Refinery & PetrochemicalDrainage Solutions

SPCC (Spill Prevention, Control, and Countermeasure) regulations under 40 CFR 112 require secondary containment for petroleum storage and handling areas. Containment must equal 110% of the largest tank or 10% of total storage volume. Drainage must prevent discharge to navigable waters, typically requiring oil-water separators and containment sumps with manual release controls.

Fiberglass reinforced plastic (FRP), high-density polyethylene (HDPE), and 316L stainless steel are most common. FRP resists most petroleum products and many chemicals. HDPE handles hydrocarbons well and is economical. Stainless steel provides excellent corrosion resistance and high-temperature tolerance. Material selection depends on specific chemicals, temperatures, and load requirements.

Drainage in classified hazardous locations must meet electrical classification requirements. While drains themselves are passive, any electrical components (level sensors, heated drains, monitoring equipment) must be rated for the area classification (Class I, Division 1 or 2). Floor drains and trenches should be designed to prevent vapor accumulation in confined spaces.

Process unit drainage typically flows to contained areas with oil-water separators before treatment. Fire water drainage requires high-capacity systems for emergency scenarios. Cooling tower blowdown needs separate handling. Each process area should have isolation capability to contain spills. Trenches should slope toward collection points away from equipment.

Fire water drainage must handle the maximum credible fire scenario, often calculated based on equipment inventories and foam application rates. Systems should manage several thousand GPM for large equipment fires. Drainage routes to containment, not to storm sewers. Many facilities use fire water retention ponds sized for multi-hour incidents plus firefighting water.

Oil-water separators use gravity separation, coalescing plates, or both to remove hydrocarbons from water. API separators follow API 421 design standards for refinery applications. Proper sizing considers flow rates, hydrocarbon loading, and effluent requirements. Separators require regular maintenance and oil removal to maintain efficiency.

Tank farms require secondary containment berms with contained drainage. Drain valves must be normally closed with manual operation after verification of no product release. Containment drainage leads to oil-water separation, not direct discharge. Stormwater management must account for large impervious areas within containment.

Loading racks need containment for worst-case spill scenarios (full tank car or truck). Drainage flows to contained sumps with oil-water separation. Drip pans capture routine drips during connections. Emergency containment exceeds maximum single-event spill volume. Quick-closing isolation valves prevent contamination spread.

Regular inspection of containment integrity, valve operation, and separator efficiency is essential. Oil-water separators need oil removal and cleaning. Drain valve operability testing ensures emergency functionality. Trench and drain cleaning prevents sediment accumulation. SPCC plans require documented inspection schedules.

Refinery stormwater requires NPDES permits and is typically treated before discharge. Process areas drain to treatment systems, not storm sewers. Clean areas can drain to stormwater systems with appropriate monitoring. First-flush diversion captures initially contaminated runoff. Oil sheen monitoring prevents permit violations.