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DEVELOPING AN INTEGRATED AGRO-INDUSTRIAL MODEL FOR THE SUSTAINABLE PRODUCTION AND CONVERSION OF BIOMASS INTO BIOFUELS AND
Energy Use of Biomass: a Challenge for Machinery Manufacturers
CONVERSION OF BIOMASS INTO BIOFUELS AND ADDED VALUE PRODUCTS
Paulo Seleghim Jr.University of São Paulo – Brazil
Energy use by Energy use by humankind
target
Energy use by humankind
Energy and quality of lifesaturation
0,900
1,000
IDHIslândia
Noruega
EUA
Canadá
China
HDI
China, IndiaIndonesia, Brazil
41 % increase in world energy consumption
0,300
0,400
0,500
0,600
0,700
0,800
0,900
0 2000 4000 6000 8000 10000 12000
kgoe/capita/year
Moçambique
Brasil
Emirados Árabes
India
2.5 kW 5.0 kW 7.5 kW 10.0 kW 12.5 kW power/capta/year
Bioenergies will play an important role in an important role in meeting these expectations !
But how renewable energies will displace energies will displace
fossil energies ?
Modern bioenergies Modern bioenergies constitute a disruptive
technology…
energy balance
ecological footprint
etc.
1G bioethanol
2G bioethanol
Fuel for Otto cycle engines
Disruptive and incremental evolution of technology
performance
time
time
energy security
cost competitiveness
impact on food prices
worldwide
applicability
etc.
gasoline
we are here
CO2
sequestration technologiesrobustness
Fuel for Otto Cycle engines
2nd generation ethanol: promising energy vector
• Produced from ligno-cellulosic fibers
• Abundant feedstock (crops or wastes)
• Can coexist without impacting on food prices• Can coexist without impacting on food prices
Strategic importance for Brazil – Sugarcane
• Oversupply of electricity from biomass residues in SP
• Need for automotive fuel (↑↑↑↑)
• Sugarcane sector already mature
non-arable 492,6 Mhaarable 354,8 Mha
pasture 172.3 Mhaavailable 105.8 Mha
Environmental planning
Agricultural and livestock land occupation
pasture 172.3 Mhaavailable 105.8 Mhacultivated 76.7 Mha
soya 26.6 Mhacorn 14.0 Mhaorange 0.9 Mhasugar cane 7.8 Mha
• Cultivated area: 7.8 Mha (0.9 % territory)
• Industrial processing units: 432 plants nationwide
• Sugarcane production: 562 million tons / year
Sugarcane sector in Brazil
Characteristic numbers
• Sugarcane production: 562 million tons / year
• Sugar production: 31.2 Mt/year
• Ethanol production: 27 Mm3/year
• Energy matrix share: 16.4% (hydroelectricity = 13%)
• Electricity generation: 2.1 GW
• Electricity potential: 7 GW (Itaipu = 14 GW)
Sugarcane sector in Brazil
Typical sugarcane industrial processing plant
“An AIBPM is a set of mathematical equations An AIBPM is a set of mathematical equations An AIBPM is a set of mathematical equations An AIBPM is a set of mathematical equations
enforcing mass, energy, exergy and monetary enforcing mass, energy, exergy and monetary enforcing mass, energy, exergy and monetary enforcing mass, energy, exergy and monetary enforcing mass, energy, exergy and monetary enforcing mass, energy, exergy and monetary enforcing mass, energy, exergy and monetary enforcing mass, energy, exergy and monetary
balances governing the overall process of biomass balances governing the overall process of biomass balances governing the overall process of biomass balances governing the overall process of biomass
production and transformation into added value production and transformation into added value production and transformation into added value production and transformation into added value
products.products.products.products.”
Sugarcane sector in Brazil
Typical sugarcane industrial processing plant
20 – 40 kha
sunlight water CO2
sugar
CO2
2 t/h
Processing
500 t/hsugar(65 t/h)
ethanol(42 m3/h)
electricity(50 MW)
solids
1-10 t/h
vinasse
500 m3/h
500 t/h
feedstok
nutrients
1000 t/h sugar cane diffuser
Agriculture / Industry equilibrium
Turnover + Efficiency ~ area ~ r2
Plantation area →→→→ Industrial equip. ↑↑↑↑Economies of scaleFeedstock usageTherm. efficiencies
Typical sugarcane mill
Turnover + Efficiency ~ area ~ r2
Plantation area →→→→ Field operations ↓↓↓↓
Field ops. costs ~ area ×××× distance ~ r3
Soil manipulationCrop HarvestingTransportation
$
f.o. cost ~ r3
turnover ~r2
viability limit
Agriculture / Industry equilibrium
Typical sugarcane mill
0
5
10
15
20
25
30
0 10 20 30 40 50 60 70 80 90 100 110 120
frequency (%)
area (kha)
plantation external limit (r)
state of São Paulo
Evolution of the current sugarcane agro-industrial model
Evolving towards a full scale biorefinery
• Biomass depolymerization
� Low vol. / high value chemical products
� High vol. / low value liquid transportation fuels� High vol. / low value liquid transportation fuels
Enhancing sustainability
• Energy balance (currently ~9:1)
• Water balance (currently negative)
• Soil nutrients recycling (currently uneconomical)
An integrated agro-industrial model for the sustainable model for the sustainable
production and conversion of biomass into biofuels and added value products
water
molasses
mechanicalprocessing
juiceextraction
cookingcrystallization
sugar
boiler andturbines
electricity0-50MW
straw
juice
bagasse
130 t/h
sugarsugar
ligninbagassepre-treatment
cellulose
sugar cane500 tc/h
CO2
2 t/h
vinasse
500 m3/h
molasses
juicefermentation
sugarcentrifugation
winedistillation
ethanol0-43 m3/h
sugar0-65 t/h
photo-bioreactor
extractionseparation
conversiontransest.
