Fractal channel design in a micro methanol steam reformer

CATEGORY: STEAM REFORMERS 
Fractal channel design in a micro methanol steam reformer

Type	Journal Article
Author	Yu-Xian Huang
Author	Jiin-Yuh Jang
URL	http://www.sciencedirect.com/science/article/pii/S0360319913028516
Volume	39
Issue	5
Pages	1998-2007
Publication	International Journal of Hydrogen Energy
Date	February 4, 2014
Abstract	Presents results of a study of the fractal channel pattern design and the gradient catalyst layer in relation to their effects on the performance of a micro methanol steam reformer. Researchers designed a three-dimensional simulation model to predict the effects of bio-channel design on the performance of a micro-reformer. They also studied CO concentration in the production gases, which is necessary to avoid the poisoned catalyst layers of low temperature fuel cells. They also predicted the distributions of velocity and gas concentrations, and evaluated the methanol conversion ratios. They propose a gradient catalyst layer arrangement to delay the timing of hydrogen generation and thus avoid the presence of hydrogen in the catalyst layer too long.

Steam reforming plant optimization with Model Predictive Control

CATEGORY: MPC – MODEL PREDICTIVE CONTROL
2013 IEEE 18^th Conference on Emerging Technologies & Factory Automation (ETFA), 10-13 Sept. 2013, Page(s): 1 – 8, Cagliari, Italy
Steam reforming plant optimization with Model Predictive Control
Zanoli, Silvia M. ; Orlietti, Lorenzo
DII - Dipartimento dell'Ingegneria dell'Informazione, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona AN, Italy
Abstract
Describes the optimization of a steam reforming unit located in a petrochemical plant. MPC, or Model Predictive Control , was used to address the need to enhance efficiency, to increase profitability, and to meet precise production standards. Implemented in an actual plant, the performance of the MPC system was compared with the performance obtained with previous PID controllers.
Hydrogen demand in refineries is increasing due to clean-fuels programs. Hydrocarbon steam reforming is currently the main technology used to produce hydrogen. Most reforming plants are controlled with standard PID control loops that assure safety requirements and good performances for single loops.  However, with these conventional methods, designing integrated solutions for controlling systems with interacting variables and constraints is difficult. In many cases the operators run the systems so as to guarantee the safety of the processes, neglecting those aspects related to profitability.
Authors have addressed the need to follow rapidly changing economic factory goals involving many variables and constraints. Their goal is development and implementation of a Model Predictive Control (MPC) for the optimization of a steam reforming plant located in a petroleum refinery plant.
Full Text Source (Subscription or Fee): http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6647993&contentType=Conference+Publications 

In situ synthesis of Ni/MgO catalysts on inorganic paper-like matrix for methane steam reforming

Chemical Engineering Journal, Volume 229, 1 August 2013, Pages 515–521
In situ synthesis of Ni/MgO catalysts on inorganic paper-like matrix for methane steam reforming
Shin Miura (a), Yuuka Umemura (a), Yusuke Shiratori (b), Takuya Kitaoka (a)
a Department of Agro-Environmental Sciences, Graduate School of Bioresource and Bioenvironmental Sciences, and Biotron Application Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
b Department of Mechanical Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
Abstract
Researchers used two distinct methods to study in situ synthesis of nickel/magnesium oxides (Ni/MgO) on a microstructured inorganic paper support to develop high-performance, easily handled, paper-like catalysts. The methods were: (1) sequential impregnation and (2) co-impregnation.
They first fabricated porous paper supports using a conventional papermaking technique. They then simply impregnated the paper with Mg(NO₃)₂ and Ni(NO₃)₂ solutions, either stepwise or at the simultaneously. After reduction in a hydrogen flow, Ni/MgO catalysts were formed in the paper composites. The resulting Ni/MgO paper is much like an ordinary paper product. It is flexible, lightweight, and easy to handle. The Ni/MgO paper composites, especially the co-impregnated paper, showed excellent catalytic performances in the steam reforming of methane. They produced hydrogen much more efficiently than did commercial Ni-based catalysts in powdered and pellet forms. The Ni/MgO paper composites also exhibited good durability for 24 hour continuous reaction, maintaining their initial efficiency for methane steam reforming.
Full Text Source (Subscription or Fee): http://www.sciencedirect.com/science/article/pii/S1385894713008255

