Biomass Facts by huangyuarong

VIEWS: 21 PAGES: 174

									Biomass role in Energy consumption
Figure 4-1: Biomass Role in U.S. Energy Consumption
Figure 4-2: Photosynthesis
Figure 4-3: Greenhouse Gas Emissions
There are significant advantages as well as
concerns raised when biomass is harvested as
a fuel source. Advantages include:
  Biomass is renewable. Properly managed, new
  fuel sources can be planted to replace those that
  are harvested.
  It is virtually carbon neutral. The crop planted to
  replace the crop converted to fuel (ethanol in this
  example) will in theory absorb the greenhouse
  gas emissions generated by burning the biofuel.



                                               (continued)
There are significant advantages as well as
concerns raised when biomass is harvested as
a fuel source. Advantages include: (continued)
  Biomass is relatively inexpensive. Biofuels can
  be manufactured at costs comparable to fossil
  fuel sources.
  It reduces dependency on non-renewable
  imported oil and gas.

  Biomass supports the growth of agriculture,
  forestry and other rural economic development.


                                               (continued)
There are significant advantages as well as
concerns raised when biomass is harvested as
a fuel source. Advantages include: (continued)
   It helps to stabilize commodity prices by
   providing a consistent and large demand source.
   Biofuels are non-toxic and biodegradable.
   Often no modifications to conventional internal
   combustion engines are required to use biofuels.

   It takes advantage of wasted potential energy by
   harvesting waste products that otherwise would
   simply end up in a landfill.
Figure 4-4: The Biofuel Carbon Cycle
The disadvantages of biomass as a fuel source
include:
   Food versus Fuel. There is a concern that if the
   growing of biofuels proves more lucrative than
   the growing of food, farmers will convert their
   land to producing fuel and food production will
   decline. It is feared that this will lead to massive
   food shortages and higher prices. In 2008, over a
   six-month period of time, the price of corn
   increased 67% largely due to a perception that
   ethanol production would consume a significant
   amount of the corn production.
   Berkley Perspective
                                                  (continued)
The disadvantages of biomass as a fuel source
include: (continued)
 Not enough biomass. There are concerns that there
 simply is not enough biomass on the planet to meet
 current and anticipated energy demands. A 2003
 study found that it would require 22 percent of all the
 plant matter grown each year worldwide to supply
 biofuel to meet the needs of current energy demands
 (this is roughly twice what is currently utilized to
 supply the agricultural needs of the planet). For
 example, if ALL the corn produced in the U.S. was
 converted to ethanol, it would only supply 10% of the
 energy currently supplied by gasoline.
                                                (continued)
The disadvantages of biomass as a fuel source
include: (continued)
   Not carbon neutral. Depending on the crop used in the
   biofuel conversion, the process may not be carbon neutral
   as it often takes a significant amount of fossil fuels to grow
   the crop. Studies in the UK have found that biofuels in
   their current form save only about 50-60% of the carbon
   emissions as compared to burning fossil fuels. This is
   significant, but not the 100% claimed by many proponents
   of biofuels. The U.S. Environmental Protection Agency
   (EPA) has found that when land use conversion is factored
   into the production of ethanol (forests, for example, cut
   down to plant corn) - using ethanol actually INCREASES
   greenhouse gas emissions by 5% over a 30-year period of
   time.
                                                         (continued)
The disadvantages of biomass as a fuel source
include: (continued)
   Fear of impact. There is a fear that if a significant
   portion of the agricultural land is dedicated to
   crops to support biofuels, biodiversity will suffer
   (for example, rain forests may be cut down to
   support biofuel “plantations.”) Deforestation
   currently accounts for about a fifth of the world’s
   greenhouse-gas emissions, according to
   Greenpeace.



                                                  (continued)
The disadvantages of biomass as a fuel source
include: (continued)
   Soil Erosion. Intensive land management for
   increased crop yields has resulted in significant
   soil erosion. The Iowa Natural Resources
   Inventory has found that land used to produce
   crops for ethanol loses about 4.9 tons of soil per
   acre. This is the equivalent of 21 pounds of soil
   for every gallon of fuel (2.5 kilograms per liter).




                                                 (continued)
The disadvantages of biomass as a fuel source
include: (continued)
   Airborne Pollution. The burning of biomass
   releases a large number of airborne particulates.
   This can be a major health concern, especially in
   developing nations where biomass is a major
   source of fuel for cooking and heating.
Many powerful groups have lobbied government
officials to incorporate biofuels as a significant
component in a national energy policy. Some of
these initiatives include:

       20 in 10: In 2007 U.S. President George W.
       Bush announced an initiative targeting a
       20% reduction in fossil fuel consumption
       within 10 years (2017) primarily through
       the use of biofuels.




                                               (continued)
Many powerful groups have lobbied government
officials to incorporate biofuels as a significant
component in a national energy policy. Some of
these initiatives include: (continued)

     25 x ‘25: A non-partisan lobbying effort
     (promoted primarily by agricultural and
     forestry industry interests) began in 2004 to
     promote a national policy resulting in 25% of
     all fuel consumption in the U.S. obtained from
     managed agricultural and forestry sources by
     the year 2025.


                                               (continued)
Many powerful groups have lobbied government
officials to incorporate biofuels as a significant
component in a national energy policy. Some of
these initiatives include: (continued)

      The Biomass Technical Advisory Committee:
      A committee established by the U.S. Congress
      to determine the future direction of federal
      biomass funding. A report published in 2005
      envisioned a domestic energy market where
      30% of energy consumption was supplied
      from biomass.
Figure 4-5: Annual Biomass Production Targets
In order to achieve U.S. government projected
goals, however, a number of assumptions were
made. These include:
   Yields per acre for corn, wheat and other small
   grains will increase by more than 50% over the
   coming years
   The technology for recovering crop residue
   (materials left behind when harvesting)
   improves to become 75% efficient (currently
   less than 40% efficient)



