Date post: | 04-Jun-2018 |
Category: |
Documents |
Upload: | ocireg-ocireg |
View: | 238 times |
Download: | 3 times |
of 34
8/13/2019 4. Carbon Residue Test
1/34
4. Carbon Residue Test
(Experiment No. 3)
1
8/13/2019 4. Carbon Residue Test
2/34
1. OBJECTIVES:
1) To be able to determine the carbon residueof a liquid fuel.
2) To be able to know the definition of a
carbon residue test. 3) To be able to have knowledge about carbon
residue of a liquid fuel.
2
8/13/2019 4. Carbon Residue Test
3/34
2. THEORY AND
HYPOTHESIS: Carbon residue for a fossil fuel can be defined
as the tendency of that fuel to form carbon
deposits at high temperature in an inert
atmosphere.
Carbon residue for a fuel is measured in weight
percentage (wt %) or parts per million by
weight (ppm wt). High carbon residue value is
undesirable for a fuel.
3
8/13/2019 4. Carbon Residue Test
4/34
2. THEORY AND
HYPOTHESIS: (cont..) When oil is heated to a high temperature in the
absence of sufficient air a portion of the oil will
distill, thus leaving a carbon residue.
The amount of this residue is an index to theextent the oil is likely to decompose in service.
Under engine-operating conditions, the amount
and type of the carbon formed has an
important effect upon the performance of theengine.
4
8/13/2019 4. Carbon Residue Test
5/34
2. THEORY AND
HYPOTHESIS: (cont..) While no maximum residue specifications for
lubricating oils are commonly given, a relatively
smaller amount in one oil compared with
another should be favorable.
5
8/13/2019 4. Carbon Residue Test
6/34
2. THEORY AND
HYPOTHESIS: (cont..) Apparatus known as the Conradson carbon-
residue tester is widely used in this country.
It consist of a porcelain crucible with a
Skidmore iron crucible resting upon a layer ofsand in a second larger iron crucible, all of
which are supported upon a wire triangle on a
metal stand of specified dimensions.
6
8/13/2019 4. Carbon Residue Test
7/34
2. THEORY AND
HYPOTHESIS: (cont..) The assembled tester is shown in the figure.
The crucibles are surrounded by an asbestos
block and covered by a sheet-iron hood and
chimney.
Heat is applied by a Meker burner. An analytical
balance is used to weigh the sample of oil and
the residue.
7
8/13/2019 4. Carbon Residue Test
8/34
2. THEORY AND
HYPOTHESIS: (cont..)
8
8/13/2019 4. Carbon Residue Test
9/34
2. THEORY AND
HYPOTHESIS: (cont..) A clean porcelain crucible is weighed to the
nearest 5mg, then filled with a 10g sample of oil
and weighed to the same accuracy.
The crucible is then placed in a Skidmorecrucible.
The sand in the large iron crucible is leveled,
and the Skidmore crucibles are covered, and
the assembly of crucibles is centered on a wiretriangle with the asbestos insulation on a
suitable ring stand.
9
8/13/2019 4. Carbon Residue Test
10/34
2. THEORY AND
HYPOTHESIS: (cont..) The whole is covered with the sheet-iron hood,
and heat is applied with a strong flame from the
Meker burner so that the pre ignition period
will be from 8.5 to 11.5 min.
When smoke appears from the chimney, the
burner is moved or tilted so that the flame
passes up one side of the crucible and ignites
the oil vapor.
10
8/13/2019 4. Carbon Residue Test
11/34
2. THEORY AND
HYPOTHESIS: (cont..) The burner is momentarily removed and the
gas flame adjusted so that the vapors burn
uniformly with the high flame above the
chimney but not above the bridge on top of the
chimney.
The burning period should be from 12 to 14
min.
11
8/13/2019 4. Carbon Residue Test
12/34
2. THEORY AND
HYPOTHESIS: (cont..) When the burning and smoking have ceased,
the burner is adjusted so that the bottom of the
iron crucible is heated to a cherry red for
exactly 7 min.
The total period of heating should be 28 to 32
min. The burner is then removed and the
apparatus is allowed to cool for about 15 min.
12
8/13/2019 4. Carbon Residue Test
13/34
2. THEORY AND
HYPOTHESIS: (cont..) The porcelain crucible and contents are
reweighed, and the percentage of carbon
residue is calculated on the basis of the original
sample weight.
13
8/13/2019 4. Carbon Residue Test
14/34
2. THEORY AND
HYPOTHESIS: (cont..) The Conradson Test for the amount of carbon
in oil is accurate if test is properly performed.
Also through the experiment it was found out
that Carison residue is very small compared tothe amount of other components in oil.
Carbon residue test determine the percentage
of carbon that remains in a sample after the
volatile vapors had been driven off by heat.
