CONVERSION OF BIOMASS TO BIOFUELS
WSU ChE 481/581 & UI BAE 504
THERMOCHEMICAL CONVERSION SECTION
LECTURER: MANUEL GARCIA-PEREZ , Ph.D.
Department of Biological Systems Engineering
205 L.J. Smith Hall, Phone number: 509-335-7758
e-mail: mgarcia-perez@wsu.edu
CREDIT HOURS: 3
MEEETING PLACE: EME B46, TUESDAY AND
THURSDAY 1:25-2:40 AM
OUTLINE OF OUR PREVIOUS LECTURE
THERMOCHEMICAL
REACTIONS
INTRODUCTION
A.- OVERVIEW
B.- BIOMASS RESOURCES (UNIQUE ROLE OF BIOMASS)
C.- CONVERSION TECHNOLOGIES
D.- INTRODUCTION TO THERMOCHEMICAL CONVERSION
TECHNOLOGIES
E.- CELLULOSE PRIMARY THERMOCHEMICAL REACTIONS
F.- EFFECT OF ALKALINES, ACID AND OXYGEN
G.- INTERACTIONS BETWEEN THE CELLULOSE AND THE LIGNIN
H.- SECONDARY THERMOCHEMICAL REACTIONS
I.- CONCLUDING REMARKS
OVERVIEW OF THE THERMOCHEMICAL SECTION
LECTURE 1
INTRODUCTION TO BIOMASS THERMOCHEMICAL CONVERSION
TECHNOLOGIES AND THERMO-CHEMICAL REACTIONS
LECTURE 2
TORREFACTION AND PYROLYSIS (SLOW AND FAST)
LECTURE 3
GASIFICATION, COMBUSTION AND HYDROTHERMAL CONVERSION
LECTURE 4
CHARACTERIZATION AND USES OF THERMOCHEMICAL REACTION PRODUCTS
SECOND LECTURE OUTLINE
A.- TORREFACTION
B.- SLOW PYROLYSIS (CARBONIZATION)
C.- FAST PYROLYSIS
D.- CONCLUSION
A.-TORREFACTION (225-300 oC)
TORREFACTION IS NOT YET COMMERCIALLY AVAILABLE
TORREFACTION IS A THERMAL TREATMENT STEP IN THE RELATIVELY LOW TEMPERATURE RANGE
OF 225 – 300 oC. THE AIM IS TO PRODUCE A FUEL WITH INCREASED ENERGY DENSITY BY
DECOMPOSING THE REACTIVE HEMICELLULOSE. TORREFACTION ALSO INDUCES LARGE
MODIFICATIONS IN THE STRUCTURE OF CELLULOSE AND LIGNIN. TORREFIED BIOMASS HAS
LOWER MOISTURE CONTENT AND HIGHER CALORIFIC VALUE. TORREFIED BIOMASS CONTAINS
70 % OF ITS INITIAL WEIGHT AND 90 % OF THE ENERGY CONTENT. THE MOISTURE UP-TAKE OF
TORREFIED BIOMASS IS VERY LIMITED FROM 1 TO 6 %.
TORREFACTED BIOMASS HAS SEVERAL ADVANTAGES
PRIOR
TO
GASIFICATION,
ELECTRICITY
CONSUMPTION
FOR
MILLING
DECREASES
SIGNIFICANTLY. THE FIBROUS STRUCTURE AND THE
TENACY OF BIOMASS ARE REDUCED BY
HEMICELLULOSE DECOMPOSITION TOGETHER WITH
THE DEPOLYMERIZATION OF CELLULOSE DURING THE
TORREFACTION
REACTION.
THE
POWER
CONSUMPTION IN SIZE REDUCTION IS DECREASED 85
% WHEN THE BIOMASS IS FIRST TORREFACTED.
MOREOVER, THE CAPACITY OF THE MILL INCREASES
IN PROPORTION TO THE PARTICLE SIZE. WHEN THE
0.2 mm PARTICLE SIZE IS CONSIDERED, THE CHIPPER
CAPACITY FOR TORREFIED WILLOW IS UP TO 6.5
TIMES THE CAPACITY OF UNTREATED WILLOW.
AIR
UTILITY FUEL
FLUE GAS
TORREFACTION
GASES
BIOMASS
Combustion
TORREFIED
BIOMASS
Drying
FLUE GAS
Torrefaction
Heat
exchange
Cooling
FLUE GAS
GENERAL FLOW DIAGRAM OF A TORREFACTION PROCESS
A.-TORREFACTION (225-300 oC)
HIGH TEMPERATURE REACTIONS (320 – 600 oC)
MAIN REACTIONS HAPPENING DURING BIOMASS TORREFACTION
CELLOTRIOSAN
CELLOBIOSAN
LEVOGLUCOSAN
Depolymerization
2
CO2, H2O, CO, FORMIC
ACID, ACETIC ACID,
GLYOXAL, ACETOL, METHYL
GLYOXAL
HAA
Fragmentation
3
Fragmentation
3’
CELLULOSE
1
4
Depolymerization
and
Fragmentation
6
Intermolecular
dehydratation
290 oC
CRYSTALLINE
CELLULOSE OF LOW DP
(200-400)
(ACTIVE CELLULOSE)
CROSS LINKED
DIMER, ....
MOLTEN CELLULOSE
(INTERMEDIARY
CELLULOSE)
5
Polycondensation
CROSSLINKED
CELLULOSE +
H2O
7
CHARCOAL
+ CO + CO2
MAIN TORREFACTION REACTIONS
LOW TEMPERATURE REACTIONS (180-320 oC)
Varhegyi G, Jakab E: Is the Broido-Shafizadeh Model for Cellulose Pyrolysis True? Energy & Fuels 1994, 8, 1345-1352
Haas T.J., Nimlos M.R., Donohoe B.S.: Real-Time and Post-reaction Microscopic Structural Analysis of Biomass Undergoing Pyrolysis. Energy & Fuels
2009, 23, 3810-3817.
