Comparison of Rapid Moisture Content Determination Methods for Wood Chips

Transcription

1 Comparison of Rapid Moisture Content Determination Methods for Wood Chips 49th International Symposium on Forestry Mechanization September 7th, 216 Theresa Andreas Überreiter Daniel Kuptz Hans Hartmann P 16 B Md 9

2 Introduction & research question 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 Aim: Determination and comparison of the accuracy of selected measuring instruments for rapid MC determination of wood chips P 16 B Md 9 16 B Md 1 Slide 2

3 Materials & methods Research of currently available and suitable rapid determination methods Establishing contacts with manufacturers (8/2 positive feedbacks) Thermogravimetric methods Oven dry method Infrared drying Memmert 5 C (Reference method) Sartorius: MA35 A&P Instruments: UX381 Stationary instruments Dielectric method Schaller: humimeter BMA Schaller: humimeter BL2 Doser: AD22-CMS22 Ahlborn: Almemo Electric methods Conductivity method Greisinger: GMH3851 Gann: HT85T Lances TDR method IMKO: HD2- Sono M1 P 16 B Md 9 16 B Md 111 Slide 3

4 Materials & methods Stationary instruments: A&P Instruments: UX381 Sartorius: MA35 Schaller: Humimeter BMA Lances: Schaller: Humimeter BL2 Doser: AD22-CMS22 Ahlborn: Almemo Feuchtefühler Greisinger: GMH 3851 Gann: Hydromette HT 85 T IMKO: HD2 Überreiter P 16 B Md 9 16 B Md 112 Slide 4

5 Materials & methods Wood chip types used for measurements: = Energy roundwood chips: spruce 2 = Energy roundwood chips: beech = Forest residue chips: deciduous trees 4 = Short rotation coppice chips: poplar 5 = Forest residue chips: coniferous trees Überreiter P 16 B Md 9 16 B Md 113 Slide 5

6 Materials & methods Moisture contents As received Moisture content (w-%) M35 M25 M B A2 A1 Property classes (ISO ) Number of measurements per measuring device: 5 moisture content levels x 5 wood chip types x n n = 3-5 for stationary instruments n = for lances = measurements in total P 16 B Md 9 16 B Md 114 Slide 6

7 Materials & methods Determination of bulk density Homogenization Storage in airtight plastic bags Drying Measurements with infrared dryers Measurements with lances Measurements with BMA Determination of particle size distribution Moisture content determination with reference method Überreiter P 16 B Md 9 16 B Md 115 Slide 7

8 Results & discussion Infrared dryer 7 m-% w-% Moisture Wassergehalt: content: MA Wassergehalt: UX381 7 m-% w-% m-% 7 Reference Referenzwassergehalt moisture content Moisture Wassergehalt: content: UX MC: GM MC: HD2 3 2 MC: H w-% Energierundholz Fichte Energierundholz Buche w-% m-% w-% Waldrestholz Nadelholz Waldrestholz Laubholz 5 KUP Pappel 5 Sollwertgerade w-% m-% w-% 7 Reference Referenzwassergehalt moisture content w-% 7 Energierundholz ERC-spruce Fichte Energierundholz ERC-beech Buche Waldrestholz FRC-conifer Nadelholz Waldrestholz FRC-deciduous Laubholz KUP SRC-poplar Pappel Sollwertgerade reference Energierundholz Fichte Energierundholz Buche Waldrestholz Nadelholz Waldrestholz Laubholz KUP Pappel Sollwertgerade * error measurements were excluded Measuring instrument Mean deviation (± SD) [w-%] MA (± 2.1) UX (± 1.7) m-% 7 Referenzwassergehalt P 16 B Md 9 16 B Md 117 Slide 8

