1、Designation: E 1757 01Standard Practice forPreparation of Biomass for Compositional Analysis1This standard is issued under the fixed designation E 1757; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a reproducible way to converthardwoods, softwoods, herbaceous materials (such as switch-grass and sericea), agricu
3、ltural residues (such as corn stover,wheat straw, and bagasse), wastepaper (such as office waste,boxboard, and newsprint), feedstocks pretreated to improvesuitability for fermentation and fermentation residues into auniform material suitable for compositional analysis.1.2 Milling and sieving actions
4、 both produce large amountsof dust. This dust can be a nuisance hazard and irritant. Useappropriate respiratory protection as needed. If excessiveamounts of dust are allowed to become airborne a potentialexplosion hazard is possible. Provide appropriate dust controlmeasures as needed.1.3 The values
5、stated in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-pr
6、iate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E11 Specification for Wire-Cloth Sieves for Testing Pur-poses3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ambient conditionsa
7、temperature of 20 to 30C (68to 85F), less than 50 % relative humidity.3.1.2 prepared biomassbiomass that has been preparedaccording to this practice.4. Significance and Use4.1 Preparation Method AMethod suitable for the prepa-ration of large quantities (20 g) of field collected samples intoa form ap
8、propriate for compositional analysis. Woody samplesmust first be available as chips of a nominal 5 by 5 by 0.6 cm(2 by 2 by14 in.) or less and twigs not exceeding 0.6 cm (14in.) diameter. Herbaceous materials may be processed as wholestraw. It is recommended that wastepaper should be shreddedinto pi
9、eces less then 1 cm (12 in.) wide. Furthermore, it isrecommended that twigs, straw and wastepaper should notexceed 61 cm (24 in.) in length to facilitate handling.4.2 Preparation Methods B and CTest methods are suit-able for very moist feedstocks, samples that would not bestable during prolonged exp
10、osure to ambient conditions, or fordrying materials when room conditions deviate from theambient conditions described in 3.1.1. These test methods arealso suitable for handling small samples of biomass (20 g)of biomass as described in 4.1.6.2 The raw biomass material should be spread out on asuitabl
11、e surface to air dry prior to any milling. Do not pile thematerial deeper then 15 cm. Turn the material at least daily toensure even drying and minimize molding of material that maycontain significant amounts of moisture. The material isconsidered dried when the change in weight is less than 1 % in2
12、4 h.6.3 The air-dried material is fed into the knife-mill and ismilled to pass througha2mmscreen in the bottom of the mill.Milled wastepaper does not need to be sieved and can be useddirectly for composition analysis. Milled biomass materialsshould be sieved as follows.6.4 The sieving is set up by s
13、tacking the sieves in thefollowing order, starting at the bottom: start with the bottompan, next stack the 80 mesh sieve, followed by the 20 meshsieve. Milled material is placed no more then 7 cm deep in the20 mesh sieve.6.5 Place the cover on the sieve stack and secure the stackin the sieve shaker.
14、6.6 The sieves need to be shaken for 15 6 1 min.At the endof the time period remove the sieves. The fraction retained onthe 20 mesh sieve (+20 mesh fraction) should be reprocessedbeginning at step 6.3. The fraction retained on the 80 meshsieve (20/+80 mesh fraction) should be retained for compo-siti
15、onal analysis. The material in the bottom pan is the fines(80 mesh). Retain this material for ash analysis.6.7 Repeat 6.3-6.6 until all of the milled material will passthrough the 20 mesh sieve. If necessary, combine all of the-20/+80 mesh batches. If necessary, combine all of -80 meshbatches. Weigh
16、 the combined 20/+80 mesh fraction and thecombined fines to the nearest 0.1 g. Record the 20/+80 meshfraction weight as Wt20/80and the fines fraction weight as Wt80.6.8 If multiple sieved samples were combined they must beuniformly blended back together into a single sample. Pour the20/+80 mesh frac
17、tion into the riffle sampler, and then recom-bine the two subdivided samples in the bottom pans backtogether. Repeat this division and recombination an additionalthree times. To correctly use the riffle sampler, the sample mustbe poured evenly onto all the riffle openings at the same time.A pan, as
18、wide as the riffle opening, should be used. Pour thesample evenly off the entire side of the pan and not from theend or the corner, nor from a container such as a jar.6.9 If the total sample needs to be subdivided into smallersamples, use the riffler at this time to divide the main sample.6.10 If th
19、e prepared sample is not analyzed immediatelyafter sieving and riffling, the sample should be stored in anair-tight container or sealable polyethylene bag and kept at20C until needed.7. Report: Preparation Method A7.1 Calculate the percent of each fraction in the original,whole biomass:fraction20/80
20、,%5 Wt20/803 100 %!/Wt20/801 Wt80! (1)where:Wt20/80= weight of 20/+80 mesh fraction, g, andWt80= weight of fines fraction, g.fraction80,%5 100 % 2 fraction20/80% (2)7.2 The mass fraction is used to weigh analytical resultswhen the two fractions differ in composition, but the results areto be reporte
21、d on the original, whole biomass.8. Procedure: Preparation Method B8.1 This test method is suitable for very wet biomass that isat risk for mold growth during drying, for wet pretreatedbiomass or fermentation residues (sludges) that might degradeif allowed to stand for prolonged periods, or for dryi
22、ng biomasswhen the prevailing conditions do not meet the ambientconditions defined in 3.1.1.8.2 Dry a suitable container to hold the biomass at 45 6 3Cfor a minimum of 3 h. Remove the container, place thecontainer in a dessicator and allow to cool to room tempera-ture. Weigh the container to the nea
23、rest 0.1 g and record thisweight as Wt.8.3 Place the biomass material into the dried container. Donot pile the material deeper than 1 cm. Weigh the container andbiomass to the nearest 0.1 g and record this weight as Wi.8.4 Place the container into a drying oven maintaining thetemperature at 45 6 3C.
