1、Designation: D7459 08 (Reapproved 2016)Standard Practice forCollection of Integrated Samples for the Speciation ofBiomass (Biogenic) and Fossil-Derived Carbon DioxideEmitted from Stationary Emissions Sources1This standard is issued under the fixed designation D7459; the number immediately following
2、the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice defines
3、specific procedures for the collec-tion of gas samples from stationary emission sources forsubsequent laboratory determination of the ratio of biomass(biogenic) carbon to total carbon (fossil derived carbon plusbiomass or biogenic carbon) in accordance with Test MethodsD6866.1.2 This practice applie
4、s to stationary sources that burnmunicipal solid waste or a combination of fossil fuel (forexample, coal, oil, natural gas) and biomass fuel (for example,wood, wood waste, paper, agricultural waste, biogas) inboilers, combustion turbines, incinerators, kilns, internal com-bustion engines and other c
5、ombustion devices.1.3 This practice applies to the collection of integratedsamples over periods from 1 hour to 24 hours, or longer.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address
6、 all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology
7、 Relating to Sampling and Analysis ofAtmospheresD4840 Guide for Sample Chain-of-Custody ProceduresD6866 Test Methods for Determining the Biobased Contentof Solid, Liquid, and Gaseous Samples Using Radiocar-bon Analysis2.2 Federal Standards:340 CFR 60 Appendix B, Performance Specification40 CFR 60 Ap
8、pendix A, Reference MethodUncertainties In Non-Proportional Sampling Part 75 PolicyAnd Communication Efforts, EPAContract No. EP-W-07-064, Work Assignment No. 0-8, Task No. 6 (February 15,2008 Draft)3. Terminology3.1 DefinitionsFor additional definitions of terms used inthis practice, refer to Termi
9、nology D1356 and Test MethodsD6866.3.2 Definitions of Terms Specific to This Standard:3.2.1 biomass (biogenic) CO2,nCO2recently removedfrom the atmosphere by plants, then returned to the atmosphereby combustion or biogenic decay.3.2.1.1 DiscussionBiomass CO2emitted from combustiondevices is often re
10、ferred to as “carbon-neutral CO2.”3.2.1.2 DiscussionBiomass carbon contains the isotoperadiocarbon (carbon-14) in measurable quantities. Radiocarbonis a radioactive isotope of the element carbon, carbon-14,having 8 neutrons, 6 protons, and 6 electrons making up 1 10-12natural abundance of carbon on
11、earth. It decays exponen-tially with a half-life of about 5700 years and as such is notmeasurable in fossil materials derived from petroleum, coal,natural gas, or any other source more than about 50 000 yearsold.3.2.2 constant rate sampling, nsampling conducted at afixed sampling rate.3.2.3 Fossil C
12、O2,nCO2introduced into the atmospherethrough the combustion or thermal dissociation of fossilmaterials.3.2.3.1 DiscussionFossil-derived CO2is void of radiocar-bon and consists entirely of the “stable carbon” isotopes1This practice is under the jurisdiction ofASTM Committee D22 on Air Qualityand is t
13、he direct responsibility of Subcommittee D22.03 on Ambient Atmospheresand Source Emissions.Current edition approved March 1, 2016. Published March 2016. Originallyapproved in 2008. Last previous edition approved in 2008 as D7459 08. DOI:10.1520/D7459-08R16.2For referenced ASTM standards, visit the A
14、STM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Phila
15、delphia, PA 19111-5098, http:/www.dodssp.daps.mil.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1carbon-13 (having 7 neutrons, 6 protons, and 6 electrons)making up 1.2 % natural abundance carbon on earth andcarbon-12 (having 6 neutro
16、ns, 6 protons, and 6 electrons) andmaking up 98.8 % natural abundance carbon on earth.3.2.4 proportional sampling, nsampling conducted suchthat the ratio of the sampling rate to stack gas velocity orvolumetric flow rate is constant.3.2.5 speciation, nidentification of the biomass and fossil-derived
17、CO2components within bulk air effluents.3.2.6 sub-sampling, nthe process of taking a representa-tive smaller amount of sample volume from a large bulksample volume.4. Summary of Practice4.1 Representative gas samples are collected at a constantrate from stationary emission sources into portable cont
18、ainersfor shipment to off-site analytical facilities performing TestMethods D6866 analysis.NOTE 1The complexity of the analytical method requires analysis tobe performed off-site.4.2 If the variability of stack gas velocity or CO2concentration, or both, is beyond specified limits, proportionalrate s
19、ampling may need to be used. See Section 8.NOTE 2The majority of combustion sources are such that theiroperational conditions do not vary significantly and, hence, constant ratesampling would provide representative samples. However, there are somesources, for example, peaking units, whose effluent f
20、low rate (velocity)and CO2concentrations vary considerably. In such cases, it is necessary tosample proportionally. Guidelines are given on when proportional sam-pling is necessary.5. Significance and Use5.1 Greenhouse gases are reported to be a major contributorto global warming. Since “biomass CO2
21、” emitted from com-bustion devices represents a net-zero carbon contribution to theatmosphere (that is, plants remove CO2from the atmosphereand subsequent combustion returns it), it does not contributeadditional CO2to the atmosphere. The measurement of bio-mass (biogenic) CO2allows regulators and st
22、ationary sourceowners/operators to determine the ratio of fossil-derived CO2and biomass CO2in developing control strategies and to meetfederal, state, local and regional greenhouse gas reportingrequirements.5.2 The distinction of the two types of CO2has financial,control and regulatory implications.
