The variability of municipal solid waste and its relationship to the determination of the calorific value of refuse-derived fuels

281

Resources and Conseruation, 9 (1982) 281-300 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

WE VARIABILITY OF i4UidICIPALSOLID WASTEAND ITS RELATIONSHIP THE DETER~G~ATION

D.R. KIRKLIN,

OF THE

J.C. COLBERT,

CALORIFIC

VALUE OF REFUSE-DERIVED

P.H. DECKER, A.E. LEDFORD,

Chemical

Thermodynamics

National

Bureau

Division,

of Standards,

Center

TO

FUELS

R.V. RYAN, and E.S. DOGALSKI

for Chemical

Physics

D.C. 20234

(U.S.A.)

Washington,

ABSTRACT A study was carried municipal

out to examine

solid waste

Cockeysville,

a primary

moisture

content

or less.

Samples

Maryland.

through

shredder

of municipal

were collected

was determined,

A total of 40 samples

out for residual

the variability,

(ia.SW)at the Baltimore

moisture,

County

over a two-week Resource

solid waste which

the samples were reduced

furnace

of

Facility

in

had been processed

daily for two weeks.

were prepared

period,

Recovery

After the total

in particle

for measurements.

size to 2mm

Testing

ash, bomb ash, and calorific

was carried

or higher

heating

value. The ciaily variability

(i.e., excluding

36 % and 37 % for moisture l:iSWis directly (HHV3-B) which of only 4%.

related

variables

and ash, respectively.

to the moisture

has a daily variability

Statistical

analysis

bility of MSW constitutes being errors

the within

bag variability)

The combustible

and bomb-ash

free higher

(i.e., excluding

of the data suggests

70 to 30% of the overall

in sampling,

size reduction

of idSW is

fraction heating

the within

of

value

bag variability)

that the day to day varia-

variability, procedures,

with the other and measurement

techniques.

INTRODIJCTION The selection solid waste ogenity

of representative

(iGW) for standard

of HSW.

It is the opinion

are too smal1 to be representative results

of any analysis

The influence

test on gram amounts

about

induce

significant

on either

of many

is needed

changes

samples

quantities

of YSW.

Some suggest

the

size is also of concern.

that this size reduction

of heavy and light particles

0

test samples

Hence,

ASTM standard

composition,

and possibly

although

there

side of this question.

0X6-3097/82/OOOG--0000/$02.75

of the heter-

can be in doubt.

MSW to 2.0 or 0.3 mm particle

in chemical

of municipal

because

in the field that gram-size

in order to follow certain

of sample.

segregation

from large quantities tests is difficult

of multi-ton

using gram-size

of processing

Such size reduction

vertently

samples

laboratory

1982 Elsevier Scientific Publishing Company

methods

of

can inadeven bring

is no evidente

282 The above considerations

are important

in the decision

must be to be representative.

However,

information

of MSW must

the waste

on the variability stream

as comparison

(i.e.,

before

of how large a sample

such a decision

can be reached,

be known as it is encountered

hour to hour, day to day, week to week,

of the magnitude

of this variability

to estimated

in

etc.),

as wel1

errors

(random

and systematic). A study has been carried examined which

out to determine

over a two week period

at the Baltimore

is operated

by the Teledyne

National

At this facility,

the MSW samples

studied

shredder. referred

MSW which

processed

to coarse

The objective period)

fuel-2

particle

variability

in the moisture

through

of as received

and ash contents

Resource

the primary

shredder

ferrous

metal

has received

is often as waste

separation

minima1

[l].

processing

which

wil1 be largely

wil1 not be extendable

RDF which may have a smaller

the primary

(i.e., two week

The variabilities

and therefore

Facility

Maryland.

is defined

the short-time

facilities.

Recovery

only through

This material

(RDF-2).

MSW which

of MSW which was

in Cockeysville,

were processed

is to determine

of mass burning

processed

County

Corporation

size with or without

of this study

is characteristic

highly

has been processed

to as refuse-derived

the variability

to more

ash content.

EXPERIMENTAL* Collection Table

1 shows the schedule

bags) of RDF-2 were collected on mornings

and afternoons

approximately -foot section

separation. across

The conveyor

the entire width

the one foot segment

TABLE

Day

of successive

1.