A.-TORREFACTION (225-300 oC)
Volatiles
(0.128 kg, 632 kJ)
TORREFACTION REACTOR
(250 oC, 30 min)
AIR
Torrefied Wood
(0.872 kg, 17085 kJ)
Heat
(87 kJ)
TORREFACTION REACTOR
(300 oC, 10 min)
FLUE GAS
TORREFACTION
GASES
21.4
Volatiles
(0.332 kg, 3541 kJ)
Wood
(1 kg, 17630 kJ)
0
BIOMASS
156.1
134.7
Drying
22.2
Torrefied Wood
(0.668 kg, 14213 kJ)
FLUE GAS
142.2
Wood
(1 kg, 17630 kJ)
Combustion
7.97
14.7
1.7
27.7
Torrefaction
Cooling
135.6
5.5
Heat
exchange
4.1
FLUE GAS
Heat
(124 kJ)
OVERALL MASS AND ENERGY BALANCES FOR
TORREFACTION AT TWO DIFFERENT TEMPERATURES
NET ENERGY FLOWS (IN MW) CORRESPONDING WITH
TORREFACTION OF WOODCUTTINGS AT 280 oC .
DURING TORREFACTION, BIOMASS LOSES RELATIVELY MORE OXYGEN AND HYDROGEN COMPARED TO CARBON.
SUBSEQUENTLY, THE CALORIFIC VALUE OF PRODUCTS INCREASES. THE NET CALORIFIC VALUE OF TORREFIED
BIOMASS IS ON THE RANGE OF 18-23 MJ/KG (LHV) OR 20-24 MJ/KG (HHV). THE TORREFIED BIOMASS ALSO
BECOMES MORE POROUS WITH THE VOLUMETRIC DENSITY OF 180-300 KG/M3.
A.- TORREFACTION (200-300 oC)
COMPOSITION OF WOOD AND TORREFIED WOOD (WILLOW)
WOOD
Carbon
Hydrogen
Oxygen
Nitrogen
Ash
LHV (MJ/kg)
47.2 %
6.1 %
45.1 %
0.3 %
1.3 %
17.6
TORREFIED WOOD
(250 oC, 30 min)
51.3 %
5.9 %
40.9 %
0.4 %
1.5 %
19.4
TORREFIED WOOD
(300 oC, 10 min)
55.8 %
5.6 %
36.2 %
0.5 %
1.9 %
21.0
THE NET EFFICIENCY OF TORREFACTION IS AROUND 91 % WHEN THE UTILITY
CONSUMPTION IS INCLUDED. THE MASS YIELD OF THE TORREFACTION PROCESS
IS AROUND 70 %
B.- SLOW PYROLYSIS (350-600 oC)
THE HISTORICAL DEVELOPMENT OF PYROLYSIS RELATED INDUSTRIES IS ONE OF THE
MOST INTERESTING IN THE ANNALS OF INDUSTRIAL CHEMISTRY. VERY OFTEN THE
BY-PRODUCT OF TODAY BECOMES THE MAIN PRODUCT OF TOMORROW.
JAMES WITHROW, 19151
SINCE THE CHEMICAL INDUSTRY TODAY CAN PRODUCE THE BY-PRODUCTS OBTAINED
FROM THE PYROLYSIS OF WOOD, WITH THE EXCEPTION OF CHARCOAL, MORE
CHEAPLY THAN THE PYROLYSIS PROCESS, THE MAIN EMPHASIS IN THE LATTER IS ON
THE PRODUCTION OF CHARCOAL. FOR THIS REASON SIMPLE CARBONIZATION
METHODS, SIMILAR TO THE ORIGINAL CHARCOAL PILES BUT IN AN IMPROVED FORM
ARE LIKELY TO BE MORE ECONOMICAL THAN MORE COMPLICATED PLANTS THAT
PLACE EMPHASIS ON THE ISOLATION AND PROCESSING OF BY-PRODUCTS.
HERMAN F.J. WENZL, 19702,3
1James,
2Wenzl
3Antal
R, Withrow: The Chemical Engineering of the Hardwood Distillation Industry. Ind. Eng. Chem. Res. Vol. 7, No. II, p. 912 (1915)
H.F.J. The Chemical Technology of Wood, Academic Press, 1923.
MJ, Gronli M: The Art, Science and Technology of Charcoal Production. Ind. Eng. Chem. Res. 2003, 42, 1619-1640.
B.- SLOW PYROLYSIS (350-600 oC)
CELLULOSE PRIMARY THERMOCHEMICAL REACTIONS
CO2
O
(II) HIGH TEMPERATURE
REACTIONS (300-600 oC)
CO
O
H2 O
Oligo-sugars
CHAR
(Polyaromatics)
CH4
OH
OH
HO
O H
OH
H
HO
O
H
O
H
H
HO
H2 O
H
CH4
HO
O
4
Cellulose
5
H2
6
FAST PYROLYSIS
1
CO
Cellulose of
Low DP (Active
Cellulose)
2
Molten
Cellulose
3
Cross-linked
+ H2 O
Cellulose
SLOW PYROLYSIS
(I) LOW TEMPERATURE REACTIONS (180-300 oC)
(PRE-TREATMENT)
B.- SLOW PYROLYSIS (350-600 oC)
SLOW PYROLYSIS AND PRODUCTION OF CHARCOAL
SLOW PYROLYSIS: BIOMASS IS PYROLYSED AT SLOW HEATING RATES (5-100 oC/MIN). THIS
LEADS TO LESS LIQUID AND MORE CHAR PRODUCTION.
USERS PREFER CHARCOAL OVER OTHER BIOMASS FUELS SUCH AS WOOD. CHARCOAL HAS A
HIGHER ENERGY DENSITY THAN OTHER BIOMASS FUELS AND CAN BE STORED WITHOUT FEAR
OF INSECT PROBLEMS. CHARCOAL IS ALSO DESIRED FOR THE FLAVORS WHICH IT IMPACTS TO
GRILLED FOOD. AS USERS BECOME MORE AFFLUENT, THEY TYPICALLY SWITCH FROM WOOD
FUELS TO CHARCOAL AND THEN TO PETROLEUM FUELS SUCH AS KEROSENE OR LPG.
