1、Designation:D7569/D7569M10(Reapproved 2015)1Standard Practice forDetermination of Gas Content of CoalDirect DesorptionMethod1This standard is issued under the fixed designation D7569/D7569M;the number immediately following the designation indicates theyear of original adoption or,in the case of revi
2、sion,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEDesignation was corrected editorially in February 2015.1.Scope1.1 This practice describes methods for the direct
3、 determi-nation of the gas content of coal by desorption using samplesobtained by drill coring methods from the surface.It sets outguidelines for the equipment construction,sample preparationand testing procedure,and method of calculation.1.2 Indirect methods for the determination of the gas con-ten
4、t of coal(not covered in this practice)are based on either thegas absorption characteristics of coal under a given pressureand temperature condition or other empirical data that relatethe gas content of coal to such other parameters as coal rank,depth of cover,or gas emission rate.1.3 This practice
5、covers the following two direct methods,which vary only in the time allowed for the gas to desorb fromthe core,or sidewall core,before final crushing:1.3.1 The slow desorption method in which volumetricreadings of gas content are taken frequently(for example,every 10 to 15 min)during the first few h
6、ours,followed byhourly measurements for several hours,and then measure-ments on 24-h intervals until no or very little gas is beingdesorbed for an extended period of time.1.3.2 The fast desorption method in which after initialdesorbed gas measurements to obtain data for lost gas calcu-lations are ta
7、ken,the canister is opened and the sample istransferred to the coal crusher.The remaining gas volume ismeasured on a crushed sample.1.4 This practice is confined to the direct method using core,or sidewall core obtained from drilling.The practice can beapplied to drill cuttings samples;however,the u
8、se of cuttingsis not recommended because the results may be misleading andare difficult to compare to the results obtained from coredesorption.The interpretation of the results does not fall withinthe scope of the practice.1.5 UnitsThe values stated in either SI units or inch-pound units are to be r
9、egarded separately as the standard.Thevalues stated in each system may not be exact equivalents;therefore,each system shall be used independently of the other.Combining values from the two systems may result in noncon-formance with the standard.1.6 This standard does not purport to address all of th
10、esafety 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:2D121 Terminology of Coal and Co
11、keD167 Test Method for Apparent and True Specific Gravityand Porosity of Lump CokeD1412 Test Method for Equilibrium Moisture of Coal at 96to 97 Percent Relative Humidity and 30CD2799 Test Method for Microscopical Determination of theMaceral Composition of CoalD3172 Practice for Proximate Analysis of
12、 Coal and CokeD3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD3174 Test Method for Ash in the Analysis Sample of Coaland Coke from CoalD3176 Practice for Ultimate Analysis of Coal and CokeD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined to Different Bases
13、D3302 Test Method for Total Moisture in CoalD5192 Practice for Collection of Coal Samples from CoreE1272 Specification for Laboratory Glass Graduated Cylin-ders1This practice is under the jurisdiction of ASTM Committee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.21 on Me
14、thods ofAnalysis.Current edition approved Feb.1,2015.Published February 2015.Originallyapproved in 2010.Last previous edition approved as D756910.DOI:10.1520/D7569_D7569-10R15E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For
15、 Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.2 Australian Standard:AS 3980 Guide to the determination of gas content ofc
16、oalDirect desorption method32.3 ISO Standard:ISO 6706 Plastics laboratory wareGraduated measuringcylinders42.4 DIN Standard:DIN 12681 Plastics laboratory wareGraduated measuringcylinders53.Terminology3.1 Definitions:3.1.1 For additional definitions of terms used in thispractice,refer to Terminology D121.3.1.2 absolute permeability,npermeability of a rock to aparticular fluid when the rock is 100%saturated with theflowing fluid.(1)63.1.3 absorbed gas,ngas that is molecularly dissolvedwithin a liq