EN 15443:2011

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Trdna alternativna goriva - Metode za pripravo laboratorijskega vzorcaFeste Sekundärbrennstoffe - Verfahren zur Herstellung von LaboratoriumsprobenCombustibles solides de récupération - Méthodes de préparation des échantillons de laboratoireSolid recovered fuels - Methods for the preparation of the laboratory sample75.160.10Trda gorivaSolid fuelsICS:Ta slovenski standard je istoveten z:EN 15443:2011SIST EN 15443:2011en,de01-maj-2011SIST EN 15443:2011SLOVENSKI
STANDARDSIST-TS CEN/TS 15443:20071DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15443
March 2011 ICS 75.160.10 Supersedes CEN/TS 15443:2006English Version
Solid recovered fuels - Methods for the preparation of the laboratory sample
Combustibles solides de récupération - Méthodes de préparation des échantillons de laboratoire
Feste Sekundärbrennstoffe - Verfahren zur Herstellung von Laboratoriumsproben This European Standard was approved by CEN on 22 January 2011.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
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Determination of the changing shape factor . 26A.1 Introduction . 26A.2 Procedure . 26Annex B (normative)
Determination of the shape factor . 28B.1 Introduction . 28B.2 Procedure . 28Annex C (informative)
Examples of sample preparation. 29C.1 Introduction . 29SIST EN 15443:2011

Data on the precision of sample preparation . 34D.1 Introduction . 34D.2 Scope . 34D.3 Trueness . 34D.4 Repeatability and reproducibility . 34D.5 Robustness . 35D.5.1 General . 35D.5.2 Type of solid recovered fuel . 35D.5.3 Level of particle size reduction . 35Bibliography . 37 SIST EN 15443:2011

EN 15002 is available [2]. SIST EN 15443:2011

Figure 1 — Links between the essential elements of a testing program
1) To be published. SIST EN 15443:2011

When the laboratory sample is further prepared (reduced) by subdividing, mixing, grinding, or by combinations of these operations, the result is the test sample. When no preparation of the laboratory sample is required, the laboratory sample is the test sample. A test portion is removed from the test sample for the performance of the test or for analysis. NOTE 2
The laboratory sample is the final sample from the point of view of sample collection but it is the initial sample from the point of view of the laboratory. NOTE 3
Several laboratory samples may be prepared and sent to different laboratories or to the same laboratory for different purposes. When sent to the same laboratory, the set is generally considered as a single laboratory sample and is documented as a single sample. 3.5 lot defined quantity of fuel for which the quality is to be determined 3.6 moisture analysis sample sample taken specifically for the purpose of determining total moisture 3.7 nominal top size d95 aperture size of the sieve used in EN 15415-1 through which at least 95 % by mass of the material passes 3.8 particle size reduction reduction of the nominal top size of a sample or sub-sample 3.9 sample quantity of fuel, representative of a larger mass for which the quality is to be determined 3.10 sample division reduction of the mass of a sample or sub-sample 3.11 sub-sample portion of a sample 3.12 test portion sub-sample of a laboratory sample consisting of the quantity of material required for a single execution of a test method 4 Symbols and abbreviations For the purposes of this document, the following symbols and abbreviated terms apply. α is a constant in third power law d95 is the nominal top size in mm m is the mass of a sample in gram SIST EN 15443:2011

is the shape factor 5 Principles of correct sample preparation The main purpose of sample preparation is that a sample is reduced to one or more test portions that are in general smaller than the original sample. The main principle for sample preparation is that the composition of the sample as taken on site shall not be changed during each step of the sample preparation and that possible requirements of the analysis methods to be performed are obeyed. Each sub-sample shall be representative for the original sample. To reach this goal every particle in the sample before sample preparation shall have an equal probability of being included in the sub-sample retained after sample preparation. Also the loss of moisture and other volatile components shall be minimised if these components are analysed or influence the properties to be analysed. Two basic methods are used during the sample preparation. These methods are:  sample division;  particle size reduction of the sample. For granular materials generally the principle of the third-power law is accepted and shall be respected at each sample division step. The equation for this third power law is shown in Equation (1): 395
d.m×> (1) where m
is the mass retained after each sample division step in g; d95 is the nominal top size in mm; α is a constant over the whole sample preparation procedure for a particular material in g/mm3. The value and unit of constant α is fixed by the nominal particle size, d95, and the sample size, m, of the sample before sample preparation. EXAMPLE A sample of 10 kg of SRF fluff has d95 of 50 mm. For the analysis is a test portion of 5 g required. The third power law results in α = 10 000 g divided by 50 mm to the third power. The value of α is now 0,08 g/mm3. Using this value in Equation (1) for a reduced sample size results in a nominal top size for the particles in the test portion of 3,97 mm (cube root of 5,0 g divided by 0,08 g/mm3). Below in the table are shown the figures. m in g αααα In g/mm3
d95 in mm 10 000 0,08 50 5 0,08 3,97
Table 1 shows the resulting reduction factors for the minimum (sub-)sample size, if a certain reduction of the nominal top size is chosen and the third-power law is respected. The reduction factor of the nominal top size can be calculated by dividing the current nominal top size by the proposed nominal top size after size reduction. SIST EN 15443:2011

