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Maintenance Section Fuel Specifications
Modifying the Pour Point
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Cloud point of fuel mixtures |
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Generally, the most practical method that is used to prevent problems that are caused by fuel cloud point at low temperatures is the use of fuel heaters. In most applications, fuel heaters can be used at a lower cost than fuel mixtures.
Pour PointThe fuel’s pour point is a temperature below the fuel’s cloud point. Fuel stops flowing below the pour point. The pour point is the temperature which limits movement of the fuel with pumps.
To measure the pour point, the fuel temperature is lowered below the cloud point in steps of 3C (5F) at a time. The temperature is lowered until the fuel does not flow. The pour point is the last temperature that is shown before the flow stops.
At the pour point, the wax has solidified out of the fuel. This makes the fuel more solid than liquid. The pour point of the fuel can be improved. This does not require the removal of important elements. This process is the same process that is used to improve the cloud point of a fuel.
A fuel’s pour point should be at least 6C (10F) below the lowest ambient temperature that is required for engine
You can lower the fuel’s pour point by using additives. You can also lower the pour point by mixing the fuel with a fuel that has a lower pour point. See the topic “Cloud Point” for the procedure. This procedure is not the best procedure to use.
The same table that was use for cloud point can be used for an estimate of pour points. This is true only if the fuels do not have additives which change the pour point.
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Cloud point of fuel mixtures |
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In order to calculate the amount of lighter fuel that is required to be blended with the heavier fuel, perform the following steps:
1.Obtain the specification for fuel cloud point of both fuels from your fuel supplier.
2.Locate the cloud point of the heavier fuel on the left side of the table. Mark the point on the table.
3.Locate the cloud point of the lighter fuel on the right side of the table. Mark the point on the table.
4.Draw a line between the two points that were established. Label this line “A”.