ISO 4262:1978

INTERNATIONAL STANDARD 4262
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MEmDYHAPOllHAR OPrAHH3AUMfl il0 CTAH~AFTH3AUHHDORGANlSATlON INTERNATIONALE DE NORMALISATION
Petroleum products - Determination of carbon residue -
Ramsbottom method
Produits pétroliers - Détermination du carbone résiduel - Méthode (( Ramsbottom n
First edition - 1978-02-15
UDC 665.7 : 543.824 Ref. No. IS0 4262-1978 (E)
Descriptors : petroleum products, chemical analysis, determination of content, carbon, coking.
Price based on 9 pages

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FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 member bodies). The work of developing
International Standards is carried out through IS0 technical committees. Every
member body interested in a subject for which a technical committee has been set
up has the right to be represented on that committee. International organizations,
ISO, also take part in the work.
governmental and non-governmental, in liaison with
Draft International Standards adopted by the technical committees are circulated
to the member bodies for approval before their acceptance as International
Standards by the IS0 Council.
International Standard IS0 4262 was developed by Technical Committee
ISO/TC28, Petroleum products, and was circulated to the member bodies in
May 1976.
It has been approved by the member bodies of the following countries :
Australia India Portugal
Austria Iran Romania
Belgium Ireland South Africa, Rep. of
Brazil Israel Spain
Canada Italy Sweden
Korea, Rep. of Turkey
Chile
Czechoslovakia Mexico United Kingdom
Netherlands
Egypt, Arab Rep. of U.S.A.
France Peru
U.S.S.R.
Germany Philippines
Poland
Hungary
No member body expressed disapproval of the document.
O International Organization for Standardization, 1978
Printed in Switzerland

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INTERNATIONAL STANDARD
IS0 4262-1978 (E)
Petroleum products - Determination of carbon residue -
Ramsbottom method
1 SCOPE AND FIELD OF APPLICATION
2 REFERENCE
IS0 3405, Petroleum products - Determination of
1.1 This International Standard specifies a method for
distillation characteristics.
determining the amount of carbon residue (see note) left
after evaporation and pyrolysis of an oil, and is intended to
provide some indication of relative coke-forming tendency.
The method is generally applicable to relatively non-volatile
3 PRINCIPLE
petroleum products which partially decompose on
distillation at atmospheric pressure.
The test portion, after being weighed into a glass
3.1
NOTE - The term "carbon residue" is used throughout this method
coking bulb having a capillary opening, is placed in a metal
to designate the carbonaceous residue formed during evaporation
furnace maintained at a temperature of approximately
and pyrolysis of a petroleum product. The residue is not entirely
550 OC. The test portion is thus quickly heated to the point
composed of carbon, but is a coke which can be further changed
at which all volatile matter is evaporated out of the bulb
by pyrolysis. The term "carbon residue" is retained in this method
only in deference to its widespread use.
with or without decomposition while the heavier residue
remaining in the bulb undergoes cracking and coking
reactions. In the later stages of the heating period, the coke
or carbon residue is subject to further slow decomposition
1.2 The carbon residue value of burner fuel serves as a
or slight oxidation due to the possibility of air being drawn
rough approximation of t,he tendency of the fuel to form
into the bulb. After a specified heating period, the bulb is
deposits in vaporizing pot-type or sleeve-type burners. The
removed from the furnace, cooled in a desiccator, and again
carbon residue value of gas oil is useful as a guide in the
weighed. The residue remaining is calculated as a percentage
manufacture of gas from gas oil, while carbon residue values
of the test portion, and reported as Ramsbottom carbon
of crude oil residues, cylinder oils and bright stocks, are
residue.
useful in the manufacture of lubricants.
I
3.2 Provision is made for determining the proper operating
characteristics of the furnace with a control bulb containing
1.3 The following anomalous cases should be noted :
a thermocouple, which shall give a specified time-
temperature relationship.
a) Motor oils. The carbon residue value of motor oil,
while at one time regarded as indicative of the amount
of carbonaceous deposits a motor oil would form in the
3.3 If a product has a Ramsbottom carbon residue of less
combustion chamber of an engine, is now considered to
than 0,l %, the procedure is modified by carrying out the
be of doubtful signifiance due to the presence of
test on a 10 % distillation residue.
additives in many oils. For example, an ash-forming
detergent additive may increase the carbon residue value
of an oil yet will generally reduce its tendency to form
deposits.
4 APPARATUS
b) Diesel fuels. The carbon residue value of diesel oils
containing amyl nitrate is erroneously high. If, however,
4.1 Glass coking bulb, of heat-resistant glass, conforming
the test is carried out on diesel fuels not containing amyl
to the dimensions and tolerances shown in figure 1. Prior to
nitrate or on the base fuel to be blended with amyl
use, check the diameter of the capillary to see that it is
nitrate, the carbon residue value correlates
greater than 1,5 and not more than 2,O mm. Pass a 1,5 mm
approximately with combustion chamber deposits.
diameter-drill rod through the capillary and into the bulb;
c) Petroleum products containing ash-forming additives
attempt to pass a 2,O mm diameter drill rod through the
may give carbon residue values which may not correlate
capillary. Reject bulbs that do not permit the insertion of
with the tendency to form deposits and may be higher
the smaller rod and those whose capillaries are larger than
than the corresponding tendency to form deposits.
the larger rod.
1

