voc emissions from biofuel crops - agro division and air quality... · voc emissions from biofuel...

VOC Emissions from Biofuel Crops

Martin Graus NOAA Chemical Sciences Division

CIRES, University of Colorado, Boulder, Colorado

Introduction Plant cuvette laboratory Leaf cuvette field Flux experiment corn field

Photo: diffusibility.com Photo: scienceprogress.org

Co-Workers: Carsten Warneke (PI) NOAA CSD; CIRES University of Colorado, Boulder Allyson Eller EBIO & CIRES University of Colorado, Boulder Ray Fall BioChem & CIRES University of Colorado, Boulder Joost de Gouw NOAA CSD; CIRES University of Colorado, Boulder Bin Yuan College of Environ Sci and Eng, Peking University Yaling Qian Colorado State University, Fort Collins Philip Westra Colorado State University, Fort Collins


VOC Emissions from Biofuel Crops

1.! What are the dominant VOCs from biofuel crops:

2.! What are the likely oxidation products

3.! What is the total aerosol and ozone forming potential

4.! What biofuel plant species and/or cultivars have the lowest VOC/SVOC

emissions

Phase 1: laboratory and greenhouse measurements

Phase 2: small scale leaf cuvette study in the field

Phase 3: flux measurements in the field: larger scale

Focus on the air quality impacts of the large scale growth of biofuel crops


Volatile organic compounds (VOCs) are precursors for ozone and aerosols

corn, poplars, switchgrass, and miscanthus

!! Corn is the dominant biofuel crop in the US.

!! In 2010 35.7 million ha corn were planted in the US. (size of Germany; in 2011 over 37 million ha ! Japan)

!! In 2010 12.4 billion gal fuel EtOH were produced in the US. (compare 137.9 billion gal total gasoline supplied in the US)

!! At typical yields of 2.60 gal/bu this requires 38% of the total US corn production in 2010.


Motivation: Corn & Switchgrass

1)! USDA NASS report on Acreage (June 30, 2011) 2)! DOE EIA Monthly Energy Review January 2011

!! Very few peer-reviewed corn VOC emission studies published.

!! Emission inventories (including corn) tend to focus on isoprene, terpenes and ‘other VOCs’.

!! Discrepancies in corn emission rates (Lamb et al., 1987, Winer et al., 1989, Lamb et al., 1993, Das et al., 2003)

!! Previously there were no data on VOC emissions from switchgrass.


Photo: diffusibility.com


Photo: scienceprogress.org

Energy Independence and Security Act (2007) requires

!! increase of biofuels added to gasoline form 4.7 billion gal in 2007 to 36 billion gal in 2022

!! 21 billion gal must be produced from non-starch feedstock in 2022.


!! Cellulosic biofuel production is more energy efficient than ethanol production from corn (Hammerschlag, 2006).

!! Switchgrass is a promising feedstock candidate for cellulosic ethanol (Schmer et al. 2008).


Plant cuvette: •! All Teflon •! Large flow of clean air •! Lights automated •! CO2 controlled Species measured: •! switchgrass •! miscanthus •! bamboo •! Corn •! Poplar (future) Instruments: •! PTR-MS for VOCs •! GC-PTR-MS •! GC-MS •! LiCor for CO2

Phase 1: Plant Cuvette Studies


Switchgrass results published by Eller et al, Atmos. Environ. (2011) Miscanthus and bamboo results: Crespo et al, in preparation

Switchgrass Blackwell undisturbed: •! Small daytime emissions of

methanol, acetaldehyde and acetone

•! Very small isoprene and monoterpene emissions

•! Almost no emissions of wound compounds

Plant Cuvette studies of Undisturbed Switchgrass


0.20

0.15

0.10

0.05

0.00

1.251.100.95

0.010

0.008

0.006

0.004

0.002

VO

C e

mis

sio

n r

ate

nm

ol m

-2 s

-1

mass 69 Isoprene

mass 137 Sum of monoterpenes

1:00 AM 9:00 AM 5:00 PM 1:00 AM 9:00 AM 5:00 PM 1:00 AM

0.04

0.03

0.02

0.01

0.00

mass 81 + mass 99 hexenal wound compound

mass 83 + mass 101 hexenol wound compound

mass 143 wound compound

mass 33 Methanol

mass 45 Acetaldehyde

mass 59 Acetone

(+Propanol)

