Sustainable Energy Technologies
MSE0290
5. Biomass
Eduard Latõšov
Contents
Nature of biomass
Resources
Utilisation
Technologies
Planning
Summary
Nature of biomass
Nature of biomass
Biomass, mainly in the form of wood, is the oldest form of
energy used by humans.
Traditionally, biomass has been utilized through direct
combustion, and this process is still widely used in many parts of
the world.
Read more: Biomass resource facilities and biomass conversion processing for fuels and
chemicals, Ayhan Demirbaş, Energy Conversion and Management
Volume 42, Issue 11, July 2001, Pages 1357–1378
Source: http://www.heatilator.com/Shopping-Tools/Blog/How-to-Buy-a-WoodFireplace-Part-1-of-2.aspx
Nature of biomass
Source: http://eng.marmore.com.tr/what-is-renewable-energy-and-biomass-
Traditionally, direct combustion. Now….
Nature of biomass
Source: https://www.iea.org/publications/freepublications/publication/2012_Bioenergy_Roadmap_2nd_Edition_WEB.pdf
Traditionally, direct combustion. Now….
Nature of biomass
Nature of biomass
Classification
Nature of biomass
Classification
Manual for biofuel users
Author: Villu Vares, Ülo Kask, Peeter Muiste, Tõnu Pihu, Sulev Soosaar, Tallinna Tehnikaülikool,
Author of foreword: Gudrun Knutsson
Nature of biomass
Classification
Manual for biofuel users
Author: Villu Vares, Ülo Kask, Peeter Muiste, Tõnu Pihu, Sulev Soosaar, Tallinna Tehnikaülikool,
Author of foreword: Gudrun Knutsson
Nature of biomass
Sustainable?/!
Nature of biomass
Sustainable?/!
The critical difference between biomass fuels and fossil
fuel, is that of fossil and contemporary carbon.
Burning fossil fuels results in converting stable carbon
sequestered millions of years ago into atmospheric
carbon dioxide (when the global environment has
adapted to current levels).
Burning biomass fuels however, returns to the
atmosphere contemporary carbon recently taken
up by the growing plant, and currently being taken
up by replacement growth.
Source: http://www.biomassenergycentre.org.uk/portal/page?_pageid=76,535178&_dad=portal&_schema=PORTAL
Nature of biomass
Sustainable?/!
Source: https://www.iea.org/publications/freepublications/publication/2012_Bioenergy_Roadmap_2nd_Edition_WEB.pdf
Nature of biomass
Sustainable?/!
Nature of biomass
Sustainable?/!
Nature of biomass
Properties
Nature of biomass
Properties
Components of solid fuel
Nature of biomass
Properties
Components of solid fuel
As the moisture content of fuel
varies a lot, in reference tables
the content of ash and volatiles
is given on dry matter basis.
The following relationship is valid between
the ash content in the dry matter and that in
the as-received fuel:
A = Aar x 100/(100 – Mar),
where A is the ash content and M the
moisture content.
Nature of biomass
Properties
Calorific value
The calorific value is usually expressed in MJ/kg or kJ/kg
The net (lower) versus gross (higher) calorific values
The higher calorific value is calculated assuming that the
water vapour in flue gas both from the fuel moisture
content and as a combustion product of hydrogen has
completely condensed.
The condensation heat of water vapour in flue gases is
not taken into account for calculation of the lower
calorific value.
The higher the moisture content and hydrogen content
are, the bigger is the difference between the gross (higher)
and net (lower) calorific values.
Nature of biomass
Properties
Calorific value
Mostly, the flue gas is discharged from the
boiler to the stack at the temperature of over
100 °C, i.e., at the temperature much higher
than the dew-point and under such conditions
the condensation energy of water vapour
remains unused.
Nature of biomass
Properties
Calorific value
Nature of biomass
Properties
Calorific value
The calorific value can be either that of a
moist (ar),
dry (d) or
dry ash-free (daf) fuel.
