M. Jeguirim, A. Zorpas, N. Kraiem, M. Lajili, C. Guizani, Y. Leva, L. Limousy

June 25th 2016

Chemometric analysis for the relationship between mineral contents, particle matter and

bottom ash distribution during pellets combustion

The 4th International Conference onSustainable Solid Waste Management

Limassol, 23–25 June 2016

2

Context

Depletion of fossil fuel reserves

Increase of wood biomass demand

Increase of energy price

Research of new alternative biomass sources

Rapid growth in wood pellets production

Unbearable pressure on the forest and wood industries

3

Context and objective

Low quality comparing to wood pellets : high ash, nitrogen, sulphur contents :

Considerable amount of gaseous and particulate matter emissions in exhaust gases.

Objective : Relationship between pellets properties, ash composition and PM emissions

Pellets production from agriculture and agrifood industry residues

Slagging, fouling or corrosion in combustion system

44

Objectives

Pellets Production and Characterization :o Different agrifood residues : Tomato Waste, Grape Marc, Exhausted Olive Mill Solid Waste, Olive Mill Wastewater, Sawdust

o Physicochemical characteristics and energy contents

o Mineral contents Combustion tests :

o Combustion and boiler efficiencies

o Gaseous emission characteristics

o Particle Matters Emission Characterization

Chemometric analysis

o Bottom ash Characterization

5

Pellets Production and Characterization

Part I : Pellets Production and Characterization

Pellets Production

Pelletizer KAHL 15/75 Type

Pelletizer KAHL 15/75 Die diameter 6 mm, length 30 mm Frequency : 50-52 Hz Temperature : 60-70°C

6

TW

IS EOMSW IEOMSW

50 GM/50 PS50 TW/50 PS PS

7

Pellets Characterization

Parameter Unit TW TW-PS GM-PS EOMSW IEOMSW PS IS

Moisture (%, wb) 10 11 9 12 7 13 9Ash (%, db) 11 4 9 3 7 0.6 4

ρapparent (kg.m-3) 522 473 569 626 690 601 550LHVwb (MJ.kg-1) 19.5 17.6 16.6 16.3 19.8 16.4 18.5

EDpellets (GJ.m-3) 10.2 8.3 9.4 10.2 13.7 9.8 10.2N (%, wb) 1.5 0.8 1.4 0.8 1.8 0.2 1.0S (g.kg-1) 2.96 2.08 1.43 1.99 2.55 0.12 1.55K (g.kg-1) 30.48 5.14 5.15 3.67 7.53 0.36 3.40Cl (g.kg-1) 5.75 3.42 0.70 3.44 6.28 0.31 6.12Ca (g.kg-1) 1.45 1.22 1.28 1.13 1.45 0.36 0.87Si (g.kg-1) 0.19 0.18 0.21 0.09 0.21 0.01 0.16Na (g.kg-1) 0.35 0.29 0.23 0.78 1.79 0.01 1.15P (g.kg-1) 0.93 0.64 0.36 0.13 0.23 0.08 0.18

Mg (g.kg-1) 0.59 0.45 0.22 0.12 0.22 0.02 0.16Al (g.kg-1) 0.12 0.11 0.20 0.05 0.13 0.01 0.09Fe (g.kg-1) 0.10 0.10 0.12 0.04 1.00 0.02 0.90Mn (g.kg-1) 0.09 0.01 0.01 0 0.01 0.05 0.02

8

Combustion Experiments

Part II : Combustion Experiments

9

Combustion Experiments

Combustion tests performed with a residential boiler :

Boiler – 12 kW (Ökofen)Portable analyzer

(TESTO 350XL)

ELPI (Dekati)

10

Combustion Experiments

Sampleq

(kg h-1)λ

ηcomb ηboil O2 CO2 CO NOx VOC PM

(%) (%) (mg.Nm-3) at 10%O2

TW 2.60 2.10 88.9 80.6 12.1 8 495 428 566 2719

TW-PS 2.40 2.90 87.3 81.1 13.7 7 809 537 515 2279

GM-PS 2.30 4.70 90.4 80.2 16.6 5 631 456 602 966

EOMSW 2.70 2.40 88.4 83.7 12.3 8 993 384 777 558

IEOSW 2.00 2.07 91.5 84.9 10.9 9 631 223 491 1038

PS 2.1 2.61 91.0 83.4 15.0 6 346 116 914 143

IS 2.3 2.35 88.2 81.8 12.1 8 1022 255 1207 659

11

Characterization of PM Emissions

0

300

600

900

1200

1500

<0,1 µm 0,1-0,25µm 0,25-1µm 1-2,5µm >2,5µm

Part

icle

con

cent

ratio

ns (m

g/N

m3 )