14
8/13/2019 4. Carbon Residue Test
15/34
3. LIST OF APPARATUS:
1) Meker Bunsen Burner
15
8/13/2019 4. Carbon Residue Test
16/34
3. LIST OF APPARATUS:
(cont..) 2) Hood Porcelain Crucible
16
8/13/2019 4. Carbon Residue Test
17/34
3. LIST OF APPARATUS:
(cont..) 3) Tripod
17
8/13/2019 4. Carbon Residue Test
18/34
3. LIST OF APPARATUS:
(cont..) 4) Wire Mesh
18
8/13/2019 4. Carbon Residue Test
19/34
3. LIST OF APPARATUS:
(cont..) 5) Chimney
19
8/13/2019 4. Carbon Residue Test
20/34
4. SET UP OF
APPARATUS:
20
8/13/2019 4. Carbon Residue Test
21/34
5. PROCEDURES:
1) Place the two glass bends provided whichare about 1 in diameter in the porcelain
crucible and include their weight in the net
weight of the crucible. Then, add 10 grams of
the oil to be tested accurately weighed and free
from impurities.
21
8/13/2019 4. Carbon Residue Test
22/34
5. PROCEDURES: (cont..)
2) Place the crucible in the center of theSkidmore crucible. Level the sand in the sheet-
iron crucible and set the Skidmore crucible as it
is in the exact center of the iron crucible.
22
8/13/2019 4. Carbon Residue Test
23/34
5. PROCEDURES: (cont..)
3) Apply the covers to both the Skidmore andthe iron crucible, the one to the later fitting
loosely to allow exit of vapors that are formed.
23
8/13/2019 4. Carbon Residue Test
24/34
5. PROCEDURES: (cont..)
4) Place the bare nichrome wire triangle onthe metal tripod on the asbestos block as
hollow sheet metal box.
Center the short iron crucible into the block
with its bottom resting on top of the triangle
and cover the whole with the sheet iron hood in
order to distribute the heat during the process.
24
8/13/2019 4. Carbon Residue Test
25/34
5. PROCEDURES: (cont..)
5) Apply heat with a highly strong flame from aMeker type gas burner so that the pre ignition
period will be 10 and 1 1/2 minutes.
When some smoke appear above the chimney,
immediately move or tilt the burner so that the
gas flame plays on the sides of the crucible for
the purpose of igniting the vapors.
25
8/13/2019 4. Carbon Residue Test
26/34
5. PROCEDURES: (cont..)
Then, remove the heat temporarily and beforereplacing adjust the gas flame so that the
ignited vapors burn uniformly with the flame
above the chimney, but not above the wire
bridge.
Heat may be increased if necessary, when the
flame does not show above the chimney. The
period of burning the vapors shall be 13 and 1minutes.
26
8/13/2019 4. Carbon Residue Test
27/34
5. PROCEDURES: (cont..)
6) When the vapors cease to burn and nofurther blue smoke can be seen, readjust the
burner to hold the heat as in the beginning so
as to make the bottom, and the cover part of
the sheet-iron crucible, red and maintain for
exactly 7 minutes.
The total period of heating should be 2 to 30
minutes, which constitute an additionallimitation on the tolerances for the preignition
and burning periods.
27
8/13/2019 4. Carbon Residue Test
28/34
5. PROCEDURES: (cont..)
7) There should be no difficulty in carrying outthe test exactly or directed with the gas burner
provided, using city gas with the top of the
burner about 2 below the bottom of the
crucible. The time periods should be observed
with whatever burner or gas used.
28
8/13/2019 4. Carbon Residue Test
29/34
5. PROCEDURES: (cont..)
8) Remove the burner and allow the apparatusto cool until no smoke appears, then remove
the cover of the Skidmore crucible. Remove the
porcelain crucible with heated tongs, place in
the dessicator, cool and weigh.
29
8/13/2019 4. Carbon Residue Test
30/34
5. PROCEDURES: (cont..)
9) The total weight of the crucible plus beadsand 10 grams of oil at start minus the weight of
the crucible plus beads and carbon residue at
finish equals loss of oil on grams.
The 10 grams of oil minus loss in weight of oil
equals carbon residue in grams, divided by 10
grams equals % of carbon residue.
30
8/13/2019 4. Carbon Residue Test
31/34
5. PROCEDURES: (cont..)
31
%% 100oilofweight
residuecarbonofweightresiduecarbonof
crucibleofwtresiduecarbonandcrucibleofwtresidueofwt ...
%.&.
.&.% 100
crucibleofwtoilcrucibleofwt
crucibleofwtresiduecrucibleofwtresiduecarbon
8/13/2019 4. Carbon Residue Test
32/34
6. DATA & RESULTS:
Weight of crucible = _______________
Weight of oil = ___________________
% of carbon residue = ______________
Weight of carbon residue = __________
3
2
8/13/2019 4. Carbon Residue Test
33/34
7. SAMPLE COMPUTATIONS:
8. QUESTIONS :
9. ANSWERS:
10. DISCUSSION: 11. CONCLUSION/RECOMMENDATION:
12. REFERENCES:
33
8/13/2019 4. Carbon Residue Test
34/34
END