THE FOOD AND AGRICULTURE ORGANIZATION (FAO) HAS ESTIMATED THAT TOTAL CHARCOAL
PRODUCTION IS AROUND 24 MILLION TONNES . ABOUT HALF OF THE WORLD CHARCOAL USE
IS IN AFRICA, WHERE TRADITIONAL PRODUCTION TECHNIQUES LEAD TO A LOW CONVERSION
EFFICIENCY (23 %). IT MEANS THAT 100 MILLION TONNES OF WOOD ARE ANNUALLY CUT FOR
CHARCOAL PRODUCTION.
THE FACT THAT CHARCOAL CONSUMPTION IS DOMINATED BY URBAN USERS FUELS THE
ACCUSATION THAT RURAL AREAS SUBSIDIZE AND BEAR THE BURNT OF URBAN ENERGY USE, AS
THE SUPPLIES TAKEN FROM RURAL AREAS DIRECTLY AFFECT LOCAL AVAILABILITY OF
WOODFUELS. THE IMPACT OF CHARCOAL PRODUCTION ON FOREST IS LARGE FOR TWO
REASONS: (1) THE WOODFUEL EQUIVALENT IS 4-6 TIMES LARGER, DUE TO THE INEFFICIENCY OF
THE PRODUCTION PROCESS. (2) THE PRODUCTION OF CHARCOAL IS CONCENTRATED IN SMALL
AREAS OVER A SHORT PERIOD OF TIME.
B.- SLOW PYROLYSIS (350-600 oC)
EVOLUTION OF PYROLYSIS RESEARCH
ANCIENT TIMES
THE RELATIONSHIP BETWEEN HUMANKIND AND FIRE HAS BEEN
DOCUMENTED IN THE MUTH OF PROMETHEUS, WHO STOLE FIRE FROM THE
GODS TO GIVE IT TO MAN.
MAGNIFICENT CHARCOAL DRAWING IN
THE GROTTE CHAUVET (OVER 38,000
YEARS OLD) SUGGEST THAT CHARCOAL
WAS THE FIRST SYNTHETIC MATERIAL
PRODUCED MY MAN. SHALLOW PITS OF
CHARCOAL WERE NEEDED TO MELT TIN
FOR THE MANUFACTURE OF BRONZE
TOOLS1.
ANCIENT WORLD PRODUCED CHARCOAL AND MASTERED THE RECOVERY OF
DISTILLATION PRODUCTS. MACEDONIANS PRACTICED CHARCOAL BURNING IN
PITS FOR THE PURPOSE OF OBTAINING TARS. CHARCOAL BURNING IS AS OLD
AS THE USE OF METALS.
Antal MJ, Gronli M: The Art, Science and Technology of Charcoal Production. Ind. Eng. Chem. Res. 2003, 42, 1619-1640.
B.- SLOW PYROLYSIS (350-600 oC)
EVOLUTION OF PYROLYSIS RESEARCH
WITHOUT TAR RECOVERY
Early charcoal production in earth kilns
WITH TAR RECOVERY
B.- SLOW PYROLYSIS (350-600 oC)
WOOD DISTILLATION INDUSTRIES1
1658 - GLAUBER IDENTIFIED THE PYROLIGNEOUS ACID WITH THE ACID CONTAINED IN
VINAGER.
1661 - BOYLE DESCRIBED THE SEPARATION OF A SPIRITUOUS LIQUID FROM THE VOLATILE
PRODUCT OF WOOD DISTILLATION
1792 - ILLUMINATING GAS MANUFACTURED FROM WOOD WAS COMMERCIALIZED IN
ENGLAND.
1819 - REICHNBACH DESIGNED THE FIRST OVEN IN WHICH THE HEAT REQUIRED FOR
INITIATING AND CARRYING OUT THE PROCESS WAS TRANSFERRED THROUGH METAL
WALLS.
1856 - SR. WILLIAM H PERKIN PATENTED ANILINE PURPLE INCREASING THE DEMAND
FOR METHYL ALCOHOL.
1864 - INCREASE IN DEMAND OF WOOD SPIRITS DUE TO THE DISCOVERY OF IODINE.
1870 - CHEMICALLY PURE ACETIC ACID WAS OBTAINED AS A RESULT OF THE EARLY
INVESTIGATION OF LOWITZ.
1870 - INCREASE IN THE DEMAND OF ACETONE DUE TO RISE OF THE CELLULOID
INDUSTRY AND THE MANUFACTURE OF SMOKELEESS POWDER.
1 Klar
M, Rule A: The technology of Wood Distillation. Chapman & Hall, LTD, 1925
B.- SLOW PYROLYSIS (350-600 oC)
Hardwood by product recovery plant including carbonization and refining factories to produce acetic acid, methanol and
charcoal
BIO-OIL REFINERIES?
Toole A, Lane PH, Arbogast C, Smith WR, Peter R, Locke EG, Beglinger E, Erickson: Charcoal Production, marketing and uses, Forest Product Laboratory.
Madison Wisconsin. US Department of Agriculture, 1961
Brown NC: The Hardwood distillation Industry in New York. The New York State College of Forestry at Syracuse University, 1917.
