- Gasoline Shelf Life

-Revised on 10th Mar 2017,  12th Mar 2018,

- Gasoline Shelf Life

Gasoline shelf life is a controversial issue. Expert give 3 to 6 months self life of Motor Gasoline.
One recommendation is to test the fuel sample to tests like Distillation, Existent Gum & RVP.

Due to aging, the fuel olefin hydrocarbons get polymerised to Gum, loosing few important properties. An offensive smell is also indication of very old gasoline.

Gasoline stored in fuel tanks, vehicle tanks and other containers will with time slowly oxidized and degrade into a sticky material called technically "Gums". Such gums will separate out from gasoline and stick to fuel lines and engine components resulting into inefficient power output.

Gasoline blended with oxygenetes like Ethanol reduces shelf life of gasoline. To reduce such deterioration, appropriate does of anti-oxidant is must when ethanol is blended in gasoline. 

Gasoline samples kept in proper airtight containers in laboratory conditions have been found with reproducible test results in many of key properties like Density, Distillation, Existent Gum, Benzene, Sulphur etc after 12 months sample testing.

In field, storage conditions like temperature, storage tank hygiene particularly presence of water, metal impurities, tank internal paintings etc will decide how many months the product is usable without any performance affected.

With time,  most volatile hydrocarbons of gasoline will also evaporate slowly resulting into lower vapor pressure.  Below certain vapor pressure vehicle engine will not start. 

Thus, it is always better to have vehicle tank refueled such that the gasoline will get completely exhausted not later than 3 months of filling.

Fuel specifications demand fuel stability for reasonable time.  Some anti oxidant additives delay gum formation and the same  recommended in most of the gasoline specifications.

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Comments

xyz said…
The use of antioxident become essential to increase self life.
xyz said…
What about Diesel Shelf Life
Anonymous said…
Sir, is it affect on RON test or not? I believe that, RON also decreases with time...
R J Patel said…
largely Yes, depends on going out evaporated hydrocarbons. ex. iso-butane, iso-pentane have very high RON compared to total RON of Gasoline.

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