23、6. Apparatus6.1 ProbeTubing of sufficient length, equipped with anin-stack or out-stack filter to remove particulate matter. Theprobe may be made of any material that is inert to CO2andresistant to temperature at sampling conditions, for example,stainless steel, borosilicate glass, quartz, or polyte
24、trafluoroeth-ylene.The filter may be a plug of glass wool. Samples may alsobe taken at the exhaust of any extractive continuous emissionmonitoring system (CEMS) used for monitoring pollutant ordiluent concentrations, including both full extractive and dilu-tion sampling systems.NOTE 3Samples may be
25、collected using EPAMethod 3 in conjunctionwith applicable U.S. EPA reference test methods requiring Method 5sampling apparatus.6.2 CondenserAir-cooled, water-cooled, or other con-denser to remove excess moisture that would interfere with theoperation of the pump and flow meter. The condenser must no
26、tremove any CO2. The condenser may be omitted if themoisture concentrations are too low for condensation, forexample, after dilution CEMS.NOTE 4CO2is slightly soluble in water; its effect is estimated to beless than about 0.2 %. Acid gases (for example, SO2, HCl) reduce thesolubility of CO2to a negl
27、igible level. In addition, since the methodinvolves ratios of biomass to fossil derived CO2, any solubility (if any) ofCO2in water does not affect the results.6.3 ValveNeedle valve, or equivalent, to adjust samplingflow rate. The valve may be omitted if a pump that samples ata constant rate is used.
28、6.4 PumpLeak-free diaphragm-type pump, or equivalent,to transport sample gas to the flexible bag. It may be necessaryto install a small surge tank between the pump and rate meterto eliminate the pulsation effect of the diaphragm pump on therotameter.6.5 Rate MeterRotameter, or equivalent rate meter,
29、 ca-pable of measuring sample flow rate to within 62.0 % of theselected flow rate.6.6 Sample ContainerAir tight vessel that is compatiblewith the system design, which includes flexible bags, evacu-ated canisters such as Summa canisters, vacutainer, Tedlar bag,or syringes.6.6.1 The capacity of the sa
30、mple container must be largeenough to contain at least 2 cm3of CO2(sample containercapacity (L) %CO210 2cm3) at the end of the samplingperiod.6.6.2 If sub-samples are used for shipment to the laboratory,then determine the size of the sub-sample container such that itwill contain at least 2 cm3of pur
31、e CO2.6.7 Flow Rate IndicatorIndicator that is proportional tostack gas velocity or volumetric flow rate. The following areacceptable indicators: Type S pitot tube (velocity pressure, asmeasured by manometer, transducer, etc.); ultrasonic,scintillation, thermal or other continuous flow devices; stea
32、mrates, boiler feed water, power generation (MW), processloads, fuel rates, or other proportional effluent flow equiva-lents.NOTE 5In most combustion sources, moisture can be assumed to beconstant; however, if moisture varies by more than 610 % moisture(absolute) from the average, record hourly mois
33、ture content values todetermine the effect on the constant sample rate. Constant sampling rate isbased on the moisture content at stack conditions, while the actualsampling rate is determined on a dry basis.NOTE 6If a pitot tube is used, the determination of gas density is notneeded. The square root
34、 of the velocity pressure should be used in thecalculations.6.8 Quality Assurance/Quality Control EquipmentAs in-dicated in Section 8.7. Procedure7.1 Set up the sampling train as shown in Fig. 1 or Fig. 2.D7459 08 (2016)27.2 When using the Fig. 1 configuration, locate the tip of thesampling probe wi
35、thin or centrally located over the centroidalarea of the duct or stack cross-section or at least 1 meter infrom the duct or stack wall. When using the Fig. 2configuration, it is preferable to sample after the CO2monitorsintake. Ensure that the attachment of the CO2samplingequipment does not interfer
36、e with the normal operation of theexisting equipment by adding significant restriction or backpressure, or affecting the analyzer flow rate(s).NOTE 7When using EPA Method 3 in conjunction with EPA Method5 sampling apparatus, an integrated multipoint sample taken at eachsampling point is acceptable.7
37、.3 If the flow indicator is a pitot tube, insert the sensingportion of the pitot in an interference-free location next to theprobe, for example, attaching the pitot to the probe with thesensor tip extending at least 5.1 cm beyond the tip of the probe.7.4 Record the sample location, time and date of
38、thecommencement of collection and the operators name on thecontainer. During the sampling period, record the date andtime, the sample flow rate (including temperature andpressure), and readings from the flow rate indicator at least atthe following frequencies.7.4.1 6 hours sampling time every hour7.
