Transcript Document

Biochar Basics:
An Introduction about the
What and Why of Biochar
Version 1 of these slides was presented at the
2009 Northeast Biochar Symposium, November 13 at
the University of Massachusetts Amherst
(Released for general distribution and use by others.)
Paul S. Anderson, PhD
Hugh McLaughlin, PhD, PE
AKA “Dr. TLUD” (TEE-lud)
V.P. of Chip Energy Inc
Specialist in micro-gasification
[email protected]
Director of Biocarbon Research
Alterna
Biocarbon Inc.
[email protected]
Slide-set modified and presented by:
(Add presenter’s identification)
Biochar Defined:
• The placement of charcoal into soils.
• The presence of nearly pure carbon in
soils, in the form of amorphous graphite.
• NOT carbon that is in living organisms.
• NOT fossil carbon, as in coal, oil, or
natural gas.
His ancestors
accomplished
soil
improvements
that modern
science is
trying to
understand
and replicate.
Latosol vs. Terra Preta (Dark Earth)
Terra preta is excellent soil with high presence of charcoal (biochar).
Terra preta might be from “slash and char” practices, but
NOT from current “slash-and-burn” agricultural practices.
Summary of Biochar Properties
• Was biomass; now has charcoal-like properties.
• Significant carbon content, but more than just
carbon that has been sequestered:
• Internal surface area and adsorption properties.
• CEC = cation exchange capacity, better
fertilizer retention and less field runoff.
•Significant synergisms with soil microbes over
time – nitrogen fixers and other good “bugs.”
Half-life of biochar
is ~1400 years.
Conclusion # 1:
• There is something about abundant charcoal in
soils that can be highly beneficial to plants.
• The benefits last for at least hundreds of years.
• Biochar has potential for improving soils and
feeding people, especially where soils are weak.
• ONLY possible with charcoal:
– NOT by putting coal dust into soils.
– NOT by adding manure or other organic
material.
Basic Forms and
Transformations of Carbon:
Elemental Carbon
C
(solid)
Activated charcoal
Regular charcoal
Graphite
Carbon black (soot)
Coke (from coal)
Oxide gases
C+O
CO & CO2
Biomolecules
Hydrocarbons
C+H
Coal, oil, gases
C+H+O
Carbohydrates,
Sugars, Cellulose,
Lignin, & much
more in living and
dead biomass.
Basic Forms and
Transformations of Carbon:
Elemental Carbon
C
(solid)
Activated charcoal
Regular charcoal
Graphite
Carbon black (soot)
Coke (from coal)
Hydrocarbons
C+H
Coal, oil, gases
Add Oxygen:
Oxide gases
Gasification &
combustion
CO & CO2
C+O
Add Oxygen: Add H O and
2
Decay
Carbonization /
Pyrolysis:
Create charcoal
& liberate gases
Loose Oxygen:
Become fossil fuels
photosynthesis by
plants
Biomolecules
C+H+O
Carbohydrates,
Sugars, Cellulose,
Lignin, & much
more in living and
dead biomass.
From: http://www.techtp.com/Torrefaction%20for%20High%20Quality%20Wood%20Pellets.pdf, page 7 of 36
How does wood burn?
• Wood, consists of hemicellulose, cellulose
and lignin
–
–
–
–
Hemicellulose gasifies at 250 – 300C
Cellulose splits into char and volatiles between 300C and 450C
Lignin splits into char and volatiles between 300C and 750C
Volatilization cools the remaining solid, but the gases burn and
generate radiant heat (yellow to blue light)
– Eventually, oxygen can react with the remaining char to make
CO2, H2O and ash, plus more heat (red light)
• Putting it all together, we can summarize
this in the next two slides that are easier
to understand:
Pyrolysis & Carbonization Reactions of Wood
Below 288 C = Torrefied Wood
Hemicellulose
Lignin
Cellulose
Extensive
Devolatilisation
and
E
E
carbonisation
(E)
D
D
D
Limited
devolatilisation
and
carbonisation (D)
250
C
200
200
C
150
depolymerisation
and
recondensation
(C)
150
glass transition/
softening (B)
drying (A)
A
A
100
100
Hemicellulose
Lignin
Cellulose
Temperature (°C)
Temperature (°C)
250
300
TORREFACTION
300
Above 325 C = Biochar
A match shows the simple
production of charcoal
The combustion flame (“C”) burns gases and provides heat to sustain
pyrolysis (“P”). Ash is held in the charcoal until “G” (char-gasification)
releases it. When “C” goes out, visible smoke shows condensing gases.
