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Techno-economic (TEA) and Life Cycle Analysis (LCA) of the Pyrolysis-Bioenergy-Biochar
Pathway to Carbon-Negative Energy
Wenqin Li, Qi Dang, Mark Mba Wright,
Robert C. Brown, David Laird
November 1, 2016
Background - GHG emissions
2[1] https://www.epa.gov/climate-indicators/climate-change-
indicators-us-greenhouse-gas-emissions
In 2014: 6870
MM MT CO2e
26% of Total
GHG emissions
31% of Total
GHG emissions
U.S. Greenhouse Gas Emissions by Economic Sector1, 1990-2014
Pyrolysis-Bioenergy-Biochar
platform
3
Cellulosic biomass
“Carbon Negative
Energy”
[2] Laird et al., 2011. www.swcs.org/roadmap
Objectives
4
• Process Modeling
– Evaluate feedstock properties’ impacts on product yields
• Techno-economic Analysis (TEA)
– Evaluate feedstock properties’ impacts on economics
• Life Cycle Analysis (LCA)
– Evaluate feedstock properties’ impacts on environments
Fast pyrolysis to biofuel & biochar
pathway
5
H2 Reformer
Chopper
Cyclones
Fluidizing
Gas
Pyrolysis
Heat
Air
SF1
Condenser
SF3
Condenser
SF4
ESP
SF5
Condenser
SF2
ESP
H2O H2O
Reduction
ReactorReaction
Reactor
Pyrolysis
Reactors
Separator
Recycle
Steam
Off Gas
DryerGrinder
NCG
(From SF5 Condenser)
Compressor CompressorPSA
H2
Stable
Oil
Valve
Ash
H2O
H2O
Distillation
Tower
SF1 SF2 SF3 SF4
Char
Hydrocracker
Biomass
Moisture
Off Gas
Off Gas
Gasoline
Diesel
Natural
Gas H2O
SF5
Non-
Condensable
Gas (NCG)
Pyrolysis
Vapor
H2
Bottom
Heavy
Oil
Top
Light
Oil
Steam
Generator
Natural Gas
Regression Model
6
wt. % Sweetgum Beech Bark Acacia Acacia Bark Corn Stover Red Oak Switchgrass Sourwood Yellow Poplar Red Maple BeechLoblolly Pine
Carbon 46.4 44.5 48.4 49.9 43.2 49.6 46.6 46.9 47.1 47.4 48.2 48.4
Ash 0.8 7.4 0.6 3.3 8.1 0.4 1.4 0.5 0.6 0.3 0.5 0.6
Oxygen 47.7 42.9 45.9 40.7 41.4 43.9 46.6 47.5 47.2 47.2 45.8 46.3
Water 10.5 26.4 12.9 19.0 23.8 19.8 13.8 8.2 10.1 9.0 10.2 14.0
Organics 55.1 29.2 43.9 33.8 27.7 43.4 51.4 58.0 52.3 53.5 54.0 50.7
Char 9.0 24.6 10.7 21.7 21.7 13.5 9.5 6.3 7.4 7.0 10.6 10.0
NCG 25.4 19.8 32.5 25.5 26.9 23.3 25.3 27.5 30.2 30.5 25.2 25.3
𝑂𝑟𝑔𝑎𝑛𝑖𝑐𝑠 = −13.13 + 69.09 × (𝑂/𝐶) − 4.67 × 𝐴𝑠ℎChar = 58.16 − 51.52 × (𝑂/𝐶) + 2.78 × Ash𝑁𝐶𝐺 = 20.34 + 6.48 × (𝑂/𝐶) − 0.07 × 𝐴𝑠ℎ𝑊𝑎𝑡𝑒𝑟 = 46.78 − 36.84 × (𝑂/𝐶) + 2.24 × 𝐴𝑠ℎ
[3] From North Carolina State University by Carlos E. Aizpurua, Hoyong Kim.Drs. Stephen S. Kelley, Hasan Jameel, and Sunkyu Park)
Note: C: carbon content in feedstock; O: oxygen content in feedstock; Ash: ash content in feedstock.
