ASTM_E_1757_-_01_2015.pdf

Designation:E175701(Reapproved 2015)Standard Practice forPreparation of Biomass for Compositional Analysis1This standard is issued under the fixed designation E1757;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 the year of last reapproval.Asuperscript epsilon()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),agricultural 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 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 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-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E11 Specification for Woven Wire Test Sieve Cloth and TestSieves3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ambient conditionsa 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 appropriate for compositional analysis.Woody samplesmust first be available as chips of a nominal 5 by 5 by 0.6 cm(2 by 2 by14in.)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 pieces less then 1 cm(12in.)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 exposure 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,and the intermediate model,with 1-mm screen,is suitablefor samples 20 g that will not be sieved.5.6 Drying Oven,456 3(Test Method B only).5.7 Freeze-DrierSystem with vacuum chamber and pumpcapable of maintaining a pressure of 20 g)of biomass as described in 4.1.6.2 The raw biomass material should be spread out on asuitable 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%in24 h.6.3 The air-dried material is fed into the knife-mill and ismilled to pass through a 2 mm screen 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 stacking 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.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-sitional 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 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 fraction into the riffle sampler,an