8/10/2019 ef00045a037.pdf

1/5

788

Energy & Fuels 1994,8, 788-792

Utilization of Refinery Sludge for Lighter Oils and

Industrial Bitumen

A. P.

Kuriakose* and

S.

Kochu Baby Manjoorant

De pa r t me n t of Polym er Science and R ubber Technology, Cochin University of Science and

Technology, Kochi

682 022

Ind i a

Received Novem ber

24 1993.

Revised M anuscr ip t Received February

28 1994

This paper reports the data obtained in an at tempt to ut i l ize the waste sludge of the Cochin

Refineries Ltd., Kochi, India. Abo ut 1 7% of a lighter oil fraction can be recovered from this sludge

and t he characterist ics of th e l ighter oil are such t ha t i t can be used as diesel fuel by blending with

other appro priate refinery streams. An at tem pt was also made

to

convert the residue left after the

removal of the lighter oils into different grades of indus trial bitumen. Th is residue, obtained after

vacuum dist i lla t ion, was heat t reate d without an d with different catalysts . Th e change in softening

point:penetration ratio when heat treated w ithout any catalyst was not enough to meet t he specificat ions

of any ind ustria l bitum en. Catalys ts like sulfur, FeC13, an d

P205

were able

to

bring down the penetration

sharply bu t fa i led to increase the softening point which is a requ irem ent for the different grades of

industria l bi tume n. AlC13 was found to bring abo ut the different react ions required in the vacuum

residue and conver ted it into som e useful grades of industr ial bitumen , viz., 65125,75130,85125,a nd

901 15. Possible reaction mechanism involved is also postulated. T he optim um con ditions of

temp erature , heat ing durat ion, an d am ount of catalyst required for these different grades was

determined.

Introduction

In petroleum refineries, a lot of sludge accumulates at

the bottom of tank s where crude oil is stored. Th is is

taken out during periodic tank cleaning and dumped

separately in ponds. Also, th e bottom port ion left behind

in furnace oil tanks, LS HS (low sulfur heavy stock) tanks,

aspha lt tanks, e tc . is a lso taken ou t a t th e t ime of their

periodic c leaning and dumped in the above-mentioned

ponds. Whatever heavy oil spillages occur dur ing th e

operation of this petroleum refinery is also dumped into

th e ponds. Abo ut 8000-10000 tonnes of oily sludge is

accumu lated in the q uarry po nd of Cochin Refineries Ltd.

a t Am balamugal in Kerala , India . Th is sludge is an

accumu lat ion from th e last 20 years and has been exposed

to the atmosph ere in a l l seasons. It is l ikely to increase

further by 500-1000 tonnes per annum.

A study of the constituents of this sludge has shown

th at i t contains approxim ately 25 9 water, 5

%

inorganic

solids, and abou t 70 % hydrocarbons. Th e hydrocarb on

part is reported t o contain 7.8 w t % of aspha ltenes and

has a gross calorific value of ab out 10 300 kcallkg. T he

ash con tent is 4.8% and percentage weight of th e different

elem ents in th e as h is Fe 23.49; A1 10.57; Ca 1.64; Na 0.57;

K 0 .4 6 ; Ni 0.12; V 0 .2 3 ; Mg 0.65; Zn 0.21; Ti 0 .5 3 ; a nd Mn

0.10, Th e different methods for th e disposal of the sludge

considered are 1) burning in a rotary incinerator,

(2)

burning in a st ep furnace ty pe incinerator, (3) microbial

t rea tmen t to convert the hydrocarbons to combustible

gases, (4) using in a delayed co ker, and (5) separation of

water and sediments a t e levated temperature using

diluents and emulsifiers and subse quen t burning.

*

Author to whom correspondence should be addressed.

t Address for communication: Dept. of Quality Control, Cochin

1)Report on sludge disposal a t Cochin Refinery. Indian Oil

Refineries Ltd., K ochi, India.

Corporation R&D Report, May 1988, No. 88042.

Abstract published in Advance ACS Abstracts, April 1, 1994.