(sub-)sample size can be calculated by dividing the current minimum (sub-)sample size by the proposed minimum (sub-)sample top size after size reduction. Equation (1) can be used to calculate the exact values for each specific situation. Table 1 — Common values for desired reduction factor minimum
(sub-)sample size
Table 2 — Common values for desired reduction factor nominal top size
Chosen reduction factor of the nominal top size Resulting reduction factor for the minimum (sub-)sample size
Desired reduction factor for the minimum
(sub-)sample size Necessary reduction factor of the nominal top size 1,5 3,4
2 1,3 2 8
3 1,4 3 27
4 1,6 4 64
5 1,7 5 125
10 2,2 6 216
20 2,7 7 343
50 3,7 8 512
80 4,3 9 729
100 4,6 10 1 000
200 5,8 20 8 000
500 7,9 30 27 000
1 000 10,0
For SRF, however, many materials turn out to be far from granular. For example in fluff the particles turn out to be predominantly flat. Therefore, for solid recovered fuels, a correction can made for non-granular materials. Care is needed to avoid loss of fine particles and volatile components such as moisture and mercury during milling and other operations. If a sub-sample is required for the determination of moisture content, then the sample preparation shall be carried out by a procedure that does not conflict with the requirements of CEN/TS 15414-1, CEN/TS 15414-2 or EN 15414-3. It is recommended that, if moisture content of the material (as sampled) is to be determined, a separate moisture analysis sample is taken (as there is a risk of reducing the moisture content by sample preparation operations). If a sub-sample is required for the determination of mercury content, then the sample preparation shall be carried out by a procedure that does not conflict with the requirements of EN 15297. It is recommended that, if mercury content of the material (as sampled) is to be determined, a separate mercury analysis sample is taken (as there is a risk of reducing the mercury content by sample preparation operations). For materials that have to be examined for moisture and mercury content, care shall be taken for any significant heat build-up and risk of loss of moisture and mercury. SIST EN 15443:2011

Key 1 slot, width is at least 3 times the nominal top size of the material Figure 2 — Example of a riffle box 6.1.2 Rotary sample dividers A rotary sample divider shall have a feeder device adjusted so that the divider rotates at least 20 times while the sample is being divided. See Figure 3 for an example of a rotating divider. The manufacturer’s instruction manual shall always be followed. The inner dimensions of the equipment where the sample is feed shall be at least 3 times as wide as the nominal top size of the material to be processed. SIST EN 15443:2011

Key 1 feeder 2 funnel 3 rotating receiver 4 divided sample Figure 3 — Example of a rotary sample divider 6.1.3 Shovels and scoops A shovel or scoop used for manual sample division shall have a flat bottom, edges raised high enough to prevent particles rolling off, and shall be at least 3 times as wide as the nominal top size of the material to be processed. See Figures 4 and 5 for examples of a scoop and a shovel respectively.
Key d is the nominal top size Figure 4 — Example of a scoop SIST EN 15443:2011

Key l
is the length of the shovel A - A sectional view Figure 5 — Example of a shovel 6.2 Apparatus for particle size reduction 6.2.1 Coarse cutting mill or wood crusher Coarse cutting mills are used for cutting materials into lengths of about 10 mm to 30 mm (depending on the solid recovered fuel and the analyses to be performed). The equipment shall have a minimum of drying effect either by heating the materials or blowing air through them. The equipment shall be designed so that it does not lose dust or contaminate the material with pieces of metal, and shall be easy to clean. A cutting mill with no screens may be suitable for small quantities. 6.2.2 Cutting mill Cutting mills are used for particle size reduction of materials used as solid recovered fuels from about 10 mm to 30 mm down to about 1 mm or less (depending on the solid recovered fuel and the analyses to be performed). The mill shall be provided with screens of various aperture sizes covering this range, including an appropriate sieve to control the nominal top size of the material produced. Other apparatus may be used provided that they are designed so that they do not get blocked with the material that is being processed. Avoid the use of cutting mills whose cutting faces contain significant quantities of an element that is to be determined in the analysis. NOTE Cross beater mills can be used without any excessive dusting, when fitted with dust filters (like a filter sock) between the mill and the receiving container. They are suitable for final grinding of hard, wood type materials after the
pre-grinding with cutting type mills. 6.2.3 Shredder A shredder is an apparatus with a rotor equipped with hammers that shred the material which is fed to the shredder. Shredders are used for reducing the particle size down to 30 mm. In case of hardy and strong materials it can be necessary to perform the particle size reduction in more than one step. The use of SIST EN 15443:2011

Figure 6 — General sample preparation procedure 7.2 Step 1: Collection of the relevant information of the material to be sampled In the first step of sample preparation information shall be collected about the material to be sampled: a) the minimum sample size out of the sampling plan; b) the actual size of the sample, m0; c) the nominal top size of the sample; d) the shape factor of the sample; SIST EN 15443:2011