The calculation formulae for the net (lower)
and gross (higher) calorific values are (Hd
– hydrogen content by the weight % in dry
fuel; calorific value in MJ/kg):
Nature of biomass
Fusibility of ash
1 – the initial state: before heating the peak
of ash cone is sharp;
IT – initial point of deformation: the sharp
peak is rounding;
beginning of deformation (initial
temperature) IT = 1150 – 1490 °C;
ST – softening temperature, the ash cone
deforms to such extent that the height of
the structure reduces to the size of its
diameter (H = B);
softening temperature
ST = 1180 – 1525 °C;
HT – the point of formation of hemisphere
or, the cone collapses and becomes domeshaped (H = 1/2·B);
the point of hemisphere formation
HT = 1230 – 1650 °C;
FT – flow temperature, the liquid ash
dissipates along the surface.
flow temperature FT = 1250 – 1650 °C.
Nature of biomass
Fusibility of ash
SLUGGING
PROBLEMS
Resources
The global distribution of photosynthesis, including both
oceanic phytoplankton and terrestrial vegetation. Dark red
and blue-green indicate regions of high photosynthetic
activity in ocean and land respectively.
Resources
Resources
The earth's natural biomass replacement represents an
energy supply of around 3 000 EJ (3×1021 J) a year, of
which just under 2% in 1998 was used as fuel. It is not
possible, however, to use all of the annual production of
biomass in a sustainable manner.
One analysis provided by the United Nations Conference
on Environment and Development (UNCED) estimates that
biomass could potentially supply about half of the present
world primary energy consumption by the year 2050.
Source: Ramage J, Scurlock J. Biomass. Renewable energy-power for a sustainable future. In:
Boyle G, editor. Oxford: Oxford University Press; 1996
Utilisation
Utilisation
TOTAL
Comparison of primary bioenergy demand in this roadmap and
global technical bioenergy potential estimate in 2050
Source: https://www.iea.org/publications/freepublications/publication/2012_Bioenergy_Roadmap_2nd_Edition_WEB.pdf
Utilisation
Bioenergy for Heat and Power
Utilisation
Bioenergy for Heat and Power
Utilisation
Bioenergy for Heat and Power
Organisation for Economic Co-operation and Development
List available here:
http://www.oecd.org/about/membersandpartners/list-oecd-member-countries.htm
Utilisation
Bioenergy for Heat and Power
Roadmap vision of world final bioenergy
consumption in different sectors
Utilisation
Bioenergy for Heat and Power
Utilisation
Bioenergy for Heat and Power
CO2 emission reductions from bioenergy electricity
and bioenergy use in industry and buildings compared to
a business as usual scenario (6°C Scenario)
Cumulative technology contributions to
power sector emission reductions in ETP
2014 hi-Ren Scenario, relative to 6DS, up
to 2050
Utilisation
Utilisation
Biofuels for Transport
Utilisation
Biofuels for Transport
Utilisation
Biofuels for Transport
Technologies
Technologies
Technologies
Technologies
… different technologies.
Focus on direct burning.
Technologies
Rankine cycle
Boiling point 100oC pressure
760 mmHg = 0,101 MPa
Steam
Boiling – without temperature increase
Liquid
evaporation
You 2260 kJ/kg to evaporate 1 kg of H2O at 100oC
Technologies
Rankine cycle
Blue area – heat losses in condenser, red area – useful energy of turbine.
Goal – increase red area. How?
1). Decrease condensing process (4-5) temperature (lowering the condenser
pressure).
2). Increase vaporization temperature (depends on pressure). Process (1-2).
3). Increase steam superheating temperature. Superheating process (2-3).
http://www.gunt.de
Planning
Overview of bioenergy power plant
conversion efficiencies and cost
components
Planning
Capital and O&M costs
Overview of possible operating parameters and generating costs
for bioenergy electricity by 2030
Planning
CHP
HEAT
ONLY
CHP versus HEAT ONLY
Planning
LCOE
Bioenergy electricity generation costs 2010 and 2030,
compared to coal and natural gas based power generation
Liquid fuels
Summary
Disadvantages
Cons
Energy intensive to produce. In some cases, with little or no net gain.
Land utilization can be considerable. Can lead to deforestation.
Requires water to grow
Not totally clean when burned (NOx, soot, ash, CO, CO2)
May compete directly with food production (e.g. corn, soy)
Some fuels are seasonal
Heavy feedstocks require energy to transport.
Overall process can be expensive
Some methane and CO2 are emitted during production
Not easily scalable
Summary
Advantages
Pros
Truly a renewable fuel
Widely available and naturally distributed
Generally low cost inputs
Abundant supply
Can be domestically produced for energy independence
Low carbon, cleaner than fossil fuels
Can convert waste into energy, helping to deal with waste
Any questions?