Week

1 (Jan 14-18,

M

T

W

of the samples.

off a conveyor

belt was stopped

1980)

Collection

bag weighed belt prior to the a one

'The sample was coll

no RDF.

Schedule Week 2 (Jan 21-25,

Th

F

M

T

W

Th

1980) F

Time of Sampling

PM

AM

PM

AM

PM

AM

PM

AM

PM

AM

No. of bags

2

2

2

2

2

2

2

2

2

2

*

(or

were obtained

and approximately

of tne belt was removeo.

of the belt contained

Sample

Two samples

A pair of samples

Each individual

days.

2.5 kg and was taken consecutively

usual magnetic

ected until

used for collection daily for two weeks.

Although trade names, actual sources from which samples were obtained, specific apparatus and/or its manufacturer has been identified, the National Bureau of Standards disclaims any endorsement or recommendation of use of the commercial materials or apparatus used in this scientific investigation.

233

Statistical

Study

of Baltimore

BAG 1

2.5 kg RDF.2 SAMPLE

‘SH”RED

PIECES 10 TO 15 IN DIMENSION.

County

RDFQ

RDF-2 SAMPLE WAS COLLECTED AT THE TELEDYNE NATIONAL FACILITY.

cm

DRY SAMPLE

SAMPLE WAS WEIGHED, DRIED AT 105°C; TOTAL MOISTURE DETERMINED

SAMPLE EMPTIED ONTO 6 cm MESH SCREEN.

RETAIN

PASS THRU SCREEN

SCREEN

Pi

REDUCED TO 2cm, REDUCED TO 2mm, MIXED, SPLIT

NON-MILLABLE, PART OF ASH FRACTION

Ai

Bl

DETERMINATIONS:

Fig. 1.

HHV,

RESIDUAL

MOISTURE,

AND

ASH

RDFP Sample Processing Scheme

Processing The bags were delivered placed

in a drying

the following

morning

were labelled, is described treated

daily

to the laboratory,

oven overnight to determine

#l and #2.

at 105 "C.

the total moisture

For simplicity,

below and is illustrated

identically.

weighed,

and their contents

The dried samples were reweighed content.

the processing

in the flow diagram

Bags from each day

of bag #l of a pair in Fig. 1.

Bag #2 was

284 The dry material

from #1 was passed

the weight

of two fractions:

Exceptions

were made

as if a long metal the screen.

tained

on the screen

Wiley

Similarly,

laboratory

mill.

and Zl (retained)

from the two daily

and maybe

was reduced

samples,

bag 1, and fractions

material,such

30 cm in length),

passed

material

and added

was re-

to the Pl

in size to 19 mm or less by means

reduced

quarters

screen and

were determined.

it was sub-divided

The 2 mm material

and opposite

(8 cm) mesh

if a large piece of combustible

hammer mi11 and further

and quartered,

a 3 inch

if a piece of non-millable

for the Zl fraction,

This Pl fraction

5 horsepower

Pl (passing)

to the Pl fraction

rod (say 2 cm diameter

through

fraction.

through

was mixed

combined

four sub-samples

of a

to 2 mm or less using a Model in a "vee"-blender,

4

coned

to give an Al and Bl fraction. resulted:

fractions

A2 and B2 from bag 2, each weighing

Hence,

Al and Bl from

about one kilogram.

Procedure Measurements

of residual

moisture,

furance

value were made on each of the sub-samples. in the analysis

sample)

and D3174

coal and coke using gram-size

amounts

The "furnace

procedure.