                                              (continued)
In order to achieve U.S. government projected
goals, however, a number of assumptions were
made. These include: (continued)
   All cropland (100%) will be managed using
   no-till methods (a process of harvesting where
   crop residue is left on the surface of the soil - no
   plowing - to ensure consistent soil moisture and
   temperature for future planting), up from about
   13% today
   55 million acres of cropland and pasture will be
   converted to growing perennial biomass crops
   (such as switchgrass, willow and other woody
   materials)
                                                 (continued)
In order to achieve U.S. government projected
goals, however, a number of assumptions were
made. These include: (continued)
   No significant increase or reduction in farming
   acreage (from current agricultural inventories
   of 455 million acres to 448 million acres in 2030)

   All manure except that which is applied on the
   farm where it is produced for soil embellishment
   will be used as biomass

   All available residuals (zero waste) will be used
   as biomass
Figure 4-6: Potential Sources for Biomass
Anticipated sources for biomass include:

Logging and other timber residues (branches,
stumps, etc.) through forest management
(Silviculture)
Fuel treatment (removing excess brush and trees
to manage forests in an effort to avoid damaging
forest fires)
Firewood (for wood stoves, furnaces, etc.)
Urban wood residues (such as tree trimmings,
wood from demolished homes, etc.)

                                             (continued)
 Anticipated sources for biomass include:
 (continued)

Pulp residues (black liquors from paper processing
contain chemicals and unprocessed pulp.
Technology to gasify these liquors may provide a
more efficient energy source than simply burning
them.)

Bark, slabs and sawdust from wood processing
Grains (factoring in increased yields)
Perennial crops such as switchgrass, poplar and
willow
                                            (continued)
Anticipated sources for biomass include:
(continued)
Crop residues (corn stalks, etc)
Process residues (waste material collected when
plant material is used in the production cycle).
These include manure from animals, municipal
waste, industrial waste (for example, about 20%
of the corn kernel is wasted when corn is
converted to ethanol), and others.
Achieving U.S. government projected targets
envisions a significant increase in the harvesting
of residual crop materials. However, these
materials serve some very useful purposes when
left in the field. They:

     Reduce soil erosion
     Reduce soil compaction
     Increase the organic content of the soil
     Increase moisture holding capacity of the soil


                                                (continued)
Achieving U.S. government projected targets
envisions a significant increase in the harvesting
of residual crop materials. However, these
materials serve some very useful purposes when
left in the field. They: (continued)

     Reduce the need for pesticides and fertilizers
     Provide food and habitat for wildlife,
     including beneficial soil enhancing organisms
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include:
    Accessibility to forests. Much of the available
    biomass contained within forests is simply
    not accessible (no roads, steep terrain, etc).
    Public resentment. If large swaths of timber
    were harvested to provide energy, public
    sentiment may quickly turn against biomass
    as an alternative fuel source.


                                                (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Transportation costs. Moving timber can cost
    between $.20-.60 per mile per ton. Unless
    conversion facilities are located close to the
    source, this transportation cost will add
    significantly to the cost of utilizing biofuels
    as an energy source.



                                                (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Labor availability. A significant portion of the
    biomass from woodlands is obtained through
    reducing the fuel load to prevent forest fires.
    This requires skilled forestry workers in
    numbers that are likely not available.




                                                (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Federal policy. Forest management is a long-
    term process. Government policies currently
    do not provide significant incentives for
    programs such as tree planting and
    woodlands management (less than ½ of one
    percent of agricultural payments to farmers).



                                             (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Contamination of materials. Recovered wood
    products (from urban residue and industrial
    residue) can add significantly to the cost of
    processing. These materials often contain
    non-biomass components (plastics, asbestos,
    oil paints, etc) that must be cleaned or
    removed during processing.


                                              (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Changing farming habits. Utilizing crop
    residues, no-till farming, and conversion to
    perennials require significant changes in the
    culture of farming. These farming practices
    are slow to change unless there are
    significant financial incentives.



                                              (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Damage to the soil. Removing residuals from
    the soil will likely lead to lower soil quality
    (need for additional fertilizers) as well as
    increased soil erosion. Raising corn, for
    instance, erodes the soil about 12 times faster
    than it can naturally be replenished.



                                               (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Water. Increasing production will almost
    certainly require additional water resources
    - many of which are already unreliable and
    stretched to capacity. Again, the production
    of corn depletes ground water 25% faster
    (on average) than it can be recharged.



                                             (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Crop Storage. Farming is seasonal, with
    periods of plenty and periods of low
    production. During times when harvests are
    good, there may be need for significant
    storage facilities to handle the excess
    production. These infrastructure needs add
    cost and complexity to the system.


                                           (continued)
Other concerns in achieving U.S. government
projected targets by a significant increase in
the harvesting of residual crop materials
include: (continued)

    Concentration of Resources. Many fear that
    biofuel production will increasingly
    concentrate control of food resources and
    prices within large agri-business producers
    and processors (accelerating the trend away
    from small family farm production).
In 2005 a group of about 100 non-profit non-
governmental organizations (NGOs) wrote to
the United Nations warning that increased use
of biofuels will:

     Marginalize small-scale agriculture and lead
     to the widespread conversion of forests and
     other sensitive ecosystems

     Lead to very high food prices and cause
     hunger, malnutrition and impoverishment
     amongst the poorest sectors of society


                                              (continued)
In 2005 a group of about 100 non-profit non-
governmental organizations (NGOs) wrote to
the United Nations warning that increased use
of biofuels will: (continued)

   Lead to rural unemployment and depopulation
   Destroy the traditions, cultures, languages and
   spiritual values of indigenous peoples and rural
   communities
   Lead to a more extensive use of agro-chemicals,
   which will affect human health and sensitive
   ecosystems

                                              (continued)
In 2005 a group of about 100 non-profit non-
governmental organizations (NGOs) wrote to
the United Nations warning that increased use
of biofuels will: (continued)

    Lead to the destruction of watersheds and the
    pollution of rivers, lakes and streams
    Cause droughts and other local and regional
    climatic extremes (due to deforestation)

    Put the food system at risk through the
    extensive use of genetically modified organisms
    (in an effort to boost crop production).
Initiatives such as the 25 x ‘25 publish
a list of goals that are incorporated into
biomass proposals to address concerns
such as:

 Access: All producers, large and small must
 have access to the biomass marketplace
 Air Quality: Use of biomass must improve air
 quality, not damage it. Use of biomass must
 also result in a net decrease in greenhouse gas
 emissions.



