ISO 4262:1993

INTERNATIONAL
ISO
STANDARD
Second edition
1993-09-15
Petroleum products - Determination of
carbon residue - Ramsbottom method
Produits p6 troliers - Dbtermination du r&idu de carbone - Methode
Ramsbottom
Reference number
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 4262 was prepared by Technical Committee
ISO/lC 28, Petroleum products and lubricants.
This second edition cancels and replaces the first edition
(ISO 4262:1978), which has been technically revised.
Annex A forms an integral part of this International Standard. Annex B is
for information only.
0 ISO 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronie or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
lnternational Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland
ii
INTERNATIONAL STANDARD ISO 4262:1993(E)
Petroleum products - Determination of carbon
residue - Ramsbottom method
of this International Standard. At the time of publi-
1 Scope
cation, the editions indicated were valid. All Standards
are subject to revision, and Parties to agreements
This International Standard specifies a method for
based on this International Standard are encouraged
determining the amount of carbon residue, in the
to investigate the possibility of applying the most re-
range of 0,Ol % (m/m) to 30,O % (m/m), left after
cent editions of the Standards indicated below.
evaporation and pyrolysis of an Oil, and is intended to
Members of IEC and ISO maintain registers of cur-
provide some indication of relative Coke-forming
rently valid International Standards.
tendency. The method is generally applicable to rela-
tively non-volatile Petroleum products which partially
ISO 683-13: 1986, Hea t-trea table s teels, alloy s teels
decompose on distillation at atmospheric pressure.
and free-cutting steels - Part 13: Wrought stainless
NOTES s teels.
1 The term “carbon residue” is used throughout this In-
ISO 3170:1988, Petroleum liquids - Manual
ternational Standard to designate the carbonaceous residue
sampling.
formed during evaporation and pyrolysis of a Petroleum
product. The residue is not entirely composed of carbon, but
ISO 3171 :1988, Petroleum liquids - Automatic pipe-
is a coke which tan be further changed by pyrolysis. The
line sampling.
term “carbon residue” is retained in this method only in
deference to its widespread use.
ISO 3405: 1988, Petroleum products - Determination
of dis tilla tion characteris tics.
2 The carbon residue of distillate and residual fuel oils
gives an approximate ranking of such fuels in terms of their
propensity to form deposits in specific applications.
3 Principle
3 The presence of alkyl nitrates in distillate fuels, or ash-
forming additives in either distillate or residual fuels, will
3.1 The test Portion is weighed into a glass coking
give carbon residue results that are higher than the corre-
bulb having a capillary opening, and is placed in a
sponding values of the fuel without additives. These values
metal furnace maintained at a temperature of ap-
may not correlate with the propensity of a fuel to form de-
proximately 550 “C. The test Portion is thus quickly
posits.
heated to the Point at which all volatile matter is
4 The carbon residue of base lubricating oils may give an
evaporated out of the bulb with or without decom-
indication of the propensity of the oil to lay down deposits
Position, while the heavier residue remaining in the
in combustion chambers, and/or of the relative Chemical
bulb undergoes cracking and coking reactions. In the
constitution of oils of similar viscosity. Most finished lubri-
later stages of the heating period, the coke or carbon
cating oils contain ash-forming additives, and thus the car-
residue is subject to further slow. decomposition or
bon residue of finished lubricants cannot be used in this
slight Oxidation due to the possibility of air being
manner.
drawn into the bulb. After a specified heating period,
the bulb is removed from the furnace, cooled in a
5 The carbon residue of a gas oil is a useful guide in the
dessicator, and again weighed. The residue remaining
manufacture of gas.
is calculated as a mass percentage of the test Portion.
2 Normative references
3.2 Provision is made for determining the proper
operating characteristics of the furnace with a control
The following Standards contain provisions which,
bulb containing a thermocouple, which gives a speci-
through reference in this text, constitute provisions
fied time-temperature relationship.

Dimensions in millimetres
3.3 For light products where over 90 % (VW) distils
at below 370 “C, the procedure may be carried out on
the residue remaining after 90 % (VW) has been dis- - Capillary length
tilled. The procedure for obtaining this residue is given
@8
in annex A. @7
- 5
@ 2,0
@ IS Capillary, free
a--a
4 Apparatus
of constrictions
4.1 Glass cokinb bulb, made of heat-resistant
glass, and conforming to the dimensions and toler-
ances shown in figure 1.