"bomb ash" was determined The calorific ASTN

standards

of material

as the residue

value which is defined

is commonly

for residual

value on a different hydroscopic of moisture,

RDF regained

is in equilibrium

which

gives

of about

2.5 each were extracted

residual

moisture,

was determined

period.

study

separately

sample were taking

40 samples,

measurements

value

of a unit quantity

to obtain

MSW samples

conditions,

experiment

and pressed

the

This quantity is the residual by two

Quantities

into pellets

value determinations.

by weighing

of fuel

the calorific

were dried,

ash" and "bomb ash."

heating

in many

The unit quantity

of RDF and was determined

so that

place

4 sub-samples

the residue

for

Bomb ash remaining

Measurements

if a physicochemical

it might

be detected

and 20 B-sub-samples process

those from the second

familiarity

B sub-samples. of the analyst

were

due to aging of the

more readily

were made on the randomized

on the randomized

due to the increased

for each day, from a two-week

of the 20 A-sub-samples

from the first day were done first, and so on.

value determination

from the atmosphere.

from the sub-samples

of

bomb.

involved

The determinations

randomized

[z].

the as received

ash, and higher

from each calorimetrie

in the combustion This

furnace

by combustion

"furnace

for

at 575 "C and the

heating

ash content

portion

(moisture

developed

heating

the higher

conditions and/or

heating

D3173

were used with the exception

with the ambient

rise to the terms

sample),

from the higher called

moisture

Ash is the non-combustible

moisture. methods

which

Although

basis.

cellulosic

moisture

methods,

ash" was determined

as the heat produced

of solid or li.quid fuel under specified can be corrected

standard

(ash in.the analysis

a modified

ashing

ash, bomb ash, and higher ASTM

than if sub-samples day were done second,

A sub-samples

In addition, with testing

followed

any systematic procedures,

by errors

preparation

of the samples, readily

operation

apparent

of the bomb calorimeter,

and the like, could be more

as a result of the randomization.

DISCUSSION OF RESULTS The results fraction

of the determinations

(non-millable

(as-determined)

value

metal

Columns

during

the sample

due to the hygroscopic

moisture

relates

to the increase

processing.

The metal

sample

Table

on a dry basis.

bomb ash (dry basis) material

listed

ash from Table

calculated

MSW.

in sample weight

2 and 3, respectively. 4 was combined

in Table

values)

for coal

Table 4 contains

in the common

material

which

the total ash content

heating

heating

of a bag.

The display

shows a variation

ture back into the RDF samples upon the constancy

of the sample period

to 49 wt. %.

HHV2 is

basis calculated heating

unit of Btu/lb. ASTM test

content,

of the total moisture

variability

observed

ash content

is obtained

data for either

in Fiqs. 7 and 8, respectively.

is

content

The absorption

reasonably

narrow

of mois-

limits and was as wel1 as the

ash values for the 10 day

fraction

ranging

from about

10

over the 10 day sampling

from 1.6 to 20.6 wt. % and is less than the

total moisture

by summing

moisture

in the laboratory,

in the non-millable

for either

variability.

within

The bomb ash and furnace

in Fig. 6; it ranges

content

of 16 wt. % (day 7, bag 2) to 52 wt. %

from 1.4 to 4.1 wt. %.

remained

ash content,

vary for each day, for each bag,

in Figs. 4 and 5, respectively,

The variation

the corresponding

values which

basis;

by using the standard

values

of the humidity

itself.

are shown

is given

total moisture

USA engineering

The data in Fig. 3, which gives the residual

of the samples,

of non-millable ash or bomb

al1 of the higher

show that the moisture

and higher

shown in Fig. 2 and shows a span of values (day 9, bag 1).

after

[3].

and for each fraction

period

to determine

3 are data on higher

bases were performed

Figs. 2-12 are histograms

sampling

The amount

the dry-ash-free

to different

pick-up

with the furnace

and HHV3 represents

and bomb ash data.

gained residual

ash (dry basis) and total

to the dry basis,

non-millable

nature

due to moisture

heating was

ash, and bomb ash are reported

5 and 6, respectively, Also

Therefore,

the as-received

(i.e., calorific

dependent

the 40 sub-samples RDF.

value

total

total moisture

bases; HHVl denotes

Calculation procedures

procedures,

furnace

heating

the sample day,

moisture,

on different

from both furnace values

Although

of cellulosic

fraction,

2, column

2, columns

were calculated

respectively.

nature

in columns

identifies

metal

ash, bomb ash, and higher

3 lists data on total furnace

in Table

of the as received

furnace

processing

moisture

ITIOiStUW.,

ash, bomb ash, and higher

7 list data on residual

fraction,

basis),

residual

The first column

2.

