GASIFICATION OF BIOMASS CHAR OBTAINED VIA PYROLYSIS

GASIFICATION OF BIOMASS

CHAR OBTAINED VIA PYROLYSIS

D. López-González, M. Fernández-López, J.L. Valverde and L. Sánchez-Silva1*

Department of Chemical Engineering. University of Castilla-La Mancha. Spain

Renewable Energies

Biomass

Air Pollution

Global Warming

1

Introduction

Non food crops

Biomass: “Any organic material that stems from plants including algae, trees and crops that are susceptible to be converted into energy””

Energy vector

Dedicated biomass crops

2

McKenry. Bioresour Technol.. (2002)

Introduction

o Terrestrial biomass (lignocellulosic)

Types of biomass

o Marine biomass (Algae)

Natural biomass Residual biomass Energy crops

Microalgae Macroalgae

Short growing period High yields No competition with

food crops

o Thermochemical processes

Energy conversion of biomass

o Biochemical processes

• Liquefaction

• Hydrothermal treatment

• Alcoholic fermentation

• Anaerobic digestion

• Pyrolysis

• Combustion

• Gasification

3

Introduction

Gasification: Is a thermochemical process consisting on the conversion of biomass to a gaseous fuel by heating in a gasification medium such as air, oxygen or steam

C + O2 CO2 (complete combustion)

C + 1/2O2 CO (incomplete combustion)

C + H2O CO + H2 (steam reaction)

Thermal Analysis has been widely used for the study of biomass conversion processes

Evolved gas analysis (EGA)

• Fourier transform infrared spectroscopy (FTIR)

• Gas cromatography (GC)

• Mass spectrometry (MS)

It is the only experimental technique to measure in real time the thermal decomposition and the gas product distribution of a very small sample.

5

Introduction

Comprehensive study of the gasification process of different types of lignocellulosic biomass by means of TGA–MS technique

Aim of this work

6

TGA evaluation of gasification process

Aim of this work:

Study of the evolved gases

Kinetic study of the gasification process

FIC

FIC

Bubble

Flow meter

Thermobalance (TGA)

Mass

spectrometer

(MS)

N2

CO2

O2

He

TGA Flow meter

Bubbling system

01

O 1

Ar

PC

PC

Feeding system

Reacting system

7

Analysis system

Experimental setup & Methodology

Bubbling system

8

The methodology employed was as follow:

Biomass samples:

oBiomass main components:

o Lignocellulosic biomass:

• Cellulose • Hemicellulose (Xylan) • Lignin

• Eucalyptus wood • Fir wood • Pine bark

Experimental conditions

Pyrolysis stage

Drying stage 30 ºC-105 ºC

Temperature Range 105-1000 ºC

Heating rate 40 ºC min-1

Flow gas 200 Nml min-1

Atmosphere Ar

Sample size 20 mg

Gasification stage

Temperature 900 ºC

Flow gas 50 Nml min-1

Carrier gas Ar

Gasifying agent Steam (5 vol.%)


Characterization of biomass samples

TGA analysis

Evolved gas analysis

Kinetic analysis

1) Evaluation of the gasification process of biomass char obtained via pyrolysis.

8

9

Partial objectives


TGA analysis


Kinetic analysis


8

10

Partial objectives

11

Biomass composition:

Biomass sample Cellulose (wt.%)

Lignin (wt.%)

Hemicellulose (wt.%)

Extractives (wt.%)

Cellulose 100 - - -

Lignin - 100 - -

Xylan - - 100 -

Eucalyptus wood 52 17 24 7

Fir wood 38 24 30 8

Pine bark 13 31 37 19

Characterization of Biomass Samples

Cellulose: Lignin: Pine > Fir > Eucalyptus

Hemicellulose: Pine > Fir > Eucalyptus

Extractives:

Eucalyptus > Fir > Pine

Pine > Fir > Eucalyptus

13

Proximate analysis: The proximate analyses determine the energetic content of biomass samples

