1、INTERNATIONAL STANDARD IS0 10752 First edition 1994-05-l 5 Coal sizing equipment - Performance evaluation Charbon - iquipement pour la granulom b) classifiers; c) others. The procedure described in this International Standard applies to two-product separations. Performance as- sessment of multiprodu
2、ct separations can be achieved by consideration of a series of two-product separations. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publica- tion, the editions indicated
3、were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the standards indicated below. Members of IEC and IS0 maintain registers of cur- rently valid Inte
4、rnational Standards. IS0 1170:1977, Coal and coke - Calculation of ana- lyses to different bases. IS0 1213-1:1993, Solid mineral fuels - Vocabulary - Part 7: Terms relating to coal preparation. IS0 1953: 1972, Hard coals - Size analysis. IS0 1988: 1975, Hard coal - Sampling. 3 Definitions For the pu
5、rposes of this International Standard, the definitions given in 1213-1 and the following defi- nitions apply. 3.1 General 3.1.1 actual 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
6、the reference size. 3.1.3 finer material: Material that is finer than the reference size. 3.1.4 product: Material discharged from the sizing equipment prior to any further treatment or recircu- lation. 3.1.5 coarser product (cl: That product of size sep- aration that contains a greater proportion of
7、 coarser material than does the feed. 3.1.6 finer product (f): That product of size separ- ation that contains a greater proportion of finer ma- terial than does the feed. 3.1.7 sharpness of separation: An assessment of the deviation from a perfect separation, usually ex- pressed in terms of mean pr
8、obable error (ED,). 1 IS0 10752:1994(E) 0 IS0 3.2 Performance parameters 3.2.1 theoretical yield (sizing): The maximum yield of a product at a reference size, as determined from the size distribution curve for the reconstituted feed. 3.2.2 coarser material placement efficiency (EC): The percentage o
9、f coarser material in the reconsti- tuted feed that reports to the coarser product. 3.2.3 finer material placement efficiency (4): The percentage of finer material in the reconstituted feed that reports to the finer product. 3.2.4 overall separation index: The sum of the coarser material placement e
10、fficiency and the finer material placement efficiency minus 100. 4 Performance criteria The following criteria should be determined where applicable: al feed rate; bl reference size of separation; c) sharpness of separation; d) misplaced material; e) material placement efficiencies; f) the degree of
11、 difficulty of separation; g) material characteristics. NOTES 1 The above criteria will be influenced by test conditions which should therefore be fully reported. 2 It is essential that prediction of separation results takes into account the influence of test conditions. 3 It is essential that test
12、conditions are made compatible to ensure valid comparisons. 4 Conditions should be kept uniform during a test. 5 Performance parameters For the standard expression of performance of a sep- aration, the criteria in clause 4 should be determined by the following parameters: a) the feed rate, expressed
13、 on mass and/or volume bases; b) the reference size, preferably expressed as both partition size and equal errors size; NOTE 5 It is recognized that partition size is not al- ways obtainable from the results of a size separation and that an alternative reference size therefore has to be employed. To
14、 allow comprehensive comparison of performance, it is recommended that parameters based on equal errors size as the reference be included, in addition to those based on partition size. c) the sharpness of separation, expressed in terms of probable error; d) the distribution of misplaced material in
15、each product, presented graphically with respect to size, and the particular values of misplaced ma- terial in each product on both feed and product bases, each determined at the reference size of separation; e) the material placement efficiencies expressed as 1) coarser material placement efficienc
16、y (EC), 2) finer material placement efficiency (Q, 3) overall separation index derived from 1) and 2); f) the degree of difficulty of separation, expressed in terms of near-size material; g) other relevant characteristics of the feed material. 6 Performance test procedures The equipment to be tested
17、, the actual feed compo- sition, and the means of handling the feed and prod- ucts vary widely. A single standard procedure is not applicable. The following general recommendations are a) made. The average feed rate and/or product flow rates should be determined by the most accurate method possible
18、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 during the test; 2) continuous assessment by means of a cali- brated belt weigher or flowmeter and inte- gration during the test; 3) weighing ti
19、med increments taken at regular intervals during the test. IS0 10752:1994(E) b) Samples should be taken from the actual feed and from each of the products. Sampling techniques, initial number of increments and minimum mass of each increment should be chosen so that all samples taken are representati
20、ve. Sampling tech- niques, initial number of increments and minimum mass of increment for solids being conveyed by a fluid should comply with existing International Standards if available; for solids under other con- ditions, IS0 1988 applies. NOTE 6 Representative samples should be taken from all r
21、elevant streams to and from the equipment to be tested, to facilitate checking of results and assess- ment of the effects of degradation. c) It is essential to determine the feed rate and the actual yield of each product on a dry basis in ac- cordance with IS0 1170. This should be achieved in accord
22、ance with one of the following pro- cedures. 1) The mass of each product should be deter- mined by one or more of the following meth- ods: a. direct weighing of the whole of each product collected over the duration of the test or through continuous weighing and integration over the duration of the t