39、4.2 3, 4, or 5 hours sampling time every 30 minutes7.4.3 2 hours sampling time every 20 minutes7.4.4 1 hour sampling time every 10 minutes7.5 Sample at a constant rate within 610 % of the initialreading. Record the % deviation from initial reading at eachrecording of sampling rate.7.6 Using the read
40、ings from the flow rate indicator (forexample, pressure differential, steam rate, fuel rate), calculatethe mean () and standard deviation (). If 2 / x 100 (or twotimes the relative standard deviation or 2RSD) 55 %, thecondition for constant rate sampling has been met; if not, thensampling must be co
41、nducted proportionally in accordance with7.6.1 through 7.6.3.NOTE 8The 55 % (2RSD) specification was developed based onelectric utility coal-fired units where the %CO2variation was 40 %(2RSD). Under steady state conditions, the velocity or %CO2variationsfrom municipal solid waste or agricultural was
42、te combustors are notexpected to reach these levels, that is, 55 % for velocity or 40 % for%CO2.7.6.1 Record the initial sampling flow and pitot tube pres-sure differential (or other stack flow monitoring devices or flowrate indicator), and calculate the ratio.7.6.2 Maintain this ratio throughout th
43、e sampling period towithin 610 % of the initial ratio.7.6.3 Calculate the % deviation from the initial ratio asfollows:%Deviation each sampling period! 5SSampling Period RatioInitial Ratio2 1D3100 (1)FIG. 1 Sampling Train Configuration Using a ProbeFIG. 2 Sampling Train Configuration After CEMSD7459
44、 08 (2016)37.7 At the end of the sampling period, securely close thesample container and remove it from the apparatus.7.8 Prepare the sample for shipment to the analyticallaboratory by one of the following procedures:NOTE 9The final sample must contain at least 2 cm3CO2. In somecases, several sub-sa
45、mple containers may be required for analysis. Severalsub-samples may be proportionately combined into a single samplecontainer for analysis. The source may wish to retain several back-upsamples.7.8.1 Ship the sample container as is.7.8.2 Transfer a sub-sample into a smaller container orproportionate
46、ly combine multiple sub-samples.7.9 Document sample custody to ensure sample and dataintegrity in accordance with Guide D4840.8. Quality Assurance and Quality Control8.1 Constant Sampling Rate CheckCalculate the percentdeviation from the initial sampling rate. No value shall exceed610 %. If this lim
47、it is exceeded, invalidate the sample.8.2 Stack Flow Rate VariationCalculate the average stackflow rate indicator and 2RSD (twice the standard deviationrelative to the average). The 2RSD must be less than 30 %.8.3 Leak ChecksConduct a leak check of the container asfollows:NOTE 10Since the analysis i
48、s based on a ratio of14C/12C, leakingcontainers would not invalidate the sample. However, large leaks mightpose a problem by diluting the samples to the point where there isinsufficient CO2to analyze; therefore containers indicating leaks shouldnot be used.8.3.1 Perform the leak check before (mandat
49、ory) the test.Fill the container with gas, connect a water manometer, andpressurize the container to 5 to 10 cm H20. Allow to stand for10 minutes. Any displacement in the water manometer indi-cates a leak.8.3.2 An alternative leak check method for flexible bags isto pressurize the bag to 5 to 10 cm H20 and allow to standovernight. A deflated bag indicates a leak.8.3.3 Do not use any container that indicates a leak.8.4 Rate Meter CheckThe rate meter needs no calibration.Ensure that it is clean and free flowing.9. Report9.1
