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)