                                            (continued)
Initiatives such as the 25 x ‘25 publish
a list of goals that are incorporated into
biomass proposals to address concerns
such as: (continued)

Biodiversity: Native, rare and threatened plant
and animal species must be protected.
Invasive and Non-Native Species: Invasive
species must not be introduced in an effort to
increase biomass yields.




                                           (continued)
Initiatives such as the 25 x ‘25 publish
a list of goals that are incorporated into
biomass proposals to address concerns
such as: (continued)

Soil Quality: Biomass production should seek to
enhance soil quality and avoid erosion.
Water Quality and Quantity: Production of
biomass should not adversely impact available
water resources or water quality.
There exist a number of alternative sources that
hold promise in producing significant quantities
of fuel. These include:

                Municipal waste
                Food and crop waste
                Animal waste
                Algae
                Switchgrass
Figure 4-7: Inexpensive Biodigestor
Figure 4-8: Mature Switchgrass
All organic material contains the potential for
energy which can be extracted in a number of
ways. These include:
    Combustion: Biomass can simply be burned to
    generate heat and/or electricity. Since the dawn
    of time, wood has been used as a primary heat
    source. Today about 3% of the U.S. electrical
    energy is obtained through the burning of
    wood, wood waste and municipal waste.




                                               (continued)
All organic material contains the potential for
energy which can be extracted in a number of
ways. These include: (continued)
    Gasification: Biomass can be heated to form a
    synthetic gas call Syngas. Syngas can then be
    used to generate electricity or can be converted
    into fuels such as ethanol, methanol or
    hydrogen.




                                               (continued)
All organic material contains the potential for
energy which can be extracted in a number of
ways. These include: (continued)
   Fermentation and Biodigestion: The sugars
   contained within plant material can be broken
   down by yeast to produce carbon dioxide and
   alcohol. This process is known as Fermentation
   and is the basis for ethanol production. Similarly,
   the organic material in biomass can also break
   down to form methane and carbon dioxide. This
   process (known as biodigestion), as well as
   fermentation, are both anaerobic processes
   (taking place in oxygen-free environments).
Figure 4-9: Pellet Stove
Advocates of the Woodchip Boiler technology point to
the following advantages of woodchips:

     The price of woodchips is relatively stable or
     they can often be obtained for free from wood
     trimming activities (such as clearing for
     power lines).
     The energy required to create wood chips is a
     fraction of that required to produce wood
     pellets.
     Green chips can be used, eliminating the need
     to dry or season wood.

                                                (continued)
Advocates of the Woodchip Boiler technology point to
the following advantages of woodchips: (continued)

       Chips can be transported by dump truck
       (reducing handling and cost) and are
       typically produced from local sources.

       Wood chips can be produced from waste
       material or brush.
Figure 4-10: Reliance on Biomass in Developing Nations
Biopower system technologies include:

           Direct-firing
           Co-firing
           Pyrolysis
           Gasification (syngas)
           Anaerobic digestion
Table 4-1:
Average Heat
Content from
Various Biomass
Sources
Table 4-2: Energy and Bulk Densities Characteristics
               of Selected Materials
Figure 4-11: Wood-to-gas Converted Vehicle
The anaerobic digestion process generates three
main products:
      Biogas - a mixture of carbon dioxide (CO2)
      and methane (CH4)

      Fiber - can be used as a nutrient-rich soil
      conditioner

      Liquor - can be used as liquid fertilizer
The two major anaerobic digestion process:

                Mesophilic

                Thermophilic
Officially recognized alternative fuels (by the
U.S. Government) include:
    Methanol, ethanol and other alcohols
    Blends of 85 % or more alcohol with gasoline
    Domestically produced natural gas
    Liquefied petroleum gas (propane)
    Coal-derived liquid fuels
    Hydrogen
    Electricity
    Biodiesel (B100)
    Green Diesel (fuels other than alcohol derived
    directly from biological materials)
Figure 4-12: Annual U.S. Ethanol Production
Alcohol fuels offer significant advantages over
gasoline. These advantages include:
   Lower emissions: Ethanol contains oxygen,
   making the combustion process within the engine
   more efficient. As a result, the fuel burns cleaner
   with less carbon monoxide, nitrogen oxides and
   other greenhouse gases emitted.
   Higher octane: Ethanol boosts the octane content
   of the fuel mix (113 versus 87 for regular unleaded
   gasoline) without toxic chemicals such as benzene,
   toulene and xylene (which are often used for this
   purpose).
                                                 (continued)
Alcohol fuels offer significant advantages over
gasoline. These advantages include: (continued)
   Biodegradable: If accidentally spilled, ethanol will
   naturally degrade, leaving no lasting
   environmental impact.

   Domestic supply: Supports a domestic agricultural
   economy
   Proven technology: The production of alcohol is a
   time-tested technology and the resulting product
   can be used in existing internal combustion
   engines without significant modification.
Disadvantages of alcohol fuels include:

Food versus Fuel: In 2006, 17% of the U.S. corn
crop was used in the production of ethanol.
During that same year, the price of corn shot up
66%, largely based on increasing ethanol
production demands. Producing a significant
portion of domestic fuel production from food
crops raises serious concerns. It is estimated that
the amount of corn necessary to produce enough
ethanol to fill an SUV one time will feed a person
for a year.


                                              (continued)
Disadvantages of alcohol fuels include:
(continued)

Available resources: Critics argue that there
simply is not enough suitable farmland to
produce the amount of grains necessary to
manufacture ethanol in the quantities required.
The amount of farmland in the U.S. has actually
declined during the past 50 years, as shown in
Figure 4-13.




                                          (continued)
Figure 4-13: U.S. Cropland
Disadvantages of alcohol fuels include:
(continued)

 Production energy costs: Some scientists have
 argued that it requires up to six times the
 amount of fossil fuels to produce ethanol than
 the energy contained within the final product.
 Industry proponents counter that these estimates
 are flawed and/or are based on older production
 techniques.