The above methods help mainly by disposing

of

t he

sludge an d no t by effective utilization. So i t was though t

worthwhile to see whether thi s sludge can be utilized as

a source of l ight oi ls and industria l bi tumen. Th e raw

materials used a t present for industria l bi tumen are

somew hat costly. Ind ustrial bitum en of various grades

are man ufactu red in India2 from th e vacuum residue of

some impo rted crudes l ike Arab m ixed, Suez Blend, e tc .

by air blowing in the presence of catalysts a t temp erature s

of 200-275

O C .

I t has been shown3 tha t dehydrogena t ion

and polymerizat ion are involved in air blowing and th at

only a minor amo unt of oxygen is added to the asphalt .

It is a lso reported t ha t naph thene aromatics are converted

i n to po la r a romat ic s a nd t he n t o a ~ p ha l t e n e s . ~ he

following are reported to be th e reactions occurring during

air blowing of th e raw m aterial.5

R H

+

0,

- HOO

R RH

-

RH

(RH = unsa tura ted compound)

RRH RH

-

disproportionation

RRHRH stable produ cts

As a result of the comparatively low concentration of

hydrocarbon radicals, there is small probability of their

recombination (2R - -R) and the interact ion of the

radicals with oxygen takes place to a smaller extent as

follows:

(2) Joseph Francis, D.; Antony, T. P. Ind. J. Technol. 1988,26,579-

3 ) Corbett, L. W.; Swarbrick, R. E. Proc. Assoc. Asphalt Pauing

4 )Rossi, Albert0 Man ufacture of blown asphalts-their physical a nd

5)Antony, T. P. Ph.D. Thesis, Cochin University of Science and

582.

Technol. 1960,

29 104.

chemical variations. Bol. Inform. Petr . Buenos Aires) 1942,19, 37.

Technology, 1989.

0887-0624/94/2508-0788 04.50/0

1994

American Chem ical Society

8/10/2019 ef00045a037.pdf

2/5

Utilization of Refinery Sludge for Lighter Oils

Energy & Fuels,

Vol

8 , N o .

3 1994

789

Table 1: Characteristics of Dehydrated Sludge and

Vacuum Rssidue of Sludge

vacuum

test dehydrated residue

characteristic method sludge of sludge

specific gravity at

27 O C

BS

2000182

1.014 1.017

softening point ( C)

IP

58/65 46 52

penetration

(1/10

m) IP

49/76 230 41

ductility (cm) IP

32/55

32.5 48

flash point ( C) IP

34/75

>200 >200

solubility in CS2

( w t

% )

B.S. 4600 99.81 99.78

loss of heating

( w t

% )

IP

45/58 0.93 0.10

R' + 0,- OO'

ROO' R'H - O O H

R'*

R O O H - O' + OH

R H *OH- ' H,O

R H HOO' - ' + H,O,

H,O,

-

'OH

R'H *OH- H,O

Various catalysts and oxidizing agents have been

proposed for augmen ting the air-blowing process of the

vacuum residue to give a product having a higher

penetr at ion for a given softening point .6 Th ey include

~ u l f u r , ~z O ~ ~n d F e c l ~ . ~ince the agents used here

cannot be recovered as such, technically they might b et ter

be termed chemical reactants than catalysts . In any event ,

the general effect is to reduce blowing tim e as well as to

change the softening point-penetrat ion relat ionship.

Reduction of blowing t ime is an economic incentive,

whereas the change in the flow propert ies permits the

manufa cture to specificat ions. In his studies, Gru nder-

m a n d o has shown tha t metal chlorides act as catalysts a t

relatively low temperatures and without air blowing,

causing condensation and polymerization reactions similar

to those obtaine d in air blowing. He ha s shown tha t t he

best c atalyst is AlC13 which converted n aphthenic arom atic

aspha l t s by t rea tmen t a t 150 C for

3

h into asp halts of

medium to high hardness.

