1、! ASME PTC*LS.LO BL li 0759670 0051BOO 8 m This code or standard was developed under procedures accredited as meeting the criteria for American National Standards. The Consensus Committee that approved the code or standard was bal- anced to assure that individuals from competent and concerned intere
2、sts have had an opportunity to participate. The proposed code or standard was made available for public review and comment which provides an opportunity for additional public input from industry, academia, regulatory agencies, and the public-at-large. ASME does not “approve,“ “rate,“ or “endorse“ an
3、y item, construction, proprietary device, or activity. ASME does not take any position with respect for the validity of any patent rights asserted in con- nection with any items mentioned in this document, and does not undertake to ensure anyone utilizing a standard against liability for infringemen
4、t of any applicable Letters Patent, nor assume any such liability. Users of a code or standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Participation by federal agency repres
5、entativek) or personk) affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard. Date of Issuance: August 31, 1981 No part of this document may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written
6、 permission of the publisher. Copyright 01981 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A. “ FOREWORD The scope of the work of PTC Committee No. 19 on Instruments andApparatus is to describe the various types of instruments and methods of measurement likely t
7、o be pre- scribed in any of the ASME Performance T.est Codes. Such details as the limits and sources of error, method of calibration, precautions, etc., as will determine their range of applica- tion are given. Only the methods of measurement and instruments, including instructions for their use, sp
8、ecified in the individual test codes are mandatory. Other methods of measurement and instruments, that may be treated in the Supplements on Instruments and Apparatus, shall not be used unless agreeable to all the parties to the test. This Supplement on Instruments and Apparatus, Part 10 on Flue and
9、Exhaust Gas Analyses, replaces an older one published in 1968. This Edition was approved by the Supervisory Committee on May 15, 1978. It was approved and adopted by the American National Standards Institute as meeting the criteria for an American National Standard on August 17,1978. Following resci
10、ssion of a critical manual technique by the original source (ASTM) the -document was re-approved by the Supervisory Committee with an alternate manual technique on December 29, 1980 and re-adopted by the American National Standards Institute on June 18, 1981. ASME PTC*LS-LO 83 W 0757670 0053802 3 PE
11、RSONNEL 1 CE TEST CODE COMn OF PERFORMANl ON INSTRUMENTS AND APPARATUS FLUE AND EXHAUST GAS ANALYSES Daniel E. Carl, Chairman R. W. Robinson, Vice-chairman H, W. Blakeslee, Secretary AITTEE NO. 19.10 .r - H. W. Blakeslee, Environmental Engineer, Pipe i.e., extractive, in-situ, and remote. 2 03.2 The
12、 extractive approach has been the most utilized for systems measuring gaseous constituents from stationary sources. This pproach requires a sample probe, transport line, conditioning system, and analyzers. There are potential problems in the sampling aspects as well as the measure- ment. 2.03.3 The
13、spectrometric in-situ approach requires no sarhple conditioning. The concentrations are determined by the effects on a light (or other energy) source as it passes through the exhaust before impingement on a sensor. The source and sensor are both mounted directly on the stack. They can either be acro
14、s the stack from each other or colocated on one side with a reflector on the other side of the stack. Although there are no requirements for TABLE 1 Flue Gas Tests for Steam Generators Purpose of Test 1. Air Infiltration 2. Gas Stratification 3. Air Heater Leakage 4. Unit Efficiency 5. Excess Air 6.