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IS0 4262-1978 (E)
Dimensions in millimetres
The capillary shall be
7 to 8
free of constrictions.
FIGURE 1 - Glass coking bulb
4.2 Control bulb, stainless steel, containing a thermo-
4.4 Metal coking furnace, of solid metal, having coking
couple and conforming to the dimensions and tolerances
bulb wells 25.5 It 0,l mm in internal diameter and 76 mm
shown in figure 2, for use in determining compliance of
deep to the centre of the well bottom, with suitable
furnace characteristics with the performance requirements arrangements for heating to a uniform temperature of
(see clause 5). The control bulb shall be provided with a
550°C. The bottom of the well shall be hemispherical to
dull finish, by heating in a furnace at a temperature of 850 accommodate the bottom of the glass coking bulb 14.1 ).
to 900 OC for 30 min, and shall not be polished thereafter. Do not cast or otherwise form the furnace with unnecessary
A polished bulb has different heating characteristics from voids which will impede heat transfer. If a molten metal
one with a dull finish. A suitable thermocouple pyrometer furnace is used, provide it with a suitable number of bulb
for observing true temperature within lr 1 "C is also wells, the internal dimensions of which correspond to the
required. internal dimensions of holes in the solid metal furnace. The
leave
bulb wells shall be immersed in the molten metal to
not more than 3mm of the bulb well exposed above the
4.3 Test portion charging syringe, 5 or 10 ml glass hypo-
molten metal at operating temperatures.
dermic syringe fitted with a needle of 1,5 mm outside
diameter or a serum needle of 1,45 to 1,47 mm outside
i
diameter, for transfer of the test portion to the glass coking
bulb.
NOTE - Ramsbottom coke furnaces now in use may have
NOTE - A syringe having a needle which fits on the ground glass tip dimensions which differ from those given in 4.4. However, it is
of the syringe is not recommended, as it may be blown off when strongly recommended that new furnaces obtained after the
pressure is applied to the syringe plunger. The Luer-Lok type adoption of this method conform to the requirements outlined in
syringes are more satisfactory, as the needle locks on the bottom 4.4. A description of one type of furnace which has been found to
of the syringe barrel, and cannot be blown off by pressure. be satisfactory is given in the annex.
2