Making charcoal
•
•
•
•
•
the first synthetic material produced by man.
used to draw on the walls of caves, and
used to transport fire (embers) to new locations.
later used for smelting tin to make bronze tools.
easier to do than any of the coal – oil – gas
options:
– Converting wood to charcoal is done by heating in an
atmosphere of limited oxygen.
– Known as “Pryolysis” or “Carbonization”, we do it
every time we make a fire with wood.
– And Mother Nature’s forest fires predate Smoky the
Bear ……
Chemical changes as wood becomes biochar:
Created by photosynthesis using
solar energy + CO2 + H2O
(35 wt %)
57% of carbon
(40 wt %)
0%
+
6% + 4% of carbon
(25 wt %)
33% of
carbon
Charcoal retains ~ 20% of the weight and 30% of the energy of
the biomass, so ~70% of the energy is released as usable vapors.
W
oo
W dP
oo el
l
To d C et s
G
rr hi - A
ra
ef p
ss
ie s G P
d B
ra e
F
ss lle
ir
P tC
-C
el h
le a
S tC r#
tra h 1
S w ar # - D
tra C 2
h
S w C ar - E
tra h #
w ar 1 C # F
ha 2
G
r# -G
as
3
G ifie
-H
as r
ifi Ch
er a
C r#
W
ha 1
M ood
r# -I
ac P
2
-J
N el
B ut let
io S C
ch h h
ar ell ar
Ju
B Ch - K
ni
ra a
pe
nd r rB
#1 L
A io
sp c
M
en arb
Ju C B o
ni ed io n #
Ju pe ar car 1 ni r B Bio bo N
pe io c n
r B ca arb - O
io rbo on
c n Fi arb # P
rB o 2
io n # - Q
ca 3
rb - R
on
-S
Weight percent of dry sample
MODIFIED ULIMATE ANALYSES OF CHARS
100%
80%
60%
40%
20%
0%
Res ident Carbon
Res ident H & O
Res ident Nitrogen
Mobile Carbon
Mobile H & O
Mobile Nitrogen
As h (acid s oluble)
As h (non-s oluble)
Source: McLaughlin, Anderson, Shields & Reed (2009). All Biochars Are Not Created Equal…terrapreta.bioenergylists.org
Conclusion # 2:
• Charcoal is made by the thermal
transformation of biological matter,
mainly carbohydrates.
• Plant biomass seems to create the best
biochar – both woods and grasses.
• All biochars are not equal – both starting
biomass and carbonization conditions
influence the final biochar properties.
Basic Forms and
Transformations of Carbon:
Elemental Carbon
C
(solid)
Activated charcoal
Regular charcoal
Graphite
Carbon black (soot)
Coke (from coal)
Hydrocarbons
C+H
Coal, oil, gases
Add Oxygen:
Oxide gases
Gasification &
combustion
CO & CO2
C+O
Add Oxygen: Add H O and
2
Decay
Carbonization /
Pyrolysis:
Create charcoal
& liberate gases
Loose Oxygen:
Become fossil fuels
photosynthesis by
plants
Biomolecules
C+H+O
Carbohydrates,
Sugars, Cellulose,
Lignin, & much
more in living and
dead biomass.
Timelines for Carbon
Transformations & Permanence
Burn it.
Burn it.