Biomass sample Moisture (MC)

Ash (AC)

Volatile matter (VM)

Fixed Carbon (FC)

Cellulose 3.0 0.8 90.7 6.0

Lignin 1.1 3.7 55.8 39.3

Xylan 6.4 2.8 71.6 19.2

Eucalyptus wood 2.6 6.8 73.8 16.8

Fir wood 2.6 3.4 74.4 19.5

Pine bark 4.4 2.7 61.6 31.3


Standard Procedure Volatile matter (VM): UNE-EN 15148 Ash content (AC): UNE-EN 14775 Moisture content (MC): UNE-EN 14774 Fixed Carbon*dab = 100 – (VM+AC+MC)*dab

Moisture content: Similar for all samples

Ash content: Eucalyptus > Lignin > Fir >Xylan > Pine > Cellulose

Volatile matter:

Fixed carbon:

Cellulose > Fir > Eucalyptus > Pine > Xylan > Lignin

Lignin > Pine > Fir > Xylan > Eucalyptus > Cellulose

14

Mineral content:

Mineral content (ppm)

Biomass sample Al Ca Fe K Mg Na Ni P Si

Cellulose 367 2711 106 575 255 1476 980 6869 237816

Lignin 500 868 126 1069 219 7197 758 6100 181504

Xylan 213 4343 77 456 124 13828 382 3326 68856

Eucalyptus wood 43 4116 33 5078 1062 1431 51 7819 247227

Fir wood 557 10921 717 1880 1774 1807 27 8608 353166

Pine bark 946 2726 385 1254 776 2764 463 7360 474344


High presence of alkali and alkali-earth metals: K, Ca, Mg or Na

Elevated concentration of Si and Al

Contribution to the appearance of slagging and fouling phenomena

Perform as catalyst/inhibitors of thermochemical conversion processes

Inductively coupled plasma (ICP) (Liberty Sequential. Varian)


TGA analysis


Kinetic analysis


8

15

Partial objectives

0 25 50 75 100 125 1500

20

40

60

80

100

Pyrolysis

Weig

ht

(wt.

%)

Time (min)

Cellulose

Lignin

Xylan

Steam Gasification

200

400

600

800

1000

1200

Temperature

Tem

pera

ture (

ºC)

17

Thermogravimetric Analysis

0 5 10 15 200

40

80

Temperature (ºC)

Weig

ht

loss

ra

te (

wt.

%/

min

)

Time (min)

Lignin

Xylan

Cellulose

125 250 375 500 625 750 875

Pyrolysis

Pyrolysis temperature range: 200 – 700 ºC

One decomposition step (220-500 ºC)

Maximum weight loss rate

Char yield: 10 wt.%

Cellulose: Xylan:

Least thermally stable component

Decomposition temperature range: 200-375 ºC

Two decomposition peaks at 262 and 306 ºC

Lignin:

Char yield: > 40 wt.%

Decomposition over the whole temperature range

(215-700 ºC)

Biomass main components

0 25 50 75 100 125 1500

20

40

60

80

100

Pyrolysis

Weig

ht

(wt.

%)

Time (min)

Cellulose

Lignin

Xylan

Steam Gasification

200

400

600

800

1000

1200

Temperature

Tem

pera

ture (

ºC)

18


0 10 20 30 40 50 60 700

1

2

3

4

5

6

Steam Gasification

Weig

ht

loss

ra

te (

wt.

