1、 Intentionally left blank Pulverizers Supplement to Performance Test Code for Steam Generating Units, PTC 4.1 PERFORMANCE TEST CODES Library of Congress Catalog No. 70-77829 No part of this document may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior writ
2、ten permission of the publisher. Copyright, 1969, by The American Society of Mechanical Engineers Printed in. the United States of America FOREWORD In 1937 the American Boiler Manufacturers and Affiliated Industries Asso- ciation approached the ASME Performance Test Codes Committee with the request
3、for the development of a Code on the testing of coal pulverizers. After discussion of this problem by the standing Performance Test Codes Committee, the scope of the Performance Test Code Committee No. 4 on Station- ary Steam-Generating Units was expanded to cover the performance characteris- tics o
4、f equipment such as coal pulverizers and other fuel burning apparatus. A preliminary draft of the Code PTC 4.1 was distributed for comment and criticism in January, 1941. Notification of completion of this code appeared in the May, 1943, issue of Mechanical Engineering. At the December 3, 1943, meet
5、- ing of the standing Committee it was approved and adopted by the Council on May 16, 1944. In May, 1958, Performance Test Code Committee No. 4 was reorganized and instructed to rewrite and bring up to date the Performance Test Code for Steam Generating Units, PTC 4.1, and its Supplement, the Test C
6、ode for Coal Pulver- izers, PTC 4.2. Later these instructions were extended to include a new Supple- ment, the Test Code for Air Heaters, PTC 4.3. The revised Test Code for Coal Pulverizers PTC 4.2 1969 was approved by the Performance Test Codes Committee on March 15, 1968. The revised PTC 4.1 was a
7、pproved and adopted by the Council of the Soc- iety by action of the Policy Board, Codes and Standards, on June 24, 1964; the revised PTC 4.2 1969 on October 28, 1968; and PTC 4.3 on November 8, 1967. 3 Intentionally left blank PERSONNEL OF PERFORMANCE TEST CODE COMMITTEE NO. 4 ON STATIONARY STEAM-G
8、ENERATING UNITS John M, Driscoll, Chairman John V. Cleary, Jr., Secretary James U Baley, General Superintendent, Electric Operations, Baltimore Gas and Electric Company, Gas and Electric Building, Baltimore, Maryland, 21203 Charles D. Birget, formerly Chief Mechanical Engineer, Commonwealth Associat
9、es, Inc., 209 E. Washing- ton Avenue, Jackson, Michigan, 49201 John A. Bostic, General Supervising Engineer, Civil and Mechanical Engineering Department, The Cleveland Electric Illuminating Company, Box 5000, Cleveland, Ohio, 44101 Hugh J. Byrne, Steam-Power Engineer, Central Engineering Office, Cro
10、wn Zellerbach Corporation, 6363 Airport Way, Seattle, Washington, 98108 John Vu Cleary, Jr., Chief Cost Engineer, Cost Engineering Bureau, Consolidated Edison Company of New York, Inc., 4 Irving Place, New York, New York, 10003 Leonard Cohen, Head, Operation Management Department, Naval Ship Enginee
11、ring Center, Philadelphia Division, U.S. Nava! Base, Philadelphia, Pennsylvania, 19112 John M. Driscoll, Chief Mechanica! Engineer, Consolidated Edison Company of New York, Inc., 4 Irving Place, New York, New York, 10003 John H. Fernandes, Chief Project Engineer, Product Diversification Dept., Combu
12、stion Engineering, Inc., Prospect Hill Road, Windsor, Connecticut, 06095 William Z. Harper, Assistant Superintendent, Utilities Division, Kodak Park Works, Eastman Kodak Company, Rochester, New York, 14604 Edward C. Kistner, Engineer in Charge of Power Plant Section, Mechanical Engineering Division,
13、 Philadelphia Electric Company, 9th and Sansom Streets, Philadelphia, Pennsylvania, 19105 Frank C. Lisevick, Mechanical Engineer, Stone ti Webster, Inc., 225 Franklin St., Boston, Massachusetts, 02107 Robert A. Lorenzini, Senior Vice-president, Foster Wheeler Corporation, 110 South Orange Avenue, Li
14、vingston, New Jersey, 07039 John F. McLaughlin, Jr., Manager, Production Engineering, Power Production Engineering, Union Electric Company, 315 North 12th Boulevard, St. Louis, Missouri, 63101 Silas L. Morse, Assistant Manager Field Engineering, The Babcock also of the return and vented air in stora
15、ge systems. 4.1.16 Vent loss (storage system). 4.1.17 Power to drive pulverizer, fans, feeder, (cyclone air lock in storage systems). 4.2 Instruments and Apparatus. The instru- ments and apparatus required for pulverizer tests are: 4.2.01 Scales for weighing coal - Individual automatic scales includ
16、ed in the pulverizing system may be used for weighing fuel before delivery to the feed hopper. Automatic scales shall be calibrated for accuracy and reliability and balanced after each dump. 4.2.02 Calibrated coal feeders - Where the degree of accuracy is adequate for the purpose of the test, calibr
17、ated coal feeders may be used to determine the coal weight. 4.2.03 Round-hole screens - For sizing coal to the pulverizer the screen to be used shall cbmply with the Test Code for Solid Fuels, PTC 3.2. 4.2.04 Airtight containers for raw coal and pul- verized coal samples-Containers for individual co
