1、Designation: E 1755 01Standard Test Method forAsh in Biomass1This standard is issued under the fixed designation E 1755; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates t
2、he year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of ash,expressed as the mass percent of residue remaining after dryoxidation (oxidation at 575 6 25C), of hard and soft woods
3、,herbaceous materials (such as switchgrass and sericea), agri-cultural residues (such as corn stover, wheat straw, andbagasse), wastepaper (such as office waste, boxboard, andnewsprint), acid and alkaline pretreated biomass, and the solidfraction of fermentation residues. All results are reportedrel
4、ative to the 105C oven-dried mass of the sample. Forparticulate wood fuels, Test Method E 1534 should be used.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
5、ibility 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:2E 1534 Test Method for Determination of Ash Content ofParticulate Wood FuelsE 1756 Test Method
6、 for the Determination of Total Solids inBiomassE 1757 Practice for Preparation of Biomass for Composi-tional Analysis3. Terminology3.1 Descriptions of Terms Specific to This Standard:3.1.1 ashthe inorganic residue left after ignition at 575625C.4. Significance and Use4.1 The ash content is an appro
7、ximate measure of themineral content and other inorganic matter in biomass.4.2 The ash content is used in conjunction with other assaysto determine the total composition of biomass samples.5. Apparatus5.1 Ashing Crucibles, 50 mL, platinum crucibles are pre-ferred, but silica or porcelain crucibles m
8、ay be used.5.2 Muffle Furnace, an electric furnace is recommended forigniting the sample. The furnace should be fitted with anindicating pyrometer or thermocouple, so that the requiredtemperature of 575 6 25C can be maintained.5.3 Analytical Balance, sensitive to 0.1 mg.5.4 Desiccator, using anhydro
9、us calcium sulfate.5.5 Drying Oven, with temperature control of 105 6 2C.6. Test Specimen6.1 Test specimens suitable for analysis by this test methodare as follows:6.1.1 Prepared biomass samples that have been preparedaccording to Practice E 1757.6.1.2 Biomass feedstocks, dried at 105C according to
10、TestMethod E 1756,6.1.3 Pretreated biomass, dried at 105C according to TestMethod E 1756, and6.1.4 The solids fraction of fermentation residues, dried at105C according to Test Method E 1756.6.2 The test specimen shall consist of approximately 0.5 to1.0 g of sample obtained in such a manner to ensure
11、 that it isrepresentative of the entire lot of material being tested.NOTE 1All samples should be ground or milled to reduce the size ofthe large pieces to less than 1 mm in diameter. The sample is then redriedat 105C prior to testing. Prepared biomass can be used in place of 105Cdried material, but
12、the mass of the material must be corrected for itsmoisture content by using Test Method E 1756, prior to calculating theash.7. Procedure7.1 Mark a pan or crucible with a unique identification usinga porcelain marker, place it in the muffle furnace at 575 625C. Remove the pan or crucible from the fur
13、nace, cool toroom temperature in a desiccator, and weigh to the nearest 0.1mg. For an aluminum pan, two hours of heating at 575 6 25Cwill be sufficient to bring the pan to constant mass. With acrucible, however, the following procedure is used: place thecrucible in the furnace at 5756 25C for 3 h. R
14、emove thecrucible and place in a desiccator. Allow the crucible to cool to1This test method is under the jurisdiction of ASTM Committee E48 onBiotechnology and is the direct responsibility of Subcommittee E48.05 on BiomassConversion.Current edition approved November 10, 2001. Published February 2002
15、.Originally published as E1755-95. Last previous edition E1755-95.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM web
16、site.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.room temperature and then weigh the crucible to the nearest0.1 mg. Record this mass. After weighing, return the crucibleto the furnace for1hat5756 25C, cool again in thedesiccator,
17、 and reweigh. Repeat this step until the mass of thecrucible varies by less than 0.3 mg from the previous weighing.Record this final mass as the crucible tare mass, mcont. Keep thepan or crucible in a desiccator until used.7.2 Weigh approximately 0.5 to 1.0 g, to the nearest 0.1 mg,of a test specime
18、n into the tared pan or crucible. If the samplebeing analyzed is a test specimen dried at 105C, the sampleshould be stored in a desiccator until use. For a 105C driedtest sample, record the mass (container plus sample mass) asthe initial mass, mod. For prepared biomass samples preppedaccording to Pr
19、actice E 1757, record the mass (container plussample mass) as the initial mass, mar.NOTE 2For prepared biomass samples, it is recommend that samplesfor moisture determination should be weighed out at the same time as thesamples for the ash determination. If this is done at a later time it canintrodu
20、ce an error in the calculation because ground biomass can rapidlygain or lose moisture when exposed to the atmosphere.7.3 Place the container and contents in the muffle furnaceand ignite at 575 6 25C for a minimum of 3 h, or until all thecarbon is eliminated. To avoid flaming, initially heat thesamp
21、le to 250C at a rate of 10 K/min and hold for 30 minbefore increasing the temperature to 575 6 25C. Avoidheating above the maximum stated temperature.NOTE 3For test specimens containing high amounts of ash (greaterthan 5 % by mass), it will be necessary to increase the time in the furnaceto overnigh
22、t to ensure complete elimination of the carbon. This ignitiontime period should not exceed 24 h.7.4 Taking care to protect the test container from strongdrafts to avoid mechanical loss of test specimen, remove thepan or crucible with its contents to a desiccator, cool to roomtemperature, weigh to th