Switchgrass Alamo cutting/harvest and drying: •! Large emissions after cutting of

wound compounds •! Continued emissions during

drying •! Strong decrease of emissions

after one day of drying

Plant Cuvette studies of Switchgrass Harvesting


0.5

0.4

0.3

0.2

0.1

0.0

0.03

0.02

0.01

0.00

VO

C e

mis

sio

n r

ate

nm

ol m

-2 s

-1

mass 69 Isoprene

mass 137 Sum of Monoterpenes

biomass cut

1:00 AM 9:00 AM 5:00 PM 1:00 AM 9:00 AM 5:00 PM 1:00 AM 9:00 AM

0.15

0.10

0.05

0.00

mass 81 + mass 99 hexenal wound compound

mass 83 + mass 101 hexenol wound compound

mass 143 wound compound

biomass cut

biomass cut mass 33 Methanol

mass 45 Acetaldehyde

mass 59 Acetone (+ Propanol)

Growing and harvesting: yield of 12,000 kg ha-1 yr-1 12-hour day April-November growing season •! 3 kg C ha-1 methanol •! 1 kg C ha-1 acetaldehyde •! 1 kg C ha-1 acetone •! 0.5 kg C ha-1 isoprene + 1-penten-3-ol •! 0.9 kg C ha-1 monoterpenes •! 0.1 kg C ha-1 hexenol •! 0.2 kg C ha-1 hexenal

Switchgrass VOC emission estimates from Plant Cuvette studies


Switchgrass VOC emission estimates from Plant Cuvette studies


"! Switchgrass emissions small compared to other potential biofuel crops

•! Comparison with literature data

•! Large variations in emission ratios

•! Corn is weak MT emitter and does not emit isoprene; ‘other VOCs’

may have some significance (Lamb et al., 1993)

Eller et al 2011

Phase 2: Leaf Cuvette studies of Switchgrass and Corn


Leaf cuvette: •! LiCor6400 coupled to

PTR-MS for VOCs

Instruments: •! PTR-MS for VOCs •! LiCor for CO2

a), H2Ob)

Species measured: •! Various switchgrass •! Sweet and field corn

Partner: •! Horticultural Farm

CSU Ft. Collins

Syn Air

CO2

a)! Assimilation: Net uptake of CO2 b)! Stomatal conductance: how open are pores of the leaf

Leaf Cuvette Compared to Whole Plant Cuvette


Leaf cuvette (field study): •! In-field well Developed Leaves •! Leaf Level Flux Rates •! Full Control over Environ. Factors

•! High Dilution (Poor VOC Flux LOD) •! Very Fast Dynamic Enclosure

Plant cuvette (lab study): •! Potted Plants; Greenhouse Grown •! Whole Plant Flux Rates •! Limited Control over Environ. Factors •! Good Flux LOD

•! Response Time: Tens of Minutes

Syn Air

CO2

Leaf Cuvette Compared to Whole Plant Cuvette


Leaf cuvette (field study): •! Positive selection fro well developed top-of-the-canopy leaves

Plant cuvette (lab study): •! Integration over the whole plant and scaled to total leaf area

•! Data indicates that care must be taken for the upscaling of leaf level emission rates •! Methanol is strongest VOC emission from switchgrass

Drivers for Methanol Emission from Switchgrass


•! About 1/3 of MeOH flux variability can be explained by stomatal conductance. •! Different switchgrass varieties show different MeOH emission rates. •! Factors such as weather history and water availability play a role.

11..22

00..88

00..44

00..00

MMeeOO

HH EEmm

iissssiioo

nn RRaa

ttee [[

nnmmooll

mm--22

ss--11

]]

00..112200..008800..004400..0000SSttoommaattaall CCoonndduuccttaannccee [[mmmmooll mm--22 ss--11]]

MMeetthhaannooll vvss CCoonndduuccttaanncceeopen symbols: individual replicatesfull symbols: weighted averages

SG1Blackwell SG1Pathfinder SG2Blackwell SG2Pathfinder

LLiinneeaarr RReeggrreessssiioonn ((9955%% CCII))

fMeOH = k0 + k1*gs

R2 = 32%k0 = 0.16 ± 0.12k1 = 6.2 ± 2.1

linear fit 95% confidence band

Submission to Atmospheric Enivronment

special issue on Agriculture and Air Quality

will show this data.

