Cochin laboratory

ASH CONTENT (P 4, D 482, IP 4, ISO 6245)

SULFATED ASH (P 4, D 874, IP 163, ISO 3987)

Ash is the organic matter-free (or carbonaceous matter free) residue that remains after combustion of a fuel oil at a specified high temperature. This gives an idea about the ash forming impurities, mostly metallic or inorganic contaminant in the fuel. The ash-forming constituents in distillate fuel are typically so low that they do not adversely affect gas turbine performance, unless such corrosive species as sodium, potassium, lead, or vanadium are present. Ash in a petroleum product can result from oil or water soluble metallic compounds or from extraneous solids such as dirt and rust. Ash test method is not valid for petroleum products containing ash forming additives, including certain phosphorus compounds, or lubricating oils containing lead, or used engine crankcase oils. In certain distillate oils also all of the ash forming metals may not be quantitatively retained in the ash and in all such cases sulfated ash should be used.