Conradson carbon residue, commonly known as "Concarbon" or "CCR", is a laboratory test used to provide an indication of the coke-forming tendencies of an oil.
Quantitatively, the test measures the amount of carbonaceous residue remaining after the oil's evaporation and pyrolysis.
[1][2][3] In general, the test is applicable to petroleum products which are relatively non-volatile, and which decompose on distillation at atmospheric pressure.
[4] The phrase "Conradson carbon residue" and its common names can refer to either the test or the numerical value obtained from it.
During a fixed period of severe heating, the residue undergoes cracking and coking reactions .