B.- SLOW PYROLYSIS (350-600 oC)
WOOD DISTILLATION INDUSTRY (FIRST BIO-OIL REFINERY)
BIOMASS
SLOW PYROLYSIS
(CARBONIZATION)
CONDENSER
GASES
CHARCOAL
PYROLYGNEOUS
WATER
SETTLED TAR
(DECANTED OIL)
EVAPORATION
DISTILLATE CONTAINING
ACETIC ACID
MILK OF LIME
NEUTRALIZATION
CRUDE WOOD NAPHTA
RECTIFICATION
DISSOLVED TAR
ACETONE
CALCIUM
ACETATE
CRUDE
WOOD
SPIRIT
WATER
1 Klar
M, Rule A: The technology of Wood Distillation. Chapman & Hall, LTD, 1925
DESTRUCTIVE
DISTILLATION
Acetone: 12-14 %
Methyl alcoho: 50-55 %
Another organics: 5-10 %
Water: 26-28 %
B.- SLOW PYROLYSIS (350-600 oC)
WOOD DISTILLATION INDUSTRIES1
1870-1900 GREAT DEVELOPMENT OF WOOD DISTILLATION INDUSTRY.
15 m3 RETORT
CONDENSER TUBES
CONDENSER
TANK
FURNACE
CONDENSER
PORTABLE RETORT
RETORT
COLLECTING VAT
1 Klar
M, Rule A: The technology of Wood Distillation. Chapman & Hall, LTD, 1925
B.- SLOW PYROLYSIS (350-600 oC)
SWEDISH CARBO-OVEN
(CAPACITY 300-400 m3)
BOSNIAN MEILER OVEN (50 m3)
MODIFIED FORM OF THE
SCHWARTZ KILN
AMERICAN KILN
1 Klar
M, Rule A: The technology of Wood Distillation. Chapman & Hall, LTD, 1925
B.- SLOW PYROLYSIS (350-600 oC)
1870-1900 GREAT DEVELOPMENT OF WOOD DISTILLATION INDUSTRY.
GAS
LIQUID
SEPARATOR
CONDENSER
WATER-TANK
DEVICES FOR SEPARATING
WOOD GAS AND
PYROLYGNEOUS ACID
CONTINUOUS NEUTRALIZATION OF MILK OF LIME
SCRUBBING
THE
NONCONDENSABLE WOOD-GAS
1 Klar
BIO-REFINERIES BASED
ON SLOW PYROLYSIS
M, Rule A: The technology of Wood Distillation. Chapman & Hall, LTD, 1925
B.- SLOW PYROLYSIS (350-600 oC)
1870-1900 GREAT DEVELOPMENT OF WOOD DISTILLATION INDUSTRY.
MULTIPLE
EVAPORATOR
FOR
THE
CONTINUOUS
EVAPORATION OF ACETATE LIQUOR BY EXHAUST STEAM
APPARATUS FOR THE CONTINUOUS DISTILLATION
OF PYROLYGNEOUS ACID
CONTINUOUS DISTILLATION OF
PYROLYGNEOUS ACID
APPARATUS FOR THE MANUFACTURE OF
ACETIC ACID
1 Klar
M, Rule A: The technology of Wood Distillation. Chapman & Hall, LTD, 1925
MECHANICAL DRUM-DRIER FOR THE PRODUCTION OF SOLID
ACETATE OF LIME
B.- SLOW PYROLYSIS (350-600 oC)
Bates J.S. Distillation of hardwood in Canada. Department of the Interior, Canada, 1922.
B.- SLOW PYROLYSIS (350-600 oC)
IN THE LAST 80 YEARS SLOW PYROLYSIS HAS RECEIVED LITTLE ATTENTION. NO
CHARCOAL PRODUCTION TECHNOLOGY ABLE TO COMPLY WITH NORTH AMERICA
ENVIRONMENTAL STANDARDS IS CURRENTLY AVAILABLE .
Brick beehive-large scale conversion low grade wood
Concrete kiln
3.- SLOW PYROLYSIS (350-600 oC)
NEED FOR MORE RESEARCH ON SLOW PYROLYSIS. DEVELOPMENT OF NEW PROTOTYPES
1961
Toole A, Lane PH, Arbogast C, Smith WR, Peter R, Locke EG, Beglinger E, Erickson: Charcoal Production, marketing and uses, Forest Product Laboratory. Madison
Wisconsin. US Department of Agriculture, 1961
3.- SLOW PYROLYSIS
SLOW PYROLYSIS IN DEVELOPING NATIONS
B.- SLOW PYROLYSIS (350-600 oC)
The current trend in charcoal production aims at improving the
environmental performance while maintaining and/or improving
charcoal yield and quality. Steel vessels or retorts are filled with pre-dried
wood and placed in a ceramic brick-lined carbonization furnace heated to
600°C. The tars and gases produced as the wood heats up are led to a
separate high-temperature combustion chamber. The flue gas from this
combustion chamber is used to heat the carbonization furnace, and the
remaining heat from the furnace is used to pre-dry the wood. The very good
heat management of this type of equipment makes it possible to produce
1 kg of charcoal from 3 to 4 kg of wood.
Because of the very high temperature of
the combustion chamber, all particles,
tars and gases are completely
combusted. These equipments have
been certified to meet strict emission
standards
for
combustion
installations. Emissions of tars, carbon
monoxide and nitrogen oxide as well as
smell components are well within the
legal limits.
B.- SLOW PYROLYSIS (350-600 oC)
SLOW PYROLYSIS FOR THE PRODUCTION OF HEAT
SCHEMATIC DIAGRAM SHOWING PROCESSES AND THE FLOW OF MATERIAL IN A CONTINUOUS, AUGER
BASES, SLOW PYROLYZER. BIOCHAR, ELECTRICITY AND HEAT ARE PRIMARY PRODUCTS OF THIS CONCEPT
Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels,
Bioproducts & Biorefining. 2009, 547-561
C.- FAST PYROLYSIS (350 – 600 oC)
1970s- OIL CRISIS (FLUIDIZED BED REACTORS)
1980s- FUNDAMENTALS OF
OF NEW PYROLYSIS REACTORS.
BIOMASS
PYROLYSIS
AND DEVELOPMENT
1980s- PROGRESS IN BIO-OIL CHARACTERIZATION
1990s- SEVERAL FAST PYROLYSIS TECHNOLOGIES REACH COMMERCIAL OR NEAR
COMMERCIAL STATUS
1990s- COMBUSTION OF CRUDE BIO-OILS AT ATMOSPHERIC PRESSURE IN FLAME
TUNNELS AND BOILERS.