%/

min

)

Time (min)

Lignin

Xylan

Cellulose

Lignin: 29 min

Xylan: 26 min

Cellulose: ~120 min

Full char gasification

Lignin

Cellulose Xylan

Biomass main components

0 25 50 75 100 125 150

0

20

40

60

80

100

0 3 6 9 12 150

5

10

15

20

25

30

0 20 40 60 80 100 1200

1

2

3

4

5

6

Pyrolysis Steam Gasification

Pyrolysis

Wei

gh

t (w

t.%

)

Time (min)

Pine bark

Fir wood

Eucalyptus wood

Steam Gasification

200

400

600

800

1000

1200

Temperature

Tem

per

atu

re (

ºC)

Wei

gh

t lo

ss r

ate

(w

t. %

/ m

in)

Time (min)

b)i)

iii)ii)

Wei

gh

t lo

ss r

ate

(w

t. %

/ m

in)

Time (min)

900

1000

1100

Tem

per

atu

re (

ºC)

200 300 400 500 600 700

Temperature (ºC)

a)

b)

DTGDTG

DTGDTG

19


Pyrolysis temperature range: 200 – 700 ºC

Lignocellulosic biomass

0 25 50 75 100 125 1500

20

40

60

80

100

Pyrolysis

Weig

ht

(wt.

%)

Time (min)

Pine bark

Eucalyptus wood

Fir wood

Steam Gasification

200

400

600

800

1000

1200

Temperature

Tem

pera

ture (

ºC)

Lignocellulosic biomass:

Shoulder: ≈ 300 ºC Hemicellulose decomposition

Tail: > 400 ºC Lignin decomposition

Maximum decomposition peak: 350-370 ºC Cellulose decomposition

Char yield (wt.%)

25

Fir wood

Pine bark

Eucalyptus wood

24

35

0 25 50 75 100 125 150

0

20

40

60

80

100

0 3 6 9 12 150

5

10

15

20

25

30

0 20 40 60 80 100 1200

1

2

3

4

5

6

Pyrolysis Steam Gasification

Pyrolysis

Wei

gh

t (w

t.%

)

Time (min)

Pine bark

Fir wood

Eucalyptus wood

Steam Gasification

200

400

600

800

1000

1200

Temperature

Tem

per

atu

re (

ºC)

Wei

gh

t lo

ss r

ate

(w

t. %

/ m

in)

Time (min)

b)i)

iii)ii)

Wei

gh

t lo

ss r

ate

(w

t. %

/ m

in)

Time (min)

900

1000

1100

Tem

per

atu

re (

ºC)

200 300 400 500 600 700

Temperature (ºC)

a)

b)

DTGDTG

DTGDTG

0 25 50 75 100 125 1500

20

40

60

80

100

Pyrolysis

Weig

ht

(wt.

%)

Time (min)

Pine bark

Eucalyptus wood

Fir wood

Steam Gasification

200

400

600

800

1000

1200

Temperature

Tem

pera

ture (

ºC)

20


Lignocellulosic biomass

Fir wood: 35 min

Eucalyptus wood: 20 min

Pine bark: ~120 min

Full char gasification

Fir wood

Pine bark

Eucalyptus wood

Gasification rates cannot be described according to their initial biochemical

composition

0.0

1.5

3.0

4.5

6.0

7.5

0.0 0.2 0.4 0.6 0.8 1.00.0

0.5

1.0

1.5

0.0

1.5

3.0

4.5

6.0

7.5

0.0 0.2 0.4 0.6 0.8 1.00.0

0.5

1.0

1.5

2.0

2.5

Ga

sifi

cati

on

ra

te (

1/m

in)

Rea

ctiv

ity

(1

/min

)

Conversion (X)

Cellulose

Xylan

Lignin

Ga

sifi

cati

on

ra

te (

1/m

in)

Rea

ctiv

ity

(1

/min

)

Conversion (X)

Eucalyptus wood

Fir wood

Pine bark

21

Peaks in gasification rates profile

Sudden increase of Reactivity at high conversion values

Catalytic effect of ashes

Cellulose Pine bark

Decreasing profile

Moderate rise of Reactivity

at high conversion values

Low catalytic effect of ashes


1

wi

dw dt

1

1-wi

Ri= - = dxi

dt

wi: mass at time = t xi: conversion at time = t

ri= dxi

dt

22

A.I. = Ash (wt.%) (CaO+K2O+MgO+Na2O+Fe2O3)

(SiO2+Al2O3)

t x100 t x50 R50 A.I.

