Effluent and pretreatment set up

Usual discharge standards applied to French refineries are supplemented here by a local government decree dating back to 1988. It lays down daily or monthly average figures for a number of parameters. 

Phenolic spent caustic amounting to about 1500 m -y is redistributed in rhe crude downstream from the desalter depending on further treatment of the crude (visbreaker). Refinery sulfidic spent caustic of a similar volume is disposed of outside the refinery. 

Process water (copping, FCC, etc. condensates) undergoes steam stripping. Efficiency has been enhanced so thatNH elimination has reached 50 rngd .  

The sour hot effluents for the naphthenic acids unit are cooled down by being mixed with other condensates and industrial water and then deoiled still at an acid pH. Then they are collected together and self-neutralized with the general stream which is slightly alkaline (pH 9). 

The effluents from the north of the plant (FCC, paved areas, etc.) and from the lube oil complex undergo preliminary two-stage oil removal (CPI and API) before they are pumped to the general storage tank. 

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