Spent caustic is a sodium hydroxide solution that has been used up in washing acidic components out of hydrocarbon streams. It is a common waste stream in refineries and petrochemical plants, and it needs proper handling.
Where It Comes From
Caustic scrubbers remove hydrogen sulfide, mercaptans and carbon dioxide from gas and liquid streams such as LPG, gasoline and ethylene. When the caustic is exhausted, it is drawn off as spent caustic.
What It Contains
- Sulfides and mercaptans, which give it a strong odor
- Phenols and organic acids, depending on the source
- Dissolved hydrocarbons, sometimes including BTEX
- High COD and high alkalinity
How It Is Treated
Treatment depends on the type of spent caustic and the plant’s goal. Typical routes include removing hydrocarbons and BTEX first, neutralizing and oxidizing the sulfur compounds, and recovering caustic or salts where it is worthwhile. In petrochemical wastewater, recovering caustic and useful salts reduces how much has to be treated or disposed of. Hauling it off site is costly and adds transport risk, so on-site treatment is often preferred.
Using Mobile Units
Rental skid-mounted units let plants treat spent caustic without capital spending, for example during turnarounds or upsets. Power Energy supplies these as rental, rent-to-own or operated units. See spent caustic treatment and mobile treatment units.
Talk to Power Energy
Send us your stream details, contaminants and flow rate. Call or WhatsApp +966 56 278 9535 or email sales@powerenergy.com.co.