CHM 111 Lecture Notes - Lecture 16: Thermodynamics, Cellulosic Ethanol, Bottom Ash
27 Apr 2018
School
Department
Course
Professor
CHM 111: Tuesday, April 10th
Day 16 Notes
Chemistry in Modern Society
Conservation of Energy
• First Law of Thermodynamics
o The energy of the universe is constant, or, energy can never be created or
destroyed; but it can be converted from one form to another
Energy in a Power Plant
• Coal is used to create electricity in a power plant
o Combustion
▪ This is when the cooling water is pumped into a condenser and then
pumped into a burner
o Boil Water in a closer, high pressure system
▪ Once the water is in the boiler it is heated up to a high temperature so
that it will evaporate
o Turning of the turbine to create electricity
▪ The steam from the heated water will turn the turbine which then create
energy
CHM 111: Tuesday, April 10th
Day 16 Notes
Energy Transformation in a Power Plant
• Molecule with high potential energy make good fuels
Second Law of Thermodynamics
• The entropy of the universe is increasing
o Entropy is a measure of disorder
o Things naturally move towards a less disordered system (more entropy)
o We can cerate “order” but at a cost
Power Plant Efficiency
• No electric power plant can completely convert one type of energy into another
• Some of the energy is transferred unto useless heat (lost to universe)
CHM 111: Tuesday, April 10th
Day 16 Notes
o The higher temperature of the steam, the more efficient the power plant
Comparing Power Plant Efficiency
• If the Net Efficiency is higher that means that more usable energy can be produced per
day with less total energy used.
Energy in a Power Plant
• Fuel is used to create electricity in a power plant:
o Combustion: Fuel + 2O2 (g) CO2 (g) + 2H2O (l) + Energy
o Boil water in a closed, high pressure system Turn turbine to create electricity
• Potential KineticMechanicalElectrical
• Some usable energy is lost as heat in the universe because we are working against the
2nd law of thermodynamics (entropy is decreasing)
• Environmental concerns
o Byproducts of combustion
o Warming of cooling water sources
Different Types of Fuel
• Are all fuels created equal?
o Fuel + 2O2 (g) CO2 (g) + 2H2O (l) + Energy
Document Summary
Conservation of energy: first law of thermodynamics, the energy of the universe is constant, or, energy can never be created or destroyed; but it can be converted from one form to another. Energy transformation in a power plant: molecule with high potential energy make good fuels. Second law of thermodynamics: the entropy of the universe is increasing, entropy is a measure of disorder, things naturally move towards a less disordered system (more entropy, we can cerate order but at a cost. Power plant efficiency: no electric power plant can completely convert one type of energy into another, some of the energy is transferred unto useless heat (lost to universe) Day 16 notes: the higher temperature of the steam, the more efficient the power plant. If the net efficiency is higher that means that more usable energy can be produced per day with less total energy used.