15、 Pollution Determination 7. Tube Wastage Caused from Reducing Atmosphere 8, Scrubber Performance 9. Odor Control 10. Cold End Corrosion (Acid Dew Point) Probe Location Furnace and Boiler Outlet Furnace, Boiler Outlet, Duct, Stack Gas Entering and Leaving Air Heater Gas at Outlet of Unit (See PTC 4.1
16、) Economizer or Air Heater Outlet Stack or Exhaust Duct In Furnace at Wastage Area Inlet and Outlet of Scrub- ber Outlet of Unit Air Heater Inlet and Outlet - ASME PTC*LS*L 81 ES 0759670 005L808 2 INSTRUMENTS AND APPARATUS O sample conditioning with in-stack systems, moisture and of concentration at
17、 a distance from the source. This particulate in the exhaust can possibly cause interference. . method viU require more evaluations in various applica- 2.03.4 Remote sensing has been developed to enable pollu- that competes with either the extractive or the in-situ tions before it can be demonstrate
18、d as a viable technique - tion monitoring from satellite and to allow measurements methods. “ “ 5 ASME PERFORMANCE TEST CODES SECTION 3, EXTRACTIVE MEASUREMENT SYSTEMS 3.01 There are several considerations that must be made in preparation for an extractive measurement test. They should all be consid
19、ered or the test may be either under or over designed. These are: Purpose of the testing; including the required accuracy. The analytical technique to be used. Test plan to insure that the data collected fulfills the test requirements. The probe desigi and arrangement. The sample transport line and
20、sample condition- ing system. 3.02 Sampling Considerations 3.02. I Test Requirements 3.02.1. 1 Before a test can be started, the requirements of the test must be firmly established and suitable equip- ment chosen. In particular, the accuracy required must be determined and the type of test specified
21、; e.g., whether equipment that will monitor emissions over a period of years is required, whether the test is part of a performance test on the combustion equipment, or whether the test is to prove compliance with regulations. 3.02.1.2 The instrumented or manual analytical method should be chosen to
22、 span the entire range of expected gas concentrations. The highest possible concentration should not exceed the range of the method; ideally, the average concentrations should lie at 75 percent of the range. Several calibration points on the analytical system must be made to span the entire range of
23、 expected concentra- tions, as the minimum requirement. 3.02.2 Instrumental or Manual 3.02.2.1 The first choice to be made in an extractive system is between manual (normally wet chemical) and instrument methods. If monitoring over an extended period is specified, then an instrument technique is usu
24、ally re- quired, and in some compliance testing, manual methods are specified. In most other cases, either method can be used and the choice must be made on the basis of accuracy, convenience, and practicality. In general, instrument methods will be more convenient when many readings are required. I
25、nstrumental methods are more expensive and require relatively complicated sample conditioning and calibrating systems. Manual methods often require only simple apparatus and are inexpensive, but may en- tail a considerable delay in obtaining results. Manual methods also require careful work by an ex
26、perienced technician if accurate results are to be obtained. Section 4 on the specific gas analysis should be referenced for selection of a suitable analytical technique. 3.02.3 Test Plan 3.02.3.1 Before the test is started, a detailed test plan should be prepared. This should include shakedown of t
27、he instrumentation and sampling system, the calibration procedures and frequency, the number of test runs to be made at each nominally identical condition, and the calcu- lation procedures to be used to convert the raw readings to useful form. The test plan will be influenced by the purpose of the t
28、est, the accuracy required, the stability of the combustion process, the exhaust conditions, and the analysis method used. 3.02.3.2 Attention must be given to the method to be used for extracting the sample from the exhaust stream. Since only a very small part of the total flow will be ana- lyzed, i
29、t is essential that the gas analyzed is representative of the average exhaust gas. Factors which will influence the accuracy (i.e., the validity) of the sampling system are the design of the sampling probe and the uniformity of the gas composition, velocity and temperature over the duct cross sectio
30、n at the sampling point. 3.02.3.3 Unless prior experience indicates that there is no stratification at the sampling position, it will be neces- sary to do preliminary testing to measure the velocity, temperature and composition profiles across the sample plane. A sampling procedure can then be selec
31、ted to give the required accuracy. If the stack has significant stratifica- tion that would cause large errors with single point Sam- pling, it may be necessary to traverse the stack and take samples at many points. In some cases, it is possible to design a multi-hole probe that will give acceptable
32、 accu- racy (see Par. 6.06). If there is little stratification, a single reading from a single-hole probe may be adequate. 3.02.3.4 The stability of the stack conditions with time must be considered before choosing the analysis method and equipment. If conditions vary appreciably, it may be necessar
