1、Designation: D6831 11Standard Test Method forSampling and Determining Particulate Matter in Stack GasesUsing an In-Stack, Inertial Microbalance1This standard is issued under the fixed designation D6831; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e 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 test method describes the procedures for determin-ing the mass concentration of p
3、articulate matter in gaseousstreams using an automated, in-stack test method. This method,an in-situ, inertial microbalance, is based on inertial massmeasurement using a hollow tube oscillator. This method isdescribes the design of the apparatus, operating procedure, andthe quality control procedure
4、s required to obtain the levels ofprecision and accuracy stated.1.2 This method is suitable for collecting and measuringfilterable particulate matter concentrations in the ranges 0.2mg/m3and above taken in effluent ducts and stacks.1.3 This test method may be used for calibration of auto-mated monit
5、oring systems (AMS). If the emission gas containsunstable, reactive, or semi-volatile substances, the measure-ment will depend on the filtration temperature, and this method(and other in-stack methods) may be more applicable thanout-stack methods for the calibration of automated monitoringsystems.1.
6、4 This test method can be employed in sources having gastemperature up to 200C (392F) and having gas velocitiesfrom 3 to 27 m/s.1.5 This test method includes a description of equipmentand methods to be used for obtaining and analyzing samplesand a description of the procedure used for calculating th
7、eresults.1.6 This test method may also be limited from use insampling gas streams that contain fluoride, or other reactivespecies having the potential to react with or within the sampletrain.1.7 Appendix X1 provides procedures for assessment of thespatial variation in particulate matter (PM) concent
8、rationwithin the cross section of a stack or duct test location todetermine whether a particular sampling point or limitednumber of sampling points can be used to acquire representa-tive PM samples.1.8 Appendix X2 provides procedures for reducing thesampling time required to perform calibrations of
9、automatedmonitoring systems where representative PM samples can beacquired from a single sample point and certain other condi-tions are met.1.9 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.10 This standard does not purport
10、 to address 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
11、Terminology Relating to Sampling and Analysis ofAtmospheresD3154 Test Method for Average Velocity in a Duct (PitotTube Method)D3685/D3685M Test Methods for Sampling and Determi-nation of Particulate Matter in Stack GasesD3796 Practice for Calibration of Type S Pitot TubesD6331 Test Method for Determ
12、ination of Mass Concentra-tion of Particulate Matter from Stationary Sources at LowConcentrations (Manual Gravimetric Method)2.2 EPA Methods from 40 CFR Part 60, Appendix A:Method 3A Determination of Oxygen and Carbon DioxideConcentrations in Emissions from Stationary Sources(Instrumental Analyzer P
13、rocedure)Method 5 Determination of Particulate Emissions fromStationary SourcesMethod 17 Determination of Particulate Emissions fromStationary Sources (In-Situ Filtration Method)2.3 EPA Methods from 40 CFR Part 60, Appendix B:Performance Specification 11 Specifications and Test Pro-cedures for Parti
14、culate Matter Continuous EmissionMonitoring Systems at Stationary Sources1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.03 on AmbientAtmospheres and Source Emissions.Current edition approved Nov. 15, 2011. Publishe
15、d December 2011. Originallyapproved in 2002. Last previous edition approved in 2005 as D6831 - 05a. DOI:10.1520/D6831-05A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, ref
16、er to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.4 EPA Methods from 40 CFR Part 63, Appendix A:Method 301 Field Validation of Pollutant MeasurementMethods from Various Was
17、te Media3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 particulate mattersolid or liquid particles of anyshape, structure, or density (other than water) dispersed in thegas phase at flue gas temp
18、erature and pressure conditions.3.2.1.1 DiscussionIn accordance with the described testmethod, all material that may be collected by filtration underspecified conditions and that remains upstream of the filter andon the filter after drying under specified conditions are consid-ered to be particulate
19、 matter. For the purposes of this testmethod, particulate matter is defined by gas borne matter (solidor liquid) captured on or in the filter after drying and weighingin accordance with this test method.3.2.2 in-stack, inertial microbalancea mechanical oscilla-tor constructed of a hollow tube of a s
20、pecific metal alloy andfitted with a filter cartridge that is designed to oscillate at afrequency that is proportional to the mass of the hollow tubeoscillator plus the mass of its filter cartridge.3.2.3 mass transducerthe mass transducer is a principlecomponent of an in-stack inertial, microbalance
21、. The masstransducer provides the mechanical structure to support andcontain the hollow tube oscillator and to support the sampleinlet nozzle fixture, source gas temperature thermocouple, andS-type Pitot tube assembly. Refer to 6.1.1 for a detaileddescription of this component.3.2.4 articulating elb
