Stabilizer for Unstable Cracked Streams
In refineries the most commonly used cracked streams for blending in the HSD pool are either from FCCU (i.e. LCO) or DCU (i.e. LGO, Coker, Kero). As a result of the cracking process, these streams contain a larger concentration of unsaturated hydrocarbons.
Oxidation of unsaturated hydrocarbons along with reaction with heteroatomic impurities results in the formation of unwanted gums, sludge and other insoluble materials resulting in unstable finished products. Refiners commonly adopt hydro treating solution to enhance the storage stability of these cracked streams. However, hydro treating is an expensive option.
Alternatively chemical stabilizers / antioxidants are used to improve stability of unstable cracked steams. This gives the flexibility to the refiner to use the available hydro treating capacity to de-sulfurize the diesel. Hence, a chemical treatment is a cost effective solution vs. hydro treating.
CRISTOL AO-473 is a ester consisting of a long and branched chain of alkyl, hydroxyl, carbohydroxy substituted alkyl and phenyl group which are useful in stabilizing fuel oil formulations for preventing colour change and sludge deposition due to oxidative degradation resulting from atmospheric heat and oxygen. CRISTOL AO-473 is recommended to be used @10 – 150 ppm.