In view of the fact th at th e refinery sludge mentioned

earl ier contains many useful hydrocarbons and that i t

accumulates in large quanti t ies in the refinery creat ing a

disposal problem, i t was thou ght w orthwhile to stu dy the

possibility of converting thi s sludge into some useful raw

material l ike industria l bi tumen w ithout th e air-blowing

process. In the present study, an at tem pt was also made

to separate the l ighter oi l fract ions from the sludge,

characterize them, and see whether they can be blended

with appro priate refinery streams. Keeping this view in

mind, the sludge obtained was first purified and dehy-

drated. Th is was then subjected to vacuum dist i lla t ion to

separate the l ight oi ls . About 1 7 % of the dehydra ted

sludge was recovered as light oil. T he residue left was

treated with varying amou nts of catalysts like sulfur eCl3,

P2O5, and a t different temp eratures ranging from

200 to 275 C, for time periods varying from

1

o

3 h.

T h e

products obtained were tested for different parameters

and th e results compared with differen t grades of industrial

bi tumen.

Experimental Procedure

Sludge was collected from the q uarry pond of Cochin Refineries

Ltd., A mbalamugal, Kerala, India. Sulfu r, FeC13, P& ,, AlC13

(anhydrous),and carbon disulfide used in the study were all of

6)Hoiberg,A. J. Catalysts for use in blowing asphalts.

R o c . Assoc.

(7)

Brooks,

B.

T.The oxidation ofmineral oils

by

air.

Ind.

Eng. Chem.

8 )Shearon,W. H. Catalytic asphalt-PhosphorousPentoxide sphalts.

(9) ampton, W.

H. S

Patent,

August 16 (1949), o. 2479235.

10)Crundermann, ErichDeut. Akad. Wiss.Leipzig ,GerErdoel Kohle

Asphalt Paving Technol. 1950,19,

225.

1917,9,

746.

Ind.Eng. Chem. 1953,45, 2122.

1965, 18(10)

80-7.

kinematic viscosity IP

71/60 474 1500

at

100

C cS)

total sulfur w ) IP

61/65 3.43 2.1

Table 2 Data of Vacuum D istillation

temp on

conversionto

recovery in

temp

press. atm press.

volume

(%)

( C)

(mm)

(760

mm) O C P

5

149 0.6 347

10

193 0.9 397

15 216 0.8 430

20 235 0.8 455

25 249 0.8 414

30 270 1.75 481 (cracking

s ta r t s )

initia l boiling point

= 295

C.

L.R. g rade. To remove water, inorganic materials, etc. the sludge

(150

kg) was heat treated in a barrel of

200

L capacity fitted

inside with steam coils. I t was maintained at

110

f 10OC for

12

h a t which time th e sludge was fully dehyd rated (tested as per

IP 291173). The remaining hot oil was then passed through

strainers (60 nd

40

mesh) to remove solid impurities. Th e oil

thus obtained was highly viscous and solid at room tem perature.

Its characteristics are given in Tab le 1. A 163-g ample of this

dehydrated sludge was taken in a round-bottomed flask and

subjected tovacuum distillation. Hot water was circulated round

the condenser and the receiver

so

th at the waxy distillate coming

out as vapour did not stick to the sides of the condenser. Th e

lighter oil fraction thus recovered from th e sludge amounts

to

17%

(see Table

2

or data of vacuum distillation). Th e residue

obtained after vacuum distillation was tested for different

parameters. These results are also given in Table 1.

According to Bureau of Indian Stan dard s (IS

702-1961)

here

are 10 different grades of indu strial bitumen depending upon

the softening point-penetration relationship. They are

65/25,

75/15, 5/30, 5/25, 5/40, 0115, 105120, 115115, 135110,

nd

15516. The first figure represents the softening point and the

second one penetration. A grade

65/25

hould have the softening

point between

59.5

and

70.5

and p enetration between

21

and

29.

Attemp ts to convert the vacuum residue of the sludge

to

some

of th e above grades of indus trial bitumen were carried out as

follows.

