Raffinate (Aromatics Extraction Unit Paraffinic Byproduct) Storage — Paraffinic / Naphthenic Non-Aromatic Stream Tank Selection

Storing Raffinate? Start Here

Raffinate is a byproduct from the aromatics extraction process in refineries. It’s a paraffinic and naphthenic light hydrocarbon stream, often used as a feedstock in petrochemical complexes for producing ethylene and propylene or as a solvent. When considering storage options, it’s crucial to understand that raffinate is a low-aromatic, low-sulfur, and low-olefin stream, making it a versatile yet specific material to handle.

Can you store it in a poly tank?

No, raffinate should not be stored in polyethylene tanks. Polyethylene, whether HDPE or XLPE, is not suitable because it can swell and soften when in contact with raffinate. Instead, carbon steel tanks, as per API 650 standards, are recommended for safe storage.

Key Issue: Temperature Sensitivity

Raffinate has a low flash point and pour point, making it sensitive to temperature changes. It’s essential to store it in tanks that can maintain stable temperatures to prevent volatility and ensure safety. Floating-roof or internal-floating-roof tanks are often used to manage vapor pressure effectively.

The safety that actually matters

• Use carbon steel tanks with appropriate coatings to prevent corrosion.
• Ensure tanks have floating roofs to manage vapor pressures safely.
• Use Viton or FFKM gaskets for secure sealing in valves and pumps.

Common questions

What materials are suitable for storing raffinate?

Carbon steel with epoxy-novolac coatings is ideal, along with stainless steel for piping and trim.

Can raffinate be stored in plastic tanks?

No, polyethylene and FRP tanks are not suitable due to hydrocarbon attack.

What gaskets should be used?

Viton or FFKM gaskets are recommended for their resistance to hydrocarbons.