Emission of organic compounds by combustion of waste plastics involving vinyl chloride polymer

Chemosphere, Vo1125,No.12, pp 1953-1960, 1992

0045-6535/92 $5.00 + 0.00

Printed in Great Britain

Pergamon Press Ltd.

EMISSION OF ORGANIC COMPOUNDS BY COMBUSTION OF WASTE PLASTICS INVOLVING VINYL CHLORIDE POLYMER Harumitsu Hiroshi

* Gifu

NISHIKAWA

SUMIDA*

Prefectural

8-58-2

and Akio

Research

Yabuta,

** The N a t i o n a l

Gifu

KATAMI

,Yasumitsu **

,

for E n v i r o n m e n t a l

Pollution

Japan

for E n v i r o n m e n t a l

Tsukuba,

TAKAHARA

YASUHARA

Institute

500,

Institute

16-20nogawa,

,Takeo

Ibaraki

305,

Studies

Japan

(Received in Gemmny 1 September 1992; accepted 30 September 1992) ABSTRACT

Organic vinyl

compounds

chloride

The a m o u n t s organic was

emitted

polymer

were

of v o l a t i l e

compounds

controlled

hydrocarbons

investigated

aliphatic

decreased

over

when

900°C.

increased

from combustion

plastics

in a n a c t u a l

hydrocarbons

combustion

hand,

a r i s e of t h e

waste

chlorinated

temperature

the a m o u n t s

secondary

involving

incinerator.

and volatile

the s e c o n d a r y

On the o t h e r

with

of w a s t e

of

some aromatic

combustion

temperature.

INTRODUCTION

The m a n a g e m e n t of v i e w

of r e c e n t

plastics

are

necessary

of w a s t e

plastics

increase

of c o n s u m e r

treated

in the

incineration

chlorine-containing converted thermal

by c o m b u s t i o n

plastics,

to t o x i c

reaction

compounds

(I-4).

operational

condition

laboratory

experiments

reported(5-7). organic

Oki

compounds

is o n e of

treatment since

they

It is u r g e n t l y

in c o m b u s t i o n

et al.

volatile

low-molecular

hydrocarbons

In t h i s

actual

study,

incineration

the e f f e c t

of

there

are

is

involving

in some

cases

of p o l y m e r s

and

of

the o p t i m u m

plastics.

Several have

of v o l a t i l e

been

chlorinated

containing

chlorinated

the b u r n i n g

The w a s t e

to be d e s t r o y e d

few r e p o r t s

waste

a point

control

to e s t a b l i s h

materials

and

of t h e s e

1953

plastics

waste

the e m i s s i o n

from

of p l a s t i c s .

PCDFs

required these

of w a s t e

However,

or

and

issues

Carefull

are a s s u m e d

decomposition

reported

by c o m b u s t i o n

of

plastics(8).

from

of w a s t e

s u c h as P C D D s

on t h e r m a l

made

or l a n d f i l l s .

chlorinated

emitted

goods

serious

waste

concerning

organic

with

compounds

plastics.

conditions

on the

formation

1954

of various vinyl

organic

chloride

compounds

polymer

was

by c m b u s t i o n

investigated

of waste

plastics

in a m e d i u m - s c a l e

involving

waste

incinerator.

EXPERIMENTAL

Facility: paper(9). meters

The s t r u c t u r e

A size of the c o m b u s t i o n

in width

is sized chamber

at

2.6 meters

11.7 m 3 .

put into

The waste

Combustion Condition

burners

plastics

involving

to be burned.

and

in length,

combustion

the secondary

using heavy

oil.

are

35 i/h and

vinyl

chloride

A diagram

experiments

were

chamber

temperature

combustion

The design 60 i/h

polymer

were

of the c o m b u s t i o n

carried

out under

the following

conditions:

temperature

of secondary

was c o n t r o l l e d combustion

about

chamber

630°C.

was m a i n t a i n e d

B;

The c o m b u s t i o n The exit about

chamber

temperature

temperature

of s e c o n d a r y

was c o n t r o l l e d combustion

about

chamber

800°C.

was m a i n t a i n e d

920°C. kilogram

at ten m i n u t e Sampling

of waste

intervals

and A n a l y t i c a l Gas

sampling

plastics

in both

each was put

into a c o m b u s t i o n

chamber

conditions.