Cellulose 123.8 42.8 0.026 0.017

Lignin 29.5 13.6 0.086 0.193

Xylan 26.4 9.8 0.097 0.798

Fir wood 35.4 17.4 0.057 0.164

Eucalyptus wood 19.5 10.4 0.101 0.322

Pine bark 123.3 39.8 0.023 0.045

A.I. R.

Alkali Index (A.I.)


Evaluation of catalytic efficiency of ashes: Catalytic nature

Non-Catalytic nature

The gasification of lignocellulosic biomass char is more influenced by the mineral matter in the ash than by their initial composition


TGA analysis


Kinetic analysis


8

23

Partial objectives

24

Kinetic analysis

dα dt

= k (T,Pw) f(α)

Kinetic expression:

Apparent gasification rate

Reaction mechanism

Volumetric model (VM)

Shrinking core model (SCM)

Random pore model (RPM)

VBA-Excel application

Runge-Kutta-Fehlberg

f(α)= (1-α)

f(α)= (1-α)2/3

f(α)= (1-α) 1-Ψ ln(1- α)

Parameter related with the initial pore structure of the sample

Statistical significance

Model statistical significance: F-test

Parameter statistical significance: t-test

25

VM led to the worst fitting

Error (%) VM SCM RPM

Cellulose 6.8 5.1 1.1

Lignin 31.7 22.5 8.9

Xylan 19.0 10.5 8.8

Fir wood 17.7 11.8 8.8

Eucalyptus wood

18.9 12.9 9.3

Pine bark 13.7 2.6 1.2

High error for X > 0.8

Low error for cellulose and pine bark

Similar errors for SCM and RPM

SCM, RPM, VPM do not consider the catalytic

effect of ashes at high conversion values

Kinetic analysis

0 15 30 45 60 75 90 105 120

0.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30

0.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30 35

0.0

0.2

0.4

0.6

0.8

1.0

0 10 20 30

0.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30

0.0

0.2

0.4

0.6

0.8

1.0

0 15 30 45 60 75 90 105 120

0.0

0.2

0.4

0.6

0.8

1.0

Co

nv

ersi

on

(x

)

Celulosa

Co

nv

ersi

on

(x

)

Time (min)

Lignina

Co

nv

ersi

on

(x)

Xilano

Abeto

Time (min)

Eucalipto

Experimental

VM

SCM

RPM

PinoCellulose Pine bark

Xylan Fir wood

Lignin Eucalyptus wood

26

Semi-empirical model based on SCM:

dα dt

= k (T,Pw) (1-α)2/3+ ka α

na

Error (%)

Lignin 0.1

Xylan 0.1

Fir wood 0.3

Eucalyptus wood

0.7

0 1 2 3

0.00

0.02

0.04

0.06

0.08

0.10

0 5 10 15

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Ka

[K]

na

[Ca]

na= 0.254 [Ca] + 3.4 10-2

r2=0.9699

dα

dt = k (T.Pw) (1-α)2/3+ ka α

0.254 [Ca] + 3.4 10-2

Kinetic analysis

0 5 10 15 20 25 30

0.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20

0.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30 35

0.0

0.2

0.4

0.6

0.8

1.00 5 10 15 20

0.0

0.2

0.4

0.6

0.8

1.0

Con

ver

sion

(x)

Lignina

Tiempo (min)

Madera de Eucalipto

Con

ver

sion

(x)

Tiempo (min)

Madera de Abeto

Experimental

Teórico

XilanoXylan Lignin

Eucalyptus wood

Experimental

Theoretical

Fir wood

Time (min) Time (min)

Biomass

samples

Model Parameters tc ttest Fc Ftest Error (%)

