This document reports on an experiment to determine the smoke point of kerosene and diesel fuels. Smoke point is a measure of how high a flame can burn without producing smoke, with higher values indicating less smoke production. For kerosene, the average smoke point was 21.5 mm, corresponding to a smoking tendency of 14.8. For diesel, the average smoke point was lower at 19.5 mm, with a smoking tendency of 16.44. The differences are attributed to diesel having higher aromatic content, which produces more smoke. Factors like apparatus calibration and fuel composition can affect smoke point measurements. Smoke point is an important property used to evaluate fuel quality, design combustion devices, and ensure safety.

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Duhok Polytechnic University
CollageTechnical of Engineering
Department of Petrochemical
(SMOKE POINT )
Amar Askander
Group. B
Report No. EXP 5
Date of the lecture 03/04/2019
Delivery date. 10/04/2019
BY:

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Contents
5.1 Objectives----------------------------------------------------------------- Page 3
5.1 Introduction--------------------------------------------------------------- Page 3
5.1 Apparatus and Materials------------------------------------------------ Page 4
5.2Procedure ------------------------------------------------------------------ Page 5
5.5 Results and Calculations -------------------------------------- ----- ----Page 5
5.6 Discussion -----------------------------------------------------------------Page 6
5.7 Conclusion-----------------------------------------------------------------Page 10
5.8 Reference ---------------------------------------------------------------Page 10

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5.1 Objectives
Determination of Smoke point of kerosene and Diesel.
5.1 Introduction
The smoke point is the maximum flame height in millimeters at which kerosene
will burn without smoking, tested under standard conditions, this test method provides
an indication of the relative smoke producing properties of kerosene and aviation
turbine fuels in a diffusion flame. The smoke point is related to the hydrocarbon type
composition of such fuels. Generally the more aromatic the fuelthe smokier the flame.
A high smoke point indicates a fuel of low smoke producing tendency.[ref 1]
As the wick of a yellow-flame type lamp is turned up, a point is reached where smoking
occurs. Therefore. the degree of illumination possible depends mainly on the height of
the nonsmoking flame obtainable. This height varies according to the hydrocarbon type
composition of the kerosene. The maximum height of flame obtainable without
smoking, termed the "smoke point." is greatest with paraffin’s. Considerably lower
with naphthenic and much lower still with aromatics.
As the smoke point is high like the paraffinic compounds it will have low smoking
tendency ( less able to produce smoke). Inversely, the low smoke point like in aromatic
compounds has high smoking tendency to produce smoke.
Smoking tendency can be calculated by the simple formula below:
𝑆𝑚𝑜𝑘𝑖𝑛𝑔 𝑡𝑒𝑛𝑑𝑐𝑒𝑦 =
320
𝑆𝑚𝑜𝑘𝑖𝑛𝑔 𝑝𝑜𝑖𝑛𝑡 𝑖𝑛 𝑚𝑚
Also smoke point may be estimated from either the PNA (Paraffin, naphthenic, and
aromatic ) composition or from the aniline point of kerosene.
𝑆𝑃 = 1.65 × 0.0112𝑋2
−8.7
𝑋 =
100
0.61 𝑋 𝑃 +3.392 𝑋 𝑁 +13.518 𝑋𝐴
𝑆𝑃 = −255.26+2.04 𝐴𝑃 −240.8 ln( 𝑆𝐺) +7727(
𝑆𝐺
)
𝐴𝑃
Where SP is the smoke point in mm, XP ,XN ,and XA are the fractions of paraffin, naphthene, and
aromatic content of kerosene, AP is the aniline point in o
C, and SG is the specific gravity at 15.5 o
C.

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5.1 Apparatus and Materials
1. Smoke point lamp. Show in figure (1).
2. Wick, of woven solid circular cotton of ordinary quality. Shown in figure(2).
3. Wick tube. Shown in figure (3).
4. Candle. Shown in figure (4).
5. Sample of kerosene and diesel fuel.
Figure(1) Figure(2)
Figure(3) Figure(4)