1990s- COMBUSTION OF BIO-OILS IN GAS TURBINES AND DIESEL ENGINES AND
UNDERSTANDING BIO-OIL COMBUSTION PHENOMENA
1990s- PROPOSED SPECIFICATIONS FOR FUEL APPLICATIONS
1990s- BIO-OILS UPGRADING: (DEVELOPMENT OF BIO-OILS MICRO-EMULSIONS),
HOT VAPOR FILTRATION, USE OF ADITIVES.
C.- FAST PYROLYSIS (350 – 600 oC)
1990s- BIO-OIL PHYSICO CHEMICAL STRUCTURE
1990s- STUDY OF FUEL PROPERTIES OF BIO-OIL BLENDS
1990s- DEVELOPMENT OF NEW BIO-OIL SEPARATION METHODS
1990s- NEW PRODUCTS FROM CRUDE BIO-OILS (Bio-Lime, Slow Release
Fertilizers, Road de-icers, Wood Preservatives, Glues, Sealing materials, biopitches, Hydrogen, Meat Browning Agents, Hydroxyacetaldehyde, Phenolformaldehyde resins)
2000s- DEVELOPMENT OF NEW BIO-OIL BASED REFINERY CONCEPTS
C.- FAST PYROLYSIS (350 – 600 oC)
FAST PYROLYSIS: IS A HIGH TEMPERATURE PROCESS IN WHICH BIOMASS IS RAPIDLY HEATED
(AROUND 300 oC PER SECOND) IN THE ABSENCE OF OXYGEN. LIQUID PRODUCTION REQUIERES
VERY LOW VAPOR RESIDENCE TIME TO MINIMIZE SECONDARY REACTIONS OF TYPICALLY 1
SECOND (BUT 5 SECONDS ARE ACCEPTABLE). IT INVOLVES RAPID HEATING OF BIOMASS.
GENERALLY FAST PYROLYSIS IS USED TO OBTAIN HIGH-YIELD OF BIO-OIL. RESEARCHER HAS
SHOWN THAT MAXIMUM LIQUID YIELDS ARE OBTAINED WITH HIGH HEATING RATES AT
TEMPERATURES AROUND 500 oC
THE
GROUP
AT
THE
UNIVERSITY OF WATERLOO,
CANADA DEVELOPED THE
FLASH PYROLYSIS PROCESS
WHICH IS BASED ON THE
ADIABATIC FLUIDIZED BED
PYROLYSIS
OF
LIGNOCELLULOSIC MATERIALS.
UNIVERSITY OF WATERLOO PILOT PLANT DIAGRAM
Meier D, Faix O: State of the art of applied fast pyrolysis of lignocellulosic materials- a review. Bioresource Technology 68 (1999) 71-77
C.- FAST PYROLYSIS (350 – 600 oC)
BUBBLING FLUIDIZED BED
DYNAMOTIVE: (http://www.dynamotive.com)
HEAT SUPPLIED EXTERNALLY TO BED
GOOD MASS & HEAT TRANSFER
REQUIRES SMALL BIOMASS
PARTICLES (2-3 mm)
Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading . http://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/RobertBrown&
JenniferHolmgren presentationslides.pdf
C.- FAST PYROLYSIS (350-600 oC)
YIELD OF PRODUCTS
PROCESS
LIQUID
(BIO-OIL)
SOLID
(BIO-CHAR)
FAST PYROLYSIS
60-75 %
(10-25 % WATER)
SLOW
PYROLYSIS
30-45 %
(25-70 % WATER)
20-35 %
GASIFICATION
5-10 %
(5 % WATER)
10 %
12-20 %
GAS
(SYNGAS)
13-20 %
20-35 %
85 %
C.- FAST PYROLYSIS (350 – 600 oC)
EFFECT OF PARTICLE SIZE
Time taken for a particle of a given
size to reach a mean temperature
of half that of the heat transfer
environment
Properties of wood
Particle size and heating rates in wood
C.- FAST PYROLYSIS (350 – 600 oC)
EFFECT OF EXTERNAL HEAT TRANSFER COEFICIENT
Effect of external heat transfer coefficient on the conversion time
C.- FAST PYROLYSIS (350 – 600 oC)
THE EFFECT OF VAPOUR RESIDENCE TIME ON ORGANIC LIQUID YIELD IS RELATIVELY WELL
UNDERSTOOD ALTHOUGH THE INTERACTIONS OF TEMPERATURE AND RESIDENCE TIME IS
LESS UNDERSTOOD.
THE WINDOW FOR FUEL PRODUCTION REQUIERES MORE R & D TO BETTER UNDERSTAND
THE PROCESSES AND MATCH THE PRODUCT QUALITY REQUIREMENT TO PROCESS
PARAMETERS.
THE PRODUCT VAPORS ARE NOT TRUE VAPORS BUT RATHER A MIST OR FUME AND ARE
TYPICALLY PRESENT IN AN INERT GAS AT RELATIVELY LOW CONCENTRATIONS WHICH
INCREASES COOLING AND CONDENSATION PROBLEMS. THIS CONTRIBUTES TO THE
COLLECTION PROBLEMS AS THE AEROSOLS NEED TO BE IMPINGED ONTO SURFACE TO
PERMIT COLLECTION, EVEN AFTER COOLING TO BELLOW THE DREW POINT TEMPERATURE.
ELECTRICTATIC PRECIPITATORS ARE EFFECTIVE BUT CAN CREATE PROBLEMS FROM THE
POLAR NATURE OF THE PRODUCT AND ARCHING OF THE LIQUIDS AND THEY FLOW, CAUSING
ELECTROSTATIC PRECIPITATOR TO SHORT OUT. LARGE SCALE PROCESSING UNITS EMPLOYS
QUENCHING SYSTEMS (SCRUBBERS). CAREFULL DESIGN IS NEEDED TO AVOID BLOCKAGE
FROM DIFFERENTIAL CONDENSATION OF HEAVY ENDS. THE RATE OF COOLING SEEMS TO BE
IMPORTANT. TRANSFER LINES FROM THE REACTOR TO THROUGH THE CYCLONE(S) TO THE
LIQUID COLLECTION SYSTEM SHOULD BE MAINTAINED AT TEMPERATURES OVER 400 oC TO
MINIMIZE LIQUID DEPOSITION.