Cellulose

VM 1.71 76 24723 3.84 6.8

SCM k (min-1

)(∙102) 1.48 55059 1.96 175522 3.84 1.1

RPM 1.21 69809 32677 3.00 5.1

Ψ 1.9 13991

Lignin

VM 5.58 2251 1602 3.84 31.7

SCM k (min-1

)(∙102) 4.48 98519 1.96 7025 3.84 22.5

RPM 2.14 38039 20194 3.00 8.9

Ψ 20.7 30254

Xylan

VM 8.81 2265 36796 3.84 19.0

SCM k (min-1

)(∙102) 7.32 89 1.96 110675 3.84 10.5

RPM 2.49 204 217283 3.00 8.8

Ψ 33.5 25350

Fir wood VM 3.31 60942 1102 3.84 17.7

SCM k (min-1

)(∙102) 3.98 10221 1.96 9177 3.84 11.8

RPM 2.29 20953 32749 3.00 8.8

Ψ 7.3 15236

Eucalyptus

wood

VM 6.26 4715 6744 3.84 18.9

SCM k (min-1

)(∙102) 7.23 64 1.96 44861 3.84 12.9

RPM 3.79 4458 73100 3.00 9.3

Ψ 10.2 27593

Pine bark

VM 2.08 1343 11357 3.84 13.7

SCM k (min-1

)(∙102) 1.67 10011 1.96 132563 3.84 2.6

RPM 1.46 301 32128 3.00 1.2

Ψ 1.8 294

27

Kinetic analysis

Biomass

samples

Parameter tc ttest Fc Ftest Error

(%)

Lignin ka 1.54∙10-2

141 1.96 5282310 2.37 0.1

na 0.94 221

Xylan ka 3.55∙10-2

100 1.96 37838 2.45 0.1

na 0.67 36

Fir wood ka 2.56∙10-2

3702315 1.96 1431060 2.37 0.3

na 0.76 80

Eucalyptus

wood

ka 4.92∙10-2

152 1.98 199429 2.45 0.7

na 0.43 13

Statistical Significance:

Fci model> F-test Model significance

tci-model > t-test Parameters significance

TGA analysis



Kinetic analysis


8

28

Partial objectives

29

Evolved gas analysis. Gasification

0 40 80 120

0,00

0,05

0,10

0,15

0,20

0,25

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Cellulose

0 20 40 60 80 100 120

0,0

0,1

0,2

0,3

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Pine bark

0 10 20 30 40

0,0

0,5

1,0

1,5

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Xylan

0 10 20 30 40

0,0

0,5

1,0

1,5

CO2

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Fir wood

0 10 20 30 40 50

0,0

0,5

1,0

1,5

CO

H2

CO2

Lignin

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

0 10 20 30

0

1

2

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar m

g))

*10

-4

CO

Eucalyptus wood

0 40 80 120

0,00

0,05

0,10

0,15

0,20

0,25

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Cellulose

0 20 40 60 80 100 120

0,0

0,1

0,2

0,3

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Pine bark

0 10 20 30 40

0,0

0,5

1,0

1,5

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Xylan

0 10 20 30 40

0,0

0,5

1,0

1,5

CO2

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Fir wood

0 10 20 30 40 50

0,0

0,5

1,0

1,5

CO

H2

CO2

Lignin

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

0 10 20 30

0

1

2

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar m

g))

*10

-4

CO

Eucalyptus wood

0 40 80 120

0,00

0,05

0,10

0,15

0,20

0,25

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Cellulose

0 20 40 60 80 100 120

0,0

0,1

0,2

0,3

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Pine bark

0 10 20 30 40

0,0

0,5

1,0

1,5

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Xylan

0 10 20 30 40

0,0

0,5

1,0

1,5

CO2

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Fir wood

0 10 20 30 40 50

0,0

0,5

1,0

1,5

CO

H2

CO2

Lignin

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

0 10 20 30

0

1

2

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar m

g))