                                          (continued)
Disadvantages of alcohol fuels include:
(continued)

 Lower energy content: Ethanol contains less
 energy for a given volume than does gasoline
 (83,333 Btu per gallon versus 124,800 Btu). As
 a result, vehicles will experience lower mileage
 per gallon.




                                             (continued)
Disadvantages of alcohol fuels include:
(continued)

Distribution issues: Ethanol-blended fuels are
corrosive and tend to separate when transported
in pipelines. Therefore, ethanol blends cannot be
shipped by pipeline - adding significantly to
transportation costs. Additionally, grain
production is rural in nature. Grain-based fuels
will incur considerable costs moving the product
to population centers.



                                            (continued)
Disadvantages of alcohol fuels include:
(continued)
Infrastructure: Higher ethanol blends (such as
E85) require custom pumps and storage tanks.
As a result, E85 is available at less than 1% of
gasoline retail stations.
Flex-fuel vehicles: In order to burn fuel blends
greater than 10% ethanol, vehicles must be
specially adapted. Flexible fuel vehicles can burn
blends up to 85% ethanol (E85). While numbers
are growing, E85 vehicles still represent a
minority of cars on the road.
Figure 4-14: Projected Biofuel Feedstocks
The Cellulosic Biofuel technology advantages
include:

 Available resources: Cellulosic biofuel production
 offers perhaps the only viable solution to large
 production demands based on available resources.
 Studies indicate that an efficient conversion
 process could produce significant amounts of
 biofuel from currently available waste materials
 and perennial crops that can be produced on
 marginally productive farmland.



                                             (continued)
The Cellulosic Biofuel technology advantages
include: (continued)
 No fertilizers and pesticides: A major energy input
 in traditional biofuel production is the need for
 fertilizers and pesticides in the production of
 grains. Most of these fertilizers are fossil-fuel
 based. Cellulosic materials require little or no
 fertilizers or pesticides.
 Lignin: Cellulosic biomass contains Lignin, a
 natural fiber that can also serve as an energy-rich
 fuel to run biofuel processing plants. These plants
 might operate solely on the energy supplied by
 this byproduct of production.
The Cellulosic Biofuel Technology disadvantages
include: (continued)
   High cost: The cost of producing cellulosic ethanol
   is much higher than costs associated with
   traditional production methods. It is hoped that as
   the technology matures, these costs will decline.
   Biodiversity damage: Increased production
   demands may lead to the introduction of invasive
   species, and damage to biodiversity (diverse
   environments converted to mono-crop
   production).
    The Butanol advantages include:

Vehicle modifications: Butanol can be blended at
higher rates with gasoline without the need for
modifications to the vehicle. It is considered
“substantial similar” to gasoline and some
advocates claim it can be substituted up to 100%
as a total replacement to gasoline in unmodified
vehicles.




                                            (continued)
The Butanol advantages include: (continued)

   Transportation: Butanol does not break down
   in pipelines, so it can be transported using
   traditional methods, reducing costs.
   Higher energy content: The energy contained
   in butanol (110,000 Btu per gallon) is much
   closer to gasoline (124,800 Btu per gallon)
   than ethanol. So vehicle miles-per-gallon
   would not be affected as dramatically.
 The Butanol disadvantages include:

Untested: This technology is not commercially
available, so all benefits are theoretical at the
present time.
Low yields: Industrial production of butanol
produces relatively low yields (in the 15-25%
range) of fuel.
Costs: As an experimental technology, butanol
production is very expensive when compared
to alternative fuels.
Figure 4-15: World Biodiesel Production
Table 4-3: Average Vegetable Oil Yields (per acre)
         from Common Biodiesel Crops
       Biodiesel advantages include:

Compatibility: Biodiesel can be used in any modern
diesel engine without modification.
Cleaner burning: Biodiesel burns cleaner within a
diesel engine than does traditional diesel fuel and
possesses excellent lubricating properties - which
can extend the life of the engine.
Higher efficiency: Biodiesel burns more efficiently
than does Petrodiesel (diesel fuel from petroleum).
This results in lower emissions.


                                              (continued)
Biodiesel advantages include: (continued)

Lower carbon emissions: As with all biofuels, the
energy from biodiesel comes from plant material,
the growing of which (theoretically) offsets the
carbon emissions from burning the product. The
U.S. Department of Energy estimates that biodiesel
emits 78% less carbon dioxide than does petrodiesel.
Odors: Diesel fuel and diesel engine emissions
produce an odor most find unpleasant. The burning
of biodiesel, however, produces a odor that smells
faintly of french fries if produced with recycled
cooking oil.
                                             (continued)
Biodiesel advantages include: (continued)

Biodegradable: Like ethanol, biodiesel spills will
degrade naturally, leaving no lasting impact on the
environment.

Higher flash point: Biodiesel has a flash point twice
as high as petrodiesel, making it less likely to ignite
when the diesel vehicle is involved in an accident.




                                                (continued)
Biodiesel advantages include: (continued)

Heating oil: Number 2 heating oil is essentially the
same a petrodiesel. Biodiesel blends up to 20%
(20% biodiesel) can be used in conventional fuel
oil furnaces (just as in diesel engines) with no
modification to the equipment. Residential
consumption of No. 2 heating oil in the U.S. was
6.6 billion gallons (25 billion liters) in 2001.
Blending heating oil (with 20% biodiesel) would
result in an additional 1.3 billion gallons (5 billion
liters) of biodiesel production.
       Biodiesel disadvantages include:

Lower energy: The energy content of biodiesel is lower
than that of traditional petrodiesel (121,000 Btu per
gallon as compared with 129,000 Btu per gallon). This
lower energy content results in about a 5% decrease in
power and fuel efficiency for biodiesel.

Bacteria: In warmer climates, bacteria may grow
within fuel tanks, clogging filters and fuel lines. This
occurs with both petrodiesel and biodiesel - although
tests indicate that adding biodiesel may accelerate
the problem. Fuel additives (biocides) are available
to eliminate this problem.
                                                 (continued)
Biodiesel disadvantages include: (continued)

  Cold weather: Diesel engines are often difficult to
  start in cold climates. This is because petrodiesel
  forms paraffin wax crystals (“clouds”) when the
  operating temperature falls below 20°F (-7°C).
  When temperatures fall to 5°F (-15°C) the fuel can
  reach a Pour Point, where it thickens and will not
  flow through fuel lines. Biodiesel clouds and gels
  at warmer temperatures than does petrodiesel.
  Complicating matters, biodiesel made with
  different oil feedstock will gel at different
  temperatures.

