hydrogen energy: an overview kenneth m. klemow, ph.d. wilkes university
TRANSCRIPT
Hydrogen Energy: An Overview
Kenneth M. Klemow, Ph.D.
Wilkes University
www.rise.org.au
www.inl.gov/
www.fuelcellstocks.com
Points to be covered Some hydrogen chemistry Hydrogen as an energy source Producing hydrogen Benefits of hydrogen as an alternative fuel Hydrogen power initiatives Disadvantages of hydrogen The WebQuest
Some hydrogen chemistry
Lightest element (consists of only one proton and one) electron
Isotopes include one or more neutrons
Most abundant element in universe (75% by mass)
Component of most stars; as plasma
discovermagazine.com
Hydrogen on earth Easily reacts with most other elements,
particularly oxygen, carbon, nitrogen, most metals.
Carbon-hydrogen compounds are basis of organic chemistry.
Basis of acid-base reactions. Occurs in diatomic form in atmosphere At typical temperatures and pressures, H2 is
a gas. Rare (ca. 1 ppm) due to ease of escape
Molecular hydrogen is combustible
2 H2(g) + O2 (g) → 2 H2O(l) H = -286 kJ/mol
Burns at concentrations
as low as 4%. Produces flame visible
only in UV spectrum
Primary industrial uses of hydrogen Create ammonia
3 H2 + N2 → 2 NH3
Cracking of high molecular weight hydrocarbons to form low m.w. hydrocarbons
Hydrogen as an energy source
Fuel for internal combustion
engines
www.global-hydrogen-bus-platform.com
Fuel cells
www.evworld.com
Hydrogen internal combustion engines
Cadillac
Hondawww.london.gov.uk
London Olympics
Hydrogen fuel cells
www.next-generation.caAnimation
Have many kinds of fuel cells Proton Exchange Membrane (PEM)
Run at low temperatures, used in automotive applications
Solid Oxide Fuel Cells Use ceramic electrolyte, central generating
stations Alkaline Fuel Cells
Long used by NASA in spacecraft Regenerative fuel cells
Self contained, uses water and sunlight Microbial fuel cells
Use bacteria and yeast under anaerobic cond.
How is hydrogen produced? Reacting metals with acids
Zn + 2 H+ → Zn2+ + H2
Processing hydrocarbons CH4 + H2O → CO + 3 H2
H = +191.7 kJ/mol
Hydrolysis of water 2H2O(l) → 2H2(g) + O2(g)
G = +474.4 kJ/mol
Commercial hydrogen production As a byproduct of coal gasification and
natural gas processing Through use of electricity generated by
burning fossil fuels, nuclear, solar, hydropower, geothermal, wind
The hydrogen economy
Elements of the hydrogen economy Hydrogen generation
Centralized Distributed
Hydrogen storage Hydrogen distribution
Benefits of hydrogen as a fuel Hydrogen exists in an unlimited supply Hydrogen is renewable Hydrogen is clean-burning
Water is main byproduct No carbon dioxide released into air
Hydrogen weighs less and generates more power than hydrocarbon-based fuels.
Hydrogen burns faster and at a lower temperature than conventional gasoline
Convert vehicles to hydrogen power Establish extensive distribution system
for hydrogen Produce massive amounts of hydrogen
No worries about carbon if using nuclear, wind, geothermal, hydropower
Use carbon sequestration techniques if using fossil fuels
The vision
Initiatives Hydrogen.gov Minnesota Renewable Hydrogen initiative National Hydrogen Association BP and GE Hydrogen initiative Icelandic Hydrogen Energy Germany Clean Energy partnership Japan Hydrogen and Fuel Cell demo project
Disadvantages of hydrogen power Hydrogen is difficult to contain; tanks are bulky Hydrogen reacts with metal in tanks causing them
to become brittle Hydrogen is explosive, can be unsafe Fuel cells are expensive, especially due to platinum
catalysts Hydrogen is an energy carrier; have inherent
inefficiencies in generation. Production via fossil fuel combustion still releases
carbon dioxide - large scale sequestration may not be feasible.
Establishing distribution facility will cost trillions of dollars
Pellet of ammonia borane weighting 240mg. Can store 0.5 L of hydrogen in small volume.
www.sciencedaily.com
So, is hydrogen power the answer to our energy concerns?
You tell me!