Demulsifier (Polyglycol / Oxyalkylated Blend) Storage & Tank Compatibility

Storing Demulsifier (Polyglycol / Oxyalkylated Blend)? Start Here

A polyglycol demulsifier is a formulated oilfield emulsion breaker, not a single pure chemical. The active is typically an oxyalkylated polyglycol or polyalkylene-glycol ester — often paired with an oxyalkylated resin or block copolymer — dissolved in a carrier of aromatic solvent (xylene or heavy aromatic naphtha) plus lower alcohols. It is injected upstream of a separator or treater to coalesce and resolve water-in-oil (and oil-in-water) emulsions in crude production, dewatering, and desalting.

Although the polyglycol active itself is relatively benign, the finished product is dominated by its flammable solvent carrier. That carrier — not the surfactant — governs storage. Aromatic hydrocarbons attack polyethylene by swelling and permeation, so materials of construction must be chosen for the solvent, which is why this product belongs in steel, lined, or stainless tankage rather than common poly tanks.

Can You Store Polyglycol Demulsifier in a Poly (HDPE / XLPE) Tank?

No — not recommended. The active polyglycol component would be fine in polyethylene, but commercial demulsifiers are blended into an aromatic-solvent carrier (xylene, heavy aromatic naphtha) with alcohol co-solvents. Published polyethylene resistance data rate aromatic hydrocarbons such as xylene, toluene, and benzene as Unsatisfactory for HDPE at both ambient and elevated temperatures, where swelling, softening, and permeation become a problem. The product is also a flammable liquid, which favors UL-142 steel tankage. Use carbon steel (lined or UL-142), 304/316 stainless, or a properly specified solvent-resistant FRP — with bonding, grounding, and ventilation. Always verify the materials section against the supplier SDS for the exact formulation, since solvent ratios vary by product.

Material compatibility at a glance

Treat this as a flammable, solvent-borne product, not an aqueous chemical. The aromatic-hydrocarbon and alcohol carrier — not the polyglycol active — sets the materials of construction. Store in UL-142 steel or lined/stainless tankage with bonding, grounding, and proper ventilation. Polyethylene (HDPE/XLPE) and polypropylene are unsuitable because aromatics permeate and swell them.

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

• Flammable liquid and vapor (H226) — keep away from heat, sparks, open flames, and hot surfaces; no smoking. Vapors can travel to an ignition source.
• Aspiration hazard (H304) — may be fatal if swallowed and drawn into the lungs; do not induce vomiting.
• Skin and eye irritation (H315 / H319) — wear chemical-resistant gloves and splash goggles; the solvent defats skin.
• Narcotic effects (H336) — vapors may cause drowsiness or dizziness; provide adequate ventilation or local exhaust.
• Organ effects on repeated exposure (H373) — limit prolonged/repeated contact; follow exposure controls for the carrier solvents.
• Bond and ground all transfer equipment; use non-sparking tools and explosion-proof electrical fittings. Exact hazards are SDS-dependent — consult the supplier SDS.

Common questions

Is a polyglycol demulsifier safe in an HDPE or XLPE poly tank?

No. The polyglycol active alone would be compatible, but finished demulsifiers are carried in aromatic solvents (xylene / heavy aromatic naphtha) that polyethylene resistance charts rate Unsatisfactory — they swell and permeate the tank wall. Use steel, lined steel, or stainless instead.

What tank should I use for demulsifier storage?

Carbon steel (UL-142 or lined), 304/316 stainless, or a solvent-resistant vinyl-ester FRP specified for aromatic service. Because it is a flammable liquid, UL-142 steel tankage with bonding, grounding, and ventilation is the common standard of practice.

Does the product have a meaningful pH?

Not really. It is a non-aqueous solvent blend, so pH is generally not applicable. Compatibility is driven by the aromatic/alcohol solvent system, not by acidity or alkalinity.

Why is the polyglycol active fine but the product is not?

The polyglycol/glycol-ester surfactant is polyethylene-compatible on its own. The finished demulsifier is dominated by its flammable aromatic-solvent carrier, and that carrier dictates both the fire rating and the materials of construction.