introduction to bioenergy - dongguk...introduction to bioenergy 1 1. global warming and carbon cycle...
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Introduction to
Bioenergy
1
1. Global Warming and Carbon Cycle
Carbon Cycle
Carbon cycle
Carbon cycle is the biogeochemical cycle by which carbon is
exchanged among the biosphere, pedosphere, geosphere,
hydrosphere, and atmosphere of the Earth.
Along with the nitrogen cycle and the water cycle, the carbon
cycle comprises a sequence of events that are key to making
the Earth capable of sustaining life: it describes the
movement of carbon as it is recycled and reused throughout
the biosphere.
The global carbon budget is the balance of the exchanges of
carbon between the carbon reservoirs or between one
specific loop of the carbon cycle.
Carbon Cycle
Carbon cycle
An examination of the carbon budget of a pool or reservoir
can provide information about whether the pool or reservoir in
functioning as a source or sink for carbon dioxide.
Carbon-based molecules are crucial for life on earth, as it is
the main component of biological compounds.
Carbon is also a major component of many minerals. Carbon
also exists in various forms in the atmosphere. Carbon
dioxide is partly responsible for the greenhouse effect and is
the most important human-contributed GHG.
In the past two centuries, human activities have seriously
altered the global carbon cycle, most significantly in the
atmosphere.
Global warming
Global warming: Causes and effects
Earth’s temperature has resin about 1 degree Fahrenheit in
the last century. The past 50 years of warming has been
attributed to human activity.
GHGs are emissions that rise into the atmosphere and trap
the sun’s energy, keeping heat from escaping.
During the past 100 years global sea levels have risen 4-8
inches.
Damaging storms, droughts and related weather phenomena
cause an increase in economic and health problems. Warmer
weather provides breeding grounds from insects such as
malaria-carrying mosquitoes.
Global warming
Global warming: Causes and effects
Burning fuels such as coal, natural gas and oil produce GHGs
in excessive amounts.
Most of the world’s emissions are attributed to the large-scale
use of fuels in vehicles and factories.
Some predictions for local changes include increasingly hot
summers and intense thunderstorms.
The US was responsible for 20% of the global GHGs emitted
in 1997.
Carbon cycle & biofuels
Biofuels & biorefinery
• Thermochemical conversion
- Pyrolysis
- Gasification
- Liquefaction
• Biological conversion
- Bioethanol
- Biogas
• Chemical conversion
- Chemicals
Conversion of biomass
2. Biomass and Bioenergy
Individual energy consumption
Population, food and energy
Population vs. Energy
U.S. energy consumption by source
Biomass
Solar energy
Geothermal energy
Wind velocity
Wave power
Tidal power
Ocean thermal energy
(Nuclear energy)
New & Renewable
energy
Electric power
- Electric power - Solid, gas, liquid fuels, and chemicals
New & Renewable energy
Biomass
Biomass ?
Biomass is organic material made from plants and animals.
Biomass contains stored energy from the sun. Plants absorb the sun's energy in a process called photosynthesis. The chemical energy in plants gets passed on to animals and people that eat them.
Biomass is a renewable energy source because we can always grow more trees and crops, and waste will always exist.
Some examples of biomass fuels are wood, crops, manure, and some garbage.
Types and sources of biomass
Biomass fuels
• When burned, the chemical energy in biomass is released as heat. If you have a fireplace, the wood you burn in it is a biomass fuel. Wood waste or garbage can be burned to produce steam for making electricity, or to provide heat to industries and homes.
• Burning biomass is not the only way to release its energy. Biomass can be converted to other usable forms of energy like methane gas or transportation fuels like ethanol and biodiesel.
• Methane gas is the main ingredient of natural gas. Smelly stuff, like rotting garbage, and agricultural and human waste, release methane gas - also called "landfill gas" or "biogas."
Biomass fuels
• Crops like corn and sugar cane can be fermented to produce the transportation fuel, ethanol.
• Biodiesel, another transportation fuel, can be produced from left-over food products like vegetable oils and animal fats.
• Biomass fuels provide about 3 percent of the energy used in the United States.
• People are trying to develop ways to burn more biomass and less fossil fuels. Using biomass for energy can cut back on waste and support agricultural products.
• Biomass fuels also have a number of environmental benefits.
3. Photosynthesis
Biomass & Photosynthesis
Classification of biomass for biofuels
Woody plants
Herbaceous plants
Water plants
Algae
Microalgae
Agricultural & Forest products wastes
Biomass
Characteristics of biomass resources
• Advantages Renewable and sustainable resources
Environmentally friendly clean energy resources
Carbon neutral
Uniform distribution worldwide
Multipurpose resources and easy utilization
• Disadvantages High gathering cost (huge distribution area & volume)
Pretreatment needed in its utilization
Low energy level
Variable production yield according to the environments