Procedure:

was carried

The s a m p l i n g

location

out at the location

is shown

to i n v e s t i g a t e

5

A i

i

Fig.

I

Diagram

4;wet

' 2

of waste

1;Combustion fan,

2.5

chamber

650°C.

Condition

in Fig.1.

chamber

in previous

A;

The exit

Thirty

is 4.6 meters

The s e c o n d a r y

the rotary

chamber

is d e s c r i b e d

in Fig.1.

The c o m b u s t i o n

about

chamber

high.

burner and a f t e r b u r n e r

the c o m b u s t i o n

is shown

incinerator

The c o m b u s t i o n

with

of c o m b u s t i o n

respectively.

system

and

are e q u i p p e d

capacity

of waste

chamber,

scrubber,

o

incinerator 2;secondary 5;stack,

plant. combustion

A;sampling

chamber,

location.

3;exhaust

1955

the e m i s s i o n different

of h y d r o c a r b o n s

secondary

combustion

sampl i n g

bag was a d o p t e d

volatile

chlorinated

continuously

removal

of m o i s t u r e

with a S h i m a d z u detector(FID)

after

the probes

and was

x 3-mm i.d.);

carrier

oven

rate of

using

using

were as follows: mm i.d.

carrier

oven

SPB-5

a

analyzed

ionization with

liquid

oxygen.

packed

for 2 min to 200°C

and d e t e c t i o n

with a Hitachi

with

fused

rate of 5°C/min;

bags over

on alumina

35°C hold

injection

liquid

silica

temperature,

temperature,

69.6

663 G C - F I D

oxygen.

capillary

50°C hold

injection

gas(N 2) f l o w - v e l o c i t y ,

trapping

system

for the

40 ml/min.

trapping

column,

x 0.3 pm),

an i n c r e a s i n g

cold

filtration

conditioned

sampling

I% APG-L

temperature,

gas(N 2) flow-rate,

further

cold

using and

were drawn

with a flame

column,

10°C/min;

method

h y d r o c a r b o n s ( C 2 - C 5) were

H y d r o c a r b o n s ( C 6 - C 8) were a n a l y z e d pre-treatment

was

in 5-1iter

Low m o l e c u l a r

pre-treatment

samples

at two

hydrocarbons

with a p a r t i c l e

sample

collected

The c o l l e c t i o n

Gas

equipped

were as follows:

with an i n c r e a s i n g 180°C;

compounds.

compounds

of v o l a t i l e

15A gas c h r o m a t o g r a p h ( G C )

The GC c o n d i t i o n s column(1-m

sampling

A part of this

20- to 30- min period.

organic

temperatures.

for gas

organic

through

using an air pump.

and c h l o r i n a t e

column

(30 m x 0.54

for 4 min to 150°C with

and d e t e c t i o n

cm/sec;

after

The GC c o n d i t i o n s

make-up

temperature,

200°C;

gas(N 2) flow-rate,

20 ml/min. Volatile

chlorinated

organic

compounds

663 GC with

an e l e c t r o n

capture

detector(ECD).

as follows:

column,

x 3-mm

i.d.);

200°C;

carrier

In order The exhaust each

oven

20% Squalane temperature,

to a n a l y z e

other

10 ml of hexane.

dried

on a n h y d r o u s

volume

After

blowing

below

column(30-m

x 0.25-mm

2 min to 230°C with detector,

flow-velocity,

34.2

spectrometry(MS) connected analy s i s

with

2 sec;

cm/sec.

were

mass

range,

energy,

the same as d e s c r i b e d

solution

concentrated

oven

temperature,

rate of 4°C/min; 300°C;

instrument,

with a System

capillary

injection

conditions

were

40°C hold

carrier

10 to 500; 70eV;

ionizing

pressure,

above.

speed,

current,

2xi0 -6 torr.