Particle size

TWTW-PSGM-PSEOMSWIEOMSWPSIS

12

Characterization of PM Emissions

0

20

40

60

80

<0,1 µm 0,1-0,25µm 0,25-1µm 1-2,5µm >2,5µm

Part

icle

mas

s (%

)

Particle size

TWTW-PSGM-PSEOMSWIEOMSWPSIS

13

Bottom Ash Characterization

Element PS IS EOMSW IEOMSW TW TW-PS GM-PS

K2O 18.68 30.99 27.35 28.27 26.84 26.00 25.32SiO2 8.62 6.93 19.44 21.97 9.42 12.64 32.50CaO 40.03 15.34 29.81 18.33 17.88 22.19 18.26

Fe2O3 7.52 10.65 2.09 9.64 1.86 2.11 2.30SO3 1.99 3.60 4.47 5.08 3.56 3.64 2.42P2O5 3.22 3.81 5.01 4.23 16.22 16.03 5.39Na2O 2.04 4.05 3.75 4.09 2.32 2.50 1.81MgO 3.31 2.68 3.43 2.85 10.10 11.08 3.69

Cl 1.18 7.90 2.39 2.72 1.51 0.75 0.19Al2O3 1.84 1.54 1.57 2.23 1.88 2.54 5.97TiO2 0.20 0.13 0.18 0.25 0.06 0.07 0.16SrO 0.11 0.02 0.25 0.15 0.13 0.14 0.07CuO - 0.12 0.11 0.07 - - -Cr2O3 - - 0.12 0.05 - - -ZrO2 0.01 - - 0.04 - - -ZnO 0.04 0.03 - 0.03 - 0.03 -Rb2O 0.04 0.02 0.01 0.01 - 0.01 -MnO2 0.88 0.48 - - 0.22 0.23 -

Br - 0.02 - - - - -Sum - - 100 100 100 100 100

14

Bottom Ash Characterization

0

20

40

60

80

100

0 100 200 300 400 500

P (%

)

Size (µm)

PSTW-PSISTWEOMSWIEOMSWGM-PS

15

Chemometric Analysis

Part III: Chemometric Analysis

16

Chemometric Analysis

0K

0

Na

0

P

0

Mn

0

Fe

0 Mg0

Si

0

Ca

0

Al

0

Cl

0

S

0

K/Si

0

Cl/K

0

Cl/Si

0

<0,1 µm

0

0,1‐1µm

0

1‐2,5µm

0

>2,5µm

0

Tot

‐1

‐0,5

0

0,5

1

-1 -0,5 0 0,5 1

--ax

is F

2 (2

1,26

%) -

->

-- axisF1 (51,30 %) -->

17

Chemometric Analysis

y = 0,686x + 28,659R² = 0,9349

0

10

20

30

40

50

60

70

0 10 20 30 40 50

% b

otto

m a

sh si

ze >

500

µm

(K + Si )molar fraction

18

Conclusions

Pellets produced from agriculture and agrifood industriesresidues are promising to reduce pressure on wood markets.

Drawbacks : increase of PM emissions and ash depositionand agglomeration during combustion.

PM emissions were dominated by PM 1 (0.25-1µm). Theseemissions were affected the presence of K, Na and Cl andcorrelated to the K/Si molar ratio

PM emissions increase significantly for higher K/Si ratio.For lower K/Si ratio, K is retained by Si in the bottom ash.

Low ash content and the presence of Ca lead to ahomogenous bottom ash with lower particle size.

High ash content and the presence of K and Si lead to anagglomerated bottom ash with large particles

M. Jeguirim, A. Zorpas, N. Kraiem, M. Lajili, C. Guizani, Y. Leva, L. Limousy

June 25th 2016

Chemometric analysis for the relationship between mineral contents, particle matter and

bottom ash distribution during pellets combustion

The 4th International Conference onSustainable Solid Waste Management

Limassol, 23–25 June 2016