*10

-4

CO

Eucalyptus wood

0 40 80 120

0,00

0,05

0,10

0,15

0,20

0,25

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Cellulose

0 20 40 60 80 100 120

0,0

0,1

0,2

0,3

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Pine bark

0 10 20 30 40

0,0

0,5

1,0

1,5

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Xylan

0 10 20 30 40

0,0

0,5

1,0

1,5

CO2

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Fir wood

0 10 20 30 40 50

0,0

0,5

1,0

1,5

CO

H2

CO2

Lignin

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

0 10 20 30

0

1

2

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar m

g))

*10

-4

CO

Eucalyptus wood

0 40 80 120

0,00

0,05

0,10

0,15

0,20

0,25

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Cellulose

0 20 40 60 80 100 120

0,0

0,1

0,2

0,3

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Pine bark

0 10 20 30 40

0,0

0,5

1,0

1,5

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Xylan

0 10 20 30 40

0,0

0,5

1,0

1,5

CO2

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Fir wood

0 10 20 30 40 50

0,0

0,5

1,0

1,5

CO

H2

CO2

Lignin

CO2

H2

Time (min)In

ten

sity

(A

/(m

bar

mg))

*10

-4

CO

0 10 20 30

0

1

2

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar m

g))

*10

-4

CO

Eucalyptus wood

0 40 80 120

0,00

0,05

0,10

0,15

0,20

0,25

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Cellulose

0 20 40 60 80 100 120

0,0

0,1

0,2

0,3

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Pine bark

0 10 20 30 40

0,0

0,5

1,0

1,5

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Xylan

0 10 20 30 40

0,0

0,5

1,0

1,5

CO2

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

Fir wood

0 10 20 30 40 50

0,0

0,5

1,0

1,5

CO

H2

CO2

Lignin

CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-4

CO

0 10 20 30

0

1

2

H2

CO

CO2CO2

H2

Time (min)

Inte

nsi

ty (

A/(

mb

ar m

g))

*10

-4

CO

Eucalyptus wood

MS spectra correlates with Reactivity ones showing maximums that are correlated with the activity of the metals in the ashes

Main gasification products: H2, CO and CO2 MS profiles.

