This document describes a method for determination of grindability of graded thermally treated and densified biomass fuels such as classified in ISO/TS 17225-8, for the purpose of preparing fuels with a defined particle size distribution for effective combustion in pulverized fuel boilers. The grindability characteristics determined by the test method provide guidance as to the pulverizing mill performance when utilizing such fuels.

Apart from pelletized materials as described in ISO/TS 17225-8, the method can also be applied to non-compressed or non-densified thermally treated biomass as specified in ISO 17225-1:2021, Table 14 and Table 15.

The results created with this method are not relevant for large wood chips, since limitations apply for large pulverizing coal mills, which are typically not used for grinding materials such as chips.

Le présent document comprend les parties suivantes:

a) une compilation des méthodes d'essai utilisant la méthode du point de croisement;

b) des recommandations sur l'applicabilité et l'utilisation des essais utilisant la méthode du point de croisement pour les granulés de biocombustibles solides;

c) des informations relatives à l'application des données d'essais utilisant la méthode du point de croisement pour le calcul des conditions critiques dans les lieux de stockages.

Les données relatives à la production spontanée de chaleur déterminées à l'aide du présent document sont uniquement associées à la qualité et à l'âge spécifiques de l'échantillon de matériau.

Les informations déduites à l'aide du présent document sont destinées à être utilisées dans le contrôle qualité et dans l'identification des dangers et l'évaluation des risques associés aux procédures fournies dans l'ISO 20024.

Les méthodes décrites peuvent être utilisées pour d'autres substances que les granulés de biocombustibles solides (par exemple: les plaquettes de bois).

The emission and depletion factor and emission and depletion rate for various gas species emitted from sample within a closed test container is determined by means of gas chromatography.

The emission and depletion factor and emission and depletion rate provide guidance for ventilation requirements to keep gas concentrations below Permissible Exposure Levels (PEL) in spaces where workers can be exposed to the enclosed atmosphere.

NOTE 1 The method also allows determination of the total ethyl ester content in FAEE, but precision for this has not been established.

This Technical Specification does not determine the linolenic nor the poly-unsaturated alkyl ester content. Alternative techniques, such as EN 14103^[1] and EN 15779^[2], respectively, are available for this.

NOTE 2 For the purposes of this Technical Specification, the term "% (m/m)" is used to represent the mass fraction, µ.

In most actual cases, biodiesel is based on fatty acid methyl esters (FAME). These have also been used during the precision study for this test method. There is no indication that the methodology does not apply to other ester types, but the precision has not been determined nor compared.

NOTE For the purposes of this Technical Specification, the term "% (m/m)" is used to represent the mass fraction, µ.

— 1.1 forest, plantation and other virgin wood;

— 1.2 by-products and residues from wood processing industry;

— 1.3.1 chemically untreated used wood;

— 1.4 blends and mixtures.

This document covers hog fuel, which is produced with blunt tools, and wood chips, which are produced with sharp tools.

NOTE 1 1.2.2 By-products and residues from wood processing industry, which can include chemically treated material (e.g. glued, painted, laminated) are not allowed include halogenated organic compounds or heavy metals at levels higher than those in typical virgin material values (see Annex B in ISO 17225-1) or higher than typical values of the country of origin.

NOTE 2 If class I4 includes chemically treated used wood (1.3.2), it can be only used in the installations permitted to use 1.3.2.

ISO/TS 16996:2015 is applicable for the following elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Mo, Cd, Sb, and Pb. Concentrations from approximately 0,000 1 % and above can be determined depending on the element, the calibration materials used and the instrument used.

The document consists of three parts, as follows:

— Part I: Method for direct determination of bridging behaviour, to make it available for research and development purposes (see Clause 4).

— Part II: Implementing the measurement principle, to assist in the construction of test apparatus and to illustrate the performance of a bridging test (see Clause 5).

— Part III: Experience and results from bridging tests, to provide typical results on bridging for a wide range of biofuels already tested (see Clause 6).

1) fine (up to about 10 mm nominal top size) and regularly-shaped particulate materials that can be sampled using a scoop or pipe, e.g. sawdust, olive stones and wood pellets;

2) coarse or irregularly-shaped particulate materials (up to 200 mm nominal top size) that can be sampled using a fork or shovel, e.g. wood chips, hog fuel and nut shells;

3) large pieces (above 200 mm nominal top size) which are picked manually (e.g. firewood and briquettes).

This document can also be used for other solid biofuels not listed above if the procedures described in this document are applicable. This document specifies methods to be used, for example, when a sample is to be tested for moisture content, ash content, calorific value, bulk density, mechanical durability, particle size distribution, ash melting behaviour and chemical composition.

Additionally, it describes a method for the reduction of sample size and defines requirements on handling and storage of samples.

NOTE 1 If higher precision of analytical results is needed or when in doubt if this document is applicable ISO 18135 can be used. Using the number of increments given in this document the resulting precision for analytical results can be estimated with the formulas given in ISO 18135.

NOTE 2 Pellets can generate CO and CO₂ off gasses by nature. If pellets are sampled, check for CO and CO₂ and O₂ levels prior and during the sample taking process in a confined space like a container, silo or shed and have another person standby at the entrance.