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IEA Bioenergy Task 32 14 July 2017

Thomas Nussbaumer

Verenum Research, ZürichLucerne University of ASAIEA Bioenergy Task 32

The Advanced Bioeconomy Leadership ConferenceHotel Nikko, San Francisco, CA, USA, 6.-9. November 2018

http://biofuelsdigest.com/ablcglobal/

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Aerosols from Biomass Combustion

Part 1: Background

1.1 Suppositions, facts and figures

1.2 Measures to reduce or avoid PM

Part 2: Position of IEA Task 32

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Aerosols from Biomass Combustion

Part 1: Background

1.1 Suppositions, facts and figures

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[OECD/IEA: Energy Poverty, IEA, Paris 2010]

Mio

dea

ths

per y

ear

Aerosols from Biomass Combustion Part 1: Background1.  Priority 1 for IEA Bioenergy is to promote biomass as a renewable fuel,

however, only for applications with low environmental impact


2.  Good boilers cause low air pollution if they are properly operated

3.  Non-ideal devices or operation cause incomplete combustion and PIC: 
– gases (CO, VOC) and 
– particulate matter (PM)

4.  Epidemiology reveals that inhalable PM (PM10, 2.5, …) is harmful to health

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Aerosols from Biomass Combustion Part 1: Background1.  Priority 1 for IEA Bioenergy is to promote biomass as a renewable fuel,

however, only for applications with low environmental impact


2.  Good boilers cause low air pollution if they are properly operated

3.  Non-ideal devices or operation cause incomplete combustion and PIC: 
– gases (CO, VOC) and 
– particulate matter (PM)

4.  Epidemiology reveals that inhalable PM (PM10, 2.5, …) is harmful to health

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Target conflict

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Aerosols from Biomass Combustion Part 1: Background1.  Priority 1 for IEA Bioenergy is to promote biomass as a renewable fuel,

however, only for applications with low environmental impact


2.  Good boilers cause low air pollution if they are properly operated

3.  Non-ideal devices or operation cause incomplete combustion and PIC: 
– gases (CO, VOC) and 
– particulate matter (PM)

4.  Epidemiology reveals that inhalable PM (PM10, 2.5, …) is harmful to health

5.  To assess combustion aerosols, two types of PM are distinguished


Type 1: Products from incomplete combustion (carbonaceous) 
 causing a) primary PM as soot and POA (incl. COC (tar))


b) SOA formed from VOC


Type 2: Products also formed at near-complete combustion: 
Primary inorganic aerosols from ash (K, Ca, Cl, ..)
Thanks to lack of OC, these “salts” can be precipitated

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CaCO3

u > 0.1 m/s

Ash CaCO3

> 1–10 µm

Evaporation Entrainment

G a s p h a s e p o l l u t a n t s S o l i d P a r t i c u l a t e M a t t e r Droplets Gas

CxHyOz

H2O

K, Na, Ca, S, Cl, N

H2O

T > 100°

Devolatilisation Pyrolysis C (Char)

CmHn CO, H2

T > 300° + O2

+O2 +CO2

Gasification

CO

VOC COC

τ >

Primary Tars

τ <

O2 = 0

T > 550°

+O2 T > 800°

+O2

CO2 CO

Gas phase combustion

Sol

id fu

el c

onve

rsio

n

in fu

el b

ed

by p

rimar

y ai

r

Con

secu

tive

reac

tions

in

com

bust

ion

cham

ber

by s

econ

dary

air

Chi

mne

y

NOX

Secondary Tars

>700°

PAH

T > 800° T < 800° O2 = 0

–H2

Soot (BC)

< 100 nm

+O2 +O2

Evaporation

Nucleation

Coagulation

KCl, K2SO4 oxides

< 100 nm

T > 800°

Condensation

K+, Na+, Cl–, SO42–, OH–, CO32–, NO3–

Zn-, Mg-, Fe-, Al-oxides Waste: Cu, Cr, Pb, (Cd)