33、y to average results over a period of time. Such averaging will be much easier with instrument systems than with wet chemical methods. 6 :. . . INSTRUMENTS AND A.PPARATUS 3.02.3.5 Care must be taken that variations in velocity, temperature, or composition are not caused by changes in the operating c
34、onditions occurring while the traverse is being made. A recognized characteristic of the process such as fuel flow or the air flow to fan speed ratio should be monitored during the traverse to verify stable operation. If there is any chance of conditions in the stack changing with time, the readings
35、 should be repeated until consistent results are obtained. It may be preferable to use multi-point probes rather than traversing. Otherwise, if conditions continue to change with time, consistent results (i.e., one value) will not be obtained, but an operating range must be established. 3.02.4 Sampl
36、e Location 3.02.4.1 In maiy cases, the exhaust ducting system is long, and careful consideration must be given to selecting the sample location. The following should be considered in making this selection: 3.02.4.2 In some cases, the location of the measure- ment point is determined by the purpose o
37、f the test, eg., measurement of exhaust emissions must be taken after any emission control device while combustion efficiency tests require a location closer to the point of combustion. The concentrations of several gases will vary as the exhaust passes through “scrubbers,” and will need to be consi
38、dered when designing installations for continuous monitoring. 3.02.4.3 The composition of the gas may change with distance along the exhaust system, e.g., NO in the presence of oxygen will change to NO2 and any heavy hydrocarbons may condense out of the gas stream. 3.02.4.4 If the exhaust stream is
39、cooled sufficiently for water to condense, some components, e.g., NOZ, and S02 will be dissolved out of the gas stream into the water. 3.02.4.5 Unless two or more streams are combined, the stratification of gas will be reduced as it passes through the exhaust system, thus allowing a more simple samp
40、ling system to be used. 3.02.4.6 Measurements should not be taken within three diameters of the stack exit to avoid the possibility of any ambient air being aspirated into the exhaust and becoming included in the sample. Oxygen readings across the duct should verify that the air is not being drawn i
41、n. 3.02.4.7 For continuous systems, the apparatus should be located so that it can be readily inspected and main- tained. 7 3.02.4.8 The analysis should be made in a run of straight uniform ducting so that the velocity profile is as uniform as possible. This reduces the difficulty of obtain- ing a r
42、epresentative sample. 3.02.4.9 The velocity will be acceptably uniform if the sampling plane is at least eight diameters downstream and two diameters upstream of the nearest disturbance (bend, etc.). 3.02.5 Preliminary Test to Determine Numberof Sampling Points 3.02.5. I When there is no prior knowl
43、edge of the homogeneity of the gas concentrations across the sample plane, a preliminary test is necessary to determine the number of sampling positions. 3.02.5.2 It is first necessary to divide the duct cross section into small areas such that the conditions may be assumed to be uniform across each
44、 small area. The only requirements in subdividing rectangular ducts are that each of the areas be equal and the proper size, approximately square in shape, and that the sample be extracted at the centroid of each area, as shown in Fig. 1. Sample points in circular ducts are located along diameters n
45、ormal to each other according to the equation given in Fig. 2. . 3.02.5.3 The number of sampling points required in a given duct, may be estimated from Fig. 3. For rectangular ducts, the equivalent diameter is used. Equivalent Diameter = 2 (E$ : 2:;) Traverse Positions in Rectangular Ducts I I - 0-
46、0- 0- - 0- 0- 0- 0- 0- 0- FIG. 1 0.5 ASME PERFORMANCE TEST CODES Cross Section of Circular Gas Passage NOTE: indicates location of sample point rn=R NT rn = distance from sampling point R = radius of pipe to center of pipe Na = no. of sampling points counted NT = total no. of sampling points on from
47、 center as zero A diameter FIG. 2 METHOD OF SUBDIVIDING CIRCULAR SAMPLE PLANE Duct Diameters Upstream From Flow Disturbance (Distance A) 1 .o 1.5 2.0 2.5 50 . I I I 1 I I I o I I I I I I I 2 3 4 5 6 7 8 9 10 Duct Diameters Downstream From Flow Disturbance (Distance B) FIG, 3 DUCT DIAMETERS UPSTREAM
48、FROM FLOW-DISTURBANCE (DISTANCE A) 8 ASME PTC*LS-LO 81 a 0759670 0051812 4 m INSTRUMENTS AND APPARATUS 9 3.02.5.4 Figure 3 will often lead to a conservatively high number of sampling points. This method is the most accurate approach to sampling situations where non- homogeneous flow is possible. A t
49、ypical test would measure the gas velocity, temperature, and composition at each of the sampling locations given by Figs. 2 and 3. Typical instrumentation for velocity and temperaturemeasurement would be a pitot tube and thermocouple. If there is poten- tial for reverse flow in the duct, a three dimensional probe must be used to determine the net mass flux. If significant gradients are suspected (such as due to a large boundary layer) the suspect areas of the cross section should be further sub-divided. If at all possible, these areas should be avoided. 3.02.5.5 To measure stratification
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