen Behnam
Keyword(s):  
Fuel Cell ◽  
Hydrogen Production ◽  
Hot Spot ◽  
Three Dimensional ◽  
Reaction Rates ◽  
Autothermal Reforming ◽  
Cfd Modeling ◽  
Air Distribution ◽  
Total Oxidation ◽  
High Hydrogen

Producing hydrogen from natural gas for a mini scale fuel cell is a new challenge for researchers. Therefore, modeling of hydrogen production microreactors should be helpful for designing and developing new microreactors. Experimental sensing of velocity, concentration, temperature and reaction rates in numerous points of the microreactor is impracticable. A microreactor in special geometry was considered for hydrogen production and a CFD model was developed in order to incorporate the mechanism of autothermal reforming. This mechanism includes three main reactions and Langmuir-Hinshelwood type kinetic rates. A three dimensional reformer model was developed to simulate the reactive laminar flow model of this microreactor. Effects of styles of feed entrance, air to fuel ratio and adding water to methane were studied. This model shows that there are hot spots near the entrance of the microreactor where the total oxidation of methane occurs and air distribution along the microreactor is a good solution for hot spot problems. The model shows that air distribution is good for fuel cell application because of high hydrogen production and low CO content in the outlet.

Thermodynamic study of hydrogen production from crude glycerol autothermal reforming for fuel cell applications

2010 ◽  
Vol 35 (13) ◽  
pp. 6617-6623 ◽  
Author(s):  
Suthida Authayanun ◽  
Amornchai Arpornwichanop ◽  
Woranee Paengjuntuek ◽  
Suttichai Assabumrungrat
Keyword(s):  
Fuel Cell ◽  
Hydrogen Production ◽  
Crude Glycerol ◽  
Autothermal Reforming ◽  
Thermodynamic Study

Numerical Simulation of an Axisymmetric Ethanol Reforming Reactor for Hydrogen Fuel Cell Applications

2006 ◽  
Author(s):  
Gregory A. Buck ◽  
Hiroyuki Obara
Keyword(s):  
Fuel Cell ◽  
Hydrogen Production ◽  
Autothermal Reforming ◽  
Great Promise ◽  
Hydrogen Fuel Cell ◽  
Hydrogen Fuel ◽  
Gaseous State ◽  
Ethanol Reforming ◽  
Wide Range ◽  
Production Of Hydrogen

Hydrogen fuel cell technology is currently capable of providing adequate power for a wide range of stationary and mobile applications. Nonetheless, the sustainability of this technology rests upon the production of hydrogen from renewable resources. Among the techniques under current study, the chemical reforming of alcohols and other bio-hydrocarbon fuels, appears to offer great promise. In the so called autothermal reforming process, a suitable combination of total and partial oxidation supports hydrogen production from ethanol with no external addition of energy required. Furthermore, the autothermal reforming process conducted in a well insulated reactor, produces temperatures that promote additional hydrogen production through the endothermic steam reforming and the water-gas shift reactions, which may be catalyzed or uncatalyzed, with the added benefit of lowered carbon monoxide concentrations. In this study, an adiabatic ethanol reforming reactor was simulated assuming the reactants to be air (21% O2 and 79% N2) and ethanol (C2H5OH) and the products to be H2O, CO2, CO and H2, with all constituents taken to be in the gaseous state. The air was introduced uniformly through a ring around the side of the reactor and the gaseous ethanol was injected into the center of one end, with products withdrawn from the center of the opposite end, to create an axisymmetric flow field. The gas flows within the reactor were assumed to be turbulent, and the chemical kinetics of a simple four reaction system was assumed to be controlled by turbulent mixing processes. Air and fuel flow rates into the reactor were varied to obtain six different levels of oxidation (air-fuel ratios) while maintaining the same total gaseous mass flow out of the reactor. The numerical results for the reacting flow show that hydrogen production is maximized when the air-fuel ratio on a mass basis is held at approximately 2.8. These findings are in qualitative agreement with observations from previous experimental studies.