18、al samples for moisture determination shall be non- corrosive, nonabsorbent and air-tight. Other samples such as for feed size and grindability determination may be placed in large clean drums or bins with covers to prevent accidental contamination. 4.2.05 Pulverized coal sampling equipment - Sieves
19、 for determining fineness of pulverized fuel should be 50, 100, 200 mesh U.S. standard sizes. Sampling equipment and arrangement are detailed iti Par. 5.4. All sieves shall comply with the Test Code for Solid Fuels, PTC 3.2. 4.2.06 Means for determining air temperatures and humidities - Calibrated t
20、hermometers or calibrated thermocouples with potentiometer shall be used for measuring temperatures. Humidi- ties shall be determined with a psychrometer. 4.2.07 Means for measuring air pressure - U-tubes or inclined gages for determining pressure shall be filled with water or a liquid of known spec
21、ific gravity. 4.2.08 Means for measuring air quantities - Air flows may be measured by calibrated pitot tubes or flow meters. (see Par. 5.5) 16 COAL PULVERIZERS 42.09 Sampling equipment for determining dust Determination of power from a steam turbine re- loading in vented air - For storage systems,
22、vent quires the use of steam flowmeters, and pressure losses shall be measured, see Par. 5.6. and temperature measuring devices (see Par. 5.2). Directions regarding the characteristics, use, 4.2.10 Instruments for determining power input to and calibration of most of this apparatus are given motor o
23、r turbine drives - Electric power may be in the ASME Performance Test Codes Supplement measured by calibrated wattmeters or watthour on Instruments and Apparatus (PTC 19). meters. 17 ASME PERFORMANCE TEST CODES SECTION 5, MEASUREMENTS 5.1 Coal Weighing 5.1.1. Coal shall be weighted as delivered to t
24、he pulverizer. The pulverizer capacity shall be taken as the average weight per hour of coal fed to the pulverizer over the test period. The rate of coal fed to the pulverizer shall be maintained as uniform as possible over the test period and recorded at regular intervals. 5.1.2 A feeder may be use
25、d to determine the weight of coal if the feeder can be calibrated. 5.1.3 Weighing procedure shall be as established in Pars. 4.2.01 and 4.2.0 2. Where automatic coal scales or calibrated feeders are used, the actual number of dumps shall be counted for the exact time of test, or integrators shall be
26、 read at the precise time for starting and stopping the test. 5.2 Power Measurements 5.2.1 The power input to electric motors shall be determined from readings of calibrated indicat- ing, integrating, or recording wattmeters over the period included between the starting and stopping time of each tes
27、t. 5.2.2 Procedures for obtaining power measurements are as set forth in thesupplement on Instruments and Apparatus, Electric Measurements in Power Cir- cuits, PTC 19.6. Calculations of brake horse- power output shall be based on motor efficiency curves for the particular motor. Where extreme ac- cu
28、racy of brake horsepower output of fan or pulverizer drive motors is required, then the test procedure as set forth in ASA Code C 50-20, Test Code for Polyphase Induction Motors and Generators, shall be used. 5.2.3 In the case of a steam turbine, the formula for obtaining shaft power is: Hourly stea
29、m flow x (Enthalpy of inlet steam-Isentropic en- Brake horsepower = thalpy of exhaust steam) x Over-all turbine efficiency - Where 2545 Steam flow is the metered flow in pounds per hour. Enthalpy of inlet steam is the enthalpy at inlet pressure and temperature and percent mois- ture if not superheat
30、ed. Isentropic enthalpy of exhaust steam is the enthalpy-at exhaust pressure and initial entropy. Overall efficiency is to be obtained from cali- brated performance curves for the particular steam turbine. 2545 is the number of Btu per horsepower hour. As an alternative to the above, the parties to
31、the test may agkee upon the necessary methods of measurements, which shall be fully described in the test report. 5.3 Raw Coal Sompling 5.3.1 Samples for Moisture Determination. A rep- resentative sample of raw coal shall be taken every 15 minutes and shall be obtained in accordance with the Test Co
32、de for Solid Fuels, PTC 3.2. However, special sample for moisture determina- tion shall be separated from the general sample, quickly placed in a noncorrosive, non-absorbent, air-tight container and sealed immediately. This sample for moisture shall not be quartered or crushed prior to moisture dete
33、rmination in the laboratory. Every effort shall be made to avoid loss of moisture due to strong drafts at the point of sampling (such as may occur at a pulverizer feeder for example). The moisture of each individual sample shall be determined sep- arL STD. BRASS PIPE BRASS PIPE COUPLING SI LVER SOLD
