LPG
The molecule is rarely the problem. The terminal is.
Commercial propane and butane, C3/C4 mixes, EN 589 autogas and petrochemical feed — matched to the reception regime you actually have, because a fully refrigerated cargo and a pressurised terminal cannot be reconciled by negotiation.
The desk
Two questions settle most LPG enquiries, and neither is about price.
LPG is a simple product with an unusually unforgiving logistics chain. Propane and butane are well-defined molecules, the specifications are stable, and the analysis is routine. What goes wrong is almost never the composition.
The first question is how your terminal receives. LPG moves under pressure at ambient temperature, or refrigerated at atmospheric pressure, or somewhere between — and a ship, a shore tank and a discharge arm have to agree on which. A fully refrigerated cargo arriving at a pressurised installation is not a commercial problem to be split; it is a cargo that cannot be discharged.
The second is whether the product is odourised. Domestic and autogas markets generally require it. Petrochemical users cannot use it. Odourisation is irreversible, so it has to be decided before loading rather than after — and an odourised parcel offered as cracker feed tells you the seller has not thought about where it is going.
Carriage & reception
Pressurised, semi-refrigerated, fully refrigerated.
The same propane travels three ways, and each one implies a different vessel, a different shore installation and a different parcel size. Establishing which applies is the first thing we do on an enquiry.
| Regime | How the cargo is held | Typical use |
|---|---|---|
| Pressurised | Ambient temperature, contained by pressure in cylindrical or spherical vessels. Small parcels. | Coastal and regional distribution, bottling plants, island and short-sea supply. The most common reception regime for smaller markets. |
| Semi-refrigerated / semi-pressurised | Partly chilled and partly pressurised, so the tanks are lighter than fully pressurised for the same volume. | Mid-size parcels and the most flexible of the three — a semi-ref vessel can usually serve both pressurised and refrigerated shore installations, which is why it commands what it commands. |
| Fully refrigerated | At atmospheric pressure and low temperature — around −42 °C for propane, near 0 °C for butane. Large parcels on the biggest gas carriers. | Long-haul cargoes into import terminals with refrigerated storage. The cheapest freight per tonne and the least flexible destination set. |
Odourisation
Irreversible, and it decides the buyer pool.
LPG is odourless. Because it is heavier than air and collects at low level, most jurisdictions require an odourant — typically ethyl mercaptan or tetrahydrothiophene — in product destined for domestic, commercial and automotive use, so a leak is detectable well below the flammable limit.
EN 589 puts it as a performance requirement rather than a dosage: the odour must be distinctive and unpleasant at 20 % of the lower flammability limit. That is the right way to write it, because odourant loss and adsorption vary with the system.
The commercial consequence is the part that gets missed. Odourant is a sulphur compound, and it cannot be removed afterwards. An odourised cargo is therefore unusable as petrochemical feedstock — a cracker or a dehydrogenation unit will not take the sulphur, and no amount of blending fixes it. So odourisation is not a finishing step. It is a decision about who the cargo can be sold to, taken at the loading terminal.
Grades
What we supply, and what each buyer holds.
Commercial propane
Bottling, domestic and commercial heating, crop drying, and industrial burners. Bought on vapour pressure, residue and sulphur, and odourised to the destination's requirement.
Commercial butane
Bottling in warm climates, aerosol propellant and lighter refill service, and gasoline blending. Vapour pressure is lower, so cold-weather vaporisation is the constraint that limits where it can be used neat.
C3 / C4 mixes
Blended to a destination's seasonal requirement. The mix ratio is the specification — and it should be written as a ratio with a tolerance, not as "mix".
Autogas
To EN 589, with the winter volatility grade matched to the market. Octane is specified as MON, and odourisation is required.
Petrochemical feed
Cracker feed and propane dehydrogenation feed. Unodourised, with tight limits on sulphur, dienes, ethane and propylene depending on the unit. This is a different product commercially from the same molecule sold for heating.
Parcels and formats
Pressurised, semi-refrigerated and fully refrigerated cargo parcels; ISO tank containers; road tankers where the trade supports it. FOB, CFR, CIF or delivered.
The standard
EN 589, where autogas is concerned.
The European automotive LPG specification. As with every standard we quote against, the edition belongs in the contract — the sulphur limit in particular has tightened across revisions, so "to EN 589" without a year leaves the number open.
| Parameter | Limit | What it governs |
|---|---|---|
| Motor octane number | 89.0 min | Knock resistance. LPG's octane is high by nature, so this is a floor rather than a differentiator. |
| Total dienes | 0.5 % m/m max | Gum and deposit formation in the fuel system. Also a marker of cracked-stream content. |
| Hydrogen sulphide | Negative | A pass/fail. Corrosion and a personnel hazard. |
| Total sulphur, after odourisation | 30 mg/kg max in the current edition | Aftertreatment protection. Measured after the odourant is added, which is the point — the odourant itself consumes part of the allowance. |
| Copper strip corrosion | Class 1 | Corrosivity as presented. |
| Evaporation residue | 60 mg/kg max | Heavy ends that do not vaporise. They accumulate in vaporisers and injectors, and this is the parameter that quietly ruins a vehicle fleet. |
| Vapour pressure at 40 °C | 1,550 kPa max | System pressure rating. The upper bound on how propane-rich the blend can be. |
| Winter grade — temperature at which gauge vapour pressure is at least 150 kPa | −5 °C max, by market | The seasonal parameter. It guarantees the fuel still vaporises in cold weather, and it is set nationally — the LPG equivalent of a diesel cold-flow grade. |
| Water content | Pass — free water absent | Icing at the pressure regulator, and corrosion. |
| Odour | Distinctive and unpleasant at 20 % of the lower flammability limit | Leak detection. Written as performance rather than dosage. |
Pricing
Three references, and the one you use follows the trade route.
