The influence of inhibitors and promotors on the burning ofsome dropvapour hydrocarbon with different dispersion systems

J. Aerosol S¢i., Vol. 22, Suppl. I, pp. $481-$484, 1991.

0021-8502/91 $3.00+0.00 Pergamon Press plc

Printed in Great Bdtain.

The InXluence o~" IrLhibitors and Promotors on the Burning o5 Some Dropvapour Hydrocarbon wlth Di~eren~ Dispersion Systems Kopyt N.Ch. and Struchaev A.I. Odessa State University, USSR

An i n v e s t i g a t i o n great For

interest example,

products with

flame spreading

both in

for at

products

and

theory,

industry

polymers

high

pressure.

ejection

dropvapour

by their fire safety content.

into

systems

are

by t w o -

combustion

chemical

oxidizing

fuel

vapour

of

close

The

and

Thus,

quite

and

by

oil

connected

creating Such

gas

such

of

fire safety.

possible.

of

is

obtained

accidents

homogeneous

probability

system

for

are

atmosphere

are to

phase

air-

systems

mixtures

systems

with

equal

fuel

creating

highly tures:

increases in technological processes with high temperathey cause every fourth accident, while every sixth acci-

dent is connected with easy flaming and fuel liquids. Different chemical tems the

addings

Acting

as

combustion systems

present

work

A

on

large

tural

technique fuel

inhibitor or

a

process.

However,

has

been

is

the

not

an

volume

oil

equal

was

as

the

addings goal

the

particle

average

mixture

help

an

The

dispersed

volume

generator

was

created

of

40

of

size

fuel

was

dm S was

volume

was

in-

aero-

in the

fuel

in the

promoter

generator.

dispersed work

the the

aerosol

elsewhere. (the

The

the sys-

to control

such

velocity through

of

The

allow

of

with

F5.

of

of

dropvapour

they

studied.

of the fuel-air

in all " e x p e r i m e n t s

character

investigation

well as

the

the

action

properly

spreading

described

(h.f.o.)

on

hydrocarbon

promoter,

experimental

flame

atmosphere

influence with

inhibitor addings,

fluence sol.

great

in accidents

an

disperse and

have

processes

naThis

heavy exactly

70

dinS).

The mass rate of dispersion was within the range 68 kg/s < G m < 76 k g / s a n d d e p e n d e d on work p r e s s u r e a n d t e m p e r a t u r e . That f a c t considerably decreased the fuel keep the average particle size experiments. Depending on the

polydispersion and allowed us to permanent in all series of our initial overheating, the aerosol

cloud temperature remained from perature of the surroundings.

25 to 60

K higher

than

the

tem-

The dispersed fuel average both thermodynamic parameters

size could be changed by varying and the diameter of the outlet. We

changed

size

ating

the

averaged

only, remaining

(see Fig.i). The cloud have shown tion throughout bution of the

particle the

outlet

by

changing

diameter

the

fuel

constant,

Do=

overhe8

cm,

control samples from different parts of the comparative equality of the counted concentrathe whole volume with logarithmic normal distrifuel particles sizes. The initial turbulence, $481

N. CH. KOPYTand A. I. STRUCHAEV

$482

created

by

impulsive

volume

with

the

overheating particle nm]/9

dispersed

helped

sizes

was

outlet,

to

a

The

that the

uniform

lifting

spherical

such

than

to

fuel.

form

were

less

led

character

electrical soark

ned by the beginning

of

25

kV.

The

of the jet's

cloud

the

created The

time

by fuel

2(p2/

convection

time

stream and remained set to fire by high

firing

part,

of

clouds.

relaxation

fRo/g) ~'/e, thus. they easily moved with gas in the aerosol state. The fuel mixture was volume

forces,

aerosol

their

filling

place

was

its range,

determi-

and

the cloud

center location. The

initiative energy

spherical

flame

place. The

front

rections

cameras

were

mistake

15 5. For

reducing

velocity

were

on

the we

from

influence

on

to

the

those

solid particles

We

size

propilnitratum

used

to

sodium with

pro-

up

to

connecof

flame Due

the

spreto

the

uniformly

iodide powder

Iron as

di-

decrease

form

part.

re-

cameras

film shooting

distributed

<6>=25

(CHeCHaONO)

were

deformation,

jet

firing

whole

visible

the

measu-

picture

allows

the

initial

of

data

spherical

addings

the by

visible speed

cloud

addings

the whole cloud volume.

and dispersed promoter.