34、ER FtG. 5 DETAIL OF SAMPLING TIP 20 COAL PULVERIZERS FIG. 6 DETAIL OF CYCLONE COLLECTOR 21 ASME PERFORMANCE TEST CODES -2 ZONES 5“ L 5“ PIPI 3 ZONES 6“ dr 7“ PIPE . v7.v 1 v7.9 4 ZONES 8“ dr 9“ PIPE 5 ZONES IO“ a II“ PIPE FIG. 7 SAMPLING DIRECT-FIRED PULVERIZED COAL-SAMPLING STATIONS DIMENSIONS ARE
35、“PERCENT OF PIPE DIA.“ 22 COAL PULVERI ZERS AVERAGE PARTICLE SIZE (INTERSECTION OF SIZE DISTRIBUTION LINE WITH 63.21% PASSING LINE) E r SLOPE OF S IZE 0 ISTR I BUT ION LINE (TANGENT OF ANGLE J N (From:Landers W.S and Reid w.TA Graphical Form for 4pplying the Rosin and Ramler Equation to the Size bis
36、t;:Oution oi Brokefl Coal: Bureau of Mines Inf.Circular 73U6. 1W6.) FIG. 8 GRAPHICAL FORM FOR REPRESENTING DISTRIBUTION OF SIZES OF BROKEN COAL 23 ASME PERFORMANCE TEST CODES The coal rate per fuel transport line should be 10,500 pounds per hour. The sample rate per minute for 100 per cent recovery
37、should then be: Sample rate - lb per minute 63000 - 6 , X 0.305 = 0.29 60 x 182.65 Sample for a three minute sampling period should then be 0.87 lb for 100 per cent recovery. If the recovery is between 90 and 110 per cent, the sample shall be considered satisfactory as to rate of collection. After t
38、aking one or two samples and weighing them, the aspirator can be adjusted to give a re- covery within the limits of 90 and 110 per cent. Any samples that do not represent 90 - 110 per cent recovery shall be discarded. line is so high that the recovery is above 110 per cent with all aspirator air shu
39、t off, the flow from the cyclone should be throttled to reduce the recovery to the desired range be- tween 90 and 110 per cent. This can be done by installing a valve or orifice at the cyclone collector vent discharge, (see Fig. 4). Samples shall be taken by carefully tiaversing at least two diamete
40、rs 90 degrees apart. The sampling time at each point shall be approximate- lyfive seconds. The pipe is divided by concen- tric circles into annular bands of equal areas and the sampling stations located at the center of each band on each side of the pipe. Figure 7 in- dicates the sampling zones for
41、various pipe sizes. If preliminary samples taken at each in- dividual line shows wide variations in fineness and recovery better locations should be used. The location shall preferably be in a vertical pipe as far as possible from preceding bends, changes of cross section or valves. A distance of 7
42、to 10 times the pipe diameter is desirable. Sampling connections shall be cleared of accumulated coal before taking samples. Also. it should be de- termined that there is no coating of coal on the inside of the coal pipe. Precautions should be taken to keep the samples above the dew point during col
43、lection. This may be accomplished by heating or insulat- ing the cyclone collector. When the sampling points are in the pipes and If the static pressure in the fuel transport of the samples from all the pipes should be com- pared with total coal weight, as in the example, to check the recovery. If t
44、he air velocity and static pressure in each fuel transport line are very nearly equal, the same cyclone throttle settin,g and the same air pressure at the aspirator should give about the same sample tip velocity. Then even if the coal is not equally distributed in the several pipes, duplicate cyclon
45、e throttle settings should result in samples from each p.ipe which will be approximately proportion- al in weight to the coal distribution, but the total should be between 90 and 110 per cent of the proportional total coal flow. Each sample may be screened separately and the weighted average used to
46、 obtain the average fineness of the pulverizer output, or the samples may be thorough- ly mixed and one screen determination made of the mixture, since the sample from each line represents the proper proportion of the pulverizer output. ples shal, . taken at the inlet of the pulver- ized coal bin. I
47、f the sampling location is under suction, the container should be provided with a cover which can be closed before it is withdrawn from the sampling connection. in a storage system shall be either the weighted average of the fineness of all samples taken dur- ing the test, or the fineness of the com
48、posite sample. 5.4.1 Samples for Moisture and Fineness Dettr- mination. As part of the procedure for fineness determination, the sample is first air dried and the moisture determined and noted. Samples shall be taken every 30 minutes. The procuring of the gross sample and laboratory determination sh
49、all be in accordance with the Test Code for Solid Fuels, PTC 3.2, Pars. 89 through 96. In storage type systems pulverized coal sam- The fineness of pulverized coal samples taken Fineness through at least 50, 100 and 200 mesh U.S. Standard screens should be plotted on a Rosin and Rammler chart (Fig. 8) to determine if samples are representative. Points should fall on a straight line. If the points do not fall on a straight line, the sample is not represent- ative and a new sample shall be obtained. 5.5 Measurement
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