30


0 40 80 120

0,0

0,4

0,8Cellulose

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 20 40 60 80 100 120

0,00

0,05

0,10

Pine bark

COOH

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40

0

1

2

3

4

Xylan

COOH

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,3

0,6

0,9

Fir wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

COOHNO

CH4

NO2

H2S

HS

C2H

2

SO2

SO

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

Lignin

0 20 40

0,0

0,5

1,0

Eucalyptus wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 40 80 120

0,0

0,4

0,8Cellulose

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 20 40 60 80 100 120

0,00

0,05

0,10

Pine bark

COOH

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40

0

1

2

3

4

Xylan

COOH

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,3

0,6

0,9

Fir wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

COOHNO

CH4

NO2

H2S

HS

C2H

2

SO2

SO

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

Lignin

0 20 40

0,0

0,5

1,0

Eucalyptus wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 40 80 120

0,0

0,4

0,8Cellulose

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 20 40 60 80 100 120

0,00

0,05

0,10

Pine bark

COOH

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40

0

1

2

3

4

Xylan

COOH

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,3

0,6

0,9

Fir wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

COOHNO

CH4

NO2

H2S

HS

C2H

2

SO2

SO

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

Lignin

0 20 40

0,0

0,5

1,0

Eucalyptus wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 40 80 120

0,0

0,4

0,8Cellulose

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 20 40 60 80 100 120

0,00

0,05

0,10

Pine bark

COOH

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40

0

1

2

3

4

Xylan

COOH

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,3

0,6

0,9

Fir wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

COOHNO

CH4

NO2

H2S

HS

C2H

2

SO2

SO

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

Lignin

0 20 40

0,0

0,5

1,0

Eucalyptus wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 40 80 120

0,0

0,4

0,8Cellulose

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 20 40 60 80 100 120

0,00

0,05

0,10

Pine bark

COOH

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40

0

1

2

3

4

Xylan

COOH

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,3

0,6

0,9

Fir wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

COOHNO

CH4

NO2

H2S

HS

C2H

2

SO2

SO

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

Lignin

0 20 40

0,0

0,5

1,0

Eucalyptus wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 40 80 120

0,0

0,4

0,8Cellulose

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 20 40 60 80 100 120

0,00

0,05

0,10

Pine bark

COOH

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40

0

1

2

3

4

Xylan

COOH

NO

CH4

NO2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,3

0,6

0,9

Fir wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

0 10 20 30 40 50 60

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

COOHNO

CH4

NO2

H2S

HS

C2H

2

SO2

SO

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

Lignin

0 20 40

0,0

0,5

1,0

Eucalyptus wood

COOH

NO

CH4

NO2

C2H

2

Time (min)

Inte

nsi

ty (

A/(

mb

ar

mg))

*10

-6

Secondary products:

o Light hydrocarbons (CH4 and C2H2), nitrogen oxides were detected in all samples. o Sulfur compounds (HS, H2S and SOx) were only present in the lignin mass spectra.

31


H2 and CO > CO2 Char steam gasification C+H2O ↔ CO + H2

CO2 > CO Fir wood Water-Gas- Shift: CO+H2O ↔ CO2 + H2 ↑ Ca

↑ CH4 Eucalyptus wood sample ↑ K Methanation: C+2H2 ↔ CH4

CH4 C2H2 NO SH H2S C2H5O NO2 SO SO2

0.00

0.02

0.04

0.06

Celulosa

Lignina

Xilano

Madera de Abeto

Madera de Eucalipto

Corteza de Pino

SO2

NO2

SOCOOHH2SHSC

2H

2NO

CH4

H2 CO CO2

0

1

2

3

4

CO2

COH2

Gas

yie

ld(A

min

/(m

bar

mg))

·10

3

Cellulose

Lignin

Xylan

Fir wood

Eucalyptus wood

Pine bark

Low CO2 Cellulose and pine bark Boudouard reaction C + CO2 ↔ 2CO



TGA analysis

Kinetic analysis

1) Evaluation of the pyrolysis and combustion processes by TGA-MS

Partial objectives

8

32

33

Conclusions

The gasification process was more influenced by the inorganic matter contained in the ashes than by the composition of biomass. Standard models VM, SCM and RPM did not reproduce the gasification process at high conversion values for high ash content biomass (fir wood, eucalyptus wood, xylan and lignin). The addition of an auto-catalytic term to the SCM improved the fitting of the model in the whole conversion range. A direct correlation of the activation order (proposed parameter) was found with Ca content of lignocellulosic biomass, pointing out that it was the metal which had the highest influence in the gasification process.

Acknowledgements

34

We gratefully acknowledge financial support from Ministry of Science and

Innovation of Spain (CENIT-VIDA project).

Funding:

Thank you very much for your attention

GASIFICATION OF BIOMASS

CHAR OBTAINED VIA PYROLYSIS

D. López-González, M. Fernández-López, J.L. Valverde and L. Sánchez-Silva1*

Department of Chemical Engineering. University of Castilla-La Mancha. Spain

16

Characteristic Parameters:

• Initial decomposition temperature (Tdo): temperature where the sample decomposition starts (dw/dT > 0.1 %/ºC).

• Peak temperature (Tp): temperature where the maximum

weight loss rate is reached. • (dw/dT)max: maximum weight loss rate. • Ignition Temperature (Ti): point at which the tangent line to

the maximum weight loss rate and the tangent line to the point which decomposition started cross.

