1、BRITISH STANDARD BS7787:1994 ISO10752: 1994 Method for Evaluation of the performance of coal sizing equipment UDC621.928.2.004.15:662.66BS7787:1994 This British Standard, having been prepared under the directionof the Solid Mineral Fuels Standards Policy Committee, was published underthe authority o
2、ftheStandards Board and comes into effect on 15 September1994 BSI11-1999 The following BSI references relate to the work on this standard: Committee reference SFI/5 Draft for comment90/52204DC ISBN 0 580 23274 3 Committees responsible for this British Standard The preparation of this British Standar
3、d was entrusted by the Solid Mineral Fuels Standards Policy Committee (SFI/-) to Technical Committee SFI/5, upon which the following bodies were represented: British Coal Corporation Coal Preparation Plant Association Low Temperature Coal Distillers Association of Great Britain Ltd. Minerals Enginee
4、ring Society Amendments issued since publication Amd. No. Date CommentsBS7787:1994 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Performance criteria 2 5 Performance parameters 2 6 Performance test proc
5、edures 2 7 Analytical procedures 3 8 Evaluation and presentation of performance characteristics 3 9 Tabular and graphical presentation 5 Annex A (normative) Calculation of the yield of each product of a size separation from size analyses of feed and product materials 12 Annex B (informative) Worked
6、example Vibrating screen 14 Annex C (informative) Worked example Cyclone 21 Annex D (informative) Worked example Deduster 28 Figure 1 Partition curve 8 Figure 2 Size distribution curve for the reconstituted feed 9 Figure 3 Misplaced material curves 10 Figure B.1 Partition curve (vibrating screen) 17
7、 Figure B.2 Size distribution curve for the reconstituted feed (vibrating screen) 18 Figure B.3 Misplaced material curves (vibrating screen) 19 Figure C.1 Partition curve (cyclone) 24 Figure C.2 Size distribution curve for the reconstituted feed (cyclone) 25 Figure C.3 Misplaced material curves (cyc
8、lone) 26 Figure D.1 Partition curve (deduster) 31 Figure D.2 Size distribution curve for the reconstituted feed (deduster) 32 Figure D.3 Misplaced material curves (deduster) 33 Table 1 Size distribution of feed and products 6 Table 2 Partition coefficients and misplaced material data 7 Table 3 State
9、ment of sizing equipment performance 11 Table B.1 Size distribution of feed and products (vibrating screen) 15 Table B.2 Partition coefficients and misplaced material data (vibrating screen) 16 Table B.3 Statement of sizing equipment performance (vibrating screen) 20 Table C.1 Size distribution of f
10、eed and products (cyclone) 22 Table C.2 Partition coefficients and misplaced material data (cyclone) 23 Table C.3 Statement of sizing equipment performance (cyclone) 27 Table D.1 Size distribution of feed and products (deduster) 29 Table D.2 Partition coefficients and misplaced material data (dedust
11、er) 30 Table D.3 Statement of sizing equipment performance (deduster) 34BS7787:1994 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of the Solid Mineral Fuels Standards Policy Committee and is identical with ISO10752:1994 Coal sizing equipment Performance
12、 evaluation published by the International Organization for Standardization (ISO), in the preparation of which the UnitedKingdom played a full part. A British Standard related to ISO1170:1977 is BS1016 Methods for analysis and testing of coal and coke Part100:1994 General introduction and methods fo
13、r reporting results. A British Standard related to ISO1988:1975 is BS1017-1:1989 Methods for sampling of coal. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a Britis
14、h Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard ISO1213-1:1993 BS3552:1994 Glossary of coal preparation terms (Identical) ISO1953:1972 a BS1016 Methods for analysis and testing of coal and coke Part17:1979 S
15、ize analysis of coal (Technically equivalent) a ISO1953:1972 has been superseded by ISO1953:1994, which will be implemented in the U.K. as BS1016-109. On publication of BS1016-109, BS1016-17 will be withdrawn. Summary of pages This document comprises a front cover, an inside front cover, pagesi andi
16、i, pages1 to34 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS7787:1994 BSI 11-1999 1 1 Scope This International Standard describes the principles and methods fo
17、r the expression of results of performance tests on sizing equipment used in coal preparation, and includes methods for the evaluation of performance parameters. Performance test procedures and size measurement techniques are recommended. This International Standard applies to all types of sizing eq