A 250-g portion of this vacuum residue was heated without

any catalyst in a cylindrical can (16.5 m height and 9 cm dia)

a t

250

C for

3

h with periodical stirring. Th e sample

was

hen

taken out an d tested for the different parameters (Table

3).

The

above experiment was repea ted adding 2

5

each of sulfu r, FeCls,

Pz05 nd AlC13. From th e results (T able 3) it is seen t ha t AlC13

can bring about appreciable variation in the softening point-

penetration ratio w hile the other catalysts used were not able to

bring about such a significant variation. To determ ine the

optimu m concentration of AlC13 an d the optimum time and

temperature required, the experim entwas furthe r repeated w ith

different percentages of AlCb ranging from 1 o 2.75% and

temperatures ranging from

200

o

275

OC for periods varying

from

1-3

h (see Figures

1-4).

The samples were taken out at

definite intervals and tested.

Th e softening point reported in this paper was determined by

the ring a nd ball method according to IP

58/65.

Here a steel ball

8/10/2019 ef00045a037.pdf

3/5

790

Energy &

Fuels,

Vol 8

N o . 3

994

Kuriakose and Manjooran

Table 3 Data on Heat Treatment of Vacuum Residue at 250 OC without and with D ifferent C atalysts for 3 h

catalyst specific softening penetration ductility flash matter soluble in loss on

( 2 % ) gravity point O C ) (1/10 mm)

(cm)

point

O C )

carbon disulfide (wt

% )

heating

(wt

% )

Nil

1.020 55.0 31 20.5

Sulfur

1.028 58.5 23 13.0

FeC13

1.024 58.0 26 17.5

P2O6 1.021

56.0 29 19.0

AlC13

1.030 83.0 20 5.0

>300 99.76

>300 99.70

>

300 99.72

>300 99.74

>300 99.64

0.07

0.05

0.05

0.06

0.04

1 %

AlCg

A 2.5%AIC13

A 275%AlC13

e ~ * / . A I c I ~

20 25 30

PENETRATION, 1 lOmm

Figure 1. Effect of different percentages of aluminum ch loride

on prope rties of vacuum residue of sludge.

(9.5 mm diam eter) of specified weight (3.5 g) is placed upon a

disk of sample contained within a metal ring of depth 6.4 mm;

inside diameter a t bottom and top 15.9and 17.5mm, respectively,

and outside diameter 20.6 mm. The assembly is heated at a

constant rate and the softening point is taken as the tem perature

at which the sample becomes soft enough to allow the ball

enveloped in bitumen to fall th e specified distance (25 mm). To

determine softening point below 80

O C ,

a water bath was used

for heating while for those above 80

O C

a glycerine bath was used.

Penetration was determined as per IP

49/76.

A penetrometer

made by P recision Scientific

Co.,

USA, was used for the purpose.

The experiment was conducted a t 25 O C or 5 swith a tot al moving

weight of

100

g. Th e distance in tenths of a millimeter tha t a

standard needle 50 mm long and

1.02

mm diameter) vertically

penetrates the sample is reported as penetration.

Duc tility was determined as per IP

32/55

a t

27

C and at a rate

of pull of 50 mm/min. A ductility meter manufactured by

Hum boldt Manufacturing

Co., U.S.A. ,

was used. Th e density of

water in the bath was adjusted by add ing sodium chloride so tha t

the bitumenous thread formed during the test did not touch the

bottom of the bath a t any time during the test. The distance in

centimeters by w hich a standard briqu et having the following

dimensions can be elongated before the thread breaks is reported

as ductility (total length =

75

mm, distance between clips =

30

mm, width at mouth of clip =

20

mm; and width a t minimum

cross section = 10 mm). Flash point was determined by the

Pensky-Martens closed method as per IP

34/75,

at a heating

rate of

5

C/min and with a stirrer speed of

60

rpm. The

temperature a t which the vapor above the sample can ignite with

2030c

e

225'C

9

A 2 50*C

A 275'C

20 25 30

5

PENETRATION.

1/10

Figure

2.