                                              (continued)
Biodiesel disadvantages include: (continued)

 Dissolves rubber: In older vehicles, low quality
 plastics and natural rubber can be dissolved by
 biodiesel. This is likely not a problem on vehicles
 produced after 1994.
 A good solvent: Biodiesel is an excellent solvent that
 will break down and loosen deposits left in the fuel
 tank and fuel system by conventional diesel fuel.
 This is a good thing (as they fuel system will be
 cleaned) but is also a bad thing in that fuel filters
 may become clogged with loosened material.
Straight Vegetable Oil disadvantages include:
  Conversion: The burning of SVO requires
  extensive conversion of the vehicle. Adapting a
  vehicle (even for a do-it-yourself mechanic) will
  cost between $300-$1,500.
  Engine damage: SVO as a fuel requires switching
  between fuel sources. Any miscalculations may
  result in severe engine damage.
  City driving: This system is not practical for short
  trips, as the SVO does not reach temperatures
  necessary to operate within the engine.

                                                 (continued)
Straight Vegetable Oil disadvantages include:
(continued)

   Filters: SVO systems require the yellow grease
   be extensively filtered, both before it is put in
   the tank and after. Fuel filters typically must be
   changed every 200-300 miles.
   Approvals: SVO is not an EPA-approved fuel.
   Use will void engine manufacturer’s warranties.




                                                 (continued)
Straight Vegetable Oil disadvantages include:
(continued)

   Glycerine: The glycerine which is the waste
   product in the production of biodiesel is still
   present in SVO. As the fuel burns, the glycerine
   may leave deposits within the system, reducing
   the life of the engine.
   New engine damage: Newer diesel engines
   equipped with catalytic converters were never
   intended to run on SVO and can very quickly
   be damaged or “poisoned”.
     Green Diesel advantages include:

Better performance: Green diesel is essentially
identical to petrodiesel, but with a few advantages.
It has a lower cloud point, so cold weather
performance is actually better than traditional
diesel fuels (and much better than biodiesel). It also
has a higher energy content than biodiesel (123,000
Btu/gallon vs 121,000 Btu/gallon) but is still lower
than petrodiesel (129,00 Btu/gallon).




                                               (continued)
Green Diesel advantages include: (continued)

  All the advantages of biodiesel: As green diesel is
  still derived from vegetable oils, it possesses all
  the environmental and sustainable advantages of
  biodiesel.

  Oil Refinery technology: Hydro-processing
  capacity is already incorporated into most oil
  refineries. This capacity can be leveraged to
  produce large quantities of green diesel in existing
  refineries with only modest modifications.
  Green Diesel disadvantages include:

Experimental: Like so many green technologies,
this process has not been tested on a commercial
scale. Many of the cost and production estimates
are therefore theoretical.

Food vs. Fuel: This process still relies on oils
produced from food stock sources. Large-scale
production again raises the issues associated with
“best-use” concerns for food production and
distribution.
Biomass-to-Liquid advantages include:

Biofuel: As this fuel source is derived from
biomass rather than fossil fuels, it possesses all
the benefits of other biofuel sources (renewable,
low-emissions, etc).

Food vs. Fuel: As the fuel source is cellulosic in
nature, it does not utilize potential food as a
source of energy.
Biomass-to-Liquid disadvantages include:

  Cost: BTL diesel costs about 10% more than
  petrodiesel.

  Lower energy and performance: Energy
  content and performance issues are similar
  to those of other biodiesel fuels.

  Energy intensive: The U.S. Dept of Energy
  has raised concerns that the F-T process is
  quite energy intensive.
Future growth of the biomass fuel industry
(which includes biopower, biofuels and biogas
production) will be dependent upon a number
of factors:
              Technical
              Economic
              Infrastructure
              Resource Limitations
If resource limitations are to be overcome, the
industry must:

      Significantly increase yields from existing
      crops and farmland.

      Find more land to convert to biomass
      production.
      Change the resource required, moving
      from food stock to cellulosic biomass such
      as perennials, waste, woodlands and
      dedicated oilseed crops.
As the biomass energy market expands, changes
within the existing energy infrastructure will be
required.
     Fuel pumps: There are currently only a small
     number of pumps (currently less than 1%) in
     use that are capable of dispensing high
     concentration ethanol biofuel.
     Flex Fuel Vehicles: While a significant number
     of new vehicles are designed to run on fuels
     containing a higher concentration of ethanol,
     they still represent a very small portion of the
     existing vehicle stock.

                                                (continued)
As the biomass energy market expands, changes
within the existing energy infrastructure will be
required. (continued)
     Pipelines: Currently ethanol cannot be shipped
     via existing pipelines. A cost-effective
     distribution system will need to be developed if
     demand is to expand dramatically. Most U.S.
     biodiesel production facilities are located in the
     mid-west (where the grain crops are produced),
     as shown in Figure 4-16. Most demand
     (population centers) is located along the coasts.
Figure 4-16: U.S. Biofuel Production Facilities
The acceptance of any technology is ultimately
governed by economics. These constraints
include:
    Cost of fossil fuels: Low fossil fuel prices have
    limited the expansion of alternative energy in
    recent decades. When fossil fuel prices soar, so
    does interest in biomass fuel. Inconsistent and
    low fossil fuel prices will dampen the expansion
    of biofuels.




                                                (continued)
The acceptance of any technology is ultimately
governed by economics. These constraints
include: (continued)
    Feedstock prices: 57% of the cost of ethanol
    and 78% of the cost of biodiesel production is
    the cost of feedstock. As fuel prices increase,
    so do the costs of energy-intensive feedstock
    (such as corn and soy). The result is that as
    fossil fuel costs rise, the cost of producing
    biofuels also rises. This lowers the economic
    competitiveness of biofuels.