2 through

(non-millable)

(on an as-determined

determined

furnace

are shown in Table

bag, and fraction. moisture,

materials),

for total moisture,

or total ash content.

the quantities

of non-millable

bomb ash or furnace

The total

materials

with

ash; these data are given

The total ash variability

is comparable

to the

286

Table

Sample Day/bag

Data

Total Moist.

Metal fract.

Bomb Ash

wt. s

wt. $

wt. $

wt.

2.01 2.87 2.56 3.51

2/1A 1B 2A 2B

2.76 2.67 2.99 2.96

3/1A IB 2A 2B

2.10 2.53 1.68 2.56

4/1A 1B 2A 2B

2.16 2.17 2.92 2.50

5/1A IB 2A 2B

2.06 3.18 2.82 3:48

~/IA IB 2A 2B

2.48 2.84 1.36 2.58

7/lA IB 2A 2B

2.18 2.06 1.54 2.85

8/1A (2: (2B

1.47 2.41 1.79 2.57

9/1A IB 2A 2B

2.40 3.43 3.08 2.93

2B

Test

Resid. Moist.

l/lA IB 2A 2B

lO/lA IB 2A

2.

1.95 3.05 2.77 4.13

$

Furnace Ash wt.

%

HHV-AD MJ/kg

36.05 34.43 19.78 21.28

42.62 53.06 19.28 23.49

13.930 14.079 16.777 16.463

4.17

24.95 24.56

21.85

3.49

17.09 16.86

26.12 29.93 17.67 22.32

16.091 16.166 17.861 18.199

20.26

6.09

28.09 32.88 31.93 31.87

26.79 35.47 29.98 37.14

15.566 14.896 14.975 14.605

29.41 39.52 41.80 46.93

38.66 41.96 48.93 53.69

14.114 12.914 ll.628 10.786

14.61 20.73 17.27 17.96

16.26 22.45 16.64 19.11

17.822 16.761 17.057 16.845

31.45 44.64

34.36 40.12 34.69 35.91

14.305 12.170 14.075 14.175

33'68 .

E-05 34:17 34.83

13.996 12.530 14.442 14.172

43.20 41.41 59.38 37.47

43.49 45.90 48.46 39.97

12.660 12.767 9.053) 13.049)

23.59 27.96 24.84 32.94

23.42 28.90 26.60 33.47

15.647 14.770 15.435 14.058

9.66 9.59

10.98 10.18

17.982 17.813

;*:2 .

13.76 14.14

16.994 16.403

24.72

1.63

25.60

2.04

24.96

21.02

ll.28

17.31

13.51

17.77

7.30

38.92

3.10

44.70

3.97

26.40

12.44

27.78

8.98

24.55

14.23

16.08

20.63

20.68

7.03

21.16

3.52

52.03

4.71

23.33

2.67

25.35

3.90

22.67

4.64

;4'-:; .

36.92 44.50

287

3. Total

Table

Sample Day/bag

Total Furnace wt.

%

and

HHV-1

Ash Bomb wt.