Salts

u Gas velocity, τ Residence time, short/long 1 Solid-particle-path, 2 Solid-vapour-particle-path

1 2

BC: Black Carbon COC: Condensable Organic Compounds VOC: Volatile Organic Compounds

Data on T: [Evans and Milne, 1987] on H2: [Jess, 1996]

Biomass + Char

u > 0.1 m/s

> 10 µm

Products from Complete

Combustion

Products from Incomplete Combustion (PIC)

Products from Complete

Combustion

[Nussbaumer, T., IEA Report 2017]

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G a s p h a s e p o l l u t a n t s S o l i d P a r t i c u l a t e M a t t e r Droplets Gas H2O VOC COC CO2 CO

Chi

mne

y

NOX Soot (BC) Salts

Biomass + Char

Chi

mne

y

A t m o s p h e r ePOA + EC/BC

PM10SOAPIA SIA

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G a s p h a s e p o l l u t a n t s S o l i d P a r t i c u l a t e M a t t e r Droplets Gas H2O VOC COC CO2 CO

Chi

mne

y

NOX Soot (BC) Salts

Biomass + Char

Chi

mne

y

A t m o s p h e r ePOA + EC/BC

PM10SOAPIA SIA

54321010

100

1 000

10 000

100 000

λ

[mg/Nm3] (11% O2)

[ – ]

CO

Excess Air Ratio λ

[Nussbaumer, T., Energy & Fuels, Vol. 17, No 6, 2003, 1510–1521, 17]and 
[Lauber, A., Nussbaumer, T., 
13th ETH-Conf. on Comb. Gen. Nanop., June 22 – 24 2009, Zurich

A (Type 1)

B (Type 2)

C (Type 1)

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G a s p h a s e p o l l u t a n t s S o l i d P a r t i c u l a t e M a t t e r Droplets Gas H2O VOC COC CO2 CO

Chi

mne

y

NOX Soot (BC) Salts

Biomass + Char

Chi

mne

y

A t m o s p h e r ePOA + EC/BC

PM10SOAPIA SIA

[Schmid AG]

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G a s p h a s e p o l l u t a n t s S o l i d P a r t i c u l a t e M a t t e r Droplets Gas H2O VOC COC CO2 CO NOX

Soot (BC) Salts

Biomass + Char

Pro-inflammatory cytokines TNF-α and interleukin 8 as a function of the organic content of smoke from tunnel, diesel and wood [Kocbach, A. et al., Toxicology 2008, 247 (2–3), 123-132]

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SOAPOA + EC/BCPIA

Incidators for Health effects as function of Organic Carbon in Smoke

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G a s p h a s e p o l l u t a n t s S o l i d P a r t i c u l a t e M a t t e r Droplets Gas H2O VOC COC CO2 CO NOX

Soot (BC) Salts

Biomass + Char

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SOAPOA + EC/BCPIA

[Klippel, N.; Nussbaumer, T., 15th Eur. Biomass Conf. Berlin 7–11 May 2007]

Soot from Diesel engine

Salt particles from automated wood boiler

Soot + COC from badly operated wood stove

50%

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G a s p h a s e p o l l u t a n t s S o l i d P a r t i c u l a t e M a t t e r Droplets Gas H2O VOC COC CO2 CO NOX

Soot (BC) Salts

Biomass + Char

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SOAPOA + EC/BCPIA

Aged ROS as function of Aged OA

left [Baltensperger, U., 11. Holzen.-Symp., Zürich 2010, www.holzenergie-symposium.ch]
right [Zhou, J. et al., Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-1068, 2017]

LAC-PSI literature 
(not in IEA report):

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Aerosols from Biomass Combustion

Part 1: Background

1.1 Suppositions, facts and figures

1.2 Measures to reduce or avoid PM

Part 2: Position of IEA Task 32

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Aerosols from Biomass Combustion

Measures to reduce PM or avoid increased PM

Primary Measures: Complete combustion 


1.  Appropriate air-fuel ratio + T T T


2.  Avoid non-ideal conditions:
- ideal start-up 
- ...

Type 1 (PIC)

[1] Nussbaumer, T. et al., 16th EUBCE, Valencia, 2008[2] Good, J. et al., 11. Holzenergie-Symposium, Zürich 2010

[1]

[2]

[1]

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Aerosols from Biomass Combustion

Measures to reduce PM or avoid increased PM

Primary Measures: Complete combustion 


1.  Appropriate air-fuel ratio + T T T


2.  Avoid non-ideal conditions:
- ideal start-up 
- fuel moisture and size 
- reasonable burn rate 
- no air throttling 
- ...