biodiesel /chemicals
broth
glycerin
nutrientsnutrients
waterwater
sugarsugarcellulose
hydrolization
ethanol0-82 m3/h
These propositions are not viable in current not viable in current technology status
2nd generation ethanol from sugarcane bagasse: A two stages process
• Rupture of macro structures (Pre-treatment)
� Cellulose and hemicellulose fermentable
� Lignin biochemicals or energy
• Depolymerization of fermentable sugars• Depolymerization of fermentable sugars
� Hydrolysis
hemicellulose
cellulose
lignin
• Pre-treatment
� Ammonia or CO2 explosion
� Steam explosion or hydrothermal
� Supercritical fluids, microwave and ozone
scale ?
2nd generation ethanol from sugarcane bagasse: Technological alternatives
� Supercritical fluids, microwave and ozone
� PHWS followed by explosive depressurization
• Cellulose and hemicellulose hydrolysis
� Acid or alkaline
� Enzymatic
efficiency ?
Pre-TreatmentPre-Treatment
2nd generation ethanol from sugarcane bagasse: Pre-Treatment
PHWS followed by explosive depressurization
1. Absorption of liquid water within the macroscopic structures of ligno-cellulose material
2. Solubilisation of lignin2. Solubilisation of lignin
3. Explosive expansion inducing in loco vaporization to foam theligno-cellulosic material
pre-soaking bin
pressure vessel
PHWS followed by explosive depressurization
A continuous pre-treatment system for 150 tsc/h
feeding system
cyclone separator
expansion device
PHWS followed by explosive depressurization
Bentch top batch reactor for operating parameter optimization studies
pressure (bar)
20 bar210 oC
enthalpy (kJ/kg)1 bar100 oC
⊗⊗⊗⊗
⊗⊗⊗⊗
1 bar25 oC
⊗⊗⊗⊗
time
temperature
210 oC
100 oC
metastablestates
metastability →→→→ even more rapid expansion
HydrolysisHydrolysis
Development of a high productivity bioreactor for enzyme production
2nd generation ethanol from sugarcane bagasse: Enzymatic hydrolysis
1. Dispersion of residence times / flow management
2. Cell death / shear stress management2. Cell death / shear stress management
3. Temperature homogeneity / heat management
4. Solids deposition / stagnation zones
5. Etc…
conflicting objectives…
multiobjective optimization…
Design strategy
2nd generation ethanol from sugarcane bagasse: Enzymatic hydrolysis
geometryparameters
X
X1
X2
X1
X
meshgenerator
CFDsolver
optimizationparameters
optimizationmethod
parametercorrections
X2X3
X4
X3X4
shear
stress
disp.
res. time
Pareto frontier
SustainabilitySustainability
Nutrients recycling: The problem
20 – 40 kha
sunlight water CO2
sugar
CO2
2 t/h
Processing
500 t/h
Typical sugarcane industrial processing plant
sugar(65 t/h)
ethanol(42 m3/h)
electricity(50 MW)
solids
1-10 t/h
vinasse
500 m3/h
500 t/h
feedstok
nutrients
975 kg/h of NPK1 ton NPK / 499 ton water
Nutrients recycling: The problem
molasses molassemolasses and sc juice sc juice
Chemical composition of vinasse
Nutrients recycling: The problem
Nutrients recycling: The problem
Problems related to vinasse application
1. Highly uneconomical operation
2. Can strongly impact soil, groundwater, or nearby watercourses or lakeswatercourses or lakes
3. It is necessary to correct vinasse acidity
4. Biodigest organic matter to reduce impacts on soil microorganisms
5. Modify soil mechanical properties, particularly permeability, favoring soil compaction.
Cultivation of microalgae from CO2 and vinasse
Nutrients recycling: The solution (?)
juice
43
ethanol
Prospective configuration:
• Chlorella vulgaris (high photo-
synthetic efficiency ~ 8%)
• Open raceway pond (cheap and
simple operation)
Preliminary design parameters (C.vulgaris):
Nutrients recycling: The solution (?)