Ash

$

Heating

Values

HHV-2

HHV-3 Furnace

MJ/kg

MJ/kg

MJ/kg

Bomb MJ/kg

l/lA IB 2A 2B

43.55 53.83 20.93 25.04

37.09 35.50 21.41 22.88

10.527 10.734 12.549 12.435

14.217 14.496 17.217 17.064

24.774 31.931 21.332 22.299

22.232 22.106 21.462 21.674

2/lA IB 2A 2B

29.20 32.86 20.54 25.03

28.03 27.70 19.98 19.77

11.goo 11.944 13.886 14.144

16.547 16.610 18.410 18.755

22.397 23.704 22.362 24.142

22.048 22.016 22.206 22.558

3/lA IB 2A 2B

31.25 39.40 37.88 44.23

32.47 36.97 39.61 39.56

11.907 ll.444 10.672 10.502

15.901 15.282 15.231 14.989

21.718 23.681 21.753 23.844

22.111 22.769 22.374 21.999

4/1A IB 2A 2B

46.94 49.80 52.66 57.07

38.94 47.69 46.05 50.81

10.318 9.441 9.130 8.432

14.426 13.200 11.977 11.062

23.516 22.741 23.453 23.888

20.434 21.827 20.580 20.846

5/lA IB 2A 2B

18.85 24.86 19.95 22.33

17.26 23.18 20.55 21.22

10.769 10.246 9.320 9.267

18.196 17.312 17.552 17.452

21.729 22.325 21.055 21.576

21.311 21.839 21.215 21.274

611~ 2A 2B

42.53 47.57 40.56 41.66

39.98 51.53 41.72 39.99

9.453 8.071 9.381 9.565

14.668 12.526 14.268 14.549

22.348 20.918 21.848 21.702

21.399 22.627 22.283 22.067

7/lA IB 2A 2B

48.15 50.31 47.75 48.28

45.89 52.40 47.08 47.36

9.260 8.278 9.769 9.716

14.307 12.793 14.668 14.589

23.669 22.081 22.281 22.385

22.679 23.053 21.999 21.997

8/1A (2: (2B

47.46 49.71 50.27 42.08

47.19 45.53 60.81 39.69

9.476 9.648 7.011 10.188

12.849 13.084 9.218 13.393

22.739 24.183 17.885 22.309

22.620 22.330 22.695) 21.420)

9/1A IB 2A 2B

27.03 32.25 28.56 35.25

27.18 31.35 26.84 34.73

7.329 6.992 11.884 10.807

16.031 15.296 15.926 14.484

20.934 21.513 21.697 21.769

20.981 21.232 21.188 21.597

lO/lA IB 2A 2B

14.46 13.68 17.76 18.13

13.18 13.12 14.10 14.00

13.156 13.179 12.888 12.616

18.341 18.373 17.478 17.110

20.604 20.453 20.266

20.301 20.322 19.403 18.971

IB

19.929

288

Table

Sample Day/bag

HHV-AD

4.

Total

HHV- 1

Heating

Values

HHV-2

HHV-3 Furnace

BTU/lb

Bomb

BTU/lb

BTU/lb

BTU/lb

BTU/lb

l/lA 1B 2A 2B

5989 6053 7213 7078

4526 4615 5395 5346

6112 6232 7402 7336

10651 I 3728 9171 9587

9558 9504 9227 9318

2/1A IB 2A 2B

6918 6950 7679 7824

5116 5135 5970 6081

7114 7141 7915 8063

9629 10191 9614 10379

9479 9465 9547 9698

3/lA IB 2A 2B

6692 6404 6438 6279

5119 4920 4588 4515

6836 6570 6548 6444

9337 10181 9352 10251

9506 9789 9619 9458

4/1A IB 2A 2B

6068 5552 4999 4637

4436 4059 3925 3625

6202 5675 5149 4756

10110 9777 10083 10270

8785 9384 8848 8962

5/1A IB 2A 2B

7662 7206 7333 7242

4630 4405 4007 3984

7823 7443 7546 7503

9342 9598 9052 9276

9162 9389 9121 9146

6/1A IB 2A 2B

6150 5232 6051 6094

4064 3470 4033 4112

6306 5385 6134 6255

9608 8993 9393 9760

9200 9728 9580 9487

7/IA IB 2A 2B

6017 5387 6209 6093

3981 3559 4200 4177

6151 5500 6306 6272

10176 9493 9579 9624

9750 9911 9458 9457

8/1A

5443 5489 3892 5610

4074 4148 3014 4380

5524 5625 3963 5758

9776 10397 7689 9591

9725 9600 9757) 9209 1

9/1A IB 2A 2B

3151 3006 5109 4646

6892 6576 6847 6227

9000 9249 9328 9359

go20

:;;07 6636 6044

lO/lA 1B 2A 2B

7731 7658 7306 7052

5656 5666 5541 5424

7885 7899 7514 7356

8858 8793 8713 8568

8728 8737 8342 8156

<:A (2B

9128 9109 9285

289 Data on the higher sampling

period

heating

are shown

in Fig. 9.

6.992 lMJ/kg (3006 Btu/lb) (day 2, bag 2, fraction

value on an as-received

The range

Fig. 10, data on the higher for the 10 day sampling (8063 Btu/lb)

ash-free

heating

basis

value on a dry basis

in two forms.

ash and bomb ash data, and are given

(HHVP) are reported are 18.755 MJ/kg

These

heating

(8568 Btu/lb) respectively,

(4710 Btu/lb).

