Research Projects

Hydrogen Production Studies

Since hydrogen must be generated by another energy source, hydrogen should be classified as an energy carrier rather than as a natural resource. Pathways of hydrogen production become paramount as utilization of hydrogen increases.

Hydrogen Production For Fuel Cells Via Reforming Coal-Based Methanol

A 36-month investigation of producing hydrogen from coal-based methanol is taking place.  The study will experimentally investigate production of hydrogen from coal-based methanol utilizing the latest reforming technologies for use in a Polymer  Electrolyte (PEM) fuel cell. In addition to demonstrating hydrogen production from a coal derived fuel this study plans to test the resulting product gas, if of sufficient quality , in an existing PEM fuel cell stack and compare the performance utilizing hydrogen fuel that is currently being used in prototype fuel cell vehicles.

This project is funded by DOE Grant Number DE-PS26-02NT41613-06

 This project uses the Steam-reforming and Autothermal-reforming facilities.

Team Members: Hyung Chul Yoon, Chang-hsien Liao

Heat Transfer Limitations in Hydrogen Production via Steam Reformation

Hydrogen can be produced in a variety of methods including steam-reformation of hydrocarbon fuels. In past studies the quasi non-dimensional space velocity parameter (inverse residence time) has been shown to be insufficient in accurately predicting fuel conversion in hydrocarbon-steam reformation. Heat transfer limitations have been manifest with reactors of different geometries. In order to achieve ideal fuel conversion, the heat transfer limitations and the changes of these limitations with respect to geometry must be considered in the reactor design. In this investigation, axial and radial temperature profiles are presented from reactors of different aspect ratios while holding space velocity constant.  Using both the temperature profile information as well as the traditional space velocity limitations one may be able to develop an optimal reactor design.

This project uses the Steam-reforming facility.

Team Members: David Vernon

The Effect of passive Mixing in Steam-reformation

For a cylindrical steam-reforming reactor, large thermal gradients between the heat source (reactor wall) and reactor centerline create a non-ideal condition for complete conversion. This gradient is caused by insufficient heat transfer inside the catalyst bed.  Passive flow disturbance inside catalyst bed provides a potential to enhance the heat and mass transfer in the steam reforming process. This paper presents experimental research that investigates the effect of changing the flow pathway inside the reactor to improve the heat and mass transfer and thus enhance fuel conversion.  The results of this study contribute to the improvement of reformer design for better fuel processing system performance.

This project uses the Steam-reforming facility.

Team Members: Chang-hsien Liao

Acoustic Wave Enhancement in Autothermal-reformation

 This research will investigate the effects of super-positioning  an acoustic field on a methanol autothermal reformation reactor in order to improve the methanol to hydrogen conversion process.

The effectiveness of this method will be measured by comparing the energy output (Lower Heating Value of hydrogen produced) with the total energy input (including energy needed for the acoustic field production).

Team Members: Andreas Lueschen

Comparison of Steam Reforming and Autothermal Reforming of Methanol for Fuel Cell Systems

This proposed study investigates two different reforming methods; autothermal and steam reforming of methanol for fuel cell systems. Generally, the efficiency of overall fuel cell system can be improved by utilizing thermal waste energy from integrated fuel cell system components. This waste energy typically originates from retentate gas from membrane hydrogen separation units and/or flue gas from anode of the fuel cell. Theoretically, steam reforming fuel cell systems have higher thermal efficiencies than autothermal reforming fuel cell systems due to the resultant high concentration of hydrogen.

Therefore, steam reforming is generally recognized as the more suitable fuel processor for fuel cell applications. However, steam reforming can be adversely affected by mass and heat transfer limitations and degradation. Heat exchanger efficiency of steam reformers has been found in experimental units to be less than 50%.  As compared to a steam reformer, an autothermal reformer has internal heat generation which allows for lessened radial temperature gradients due to internal heat generation and higher resultant heat exchange.