Oh-Hama, T.; Miyachi, S. In Microalgal Biotechnology;
Borowitzka, M. A.; Borowitzka, L. J., Eds.; Cambridge
University Press: Cambridge, 1988.
vinasse500 m3/h
N @140 kg/h P @ 43.7 kg/h K @ 609.9 kg/h
÷ 46.0x10-3 kg N/kg µA ÷ 9.9x10-3 kg P/kg µA ÷8.2 x10-3 kg K/kg µA
3043 kg µµµµA/h 4414 kg µµµµA/h 74378 kg µµµµA/h
~300 ha ~400 ha ~7400 ha
÷ 24.75x10-3 kg µA/m2/24h ÷ 24.75x10-3 kg µA/m2/24h ÷ 24.75x10-3 kg µA/m2/24h
Not cost effectivein general
• Prohibitive earthmoving costs• Critical contamination control• Critical temperature control• Etc.
Obtain at least a ten-fold increase in algal productivity (kg/m2/day)
Nutrients recycling: The solution !
Factors afecting algal production
� Inadequate irradiance levels and cycles� Inadequate irradiance levels and cycles
� Deficient photossynthetic O2 removal
� Depletion of CO2
� Bad temperature control
� Contamination
All these factors are interdependent and must be optimized simultaneously !
The coupled The coupled Bio-Photo-Fluidynamic
problem
Cell photosynthesis rate x irradiance
Bio / photo / Fluidynamic coupled problem
µ = Growth rate (g/s)
I = Irradiance (W/m2)
K = Species constants2
21
max
IKIK
I
++
µ=µ
Photoinhibition
Activation
21
max
Kk21+
µ
21 K/k
Light attenuation in function of phase fractions
γ = attenuation coefficient (m-1)
I = Irradiance (W/m2
x = distance from light source (m)
dxIdI ⋅⋅γ−=
Bio / photo / Fluidynamic coupled problem
x0 eI)x(I γ−=
Constant γ in single phase flow
Variable γ in three phase flow
)x(K)()x(K)(x0
pwwwpwbwwwbwww eeeI)x(Iγ−γ−γ−γ−γ− ⋅⋅=
Light attenuation in function of phase fractions
αww = water phase fraction
αbw = CO2 void fraction
αpw = microalgae phase fraction
1pwbwww =α+α+α
Bio / photo / Fluidynamic coupled problem
pwpwbwbwwwpwbweq )1( γα+γα+γα−α−=γ
Equivalent attenuation model
γγγγww = attenuation of water
γγγγbw = attenuation of CO2 (bubbly flow)
γγγγpw = attenuation of microalgae (turbidity)
∫α=x
0
w][w][ dx)x(KKpw(x) = CO2 cumulative void fraction
Kbw(x) = microalgae cumulative phase fraction
Example: phase fractions distributions known a priori
Light attenuation in function of phase fractions
Bio / photo / Fluidynamic coupled problem
Example: phase fractions distributions known a priori
0x
x1
0
bw0,bwbw e
x
x)x(
−α∆+α=α
0x
x1
0
pw0,pwpw e
x
x)x(
−α∆+α=α
normalized values
I(x)
Resulting productivity distribution
0.150.137
normalized values
221
max
)x(IK)x(IK
)x(I)x(
++
µ=µ
Bio / photo / Fluidynamic coupled problem
0 0.2 0.4 0.6 0.8 10
0.05
0.1
0
µ x( )
10 x
excessive
illumination
adequate
illumination
insufficient
illumination
Illumination/darkness cycles
I
excessive
illumination
adequate
illumination
insufficient
illuminationRecirculation caused
by CO2 injectionlight source
Bio / photo / Fluidynamic coupled problem
x
Irradiance in
function of the
distance from
light source
Impact of field related technologies
turnover ~r2
Typical sugarcane mill
$f.o. cost ~ r3
r
productivity, mechanizationharvesting, logisticssoil preparation, fertilizers, irrigation
increasedturnover
increasedplantation area
$
Impact of industrial processing technologies
increased
turnover ~r2
f.o. cost ~ r3
Typical sugarcane mill
new conversion routes, enhanced thermodynamic
efficiencies, feedstock usage,
r
increasedturnover
efficiencies, feedstock usage, economies of scale,
biochemical conversion
increasedplantation area
Energy use by humankind
Power to sustain our life processes
2500 cal/day
120 W
90 W
2000 W
Power to support our lifestyle
90 W
500 EJ/year
2300 W
7 billion people
industry + agriculture (28% = )
transportation sector (27% ↑↑↑↑ )
services + residences (36% ↓↓↓↓ )
Energy use by humankind
With 120W we survive,With 120W we survive,
but we live with 2300W
Disruptive and incremental evolution of technology
performanceDisruptive technologystorage capacity
dimensions
freq. band
etc.
Digital storage media
time
time
robustness New technology is subjected to experimentation,
refinement, and increasingly realistic testing
Evolutive optimization
durability
cost
interchangeability
etc.