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5.2 Procedure
6. A 126 mm long dried wick is soaked in the sample and placed in the wick
tube of the candle.
7. A 10-20 ml of prepared sample is introduced at room temperature into the
dry candle.
8. The wick tube is placed in the candle firmly with taking care of the candle
air vent is free from fuel. A new clean, sharp razor is used to cut the wick
at the face of the holder and remove wisps and frayed ends.
9. The candle is lighted and the wick adjusted so that the flame is
approximately 10 mm high with 5 min.
10. After burning, the candle raised until a smoky tail appears, then the candle
is lowered slowly through several stages of flame appear once.
11. The maximum height of flame that can be achieved without smoking is
determined to the nearest 0.5 mm.
12. The candle is removed from the lamp arise with heptane and purged with
air to make ready for re-use.
5.2 Result and Calculations
In this experiment we have to record the height of the flame, when we raise the
candle until a smoky tail appears then lower the flame slowly until the smoky tail
disappears, To eliminate errors due to parallax, the eye of the observer shall be slightly
to one side of the centerline, so that a reflected image of the flame is seen on the scale
on one side of the central vertical white line. We have recorded the following records:
For kerosene:
Record of height in mm (2) = 22 mm
Record of height in mm (3) = 24 mm
𝑇ℎ𝑒 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑜𝑓 𝑟𝑒𝑐𝑜𝑟𝑑𝑠 = 21+20 = 21.5 𝑚𝑚
2
𝑆𝑚𝑜𝑘𝑖𝑛𝑔 𝑡𝑒𝑛𝑑𝑐𝑒𝑦 =
320
𝑆𝑚𝑜𝑘𝑒 𝑝𝑜𝑖𝑛𝑡
=
320
21.5
= 14.8
For Diesel:
Record of height in mm (1) = 19 mm
Record of height in mm (2) = 18 mm
𝑇ℎ𝑒 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑜𝑓 𝑟𝑒𝑐𝑜𝑟𝑑𝑠 = 18 + 19 = 19 .5 𝑚𝑚
2

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𝑆𝑚𝑜𝑘𝑖𝑛𝑔 𝑡𝑒𝑛𝑑𝑐𝑒𝑦 =
320
𝑆𝑚𝑜𝑘𝑒 𝑝𝑜𝑖𝑛𝑡
=
320
=16.44
19.5
.
5.2 Dissuasion
13. Compare betweenthe results of the two samples and discuss the reasons
the cause this different?
In this experiment we have used two different samples, they are (kerosene) and
(Diesel) they are both produced from Tawke refinery which has 26-27 degree API
gravity oil [ref.2], for kerosene we have got an average of 24.6 mm smoke point thus
low smoking tendency, this values due to the low aromatic contents of kerosene
compared with lower distillation fractions (Gas oil , Diesel , light gas oil and heavygas
oil)(shown in figure(6)) , the higher the paraffinic contents the higher the smoke point
and lower smoking tendency, and the inversely is correct.
And for (Diesel) we got we have recorded an average of 19 mm smoke point which is
lower than the smoke point of (kerosene), this different due to the higher aromatic
contents of the (Diesel) which effect on the smoke point, as (Diesel) has low smoke
point it will have higher smoking tendency than (kerosene).
From this comparison we can conclude that smoking tendency is increase with the
increase of carbon atoms of petroleum fraction (increasing of aromaticity), so the first
product of distillation tower will have the lowest smoking tendency, and the last
product of distillation tower will have the highest smoking tendency.
Also for products that are similar with carbon atoms number and vary in number of
hydrogen atoms like pure benzene (C6H6) and cyclohexyen (C6H12) , the ratio of
carbons atoms to hydrogen atoms C/H define the smoking tendency of them, if the ratio
C/H increased smoking tendency will increase and smoke point will decrease, and the
inversely is correct.

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Figure (6) : shows distillated fractions of crude oil and its carbon atoms, boiling point
range, and its uses.
14. What are factors that affect measurement of smoke point?
Factors that affect measurement can be the conditions that of the experiment, first of
all the apparatus of smoke point lamp should be calibrated and adjusted carefullyto be
used, and the experiment should be done on straight place and should not be inclined,
the wick type also effect on the accuracy of the this test, so we have to use specific
wick (wick of woven solid circular cotton) for this test to get accuracy results, also it
should be done in a place with absence of air currents, the watching angel also affect
the measurement of this experiment.
15. Why do we measure the smoke point of kerosene?
Smoke point is been measured for different purposes, some of them:
1. For Designing purpose: many apparatus that we use in daily life use the fuel
to produce a flame that we use it for various acts, like cooking, heating
burning and lighting, determining the smoke point is important for this area
of designing, so designers can make apparatus with high quality and
efficiency to use, and don’t give off smoke while being use. For example
lamp that we use for lighting, if you increases the wick up it will give off
smoke of it.
2. For quality purpose: as we know that kerosene produced from different
refineries has different kerosene qualities, kerosene quality is being defined