24、Allow the material to dry for 36 to 48h.8.5 Remove the container and biomass from the dryingoven, place in a desiccator and allow to cool to roomtemperature. Weigh the container and biomass to the nearest0.1 g and record this weight as Wf.8.6 For small quantities (20 g, andthe intermediate model, wi
25、th 1-mm screen, is suitable for samples 20 g) containing material thatwould not pass through a 20 mesh screen, reduce the particlesize for the solids by knife-milling the entire sample and sieveaccording to 6.3-6.7.8.8 Return the milled sample to the drying oven, maintain-ing the temperature at 45 6
26、 3. Keep the sample in the dryingoven at 45 6 3C for at least 4 h . Allow the samples to coolto room temperature in a desiccator. Weigh each sample to thenearest 0.1 mg and record this mass.After weighing, return thesamples to the drying oven at 45C for 1 h, cool again in thedesiccator, and weigh ag
27、ain. Repeat this step until the mass ofthe samples varies by less than 1% from the previous weighing.9. Report: Preparation Method B9.1 Calculate the percent of the total solids obtained bydrying at 45C:%T455 Wf2 Wt!/Wi2 Wt! 3 100 % (3)where:%T45= percent total solids in sample dried at 45C,Wt= tare
28、 weight of dried container,Wi= initial weight of container and sample, andWf= final weight of container and sample.9.2 For larger milled and sieved samples calculate thepercent of each fraction in the biomass dried at 45C accordingto the equations in 7.1.9.3 The mass fraction is used to weigh analyt
29、ical resultswhen the two fractions differ in composition, but the results areto be reported on the original, whole biomass.10. Procedure: Preparation Method C10.1 This test method is suitable for very wet biomass thatis at risk for mold growth during drying, for wet pretreatedbiomass or fermentation
30、 residues (sludges) that might degradeif allowed to stand for prolonged periods, or for drying biomasswhen the prevailing conditions do not meet the ambientconditions defined in 3.1.1. This test method is also suitable tohandle materials that are heat sensitive and would degrade ifsubjected to the d
31、rying oven in Test Method B.10.2 Weigh a suitable freeze-drier container to the nearest0.1 g and record this weight as Wt.10.3 Place the biomass material into the container. For solidsamples do not fill the container more than half full. Forflowable materials, that is, fermentation residues, fill th
32、econtainer only with enough material to give a uniform coatingof 0.5 cm on the walls of the container when the sample isfrozen. Weigh the container and biomass to the nearest 0.1 gand record this weight as Wi.10.4 Place the container into a dry ice/acetone slush andslowly turn the container (10 r/mi
33、n) to freeze the material intoa uniform layer on the walls of the container.10.5 Immediately place the container on the freeze-drier andallow the material to dry until all visible traces of ice and frostare gone from the sample. Typically this takes 12 h for small(20 g) containing material thatwould
34、 not pass through a 20 mesh screen, reduce the particlesize for the solids by knife-milling the entire sample and sieveaccording to 6.3-6.7.10.9 Use this prepared sample immediately for composi-tional analysis.11. Report: Preparation Method C11.1 Calculate the percent of the total solids obtained by
35、freeze-drying:% Tfd5 Wf2 Wt!/Wi2 Wt! 3 100 % (4)where:%Tfd= percent total solids of a freeze-dried sample,Wt= tare weight of freeze-drier container,Wi= initial weight of container and sample, andWf= final weight of container and sample.11.2 For larger milled and sieved samples calculate thepercent o
36、f each fraction in the freeze-dried biomass accordingto the equations in 7.1.11.3 The mass fraction is used to weigh analytical resultswhen the two fractions differ in composition, but the results areto be reported on the original, whole biomass.12. Precision and Bias12.1 RepeatabilityDuplicate dete
37、rminations on splits ofthe gross sample, by the same operator, using the same sieves,shall duplicate the percent mass fractions within 2 % absolute.12.2 ReproducibilityNo information is available on dupli-cate determinations on splits of the gross sample by differentoperators.12.3 BiasSince there is
38、 not an appropriate standard refer-ence material, no statement about bias can be made.13. Keywords13.1 biomass; fermentation residue; hardwood; herbaceous;softwood; wastepaperE1757013ASTM International takes no position respecting the validity of any patent rights asserted in connection with any ite
39、m mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical comm
40、ittee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a m
41、eeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake 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
42、, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained 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).E1757014
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