C.- FAST PYROLYSIS (350 – 600 oC)
HEAT TRANSFER
THERE ARE TWO IMPORTANT REQUIRMENETS FOR HEAT TRANSFER IN A PYROLYSIS REACTOR:
(1) TO THE REACTOR HEAT TRANSFER MEDIUM (SOLID REACTOR WALL IN ABLATIVE
REACTORS, GAS AND SOLID IN FLUID AND TRANSPORT BED REACTORS, AND GAS IN
ENTRAINED FLOW REACTORS.
(2) FROM THE HEAT TRANSFER MEDIUM TO THE PYROLYZING BIOMASS
HEATING THE BIOMASS PARTICLE: GAS SOLID HEAT TRANSFER FROM THE HOT GAS TO THE
PYROLYSING BIOMASS PARTICLE BY PRIMARY CONVECTION, AND SOLID-SOLID HEAT
TRANSFER WITH MOSTLY CONVECTIVE HEAT TRANSFER IN ABLATIVE PYROLYSIS. FLUID BED
PYROLYSIS UTILIZES THE INHERENTLY GOOD SOLIDS MIXING TON TRANSFER APROXIMATELY 90
% OF THE HEAT TO THE BIOMASS BY SOLID-SOLID HEAT TRANSFER WITH A PROBABLE SMALL
CONTRIBUTION FROM GAS SOLID CONVECTION HEAT TRANSFER (UP TO 10 %). SOME
RADIATION EFFECT OCCUR IN ALL REACTORS
SINCE THE THERMAL CONDUCTIVITY OF BIOMASS IS VERY POOR (0.1 W/mK ALONG THE
GRAIN AND ONLY 0.05 W/mK CROSS GRAIN). RELIANCE ON GAS SOLID HEAT TRANSFER
MEANS THAT BIOMASS PARTICLES HAVE TO BE VERY SMALL TO FULFIL THE REQUIREMENTS OF
RAPID HEATING TO ACHIEVE HIGH LIQUID YIELDS. CLAIMED HEATING RATES OF 10,000 oC/s
MAY BE ACHIEVED AT THE THIN REACTION LAYER BUT THE LOW THERMAL CONDUCTIVITY OF
WOOD WILL PREVENT SUCH TEMPERATURE GRADIENTS THROUGHOUT THE WHOLE
PARTICLE. AS PARTICLE SIZE INCREASES, LIQUID YIELDS REDUCE AS SECONDARY REACTIONS
WITHIN THE PARTICLE BECOME INCREASINGLY SIGNIFICANT.
C.- FAST PYROLYSIS (350-600 oC)
PYROLYSIS OILS ARE DARK
BROWN LOW VISCOSITY LIQUIDS
WITH 75-80 mass % OF
ORGANICS ; 15-20 % WATER
Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading . http://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/RobertBrown& JenniferHolmgren
presentationslides.pdf
C.- FAST PYROLYSIS (350 – 600 oC)
ABLATIVE PYROLYSIS: WOOD IS PRESSED AGAINST A
HEATED SURFACE AND RAPIDLY MOVED DURING WHICH
THE WOOD MELTS AT THE HEATED SURFACE AND
LEAVES AN OIL FILM BEHIND WHICH EVAPORATES. THIS
PROCESS USES LARGER PARTICLES OF WOOD AND IS
TYPICALLY LIMITED BY THE RATE OF HEAT SUPPLY TO
THE REACTOR. IT LEADS TO COMPACT AND INTENSIVE
REACTORS THAT DO NOT NEED CARRIER GAS BUT WITH
THE PENALTY OF A SURFACE AREA CONTROLLED SYSTEM
AND MOVING PARTS AT HIGH TEMPERATURE.
FLUID BED AND CIRCULATING FLUID BED PYROLYSIS:
THE HEAT IS TRANSFERRED BY A MIXTURE OF
CONVECTION AND CONDUCTION. THE HEAT TRANSFER
LIMITATION IS WITHIN THE PARTICLE, THUS
REQUIERING VERY SMALL PARTICLES OF TYPICALLY NO
MORE THAN 3 MM TO OBTAIN GOOD YIELDS.
SUBSTANTIAL CARRIER GAS IS NEEDED FOR
FLUIDIZATION OR TRANSPORT.
VACUUM PYROLYSIS: SLOW HEATING RATES BUT THE
VAPOURS ARE REMOVED FROM THE REACTOR IN THE
PRESENCE OF VACUUM
(a) Fluidized bed, (b) circulating bed (c) ablative pyrolysis (d)
rotating cone reactor, (e) vortex reactor (f) vacuum pyrolysis.
Meier D, Faix O: State of the art of applied fast pyrolysis of lignocellulosic materials- a review. Bioresource Technology 68 (1999) 71-77
C.- FAST PYROLYSIS (350 – 600 oC)
CIRCULATING FLUID BED/TRANSPORT REACTOR
ENSYN
(http://www.ensyn.com/index.htm)
HOT SAND CIRCULATED BETWEEN
COMBUSTOR AND PYROLYZER
HEAT SUPPLIED FROM BURNING
CHAR
HIGH THROUGHPUTS BUT MORE
CHAR ATTRITION
Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading . http://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/RobertBrown& JenniferHolmgren
presentationslides.pdf
C.- FAST PYROLYSIS (350 – 600 oC)
ROTATING CONE PYROLYZER
BTG (http://www.btgworld.com/index.php?r=company)
HIGH PRESSURE OF PARTICLE ON HOT REACTOR WALL
ACHIEVED BY CENTRIFUGAL OR MECHANICAL MOTION.