In comparison,

respectively.

and indicate

that a closer

data and the bomb ash than the furnace as a result

of burning

The above discussion However,

included

erences

between

the RDF sample dealt

in this variability

and

positive.

The A-B differences relationship tionship

between

is important

because

standard

valent

procedures

analysis

from within

from the same bag.

plotted

versus

The diff-

has taken place between

for it is not apparent. to determine

value data.

the

This rela-

basis.

with

The existing

[4] are done on a twin or equion fraction

show the inability

Therefore,

for fur-

The A-B differ-

for both sets of ash data, the

shift

explanation

by the histograms.

A and fraction

to pick equivalent

the A-B differences

for furnace

B analysis

for HHV2 were

ash and bomb ash and are shown

Note that the furnace

ash is determined

(twin) sample and thus should show little or no correlation;

the bomb ash is determined

verify

the HHV3

B has been examined

HHV3 on a dry-ash-free

the A-B differences

in Figs. 16 and 17, respectively.

measurement

while

A systematic

sample and the above results

on an equivalent

indicated

13-15, respectively.

data and calorific

the same bag clearly

and

directly

bag variability.

A and fraction

for ash determination

samples

between

is formed

the ash values on a dry basis are combined

HHV2 on a dry basis to calculate ASTM

exists

for HHV2 and ash were also examined ash content

to

in the bomb calorimeter.

negative,

the two sets of data and a reasonable

(9911 Btu/lb)

ash since the former

in figs.

to be mostly

is mostly

corresponds

These data show a range of only 4.082 MJ/kg correspondence

is the within

the data for fraction

ence for HHV2 appears

The data

the data for HHV3 based

solely with the variability

nace ash, bomb ash, and are shown

A-B differente

to the furnace

in Figs. 11 and 12, respectively.

(8156 Btu/lb)

(1755 Btu/lb)

values on a dry-

are related

upon the bomb ash has a high and low value of 23.053 MJ/kg 18.971 HJ/kg

In

ash have a high and low value of 30.885 MJ/kg

(13278 Btu/lb) and 19.929 MJ/kg a range of 10.955 MJ/kg

(3000 Btu/lb).

In this case, the range is more

The data on the higher

(4000 Btu/lb).

for HHV3 based on the furnace

spans a range from

is over 6.978 MJ/kg

(3963 Btu/lb).

(HHV3) are given

(HHVl) for the 10 day

B) to 14.144 I/IJ/kg(6081 Btu/lb)

The high and low values

period.

and 9.218 MJ/kg

than 9.304 MJ/kg

The variability

(day 9, bag 1, fraction

B).

basis

and thus should

as the bomb residue show a definite

from the actual

correlation.

calorific

value

Figs. 16 and 17

this.

A definite bomb ash.

inverse

relationship

exists

between

the A-B differences

This is not the case for HHV2 and the furnace

ash.

for HHV2 and

A correlation

290 coefficient strong HHVZ

equal

to -0.965

relationship

indicating

During

while

is obtained

a value of -0.236

a much weaker

the course

between

and almost

of examining

bomb ash, the A-B differente

the bomb ash and HHVZ showing

is found

the experimental

obtained

between

insignificant

data for HHVZ,

for day 8, bag 2 appeared

For this reason,

omitted

16 and 17 and from al1 statistical

STATISTICAL

ANALYSIS

A statistical following

culated

the higher

(2) metal

heating

basis using furnace

on a dry ash-free

parameters

on measurements

ash and

for day 8, bag 2 were calculations.

the higher

Table

basis,

heating

ash data, and (8) HHV3-B,

The following

for each of the

(3) furnace

value on an as-received

basis using bomb ash data.

for this study.

determined fraction,

(7) HHV3-F,

value on a dry basis,

a dry and ash-free value

was performed

(1) total moisture,

(5) HHVl,

heating

the data obtained

furnace

to be significantly

OF RESULTS

analysis

properties:

(4) bomb ash, the higher

ash and

relationship.