for

temperature,

gas(He)

of mass

JEOL DX-300

scan

was

to a small

The GC c o n d i t i o n s

silica

contained

mass

spectrometer

1510A GC and with a JEOL JMA-3500

m/z

ion-source

hexane

was used.

which

5890A GC c o n n e c t e d

The o p e r a t i n g

Packard

temperature,

analysis

in series

PTE TM 5 fused

temperature,

as follows;

ionization 200°C;

x 0.25-~m);

detector

a Hewlett

system;

temperature,

i.d.

column,

an i n c r e a s i n g

FID;

40°C.

a Hewlett-Packard

integrator;

GC/MS

the c o m b i n e d

by n i t r o g e n - s t r e a m

6000B

were

sampling,

and c a r e f u l l y

instrument,

time,

compounds,

sulfate

Instruments

column(3-m

and d e t e c t o r

two impingers

sodium

as follows:

250°C;

W AW packed

injection

were

ml/min.

organic

through

with a Hitachi

The GC c o n d i t i o n s

on c h r o m o s o r b 90°C;

gas(N 2) flow-rate,35

gas was passed

were a n a l y z e d

1.3 sec; 300 pA;

data

repetition ion-source

The GC c o n d i t i o n s

1956

RESULTS

Two d i f f e r e n t of various vinyl I.

chloride

Thirty

chamber

operational

organic

kirogram

chamber

Oxygen

concentration than

0.001%

almost

of these

2.

compounds

temperature

the lower

that

effective

material

combustion

tetrachloride

were

Table

in Fig.2

organic

to 5.

of waste

Combustion Secondary

chamber

compounds

of these

levels.

conditions

Exhaust

time

(°C)

(sec) gas

temperature of exhaust

Carbon

dioxide

Oxygen

(%)

Carbon m o n o x i d e

was

or GC/ECD

shown

in Table

combustion

aliphatic

over

These 900°C

chamber

compounds results

is

compounds.

and t e t r a c h l o r o e t h y l e n e in waste

Chloroform

and carbon

The c o n c e n t r a t i o n

for waste

found

organochlorine

of 1,1,1-

incinerator

A

Condition

180

180

624-661

774-820

654-682

905-940

chamber

of wet exhaust gas

(kg/h)

(°C)

Residence

Composition

burned

are

became.

combustion

by Oki et al.(8).

temperature

combustion

temperature

Amount

plastics

state

time on G C / F I D

Condition

Amount

The

A, less

Identification

and second

level as those

below d e t e c t a b l e

I. O p e r a t i o n a l

combustion

of q u a n t i t a t i o n

of t r i c h l o r o e t h y l e n e

reported

18 %.

in c o n d i t i o n

a complete

of secondary

as same

650°C and

in each

exceeded

of most of v o l a t i l e

decomposition

were

about

1.8 seconds

always

0.008-0.014%

Results

chlorinated

The c o n c e n t r a t i o n s in our e x p e r i m e n t

time was

of the c o m b u s t i o n

the t e m p e r a t u r e

to c o m p l e t e

of the s e c o n d a r y

shown

the c o n c e n t r a t i o n

(C2-C 8) and v o l a t i l e suggest

in Table

temperatures

out by r e t e n t i o n

on GC/MS.

involving

shown

B.

are

was carried

are

into a c o m b u s t i o n

Therefore,

in c o n d i t i o n

spectrum

The higher

were,

B.

was

the e m i s s i o n

plastics

each was put

in chamber

of carbon m o n o x i d e

gas c h r o m a t o g r a m s

and by mass

The

the r e s i d e n c e

in c o n d i t i o n

to compare

A and B were m a i n t a i n e d

concentration

accomplished

Typical

plastics

intervals.

and

used

of waste

combustion c o n d i t i o n s

Actual

in c o n d i t i o n

920°C r e s p e c t i v e l y , condition.

were

by c o m b u s t i o n

of waste

at ten m i n u t e

combustion

DISCUSSION

conditions

compounds

polymer.

