An Improved Design of Microchannel Fuel Processors

2005 ◽  
Author(s):  
Hye-Mi Jung ◽  
Sung-Dae Yim ◽  
Sukkee Um ◽  
Young-Gi Yoon ◽  
Gu-Gon Park ◽  
...  
Keyword(s):  
Numerical Model ◽  
Steam Reforming ◽  
Kinetic Equations ◽  
Methanol Conversion ◽  
Steel Plates ◽  
Catalyst Loading ◽  
Contact Method ◽  
Micro Channel ◽  
Catalytic Combustor ◽  
Improved Design

This paper focuses on a new systematic configuration of micro-channel fuel processors, particularly designed for portable applications. An alternative integration method of the micro-channel fuel processors is attempted to overcome the serious thermal unbalance and to minimize the system volume by introducing the direct contact method of the sub-components. An integrated micro-channel methanol processor was developed by assembling unit reactors, which were fabricated by stacking and bounding micro-channel patterned stainless steel plates, including fuel vaporizer, catalytic combustor and steam reformer. Commercially available Cu/ZnO/Al2O3 catalyst (ICI Synetix 33-5) was coated inside micro-channel of the unit reactor for steam reforming. The steam reforming reaction was conducted in the temperature range of 200°C to 260°C in the basis of reformer side end-plate and the temperature was controlled by varying methanol feeding into the combustor. More than 99% of methanol was converted at 240°C of reformer side temperature. A mechanism-based numerical model aimed at enhancing physical understanding and optimizing designs has been developed for improved micro-channel fuel processors. A two-dimensional numerical model in the reformer section created to model the phenomena of species transport and reaction occurring at the catalyst surface. The mass, momentum, and species equations were employed with kinetic equations that describe the chemical reaction characteristics to solve flow-field, methanol conversion rate, and species concentration variations along the micro-channel. This mechanism-based model was validated against the experimental data from the literature and then applied to various layouts of the micro-channel fuel processors targeted for the optimal catalyst loading and fuel reforming purpose. The computer-aided models developed in this study can be greatly utilized for the design of advanced fast-paced micro-channel fuel processors research.

Preparation of Cu/ZnO for Fabrication of a Micro Methanol Reformer

2007 ◽  
Vol 119 ◽  
pp. 235-238
Author(s):  
Hong Seock Cha ◽  
Tae Gyu Kim ◽  
Se Jin Kwon
Keyword(s):  
Steam Reforming ◽  
Methanol Conversion ◽  
Catalyst Loading ◽  
Fabrication Method ◽  
Micro Structure ◽  
Micro Fabrication ◽  
Steam Reformer ◽  
Steam Reforming Of Methanol ◽  
Strong Adhesion ◽  
Micro Reactor

Three synthesis procedures of Cu/ZnO catalyst for steam reforming of methanol were tested for loading in a micro reactor. The best procedure that resulted in the strong adhesion to the wafer was determined out of the tested procedures. The molecular structure of the synthesized catalyst was examined by XRD and its performance in methanol conversion was measured. A micro fabrication method that incorporates the catalyst loading and micro structure processing was developed. A MEMS methanol steam reformer was built by this process and the completed device resulted in methanol conversion of 93%.

scholarly journals A Multi-Function Compact Micro-Channel Reactor Coated with Sulphur Tolerant Catalyst for LPG Steam Reforming

Fuel Cells ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 516-522 ◽  
Author(s):  
J. Reed ◽  
R. Chen ◽  
C. Dudfield ◽  
P. Adcock
Keyword(s):  
Steam Reforming ◽  
Micro Channel ◽  
Channel Reactor

Study on a Vapor-Feed Air-Breathing Direct Methanol Fuel Cell Assisted by a Catalytic Combustor