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IS0 4262-1978 (E)
Dimensions in millimetres
Ironconstantan thermocouple,
0,5 wires
Double glass-lapped and silicone-
impregnated 1 500 long with two -
holes for thermocouple wires
@ 24,05 to 25,05 /
Ceramic insulator
with two holes for
-. 0,70 to 0,75
@ ext. 4, length 63,5 thermocouple 0.5 wires
I
. 6.4 Wall thickness 0,9,
An austenitic
stainless steel
stainless steel
- - - Stainless steel
I from IS0 683/X I I I
outside radius
h I
c @ 5,5
O --_I --
4-
m.
v-
Total mass of control
less thermocouple :
bulb
241 1 g -@
Tolerance on dimensions * 0.1
unless otherwise stated
FIGURE 2 -Control bulb
4.5 Temperature-measuring c-vices : a removable iron- standard performance, and use it with any degree of
constantan thermocouple with a sensitive pyrometer, or loading, when the operating requirements described for
other suitable temperature-indicating device, located each coking bulb well are met, while the bath is fully
centrally near the bottom portion of the furnace and loaded as well as singly loaded. Use only a furnace that has
arranged to measure the temperature of the furnace so that successfully undergone the performance or control tests
tests specified in clause 5 can be carried given in this clause.
the performance
out. It is desirable to protect the temperature indicating
device with a quartz or thin metal sheath when a molten
5.1 Thermocouple
bath is used.
At least once every 50 h of use of the control bulb (4.2),
NOTE - It is good practice to calibrate the thermocouple or other
calibrate the thermocouple in the control bulb against a
temperature-measuring device against a standard thermocouple or a
standard thermocouple.
reference standard about once a week when the furnace is in
constant use, the actual frequency depending on experience.
NOTE - In use at the high temperature of the test, iron-constantan
thermocouples oxidize and their calibration curves change.
5 CHECKING PERFORMANCE OF APPARATUS
5.2 Fully loaded furnace
Periodically check the performance of the furnace (4.4) and
When the furnace temperature is within a previously
temperature-measuring devices (4.5) as described in 5.1 to
2 "C temperature range (which range is to be used
5.3 to make certain that as used they conform to the chosen
as having thereafter with that particular furnace for both standard-
requirements of the method. Consider the furnace
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IS0 4262-1978 (E)
chloride or silica gel for 20 to 30 min and then weigh to
ization and routine operation) and within the general range
the nearest 0,l my.
550 1: 5 OC, insert the control bulb (4.2) in one well and,
within 15 s, insert in each of the other wells a glass coking
NOTE - Do not re-use a glass coking bulb, as unpredictable results
bulb (4.1) containing 4 f 0,l g of a viscous neutral
are sometimes obtained in such cases. For routine testing, new bulbs
petroleum lubricating oil with a viscosity within the range
may be used without pre-ignition provided that they are visibly free
from particles or other contamination. All new bulbs should be
60 to 100 mmZ/s* at 4OoC. With a suitable accurate
heated in an oven to 15OoC, placed in a desiccator, and then
potentiometer or miiiivoitmeter (sensitive to I OC or less),
weighed to the nearest 0.1 mg.
observe the temperature rise in the control bulb at 1 min
20 min. If the temperature in the control bulb
intervals for
reaches 547 OC in not less than 4 and not more than 6 min
6.2 Shake thoroughly the sample to be tested, first
from the instant of its insertion in the furnace, and remains
warming if necessary to reduce its viscosity. Strain the
within the range 550 I3 OC for the remaining portion of
a 150 pm wire sieve. By means of the hypo-
sample through
the 20 min test, consider that particular coking bulb well to
dermic syringe (4.3) or the device shown in figure3,
be suitable for use as a "standard performance well" when
introduce into the coking bulb an amount of sample as
is used fully loaded. Check each well in similar
the furnace
indicated in the table. Make sure that no oil remains on the
fashion with the furnace ful!y loaded each time.
exterior surface or on the inside of the neck of the bulb.
Reweigh the bulb and contents to the nearest 1 mg. If
difficulty is encountered in loading very viscous or asphaltic
5.3 Singly loaded furnace
test portions, of whatever size, into the glass coking bulb,
When the furnace temperature is within a previously chosen the apparatus shown in the annex may be used.
2 OC temperature range (which range is to be used
NOTE - When obtaining the test portion of oils containing
thereafter with that particular furnace for both standard-
it is important to make the
sediment (for example, used oils),
ization and routine operation) and within the general range
tran
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