                                               (continued)
The acceptance of any technology is ultimately
governed by economics. These constraints
include: (continued)
     Saturation of co-product markets: The
     economic viability of biofuel production is
     dependent upon the sale of valuable co-
     products (such as glycerine and germ-meal
     animal feed). Large-scale production will
     saturate these specialized markets, lowering
     the price and therefore decreasing the
     profitability of biofuel production.


                                              (continued)
The acceptance of any technology is ultimately
governed by economics. These constraints
include: (continued)
Governmental tax policy: Government has attempted to
encourage the development of biofuels through tax policies
such as tax credits ($0.51/gallon for ethanol, $1.00/gallon
for biodiesel for virgin oil stocks) and import tariffs on
biofuels from other countries (for example, a $0.54/gal
tariff on ethanol imported from Brazil). However, these
policies are often inconsistent and typically short-term in
scope. The lack of a long-term consistent alternative fuels
public policy has tended to constrain biofuel production in
the United States.
Many of the Biomass energy techniques are
still experimental and have not been tested in
commercial conditions. A significant number
of technical barriers still exist:

    Crop yield efficiencies. Growth projections
    assume a tremendous increase in the yield
    per acre of traditional food crops. It is
    unclear, however, how these efficiencies are
    to be achieved.




                                              (continued)
Many of the Biomass energy techniques are
still experimental and have not been tested in
commercial conditions. A significant number
of technical barriers still exist: (continued)

     Cellulosic biofuels: Key to the expansion
     of the biofuels industry is the converting
     of cellulosic plant matter into fuel. These
     processes are still experimental and it is
     unclear if they will provide an
     economically viable method of fuel
     production.


                                                   (continued)
Many of the Biomass energy techniques are
still experimental and have not been tested in
commercial conditions. A significant number
of technical barriers still exist: (continued)

    Refining efficiencies. The refining of fossil
    fuels is a mature and relatively efficient
    industry. Biofuel refining technologies will
    need to be improved if they are to
    compete.




                                               (continued)
Many of the Biomass energy techniques are
still experimental and have not been tested in
commercial conditions. A significant number
of technical barriers still exist: (continued)

   Distribution infrastructure. It remains unclear
   whether the existing fuel infrastructure can
   simply be modified to accept biofuels, or if
   there will be the need for significant investment
   in a new infrastructure to support an emerging
   biofuel supply chain. The answer to this
   question will greatly impact the cost and
   availability of biofuels in the short term.
WARNING

THE WOOD GAS PRODUCTION
PROCESS PRODUCES CARBON
MONOXIDE WHICH CAN BE
FATAL IF INHALED.
Today, wood gas generator systems typically
incorporate four main components:

 1   A wood generator to produce gas from
     solid fuels.
 2   A filter to remove soot and ash from the gas.

 3   A cooling unit to condense tars and other
     impurities from the gas.
 4   A valve to mix the resulting wood gas with
     air, and then direct this mixture into the
     engine’s intake manifold.
Figure 4-17: Imbert Wood Gas Production System
There are three main designs for wood gas
generators, differing primarily on the relative
positions of the air inlet and the gas outlet
(although many variations to these basic
designs exist).

              Updraft generators
              Downdraft generators
              Cross-draft generators
Figure 4-18: Updraft Wood Gas Generator
The advantages of updraft generators include:

   Ease of use: This design is perhaps the simplest
   to construct and operate.
   High efficiency: Higher internal heat leads to a
   more efficient burn process and results in a
   cooler gas leaving the unit.

   Flexible: Many types of biomass can be used
   with this unit.
The disadvantages of updraft generators include:

      Channeling: The top-feeding of biomass can
      lead to the flow of fuel to the burning grate
      being disrupted when some of the material
      forms a bridge (or blockage). This results in
      very high operating temperatures that can
      lead to explosion. For this reason this design
      requires an agitator or some other method to
      shake the material to ensure it flows smoothly
      to the burn area.
Figure 4-19: Downdraft Wood Gas Generator
The advantages of downdraft generators
include:

    Cleaner fuel: This design results in a
    wood gas that contains less impurities.
    This in turn releases fewer potentially
    damaging chemicals into the
    atmosphere.
The disadvantages of downdraft generators
include:

     More ash: While producing a cleaner
     gas, downdraft generators produce
     more waste ash that must be removed
     from the unit.
     Limited fuel sources: This design does
     not work well with lighter density
     biomass. Typically fuels must be
     pelletized when used with this type of
     wood gas generator.
Figure 4-20: Cross-Draft Wood Gas Generator
The advantages of cross-draft generators
include:

     Small Scale: This design is very flexible
     for small applications.
The disadvantages of cross-draft generators
include:

        No Wood: This type of generator
        requires a dry, low tar fuel source
        such as charcoal. Wood and many
        other biomass sources are not
        suitable for this design.
There are significant limitations to the wood gas
system when compared with fossil fuels or other
biofuel sources:
   Less power: Compared with natural gas, wood gas
   contains only about 1/7th the energy by volume
   (150 Btu/cubic foot versus 1,000 Btu/cubic feet).

   Larger storage space: Given its lower energy
   content, wood gas requires seven times the storage
   capacity for the same amount of energy supplied
   by natural gas.



                                               (continued)
There are significant limitations to the wood gas
system when compared with fossil fuels or other
biofuel sources: (continued)
    Weight: When incorporated in a vehicle, the
    considerable weight of a wood gas generator
    (and wood fuel) will dramatically reduce the
    performance of the vehicle.

    Refueling: It takes about 20 minutes to refuel the
    generator (adding biomass, cleaning ash, etc).
    Typically vehicles powered by wood gas must be
    refueled every 125 miles (200 kilometers) or so.
The use of wood gas generators poses a
number of health and safety concerns.
These include:

            Toxic Hazards
            Fire Hazards
            Risk of Explosion
Figure 4-21: Early Pot Still
Figure 4-22: Condensation Points within a Still’s Column
Figure 4-23: Reflux Still
The major parts of the reflux still system
include:

 The Boiler: Basically a stainless steel tank
 (stainless steel will not corrode and does not add
 impurities to the process) in which the fermented
 mash (a mixture of grain or sugar, water and
 yeast) is placed. This mash is then boiled,
 beginning the distillation process.




