Vacuum Gas Oil (VGO) Storage & Tank Compatibility

Storing Vacuum Gas Oil (VGO)? Start Here

Vacuum gas oil (VGO) is a heavy intermediate refinery stream — the fraction recovered when the residue from atmospheric distillation is re-distilled under vacuum. It is a complex mixture of large C20–C45 saturated and aromatic hydrocarbons with a boiling range of roughly 370–565°C (700–1050°F), carrying sulfur, nitrogen, and (in coker VGO) trace metals that vary with the crude source. VGO is not a finished fuel; it is a feedstock for fluid catalytic cracking, hydrocracking, and coking, which break it into gasoline, diesel, jet fuel, and petrochemical feeds.

Because VGO is a viscous, aromatic, non-aqueous hydrocarbon handled warm to stay pumpable, the dominant material-of-construction driver is hydrocarbon compatibility and temperature, not pH. Aromatic hydrocarbons absorb into and swell polyolefins, so the correct container is heat-traced steel — the same logic API 650 and UL-142 petroleum-tank practice is built around. Getting the material wrong risks wall softening, permeation, and an environmental release.

Polyethylene (HDPE / XLPE) Compatibility with Vacuum Gas Oil

Verdict: Unsuitable (U). Polyethylene tanks are not recommended for storing vacuum gas oil or any heavy petroleum stream. VGO is a non-aqueous hydrocarbon mixture rich in polycyclic aromatics, and aromatic hydrocarbons are among the worst offenders for polyethylene — published HDPE/LDPE resistance charts rate fuel oils and aromatic hydrocarbons as marginal-to-not-recommended even at ambient temperature, with resistance collapsing as temperature rises. Because VGO is handled warm to keep it pumpable, this is exactly the high-absorption regime poly cannot tolerate: the wall swells and softens, loses strength, weeps, and becomes prone to environmental stress cracking, and hydrocarbon vapor permeates the wall over time.

Just as importantly, heavy petroleum and combustible-liquid storage is governed by steel-tank practice (API 650 for large field-erected tanks, UL-142 for shop-built aboveground tanks) — polyethylene tanks are not listed for this service. Use heat-traced, insulated steel, or a fuel-grade FRP tank only where its resin and temperature rating are confirmed for hot, aromatic service.

Material compatibility at a glance

Store vacuum gas oil in steel (API 650 / UL-142) — typically heat-traced and insulated to keep it pumpable — not in polyethylene. VGO is a heavy, aromatic, non-aqueous hydrocarbon that absorbs into and swells poly, so HDPE/XLPE is unsuitable. FRP is conditional on a hydrocarbon-resistant resin and its temperature rating. Pair steel with Viton (FKM) seals; treat nitrile as conditional and avoid EPDM.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Aspiration hazard: H304 — may be fatal if swallowed and it enters the airways; never siphon by mouth; do not induce vomiting.
• Carcinogen / organ effects: H350 and H373 — heavy refinery streams can contain carcinogenic polycyclic aromatics; minimize skin contact and inhalation; prolonged/repeated exposure can damage organs.
• Skin & inhalation irritant: H315 and H332 — wear chemical-resistant gloves and eye protection; ensure adequate ventilation; harmful if inhaled.
• Hot-handling burn risk: VGO is stored and pumped warm to stay fluid; surfaces, lines, and product can cause thermal burns — use insulation, guarding, and PPE.
• Combustible liquid: high flash point but will burn; keep away from heat, open flame, and hot surfaces; bond and ground during transfer.
• Environmental hazard: H411 — toxic to aquatic life with long-lasting effects; provide secondary containment and prevent releases to soil and water.

Common questions

Can I store vacuum gas oil in a polyethylene (HDPE or XLPE) tank?

No. Polyethylene is unsuitable for heavy petroleum storage. VGO is an aromatic-rich hydrocarbon that absorbs into and swells poly, causing softening, weeping, permeation, and stress cracking — and because VGO is handled warm, these effects are accelerated. Resistance charts rate fuel oils and aromatic hydrocarbons as marginal-to-not-recommended for HDPE, and poly tanks are not listed for petroleum service. Use heat-traced steel.

What tank material should I use for VGO storage?

Steel is the industry standard: API 650 for large field-erected tanks and UL-142 for shop-built aboveground tanks, typically heat-traced and insulated to keep the oil pumpable. Stainless adds corrosion margin for higher-sulfur or hot service. Fuel-grade FRP is only acceptable with a confirmed hydrocarbon-resistant resin within its temperature rating.

Does vacuum gas oil have a pH that matters for tank selection?

No — VGO is a non-aqueous hydrocarbon, so pH is not the deciding factor. The dominant compatibility drivers are hydrocarbon (especially aromatic) resistance and the warm handling temperature. The material must not absorb or swell in petroleum at elevated temperature, which is why steel is specified rather than plastics.

Why does VGO need heated or insulated storage?

VGO is a heavy, viscous fraction that becomes very thick or near-solid when cool, so it is stored and transferred warm using heat tracing and insulation to stay pumpable. That warm service is also why polyethylene fails faster here — hydrocarbon absorption and swelling in poly worsen sharply with temperature.