CAN USE LARGE PARTICLES AND DOES NOT REQUIRE
CARRIER GAS
COMPLEX AND DO NOT SCALE WELL
SAND AND BIOMASS BROUGHT INTO CONTACT WITHIN
ROTATING CONE
COMPACT DESIGN AND DOES NOT NEED CARRIER GAS
Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading . http://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/RobertBrown& JenniferHolmgren
presentationslides.pdf
C.- FAST PYROLYSIS (350 – 600 oC)
Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading . http://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/RobertBrown& JenniferHolmgren
presentationslides.pdf
C.- FAST PYROLYSIS (350 – 600 oC)
REACTOR TYPES AND HEAT TRANSFER
REACTOR TYPE
SUGGESTED MODE OF
HEAT TRANSFER
ADVANTAGES/DISADVANTAGES/FEATURES
ABLATIVE
95 % CONDUCTION
4 % CONVECTION
1 % RADIATION
ACCEPT LARGE SIZE FEEDSTOCKS, VERY HIGH
MECHANICAL CHAR ABRASION, COMPACT
DESIGN, HEAT SUPPLY PROBLEMATICAL, HEAT
TRANSFER GAS NOT REQUIRED, PARTICLE
TRANSPORT GAS NOT ALWAYS REQUIERED
CIRCULATING FLUID BED
80 % CONDUCTION
19 % CONVECTION
1 % RADIATION
HIGH HEAT TRANSFER RATES, HIGH CHAR
ABRASION , CHAR/SOLID HEAT CARRIER
SEPARATION REQUIERED, SOLIDS RECYCLE
REQUIRED, INCREASED COMPLEXITY OF THE
SYSTEM, MAXIMUM PARTICLE SIZE UP TO 6 mm,
POSSIBLE LIQUIDS CRACKING BY HOT SOLIDS,
POSSIBLE CATALYTIC ACTIVITY FROM CHAR,
GREATER REACTOR WEAR POSSIBLE
FLUID BED
ENTRAINED FLOW
90 % CONDUCTION
9 % CONVECTION
1 % RADIATION
HIGH HEAT TRANSFER RATES, HEAT SUPPLY TO
FLUIDIZING GASE OR TO BED DIRECTLY, LIMITED
CHAR ABRASION, VERY GOOD SOLID MIXING,
PARTICLE SIZE LIMIT < 2 mm IN SMALLEST
DIMENSION, SIMPLE REACTOR CONFIGURATION
4 % CONDUCTION
95 % CONVECTION
1 % RADIATION
LOW HEAT TRANSFER RATES, PARTICLE SIZE LIMIT
< 2mm, LIMITING GAS/SOLID MIXING
C.- FAST PYROLYSIS (350 – 600 oC)
PLANT ENGINEERS ACCOUNT FOR THE AMOUNT OF ENERGY CONSUMED WITHIN
THE BOUNDARIES OF A PYROLYSIS PLANT. THIS ENERGY IS USUALLY COUNTED
AGAINST THE MAJOR PRODUCT OF THE PLANT, ALTHOUGH IT CAN BE APPRORTIONED
AMONG THE VARIOUS BYPRODUCTS. THE EFFICIENCY OF A MODERN FAST
PYROLYSIS PLANT CONSIDERING THAT THE BIO-OIL IS THE ONLY PRODUCT OF THE
PLANT IS ABOUT 70 %. HOWEVER, IF THE ENERGY CONTENT OF THE CHAR IS
CONSIDERED, THE OVERALL EFFICIENCY IS MORE THAN 90 %.
SCALABILITY
PYROLYZERS RANGE IN SIZE FROM LABORATORY DEVICES THAT PROCESS AS LITTLE
AS A FEW MILLIGRAMS OF MATERIALS PER TEST TO INDUSTRIAL EQUIPMENT
PROCESSING MANY TONS PER HOUR. THE LARGEST FACILITY IN NORTH AMERICA ARE
CAPABLE OF PROCESSING 250 AND 200 DRY TONS OF BIOMASS PER DAY. PYROLYSIS
CAN BE SCALED FROM SMALL TO LARGE TO OPTIMIZE THE BALANCE BETWEEN
ECONOMIES OF SCALE ASSOCIATED WITH PROCESSING BIOMASS AT A LARGE
CENTRALIZED FACILITY AND REDUCED BIOMASS TRANSPORTATION, STORAGE AND
HANDLING COST THAT ACCRRUE FROM PROCESSING BIOMASS THROUGH A
DISTRIBUTED NETWORK OF SMALL FACILITIES LOCATED CLOSE TO BIOMASS
RESOURCE.
Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels,
Bioproducts & Biorefining. 2009, 547-561
C.- FAST PYROLYSIS (350 – 600 oC)
Biomass
Biomass
PRETREATMENT
Biomass
PRETREATMENT
PYROLYSIS
CHARCOAL
Biomass
BIO-OIL
PYROLYSIS
CHARCOAL
BIO-OIL
PYROLYSIS
CHARCOAL
PRETREATMENT
BIO-REFINERY
BIO-OIL
PYROLYSIS
PRETREATMENT
CHARCOAL
Main Products for
Large Markets (Green
Gasoline, Green
Diesel, Ethanol)
High Value Products
(Chemicals, Polymers)
THE MAIN GOAL OF A BIO-REFINERY IS TO PRODUCE HIGH-VALUE LOW VOLUME (HVLV) AND
LOW VALUE HIGH-VOLUME (LVHV) PRODUCTS USING A SERIES OF UNIT OPERATIONS
- Pelaez-Samaniego MR, Garcia-Perez M, Cortez LB, Rosillo-Calle F, Mesa J: Improvements of Brazilian Carbonization Industry as Part of the
Creation of a Global Biomass Economy. Accepted in: Renew. Sust. Energ. Rev., 2008, v. 12, n 4, p. 1063-1086
- Badger PC, Fransham P: Use of Mobile Fast Pyrolysis Plants to densify Biomass and Reduce Biomass Handling Costs - A Preliminary
Assessment, Biomass and Bioenergy 30, 2006, 321–325
C.- FAST PYROLYSIS (350 – 600 oC)
MULTI-FEEDSTOCK PRODUCTION OF BIO-CHAR AND MULTIAPPLICATION USE.
