1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 14780:2011Solid biofuels SamplepreparationBS EN 14780:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 14780:2011. Itsupersedes DD
2、 CEN/TS 14780:2005 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PTI/17, Solid biofuels.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprov
3、isions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 69716 6ICS 75.160.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on
4、30 June 2011.Amendments issued since publicationDate Text affectedBS EN 14780:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14780 June 2011 ICS 75.160.10 Supersedes CEN/TS 14780:2005English Version Solid biofuels - Sample preparation Biocombustibles solides - Prparation des chantillons Fe
5、ste Biobrennstoffe - Probenherstellung This European Standard was approved by CEN on 5 May 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-
6、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. This European Standard exists in three official versions (English, French, German). A version in any other language made by translati
7、on under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, F
8、rance, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE
9、 FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14780:2011: EBS EN 14780:2011EN 14780:2011 (E) 2 Contents Foreword 3Introduction .41 Scope 52 Normative reference
10、s 53 Terms and definitions .54 Symbols and abbreviations 65 Principles of correct sample reduction .66 Apparatus .77 Sample reduction general principles . 108 Methods for sample division . 129 Method for reducing laboratory samples to sub-samples and general analysis samples . 1510 Storage and label
11、ling . 1711 Performance characteristics . 17Annex A (informative) Precision in relation to division method 18Bibliography . 24BS EN 14780:2011EN 14780:2011 (E) 3 Foreword This document (EN 14780:2011) has been prepared by Technical Committee CEN/TC 335 “Solid biofuels”, the secretariat of which is h
12、eld by SIS. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2011, and conflicting national standards shall be withdrawn at the latest by December 2011. Attention is drawn to the possibili
13、ty that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes CEN/TS 14780:2005. This document differs from CEN/TS 14780:2005 mainly as follows: a) results of
14、 interlaboratory tests are supplemented as informative annexes; b) new definitions for sampling are introduced; c) a method for determining the minimum number of increments for sampling is included; d) the whole document is restructured and editorially revised; e) decision schemes are updated; f) up
15、dated normative references are included. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, G
16、ermany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 14780:2011EN 14780:2011 (E) 4 Introduction Biofuels are a major source of renewable ene
17、rgy. European Standards are needed for production, trade and use of solid biofuels. For sampling and sample preparation of biofuels the following European Standards can be used: EN 14778, Solid biofuels Sampling EN 14780, Solid biofuels Sample preparation This European Standard can be used in regard
18、 to production, controlling and analysis of solid biofuels in general. BS EN 14780:2011EN 14780:2011 (E) 5 1 Scope This European Standard describes methods for reducing combined samples (or increments) to laboratory samples and laboratory samples to sub-samples and general analysis samples and is ap
19、plicable to solid biofuels. The methods described in this European Standard may be used for sample preparation, for example, when the samples are to be tested for calorific value, moisture content, ash content, bulk density, durability, particle size distribution, ash melting behaviour, chemical com
20、position, and impurities. The methods are not intended to be applied to the very large samples required for the testing of bridging properties. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cit
21、ed applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 14588:2010, Solid biofuels Terminology, definitions and descriptions EN 14774-1, Solid biofuels Determination of moisture content Oven dry method Part 1: Total moisture Reference
22、method EN 14774-2, Solid biofuels Determination of moisture content Oven dry method Part 2: Total moisture Simplified procedure 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 14588:2010 and the following apply. 3.1 combined sample sample consisting o
23、f all the increments taken from a sub-lot NOTE The increments may be reduced by division before being added to the combined sample. 3.2 general analysis sample sub-sample of a laboratory sample having a nominal top size of 1 mm or less and used for a number of chemical and physical analyses 3.3 incr
24、ement portion of fuel extracted in a single operation of the sampling device 3.4 laboratory sample combined sample or a sub-sample of a combined sample for use in a laboratory 3.5 lot defined quantity of fuel for which the quality is to be determined NOTE See also sub-lot. 3.6 moisture analysis samp
25、le sample taken specifically for the purpose of determining total moisture according to EN 14774-1 and EN 14774-2 BS EN 14780:2011EN 14780:2011 (E) 6 3.7 nominal top size aperture size of the sieve used in CEN, method for determining the particle size distribution of solid fuels, through which at le
26、ast 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 material, representative of a larger quantity for which the quality is to be determined 3.10 sample division division of a sample or sub-sample to a
27、appropriate size. This usually always leads to a mass reduction of a sample or sub-sample 3.11 size analysis sample sample taken specifically for the purpose of determining particle size distribution 3.12 sub-lot part of a lot for which a test result is required 3.13 sub-sample portion of a sample 3