Effect of temperature on properties of vacuum residue

of sludge containing 2.5

%

aluminum chloride.

a distin ct flash inside the cup on the application of th e test flame

is reported as flash point.

Solubility in carbon disulfide was determined as per IP

47/74

using 2 g of th e dry material and 100mL of carbon d isulfide. Loss

on heating was determined asper IP

45/58

in a stabiltherm oven

(BLUE M Electric

Co., USA) . A

50-g portion of th e sample in

the sample container was placed near the circumference of the

revolving shelf which is made

to

rotate a t a rate of 5 -6 rpm, the

temperature being maintained at

163

C for

5

h after the sample

was introduce d. Density of the samples was determined as per

IP

160/68

usinga hydrom eter of range 0.85490 /mL. Recovery

was determined as per I P 123/78. A 100-mLvolume of th e sample

was distilled, and the to tal volum e of the di stillate collected in

the receiver at

366

O C was recorded as the recovery. Kinem atic

viscosity was determined as per I P

71/60.

The time was measured

for a fixed volume of oilto flow through th e capillary of a calibrated

glass viscometer at

38

C. Th e kinematic viscosity of the oil was

then calculated from th e measured flow time an d th e calibration

constan t of the viscometer obtained using freshly distilled water

as the primary standard.

The diesel index was determined as per IP

21/53.

It was

calculated using the formula

GA/100

where G is the API gravity

and

A

is the aniline point in

O F

The aniline point was determined

as per IP

2/78.

Pure aniline

(5

mL) and sample 5 mL) were

placed in a tube and mixed mechanically. Th e mixture was heated

a t a controlled rate u ntil the two phases became miscible. The

mixture was then cooled at a controlled rate and t he temperature

at w hich the two phases separated was recorded as he aniline

point. Ram sbottom carbon residue was determined

as

per IP

8/10/2019 ef00045a037.pdf

4/5

Utilization of Refine ry Sludge for Lighter Oils

Energy & Fuels, Vol

8 , No.

3, 1994 791

C h a r t

1

A 1%

Atcis

0 2 A l C l j

A 25%A C l j

Z?T/ AlC13

56 64

7 2 80 88

SOFTENING

POINT'C

Fig ure

3. Effect of duration of heat treatment with varying

percentages of aluminum chloride.

A

2 d C

A 2 5 6 C

2 7 d C

225Oc

75 79 6 3

8 7

SOFTENING POINT C

Figure 4 . Effect of duration of heat treatment at varying

temperatur es with

2.5%

aluminum chloride.

14/65. A

5-g portion of the sample was introduced into th e cocking

bulb by means of a hypodermic syringe and the bulb was

reweighed. Th e coking bulb was then placed in the furnace a t

550

C for

20

min. It was then taken out an d placed in a desiccator

density a t

15

C g/mL) (IP

I60/68)

recovery at 366

O C

(vol %

(mL))

IP 123/78)

flashpoint (PMC) C)IP

34/75)

kinematic viscosity at

38

O C (cS) (IP

71/60)

diesel index IP

21/53)

carbon residue (Ramsbottom) (wt % ) (IP

14/65)

aniline point

OC)

IP

2/78)

total sulfur ( w t

%

) (IP 3/65)

pour point ( C) IP 15/67)

0.8923

73

>80

10.6

45

0.29

86.6

1.3

+ 21

over CaClz for

20

min and weighed again. Th e percentage weight

of carbon residue was then calculated and reported as Rams-

bottom carbon residue. Tota l sulfur was determined as per IP

61/65. A0.6-g portion of the sample was subjected to com bustion

using a firing wire of length 100 mm in a bomb of capacity 300

mL containing oxygen at

35

atm pressure. Th e interior of the

bomb and th e cup were then washed with distilled water and th e

washings were collected. Th e washings were the n heate d to

boiling and

10

mL of barium chloride solution was then added

dropwise. Boiling was continued for

5

min more and th e sample

was then cooled. Th e supern atant liquid was then filtered

through a filter paper (W hatman No.