AND

(%)

(%)

(Nm3/h)

(°C)

1.8

1.8

23000

23500

178-196

221 -233

gas I .4-I .7

2.4-2.6

18.6-19.2

17.9-18.2

0.008-0.01 4

<0.001

B

1957

3

4

1 [ 0

I

l

I

5

10

15

Retention

Fig.2

Typical

gas

in e x h a u s t

time

/ min

chromatogram

of a l i p h a t i c

hydrocarbons

gas.

1;Propylene,

2;iso-Butene,

3;1-But'ene,

4;n-Hexane.

2

[__ 0

F___ 5 Retention

Fig.3

Typical

gas

in e x h a u s t

l

l

10

15

time

chromatogram

/ min of a r o m a t i c

hydrocarbons

gas.

I ;Benzene, 5;o-Xylene.

2;Toluene,

3;Ethylbenzene,

4;p

& m-Xylene,

1958

3

[

J

J

0

5

I0

Retention time / min Fig.4

Typical gas chromatogram compounds

of chlorinated

organic

in exhaust gas.

1;1,1,1-Trichloroethane,

2;Trichloroethylene

3;Tetrachloroethylene.

7

0

2

L

i

i0 Retention

Fig.5

30

20 time

Typical gas chromatogram in exhaust gas. 1;Ethylbenzene, 5;Methylundecene,

i

40

/ min

of organic

2;Xylene, 6;Pentyl

compounds

3;2-Ethylhexanol, benzoate,

4;Methyldodecane,

7;Dibutyl

phthalate.

1959

Table

2

Concentrations

of organic

compounds

in exhaust

Unit;

Compound

Aliphatic

Condition

A

~g/m 3

Condition

B

hydrocarbons

Ethylene

20

<5

Propylene

<5

14

iso-Butane

95

<5

iso-Butene

60

28 250

1-Butene

360

n-Hexane

57

8

2-Methylheptane

15

<5

8

68

<5

21

Benzene

83

17

Toluene

130

240

38

85

42

84

Metyldodecane Methylundecene Aromatic

gas.

hydrocarbons

Ethylbenzene Xylene Chlorinated

organic

compounds

Chloroform Carbon

tetrachloride

I ,1,1-Trichloroethane



<0.5

<0.5

210

140

Trichloroethylene Tetrachloroethylene

82

47

170

22

Others 2-Ethylhexanol

11

43

Pentyl

28

<5

260

120

benzoate

Dibutyl

phthalate

trichloroethane

was

the most But

predominant

organic

compounds.

because

the both of the c o n c e n t r a t i o n

it does

among

not almost

these

five c h l o r i n a t e d

contribute

and the e m i s s i o n

to air p o l l u t i o n amount

are very

low level. On the other ethylbenzene temperature. hydrocarbons volatile

hand,

the amounts

and xylene This

result

is much

aliphatic

increased

lower

suggests than

hydrocarbons

of a r o m a t i c with that

hydrocarbons

the rise

the d e c o m p o s i t i o n

that of the other if the formation

such as toluene,

of s e c o n d a r y

combustion

rate of a r o m a t i c

hydrocarbons amounts

such as

of their

compounds

1960

are almost the same level, as d e s c r i b e d

in l a b o r a t o r y r e s e a r c h reports(10).

It was a s s u m e d that dibutyl phthalate,

d e t e c t e d as shown in Table 2,

o r i g i n a t e d from p l a s t i c i z e r c o n t a i n e d in various plastics burned and retained

in e m i s s i o n gas without d e c o m p o s i t i o n even in the c o m b u s t i o n

conditions m e n t i o n e d above.

Formation m e c h a n i s m of 2 - e t h y l h e x a n o l

not clear and b e n z o a t e f o r m a t i o n in the conditions

is

is r e a s o n a b l e because

benzene ring is formed in high t e m p e r a t u r e state. The c o n c e n t r a t i o n of h y d r o g e n chloride, scrubber in both conditions,

d e c r e a s e d to 3-4 mg/Nm 3 by washing with sodium

h y d r o x i d e s o l u t i o n in the scrubber. d e t e c t i o n limit

(0.01 ppm)

being 6-10 mg/Nm 3 before wet

Phosgene levels were below the

in these conditions.

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