[Aqualectra]

Dear readers,

I work as a Mechanical Engineer at a diesel powerplant and we are confronting some problems with excessive wear of Fuel pump plungers.
Several tests has been done to the FUEL Oil and everything came positive according to the Fuel specs.
Looking at the system itself I became interested in the Chemical Reaction of some components in fuel which cannot be affected by the separator.

These components are MCR, Sulphur, Vanadium, Asphaltenes, Nickel, CCAI,Viscosity and Density.
Since the problem concentrates in the Fuel Pump the viscosity of HFO must be 16mm2/s
at approx 122degrees.

I want to know at temperatures between 122 and 130degrees if there is another chemical reaction taking place between Vanadium, Sulphur, Asphaltenes and Nickel in severe way that it could affect the Fuel Pump Plunger.( compress of Fuel)

Some thought I have by means of chemical reaction:
-A lowering in melting point (Flashpoint)
-Chemical reaction which could work the same as Cat Fines which obviously is unwanted in mechanical driving components. Therefore they are separated from the Fuel Oil in the separator

I hope anyone can explain if there is such a reaction taking place or not.
Thanks before hand.

[eugenedakin]

Hello Aqualectra,

The good and bad news is that there are many reactions that can take place with these products to cause a 'gum' of sorts to form and be harmful to plungers in a Fuel Pump Plunger. My guess is that the higher temperatures of a plunger and the reduction in pressure is causing some lower-boiling-point products to flash or boil off, leaving behind traces of residue each time this occurs. This phenomenon will typically happen over a period of weeks or months.

One of many ways to lower the possibility of this from occurring is by implementing good filtration (at the pumps and in-line filters on the diesel powerplant). A graduated filter system (larger filters then down to smaller filter pore sizes) will usually quickly trap you problem. If filters are continually plugging, then switch diesel suppliers, as you are getting too many fractioning 'bottoms' which are causing problems.

There are many other problems that can occur. If you have further thoughts, feel free to share them and I will help out where I can.

Best wishes,

Eugene

[Aqualectra]

Eugene

Thank you for the reaction given on this matter.

Can this chemical reaction be given in a calculation if you know some values of the unseparated components? (Micro Carbon Residual, Sulphur, Vanadium, Asphaltenes, Nickel, CCAI,Viscosity and Density)

Considering to take some assumption:
-If separation of sediments does not happend 100%
-If separation occurs 100%

[eugenedakin]

Hello Aqualectra,

Unfortunately, the chemical reactions can quickly become overwhelming. To make this even more complicated, there is no single formula for asphaltene. To find out more about this chemical, feel free to review http://en.wikipedia.org/wiki/Asphaltene.

Each process and each chemical reaction will vary throughout the day and with each batch of raw ingredients. Sorry, chemistry is complicated.

Separation in the field will never happen at 100% - impurities will always exist. All you can do is chemically treat the 'major' factors and perform chemical testing from there. This could honestly be a research study.

I wish I could help out more.

Best wishes,

Eugene

[Aqualectra]

Hallo Eugene,

Don't worry you are helping me alot.
All the thoughts I have were true and became more clear on your explanation.

I have read the link about Asphaltene and I have some questions.

First of all some fractions of the encyclopedia

Asphaltenes consist primarily of carbon, hydrogen, nitrogen, oxygen, and sulfur, as well as trace amounts of VANADIUM and NICKEL

However, it is undisputed that the asphaltenes are composed mainly of polyaromatic carbon i.e. polycondensed aromatic benzene units with oxygen, nitrogen, and sulfur, (NSO-compounds) combined with minor amounts of a series of heavy metals, particularly VANADIUM and NICKEL which occur in porphyrin structures

Also that 100% separation never happen.

Can I assume that, the (small) amounts of the components Vanadium, Nickel, Micro Carbon Residual, Sulphur, Asphaltenes itself, can bind together or form a chemical reaction sufficient to wear down a plunger in a short period?

Also taking in consideration the high temperature (128 degrees) of the fuel for visco regulation and possible increase of temperature bymeans of compression of fuel in the Fuel Pump.

[eugenedakin]

Hello Aqualectra,

With your first question:

Can I assume that, the (small) amounts of the components Vanadium, Nickel, Micro Carbon Residual, Sulphur, Asphaltenes itself, can bind together or form a chemical reaction sufficient to wear down a plunger in a short period?

Yes, there is a very high probability that this is causing the plunger to wear down. When I used to perform mechanical work, this residue is commonly called 'varnish'. This is a way of saying 'polished fine material that is tenaciously stuck to the metal'.

I hope this helps you with a solution to your problem.

Best wishes,

Eugene