Thermodynamic Analysis of the Absorption Enhanced Autothermal Reforming of Ethanol

2013 ◽  
Vol 16 (3) ◽  
pp. 229-237 ◽  
Author(s):  
Virginia Collins-Martínez ◽  
Miguel A. Escobedo Bretado ◽  
Jesús Salinas Gutiérrez ◽  
Miguel Meléndez Zaragoza ◽  
Vanessa. G. Guzmán ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Hydrogen Concentration ◽  
Autothermal Reforming ◽  
Operating Conditions ◽  
Co2 Absorption ◽  
Carbon Formation ◽  
High Hydrogen ◽  
Molar Ratios ◽  
Co2 Absorbent

Thermodynamic analysis of the absorption enhanced autothermal reforming of ethanol using CaO as CO2 absorbent and O2 in the feed was performed to determine favorable operating conditions to produce a high hydrogen ratio (HR, mols H2-produced/EtOH-feed) and hydrogen concentration in gas product. Steam/Ethanol (S/EtOH) and oxygen/ethanol (O2/EtOH) feed molar ratios were varied in order to find autothermal (?H ? 0) and carbon free operating conditions at 300-900°C and CaO as CO2 absorbent at 1 atm. Carbon formation analysis used S/EtOH = 1.75-2.8, while for hydrogen production varied from stoichiometric; 3:1 to 6.5:1, and O2/ETOH from 0 to 1.0. Results indicate no carbon formation at S/EtOH ? stoichiometric. The absorption enhanced autothermal reforming of ethanol using CaO, O2/EtOH = 0.33, S/EtOH = 6.5 and 600°C, produced an autothermal system with 98% H2 and only a reduction of 9.8% in HR and with respect to the CO2 absorption reforming without O2 feed.

Three-dimensional CFD modeling of a direct formic acid fuel cell

2019 ◽  
Vol 44 (58) ◽  
pp. 30627-30635 ◽  
Author(s):  
Nur Hidayah Maslan ◽  
Masli Irwan Rosli ◽  
Mohd Shahbudin Masdar
Keyword(s):  
Fuel Cell ◽  
Formic Acid ◽  
Three Dimensional ◽  
Cfd Modeling

Hydrogen production by autothermal reforming of LPG for PEM fuel cell applications

2008 ◽  
Vol 33 (4) ◽  
pp. 1383-1391 ◽  
Author(s):  
Feyza Gökaliler ◽  
Burcu Selen Çağlayan ◽  
Z. İlsen Önsan ◽  
A. Erhan Aksoylu
Keyword(s):  
Fuel Cell ◽  
Hydrogen Production ◽  
Pem Fuel Cell ◽  
Autothermal Reforming

Autothermal Reforming of Ethanol for Hydrogen Production: Steady State Modeling

2013 ◽  
Vol 415 ◽  
pp. 651-657 ◽  
Author(s):  
Chananchai Wutthithanyawat ◽  
Nawadee Srisiriwat
Keyword(s):  
Steady State ◽  
Fuel Cell ◽  
Hydrogen Production ◽  
Autothermal Reforming ◽  
Adiabatic Temperature ◽  
Efficient Production ◽  
Operating Condition ◽  
Molar Ratios ◽  
Fuel Cell Application ◽  
Production Of Hydrogen

As increasing hydrogen demand for fuel cell application is expected in the near future, the efficient production of hydrogen is vital enabling technology for commercialization of fuel cell for residences and automobiles. Among different technologies of hydrogen production, autothermal reforming is considered to be thermally self-sustaining that the external heat source is not required. In this work, a steady state modeling of autothermal reforming of ethanol for hydrogen production has been performed. Because the operating condition at adiabatic temperature is designed for autothermal reformer, the estimated function of adiabatic temperature as function of steam-to-carbon (S:C) and air-to-carbon (A:C) molar ratios can be determined. At autothermal condition, the effect of S:C and A:C ratios on the product distributions of hydrogen rich stream is thermodynamically investigated. At fixed reactor pressure of 1 bar and preheat temperature of 200 °C, the favorable operating condition for the autothermal reforming of ethanol is found to be a S:C ratio of 2.0 and an A:C ratio of 1.75 at adiabatic temperature of 639 °C.

Sign in / Sign up

Export Citation Format

Share Document