28、.14 test portion sub-sample either of a laboratory sample or a test sample 3.15 test-sample laboratory sample after an appropriate preparation made by the laboratory 4 Symbols and abbreviations Mpis the moisture loss, in percentage msample,1 is the initial mass of the sample, g msample,2 is the mass
29、 of the sample after pre-drying, g W is the width and is at least 2,5 times the nominal top size of the material 5 Principles of correct sample reduction 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 samp
30、le. The main principle for sample reduction is that the composition of the sample as taken on site shall not be changed during each stage of the sample preparation. Each sub sample shall be representative of the original sample. To reach this goal every particle in the sample before sample division
31、shall have an equal probability of being included in the sub-sample following sample division. Two basic methods are used during the sample preparation. These methods are: sample division; particle size-reduction of the sample. BS EN 14780:2011EN 14780:2011 (E) 7 CAUTION Avoid loss of moisture and f
32、ine particles during milling and other operations. Because of the risk of changes in the moisture content (loss of moisture), a sub-sample (moisture analysis sample) shall be separated at the earliest possible stage of the sample preparation procedure. As an alternative, a separate moisture analysis
33、 sample may be taken. The sample reduction shall be carried out by a procedure that does not conflict with requirements of EN 14774-1 or EN 14774-2. For materials that have to be examined for moisture content, care shall be taken to avoid any significant heat build-up and risk of drying. 6 Apparatus
34、 6.1 Apparatus for sample division 6.1.1 General Sample division is the process of reducing the mass of the sample without reducing the size of the particles. This subclause gives some suitable apparatus for this purpose. To determine the correct use of each apparatus for different purposes refer to
35、 Clause 8. 6.1.2 Riffle boxes A riffle box shall have an equal number of slots and at least 6 at each side (preferably more if possible), with adjacent slots directing material into different sub-samples, and the width of the slots shall be at least 2,5 times the nominal top size of the material to
36、be riffled (see Figure 1). Key 1 W - slot width is at least 2,5 times the nominal top size of the material Figure 1 Example of a riffle box 6.1.3 Rotary sample dividers The inner dimensions of the equipment where the sample is fed shall be at least 2,5 times as wide as the nominal top size of the ma
37、terial to be processed. The rotary sample divider shall have a feeder device adjusted, so that the number of compartments multiplied by the number of rotations shall not be less than 120 while the sample is being divided. See Figure 2 for an example of a rotating divider. BS EN 14780:2011EN 14780:20
38、11 (E) 8 Key 1 feeder 2 funnel 3 rotating receivers 4 divided sample Figure 2 Example of a rotary sample divider 6.1.4 Shovels and scoops A shovel or scoop are tools used for manual sample division. They shall have a flat bottom, with edges raised high enough to prevent particles rolling off, and be
39、 at least 2,5 times as wide as the nominal top size of the material to be processed. See Figures 3 and 4 for examples of a scoop and a shovel respectively. Key 1 W width of the scoop Figure 3 Example of a scoop BS EN 14780:2011EN 14780:2011 (E) 9 Figure 4 Example of a shovel NOTE For very large samp
40、le sizes, it is more practical to use a push dozer or bulldozer or any other heavy machinery that has a large “scoop“ with raised edges. 6.2 Apparatus for particle size-reduction CAUTION When analysing metals, take care that there is no contamination from the sample preparation or reduction equipmen
41、t. 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 biofuel and the analyses to be performed). Drying of the material during coarse cutting should be avoided, by limiting heat production and air flow
42、through the material. 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. NOTE To prevent losses of moisture during particle size reduction a grinder with as low a grinding speed as possible is preferred. 6.2.2 C
43、utting mill Cutting mills are used for reducing the nominal top size of materials used as biofuels from about 10 mm to 30 mm down to about 1 mm or less (depending on the biofuel and the analyses to be performed). The mill shall be provided with screens of various aperture sizes covering this range,
44、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 quant
45、ities 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 th
46、e pre-grinding with cutting type mills. BS EN 14780:2011EN 14780:2011 (E) 10 6.2.3 Axe An axe is used for cutting wood logs or coarse material down to maximum 30 mm thickness or suitable size to be processed in a cutting mill provided with a 30 mm sieve. 6.2.4 Hand saw A hand saw is used to saw off
47、wood logs or coarse material down to maximum 30 mm thickness or suitable size to be processed in a cutting mill provided with a 30 mm sieve. NOTE A chain saw may contaminate the sample by chain oil and should therefore not be used. A saw machine should not be used for size reduction to avoid the ris
48、k of losing moisture in the sample as a result of heat caused by friction. 6.3 Sieves A wire-mesh sieve with an aperture size of 1,00 mm is required to check the nominal top size of general analysis samples. A wire-mesh sieve with an aperture size of 0,25 mm will be required if sub-samples with this
49、 nominal top size are required. 6.4 Balance A balance is required that is capable of determining the mass of samples to an accuracy of 0,1 % of the sample mass, and the mass of sub-samples to an accuracy of 0,1 % of the sub-sample mass. 7 Sample reduction general principles For every sample division stage to be carried out it is important that a sufficient mass of material is retained, otherwise the sub-samples produced or the test portions to be taken may not be representative of the