large and atypical. from figures

the furnace

ash, (6) HHV.2,

value

the higher

value

(2) component column

shown

in column

of variability

set of statistical

heating

parameters

were cal-

2;

due to within

bag variability

shown

in

3; Table

5. Summary

of Results

Components,

Property

Average

Within ES%

expressed as r&CVfor

Bags Within days

Between m

Total(a)

- _

27.9

22.7

36.0

7.2

-_

36.8

61.3

71.5

Furnace Ash (8)

31.2

6.5

23.0

29.8

38.2

Bomb Ash ($1

28.9

10.6

15.6

33.7

38.6

HHVI

10.530

3.2

12.2

11.6

17.1

HHV2

15.393

3.2

6.6

11.2

13.4

HHV3-F

22.523

5.1

5.4

3.1

8.0

HHV3-B

21.664

1.6

1.5

3.7

4.3

Total Moisture($)

26.0

Metal Fraction($)

on

5 qives the statistical

for each set of measurements:

(1) average

a

(a) Total %CV is the sum in quadrature of the %CV for within bag, bags within days and between days.

291 (3) component column

of variability

due to within

day variability

shown

in

of variability

due to day to day variability

shown

in

4;

(4) component column

5; and

(5) the total variability The statistical as the percent S/X where average

parameters

coefficient

expressed

by items

of variation

S is the standard

deviation

solid waste culated

(5) are expressed

is defined

of an individual

of the combustible

(MSW) were derived

for the moisture

% CV is from the within HHVl was 17.1.

as % CV = (100)

measurement

bustible heating

fraction

and non-combustible

from this study.

and ash content day and between

This indicates

ture and ash content

and x

of MSW can be extracted

value on a dry and bomb ash-free be determined

efficient,

shown

from HHV3-B

the

iS

by looking basis.

to a correlation

between

The total % CV for HHV3-B

the furnace

ash.

fraction

of MSW is surprisingly

variability

accounts

for 37.21%

the A-B differences

equivalent

analysis

which

of % CV.

The % CV for due to mois-

The variability at HHV3-B which

because

of the comis the higher

fraction

was and

the correlation

co-

HHV2 and bomb ash was calculated of -0.236

betweeen

is only 4.3 which homogeneous.

HHV2 and

indicates

that the

In fact, the within

(1.6 of 4.3) of the total % CV for HHV3-B are most probably

and are a reflection samples

of 36% were cal-

The combustible

coefficient

combustible

of municipal

70 and 80 % of the total

of MSW is primarily

content.

rather than HHV3-F

in the last section,

and heavy particles,

Between

day components

that variability

components

% CV in excess

of KW.

and not to combustible

to be -0.965 compared

cludes

(2) through

(% CV) which

or mean value.

The variabilities

should

in the last column on the right.

due to segregation

of the analyst's

inability

bag

and in-

of light to choose

from the same bag.

CONCLUSIONS

(1)

Data derived

show that the within

‘value

depend about

(2)

upon the nature

out test methods

for moisture,

day and between

day variability

of the waste

70 to 80% of the overall

that improvements

attaining

within

greater

all precision

Data on the calorific manner

using the bomb ash data because

the combustion heating

calorimetrie

value on a moisture

impact upon

not increase

measurement ash-free

uncertainty.

in a more precise

the actual ash which is used to calculate

basis, HHVS-B.

the over-

manner.

about 20 to 30% of the overall

value of RDF-2 can be expressed

constitute

properties.

which

in a significant

CaiOrifiC

of refUSe are large and

in the measured

wil1 probably

properties

constitute

ash, and

These variabilities

in the test method

bag precision

of the measured

bag variability

stream.

uncertainty

Test data suggest

Within (3)

from carrying

formed

during

the higher

292

(4)

(5)

Total moisture,

metal

on a within-day

and between-day

The precision

is made to remove

measure (6)

and ash content

contributions of variability

The experimental

of the heating

The data for HHV3-B

data show large variability

basis.

of data for the higher

all coefficients pectively.

fraction,

heating

value

due to moisture for HHV3-F

data indicate

improves

The over-

and ash content.

and HHV3-B that HHV3-B

value of RDF, on a moisture

shows that the combustible

as correction

are 8.0 and 4.3%, is the most

res-

precise

and ash free basis.

fraction

of RDF is reasonably

constant. ACKNOWLEDGEMENTS This research Office

was funded

of Energy

We acknowledge Resource

by the NBS Office

from Municipal the cooperation

Recovery

in Cockeysville,

Facility

of Recycled

Materials

and the DOE

Waste.

which

and assistance is operated

provided

by the Baltimore

by the Teledyne

National

County

Corporation

Maryland.