22、owa mechanical component thatmay be integrated into the sample probe just before the endconnector attaching to the mass transducer. This elbow is usedcontrol the angle of the mass transducer relative to the sampleprobe during insertion of the probe and mass transducer intothe stack and while positio
23、ning the mass transducer inlet nozzleinto the gas stream.3.2.5 filtration temperaturethe temperature of thesampled gas immediately downstream of the filter cartridge.3.2.5.1 DiscussionThe temperature of the filter cartridgeis maintained at the desired temperature by controlling thetemperature of the
24、 mass transducer case and cap.3.2.6 sampling linethe line in the sampling plane alongwhich the sampling points are located bounded by the innerduct wall.3.2.7 sampling planethe plane normal to the centerline ofthe duct at the sampling position.3.2.8 sampling pointthe specific position on a samplingl
25、ine at which a sample is extracted.3.2.9 weighing control proceduresquality control proce-dures used for verifying the calibration constant for the hollowtube oscillator.3.2.9.1 DiscussionUnlike test methods such as D6331 orD3685/D3685M, this method does not rely on weighingsample media in a laborat
26、ory before and after a test isconducted. The method includes an integrated filter dryingmechanism to desiccate the sample collection media in-situimmediately prior to and following each test run. No physicalhandling of sample collection media takes place prior to thestart of a test run through final
27、 filter analysis for the test run.Consequently, control filters typically used to characterize theimpact of filter/sample handling and transportation are notrequired with this method.4. Summary of Test Method4.1 The in-stack, inertial microbalance method involves theuse of a filter cartridge affixed
28、 at one end of a hollow tubeoscillator that is housed in a mass transducer housing. Themass transducer is attached to the end of an integrated sampleprobe and inserted through a port into the stack or duct. Asample is withdrawn isokinetically from the gas stream anddirected through the filter cartri
29、dge attached to the end of thehollow tube oscillator. Captured particulate matter and anycaptured moisture is weighed continuously as the sample gasespass through the filter cartridge and hollow tube oscillator.Sample gases then continue through the heated probe andumbilical assemblies and into a ga
30、s conditioning/control mod-ule where the collected gas sample volume is determined. Acalibrated, orifice-based flow meter is used to measure thesample gas volume. In sources where the particulate mattercharacteristics can result in significant quantity of particulatematter to be trapped on the inlet
31、 nozzle walls during sampling,the trapped particulate matter can be recovered after samplinghas been completed using a properly sized brush to detach andrecover trapped particulate matter from the inlet walls.4.1.1 DiscussionThe ability of this mass measurementtechnique to precisely quantify the mas
32、s of the filter andcollected particulate matter by correlating mass change to ameasured frequency change of the hollow tube oscillator ispredicated on the isolation of the oscillator from externalvibration sources. To remove the potential for external vibra-tion to interfere with the measurement pro
33、cess, the masstransducer housing must be sufficiently massive so that anyenergy that it absorbs from external vibrations will result in themass transducer case oscillating at a resonant frequency that ismuch lower the hollow tube oscillator. As a result, a massivehousing will absorb any external vib
34、rations and prevent thosevibrations from affecting the resonance of the hollow tubeoscillator.4.2 The filter media typically used is PTFE coated glassfiber filter media (TX-40 or equivalent) although other filtermedia can be used if desired. The filter media is mounted in aspecially designed filter
35、cartridge housing that is designed topromote a constant face velocity through the entire surface ofthe filter. The junction of the oscillating element and the baseof the filter cartridge is designed to ensure a leak free union.4.3 The sample gases are dried using a selectively perme-able membrane dr
36、yer followed by silica gel before the samplevolume is measured. An integrated computer-controlled feed-back system is used to control the sample flow rate based onstack gas temperature, velocity and gas density measurements,or user input data, to automatically maintain isokinetic sam-pling condition
37、s.4.4 To account for source gas density (molecular weight)inputs to set the isokinetic sampling conditions, the user has theoption to use manually input data acquired using an Orsatanalyzer and moisture determination apparatus, or equivalentD6831 112methods, or data supplied by an on-board carbon di
38、oxideanalyzer, oxygen analyzer and moisture measurement system.4.5 Valid measurements can be achieved when:4.5.1 The gas stream in the duct at the sampling plane has asufficiently steady and identified velocity, a sufficient tempera-ture and pressure, and a sufficiently homogeneous composi-tion;4.5.