Experimental Data3 (Ultimate analysis on a dry basis)
Experimental vs. prediction data
7𝑬𝒓𝒓𝒐𝒓 = |𝑷𝒓𝒆𝒅𝒊𝒄𝒕𝒊𝒐𝒏 − 𝑬𝒙𝒑𝒆𝒓𝒊𝒎𝒆𝒏𝒕𝒂𝒍
𝑷𝒓𝒆𝒅𝒊𝒄𝒕𝒊𝒐𝒏| < 𝟏𝟎%
Feedstock data analysis
8
Ultimate analysis of five types of biomass 4
[4]Ultimate analysis of different feedstockcomes from ECN Phyllis 2. https://www.ecn.nl/phyllis2/
Char yield vs. O/C of biomass
9
Fuel yield vs. O/C of biomass
10
Char yield vs. O/C of biomass
(ash level)
11
Fuel yield vs. O/C of biomass
(ash level)
12
Char yield vs. ash content of biomass
13
Fuel yield vs. ash content of biomass
14
Economic assumptions
15
− Assume feedstock costs are the same;
− Assume capital costs are the same.
Feedstock Mass Flow Rate 2000 MT/day
Feedstock Cost 83 $/MT
Biochar selling price 20 $/MT
Natural gas 260 $/MT
Internal rate of return 10%
Plant life 30 year
Capital cost distribution
16
Operating cost distribution
17
An
nu
al O
pe
rati
ng
Co
st (
$/g
al)
Average Operating Cost: $3.07-3.76/gal
MFSP vs. O/C and ash of biomass
18
Life cycle analysis-System boundary
19
Functional unit: 1 MJ Fuel produced
Feedstock production emission data
source
20
Feedstock type Representative Resources
Wood Forest Residue GREET
Straw Corn Stover GREET
Grass Switchgrass SimaPro 7.3
Organic Residue Bagasse(from Sweet Sorghum) SimaPro 7.3
Husk Palm Kernel SimaPro 7.3
GHG emissions vs. O/C of biomass
21
GHG emissions vs. ash of biomass
22
GHG emission distribution
23
Tota
l GH
G E
mis
sio
ns
(g C
O2e
/MJ
Fue
l)
Petroleum Gasoline GHG Emissions: 93g CO2e/MJ Fuel
Net GHG Emission Reduction: 50%-69%
RFS GHG Emission Reduction for advanced fuels: 50%
Conclusions
24
• O/C and ash content of biomass have significant impacts on the
product yields:
– Higher O/C has the potential to increase the biofuel yield, and
decrease biochar yield;
– Higher ash content has the potential to decrease the biofuel yield,
and increase biochar yield.
– Lower O/C ratio is attributed to higher lignin content which tends
to decrease fuel yield for a variety of feedstock
• O/C and ash content of biomass also have significant impacts on
MFSP and GHG emissions:
– Higher O/C has the potential to decrease MFSP and GHG
emissions;
– Higher ash content has the potential to increase MFSP and GHG
emissions.
Future Work
25
Techno-economic (TEA) and life cycle analysis (LCA) of
Pyrolysis-Bioenergy-Biochar platform including regional
factors. Three regions will be considered:
– Upper Mississippi River Basin;
– California;
– U.S. Southeast.
Acknowledgement
26
• Stanford University Global
Climate and Energy Program
(GCEP)
• GCEP Group in Iowa State
University
• Dr. Wright, Dr. Brown and Dr.
Laird
• Students and staff from BEI
Thank you!
Supplementary Slides
GHG emissions vs. fuel yield
GHG emissions vs. fuel yield
30
Background - GHG emissionsM
FSP
($
/gal
)
Fuel Output (MM gallon/year)