ASTM E1757-95
(Practice)Standard Practice for Preparation of Biomass for Compositional Analysis
Standard Practice for Preparation of Biomass for Compositional Analysis
SCOPE
1.1 This practice covers a reproducible way to convert hardwoods, softwoods, herbaceous materials (such as switchgrass and sericea), agricultural residues (such as corn stover, wheat straw, and bagasse), wastepaper (such as office waste, boxboard, and newsprint), feedstocks pretreated to improve suitability for fermentation and fermentation residues into a uniform material suitable for compositional analysis.
1.2 Milling and sieving actions both produce large amounts of dust. This dust can be a nuisance hazard and irritant. Use appropriate respiratory protection as needed. If excessive amounts of dust are allowed to become airborne a potential explosion hazard is possible. Provide appropriate dust control measures as needed.
1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E 1757 – 95
Standard Practice for
Preparation of Biomass for Compositional Analysis
This standard is issued under the fixed designation E 1757; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope sitional analysis. Woody samples must first be available as
chips of a nominal 5 by 5 by 0.6 cm (2 by 2 by ⁄4 in.) or less
1.1 This practice covers a reproducible way to convert
and twigs not exceeding 0.6 cm ( ⁄4 in.) diameter. Herbaceous
hardwoods, softwoods, herbaceous materials (such as switch-
materials may be processed as whole straw. It is recommended
grass and sericea), agricultural residues (such as corn stover,
that wastepaper should be shredded into pieces less then 1 cm
wheat straw, and bagasse), wastepaper (such as office waste,
( ⁄2 in.) wide. Furthermore, it is recommended that twigs, straw
boxboard, and newsprint), feedstocks pretreated to improve
and wastepaper should not exceed 61 cm (24 in.) in length to
suitability for fermentation and fermentation residues into a
facilitate handling.
uniform material suitable for compositional analysis.
4.2 Test Methods B and C—Test methods that are suitable
1.2 Milling and sieving actions both produce large amounts
for very moist feedstocks, samples that would not be stable
of dust. This dust can be a nuisance hazard and irritant. Use
during prolonged exposure to ambient conditions, or for drying
appropriate respiratory protection as needed. If excessive
materials when room conditions deviate from the ambient
amounts of dust are allowed to become airborne a potential
conditions described in 3.1.1. These test methods are also
explosion hazard is possible. Provide appropriate dust control
suitable for handling small samples of biomass (<20 g). The
measures as needed.
drying step is done in a convection oven at 45°C (Test Method
1.3 The values stated in SI units are to be regarded as the
B) or by lyophilization (Test Method C).
standard. The inch-pound units given in parentheses are for
4.3 This practice is not intended for materials that will
information only.
already pass through a 20 mesh sieve or cannot be dried by the
1.4 This standard does not purport to address all of the
described methods to a total solids content of greater then
safety concerns, if any, associated with its use. It is the
85 %, based on an oven dried weight.
responsibility of the user of this standard to establish appro-
4.4 This practice will separate the milled material into two
priate safety and health practices and determine the applica-
fractions, a −20/+80 mesh fraction and a −80 mesh fraction.
bility of regulatory limitations prior to use.
Extraneous inorganic materials will accumulate in the −80
2. Referenced Documents mesh fraction and it should be analyzed independently from the
−20/+80 mesh fraction.
2.1 ASTM Standards:
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
NOTE 1—During analysis, the very fine consistency of this fraction may
poses
cause problems in filtrating operations and should be handled appropri-
ately.
3. Terminology
4.4.1 Weighted results from the two fractions can then be
3.1 Definitions of Terms Specific to This Standard:
combined to obtain results for materials on an “as received”
3.1.1 ambient conditions—a temperature of 20 to 30°C (68
basis.
to 85°F), less than 50 % relative humidity.
3.1.2 prepared biomass—biomass that has been prepared 5. Apparatus
according to this practice to reduce the moisture content to
5.1 Balance, sensitive to 0.1 g.
below 15 %, based on an oven-dried solids weight.