• Burnout Temperature (Tb): temperature where the combustion

process is finished (no noticeable weight loss is detected dw/dT < 0.1 %/ºC)

TGA Analysis


9

Mineral content determination:

Proximate analysis:

Ultimate analysis:

Thermogravimetric analysis:

Mass spectrometric analysis:

Thermogravimetric analyzer TGA-DSC 1 (METTLER Toledo)

Mass spectrometer Thermostar-GSD 320/quadrupole mass analyzer (PFEIFFER VACUUM)

Inductively coupled plasma (ICP) (Liberty Sequential. Varian)

Standard Procedure Volatile matter (VM): UNE-EN 15148 Ash content (AC): UNE-EN 14775 Moisture content (MC): UNE-EN 14774 Fixed Carbon*dab = 100 – (VM+AC+MC)*dab

CHNS/O analyzer (LECO CHNS-932) O*dab= 100-(C+H+N+S)*dab

RE

AC

TIN

G A

ND

G

AS

AN

AL

YS

IS

UN

ITS

CH

AR

AC

CT

ER

IZA

TIO

N

16

TGA Analysis

Ultimate analysis (wt.%)daf

Char

C H N S O

*

Cellulose 91.28 0.44 0.07 - 8.25

Lignin 68.02 0.49 0.88 0.16 30.44

Xylan 82.32 0.55 0.58 - 16.57

Fir wood 79.68 0.63 1.22 - 18.51

Eucalyptus wood 69.69 0.61 0.90 - 28.91

Pine bark 84.58 0.46 0.35 - 14.76

Ash

C H N S O

*

Cellulose - - - - N/A

Lignin - - - - N/A

Xylan - - - - N/A

Fir wood - - - - N/A

Eucalyptus wood - - - - N/A

Pine bark - - - - N/A

16

TGA Analysis

Pyrolysis process:

Volatiles

∆T

o Condensable fraction

o Non-Condensable fraction

Pyrolytic oil

CO. CO2. H2. CH4

CxHyOz N S ; inorganic constituents

Biomass fuel

Devolatilization

Char Ash ∆T

Char Gasification

o Tar

Synthesis gas (H2 + CO)

16

TGA Analysis

0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.2

0.4

0.6

0.8

1.00.0

0.2

0.4

0.6

0.8

1.0

Fixed

Carb

on

Sugarcane bagasse

Grape

Maize

Olive

Rapeseed

Rice husk

Sawdust

Sunflower

Brown Kelp Giant

Water hyacinth

Fir wood

Tobacco

Pine bark

Cotton wastes

Eucalyptus wood

Straw

Ash

Volatile Matter

Terrestrial biomass:

Marine biomass:

Main components of Terrestrial biomass

Main properties o interest for biomass processing as an energy source:

•Fixed Carbon content (FC)

•Volatile matter (VM)

•Ash content (AC)

Fir Wood Eucalyptus Wood

Corn

o Fir Wood

o Eucalyptus Wood

o Pine bark

o Microalgae Nannochloropsis Gaditana (NG microalgae)

Criteria 1: AC VM Criteria 2: AC FC

Pine bark

9

12

Ultimate analysis:

Ultimate Analysis (%wt.)

Biomass sample C H N S Odiff

Cellulose 42.2 6.1 0.01 0.06 51.6

Lignin 62.1 5.9 0.51 0.54 31.0

Xylan 38.4 6.2 0.01 0.11 55.3

Eucalyptus wood 41.6 4.9 0.38 0.03 53.1

Fir wood 50.1 6.1 0.44 0.00 43.4

Pine bark 52.7 5.5 0.01 0.08 41.7

C content: Lignin > Pine > Fir > Eucalyptus > Cellulose > Xylan H content:

N content: below 1 wt.%; lignin had the highest content

S content: W > S > RP > BP > CR O content:


CHNS/O analyzer (LECO CHNS-932) O*dab= 100-(C+H+N+S)*dab

similar for all samples

Xylan > Eucalyptus > Cellulose > Fir > Pine > Lignin

Documents

GASIFICATION OF BIOMASS CHAR OBTAINED VIA PYROLYSIS