Calorimeter Calibration for Cellulose Waste with Microcrystalline Cellulose | Lecture notes Chemical Thermodynamics

JOURNAL

OF

RESEARCH

of the National

Bureau

of

Standards

Vol.

86,

No.6, November-December

1981

Enthalpy of Combustion of Microcrystalline Cellulose

J.C.

Colbert*,

He

Xihengt,

and

D.R.

Kirklin*

National

Bureau

of

Standards,

Washington,

DC

20234

August

14. 1981

A test substance with characteristics and properties similar to those of cellulose· based solid waste products

is

needed to calibrate calorimeters and combustors which

will

be routinely burning these materials to determine

their

calorific values precisely for use in commerce. Microcrystalline cellulose

was

found to be a good calibrant

for this purpose.

The

enthalpy of combustion of microcrystalline cellulose

~H~

at (25 0q, and its estimated

uncertainty, was determined to be -2B12.401±1.725

kllmol

based upon the sample mass.

A calculated

heat

of

wetting correction of 1.514

kl

Imol

was

applied to the combustion data.

Keywords: alternative

fue~

bomb calorimetry, cellulose, enthalpy of combustion,

refuse·derived·fue~

test

substance.

1.

Introduction

The

enthalpies

of

combustion

of

heterogeneous

feedstocks such as refuse-derived-fuel (RDF)

and

wood

wastes,

are

important

thermochemical

data

because

of

the

potential

application

of

these materials in commerce as sup-

plemental

or

alternative

fuels.

When

determining

the en-

thalpy

of

combustion

of

RDF in a conventional bomb

calorimeter

or

a newly

designed

multi-kilogram

flow

calorimeter,

it

is

desirable

to have a

"test

substance"[I]1

which

can

be used for

their

calibration which is as close to

RDF in

character

as possible.

This

test substance will per-

mit the

intercomparison

of

the thermochemical results

of

different investigators in

the

new field

of

fuels from

cellulose-based solid wastes

and

will essentially serve to con-

trol

the

chemical

part

of

the

investigation. Since there is a

large fraction

of

cellulosic materials (i.e.,

paper

products) in

municipal solid waste (MSW),

we

decided

to investigate

the

possibility

of

using

a

pure

cellulose as a test substance.

Cellulose

not

only

has

a close compositional relationship to

the

major

components

of

MSW,

but

also possesses a similar

kinship to wood species, wood wastes from the

manufacture

of

paper, bagasse from the

sugar

refining industry,

agricultural wastes,

and

some forms

of

peat. These

materials have a

potential

as

supplemental

or

alternative

fuels

just

like RDF.

tGuesl

worker

from

July

1980-February 1981, Chemistry Laboratory, National

Institute

of

Metrology, P.O. Box 2112,

Peking,

People's

Republic

of

China.

·Center

for

Chemical

Physics,

Chemical

Thermodynamics

Division

'Numbers

in

brackets

indicate

literature

references

at

the

end

of

this paper.

A

search

was carried

out

to find a suitable cellulosic test

substance. We needed a cellulose which was

high

in purity,

homogeneous, inexpensive, easy to pelletize,

and

one which

could

be

obtained

in

large

quantities. Avicef,2 a readily

available commercial cellulose, was chosen because it pos-

sesses most

of

the

requirements

for use as a

calibrant

in a

bomb calorimeter.

This

cellulose

is

very homogeneous,

99.81

percent

pure,

and

presses into a pellet very easily.

Calibration

of

the oxygen bomb calorimeter was per-

formed

using

SRM benzoic acid,

standard

sample, 39i,

which is

the

accepted primary

standard

substance for

calibrating

bomb calorimeters. Comparative calorimetric

measurements

were conducted on the cellulose sample.

These

measurements for benzoic acid and cellulose, along

with the

heat

of

wetting correction for cellulose, are

presented

in this paper.

2.

Experimental

2.1

Sample

Characterization

Avicel,

pH-lOI,

lot 1018-152,

is

a microcrystalline

cellulose, which

is

an

acid hydrolyzed derivative of a dissolv·

ing

grade

of

wood pulp. It has an average particle size

of

50

micrometers

and

a pH

of

5.5 to

7.

The

sample was

not

subjected to any further purification

but

these additional analyses were made to

further

'The

commercial sources

cited

in this

paper

are included to

adequately

de~cribe

the

experimental

procedure.

Such

identification does not

impl~·

recommendation

or

endorsement

by the National

Bureau

of

Standards.

655

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Enthalpy of Combustion of Microcrystalline Cellulose

J.C. Colbert, He Xihengt, and D.R. Kirklin

1. Introduction

2. Experimental

this reaction is 0, therefore l::..CJ; = l::..H;.

2.3 Sample Preparation

desiccator over PzOs until ready for testing.

including the sample, crucible, water, and oxygen, inJ/K_

in J/K (and the percent standard deviation, %sd).

(sdm) in J/K (and the percent standard deviation of the

A mean value of -17 340.76 ± 3.44 Jig (2 sdm) was

[3]. Their l:1U: (30°C) for wood pulp is -17 385.9 ± 18.

are l:1~30 0c) = -17337.86 ± 3.44 Jig (2 sdm). Both of

o = 15.9994, C = 12.0112, H = 1.

4. Summary and Conclusions

5. References