                                             (continued)
The major parts of the reflux still system
include: (continued)
The Column: Typically columns for small reflux
stills are constructed using copper tubing. They are
typically 2 – 4 feet in length (590 – 1200 mm). To
increase the surface area upon which the vapors
can condense, these columns are typically filled
with small heat-resistant items such as marbles,
glass beads or hollow ceramic cylinders (such as a
product called Raschig Rings). At the top of the
column, a small hole is drilled and a thermometer
attached so that temperature readings can be
monitored at the point furthest from the boiler.
                                             (continued)
The major parts of the reflux still system
include: (continued)
 The Cooling System: Early pot stills utilized a
 coil of tubing to air-cool the vapors. Most
 reflux stills incorporate a water-cooling system
 to assist in lowering the temperatures within
 the column. A simple cooling system circulates
 water around a tube, lowering the temperature
 to the point where ethanol vapor condenses
 into liquid ethanol, as shown in Figure 4-24.
Figure 4-24: Cooling Tube
Fermentation is a series of anaerobic (without
oxygen gas present) processes that break
down sugar (glucose) into alcohol and carbon
dioxide. The resulting chemical equation
(in very basic terms):


  C6H12O6 á 2 CH3CH2OH + 2 CO2
  (glucose)     (alcohol)   (carbon dioxide)
In commercial ethanol production facilities, the
process of unlocking the sugars from the grain
is done in one of two ways:
    Dry Milling: This process is the least expensive
    and produces higher yields of ethanol, but the
    value of the byproducts is considerably less. In
    this process, the grain is cleaned and ground
    into a powder. It is then mixed with water,
    cooked (with added enzymes), fermented and
    then distilled.



                                                 (continued)
In commercial ethanol production facilities, the
process of unlocking the sugars from the grain
is done in one of two ways: (continued)
  Wet Milling: The wet milling process is more elaborate
  and expensive so the grain must be separated into its
  component pieces before undergoing fermentation. The
  grain is heated (for 24-48 hours) in a solution of water
  and sulfur dioxide to loosen the husk and the germ. The
  germ is then removed from the kernel and oil is
  removed. The germ meal is then added to the husk fibers
  to create a high-protein animal feed. Only the starch
  portion of the grain is subjected to fermentation. The oil
  and animal feed byproducts can add considerably to the
  profitability of the production facility.
The distillation of ethanol creates a number of
potential safety hazards:
     Explosion: Alcohol vapors are combustible
     and can explode if they leak from the still and
     come in contact with an open flame or spark.
     The still apparatus should be tested for leaks
     and should always be operated in a well-
     vented location. Electric (rather than gas) heat
     is often incorporated into these systems to
     avoid the potential of escaping gas coming in
     contact with an open flame.



                                                (continued)
The distillation of ethanol creates a number of
potential safety hazards: (continued)
   Fire: There is always a risk of fire when working
   with heat and combustible materials. Alcohol
   vapor as well as liquid ethanol will burn if
   spilled. Extreme caution should be exercised.

   Implosion: The distilling process takes place under
   heat in a sealed container. Once the process is
   complete and the apparatus is allowed to cool,
   a vacuum may develop if air is not allowed to
   enter the still (contracting air within the system
   may implode the boiling tank as illustrated in
   Figure 4-25 as it cools).
Figure 4-25: An Imploding Still
In the making of biodiesel, three products are
used. These include:

      Vegetable oil or animal fats (petroleum
      products such as used motor oil cannot
      be used)
      A catalyst (sodium hydroxide, also
      known as lye)
      Methanol
Creating biodiesel is a fairly simple process. Steps
include:

    1   Heat the oil. If using used oil, it should
        be heated to at least 240°F (116°C) to
        boil off any water that might be
        present. Then let it cool to about 130°F
        (54°C). If new oil is used, preheat the oil
        to 130°F (54°C).




                                                 (continued)
Creating biodiesel is a fairly simple process. Steps
include: (continued)

 2   Mix the NaOH with the Methanol (creating
     methoxide) in a sealed container and allow it
     to mix thoroughly. This is an exothermic
     reaction, so the mixture will generate heat as
     the NaOH dissolves. The mix can be agitated
     (shaken or stirred - speeding up the process).
     It may take as little as 30 minutes or as much
     as 12 hours for the NaOH to completely
     dissolve.


                                                (continued)
    Creating biodiesel is a fairly simple process. Steps
    include: (continued)

      SAFETY WARNING
      DO NOT BREATHE METHANOL OR METHOXIDE FUMES.
      THEY ARE DANGEROUS AND CARTRIDGE RESPIRATORS
      WILL NOT BLOCK METHANOL VAPORS.


3     Once the NaOH is completely dissolved, carefully
      add the methoxide mix to the preheated vegetable
      oil. These should be mixed in a sealed container.

      SAFETY WARNING
      AVOID METHOXIDE SPILLS. THIS MIX IS EXTREMELY
      CAUSTIC TO SKIN AND SURFACES.
 Creating biodiesel is a fairly simple process. Steps
 include: (continued)

Shake or agitate the mixture for about 60 seconds.

After about 10 minutes, the mixture will begin to
separate into two distinct layers. The bottom layer
will be a dark liquid comprised of glycerine (actually
at this point it is about 50% pure glycerine, 40 %
methanol and about 10% soap and catalyst) and a
lighter top layer (about 80% of the mix) of biodiesel.
Let the mix settle completely for 12-24 hours.


                                                 (continued)
Creating biodiesel is a fairly simple process. Steps
include: (continued)

   4   The biodiesel can now be decanted from
       the mix (or the glycerine drained away
       from the bottom).




                                                (continued)
Creating biodiesel is a fairly simple process. Steps
include: (continued)

5   The biodiesel at this point will still contain
    some glycerine, so the fuel will need to be
    washed. This is done by mixing the biodiesel
    with about half its volume of warm water (one
    gallon of biodiesel is mixed with one-half gallon
    of water). After mixing, the water will quickly
    settle out, pulling glycerine with it (during the
    first wash, the water will appear milky in
    color). This process is repeated 3-5 times, each
    time resulting in a more “pure” biodiesel fuel.