18、uipment, categorized as follows: a) screens; b) classifiers; c) others. The procedure described in this International Standard applies to two-product separations. Performance assessment of multiproduct separations can be achieved by consideration of a series of two-product separations. 2 Normative r
19、eferences The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Internationa
20、l Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO1170:1977, Coal and coke Calculation of analyses to different bases. ISO1213-1:1993
21、, Solid mineral fuels Vocabulary Part1: Terms relating to coal preparation. ISO1953:1972, Hard coals Size analysis. ISO1988:1975, Hard coal Sampling. 3 Definitions For the purposes of this International Standard, the definitions given in1213-1 and the following definitions apply. 3.1 General 3.1.1 a
22、ctual feed (F) material fed to the sizing equipment during the test period and including any recirculated material 3.1.2 coarser material material that is coarser than the reference size 3.1.3 finer material material that is finer than the reference size 3.1.4 product material discharged from the si
23、zing equipment prior to any further treatment or recirculation 3.1.5 coarser product (c) that product of size separation that contains a greater proportion of coarser material than does the feed 3.1.6 finer product (f) that product of size separation that contains a greater proportion of finer mater
24、ial than does the feed 3.1.7 sharpness of separation an assessment of the deviation from a perfect separation, usually expressed in terms of mean probable error (E pm ) 3.2 Performance parameters 3.2.1 theoretical yield (sizing) the maximum yield of a product at a reference size, as determined from
25、the size distribution curve for the reconstituted feed 3.2.2 coarser material placement efficiency (E c ) the percentage of coarser material in the reconstituted feed that reports to the coarser product 3.2.3 finer material placement efficiency (E f ) the percentage of finer material in the reconsti
26、tuted feed that reports to the finer product 3.2.4 overall separation index the sum of the coarser material placement efficiency and the finer material placement efficiency minus100BS7787:1994 2 BSI 11-1999 4 Performance criteria The following criteria should be determined where applicable: a) feed
27、rate; b) reference size of separation; c) sharpness of separation; d) misplaced material; e) material placement efficiencies; f) the degree of difficulty of separation; g) material characteristics. NOTE 1The above criteria will be influenced by test conditions which should therefore be fully reporte
28、d. NOTE 2It is essential that prediction of separation results takes into account the influence of test conditions. NOTE 3It is essential that test conditions are made compatible to ensure valid comparisons. NOTE 4Conditions should be kept uniform during a test. 5 Performance parameters For the stan
29、dard expression of performance of a separation, the criteria in clause4 should be determined by the following parameters: a) the feed rate, expressed on mass and/or volume bases; b) the reference size, preferably expressed as both partition size and equal errors size; NOTE 5It is recognized that par
30、tition size is not always obtainable from the results of a size separation and that an alternative reference size therefore has to be employed. To allow comprehensive comparison of performance, it is recommended that parameters based on equal errors size as the reference be included, in addition to
31、those based on partition size. c) the sharpness of separation, expressed in terms of probable error; d) the distribution of misplaced material in each product, presented graphically with respect to size, and the particular values of misplaced material in each product on both feed and product bases,
32、each determined at the reference size of separation; e) the material placement efficiencies expressed as 1) coarser material placement efficiency (E c ), 2) finer material placement efficiency (E f ), 3) overall separation index derived from1) and2); f) the degree of difficulty of separation, expres
33、sed in terms of near-size material; g) other relevant characteristics of the feed material. 6 Performance test procedures The equipment to be tested, the actual feed composition, and the means of handling the feed and products vary widely. A single standard procedure is not applicable. The following
34、 general recommendations are made. a) The average feed rate and/or product flow rates should be determined by the most accurate method possible in the particular circumstances. Typical procedures that may be used are 1) direct assessment of the mass and/or volume of the whole of the feed or product