Leaf Cuvette studies: Switchgrass vs. Corn


Comparison of emission rates: •! Corn has significantly higher VOC emissions than switchgrass

Submission to Atmospheric Enivronment special issue on Agriculture and Air Quality will

show this data.

Leaf Plant Cuvette studies: Field Corn vs. Sweet Corn


Comparison of emission rates: •! Field and sweet corn show similar VOC emission rates and patterns

Submission to Atmospheric Enivronment special issue on Agriculture and Air Quality will

show this data.

Why ecosystem flux measurement: •! No up-scaling from leaf/plant level to ecosystem necessary •! No disturbance of the plants by enclosures •! Ambient environmental factors •! Looking into both emission and uptake of VOC

Why corn field: •! Corn is still the most important biofuel crop •! Little information on VOC emissions in literature from corn or switchgrass •! Leaf cuvette studies showed much larger emissions from corn than from switchgrass

Phase 3: Ecosystem Flux Measurements


Sonic t ower:3-D sonic (RM Young)fCO2; fH2O (Licor 7500)Net radiat ion (REBS Q*7.1)

Mean dat a t ower:T; RH; WS; WD; PrsGround T & heat f lux

MABEL:CO2; H2O; phot olysisO3; NO; NO2(x2) ; CO

VOC:Acid CIMSPTR-MSTACOH

Sample manifold:1 / 2" PFA; ~15 m50-70 lpm; ~1 sec.

How to measure ecosystem flux: Eddy covariance technique

F! "w (t) # "c (t) dtT$

“Bee Farm” "! Circular field, radius 380m, irrigated

"! Day time wind: S-SSE "! Night time wind: NNW-NNE

"! Planting: Beginning of May "! Harvest: mid Nov

"! Owner: Agricultural Research Development and Education Center CSU, Ft. Collins

~171deg ~204deg Prime day time sector: 340m: 148 – 181deg

Prime night time sector: 340m: 343– 18 deg


Ecosystem Flux Measurements

Special thanks to ARDEC team: Chris Fryrear Mark Collins Karl Whitman Jennifer Bornhoft Bob Bee and the Bee family and to John Holloway (NOAA)

EcosystemFlux Measurements http://esrl.noaa.gov/csd/tropchem/biocorn2011/


•! Two towers •! Two containers Site Layout:

Photo: Eric Williams

Preparations for large-scale Flux Measurements http://esrl.noaa.gov/csd/tropchem/biocorn2011/


Photo: Eric Williams

Instruments, Time periods http://esrl.noaa.gov/csd/tropchem/biocorn2011/

Instrument Species Measured Technique PI's

Sonic anemometer 3D-Wind, T Eddy covariance Eric Williams / Brian Lerner

LiCor7500 Open-path CO2, H2O, T Eddy covariance Eric Williams / Robert Zamora

Chemiluminescence, … O3, NO, NO2, CO, CO2 Eddy covariance Eric Williams / Brian Lerner

Radiometers J values Radiation Brian Lerner

LAI "LAI meter LAI Thomas Karl / Martin Graus

PTR-MS VOCs Eddy covariance Martin Graus / Carsten Warneke

Acid CIMS Organic/inorganic acids Eddy covariance Carsten Warneke

GC-MS VOCs Mixing ratios Jessica Gilman / Carsten Warneke

LiCor 6400 plant physiology, CO2 Leaf level fluxes Allyson Eller / Martin Graus

Soil Chambers VOCs, CO2 Soil fluxes Chris Gray / Martin Graus

Cartridges samples Sesquiterpene/monoterpene gradients Gradients Detlev Helmig

Cartridges samples sesquiterpene and semivolatiles Leaf level fluxes Peter Harley


"! July: Strongest biomass increase "! August: Corn ears development

Thanks to: Emissions of Biogenic Aerosol and Ozone Precursors by Biofuel

Crops USDA 2009-35112-05217

Plant cuvette measurements: "! Switchgrass is a low VOC emitters compared to other biofuel crops

Leaf cuvette measurements: "! Corn is stronger VOC emitter than switchgrass Field flux experiment: "! Field experiment (BioCORN 2011) or fluxes from corn field July-August 2011 "! Several research groups involved

Conclusions

voc emissions from biofuel crops - agro division and air quality... · voc emissions from biofuel...

Documents