                                                (continued)
Creating biodiesel is a fairly simple process. Steps
include: (continued)

  6   Finally the biodiesel will need to “dry”.
      Venting the mix will allow any remaining
      water to evaporate from the mix. When
      the fuel is translucent (no longer cloudy),
      it is ready to be used in any diesel engine.
Figure 4-26: Commercial Cone Bottom Biodiesel
                 Processor
The methanol-ladened glycerine can be:

   Taken to a large biodiesel facility where
   they will (hopefully) dispose of it for a fee.
   Taken to a company that specializes in
   biodiesel waste disposal.
   Taken to a toxic waste dump facility.
   Converted to methane in a biodigestor.
   Mixed with 50% kerosene and used as a
   solvent (makes a great engine cleaner).
Throughout the production of biodiesel process
there are hazards that must be understood and
avoided. These include:

     Caustic Chemicals: The chemicals used as
     catalyst (either lye or potassium oxide-KOH)
     within the reaction are extremely caustic,
     meaning they will burn skin and damage any
     material they come in contact with. Protective
     gloves and eye wear should be worn when
     working with these chemicals.



                                               (continued)
Throughout the production of biodiesel process
there are hazards that must be understood and
avoided. These include: (continued)
  Methanol: Methanol is also caustic in additional to
  being flammable. While it is safer to handle than
  gasoline (according to the U.S. Environmental
  Protection Agency) it can still ignite and its vapors can
  explode if they come in contact with an open flame or
  spark. It is also poisonous if consumed. Again, safety
  equipment should be worn and biodiesel
  manufacturing should take place in a well-ventilated
  area away from ignition sources. Methanol should be
  stored outdoors in sealed and approved containers.

                                                     (continued)
Throughout the production of biodiesel process
there are hazards that must be understood and
avoided. These include: (continued)

     Spontaneous Combustion: Rags and other
     materials often become soaked in biodiesel
     (or the materials used to create biodiesel).
     These can spontaneously combust and
     should be stored in an approved and sealed
     container.
REVIEW QUESTIONS




    1   How does biofuel differ from biomass?
REVIEW QUESTIONS




      2   How does the modification of land
          use affect the carbon cycle?
REVIEW QUESTIONS




  3   List three advantages and three disadvantages
      of utilizing biomass as an energy source.
REVIEW QUESTIONS




     4   List four sources of biomass and the
         advantages and disadvantages of each
         source.
REVIEW QUESTIONS




      5   Define the three major ways that
          biomass is converted into energy.
REVIEW QUESTIONS




      6   Explain two advantages of co-firing
          biomass in traditional fossil fuel
          electrical generating plants.
REVIEW QUESTIONS




  7   Cite three advantages and three disadvantages
      of ethanol as a fuel source.
REVIEW QUESTIONS




   8   Why have advocates of biofuels pinned a
       great deal of hope on the future of cellulosic
       ethanol as compared with ethanol produced
       from grain-based sources?
REVIEW QUESTIONS




   9   Discuss the controversy surrounding the
       energy required to produce ethanol and
       why it is important to the future of ethanol
       production.
REVIEW QUESTIONS




   10 Explain the difference between distillation
       and transesterification and which biofuels
       are created using each process.
REVIEW QUESTIONS




  11 List the limiting constraints (economic,
      technical, infrastructure and resource) on
      the expansion of biofuel as an energy source
      and suggest how these constraints may be
      overcome.
REVIEW QUESTIONS




    12 When has the historic use of wood gas
        generators been widespread and why?
REVIEW QUESTIONS




  13 Discuss how the process of fermentation
      takes place in grain and why it is important
      in the manufacture of ethanol.
REVIEW QUESTIONS




     14 What waste products are created in
         the manufacture of biodiesel and
         how are they best disposed of?
REVIEW QUESTIONS




     15 What are the legal requirements
         involved in small-scale production
         of ethanol and biodiesel?
EXAM QUESTIONS



    1   An advantage of using biomass as an
        energy source is:

        a. it prevents soil erosion.
        b. it allows farmers to produce fuel
           rather than food.
        c. it promotes biodiversity.
        d. it is non-toxic and biodegradable.
EXAM QUESTIONS



    2   Currently the U.S. obtains what percent
        of its energy from biomass sources?

        a. less than 1%
        b. about 3%
        c. just under 12%
        d. more than 25%
EXAM QUESTIONS



 3   Which of the following groups would likely push
     hardest to support legislation supportive of
     biomass as an energy source?

     a. The Farm Bureau
     b. The American Petroleum Institute
     c. The American Association of Retired Persons
     d. The Rainforest Solutions Project
EXAM QUESTIONS



   4   Which of the following is NOT a potential
       source for energy from biomass?

       a. algae
       b. garbage
       c. grass
       d. beef
EXAM QUESTIONS



      5   Converting wood to charcoal is an
          example of:

          a. Pyrolysis
          b. Biodigestion
          c. Co-Firing
          d. Gasification
EXAM QUESTIONS


 6   Which of the following is NOT an advantage of
     using biodiesel to fuel vehicles?

     a. Most newer diesel engines require no
        modifications to run on biodiesel.
     b. Biodiesel burns cleaner than regular diesel fuel.
     c. Biodiesel smells better than regular diesel fuel.
     d. Biodiesel contains more energy than regular
        diesel fuel.
EXAM QUESTIONS



   7   When air passes over a glowing bed of
       embers in a wood gas engine, the following
       gases are produced which can then be
       burned in an internal combustion engine:

       a. Oxygen and Methane
       b. Methane and Helium
       c. Methane and Hydrogen
       d. Hydrogen and Carbon Monoxide
EXAM QUESTIONS



  8   During the fermentation process, which of
      the following is necessary to convert glucose
      to carbon dioxide and alcohol?

      a. temperatures in excess of 77°F/25°C
      b. yeast
      c. oxygen
      d. a reflux still
EXAM QUESTIONS



   9   The process involved in creating biodiesel
       is known as:

       a. distillation
       b. triglyceride
       c. transesterification
       d. biodigestion
EXAM QUESTIONS




  10 Which of the following is NOT a by-product
      of creating biodiesel from vegetable oils?

      a. methanol
      b. glycerine
      c. ethanol
      d. wash-water

								
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