40)

and th e precipitate was

washed until free from chloride. T he paper and th e precipitate

was then tran sferred in to a weighed crucible and ignited until

the residue was white in colour. Th e crucible was the n allowed

to cool to room temperatu re and weighed. Th e percentage weight

of total sulfur was then calculated using the formula

13.73(A/B),

where

A

is weight in grams of barium sulfa te and E is weight in

grams of th e sample taken for test.

Pour point was determined as per IP

15/67.

Th e sample was

heated in a water ba th witho ut stirring to a temperature of 45

OC. The test jar containing the sample was then placed in a

vertical position in the cooling bath. At each multiple of

3

OC

the te st jar was taken out carefully from the cooling bath and

tilted t o ascertain whether the re is a movem ent of the oil in the

test jar. Th e complete operation of removal and replacement

was done within 3 s. Th e test was continued until th e oil in the

test jar showed no movement when the test jar was held in a

horizontal position for exactly 5 s. The reading of the test

thermo meter was recorded a s the pour point.

R e s u l t s and Discussion

T he in i t i al pa r t of th e s tudy demo nst ra tes tha t about

17%of lighter oils can be isolated from this refinery sludge.

Characteristics of th e recovered oil (Ch art

1)

how tha t i t

can be b lended wi th o the r re f ine ry s t reams to make i t

useful as high-speed diesel.

Th e catalyt ic effect on the heat t reatm ent of th e vacuum

residue of the sludge was also investigated. Th e results

of th e action of sulfu r, FeCl3, PzOS,nd AlC13 on th e he at

t r e a t me n t a t 250 C an d a t a catalyst ra t io of 2 % for

3 h

are shown in Table

3.

It is seen th at sulfur, FeCl3, and

Pz05 are successful in bringing down the penetrat ion

sharply bu t fa i l to bring up t he softening point. Bu t AlC13

not only brought down th e pene t ra t ion sharply but was

also able to bring up th e softening point to t he required

level.

The pronounced catalyt ic effect of

AlC13

in such

polymerization reactions involving olefins can be exp lained

by m eans of th e following ionic mechanism. Since AlC13

has an incomplete octet , i t , when added to the olefin,

polarizes i t to such an e x t e n t t ha t it

is

capable of adding

furt her monom ers.l1 At high temp erature s, AlC13 can also

11)Rieche,

Alfred

Outline of Industrial Organic Chemistry;

Butterworth: London, 1964;Chapter 11 p 394.

8/10/2019 ef00045a037.pdf

5/5

792

Energy

& Fuels,

Vol

8, N o 3 994

Kuriakose

and Manjooran

2

2.5

2.75

Table 4: Data

on

Heat Treatment of Vacuum Residue

at 250

OC with Differe nt Percentages of A lClJ for Varying Dura tions

amount of duration of hea t specific softening f lash ma tter soluble loss on

AlC13 (5 ) t rea tme nt (h) gravity point penetra t ion ducti l i ty poin t in CS2 ( w t % ) heating (w t 5 )

1

1.0

1.023

56 30 11

>300 99.76

0.08

1.5

1.023

59 29 9

>300 99.72

0.06

2.0 1.024 62.5

27

6.5 >300 99.70

0.05

2.5

1.026 64 25 6.3 >300 99.68

0.03

3.0

1.026 65 25

6.25 >300 99.65

0.03

1.0

1.025

69 25 6.0

>300 99.74

0.06

1.5

1.026 75 23 5.75 >300 99.72

0.06

2.0 1.028 78 22 5.5 >300 99.70

0.05

2.5 1.030 81 21 5.0 >300 99.67 0.05

3.0 1.030 83 20 5.0

>300 99.64

0.04

1.0

1.028

76 24 5.3

>300

99.72 0.05

1.5 1.028

81 22 5.0 >300 99.69

0.04

2.0 1.029 84 20 4.5 >300 99.64

0.04

2.5

1.032 88 17

3.75 >300 99.60

0.03

3.0 1.034 89 16 3.5

>300 99.59

0.03

1.0 1.028 80 22 5.1

>300 99.68

0.04

1.5

1.030 84

2 1

4.5 >300 99.65

0.04

2.0 1.031

86 20 4.25

>300 99.62

0.03

2.5 1.032

88 18 4.0

>300 99.60

0.03

3.0

1.033

89 17 4.0

>300 99.60

0.03

Table

5:

Data on Heat Treatment with

2.5%

AlC13 at Varying Tem peratures and Duration

t e m p

dura t ion of heat specif ic softening penetrat io n ducti l i ty f lash ma tter soluble

loss on

P C ) t r e a tm e n t ( h )

erav itv Doint ( C)

(1/10

m m )

(cm)

Doint ( C)

in CS2

(w t

% ) heating

( w t

% )

275 1.0 1.025 78 25

1.5

2.0

2.5

3.0

225 1.0

1.5

2.0

2.5

3.0

200 1.0

1.5

2.0

2.5

3.0

1.026 80

1.028 83

1.030 86

1.032 87

1.026 76

1.028 83

1.029 86

1.034 89.5

1.036 90

1.025 75

1.026 79

1.026 81

1.028 83.5

1.028 84.5

23

21

19

18

25

22

18

15

14

29

27

26

25

25

bring about Friedel-Crafts arylation (Sholl reaction). '*

Intramolecular Sholl reaction can also take place.

Table 4 gives the effect of differe nt percentages (ranging

from

1

o 2. 75 % ) of A1C13 a t 250

C

n t he he a t t r e a t me n t

of th e vacuum residue of sludge for periods ranging from

1

to 3 h (Figure

1).

The results show considerable

improvem ent in th e softening point-penetration relation-

shi p upto a catalyst level of 2.5% an d dur atio n of 2.5 h.

With higher percentages, th e imp rovem ent is not signifi-

cant . Table 5 reports the data obtained when the heat

t rea tmen t was ca rr ied ou t a t o the r d i f fe rent t empera tures

ranging from 200 to 275 C for varying periods keeping

the catalyst level a t 2.5% (Figure

2).

The results show

th at a high temp erat ure of 275 C as well as a lower

tem pera ture of 200

C

did n ot give a bette r softening point-

(12)March,

Jerry

Advanced Organic Chemistry-Reactions, Mecha-

nisms and Structure; International Student edition; McGraw-Hill

Kogakusha Ltd. Tokyo 1968; Vol. 11,p

412.

6.0

5.75

5.5

5.0

4.0

5.4

4.75

4.25

3.5

3.0

6.0

5.8

5.75

5.0

5.0

>

300

>

300

>300

>300

>300

>

300

>

300

>300

>

300

>

300

>300

>300

>300

>300

>

300

99.74

99.72

99.70

99.64

99.61

99.70

99.67

99.65

99.59

99.56

99.72

99.70

99.67

99.64

99.63

0.06

0.06

0.05

0.04

0.04

0.05

0.04

0.03

0.02

0.02

0.06

0.06

0.05

0.05

0.05

penetr at ion relat ionship. T he best result was obtained at

the tempe rature of 225 C and durat ion of 2.5 h. This can

be taken to be the o ptimum conditions for preparing grades

of industrial bitumen of lower penetration and higher

softening point like 90115.

T he results show tha t only four of th e 10 different grades

of industria l bi tumen can be prepared by the methods

used in the present study. Heat t rea tm ent of the vacuum

residue a t 250 C for 2.5 h with

1

% AlC13 is suff icien t fo r

preparing th e 65/25 grade. T he 75/30 and 85/25 grades

can be obtained by heat t reat me nt a t 200 C with 2.5%

AlC13 fo r 1 and 3 h, respectively. Similarly, 90115 grade

can be prepared by hea t t reatme nt a t 225 C for 2.5 h with

2.5

%

AlC13. For th e remaining grades, th e softeningpo int-

pene trat ion specificat ions were found difficul t to m eet by

the m ethods used in thi s study, probably due to the low

asph altene content in th e vacuum residue of sludge.