That

the

them

the

spread

evaluated

put

from

motion

that

we

intermixing,

with average

so

that

defined

films. The

fast

flame

this mistake jet

was

such

All necessary

perpendicular. the

were

aerosol

developed

located

measuring

Investigating

through

the

speed

change.

based

mutually

of

ted with spreading a r i s e n volume.

turbulent

through

filmed with the help of two

.%K$-I. These

ading

duration

spreading

cloud radius

by calculations

ceived

cess was

charge

spread

visible flame

ring the burnig

the

and

the

=30

Naj

inhibitor

pan

as

the

It was determined that if dispersed h.f.o, large clouds have no outside addings, the flame visible spreading velocity increases with fuel dispersion increase can considerably change thi~

too. Inhibitor and promoter addings velocity, leading to its increase or

decrease for low concentration of addings. Relerences 1. Rozlovsky, with burning

A.I. Foundations of gases and vapours.

explosion safety when operating Chemistry Publ., Moscow, 1980,

312 p., (in Russian). %'. Pchelintsev, V.A. et al.,"Evaluation of fireand explosion safety at works, using heated easy igniting liquids", ./o~.u-n. D. /. H e n d e ~ e e ~ U C h S v.XXX, 19(55, pp.(5(5 - 74, (in Russian). S. KODyt, N.Ch. et al."Combustion and evaluations of their products Comb.

nb.S, 19(58, pp.21 - 28,(in Russian).

4. Grigoriev, er~n~

of large volume dispersed fuels in free atmosphere" PAys. F [ ~

V.A.,

Experiment.

Zorin, "

Energy

V.M.

(ed.) "Founda,~ons

Publ.

Moscow,

o/

19(5(5, 560p.

Aeat

en~ne-

(in Russian).

Influence of inhibitors and promotors

$483

Table i. Visible flame velocity of h.:'.o '~ith HaJ addings with
'lisible

flame v e l o c i t y

t/max.

m/s

Inhibi tot weight ~T= 800 K

AT= 270 K

",r. ?= 28 p.m

"ra>= 42: ~m

AT= 180 K

concentration C, % V.= :' "~

I15 m l s

V.~=

81

°6

:r.~-= 65 ff.m

mls

68 m l s

V~=

~u°°

84

4-~

--" "

3'

4.5

28

7_:I

26

~.,~

~

.4

19

I0

15

o

~

8.8

8.5

10.0

7 "6

9 l ~

':'

7.2.

'2

8.7

TaCle 2. V~sible :'lame velocity of h.f.o. "with addings of CH.~Cfl2CHeONO and

'
Visible Promotor

:'lame velocity

'"m~x'

m/s

weight ST= 800 K

AT= 270 K

AT= 180 K

~r,:= 28 ~ m


= 65 ~ m

concentration C, ",:= 115 m / s

V:a =

86 m l s

V3=

68 m l s

O.5

:24

92

68

~.0

~29

95

71

2.0

~45

~'OZ

76

2.5

142

105

76

3.0

14~

104

75

$484

N. CH. KOPYT and A. I. STRUCHAEV

• .o~.

..,~r-.

!

/

/

!/./ /

O

.D O

/.

/.

O.

o~r

I1

~

!/

I/.

i/.

I/

°~I 0.09

~

,~.

/fJ':

• •

I

~. . . . .

¢

/I

Fig,1. Porticles size distribution vs o~,erheotln9

/,

I

._~00~

/1-

,~t, ,__ , , I, "~ ........ 20'.,- .. . . . .- ,tO 60i . . . . . . . . . . . . . . . . 80 radius at portic!e, m~crons

=-

270 K.

p -

T:

180 K.

,I 100

:20, .

.L

,4" /-I

r"

I ..~4 ,-''--~

""

=

so k L

,~o.E

-I

I

, t,

,~lb

I

/./.t ,.:.~! ~ 'f/q

t i L /ill ! . r

Fig.2 DePenoence o1 the visible flame spreading ~,hrough the dispersed h.f.o, without oddincjs on the overage particles radius r • - 28 microns. P - 45 microns. ~65 microns

r

L. k L

........ , .......................... 2

4

distance,

I

6

I

8 . . . . . . . . '10

meters

150 e3

E ~'

100

0

50

i

l

fi

Fig.3 Influence of promoters and i n h i b i t o r s . o n the flame spreading velocity: o - 2~ addings of p r o m o t e r s , - x - - 10~ oddings c inhibitors, • h.f.o. aerosol.

, , , i l l , ,

. i l l , l , , ,

2

, 1 1 1 1 1 = 1 1

4

~ J l , , , , , ,

6

distance,

8 .......

meters

~o