2D heat and mass transfer modeling of methane steam reforming for hydrogen production in a compact reformer

Energy Conversion and Management, Volume 65, January 2013, Pages 155–163
Global Conference on Renewable energy and Energy Efficiency for Desert Regions 2011 "GCREEDER 2011"
2D heat and mass transfer modeling of methane steam reforming for hydrogen production in a compact reformer
Meng Ni
Building Energy Research Group, Department of Building and Real Estate, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
Abstract
Author describes a study of compact reformers (CRs), which are promising devices for efficient fuel processing. In CRs, a thin solid plate is sandwiched between two catalyst layers to enable efficient heat transfer from combustion duct to the reforming duct for fuel processing. For this investigation, researchers developed a 2D heat and mass transfer model to examine the fundamental transport phenomenon and chemical reaction kinetics in a CR for hydrogen production by methane steam reforming (MSR).
They considered both MSR reaction and water gas shift reaction (WGSR) model. They conducted parametric simulations to explore the effects of various structural/operating parameters, including pore size, permeability, gas velocity, temperature, and rate of heat supply on the reformer performance. They observed that the reaction rates of MSR and WGSR are the highest at the inlet, while decreasing significantly along the reformer. Increasing the operating temperature raises the reaction rates at the inlet. However, this exhibits very small influence in the downstream. In contrast, increasing the rate of heat supply raises the reaction rates in the downstream due to increased temperature. A high gas velocity and permeability facilitates gas transport in the porous structure, thereby enhancing reaction rates in the downstream of the reformer.
Full Text Source (Subscription or Fee): http://www.sciencedirect.com/science/article/pii/S0196890412003032

Methanol steam reforming for hydrogen generation via conventional and membrane reactors: A review

Renewable and Sustainable Energy Reviews, Volume 29, January 2014, Pages 355–368
Methanol steam reforming for hydrogen generation via conventional and membrane reactors: A review
A. Iulianelli (a), P. Ribeirinha (b), A. Mendes (b), A. Basile (a)
a ITM-CNR, Via P. Bucci Cubo 17/C, University of Calabria, Rende, CS 87036, Italy
b LEPAE-Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, Porto 4200-465, Portugal
Open Access
Abstract
Hydrogen shows great promise as an energy carrier useful for polymer electrolyte membrane fuel cells (PEMFC) supply. However, PEMFCs require high purity hydrogen as a feed. To address this problem, in situ hydrogen generation is a potential solution for both alcohols and hydrocarbons steam reforming reaction.
Because methanol is liquid at ambient conditions, possesses relatively high H/C ratio, low reforming temperature  and is producible from biomass, it is an interesting hydrogen source. There is abundant literature on inorganic membrane reactors utilized for hydrogen generation via methanol steam reforming reaction. Authors review the earlier state of the art from an experimental point of view about hydrogen production from methanol reforming performed in both conventional and membrane reactors. They also offer an overview of methanol reforming catalysts, as well as a discussion on the impact of methanol steam reforming process via inorganic membrane reactors to produce hydrogen for PEMFCs supply.
Free Full Text Source: http://www.sciencedirect.com/science/article/pii/S1364032113005728

Experimental study on the performance of hydrogen production from miniature methanol–steam reformer integrated with Swiss-roll type combustor for PEMFC

CATEGORY: HYDROGEN
Applied Energy, Volume 105, May 2013, Pages 86–98
Experimental study on the performance of hydrogen production from miniature methanol–steam reformer integrated with Swiss-roll type combustor for PEMFC
Rei-Yu Chein (a) , Yen-Cho Chen (b), Che-Ming Chang (a), J.N. Chung (c)
a Department of Mechanical Engineering, National Chung-Hsing University, Taichung City 402, Taiwan
b Department of Energy Engineering, National United University, Miaoli City 360, Taiwan
c Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611-6300, United States
Abstract
Describes design and testing of a miniature plate-type hydrogen production reactor using methanol as fuel. The reactor consists of a catalytic combustor, vaporizer, reformer, and methanator. Researchers fabricated all components on a single piece of rectangular quartz glass plate 50 mm × 44 mm × 7 mm in size.
They fabricated the combustor on one side of the glass plate with a Swiss-roll type channel in which the Pt/Al₂O₃ particles were loaded in segmented form to catalyze the combustion. A spiral channel was fabricated on the other side of the plate and divided into three sections: a vaporizer for liquid methanol–water mixture vaporization, a reformer for methanol–steam reforming catalyzed by CuO/ZnO/Al₂O₃ particles and a methanator for carbon monoxide (CO) removal catalyzed by Ru/Al₂O₃ particles.
Test results revealed that the reactor successfully produced H₂ and had thermal efficiency ranging from 13% to 35%. High methanol conversion can be obtained from either a low feed rate to the reformer or a high feed rate to the combustor. However, both cases also produce high CO concentrations. The CO methanation reaction was used to reduce the CO concentration. Researchers observed that the methanation reaction depends greatly on the reactor temperature with high temperature not being favorable to this reaction. High CO conversion and low H₂ consumption with low methanol conversion result when the reaction temperature is low. Both thermal management for producing suitable temperature and catalyst activity improvement in high reaction temperature for the methanator are required in the integrated reactor design to reduce the CO concentration down to acceptable levels for fuel cell operation.
Full Text Source (Subscription or Fee): http://www.sciencedirect.com/science/article/pii/S0306261912009312