35、during the test; 2) continuous assessment by means of a calibrated belt weigher or flowmeter and integration during the test; 3) weighing timed increments taken at regular intervals during the test. b) Samples should be taken from the actual feed and from each of the products. Sampling techniques, i
36、nitial number of increments and minimum mass of each increment should be chosen so that all samples taken are representative. Sampling techniques, initial number of increments and minimum mass of increment for solids being conveyed by a fluid should comply with existing International Standards if av
37、ailable; for solids under other conditions, ISO1988 applies. NOTE 6Representative samples should be taken from all relevant streams to and from the equipment to be tested, to facilitate checking of results and assessment of the effects of degradation. c) It is essential to determine the feed rate an
38、d the actual yield of each product on a dry basis in accordance with ISO1170. This should be achieved in accordance with one of the following procedures. 1) The mass of each product should be determined by one or more of the following methods: a. direct weighing of the whole of each product collecte
39、d over the duration of the test or through continuous weighing and integration over the duration of the test; b. taking regular timed increments over the duration of the test; c. weighing each product collected simultaneously over a selected timed period during the test. NOTE 7The methods given in1)
40、 are listed in order of reliability. NOTE 8If it is feasible to measure both the mass ofthe feed (by belt weigher, weigh hopper, flowmeter,etc.)and the mass of the products, this provides a check.BS7787:1994 BSI 11-1999 3 NOTE 9If the mass of one of the products cannot be measured, it can be obtaine
41、d from a mass balance between the feed and products. NOTE 10Where the solids are conveyed by a fluid, it may be more convenient to make volumetric measurements. NOTE 11Representative samples should be taken from relevant streams to determine moisture contents or concentrations of solids as appropria
42、te, so that the results can be reported on a dry basis. 2) In circumstances that prevent the weighing of sufficient streams, size analyses of feed and products can be used to determine the percentage yield of each product, as described in Annex A. NOTE 12In all circumstances, the method used to dete
43、rmine the actual yield of each product should be reported with each respective value in Table 3. 7 Analytical procedures The method and procedure of size analysis should be selected, as far as possible, to be in agreement with the principle of the equipment under test, to produce results in compatib
44、le terms. For example, the results of size analysis by sieving would be compatible with vibrating screens, and the results of size analysis by a series of small cyclones would be compatible with cyclone separators. Size analysis by sieving should be carried out in accordance with ISO1953. The method
45、 and apparatus used, and the basis of the percentages (by mass or volume), shall be stated in the data sheet and in Table 1. The feed sample and each of the product samples should be subjected to size analyses in which the ratio of the upper and lower size limits does not exceed2:1 for each size fra
46、ction. It is recommended that this ratio for size limits be reduced tofor a minimum of two fractions, both above and below the reference size. NOTE 13In some circumstances, a ratio of size limits closer thanmay be necessary in the region of the reference size, to ensure that each of the size fractio
47、ns contains not more than10% of the sample. NOTE 14Size distribution curves for the products can be used for a) providing data for additional partition coefficients; b) averaging analytically determined values to improve the derived partition curve. 8 Evaluation and presentation of performance chara
48、cteristics 8.1 General All data shall be evaluated and presented in one data sheet, three tables and three figures as follows: a) data sheet test and equipment data; b) Table 1 size distribution of feed and products; c) Table 2 partition coefficients and misplaced material data; d) Table 3 statement
49、 of sizing equipment performance; e) Figure 1 partition curve; f) Figure 2 size distribution curve for the reconstituted feed; g) Figure 3 misplaced material curves. The presentation of the test data may be accomplished by the procedure described below. The specified tabular and graphical formats are given in clause9. Specific worked examples are included in Annex B, Annex C and Annex D. NOTE 15Primary calculation procedures are shown in Table 1 and Table 2. A column number in parentheses denotes a re