Impure methanol streams as found in practice have minute quantities of higher order hydrocarbons which can result in significant catalyst degradations.  Due to increased temperature an autothermal method can reform the small quantities of higher order hydrocarbons and thus increase the effective catalyst lifetime.  It is presently unknown if these theoretical and practical benefits of autothermal reformation can balance the entropy increase associated with higher temperature reformation. 

This project uses the Steam-reforming and Autothermal-reforming facilities.

Links: Related definitions; industry

Team Members: Hyung Chul Yoon, Chang-hsien Liao

Alternative Fuel (E85) to produce Hydrogen via Steam Reformation and Autothermal-reformation

This research is analyzing a hydrogen pathway which would leverage growth in ethanol and bio-alcohols. Bio-ethanol is of particular interest in this regard as it contains a high percentage of hydrogen by weight and volume. Traditionally produced by fermentation of starch and sugar (e.g. corn, beets, sugar cane), advances are being commercialized for the conversion of lignocellulosic biomass through acids, enzymes, and gasification methods which improve the economics and reduce upstream energy intensity and emissions. The development of a nation-wide E85 infrastructure could lead to a viable biomass-to-hydrogen pathway via distributed or onsite ethanol reformation.

This project uses the Steam-reforming and Autothermal-reforming facilities.

Team Members: Jonathan Wooley, Matthew Caldwell

Reformer Design

Hydrogen production units have yet to be optimized for maximum conversion and selectivity and yield while reducing volume and associated mass.  Several research projects are in progress which seek to further the fundamental  understanding of reformation.  Studies include the proper design of reformers to handle steady state and transient operation, the mechanisms of catalyst degradation, and proper parameters for scale-up and scale-down of reforming technology.  Enhancement methods and clean-up units are also being investigated.

This project uses the Steam-reforming and Autothermal-reforming facilities.

Team Member: Hyung Chul Yoon, Chang-hsien Liao, David Vernon, Jon Hsu

Temperature Control System Improvements in SR and ATR processes

The proposed study will focus on reactor control for the production of hydrogen.  Specifically, the key aspect of the research is to study the fundamental physics and apply them to an observer-based control system for improving the overall reactor dynamics.  The most important advantage of Observers is the ability to reduce the number of sensors thus improving the robustness of both the system hardware and the responses of the controller.  The traditional sensor feedback control method is inadequate due to the inherent dynamics of the reactor and inaccessible desired state.  Implementation and experimental method are described in this proposal.

This project uses the Steam-reforming and Autothermal-reforming facilities.

Team Members: Ray Tang

Hydrogen Production through Electrolytic Processes

Electrolysis offers several advantages over other hydrogen production techniques which can include zero emissions at the production site, widely distributed supply and possible scalability for distributed or centralized production. Our focus is on solving problems with cost and overall efficiency through investigations of the underlying phenomenon in high temperature systems.

This project uses electrolysis facilities presently being designed..

Team Members: David Vernon

Hydrogen Utilization Studies

Hydrogen Enrichment of Various Fuels through Thermochemical Recuperation of Combustion Exhaust Gases

Hydrogen enrichment has demonstrated benefits in reducing emissions and increasing efficiency by enabling engine operation with very dilute fuel mixtures.  Hydrogen enrichment is possible with various primary fuels.  Some of the current challenges to implementing hydrogen enrichment on a large scale include the lack of hydrogen delivery and dispensing infrastructure as well as the high cost of on-board hydrogen storage. 

One potential solution to these challenges is to produce hydrogen from the primary fuel on-board the vehicle in a reformation process.  On-board reformation processes have been demonstrated for much more demanding fuel cell applications.  Combustion processes can use hydrogen mixtures with high carbon monoxide concentrations as well as unconverted hydrocarbons which allow much simpler, less expensive reformer technologies to be used than those required for fuel cell applications. 

The thermochemical recuperation process takes this one step further by either indirectly using the waste heat in the exhaust stream or by directly utilizing the exhaust gases taking advantage of the heat, water vapor and residual oxygen to drive the on-board reformation process.  In the Hydrogen Production and Utilization Laboratory at UC Davis we are developing a combustion model to predict the effects of different concentrations of hydrogen and reformate enrichment on a wide range of fuels including methane, landfill gas, gasoline, diesel and alcohols. 

