CHM 111 Lecture Notes - Lecture 17: Nuclear Reaction, Critical Mass, Concentrated Solar Power
27 Apr 2018
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CHM 111: Thursday, April 12th
Day 17 Notes
Chemistry in Modern Society
Biofuels: What needs to be done
• Motivation:
o U.S. used 4 trillion gallons of petroleum-based fuels in 2015
o U.S. produced 14 billion gallons of bioethanol in 2015
• Bioethanol
o Grain ethanol: improve production efficiency
o Cellulosic bioethanol: improve enzymes for cellulose digestion
• Biodiesel
o Improve efficiency, promote use
• Bio Jet Fuel
o Expand production facilities
• Algal Biodiesel
o Develop new algae strains
o Improve extraction and conversion of algae lipids to biodiesel
The Future of Fuel
What Else is There?
CHM 111: Thursday, April 12th
Day 17 Notes
What else is there?
Wind
• Large Blades are moved by wind spin a shaft to turn a generator electricity
• Wind Farms can generate as much power as nuclear/coal
o 1,548 MW of electricity from Alta Wind Energy in CA
o Cons: land right issues, environmental concerns (birds)
▪ Large scale, land availability, weather factor
o Future: off-shore wind farms (used in the UK)
Water/Geothermal
• Hydro: dams holds back water (potential energy) falling water (kinetic energy) spins
turbine electricity
o Environmental Concerns
▪ How are the fish going to swim upstream?
CHM 111: Thursday, April 12th
Day 17 Notes
▪ Is it really good to change the landscape for creating energy?
• Geothermal: heat from the core of the Earth; drill into underground reservoirs
containing hot water or steam
o Hawaii: 20% of power from geothermal
o Miami University: 300 geothermal pools to heat/cool Western
Solar Power
• Using light energy from the sun to generate electricity
o Not always sunny in the same places, intensity varies by location
• Two methods:
o Concentrating Solar Power (CSP): mirrored arrays concentrate light to produce
heat steam turbineelectricity
o Photovoltaic Cell (PV): converts light energy directly into electrical energy; can be
connected into arrays to produce more power
▪ Can provide maintenance free power; bring power to remote areas
• Cons: costly to make PV cells, conversion to electricity not efficient (max 21%), mining
concerns (safety and toxicity), land use (would need PV cells covering area size of New
Jersey to supply enough power for US
Document Summary
Improve efficiency, promote use: bio jet fuel, expand production facilities, algal biodiesel, develop new algae strains. Improve extraction and conversion of algae lipids to biodiesel. Nuclear power in the us: currently, around 20% of electrical power in the united states is produced by nuclear power plants, we produce the most power from nuclear overall, 100 nuclear reactors at 61 sits in 20 states. Nuclear fission: the splitting of a large nucleus into smaller ones with the release of energy, energy is released because the sun of the masses of these fragments is less than the original mass. Nuclear reactions: nuclear fission initiated by neutrons, not all nuclei are created equal, only u-235 will undergo fission in a reactor. Enriching uranium: why u-235, this process is extremely difficult, need 5% u-235 for power, need 85% of u-235 for weapons, depleted uranium (u-238) can be converted into plutonium. **** all pictures and charts are taken directly from the class presentations****
