Alternative fuel technology MAT 1153 Alternative fuel technology Chapter 5 - Hydrogen & Fuel Cell Vehicle MOHD FAIRUS JAMID fairus@icam.edu.my

Hydrogen Fuel Cells: The power of tomorrow

What is a Fuel Cell? Is an electrochemical reactions device that combines hydrogen and oxygen to produce electricity, with water and heat as its by- product. Unlike a battery, chemicals are not stored in the fuel cell; they must be replenished Using a fuel and an oxidant Possible fuel sources: hydrogen, alcohols, hydrocarbons, gasoline Possible oxidants: oxygen, chlorine, chlorine dioxide

what is a fuel cell?

Structural characteristics of PEMFC membranes what is a fuel cell? Structural characteristics of PEMFC membranes

what is a fuel cell? Anode (-) and Cathode (+) on each side of the fuel cell, divided by an electrolyte Hydrogen gas is channeled through anode side; oxygen passes through cathode Platinum catalyst oxidizes hydrogen atoms into H+ and electrons Electrons pass along external circuit; conduct electricity before entering cathode Electrolyte allows H+ to pass into the cathode In cathode, catalyst combines H+ , O2- and electrons, forming H2O and heat

what is a fuel cell? Anode: 2H2 => 4H+ + 4e- Cathode: O2 + 4H+ + 4e- => 2H2O Net Reaction: 2H2 + O2 => 2H2O Exact opposite of electrolysis

what is a fuel cell?

what is a fuel cell?

Fuel cell stack components what is a fuel cell? Fuel cell stack components

Construction of Hydrogen Fuel Cell Vehicle

Construction of Hydrogen Fuel Cell Vehicle

Construction of Hydrogen Fuel Cell Vehicle

Construction of Hydrogen Fuel Cell Vehicle The P2000, zero-emission vehicle that utilizes a direct hydrogen polymer electrolyte fuel cell.

The complete fuel-cell stack system

How does a fuel cell work? A Fuel Cell consists of two catalyst coated electrodes surrounding an electrolyte One electrode is an anode and the other is a cathode The process begins when Hydrogen molecules enter the anode The catalyst coating separates hydrogen’s negatively charged electrons from the positively charged protons The electrolyte allows the protons to pass through to the cathode, but not the electrons Instead the electrons are directed through an external circuit which creates electrical current While the electrons pass through the external circuit, oxygen molecules pass through the cathode There the oxygen and the protons combine with the electrons after they have passed through the external circuit When the oxygen and the protons combine with the electrons it produces water and heat Individual fuel cells can then be placed in a series to form a fuel cell stack The stack can be used in a system to power a vehicle or to provide stationary power to a building

Fuel Cell vs. Battery

Fuel Cell vs. ICE

Glossary of Terms used in describing Fuel Cell Technology

Glossary of Terms used in describing Fuel Cell Technology

Types of Hydrogen Fuel Cells Polymer Electrolyte Membrane (PEM) Fuel Cells Direct Methanol Fuel Cells Alkaline Fuel Cells Phosphoric Acid Fuel Cells Molten Carbonate Fuel Cells Solid Oxide Fuel Cells Regenerative Fuel Cells

Types of Hydrogen Fuel Cells Electrolyte Operating Conditions Alkaline FC (AFC) Aq. KOH Operates at room temp. to 80 0C Apollo fuel cell Proton Exchange Membrane FC (PEMFC) Sulfonated Polymers Operates best at 60-90 0C Hydrogen fuel Originally developed by GE for space Phosphoric Acid FC (PAFC) H3PO4 Operates best at ~200 0C Stationary energy storage device Molten Carbonate FC (MCFC) (Na, K, Li)2CO3 Operates best at 550 0C Nickel catalysts, ceramic separator membrane Hydrocarbon fuels reformed in situ Solid Oxide FC (SOFC) YSZ Operates at 900 0C Conducting ceramic oxide electrodes Direct Methanol Fuel Cell (DMFC) Methanol Fuel For portable electronic devices

Types of Hydrogen Fuel Cells Proton Exchange Membrane (PEM) This is the leading cell type for passenger car application Uses a polymer membrane as the electrolyte Operates at a relatively low temperature, about 175 degrees Has a high power density, can vary its output quickly and is suited for applications where quick startup is required making it popular for automobiles Sensitive to fuel impurities. http://www1.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html#pem

