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ISO/TS 20048-1 pdf free download

ISO/TS 20048-1-2020 pdf free download.Solid biofuels – Determination of off-gassing and oxygen depletion characteristics一 Part 1: Laboratory method for the determination of off-gassing and oxygen depletion using closed containers.
The effective gas volume (V) for a test container with a volume of 3 500 ml (V) loaded to 75 % with wood pellets and with a volume of void of 50% can be calculated as follows:
V= 0.25 x 3 500 [mlj+0,75 x 3 500 ImlI x 0.5 = 3 500 [mu x 0.625 = 2 188 ml
Guidance for selecting container size in relation to gas sample size required by the GC for a selected gas depletion volume is provided in Z3.
5.3 Gas sampler
A gas-tight GC syringe shall be used for drawing gas test samples through septum in the container sampling port nipple. It is recommended that the capacity of the syringe be at least 3 times the volume of the sampling tube and sampling loop of the GC or as recommended by the manufacturer of the GC (see The syringe shall have a scale with a resolution of 1 ml and a valve to secure the sample after drawing. It is best to use needles that have a hole on the side rather than the tip to prevent silicone or neoprene material blocking the hole while sampling.
The gas sample is injected directly from the sampler syringe into the GC sample port.
5.4 Ovens
The temperature within the test containers shall be controlled by placing the containers in ovens automatically controlling the temperature in the range of 20 °C to 50 °C ± 1 °C. A separate oven is required for each temperature selected for testing. The ovens shall be able to hold the size of containers required to achieve the necessary accuracy of the off-gassing determination.
Since temperature of biomass under test has a propensity to self-generate heatl4l at testing temperatures above 40 °C, particularly if the moisture In the material is high, a thermocouple should be placed inside the material in one of the containers. A thermocouple in the centre of the test volume will help monitoring the uniformity of the temperature.
5.5 Gas chromatograph (GC) analyser
The detection limit for each gas species and related concentrations is determined by the type of column in the GC. The manufacturer of the GC should be consulted. GC with thermal conductivity detector (TCD) shall be used to detect and quantify permanent gases and light hydrocarbons. Packed and capillary columns could be used with TCD to measure permanent gases. A combination of TCD and FID (flame ionization detector) could also be used for gas measurements depending on the GC configuration.
NOTE 1 Helium (He) Is usually used as carrier gas but, e.g., nitrogen or argon are other possible alternatives.
NOTE 2 PEL for CO Is in the range of 25 ppmv to 100 ppmv depending on jurisdiction and on the duration of the exposure. Gas chromatography allows identification of a large number of non-condensable like CO. CO2. CH4 N2. H2, and °2 The PEL for those compounds can be found in occupational hygiene databases. The occupational health lower limit for oxygen Is 19,5 %.
Annex A provides a generic orientation of operation and calibration of a GC.
6 Biomass sampling and sample preparation
6.1 General
Sampling and sample preparation of biomass shall be done in accordance with ISO 18135 and ISO 14780 respectively.
6.2 Test sample characterization
The test sample characterization shall be done in accordance with the following international standards;
a) Moisture ISO 18134-1 or ISO 18134-2
b) Particle size distribution ISO 17827-2
c) Fines content ISO 18846
d) Bulk density ISO 17828
e) Particle density ISO 18847
If available, note the origin, species and age of the test sample in the test report (Clause 9).
6.3 Test sample size
The total sample size depends on the test container configuration selected (7.3). At least three test sample fractions shall be prepared; one for test sample characterization (.2) and the others for off- gassing/oxygen depletion tests.
EXAMPLE Volume of material required per temperature test is V x 4 plus required volume for characterization depending on the selected test under 62. Material for each additional test temperature requires V x 4.
7 Procedure
7.1 Determination of porosity in biomass test sample
The characteristics of the biomass test sample can vary depending on shape and size of the material as well as amount of entrained dust.ISO/TS 20048-1 pdf download.

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