2015 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Yuan ◽  
Hong-Rong Xia ◽  
Jin-Yi Hu ◽  
Zhao-Chun Zhang ◽  
Yong Tang
Keyword(s):  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Cell Performance ◽  
Catalyst Loading ◽  
High Concentration ◽  
Methanol Vapor ◽  
Air Breathing ◽  
Direct Methanol ◽  
Catalytic Combustor ◽  
Methanol Fuel Cell

Feeding vaporized methanol to the direct methanol fuel cell (DMFC) helps reduce the effects of methanol crossover (MCO) and facilitates the use of high-concentration or neat methanol so as to enhance the energy density of the fuel cell system. This paper reports a novel system design coupling a catalytic combustor with a vapor-feed air-breathing DMFC. The combustor functions as an assistant heat provider to help transform the liquid methanol into vapor phase. The feasibility of this method is experimentally validated. Compared with the traditional electric heating mode, the operation based on this catalytic combustor results in a higher cell performance. Results indicate that the values of methanol concentration and methanol vapor chamber (MVC) temperature both have direct effects on the cell performance, which should be well optimized. As for the operation of the catalytic combustor, it is necessary to optimize the number of capillary wicks and also catalyst loading. In order to fast trigger the combustion reaction, an optimal oxygen feed rate (OFR) must be used. The required amount of oxygen to sustain the reaction can be far lower than that for methanol ignition in the starting stage.

Improvements to an Air Bypass System on a Kawasaki M1A-13X Engine

2004 ◽  
Author(s):  
Suresh R. Vilayanur ◽  
John Battaglioli
Keyword(s):  
Flow Analysis ◽  
Effective Area ◽  
Inlet Temperature ◽  
Flow Area ◽  
Detailed Measurement ◽  
Pressure Drops ◽  
Operating Range ◽  
Flow Losses ◽  
Catalytic Combustor ◽  
Improved Design

A new bypass system using an improved design has been fabricated and tested on a Kawasaki M1A-13X gas turbine engine. The engine and catalytic combustor are currently installed at the City of Santa Clara’s Silicon Valley Power municipal electrical generating stations and connected to the utility grid. The use of a bypass system with a catalytic combustor, incorporating the Xonon Cool Combustion™ technology, on an M1A-13X system increases the low emissions load turndown and ambient operating range without impacting engine efficiency. The increased operating range is achieved because the bypass system provides the required adiabatic combustion temperature (Tad) in the combustor’s post-catalyst burn out zone without changing the turbine inlet temperature. A detailed measurement of the pressure drops, in the old bypass system, revealed that there were large flow losses present, particularly in the re-injection spool piece and the extraction plenum. Since it was determined that the spool had the highest pressure loss, this was the component targeted for improvement. The analysis coupled with detailed measurements on the reinjection piece revealed that the effective area actually varied with flow As the flow changed, so did the flow mechanics inside and exiting the spool piece. Therefore, in order to achieve the design target, the flow area of the spool piece had to be optimized at the predicted capacity flow rate. CFD analysis of the spool piece revealed the regions of losses in the re-injection piece. This analysis along with a one-dimensional flow analysis of the entire system enabled the design of new spool re-injection piece. Once the design was completed, the new bypass system was fabricated and tested. Bypass flow capacity was increased by about 22%. This was achieved by alleviating regions of flow losses and also by using a new “scoop” design for the bypass reinjection tubes. As expected, engine turndown capacity and ambient operating range were improved with the new design.

scholarly journals Theoretical and numerical investigation into brush seal hysteresis without pressure differential

2019 ◽  
Vol 28 ◽  
pp. 096369351988538
Author(s):  
Yuchi Kang ◽  
Meihong Liu ◽  
Xiangping Hu ◽  
Sharon Kao-Walter ◽  
Baodi Zhang
Keyword(s):  
Numerical Model ◽  
Reaction Force ◽  
Pressure Differential ◽  
Influential Factor ◽  
Contact Method ◽  
Analytic Model ◽  
The Finite Element Method ◽  
Brush Seal ◽  
Type Contact ◽  
Contact Seal