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from the kerosene properties like (density , specific gravity , flash point ,
smokepoint, cloud point, freezing point , etc… ) , so determining smoke point
of keroseneone of the important properties that should be defined to classify
the kerosene quality.
3. For safety and environmentalpurpose: when the kerosene burns with a smoky
flame inside a closed room, it will produce toxic gases that may hurts human
health and cause diseases, also it smoke will damage the environment.
4. How we can improve the smoke point of kerosene?
In order to improve the smoke point of kerosene we have to decrease the smoking
tendency, this task can be done by increasing the paraffinic contents of kerosene and
also by decreasing the ratio of C/H of kerosene by increasing the number of hydrogen
atoms.
Kerosene hydrotreating play a role in imporving the smoke point of kerosene, The
objective of kerosene hydrotreating is to upgrade raw kerosene distillate to produce
specification products suitable for marketing as kerosene and jet fuel. Sulfur and
mercaptans in the raw kerosene cuts coming from the crude distillation unit can cause
corrosion problems in aircraft engines and fuel handling and storage facilities. Nitrogen
in the raw kerosene feed from some crude oils can cause color stabilityproblems in the
product. For aviation turbine fuels (ATF), the ASTM distillation, flash point, and freeze
point of the hydrotreated kerosene cut has to be rigorously controlled to meet the
stringent requirements. This is done by distillation in a series of columns to remove
gases, light ends, and heavy kerosene fractions. The upgrading is achieved by treating
hydrogen in the presence of a catalyst, where sulfur and nitrogen compounds are
converted into hydrogen sulfide and ammonia.
5. Which hydrocarbons burns with more smoke? And why?
Aromatic compounds burns with more smoke, because it contain more carbons and
heavy fractions that burns with smoke, while paraffinic compounds burn with less
smoke because it contain less carbons in it. The higher the aromatic contents the higher
smoking tendency, while the higher paraffinic contents the lower smoking tendency.
6.
Givens: kerosene API gravity = 41.2 , AP = 55.6 o
C
Paraffinic% = 36.4%
Naphtha% = 49.3%
Aromatic% = 14.3%
Required: Smoke point = ?

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Solution
From equation (1)
𝑆𝑃 = 1.65𝑋−0.0112𝑋2
−8.7 ---------------------------------------------- (1)
𝑋 =
100
0.61𝑋 𝑃 + 3.392 𝑋 𝑁 +13.518 𝑋 𝐴
=
100
(0.61 × 0.364) +(3.392× 0.493) +(13.518× 0.143)
= 26.12
𝑆𝑃 = (1.65 × 26.12) −(0.0112× (26.12)2) −8.7 =26.77 𝑚𝑚
𝐴𝑆𝑇𝑀 = 𝐼𝑃 − 0.7 =26.77 −0.7 =26.07 𝑚𝑚
From equation (2)
= −255.26 +2.04 𝐴𝑃 −240.8 ln( 𝑆𝐺) +7727( 𝑆𝐺)---------------------(2)
𝐴𝑃
𝐴=
141.5
−131.5 ≫ 𝑆𝐺 =
141.5
𝑆𝐺
𝑆𝐺 =
141.5
41.2 +131.5
= 0.819
𝐴𝑃𝐼 𝑔𝑟𝑎𝑣𝑖𝑡𝑦 +131.5
( )
(
0.819
= −255.26 +(2.04 × 55.6) −(240.8 ×ln
= −255.26 +113.42− (−48.08) +113.82
= 20.08 𝑚𝑚
𝐴𝑆𝑇𝑀 = 𝐼𝑃 − 0.7 =20.08 −0.7 =19.38 𝑚𝑚
The error% of result of equation (1)
0.819 ) + 7727
55.6
)
𝑒𝑟𝑟𝑜𝑟% =
26.07 −20
20
× 100 = 30.35%
The error% of result of equation (1)
𝑒𝑟𝑟𝑜𝑟% =
19.38 −20
20
× 100 = −3.1%
The result of equation 2 is more accuracy from result of equation 1 .

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5.2 Conclusion
The smoke point is determined as the height of the flame (in millimeters) produced
by this oil in the wick of a stove or a lamp without forming any smoke. The greater
the smoke point, the better the burning quality. Domestic kerosene should have a
smoke point of 20 mm (minimum). This is measured in a standard testing apparatus
consisting of a standard lamp with a wick of specified dimension and mass. In this
apparatus, a mirror is provided to position the flame in the center such that the straight
height of the flame can be measured in a graduated scale. Smoke is produced mainly due to
the presence of carbon and heavy hydrocarbon particles in the flue gas. The presence of
aromatic hydrocarbons contributes carbon atoms when burnt. In the refinery, aromatic
hydrocarbons are removed by extraction to a desirable extent so that the smoke point
becomes greater or near 20 mm. [ref 3]
5.2 Reference
[Ref 1] Manual on Hydrocarbon Analysis book, Page 263
[Ref 2] https://www.dno.no/annual-reports/dno-annual-report-2011/business-
units1/the-kurdistan-region-of-iraq/
[Ref 3] Refining Processes Handbook, Page 38