Prior to use, check the diameter of the capillary to see
that it is greater than 1,5 mm and not more than
2,0 mm. Pass a 1,5 mm diameter drill rod through the
capillary and into the bulb; attempt to pass a 2,0 mm
diameter drill rod through the capillary. Reject bulbs
I I
I I I
Y 1,4
m
that do not permit the insertion of the smaller rod and c
those whose capillaries are larger than the larger rod.
4.2 Control bulb, for use in determining compliance
Hemispherical inside
of furnace characteristics with the Performance re-
rradius z 11 mm
/
/
quirements (see clause 5). Made of stainless steel,
I
I
t
I
containing a thermocouple and conforming to the tol-
\
:
erances shown in figure 2. The control bulb shall be
\
\
1’
\
provided with a dull finish by heating in a furnace at
\
1’
\
/
\
a temperature of 850 “C to 900 “C for 30 min, and “y/
\
/
\
/
N
,))
shall not be polished thereafter, as a polished bulb has --a
ii
different heating characteristics from one with a dull
@ 252
finish.
# 24,2 I
A suita ble th ermocouple pyrometer for observ ing true
te mperature within + 1 “C is also requ red.
Figure 1 - Glass coking bulb
4.3 Syringe, for test Portion charging. A 5 ml or
IO ml glass hypodermic Syringe fitted with a needle
be immersed in the molten metal to leave not more
of 1,5 mm outside diameter or a Serum needle of
than 3 mm of the bulb weil exposed above the molten
1,45 mm to 1,47 mm outside diameter, for transfer
metal at operating temperatures.
of the test Portion to the glass coking bulb.
one type of furnace wh ich has
NOTE 7 A description of
NOTE 6 A Syringe having a needle which fits on the
ry is given in annex B.
been fou n d to be satisfacto
ground glass tip of the Syringe is not recommended, as it
may be blown off when pressure is applied to the Syringe
4.5 Temperature-measuring devices. A removable
plunger. Locking-type syringes are more satisfactory, as the
iron-constantan thermocouple with a sensitive
needle locks on the bottom of the Syringe barrel, and cannot
pyrometer, or other suitable temperature-indicating
be blown off by pressure.
device shall be used, located centrally near the bot-
tom Portion of the furnace and arranged to measure
4.4 Metal coking furnace, constructed of solid
the temperature of the furnace, thus enabling the
metal, having coking bulb wells 25,45 mm + 0,l mm
performante tests specified in clause 5 to be carried
in internal diameter and 76 mm deep to the centre of
out.
the well bottom, with suitable arrangements for
heating to a uniform temperature of 550 “C. The bot-
NOTES
tom of the well shall be hemispherical to accommo-
date the bottom of the glass coking bulb (4.1).
8 When a molten bath is used, it is desirable to protect the
temperature-indicating device with a quartz or thin metal
DO not cast or otherwise form the furnace with un-
sheath.
necessary voids which will impede heat transfer.
9 lt is good practice to calibrate the thermocouple or other
If a molten metal furnace is used, provide it with a
temperature-measuring device against a Standard
suitable number of bulb wells, the internal dimensions
thermocouple or a reference Standard approximately once
of which correspond to the internal dimensions of
a week when the furnace is in constant use, the actual fre-
holes in the solid metal furnace. The bulb wells shall quency depending on experience.

Dimensions in miliimetres
Tolerante on dimensions f 0,4 unless othervvise stated
@ 25,02
@ ext. 6,4
length 64
Ceramic insulator with two holes
!
for thermocouple 0,s mm wires
Iron-constantan thermocouple,
0,s mm wires
Double glass-lapped and silicone-
impregnated 1 500 mm lang with M
two holes for thermocouple wires
Stainless steel
Austenitic stainless
R 0,8
Wall thickness 0,9 mm steeL ‘Onforming t”
ISO 683-13
stainless steel
Threaded
Hemispherical outside
radius 12,4 mm to 12,7 mm
NOTE - Total mass of control bulb less thermocouple: 24 g k 1 g
Figure 2 - Control bulb
coking bulb well while the bath is fully loaded as well
5 Verification of apparatus Performance
as singly Ioaded. Once these criteria have been met,
use the furnace with any degree of loading. Use only
a furnace that has successfully undergone the per-
formante or control tests given in this clause.