5.2 Riffle Sampler with Pans—A manual sample divider that
splits the milled biomass into a number of alternate elements.
4. Significance and Use
Riffle divisions should be in the range from 6.4 mm to 12.7 mm
4.1 Test Method A—Preparation of large quantities (>20 g)
1 1
( ⁄4 to ⁄2 in.) with at least twenty-four riffle openings across the
of field collected samples into a form appropriate for compo-
top. The feed chute and riffles should have a slope of at least
60°. Three pans are needed, one to pour the sample into the
riffler, and two to collect the two subsamples.
This practice is under the jurisdiction of ASTM Committee E-48 on Biotech-
5.3 Sieve Set, No. 20 (850 μm), No. 80 (180 μm) stackable
nology and is the direct responsibility of Subcommittee E48.05 on Biomass
sieves with lid and bottom pan. Sieves and bottom pan should
Conversion.
Current edition approved Oct. 10, 1995. Published December 1995.
Annual Book of ASTM Standards, Vols 04.02 and 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1757
be 8.9 cm (3 ⁄2 in.) in height. Sieves conform to Specification evenly onto all the riffle openings at the same time. A pan, as
E11. wide as the riffle opening, should be used. Pour the sample
5.4 Sieve Shaker, provides motion in both horizontal and evenly off the entire side of the pan and not from the end or the
vertical axes. corner, nor from a container such as a jar.
5.5 Knife Mill, for grinding samples.
6.9 If the total sample needs to be subdivided into smaller
5.6 Drying Oven,456 3° (Test Method B only).
samples, use the riffler at this time to divide the main sample.
5.7 Freeze-Drier—System with vacuum chamber and pump
6.10 If the prepared sample is not analyzed immediately
capable of maintaining a pressure of <1 torr and a cold finger
after sieving and riffling, the sample should be stored in an
in the chamber capable of maintaining a temperature of −50°C
air-tight container or sealable polyethylene bag and kept at
(Test Method C only).
−20°C until needed.
6. Procedure: Test Method A
7. Report: Test Method A
6.1 This test method is suitable for larger quantities (>20 g)
7.1 Calculate the percent of each fraction in the original,
of biomass that are essentially still in a field collected state.
whole biomass:
6.2 The raw biomass material should be spread out on a
fraction ,% 5 ~Wt 3 100 %!/~Wt 1 Wt ! (1)
20/80 20/80 20/80 80
suitable surface to air dry prior to any milling. Do not pile the
material deeper then 15 cm. Turn the material at least daily to
where:
ensure even drying and minimize molding of material that may
Wt 5 weight of −20/+80 mesh fraction, g, and
20/80
contain significant amounts of moisture. The material is
Wt 5 weight of fines fraction, g.
considered dried when the change in weight is less than 1 % in
fraction ,% 5 100 % 2 fraction % (2)
80 20/80
24 h.
7.2 The mass fraction is used to weigh analytical results
6.3 The air-dried material is fed into the knife-mill and is
when the two fractions differ in composition, but the results are
milled to pass througha2mm screen in the bottom of the mill.
to be reported on the original, whole biomass.
Milled wastepaper does not need to be sieved and can be used
directly for composition analysis. Milled biomass materials
8. Procedure: Test Method B
should be sieved as follows.
6.4 The sieving is set up by stacking the sieves in the
8.1 This test method is suitable for very wet biomass that is
following order, starting at the bottom: start with the bottom
at risk for mold growth during drying, for wet pretreated
pan, next stack the 80 mesh sieve, followed by the 20 mesh
biomass or fermentation residues (sludges) that might degrade
sieve. Milled material is placed no more then 7 cm deep in the
if allowed to stand for prolonged periods, or for drying biomass
20 mesh sieve.
when the prevailing conditions do not meet the required
6.5 Place the cover on the sieve stack and secure the stack
temperature or humidity requirements defined in 3.1.1.
in the sieve shaker.
8.2 Dry a suitable container to hold the biomass at 456 3°C
6.6 The sieves need to be shaken for 15 6 1 min. At the end
for a minimum of 3 h. Remove the container and allow to cool
of the time period re
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