Biomechanical pulping of Eucalyptus

wood chips

André Ferraz1, Anderson Guerra2, Régis Mendonça2 and Paulo Pavan2

1. Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, SP, Brasil 2. Centro de Biotecnologia, Universidad de Concepción, Concepción, Chile 3. Melhoramentos Papéis, Caieiras, SP, Brasil

Biopulping is defined as the fungal

pretreatment of wood chips for

production of mechanical or chemical

pulps

Introduction

0

100

200

300

400

500

600

0 500 1000 1500 2000 2500

Cumulative energy (wt.h/kg)

Pu

lp F

ree

ne

ss

(m

L)

Introduction

Biomechanical pulping of loblolly pine

Energy versus freeness

Energy saving at Freeness of 100 mL = 38%

control

biotreated

Properties Control Biotreated *

Freeness (mL) 113 100

Burst Index (kN/g) 0.59 1.16

Tear Index (mNm2/g) 2.85 5.15

Tensile index (Nm/g) 15.6 24.6

Brightness (% ISO) 51.4 39.1

Typical strength and optical properties of

unbleached loblolly pine-TMP pulps

Introduction

Biomechanical pulping of Eucalyptus: Energy

requirements and savings – lab-scale TMP

Control Biotreated * Refining Energy

(kwt.h/ton)

Freeness (mL) Energy

(kwt.h/ton)

Freeness

(mL)

TMP 351 - 315 -

RMP 654 402 518 390

TOTAL 1005 402 833 390

Energy savings (% over control) 17

Introduction

1157 526 Breaking length (m)

11.35 5.16 Tensile index (Nm/g)

2.93 1.03 Tear (mNm2/g)

0.34 0.20 Burst (kN/g)

Biotreated Control Parameters

Typical strength and optical properties of unbleached

Eucalyptus grandis-TMP pulps (Freeness = 400 mL )

Introduction

Brightness 60% ISO 44% ISO

Wood biodegradation

White-, brown-, and soft-

rot fungi

For biopulping, minimal

degradation of cellulose is

required

Two types of white-rot:

erosive and non-erosive

Wood biodegradation

Erosive degradation of wood cell wall

Non-erosive degradation of wood cell wall

Trametes versicolor , non-selective white-rot

60

70

80

90

100

708090100

Wood weight (% of the initial)

Wo

od

co

mp

on

en

t

(% o

f th

e in

itia

l)

glucan

polyoses

lignin

Ceriporiopsis subvermispora , selective white-rot

60

70

80

90

100

859095100

Wood weight (% of the initial)

Wo

od

co

mp

on

en

t

(% o

f th

e in

itia

l)

glucan

polyoses

lignin

Mass-balance of wood components during

Eucalyptus globulus biotreatment

Wood biodegradation

Lab-scale

Large-scale

Main focus

Preparation of TMP pulps on a mill-scale by processing wood chips biotreated with C. subvermispora in a 50-ton chip pile Evaluation of bleachability and brightness stability of bio-TMP pulps

Mechanical pulping of Eucalyptus grandis

biotreated on a 50-ton pilot plant

Subject of this work

Eucalyptus grandis wood chips were treated in a biopulping

pilot-plant by Ceriporiopsis subvermispora

Materials and methods

Colonized wood chips were used as start-up inoculum seed for the

scaled-up biodegradation experiments (30 days culturing).

Materials and methods

1st scale-up on pilot-plant: 40kg of lab-inoculum seed + 760 kg of

decontaminated wood chips (5% w/w). (60 days culturing)

2nd scale-up on pilot-plant: 800 kg of pilot-inoculum seed + 7.2 ton of

decontaminated wood chips (10 % w/w). (90 days culturing)

Final scale-up on pilot-plant: 8-ton pile pre-cultured wood chips used to build

a 45-ton pile (18 % w/w). (60 days culturing)

Inoculation on a pilot plant

Build-up of the chip pile

Biotreated wood chips were refined on a mill

scale to produce TMP pulps

2-stage refining: 1st stage = TMP

2nd stage = RMP

Pulps were bleached with H2O2 after a Q-stage

Bleached pulps were submitted to photo- or

thermal-reversion to evaluate brightness stability

Materials and methods

Results and Discussion Energy consumption during TMP and CTMP refining of biotreated E. grandis (450 mL Freeness)

1st stage

2nd stage

total energy

913 Average Energy (kWh/ton) 745 756 1038

Energy saving (%) 18 27

Brightness Control TMP: 60% ISO Bio-TMP: 44% ISO

Bleaching of E. grandis-TMP pulps

H2O2 charge

(% on dry basis)

Consistency

(% on dry basis)

Temperature

(ºC)

Time

(h)

0 5 40 0.5

4 10 60 3

Process variables evaluated (24 experimental design)

Only H2O2 charge affected final brightness of

the pulps within 95% confidence level

Bleaching of E. grandis-TMP pulps

Effect of H2O2 charge

40

50

60

70

80

-2 0 2 4 6 8 10 12 14

H2O2 chrage (% on pulp)

Bri

gh

tne

ss

(%

IS

O) control TMP

BioTMP

only Q-stage

40

45

50

55

60

65

0 50 100 150 200

Treatment time (h)

Bri

gh

tne

ss

(%

ISO

)

BioTMP

controlTMP

Thermo-reversion

20

30

40

50

60

70

0 2 4 6 8

Treatment time (h)

Bri

gh

tne

ss

(%

ISO

)

Photo-reversion

BioTMP

control TMP

Brightness reversion in

TMP-pulps from E. grandis

30

35

40

45

50

55

60

40 50 60 70 80

Initial brightness (%ISO)

Bri

gh

tnes

s l

ost

(%

IS

O)

aft

er 4

ho

urs

of

ph

oto

-rev

ers

ion

A

Bio-TMP TMP

B

0

5

10

15

20

25

30

30 40 50 60 70 80

Initial brightness (%ISO)

Bri

gh

tnes

s l

ost

(% I

SO

)

aft

er 1

44h

of

therm

al-

rever

sio

n

Bio-TMP

TMP

Brightness reversion in

TMP-pulps from E. grandis

Conclusion Biomechanical pulping of E. grandis on a pilot scale

promotes 18% of energy savings for preparing pulps of

450 mL of Freeness

Bio-TMP pulps from E. grandis are significantly darker

than control-TMP pulps

Brightness of bio-TMP pulps increases 10 points after a

simple alkaline washing

Brightness reversion in biopulps and control pulps was

similar

Research supported by FAPESP,

CNPq, CAPES, SCTDE/SP and

Melhoramentos Ltd.

Thanks to Dr M. Akhtar (Biopulping

International INC) and Dr R. Swaney

(Univ. of Wisconsin) for helpful

discussions on the building and start-

up of the biopulping pilot plant.

Acknowledgments