We are in the beginning stages of a project to study the operation of an autothermal reformer using exhaust gases.  This study will investigate the effect of space velocity, inlet temperature and gas composition, as well as heat and mass transfer limitations on reformer performance using various primary fuels.  This parametric study of autothermal reformation using exhaust gases will improve the fundamental understanding of exhaust driven reformation processes.  This in turn may enable a viable solution to the current difficulties with hydrogen-enrichment technologies.

Team Members: Eddie Jordan, David Vernon, Jonathan Woolley

Land-fill Gas to Hydrogen (LFG-H2) Production Feasibility Study

Current land-fill gas use is geared towards electricity. The Hydrogen Production and Utilization Laboratory is working with the California Integrated Waste Management Board (CIWMB) and the California Biomass Collaborative to investigate two potential uses of land-fill gases:

1. Using hydrogen enriched landfill gases for use in advanced combustion;

2. Reforming land-fill gas into hydrogen for direct use in vehicles.

Recently, the Hydrogen Production and Utilization Laboratory has co-hosted the 2006 Land-fill Gas to Hydrogen Workshop in conjunction with California EPA and CIWMB to discuss LFG-H2 use.  For more information concerning this workshop, please access the Land-fill Gas to Hydrogen Conference Page.

Team Members: Kurt Lorenzo Kornbluth, David Vernon, Eddie Jordan, Ziv Rudolf Lang

 

Hydrogen Assisted Catalytic Light-off in Catalytic Converters

50% of vehicle emissions are produced during cold start due to the time delay needed to heat the catalytic converter to operational temperature. Previous studies performed by Lynntech have demonstrated that the addition of small quantities of hydrogen can increase the volatility of the air surrounding the catalyst and thus achieving quicker light off times and lower NOx emissions.           

This project uses the Autothermal-reforming facilities.

Team Members: Ziv Rudolf Lang,  Anthony Montevirgen, Todd Skinner

Fuel Cell Bus Research
	Vibration/Noise Study Comparison of PAFC Fuel Cell Bus and Diesel IC Bus. One of the First Generation Georgetown fuel cell buses has arrived as part of our research equipment.  This bus, known as Test Bed Bus -1, is one that was worked on extensively by Dr. Erickson while he was at the University of Florida. For more information on this Bus go to the Fuel cell bus facility web site.   This bus is used as a research and training tool for the lab. It was the first liquid-fueled fuel cell bus ever demonstrated and is one of five existing liquid-fueled fuel cell buses.  The bus uses methanol as a primary fuel and supplies hydrogen to a phosphoric acid fuel cell stack after processing a methanol/ water fuel mixture. The Fuel Cell Bus is run in a hybrid arrangement with three 200 Amp-hr 72 Volt Battery Packs.  This means that the fuel cell and battery packs supply the power for the load cycle.  During peak load demand, the batteries discharge. These batteries are recharged by the fuel cell when the load decreases as a charge sustaining strategy. Team Members: Zack Zoller
Liquid Oxidizers in Fuel Cell
	Modern Proton Exchange Membrane Fuel Cells (PEMFCs) operate with fuel and oxygenate streams both in the gaseous phase. However, the use of gases limits heat transfer.  This limitation is a significant challenge to the design of large power fuel cell systems because of the large cooling plates needed to cool the system. Improving the heat transfer is one of the solutions this problem. Using Per-fluorocarbons (PFCs) dissolved in oxygen can improve heat transfer properties in the PEMFC because PFCs have: Lower surface tension than water Higher density than water Similar kinematical viscosity to water These characteristics  may lead to more favourable mass transfer characteristics of dissolved oxygen diffusion between the PFC and the cathode. In addition, using PFCs may also reduce cathode activation losses due to the higher oxygen concentration in the PFC-oxygen mixture.  Liquid oxidizers have the potential to reduce the heat transfer resistance within the PEMFC and thus minimize the bipolar plate size. These advantages have industrial value because manufacturers could lessen the electrical resistance of the interconnects and also the cost of the whole system. Team Members: Phillip Voll