23、e nearest 0.1 mg, and record this mass.Repeat the heating for one hour periods until the mass aftercooling is constant to within 0.3 mg. Record the final mass ofthe ash, mash, as the container plus ash mass.8. Calculation8.1 For 105C dried materials, calculate the mass percent ofash, as follows:% as
24、h 5 mash2 mcont!/mod2 mcont!# 3 100 (1)where:% ash = mass percent of ash, based on 105C oven-driedmass of the sample,mash= mass of ash and container, g,mcont= tare mass of container, g, andmod= initial mass of 105C dried sample and container,g.8.2 For a prepared biomass sample, prepped according toP
25、ractice E 1757, the following calculation may be used toreport the mass percent of ash on a 105C dried mass basis,provided that the test specimen has already been analyzed formass percent total solids at 105C using Test Method E 1756.ms5 mar2 mcont! 3 T/100 (2)where:ms= mass of moisture-free solids
26、in the prepared bio-mass sample, g,mar= initial mass of prepared biomass sample andcontainer, g,mcont= tare mass of container, g, andT = mass percent of total solids in sample, as deter-mined by Test Method E 1756.% ash 5 mash2 mcont!/ms# 3 100 (3)where:% ash = mass percent of ash, based on 105C ove
27、n-driedmass of the sample,mash= mass of ash and container, g,mcont= tare mass of container, g, andms= mass of moisture-free solids in the preparedbiomass sample, g.9. Report9.1 Report the result to two decimal places, as a masspercent of the samples 105C dried mass, and cite the basisused in the cal
28、culation.10. Precision and Bias10.1 SummaryIn comparing two single observations (Eq1 only), the difference should not exceed 10.4 % of the averageof the two observations in 95 out of 100 cases when bothobservations are taken by the same well-trained operator usingthis procedure and specimens randoml
29、y drawn from the samesample of material.3,4The true value of ash can only be definedin terms of this procedure. Within this limitation, this testmethod has no known bias.10.2 Interlaboratory Test Data5In interlaboratory testingrun in 1993, randomly drawn samples of hybrid poplar weretested in each o
30、f five different laboratories. An operator in eachlaboratory tested duplicate specimens of the sample. Thecomponents of variance for ash results expressed as coeffi-cients of variation were calculated to be:Single-operator component 2.67 % of the averageBetween-laboratory component 8.93 % of the ave
31、rageNOTE 4The square roots of the components of variance are beingreported to express the variability in the appropriate units of measurerather than as the squares of those units of measure.10.3 Critical DifferencesFor the components of variancereported in 10.2, two averages of observed values of th
32、e ashcontent should be considered significantly different at the 95 %probability level if the difference equals or exceeds the criticaldifferences given in Table 1.10.4 Confidence LimitsFor the components of variancereported in 10.2, single averages of observed values have the95 % confidence limits
33、given in Table 2.3Technical Association of the Pulp and Paper Industry (TAPPI) StandardMethods, Method T 211 om-85, Ash in Wood and Pulp, 1991.4Vinzant, T.B., Ponfick, L., Nagle, N.J., Ehrman, C.I., Reynolds, J.B., andHimmel, M.E., “SSF Comparison of Selected Woods From Southern Sawmills,”Applied Bi
34、ochemical Biotechnology, 45/46, 1994, pp. 611626.5A copy of the supporting data for the interlaboratory test is available from theEthanol Project Chemical Analysis and Testing Task, National Renewable ResearchLaboratory, 1617 Cole Boulevard, Golden, CO 80401-3393.E1755012NOTE 5The values of the crit
35、ical differences and confidence limitsshould be considered to be a general statement, particularly with respectto between-laboratory precision. Before a meaningful statement can bemade about two specific laboratories, the amount of statistical bias, if any,between them must be established, with each
36、 comparison being based onrecent data obtained on specimens taken from a lot of material of the typebeing evaluated so as to be as nearly homogenous as possible and thenrandomly assigned to each of the laboratories.10.5 BiasThis procedure for measuring ash has no biasbecause the value of ash is only
37、 defined in terms of this testmethod. Changes in ashing parameters may vary the mass ofash recovered. Prolonged heating of the ash beyond the timesspecified in 7.3 may cause the volatilization of alkali elementsand cause a lower ash content.11. Keywords11.1 agricultural residue; ash; biomass; fermen
38、tation resi-due; herbaceous; waste paper; woodASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, a
39、nd the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revis
40、ion of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you s
41、houldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be ob
42、tained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Critical Difference, Percent of Grand Average, For theConditions NotedA,BNumber of Observationsin Each AverageSingle OperatorPr
43、ecisionBetween-LaboratoryPrecision1 10.4 26.82 7.4 25.8AThe critical differences were calculated with z = 1.960.BTo convert the values of the critical differences to units of measure, multiply thecritical differences by the average of the two specific sets of data being comparedand divide by 100.TAB
44、LE 2 Width of 95 % Confidence Limits, Percent of GrandAverage, For the Conditions NotedA,BNumber of Observationsin Each AverageSingle OperatorPrecisionBetween-LaboratoryPrecision1 67.4 619.02 65.2 618.2AThe critical differences were calculated with z = 1.960.BTo convert the values of the critical differences to units of measure, multiply thecritical differences by the average of the two specific sets of data being comparedand divide by 100.E1755013