LPG does not price off a single global benchmark. Which reference applies is a function of where the cargo comes from and where it goes, and mixing them up is a real source of mispricing.
- Saudi Aramco Contract Price
- The monthly producer price that anchors much of the Middle East export trade and the markets it serves. Published monthly, which makes the pricing month a contract term worth pinning rather than assuming.
- Mont Belvieu
- The US reference, relevant wherever the cargo has a US Gulf origin — which is a large and growing share of the seaborne market.
- North West Europe
- The regional reference for European cargoes, quoted separately for propane and butane, whose spread moves seasonally.
- What to fix in the contract
- The reference, the publication, the pricing period, and whether propane and butane in a mixed cargo price separately. A differential agreed without those is not yet a price.
Scope
Where our obligation ends.
- What we supply
- LPG as cargo parcels and ISO tank lots into terminals and shore storage, with independent inspection and full documentation.
- What we do not do
- We do not bottle, we do not operate filling plants or autogas stations, and we do not distribute to end users. We do not own vessels or terminals.
- Odourisation
- Performed at the loading terminal to the destination's requirement and certified. We will not represent an odourised cargo as suitable for petrochemical service, and we will tell you plainly when a parcel's odourisation status closes a market to it.
- Reception compatibility
- We will establish it before quoting, and we will decline rather than fix a cargo against a terminal that cannot take it. Vessel and terminal compatibility is a safety matter before it is a commercial one.
How to specify
Six lines and we can price it.
The first two are the ones that decide whether a cargo can serve you at all.
Reception regime and storage
Pressurised, semi-refrigerated or fully refrigerated; storage type, temperature and capacity; discharge arm and berth limits.
Odourised or not
And if odourised, to which national requirement. If the product is going to a cracker or a dehydrogenation unit, say so — it must not be odourised.
Product and composition
Propane, butane or a mix stated as a ratio with a tolerance. For petrochemical feed, your ceilings on ethane, propylene, dienes and sulphur.
Standard and season
EN 589 with an edition for autogas, or the destination's national specification. The winter volatility grade if the market sets one.
Quantity, parcel size and basis
Tonnes, FOB / CFR / CIF / delivered, one cargo or a term programme with monthly liftings.
Pricing reference
Which of the three, which publication, and the pricing period.
Quality
Composition by chromatograph, and the residue nobody asks for.
Independent inspection by an agency appointed for the cargo — SGS, Bureau Veritas or Intertek — instructed jointly, with sampling under supervision. On a pressurised liquefied gas, sampling is a procedure with its own hazards and its own failure modes, and it is done by the inspector rather than by the terminal alone.
- Core test set
- Full composition by gas chromatography — C2, C3, C4 and heavier, with olefins reported separately; vapour pressure; density; total sulphur; hydrogen sulphide; copper strip corrosion; evaporation residue; free water; and total dienes where a cracked stream is involved.
- The parameter to insist on
- Evaporation residue. It is the one buyers most often leave off, and heavy ends that do not vaporise are the classic cause of damage in vaporisers, regulators and injectors — damage that appears weeks after the cargo has been paid for.
- Odourisation
- Certified where required, with the odourant named and the sulphur reported after dosing rather than before.
- Quantity
- By ship's figures and shore figures, with the governing figure named in the contract. On refrigerated cargoes, temperature and density at measurement are recorded with the volume.
- Documentation per parcel
- Certificate of Quality, Certificate of Quantity, Certificate of Origin, odourisation certificate where applicable, safety data sheet in the destination language, bill of lading and the independent inspection report.
Straight answer
What we will tell you before you ask.
- That the reception regime decides the trade
- Before price, before origin. If your terminal is pressurised, a fully refrigerated cargo is not an option at any level, and we would rather establish that in the first reply.
- That odourisation cannot be undone
- It closes the petrochemical market to a cargo permanently. Anyone offering odourised product as cracker feed either does not know or is hoping you do not.
- That "C3/C4 mix" is not a specification
- Write the ratio and the tolerance. Seasonal markets move the ratio, and an unstated mix is an argument waiting for a cold week.
- That evaporation residue is the sleeper parameter
- Rarely specified, and the usual cause of vaporiser and injector damage. We report it whether or not you ask.
- Where an origin cannot be cleared
- Screened per consignment; declined where it cannot be documented, and not referred onward — see Compliance.
Enquiries
Every enquiry is answered by the desk that handles it.
Send the product, quantity, delivery basis, destination and timing. We revert with availability, an indication and the documentation that accompanies it. Specifications are released once we know who we are speaking with.