1. Jet A – Thermal Oxidation Test Training Memphis Refinery Lab
JTOT
Jet A – Thermal Oxidation Test
Training
Memphis Refinery Lab
11/19/2018

2. Purpose for JTOT
The Jet Fuel Thermal Oxidation Tester JTOT has been designed to produce an accelerated (higher temperature) version of conditions that might be experienced by a fuel flowing through a typical engine system.
The test measures the high temperature stability of gas turbine fuels to ensure the Jet fuel meets the quality standards for temperature stability and deposit decomposition products within the fuel system.
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3. Purpose for JTOT
During the test, fuel is pumped at a fixed volumetric flow rate through a heater, after which it enters a precision stainless steel filter where fuel degradation products may become trapped.
For example, Commercial Jet fuels must be found to be thermally stable at a fuel temperature as high as 163oC (325oF).
The Fuel is rated by measuring:
Pressure drop (mm Hg)
Tube deposits.
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4. Safety PPE
The operator must comply with all Valero Safety standards and be appropriately dressed with the following:
Fire Resistant (FRE) Lab Coat
Safety Glasses with Side Shields
Solvent Resistant Gloves
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5. Equipment Required
The equipment required for assembling and operating the Jet TOT includes:
1000 ml graduated cylinder
Allen Screwdriver (#38016)
Nut driver (#38015)
Piston Puller (#38087)
A 9/16ths open-end wrench is not essential but helpful for insuring secure fittings
1000 ml beaker (#17643)
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6. Equipment Required
Insert video
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7. Tools and Equipment Piston Puller 1000 ml Graduated Cylinder
1000 ml Beaker
9/16” Wrench
Allen Screwdriver
Nut Driver
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8. Materials Required
Prior to beginning the test, you must ensure you also have the following:
Jet A Sample
Appropriate Filters
Sample Filters
Differential Filter
Pre-Filter
Appropriate O-Rings
Heater Tube
Appropriate Insulators
Distilled Water
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9. Pre-Assembly
Several equipment components must be inspected and pre-assembled for each Jet TOT. These include:
Trap Assembly
Fuel Reservoir Assembly
Filter Funnel Holder Assembly
Heater Assembly
Pre-Filter Assembly
Water Reservoir Assembly
Heater Tube Assembly
Filter Section Assembly
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10. Pre-Assembly
Remember that new components (heater assembly, o-rings, and filters) are required for each new test. DO NOT REUSE!
Assembly of each component will now be discussed.
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11. Trap Assembly
This is the trap, it will be filled with distilled water.
This is the distilled water reservoir, this is the top to it.
Notice it has an O-ring.
This will hold the distilled water.
These are the six nuts with washers that are used to assemble the top to the O-ring.
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12. Fuel Reservoir Assembly
This is the fuel reservoir.
It’s a piston cylinder.
Notice it also has an O-ring.
Notice that the bottom of the piston is flush with the bottom of the cylinder at the start of the test.
That’s the cap.
That’s the stand that holds the Fuel reservoir.
This is the filter funnel holder.
It attaches to the top of the fuel reservoir when we are ready to filter our sample into the container.
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13. Heater Assembly This is the heater assembly, with the insulators.
And the nuts that hold the insulators and o-rings in place.
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14. Pre-Filter Assembly This is the pre-filter assembly.
Notice it also has an o-ring.
It has three nuts that assemble the two pieces.
A new 0.45 um millipore filter is installed in it.
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15. Water Reservoir Assembly
Filling and assembling the water reservoir.
The water reservoir should be clean.
The rings should be in place in the groove. You may need to press the o-ring into the groove with your finger.
We are going to fill it with distilled water. Be sure to fill it completely to the top of the reservoir.
Install the nuts. Ensure they have the washer on prior to assembly otherwise it’s difficult to take apart later on.
Finger tighten all the nuts in a crisscross pattern to secure the lid evenly.
You want to go across then skip one.
Then go back across, then the next one.
Now tighten the nuts with the nut-driver in the same crisscross pattern. Do not overtighten.
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16. Fuel Reservoir Assembly
Make sure that the o-ring is intact.
You want to feel and make sure that there is no foreign matter on the o-ring surface that could cause the seal to fail.
Also ensure the o-ring is secured in the grove at the bottom of the Reservoir.
The piston must be level with the bottom of the Fuel Reservoir. Be careful not to pull the piston out of the cylinder.
When you place the cylinder in the assembly stand, it will press it up to the proper level.
The filter/aeration funnel screws on the top of the Fuel Reservoir in a clockwise rotation.
You are ready to put the filter paper in.
You are now ready to add the sample through the filter into the Fuel Reservoir.
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17. Heater Tube
Another consumable item that we use is going to be the standard heater tube.
It’s a polished aluminum tube made to the exact specifications of the specified materials, we’ll look at those later on.
The tube kit come with the tube. Inside the tube kit is the differential pressure filter, with a red dot on it and three o-rings.
The heater tube has a hole in one end and the other end it solid.
The end with the hole in it is where the probe is going to be.
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18. Heater Tube Assembly
During the assembly it is essential that you wear gloves.
Holding the heater tube at one end, carefully insert it into the heater tube housing. Note that the open end of the heater tube must be oriented up to permit thermocouple insertion (the other end is plugged.)
There are four ceramic insulators.
The one with the small collar goes in first, then an o-ring goes on top of that.
Then a large collar. (reverse Oreo – white/black/white)
Place the nut on top to lock them in. (finger tight only) When properly installed you will see the white of the last insulator protruding through the nut.
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19. Heater Tube Assembly Repeat the process on the bottom side.
Observe the heater tube through the fuel discharge hole.
You should be able to see the holder bisecting the entrance of the tube.
Once everything is in position, tighten down the nuts on both ends securely.
Confirm that the shoulder of the rod is still in place.
Insert the filter with the red side up.
Place the 3rd o-ring on top of the filter.
The heater tube section is now completely assembled.
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20. Filter Section Assembly
You’ll notice that the Millipore filters are packed with one white Millipore filter sandwiched in between two blue guard membranes.
You do not want to get the guard membranes into the filter section or the test will fail.
Double check to make sure that you do not have the guard membrane on your filter.
Ensure the metal backup screen is in place –
Place the Millipore filter against the metal backup screen.
Check to make sure the o-ring is in place and clean.
Assemble the two housing pieces, insert the 3 screws and tighten with the nut driver.
Connect the pre-filter assembly to the reservoir cover and finger tighten.
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21. Filling the water trap.
Fill the water Trap with Distilled water at least to the shoulder.
Attach the glass jar to the air trap assembly and place a beaker under the air trap assembly drip line.
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22. Testing
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23. Pre Test Checks Make sure you have that in the right place.
Tighten it up.
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24. Initiate Test Aeration Finish Assembly Start Sample Cylinder Purge
Aeration now finished, you are going to blow out the tube.
Finish Assembly
Start Sample Cylinder Purge
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25. Start Test See the pressure is going up.
Now is a good time to observe if you have any leaks. If any leaks are noted, tighten connections immediately.
Note – if the pressure is not going up – there is probably a leak so re-check.
When the pressure reaches about 500 psig, the Jet-TOT will automatically:
Turn the heater power to ON at 80% initial power
Record the time that the heater turned on
Increase the temperature to the specified Set Point
Begin counting down the Test Timer
When the pressure stabilizes – the Jet-TOT will automatically “Tare” to “0” and a large “T” will appear on the screen.
The test will now run automatically and finish in about an hour and 49 minutes.
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26. Shut Down and Clean-up
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