Brush seal is a novel type contact seal, and it is well-known due to its excellent performance. However, there are many intrinsic drawbacks, such as hysteresis, which need to be solved. This article focused on modeling hysteresis in both numerical way and analytic way without pressure differential. The numerical simulation was solved by the finite element method. General contact method was used to model the inter-bristle contact, bristle–rotor contact, and bristle–backplate contact. Bristle deformation caused by both vertical and axial tip force was used to validate the numerical model together with reaction force. An analytic model in respect of the strain energy was created. The influence of structure parameters on the hysteresis ratio, with the emphasis on the derivation of hysteresis ratio formula for brush seals, was also presented. Both numerical model and analytic model presented that cant angle is the most influential factor. The aim of the article is to provide a useful theoretical and numerical method to analyze and predict the hysteresis. This work contributes the basis for future hysteresis investigation with pressure differential.

Numerical Simulation of Steam Reforming of Methanol in Micro-Channel Reactor

2005 ◽  
Author(s):  
Wenzhi Cui ◽  
Longjian Li ◽  
Tien-Chien Jen ◽  
Qinghua Chen ◽  
Quan Liao
Keyword(s):  
Numerical Simulation ◽  
Steam Reforming ◽  
Hydrogen Generation ◽  
Volume Ratio ◽  
Micro Channel ◽  
Microchannel Reactor ◽  
Fuel Processing ◽  
Reaction Heat ◽  
Steam Reforming Of Methanol ◽  
Hot Air

On-board hydrogen generation from hydrocarbon fuels, such as methanol, natural gas, gasoline and diesel, etc., will be technically feasible in the near future for fuel cell powered vehicles. Among all the fuel processing methods, steam reforming is considered as the most widely used method of hydrogen reforming for the lower reactive temperature, pressure and higher hydrogen ratio in reformate. A laminate micro-channel catalytic reactor was designed for the purpose of hydrogen generation from hydrocarbons. The depth of the reaction channel is 0.5 mm, and the length and width are 50 mm and 40 mm, respectively. The same geometry is designed for the heating channels. A metal sheet is placed between reacting and heating channels to separate them. Piling up alternately the two channels is to buildup the laminate microchannel reactor. Numerical simulation has been conducted in one reactive unit, i.e., one reacting channel and one heating channel. The reactant is the solution of methanol and water mixing with a certain ratio. And the reaction heat is provided by hot air flow with a temperature of 600K. A 2D steady model of the reforming reactive processes was developed and solved numerically. The ratio of water and methanol is set to be at 1.3. The conversion rate of methanol was nearly 100% at the outlet of reactor, while the volume ratio of hydrogen is 51.4% with the selectivity of CO2 reaches 49.2%. Detail results showed that the 50 mm long reacting channel could be divided into four different regimes along with the reacting course. In the first regime (0-5mm), methanol in the reactants is almost completely converted and CO is mainly generated in the third one (15-20mm), while reactions in the other two regimes are indiscoverable. The reasons leading to such phenomena are clarified in this paper.

Simulations of Fully-Flexible Fuel Bundle Response due to Turbulence Excitation

2019 ◽  
Author(s):  
Osama Elbanhawy ◽  
Marwan Hassan ◽  
Atef Mohany
Keyword(s):  
Numerical Model ◽  
Single Point ◽  
Point Contact ◽  
Vibration Response ◽  
Pressure Tube ◽  
Contact Method ◽  
Impact Forces ◽  
Fuel Bundle ◽  
System Components ◽  
Fuel Elements

Abstract This work presents a numerical model for a fully-flexible CANDU fuel bundle to predict the vibration response due to turbulence excitation. The model includes 37 fuel elements and two endplates. The contact between system components such as fuel-to-fuel and fuel-to-pressure tube is modeled using the single point contact method (SPC). A range of flow velocities was examined, and the associated impact forces and work rates were calculated. In addition, the stresses on the endplates due to vibration of the fuel elements were predicted.

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