Types of Hydrogen Fuel Cells

Present-Day Applications

Present-Day Applications

Experience - refueling

Hydrogen Source

Importance of Hydrogen Source Hydrogen is a secondary energy resource, meaning it must be made from another fuel Hydrogen can be produced from a wide variety of energy resources including: Fossil fuels, such as natural gas and coal Nuclear energy Renewable resources, such as solar,water, wind and biomass

hydrogen production The biggest challenge regarding hydrogen production is the cost Reducing the cost of hydrogen production so as to compete in the transportation sector with conventional fuels on a per-mile basis is a significant hurdle to Fuel Cell’s success in the commercial marketplace There are three general categories of Hydrogen production Thermal Processes Electrolyte Processes Photolytic Processes Natural Gas Reforming Gasification Renewable Liquid Reforming

hydrogen production Natural Gas Reforming Steam Methane Reforming Hydrogen is produced from methane in natural gas using high-temperature steam Methane reacts with the steam in presence of a catalyst to produce hydrogen This process accounts for about 95% of the hydrogen used today in the U.S. Partial oxidation Produces hydrogen by burning methane in air Gasification Process in which coal or biomass is converted into gaseous components by applying heat under pressure and in the presence of steam A subsequent series of chemical reactions produces a synthesis gas which reacts with steam to produce more hydrogen that can be separated http://www1.eere.energy.gov/hydrogenandfuelcells/production/natural_gas.html

hydrogen production Renewable Liquid Reforming Biomass is processed to make renewable liquid fuels, such as ethanol or bio-oil, that are then reacted with high-temperature steam to produce hydrogen This process is very similar to reforming natural gas Electrolytic Processes Electrolytic processes use an electric current to split water into hydrogen and oxygen The electricity required can be generated by using renewable energy technologies such as wind, solar, geothermal and hydroelectric power Photolytic Processes Uses light energy to split water into hydrogen and oxygen These processes are in the very early stages of research but offer the possibility of hydrogen production which is cost effective and has a low environmental impact http://www1.eere.energy.gov/hydrogenandfuelcells/production/liquid_fuels.html

hydrogen production

hydrogen storage Developing safe, reliable, compact and cost-effective hydrogen storage is one of the biggest challenges to widespread use of fuel cell technology Hydrogen has physical characteristics that make it difficult to store large quantities without taking up a great deal of space Hydrogen will need to be stored onboard vehicles, at hydrogen production sites, refueling stations and stationary power sites Hydrogen has a very high energy content by weight (3x more than gasoline) and a very low energy content by volume (4x less than gasoline) If the hydrogen is compressed and stored at room temperature under moderate pressure, too large a fuel tank would be required Researchers are trying to find light-weight, safe, composite materials that can help reduce the weight and volume of compressed gas storage systems Energy, Economics, and the Environment. Cases and Materials Second Edition. Chapter 15 Energy in Transportation p. 1200

hydrogen storage Liquid hydrogen could be kept in a smaller tank than gaseous hydrogen, but liquefying hydrogen is complicated and not energy efficient Liquid hydrogen is also extremely sensitive to heat and expands significantly when warmed by even a few degrees, thus the tank insulation required affects the weight and volume that can be stored If the hydrogen is compressed and cryogenically frozen it will take up a very small amount of space requiring a smaller tank, but it must be kept supercold- around -120 to -196 degrees Celsius Energy, Economics, and the Environment. Cases and Materials Second Edition. Chapter 15 Energy in Transportation p. 1200

Disadvantages Fuel cells require specific humidity, pressure, etc. Catalysts are pricey and sensitive to poisoning Difficult to produce hydrogen Difficult to store optimum amounts of Hydrogen If fuels other than hydrogen are used, some greenhouse gasses are emitted Very few cars currently running on hydrogen

Advantages Environmental Benefits - Reduce air pollution. Create less than one ounce of pollution per 1,000 kilowatt-hours of electricity produced Conventional combustion generating systems produce 25 pounds of pollutants for the same electricity The only byproducts of these Fuel Cell vehicles are water and heat Battery replacement/alternative Fuel Cell replacements for batteries would offer much longer operating life in a packaged of lighter or equal weight Additionally, Fuel Cell replacements would have an environmental advantage over batteries, since certain kinds of batteries require special disposal treatment It is a clean, quiet and highly efficient process- two to three times more efficient than fuel burning.

conclusion Hydrogen fuel cells are efficient, and clean Also expensive, and require specific humidity, temperature, pressure With more technological advancements, could be used in mass production for various applications Not an instant fix for the energy crisis, but definitely a major component Promising technology Most viable for niche market use in the near future Widespread marketplace acceptance and use is still many years away

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