Comparison of Rapid Moisture Content Determination … · Newly developed gravimetric or electric methods may be suitable alternatives to provide a rapid ... Moisture content determination

P 16 B Md 009

49th International Symposium on Forestry Mechanization September 7th, 2016

Theresa Mendel • Andreas Überreiter • Daniel Kuptz • Hans Hartmann

Comparison of Rapid Moisture Content Determination Methods for Wood Chips

P 16 B Md 009 Slide 2

Correct and on-time moisture content (MC) determination is crucial at many points during wood chip production

The standardized method, i.e. oven drying according to ISO 18134, consumes both time and labor

Newly developed gravimetric or electric methods may be suitable alternatives to provide a rapid and accurate MC determination

Introduction & research question

Mendel 16 B Md 110

Aim: Determination and comparison of the accuracy of selected measuring instruments for rapid MC determination of wood chips


Research of currently available and suitable rapid determination methods

Establishing contacts with manufacturers (8/20 positive feedbacks)

Materials & methods

Mendel 16 B Md 111

Stationary instruments

Lances

Thermogravimetric methods

Electric methods

Infrared drying

Dielectric method

Oven dry method

TDR method

Conductivity method

Memmert 105°C (Reference method)

Sartorius: MA35 A&P Instruments: UX3081

Ahlborn: Almemo

Gann: HT85T

IMKO: HD2- Sono M1

Schaller: humimeter BL2

Greisinger: GMH3851

Doser: AD22-CMS22

Schaller: humimeter BMA


Materials & methods

Mendel • Überreiter 16 B Md 112

A&P Instruments: UX3081

Sartorius: MA35 Schaller: Humimeter BMA

Schaller: Humimeter BL2

IMKO: HD2 Ahlborn: Almemo Feuchtefühler

Doser: AD22-CMS22

Greisinger: GMH 3851

Gann: Hydro-mette HT 85 T

Stationary instruments:

Lances:


Wood chip types used for measurements:

Materials & methods


1 = Energy roundwood chips: spruce 2 = Energy roundwood chips: beech 3 = Forest residue chips: deciduous trees 4 = Short rotation coppice chips: poplar 5 = Forest residue chips: coniferous trees

1 2 3

4 5

1 2 5 4 3


Moisture contents

Number of measurements per measuring device:

5 moisture content levels x 5 wood chip types x n n = 3-5 for stationary instruments n = 10 for lances

= 75 - 250 measurements in total

Materials & methods

Mendel 16 B Md 114

Moisture content (w-%)

As received 35 25 15 10

M35 M25 M10

A1 A2 B Property classes (ISO 17225-4)


Materials & methods


Drying

Homogenization

Storage in airtight plastic bags

Determination of bulk density

Measurements with infrared

dryers

Measurements with lances

Measurements with BMA

Determination of particle size distribution

Moisture content determination with reference method


Infrared dryer

Results & discussion

Mendel 16 B Md 117

Measuring instrument

Mean deviation (± SD) [w-%]

MA35 -0.7 (± 2.1)

UX3081 -2.6 (± 1.7)

0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

MC

: HT8

5T

Reference moisture content

0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

MC

: HD

2


MC

: GM

H38

51


ERC-spruce ERC-beech FRC-conifer FRC-deciduous SRC-poplar reference

* error measurements were excluded

*

0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: U

X308

1

Referenzwassergehalt

Energierundholz Fichte Energierundholz Buche Waldrestholz Nadelholz Waldrestholz Laubholz KUP Pappel Sollwertgerade

0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: U

X308

1



0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: M

A35



Reference moisture content Reference moisture content

w-% w-%

w-% w-% M

oist

ure

cont

ent:

Moi

stur

e co

nten

t:


Dieelectric methods


Mendel 16 B Md 118



BMA -0.5 (± 4.0)

BL2 3.8 (± 4.7)

AD22-CMS 22 -0.7 (± 4.0)

Almemo 1.5 (± 4.2)

0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

MC

: HT8

5T


0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

MC

: HD

2


MC

: GM

H38

51




*

0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: U

X308

1



0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: BM

A



Reference moisture content 0 10 20 30 40 50 70m-%

0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: BL

2




0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: AD

22-C

MS2

2



Reference moisture content 0 10 20 30 40 50 70m-%

0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: Al

mem

o




w-% w-%

w-% w-%

w-% w-%

w-% w-%

Moi

stur

e co

nten

t:

Moi

stur

e co

nten

t: M

oist

ure

cont

ent:

Moi

stur

e co

nten

t:


Conductivity and TDR method


Mendel 16 B Md 119



GMH3851 0.7 (± 4.9)

HT85T 1.9 (± 3.7)

HD2 -1.6 (± 5.1)

0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%

MC

: HT8

5T


0 10 20 30 40 50 70w-%0

10

20

30

40

50

70

w-%M

C: H

D2


MC

: GM

H38

51




*

0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: U

X308

1



0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: G

MH

3851



w-%

0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: H

D2





0 10 20 30 40 50 70m-%0

10

20

30

40

50

70

m-%

Was

serg

ehal

t: H

T85T



Reference moisture content w-%

w-% w-%

w-%

w-%

Moi

stur

e co

nten

t:

Moi

stur

e co

nten

t: M

oist

ure

cont

ent:



Mendel 16 B Md 116


Measuring range [w-%]

n


Y intercept

Slope

r²

Infra

red Sartorius: MA35 0 – 100 67 -0.7 (± 2.1) -0.66 1.00 0.98

A&P Instruments: UX3081 0 – 100 68 -2.6 (± 1.7) -1,66 0.96 0.99

Die

lect

ric

Schaller: humimeter BMA 5 – 70 120 -0.5 (± 4.0) 3.65 0.85 0.95

Schaller: humimeter BL2 10 – 50 190 3.8 (± 4.7) -3.50 1.28 0.96

Doser: AD22-CMS 22 0 – 50 220 -0.7 (± 4.0) 1.00 0.93 0.90

Ahlborn: Almemo 0 – 50 220 1.5 (± 4.2) 2.88 0.94 0.90

Con

duct

ivity

Greisinger: GMH3851 5 – 50 190 0.7 (± 4.9) -3.53 1.21 0.88

Gann: HT85T 4 – 50 220 1.9 (± 3.7) -4.27 1.10 0.94

TDR

IMKO: HD2-Sono M1 0 – 50 206 -1.6 (± 5.1) 4.14 0.76 0.86


Comparison of measurements accuracy


Mendel 16 B Md 120

Refe

renc

e

MA3

5UX

3081

BMA

BL2

AD22

-CM

S22

Alm

emo

GM

H 38

51*

HT85

T

HD2 °C

-20

-15

-10

-5

0

5

10

15

25

w-%

Dev

iatio

n (a

bs.)

from

refe

renc

e va

lue

25~75% Min~Max Median Mean


Influence of different moisture contents on accuracy of measurements


Mendel 16 B Md 121

Refe

renc

eM

A35

UX30

81BM

ABL

2AD

22-C

MS2

2Al

mem

oG

MH

3851

*HT

85T

HD2 °C

Refe

renc

eM

A35

UX30

81BM

ABL

2AD

22-C

MS2

2Al

mem

oG

MH

3851

HT85

THD

2

-20

-15

-10

-5

0

5

10

15

25

w-%

Dev

iatio

n (a

bs.)

from

refe

renc

e va

lue

25~75% Min~Max Median Mean

> 25 w-%< 25 w-%


Influence of bulk density on accuracy of measurements


Mendel 16 B Md 122

ERC-spruc

e

ERC-beec

h

FRC-conif

erous

FRC-decid

uous

SRC-popla

r °C-20

-15

-10

-5

0

5

10

15

25

w-%

Bulk density (at moisture content: 15 w-%)

-320

-240

-160

-80

0

80

160

240

400

kg m-3

Dev

iatio

n (a

bs.)

from

refe

renc

e va

lue

Bul

k de

nsity


The high accuracy of the oven dry method could not be reached by any of the tested devices

by using a high amount of samples the average MC of all measurements approximated the reference value

With increasing MC the accuracy especially of electric methods decreased

Individualized calibration curves can increase accuracy

The MA35 scored best results despite of a small sample size and large measuring range

Nevertheless, the heterogeneity of wood chips should not be disregarded

Representative sampling and accurate sample preparation are thereby fundamental for obtaining high-quality results

Conclusion

Mendel 16 B Md 123

P 16 B Md 009

Thank you for your attention!

This study was funded by: Federal Ministry of Food and Agriculture Awarded by: Agency for Renewable Resources Contact: Theresa Mendel Technology and Support Centre (TFZ) Centre of Excellence for Renewable Resources Schulgasse 18, D-94315 Straubing phone: +49 (0) 9421 300-113 email: [email protected] www.tfz.bayern.de

Documents

Comparison of Rapid Moisture Content Determination … · Newly developed gravimetric or electric methods may be suitable alternatives to provide a rapid ... Moisture content determination