CO2
200+ years of fossil
fuel consumption is
Carbon Positive:
C+
Biomass
Natural short-term
cycle of growth and
decay (including
biomass burning) is
Carbon Neutral: C=
(living and dead)
100 million
years ( C- )
Fossil Fuels
Storing carbon is
Carbon Negative: C-
Biochar in Soils
100 minutes ( C- )
Biocarbon
Optional human activity,
creating Terra Preta
Hundreds or thousands of years
as long-term carbon sequestration: C-
Timelines for Carbon
Transformations & Permanence
Burn it.
Burn it.
CO2
200+ years of fossil
fuel consumption is
Carbon Positive:
C+
in enormous Biomass
(living and dead)
proportions!!!
100 million
years ( C- )
Fossil Fuels
Natural short-term
cycle of growth and
decay (including
biomass burning) is
Carbon Neutral: C=
Storing carbon is
Carbon Negative: C-
Biochar in Soils
100 minutes ( C- )
Biocarbon
Optional human activity,
creating Terra Preta!!!
Hundreds or thousands of years as
long-term carbon sequestration:
C-
285 in 1950
Ice age
Ice age
Ice age
Ice age
> 380
in 2010
< 300
in 1950
Most recent Ice Age
Shows ONLY 400,000 years. “Civilization” is less than 10,000 years old.
Global Temperature and Atmospheric CO2 over Geologic Time
Today
Late Carboniferous to Early Permian time (315 mya -- 270 mya) is the only time period
in the last 600 million years when both atmospheric CO2 and temperatures were as low
as they are today (Quaternary Period ).
Temperature after C.R. Scotese http://www.scotese.com/climate.htm
Source:
CO2 after R.A. Berner, 2001 (GEOCARB III)
http://www.geocraft.com/WVFossils/Carboniferous_climate.html
Conclusion # 3:
• Global warming can be debated, but the increase in
atmospheric CO2 levels is clearly measured and due
to human activities.
• The Earth is very capable of existing with much
higher CO2 levels, but our current human society
probably could not.
• The only current reasonable method for human
action to remove significant amounts of atmospheric
CO2 is through biochar for carbon sequestration.
• And Conclusion # 1 states that Biochar is being
shown to improve poor soils, so put char into soils!
Potential Sources of Biochar
Chart of Potential Sources of Biochar
Source: McLaughlin, Anderson, Shields & Reed (2009). All Biochars Are Not Created Equal…terrapreta.bioenergylists.org
Type =>
Issue
Incidental
Traditional
Application
Fire
Residual
Lump
Charcoal
Biomass to
Energy
By or Coproduct
Sole
product
Description
(Highly
generalized)
Fireplace
Forest fire
Incineration
Primitive kilns
Downdraft
Updraft
Top-Lit UpDraft
Traditional retort
Specialized retort
Fast Pyrolysis
Biocarbon for energy
Biochar for soil
Bio-Gas & Bio-Oil
Oxygen?
Oxic - Uncontrolled
Oxic = limited
oxygen and
Anoxic = no oxygen
Oxic
Anoxic (usually)
Anoxic and Oxic
Commercial
for biochar?
No. Basically
destructive.
Yes. Established
product – for cooking
Biochar is NOT the
primary objective.
Initial efforts & biochar is
NOT the primary goal
Initial efforts
Modern
kilns
Gasifier
Other Modern Industrial Processes
(TLUD)
End of the Beginning about Biochar Basics
• Further discussions can cover issues of:
– Production of biochar, including cook stoves.
– Application of biochar.
– Impact of biochar on plants and soil microbes.
Or is this the Beginning of the End?
• With the rising CO2 level, living conditions of most
of humanity will be affected, and current cultural
structure and political stability are unlikely to
continue for another 100 years.
• Issues of atmospheric CO2 concentrations will not
be resolved without conscious and significant
actions by all the fuel-intense nations of the World
– and actions on the ground everywhere.