9 MC: H 3 2 Results & discussion -% ntent -% 7 ntent -% w-% Dieelectric methods 7 P 16 B Md 9 16 B Md 118 Measuring instrument Energierundholz ERC-spruce Fichte Energierundholz ERC-beech Buche Waldrestholz FRC-conifer Nadelholz Waldrestholz FRC-deciduous Laubholz KUP SRC-poplar Pappel Sollwertgerade reference * error measurements were excluded Slide 9 Mean deviation (± SD) [w-%] BMA -.5 (± 4.) BL2 3.8 (± 4.7) AD22-CMS (± 4.) Almemo 1.5 (± 4.2) Moisture Wassergehalt: content: BMA Moisture Wassergehalt: content: AD22-CMS22 7 w-% m-% w-% m-% 7 Reference Referenzwassergehalt moisture content 7 m-% w-% w-% m-% 7 Reference Referenzwassergehalt moisture content 7 Energierundholz Fichte Energierundholz Buche Waldrestholz m-% w-% Nadelholz Waldrestholz Laubholz KUP Pappel Sollwertgerade 5 Moisture Wassergehalt: content: BL w-% m-% 7 Reference Referenzwassergehalt moisture content 7 Energierundholz Fichte Energierundholz Buche Waldrestholz m-% Nadelholz w-% Waldrestholz Laubholz KUP Pappel Sollwertgerade 5 Moisture Wassergehalt: content: Almemo w-% m-% 7 Reference Referenzwassergehalt moisture content E E W W K S E E W W K S

10 Results & discussion Conductivity and TDR method P 16 B Md 9 16 B Md 119 Measuring instrument Slide Mean deviation (± SD) [w-%] GMH (± 4.9) HT85T 1.9 (± 3.7) 7 HD2-1.6 (± 5.1) m-% Wassergehalt: UX Moisture Wassergehalt: content: HT85T Moisture Wassergehalt: content: GMH m-% w-% m-% w-% MC: GMH3851 MC: HD2 7 w-% w-% m-% 7 Referenzwassergehalt w-% 7 7 w-% w-% MC: HT85T m-% w-% 5 w-% 7 Referenzwassergehalt * Moisture Wassergehalt: content: HD2 7 Energierundholz Fichte Energierundholz Buche m-% w-% Waldrestholz Nadelholz Waldrestholz Laubholz KUP Pappel 5Sollwertgerade w-% m-% 7 Referenzwassergehalt w-% 7 Energierundholz Fichte Energierundholz Buche Waldrestholz Nadelholz Waldrestholz Laubholz KUP Pappel Sollwertgerade Energierundholz ERC-spruce Fichte Energierundholz ERC-beech Buche Waldrestholz FRC-conifer Nadelholz Waldrestholz FRC-deciduous Laubholz KUP SRC-poplar Pappel Sollwertgerade reference * error measurements were excluded Ene Ene Wa Wa KU Sol

11 Results & discussion Measuring instrument Measuring range [w-%] n Mean deviation (± SD) [w-%] Y intercept Slope r² Infrared Sartorius: MA (± 2.1) A&P Instruments: UX (± 1.7) -1, Schaller: humimeter BMA (± 4.) Dielectric Schaller: humimeter BL (± 4.7) Doser: AD22-CMS (± 4.) Ahlborn: Almemo (± 4.2) Conductivity TDR Greisinger: GMH (± 4.9) Gann: HT85T (± 3.7) IMKO: HD2-Sono M (± 5.1) P 16 B Md 9 16 B Md 116 Slide 11

12 Results & discussion Comparison of measurements accuracy Deviation (abs.) from reference value 25 w-% Reference 25~75% Min~Max Median Mean MA35 UX381 BMA BL2 AD22-CMS22 Almemo GMH 3851* HT85T HD2 P 16 B Md 9 16 B Md 12 Slide 12

13 Results & discussion Influence of different moisture contents on accuracy of measurements Deviation (abs.) from reference value 25 w-% Reference MA35 25~75% Min~Max Median Mean UX381 BMA BL2 Almemo GMH 3851 HT85T HD2 AD22-CMS22 < 25 w-% > 25 w-% Reference MA35 UX381 BMA BL2 Almemo GMH 3851* HT85T HD2 AD22-CMS22 C P 16 B Md 9 16 B Md 121 Slide 13

14 Results & discussion Influence of bulk density on accuracy of measurements Deviation (abs.) from reference value 25 w-% ERC-spruce Bulk density (at moisture content: 15 w-%) ERC-beech FRC-coniferous FRC-deciduous SRC-poplar 4 kg m Bulk density P 16 B Md 9 16 B Md 122 Slide 14

15 Conclusion 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 P 16 B Md 9 16 B Md 123 Slide 15

16 Thank you for your attention! This study was funded by: Federal Ministry of Food and Agriculture Awarded by: Agency for Renewable Resources Contact: Theresa Technology and Support Centre (TFZ) Centre of Excellence for Renewable Resources Schulgasse 18, D Straubing phone: +49 () P 16 B Md 9