39、2 The flow of the gas is parallel to the centerline of theduct across the whole sampling plane;4.5.3 Sampling is carried out without disturbance of the gasstream, using a sharp edged nozzle facing into the stream;4.5.4 Isokinetic sampling conditions are maintainedthroughout the test within 610 %;4.5
40、.5 Samples are taken at a pre-selected number of statedpositions in the sampling plane to obtain a representativesample for a non-uniform distribution of particulate matter inthe duct or stack.4.5.6 The sampling train is designed and operated to avoidcondensation and to be leak free;4.5.7 Dust depos
41、its upstream of the filter are recovered ortaken into account, or both; and4.5.8 The sampling and weighing procedures include desic-cation of the filter immediately before and after each test run isconducted.5. Significance and Use5.1 The measurement of particulate matter is widely per-formed to cha
42、racterize emissions from stationary sources interms of emission concentrations and emission rates to theatmosphere for engineering and regulatory purposes.5.2 This test method provides near real-time measurementresults and is particularly well suited for use in performanceassessment and optimization
43、 of particulate matter controlsachieved by air pollution control devices or process modifica-tions (including fuel, feed, or process operational changes) andperformance assessments of particulate matter continuousemissions monitoring systems (PM CEMS)5.3 This method is well suited for measurement of
44、 particu-late matter-laden gas streams in the range of 0.2 mg/m3to 50mg/m3, especially at low concentrations.5.4 The U.S. EPA has concurred that this method has beendemonstrated to meet the Method 301 bias3and precisioncriteria for measuring particulate matter from coal fired utilityboilers when com
45、pared with EPA Method 17 and Method 5(40CFR60, Appendix A).5.5 This method can accurately measure relative particulatematter concentrations over short intervals and can be used toassess the uniformity of particulate concentrations at variouspoints on a measurement traverse within a duct or stack.6.
46、System Description6.1 Major ComponentsThe in-stack, inertial microbal-ance measurement system is comprised of five major compo-nents that are listed in the following table.Mass Transducer(see 6.1.1)An assembly that houses the sample filter andinertial microbalance. Also contains the Pitot tube assem
47、bly,stack gas temperature thermocouple, sample inlet nozzleand mass transducer heaters.Sample Probe andProbe Extensions(see 6.1.2)A heated support conduit for mass transducer, sampleand purge flow lines; electrical supplies for masstransducer and probe heaters; mass transducer electricalsignal cable
48、s; and the pivoting elbow used for positioningthe mass transducer into the source gas flow.SamplePneumatic/ElectricalUmbilical Cables(see 6.1.3)A heated, flexible tubing bundle that contains thepneumatic lines for transporting the sample and purgegases from/to the mass transducer; and the electrical
49、supply and signal cabling.Control Unit(see 6.1.4)A unit that contains sample and purge supply flowsensors and controllers; stack gas velocity pressure andtemperature transducers; sample and purge supplypressure and temperature transducers, data acquisitionand instrument control systems; sample and purge gasconditioners; heater relays; and optionally, CO2,O2andmoisture measurement systems comprising the real-timemolecular weight measurement system.Pump / Power Unit(see 6.1.5)Contains the sample vacuum and purge supply pumpsand the 24 VDC power supply transformer for the