23、est; b. taking regular timed increments over the duration of the test; c. weighing each product collected simul- taneously over a selected timed period during the test. NOTES 7 The methods given in 1) are listed in order of reliability. 8 If it is feasible to measure both the mass of the feed (by be
24、lt weigher, weigh hopper, flowmeter, etc.) and the mass of the products, this provides a check. 9 If the mass of one of the products cannot be measured, it can be obtained from a mass balance between the feed and products. 10 Where the solids are conveyed by a fluid, it may be more convenient to mak
25、e volumetric measurements, 11 Representative samples should be taken from relevant streams to determine moisture contents or concentrations of solids as appropriate, so that the results can be reported on a dry basis. 21 In circumstances that prevent the weighing of sufficient streams, size analyses
26、 of feed and products can be used to determine the percentage yield of each product, as de- scribed in annex A. NOTE 12 In all circumstances, the method used to de- termine the actual yield of each product should be reported with each respective value in table 3. 7 Analytical procedures The method a
27、nd 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 compatible terms. For example, the results of size analysis by sieving would be compatible with vibrating screens, and the results of size an
28、alysis by a series of small cyclones would be compatible with cyclone separators. Size analysis by sieving should be carried out in accordance with IS0 1953. The method 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 fee
29、d 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 exceed 2:l for each size fraction. It is recommended that this ratio for size limits be reduced to J- 2 :l for a mini- mum of two fractions, both above and bel
30、ow the ref- erence size. NOTES 13 J- In some circumstances, a ratio of size limits closer than 2 :l may be necessary in the region of the reference size, to ensure that each of the size fractions contains not more than 10 % of the samole. 74 Size distribution curves for the products can be used for
31、a) providing data for additional partition coefficients; b) averaging analytically determined values to improve the derived partition curve. 8 Evaluation and presentation of performance characteristics 8.1 General All data shall be evaluated and presented in one data sheet, three tables and three fi
32、gures as follows: a) data sheet - test and equipment data; 3 IS0 10752:1994(E) (5 IS0 b) c) d) e) f) 9) table 1 - size distribution of feed and products; table2 - partition coefficients and misplaced material data; table3 - statement of sizing equipment per- formance; figure 1 - partition curve; fig
33、ure2 - size distribution curve for the recon- stituted feed; figure3 - misplaced material curves. The presentation of the test data may be accom- plished by the procedure described below. The specified tabular and graphical formats are given in clause 9. Specific worked examples are included in anne
34、xes B, C and D. NOTES 15 Primary calculation procedures are shown in tables 1 and 2. A column number in parentheses denotes a respec- tive value taken from that column. 16 The origins of plotted values are shown in figures 1 and 2 by reference to table and column numbers. 17 Reference to definitions
35、 of performance parameters in clause 3 supports the brief explanation of their derivation given in relevant subclauses and in tables 1 and 2. 8.2 Basic data The data obtained from a performance test comprise the size analyses of the actual feed and the coarser and finer products and the proportion o
36、f material re- porting to each product. These basic data are com- piled in table 1, columns 1 to 8, and calculated on a reconstituted feed basis in columns 9 to 12. 8.3 Reconstituted feed size distribution The size distribution curve for the reconstituted feed is constructed as shown in figure2, by
37、plotting the cumulative percent less than the upper size limit (col- umn 12 of table 1) against the upper size limit (column 1 of table 1). NOTE 18 It is convenient to use a logarithmic scale for particle size when plotting size distribution curves, to cover a wide range of sizes and to cater for si
38、ze limits that are in geometric progression. 8.4 Partition curve The partition curve is constructed as shown in figure 1, by plotting the value of each partition co- efficient against the corresponding mean size. It is recommended that each size fraction be represented by its geometric mean size. Ge
39、ometric mean sizes and partition coefficients are calculated in table2, col- umns 13 and 14. The recommended scales are size: log, 1 cycle = 50 mm partition coefficient: 1 % = 2 mm NOTES 19 As an alternative to geometric mean size, each size fraction may be represented by its mid-mass particle size,
40、 derived from a known functional relationship or estimated from the reconstituted feed curve. 20 As an alternative method of construction, partition co- efficients can be plotted as a histogram on a reconstituted feed base, producing an area representative of mass. An intermediate curve is then draw
41、n by equalizing areas within each size fraction. Performance parameters are derived by applying values obtained from the intermediate curve to the size distribution curve for the reconstituted feed. 8.5 Partition size The partition size, S, is obtained directly from the partition curve and is entere
42、d as a performance par- ameter in the statement of sizing equipment per- formance in table3. NOTE 21 The partition size can be determined from the misplaced material curves (figure31 at the minimum value of total misplaced material. 8.6 Sharpness of separation The 25 %, Szs, and 75 %, S,s, intercept
43、s are each read from the partition curve (figure 1) and are entered as primary parameters in the statement of sizing equip- ment performance in table 3. For symmetrical partition curves, the sharpness of separation may be ex- pressed in terms of the mean probable error (.!$,) as follows: qxll = h5 - s25 2 . . . (1) In the more common case of skewed partition curves, the sharpness of separation may be expressed in terms of the upper and lower probable errors as fol- lows: Upper probable error = S, - S, 4