BIOCHAR CAN RESULT IN A NET REMOVAL OF
CARBON FROM THE ATMOSPHERE AND AT THE
SAME TIME ENHANCE SOIL PRODUCTIVITY
Sohi S, Lopez-Capen E, Krull E, Bol R: Biochar climate change and soil: A review to guide future research, CSIRO, 2008.
C.- FAST PYROLYSIS (350 – 600 oC)
INDUSTRIAL UNITS (200-2,000 t/day)
Ensyn
BTG
Dynamotive
MOBILE UNITS (50-200 t/day)
(ABRI)
C.- FAST PYROLYSIS (350 – 600 oC)
BIO-OIL REFINERIES (HYDROTREATMENT CONCEPT)
THE USE OF BIOMASS RESOURCES TO PRODUCE INFRASTRUCTURE COMPATIBLE FUEL IS
APPEALING. HYDROCARBON FUELS CAN BE USED WITHOUT SIGNIFICANT CHANGES TO
CURRENT FUEL DISTRIBUTION INFRASTRUCTURE.
Jones SB, Holladay JE, Valkenburg C, Stevens DJ, Walton C, Kinchin C, Elliott DC, Czernik S: Production of Gasoline and Diesel from Biomass via
Fast Pyrolysis, Hydrotreating and Hydrocracking: A Design Case. US Department of Energy, February 2009, PNNL-18284 Rev. 1. DE-AC0576RL01830
C.- FAST PYROLYSIS (350 – 600 oC)
FAST PYROLYSIS OIL UPGRADING
UNTREATED BIO-OIL IS A DARK BROWN, FREE-FLOWING LIQUID WITH ABOUT 20 % WATER. BIO-OIL
CAN BE STABILIZED AND CONVERTED TO A CONVENTIONAL HYDROCARBON FUEL BY REMOVING THE
OXYGEN THROUGH HYDROTREATING. HYDROTREATING TO REMOVE NITROGEN AND SULFUR FROM
HYDROCARBONS IS A COMMON AND WELL ESTABLISHED REFINERY PROCESS. OXYGEN REMOVAL ON
THE SCALE NEEDED TO UPGRADE PYROLYSIS OILS IS RELATIVELY NEW AND IN THERESEARCH STAGES.
THE UPGRADING STEP INCLUDES CONTACTING THE BIO-OIL WITH HYDROGEN UNDER PRESSURE AND
AT MODERATE TEMPERATURE (< 400 oC) OVER FIXED BED REACTORS. SINGLE STAGE HYDROTREATING
HAS PROVED TO BE DIFFICULT, PRODUCING A HEAVY, TAR LIKE PRODUCT. DUAL STAGE PROCESSING,
WHERE MILD HYDROTREATING IS FOLLOWED BY MORE SEVERE HYDROTEATING HAS PROVED TO BE
TECHNICALLY VIABLE. OVERALL THE PYROLYSIS OIL IS ALMOST COMPLETELY DEOXYGENATED BY A
COMBINATION OF HYDRODEOXYGENATION AND DECARBOXYLATION:
LESS THAN 2 % OXYGEN REMAINS IN THE TREATED STABLE OIL. WATER AND OFF-GAS ARE PRODUCED
AS BYPRODUCTS. THE WATER PHASE CONTAINS SOME DISSOLVED ORGANICS, WHILE THE OFF GAS
CONTAINS LIGHT HYDROCARBONS. ONCE STABILIZED THE OIL CAN BE FURTHER REFINED INTO
CONVENTIONAL FUELS.
Jones SB, Holladay JE, Valkenburg C, Stevens DJ, Walton C, Kinchin C, Elliott DC, Czernik S: Production of Gasoline and Diesel from Biomass via
Fast Pyrolysis, Hydrotreating and Hydrocracking: A Design Case. US Department of Energy, February 2009, PNNL-18284 Rev. 1. DE-AC0576RL01830
C.- FAST PYROLYSIS (350 – 600 oC)
FLOW DIAGRAM FOR PYROLYSIS OIL STABILIZATION (BIO-OIL REFINERIES)
HYDROGEN
PYROLYSIS OIL
Cost of production: 1.74 $/gal
gasoline/diesel
FUEL GAS TO
REFORMER
2000 T/DAY OF HYBRID POPLAR UNIT TO PRODUCE 76 MILLION
GALLONS/YEAR OF GASOLINE AND DIESEL (115 gal/t)
UP-GRADED
BIO-OIL TO
DEBUTANIZER
WASTE WATER
Jones SB, Holladay JE, Valkenburg C, Stevens DJ, Walton C, Kinchin C, Elliott DC, Czernik S: Production of Gasoline and Diesel from Biomass via
Fast Pyrolysis, Hydrotreating and Hydrocracking: A Design Case. US Department of Energy, February 2009, PNNL-18284 Rev. 1. DE-AC0576RL01830
D.- CONCLUSIONS
PYROLYSIS IS THE ONLY TECHNOLOGY
AVAILABLE TO PRODUCE CHARCOAL. MOST OF
CURRENT RESEARCH AND DEVELOPMENT IN
PYROLYSIS AIMS AT PRODUCING HIGH YIELDS
OF A BIO-OIL THAT WILL BE FURTHER REFINED
TO PRODUCE TRANSPORTATION FUELS. YIELDS
AS HIGH AS 28 % OF GREEN GASOLINE AND
GREEN DIESEL FROM LIGNOCELLULOSIC
MATERIALS HAVE BEEN REPORTED. THERE IS
AN INCREASING INTEREST TO PRODUCE BIOCHAR FOR CARBON SEQUESTRATION.