Type 1 (PIC)

[1] Hartmann, H. et al., IEA T32 Session at ETH Conf. 2016

[1]

[1]

[2]

[2] Seljeskog, M. et al., IEA T32 Session at ETH Conf. 2016

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Aerosols from Biomass Combustion

Measures to reduce PM or avoid increased PM

Primary Measures: Complete combustion 


1.  Appropriate air-fuel ratio plus T T T 


2.  Avoid non-ideal conditions:
- ideal start-up 
- fuel moisture and size 
- reasonable burn rate 
- no air throttling 


Secondary measures: catalytic oxidation & precipitation 
only as add-on due to limited availability and drawbacks

Type 1 (PIC)

Primary meas.: Low ash fuels for small devices (harvest, sieving)Secondary m.: Precipitation for autom. boilers (with low PIC) 
 For RWC optionally, however critical for high PIC

Type 2 (salts)

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Aerosols from Biomass Combustion

Part 1: Background

1.1 Suppositions, facts and figures

1.2 Measures to reduce or avoid PM

Part 2: Position of IEA Task 32 


7 statements agreed by 13 member countries

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Aerosols from Biomass Combustion 1.  Mortality due to cooking on open fires shall be reduced by gasifier

stoves or alternatives (gas, solar, el.)

2.  For manually operated devices, an appropriate operation is crucial,
secondary measures are only considered as an add-on

3.  Standardisation of fuels, devices, and test methods 
can assist target-oriented development 


4.  Automated plants for heat and/or power with advanced design and control achieve 
- very low organic pollutants and 
- enable efficient precipitation of inorganic particles

5.  Task 32 supports automated boilers with control and precipitation.

6.  Future regulations should distinguish between organic and inorganic particles and take into account secondary organic aerosol 


7.  An exchange between research, industry, and authorities can assist advancements to promote biomass and prevent PM

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INHALT Kapitel 1

Acknowledments

IEA Bioenergy Task 32

Swiss Federal Office of Energy 


Federal Office for the Environment

Swiss National Science Foundation

SCCER Biosweet and Innosuisse 


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The End

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10

100

1 000

10 000

100 000

λ

[mg/Nm3] (11% O2)

[ – ]

CO

COCSoot

Salts

[Nussbaumer, T., Energy & Fuels, Vol. 17, No 6, 2003, 1510–1521, 17] Excess Air Ratio λ

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1-stage Combustion

Problem 2:
Mixing air + gas

Problem 3:
Air leakage

Problem 5:
Quenching

Problem 4:
Flame cooling

Problem 1:
Air/fuel ratio

Air

Nat

ural

dra

ugt

Diffusion flame

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2-stage Combustion

Hoval

Premixed flame

[Nussbaumer, Energy & Fuels, Vol. 17, No 6, 2003, 1510–1521, 17]

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Under Stoker Boiler

4

P2P1 P3

20 kW ... 2000 kW 200 kW ... 10 MW

Moving grate Furnace

[Nussbaumer, T., Energy & Fuels, Vol. 17, No 6, 2003, 1510–1521, 17]

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Example of 6.4 MW District heating plant

Graph by Schmid AG, plant in Wilderswil (Interlaken)

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Fluidized Bed Combustionstationary

5 – 100 MW

[Lurgi]

circulating20 – 100 MW

[Ahlstom]

– High turbulence

– Air staging

– Circulation of inertbed material (sand, ash)

Temperature controlby heat extraction