H2 production by low pressure methanol steam reforming in a dense Pd–Ag membrane reactor in co-current flow configuration: Experimental and modeling analysis

CATEGORY: HYDROGEN
International Journal of Hydrogen Energy, Available online 12 July 2013, In Press, Corrected Proof
H2 production by low pressure methanol steam reforming in a dense Pd–Ag membrane reactor in co-current flow configuration: Experimental and modeling analysis
K. Ghasemzadeh (a),  (b),  (c), S. Liguori (c), P. Morrone (c), A. Iulianelli (c), V. Piemonte (d), A.A. Babaluo (a), A. Basile (c)
a Department of Chemical Engineering, Nanostructure Material Research Center, Sahand University of Technology, Tabriz 51335-1996, Iran
b Department of Chemical Engineering, Urmia University of Technology, Urmia 57166-93187, Iran
c Institute on Membrane Technology of the Italian National Research Council (CNR-ITM), Via P. Bucci c/o University of Calabria Cubo 17/C, Rende (CS) 87046, Italy
d University Campus Biomedico of Rome, via Alvaro del Portillo 21, Rome (RM) 00148, Italy
Abstract
Researchers generated a pure or CO_x-free hydrogen stream using a dense Pd-based packed bed membrane reactor (PBMR) during methanol steam reforming (MSR) reaction. They constructed a valid model which can serve as a tool for deeper analyses of the reaction parameters in the PBMR.
They used a dense Pd–Ag membrane reactor (MR) to carry out MSR at differing gas hourly space velocity (GHSV), feed molar ratio and sweep gas factor (SF) and for low reaction pressures (1.5–2.5 bar). They used a traditional packed bed reactor (PBR), operating at the same PBMR condition, for improved analysis. In the PBMR setup, a dense Pd–Ag membrane with a thickness of 50 μm is used and also a commercial Cu/ZnO/Al₂O₃ catalyst was packed in both types of reactor. Researchers obtained methanol conversion equal to 100% in the PBMR at 280 °C, H₂O/CH₃OH = 3/1 and 2.5 bar, while at the same conditions the PBR reached 91% methanol conversion.
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Pseudo heterogeneous modeling of catalytic methane steam reforming process in a fixed bed reactor

CATEGORY: STEAM REFORMING
Journal of Natural Gas Science and Engineering, Volume 11, March 2013, Pages 46–51
Pseudo heterogeneous modeling of catalytic methane steam reforming process in a fixed bed reactor
Parham Sadooghi, Reinhard Rauch
Vienna University of Technology, Vienna, Austria
Abstract
Authors describe a mathematical model designed to simulate synthesis gas production by methane steam reforming process in a fixed bed reactor filled with catalyst particles. Because of the endothermic nature of the reforming reactions, heat is introduced into the reactor by means of electrical heating.  Consequently, the reactor and catalyst particles are exposed to significant axial and radial temperature gradients.
Authors employ a pseudo heterogeneous model to represent diffusion phenomena inside the reactor tube accurately. They combine heat and mass transfer equations with detailed reaction mechanisms and solve for both the flow phase and within the catalyst pellets. Results provide temperature and concentration distribution along the reactor axial and radial coordinates. They observe strong radial temperature gradients particularly close to the entrance of the reactor.
Full Text Source (Subscription or Fee): http://www.sciencedirect.com/science/article/pii/S1875510012001291