REFERENCES ASTM Committee

[2]

ASTM Standard

D121, Definition

[3]

ASTM Standard

D3174, Ash in the Analysis

[4]

ASTM Standard

03180,

Hollander,

E38.93

Sanders

to Different

Bases.

on Terminology.

Thesaurus

Cl]

& Thomas,

Inc., Pottstown,

Calculating

of Terms

compiled

by Herbert

1.

Pa. 19464.

Relating Sample

to Coal and Coke. of Coal and Coke.

Coal and Coke Analysis

from As-Determined

293

50

2 3

% 40 ö = 30

m

s+

m

N

RDF-2

Fig.2

Variability

m

Tt

Sample

(D

10

of

Total

*

UI

b

m

UJ

DAYS

/

hl

d

Moisture

10

7 s ..-e

03 B ; d

2 1 0

m

.-l

m

N

RDF-2

Fig.

3

Variability

Sample of

(L3

10

Residual

b

/

al

DAYS Moisture

(3)

m 4

294

100 90

80 .o g 70 e 0 ô0

::

-5 50

::

f

::

40

_n 30 Fi In 20 10

0 m

8-i

m

N

RDF-2 Fig.4

100 90

Variability

*

m

Sample of

(D

ID

Bomb

m

b

cn

DAYS

/

61

4

Ash

_ ::

.Q 80 :: 5 t 70 :: c? i. 60 s .e f 50

3 (

40

8 o 30 E L 20 10

m

4

m

N

RDF-2

Fig.5

Variability

-f

Ln

Sample of

Furnace

m

r.

(D

ID

/

DAYS Ash

0)

m 4

295

30 _

ls

4

m

N

RDF-2 Fig.

6

Variability

t

UI

Sample

UI

10

b

m

a,

DAYS

/

of

Non-millable

v

In

m

s-4

Material

100 90 Q g 80

L cìf 70 2 60 ..

ö u 20 :: c

m Fig.7

s-l

N

m RDF-2

Variability

Sample of

Total

UI

10

b

/ Bomb

m DAYS Ash

a,

m -

HHVl

in MJ / ky Total Furnoce

HHVI

in

Btu

/

lb

Ash

in

Percmt.

297

24 _

_

10000

20 .. uv Y \.

2 \ 2

..6000

’ .s ..l

16 ..

ts c .e

..8000

12 .. ..4000

z P

N g

8 ..

RIJF-2 Fig.

10

Samp of

Variability

HHV2

24 _

10000

20 ..8000 5’ \ z

> io

16

s .d

12

‘fg r

8

z

..6000

.r,

..4000

L ) s

..2000

4

0

-

-

m

4

m

N

RDF-2 Fig.11

Variability

t

In

Sample of

-

I0

(D

b

10

/

HHVJ-F

m DAYS

UI

61

rl

-

.-I

f

9

l

10

i-

HHV3-B

in

Btu /

lb

299

15 _ ... rL . _r 9 :: 9 E oí= mZ --ti. c: 0. LLL: ,L,... cc" v-3 m I <

-6

::

12

-_ 1 11 J..

3 RDF-2

Fig.14

-1000 1

Fig.15

Effeot

1

2

1

4

5

6

7

SAMPLE

10

of

the

Sample

3

4

RDF-2 Effeot of

5

6

/

8

9

10

on

8omb

DAYS Split

7

~

SAMPLE 10 / DAYS the Sample Split on

HHVl

Aah

300

1000

F

A-B ? HHV2

F

F

‘*

F FFF

F F 8:::::::::::::. F UI 4 I

Pi F’,

F,F F

Correlation

of

+ v) v-8

F F-.

-1000

Fig.16

FURNACE ASH

i

Highor

Heating

Value

and

Furnace

BOMB ASH

Fig.

17

Corrrlation

of

Higher

Heating

Value

and

Bomb Aah

Ash