ISO 21644-2021 pdf free download – Solid recovered fuels — Methods for the determination of biomass content
5Principle
The determination of the biomass content is based on selective dissolution, manual sorting or 14Cmeasurement of biomass in solid recovered fuel.The choice for the method to be used is describedin Clause 6. The biomass content gives an estimation of the content of the biogenic fraction in solidrecovered fuel.
6 Determination of biomass content6.1Sampling
Sampling,transport, storage of the solid recovered fuel and sample preparation in the field shall beconducted according to Is0 21645 and lSO 21646.
6.2Sample preparation
Preparation of the test sample for the 14C or SDM shall be conducted according to lS0 21646.For theMsort, no sample preparation is performed.
Since SRF is considered as a heterogeneous material, the minimum sample amount to be used for eachtest shall be:
14C method: a quantity between 0,4 and 2 g of the material with a nominal top size of 1 mm orless, depending on the device used for combustion (bomb, combustion tube furnace or elementalanalyser) or the quantity indicated by the constructor in the case of the use of a laboratory scalecombustion apparatus;
selective dissolution method (SDM): at least5 g of the material with a nominal top size of 1 mm orless;manual sorting method (Msort): at least as big as the minimum sample size according to lS0 21645(as received), as calculated in lS0 21646.
6.3 Applicable methods
For the determination of biomass content three methods are available:
1) the instrumental 14C method shall be according to Annex A. This method is based on the
determination of the ratio of 1C to the total carbon content; the 1C is proportional to the biomasscontent of the SRF.This method is suitable for samples of all types of fuel and shall be according toAnnexA.A value of 10 % biogenic carbon can be considered as the lower range of application of i4Cmethod by liquid scintillation counter (LSC);
2) the selective dissolution method(SDM) shall be according to Annex B. The determination of the
biomass content by the SDM is based on the property of biomass that it can be dissolved in asulphuric acid / hydrogen peroxide mixture.This method has limitations that makes it less suitable if the content of natural and/or synthetic rubber in the SRF is more than 10 %, or if the sum of the content of hard coal, coke, brown coal, lignite, degradable plastics of fossil origin, non-degradable plastic of biogenic origin, oil or fat present as a constituent of biomass, wool, viscose, nylon, polyurethane or other polymers containing molecular amino groups and silicon rubber exceeds 5 %. Additional information about these limitations is found in Annex D. The selective dissolution method (SDM) is applicable for the biomass percentage content between 10 % and 90 %;
3) the manual sorting method (Msort) shall be according to Annex C. The determination of the biomass content by the manual sorting method is based on the visual examination of fractions and their separation on the basis of their nature and origin. The method is suitable for samples with a particle size >10 mm.
For the limitations of the three methods see Annex D.
7 Expression of results
Depending on the use of the results, three different dimensions are used to express the biomass content:
a) biomass in percent by mass w B ;
b) biomass in percent by calorific value w B,cal ;
c) biomass in percent by carbon content w B,TC .
The expression of results by 14 C method shall be according to Annex A.
The expression of results by SDS method shall be according to Annex B.
The expression of results by Msort method shall be according to Annex C.ISO 21644 pdf download.