Prueba para cenizas en productos petroleros.

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ASTM D 482 Standard Test Method for Ash from Petroleum
Products
Background
Scope (1.1)
• This test method addresses the procedure for determining the ash content from
petroleum products.
o in a range of 0.001 - 0.180 mass %
o applicable to distillate and residual fuels, gas turbine fuels, crude oils, lubricating
oils, waxes, and other petroleum products
Scope (1.1)
• Any ash-forming materials present in the petroleum products are normally considered
to be undesirable impurities or contaminants.
• This test method is limited to petroleum products having no added ash-forming
additives such as phosphorus compounds.
Summary of Test Method (3.1)
• The sample contained in a suitable vessel is ignited.
• The ignited sample is allowed to burn until only ash and carbon remain.
• The carbonaceous residue is heated in a muffle furnace at 775 °C, and reduced to
ash.
• The ash is cooled and weighed.
Significance and Use (4.1)
• Determining the ash content helps to decide whether or not the product is suitable for
use in a specified application.
o ash can result from oil or water-soluble metallic compounds or extraneous solids
such as dirt and rust
Apparatus
Apparatus (5)
• Evaporating Dish or Crucible
• Electric Muffle Furnace
• Meeker Gas Burner
• Mechanical Shaker
Evaporating Dish or Crucible (5.1)

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• Made of platinum, silica, or porcelain,
• Capacity of 90 -120 mL.
Electric Muffle Furnace (5.2)
• Capable of maintaining temperature of 775 ± 25 °C.
• Has apertures at front and rear to allow slow natural draught of air to pass through.
Reagents (6)
• Propan-2-ol
• Toluene
Quality Control (QC) Samples (6.3)
• Are portions of one or more stable and representative liquid petroleum materials.
Sampling (7)
• Obtain samples in accordance with ASTM Practice D 4057 or ASTM D 4177.
• Transfer the portion of the sample to the crucible,
o after ensuring that the portion taken is representative of the larger portion
• Shake the sample vigorously.
Procedure
Procedure (8.1)
• Heat the crucible at 700-800 °C for a minimum of 10 minutes.
• Cool the crucible to room temperature in a container.
• Weigh the crucible to the nearest 0.1 mg.
Procedure (8.2)
• Mix the sample thoroughly before weighing, when the sample is sufficiently mobile.
o satisfactory mixing can be achieved in 10 minutes by manual shaking or using a
mechanical shaker
• Examine the sample for homogeneity.
• Continue mixing the sample, if it is not homogeneous.
Procedure (8.2.1, 8.2.2)
• When the sample is not homogenized after repeated mixings,
o use a non-aerating, high-speed shear mixer as per ASTM D 4928
• When the sample cannot be satisfactorily homogenized,
o reject the sample and acquire a new sample
Procedure (8.2.3)

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• When the sample is viscous or solid at room temperature,
o heat the sample until the sample is entirely liquid and mix carefully
o an oven at an appropriate temperature can be used for heating
• Mix the sample carefully by stirring rather than shaking.
Procedure (8.3)
• Select the quantity of the test specimen based on the expected ash content, as
described in Table 1.
• Select the weighing procedure based on whether the sample requires heating or not,
and whether more than one portion has to be weighed.
Note 3
• The container can be a desiccator not containing a desiccating agent.
• All weighings of the crucible should be performed immediately after cooling the
crucible.
Table 1- Test Specimen Mass versus Ash Content
Expected Ash (mass %)
Test Specimen
Mass (g)
Ash Mass
(mg)
0.18 11 20
0.10 20 20
0.05 40 20
0.04 50 20
0.02 100 20
0.01 100 10
0.001 100 1
Procedure (8.4)
• Use a top loading balance to weigh the sufficient test specimen to the nearest 0.1 g
into the crucible.
o to yield no more than 20 mg of ash

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• Determine the mass of the test specimen at ambient temperature which is the
difference between the initial and final masses of the sample container weighed at
ambient temperatures.
Procedure (8.6)
• If one weighing is sufficient, carefully heat the crucible with the Meeker burner until
the contents are ignited by the flame.
• Maintain the crucible at the temperature sufficient to burn the sample at a uniform
and moderate rate.
o only the carbonaceous residue is left when the burning ceases
o use a hot plate for burning the sample
Procedure (8.6.1)
• The sample may contain water causing spattering effect.
o it is advisable for an operator to heat the sample cautiously by wearing personnel
protective equipment such as safety goggles and gloves
o discard the test portion when the sample escapes the confines of the crucible
due to severe spattering
Procedure (8.6.1)
• If the first test portion is discarded, add 2 ± 1 mL of flammable propan-2-ol to a
second test portion,
o while stirring the second test portion with a glass rod and warming it gently to
liquefy, if it is solid
• If this is unsuccessful, repeat the process on a third test portion using a 10 ± 1 mL
mixture of toluene and the propan-2-ol,
o each weighing 50 ± 5 % by volume
o take care since toluene is flammable and its vapor harmful
Procedure (8.6.1)
• Remove and transfer any test specimen adhering to the glass rod to the crucible
using a strip made of ashless filter paper.
• Continue burning the sample strictly under operator vigilance.
Procedure (8.8)
• Some test specimens will require extra heating after the burning has ceased.
o heavy samples such as marine fuels forming crusts over the unburned material
• The crust can be broken with the glass rod.
o remove and transfer the crust adhering on the glass rod to the crucible using the
strip

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• Burn the remaining test specimen.
Procedure (8.9)
• Avoid foaming of heavier material with considerable care.
• Avoid overheating to prevent a red hot appearance of the test specimen or the dish,
and loss of ash.
• Maintain the flame ignition level to be below the rim of the dish to avoid superheating
of the crust and sparks.
Procedure (8.10, 8.11)
• Heat the residue in the muffle furnace at 775 ± 25 °C until all carbonaceous material
has disappeared.
• Cool the dish to room temperature in the container and weigh to the nearest 0.1 mg.
• Reheat the dish for 20 min, cool and reweigh.
• Repeat the heating, cooling and weighing processes until consecutive weighings
differ by not more than 0.5 mg.
Note
• If more than one addition of test specimen is required, cool the dish to ambient
temperature before adding more samples.
Calculation
Calculation (9.1)
Calculate the mass of the ash as a percentage of the original samples using the formula,
mass % = (w/W)x100
Where,
w - mass of ash (in g)
W - mass of sample (in g)
Report (10)
• Record the value as the ash content, stating the mass of the sample taken.
Test Specimen Mass, g Report to
9.00 - 39.99 3 decimal places
≥ 40.00 3 - 4 decimal places

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Quality Control (QC)
• Confirm the performance of the instrument or the test procedure by analyzing the QC
sample.
• When QC/Quality Assurance (QA) protocols are already established in the testing
facility, confirm the reliability of the test result using the protocols.
• When there is no QC/QA protocol established in the testing facility, use Appendix X1
as described in the standard as the QC/QA system.
The End