5.1 General
Periodically check the Performance of the furnace
(4.4) and temperature-measuring devices (4.5) as de- 5.2 Thermocouple
scribed in 5.2 to 5.4 to ensure that as used they con-
form to the requirements of the method. Consider the Calibrate the thermocouple in the control bulb against
furnace as having Standard Performance when the a Standard thermocouple at least once every 50 h of
operating requirements described are met by each
use of the control bulb (4.2).

NOTE 10 During use at the high temperature of the test,
6 Samples and sampling
iron-constantan thermocouples oxidize and their calibration
curves Change.
6.1 Obtain samples in accordance with ISO 3170,
ISO 3171 or an equivalent national Standard.
5.3 Fully-loaded furnace
6.2 Products examined by this International Stan-
When the furnace temperature is within a previously dard are not always completely homogeneous, and
Chosen 2 “C temperature range within the general therefore appropriate precautions shall be taken dur-
range 550 “C + 5 “C (which is to be used thereafter ing the procurement of both bulk and laboratory test
with that part%ular furnace for both standardization samples (see 7.2).
and routine Operation), insert the control bulb (4.2) in
one weil. Within 15 s, insert in each of the other wells
7 Test procedure
a glass coking bulb (4.1) containing 4 g $- 0,l g of a
viscous neutral Petroleum lubricating oil with a vis-
cosity within the range 60 mm*/s to 100 mm*/s at
7.1 Place a new glass coking bulb (4.1) (see
40 “C. With a suitable accurate Potentiometer or
note 11) in the coking furnace (4.4) at 550 “C for ap-
millivoltmeter (sensitive to 1 “C or less), observe the
proximately 20 min to decompose any foreign organic
temperature rise in the control bulb at 1 min intervals
matter and to remove water. DO not re-use a glass
for 20 min. If the temperature in the control bulb
coking bulb, as unpredictable results tan be obtained
reaches 547 “C in not less than 4 min and not more
in such cases. Place the bulb in a closed desiccator
than 6 min from the instant of its insertion in the fur-
over Calcium chloride or silica gel for 20 min to
nace, and remains within the range 550 “C + 3 “C for
30 min and then weigh to the nearest 0,l mg.
the remaining Portion of the 20 min test, cokider that
particular coking bulb well to be suitable for use as a NOTE 11 For routine testing, new bulbs may be used
without pre-ignition provided that they are visibly free from
“Standard Performance weil” when the furnace is
particles or other contamination.
used fully loaded. Check each weil in a similar fashion,
with the furnace fully loaded each time.
7.2 Shake thoroughly the oil Sample to be tested,
first warming if necessary to reduce its viscosity.
5.4 Singly-loaded furnace
Strain the Sample through a 150 Pm wire sieve. By
means of the hypodermic Syringe (4.3) or the device
When the furnace temperature is within a previously shown in figure3, introduce into the coking bulb an
Chosen 2 “C temperature range within the general amount of Sample as indicated in table 1. Ensure that
range 550 “C + 5 “C (which is to be used thereafter no oil remains on the exterior surface or on the inside
with that pa&ular furnace for both standardization of the neck of the bulb. Reweigh the bulb and con-
and routine Operation), insert the control bulb (4.2) in tents to the nearest 0,l mg.
one weil, with the remaining wells unoccupied. With
a suitable accurate Potentiometer or millivoltmeter
Table 1 - Test Portion mass
s
(accurate to 1 “C or less), observe the temperature
rise in the control bulb at 1 min intervals for 20 min.
Ramsbottom carbon residue Test Portion mass
If the temperature in the control bulb reaches 547 “C
% (dm)
g
in not less than 4 min and not more than 6 min from
the instant of its insertion in the furnace, and remains
6,00 410 * 03
<
within the range 550 “C + 3 “C for the remaining
Portion of the 20 min test, consider that particular
LO zt 03
6,00 to 14,0
coking bulb weil to be suitable for use as a “Standard
* 0,1
14,l to 30,o 0,5
Performance well” when the furnace is used with
only a Single bulb. Check e
...