Description Method of reduction Used technique and apparatus Mass before reduction Mass after reduction Nominal top size before reduction Nominal top size after reduction Shape factor before reduction Shape factor after reduction Mass to be withheld for analysis Purpose of product of this reduction step Step 1 sample division of the combined sample in a sub-sample for further sample preparation and a sub-sample of untreated material sample division
determination of bulk density, durability of pellets, particle size distribution etc. Step 2
particle size reduction in order to make further sample division possible particle size reduction to < 30 mm
30 mm
Step 3
sample division in order to reduce the remaining mass or obtain sub-samples as general analyses sample sample division
30 mm 30 mm
sub-samples for moisture content, etc. Step 4
particle size reduction the remaining sub-sample in a sub-sample for further sample preparation sub-samples as general analyses sample particle size reduction to <1,0 mm
30 mm 1,0 mm
1,0
Step 5 sample division of the remaining sample material into the required general analysis sample(s) sample division
1,0 mm 1,0 mm 1,0 1,0
sub-samples for determination of ash, calorific value, chemical analysis etc. Step 6 particle size reduction in order to make further sample division possible particle size reduction to <0,25 mm
1,0 mm 0,25 mm 1,0 1,0
Step 7 sample division of the remaining sample material into the required test portions sample division
0,25 mm 0,25 mm 1,0 1,0
sub-samples for analysis where < 0,25 mm is required NOTE
Mass can only be withheld during a sample division step and not during a size reduction step. SIST EN 15443:2011

is the sample size of sample before particle size reduction; m2
is the sample size of sample after particle size reduction; f1
is the shape factor of sample before particle size reduction; f2
is the shape factor of sample after particle reduction; d1
is the nominal top size of sample before particle size reduction; d2
is the nominal top size of sample after particle size reduction. For more or less granular materials the shape factors f1 and f2 will be close to 1. In this case it is easier and cheaper to assume these two shape factors to be 1. For materials which are far from granular the shape factor f1 needs to be determined. The determination of the shape factor shall be as specified in EN 15442. The shape factor will change during the particle size reduction. Therefore the shape factor will approach 1,00 during particle size reduction. In Annex A is specified how a prognosis shall be made for the increase of the shape factor after particle size reduction. For each particle size reduction step a new shape factor and nominal top size shall be determined in order to establish whether the proposed sample preparation step complies with Equation (2). The shape factor can always be assumed to be 1,00. This will require additional particle size reduction, but will simplify the procedure and not influence the representativeness. 7.4 Step 3: Performing the sample preparation plan In the third step the sample preparation shall be performed as specified in the sample preparation plan. During the procedures of the actual sample preparation the following procedures shall be performed at any times: — homogenize the sub-sample material at every step thoroughly; — make sure no material of the sub-sample gets lost; — if possible do not leave out any components. When it is necessary to remove hard substances like metal (steel) to avoid damage to the mill this is allowed but shall be reported. The report shall include the weight percentage and type of substance which has been removed from the sample; — at all times enough sample material shall be withheld in order to perform all analyses. SIST EN 15443:2011

Key 1 discard Figure 7 — Quartering2)
Key 1 increment 2 sampling frame (> 3 d95) 3 end plates Figure 8 — Strip mixing
2) Source: Journal of chemometrics 2002;16 321-328 R. W. Gerlach, D. E. Dobb, G. Q. Raab and J. M. Nocerino SIST EN 15443:2011

a) spread the crushed sample into a rectangle with a maximum thickness three times the nominal top size b) arrange into 20 equal parts, e.g. into five equal parts length-wise and four equal parts breadth-wise
Key 1 bump plate c) take a scoopful of samples at random from each of the 20 parts by inserting the scoop to the bottom of the sample layer. Combine the 20 scoopfuls into a divided sample d) detail of taking an increment in one of the 20 parts by using the bump plate shown in c) Figure 9 — Manual increment division
f) Coning-and-quartering. This may be used for materials such as pellets, chips and fluff that can be worked with a shovel. It is suitable for producing sub-samples of these materials down to approximately
1 kg. Place the whole combined sample on a clean, hard surface. Shovel the sample into a conical pile, placing each shovelful on top of the preceding one in such a way that the solid recovered fuel runs down all sides of the cone and is evenly distributed and different particle sizes become well mixed. Repeat this process three times, forming a new conical pile each time. Flatten the third cone by inserting the shovel repeatedly and vertically into the peak of the cone to form a flat heap that has a uniform thickness and diameter and is no higher than the blade of the shovel. Quarter the flat heap along two diagonals at right angles by inserting the shovel vertically into the heap. See Figure 7 (A sheet-metal cross may be used for this operation if available.) Discard one pair of opposite quarters. Repeat the coning and quartering process until a sub-sample of the required size is obtained. NOTE This method is only used in case the other methods (a) to e)) are not applicable. 9 Methods for reducing laboratory samples to sub-samples and general analysis samples 9.1 General This clause describes the sample preparation performance. SIST EN 15443:2011
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