Methanol
The specification is settled. The tank is the variable.
Methanol to the IMPCA Reference Specification, as seaborne parcels and ISO tanks. One of the few products we handle where the specification is genuinely global and stable — which moves the entire risk onto contamination, and onto what the tank did last.
The desk
When the specification stops being the argument, the logistics become it.
Almost every product on our book has a specification argument at its centre — which edition, which table, which national variant. Methanol does not. The IMPCA Reference Specification is used worldwide, it is stable, and both sides of a trade generally mean the same thing by it.
That is genuinely unusual, and it changes where the risk lives. If the product specification is not in dispute, then what remains is contamination: water, which methanol is fully miscible with and therefore cannot be settled out; iron, which comes from the steel the cargo travelled in; and whatever the previous cargo left behind.
So on methanol we spend our attention on tank history, on the loading and discharge lines, and on the two or three parameters that are really contamination detectors dressed up as quality tests. The specification is the easy part.
The standard
IMPCA Reference Specification, version 10.
The current version is Version 10, dated 25 October 2024. As always, the version belongs in the contract — the test methods in particular have been revised across versions, and citing "IMPCA" without one leaves the method open even when the limit is not.
| Parameter | Limit | Method |
|---|---|---|
| Appearance | Clear and free from suspended matter | IMPCA 003 |
| Purity, dry basis | 99.85 % w/w min | IMPCA 001 |
| Water | 0.100 % w/w max | ASTM E 1064 |
| Acetone | 30 mg/kg max | IMPCA 001 |
| Ethanol | 50 mg/kg max | IMPCA 001 |
| Chloride, as Cl | 0.5 mg/kg max | IMPCA 002 |
| Sulphur | 0.5 mg/kg max | ASTM D 3961 / D 5453 |
| Iron, in solution | 0.10 mg/kg max | ASTM E 394 |
| Colour | 5 Pt-Co max | ASTM D 1209 / D 5386 |
| Specific gravity, 20/20 °C | 0.7910–0.7930 | ASTM D 4052 |
| Distillation range at 760 mmHg | 1.0 °C max | ASTM D 1078 |
| Potassium permanganate time at 15 °C | 60 minutes min | ASTM D 1363 |
| Water miscibility | Pass | ASTM D 1722 |
| Carbonizables | 30 Pt-Co max | ASTM E 346 |
| Acidity, as acetic acid | 30 mg/kg max | ASTM D 1613 |
| Non-volatile matter | 8 mg/1,000 ml max | ASTM D 1353 |
Reading the table
Half of those lines are contamination detectors.
A methanol certificate looks like a purity report. It is better understood as a set of tests for particular things going wrong, each of which points at a specific cause.
| Parameter | What it is really testing for |
|---|---|
| Iron in solution, 0.10 mg/kg | Rust. Methanol picks up iron from unlined carbon steel tanks, lines and hoses, and dissolved iron then poisons catalysts downstream. This is the single most common reason a cargo that left on-specification arrives off it, and it is a tank and line question, not a producer question. |
| Potassium permanganate time, 60 minutes | Oxidisable impurities in aggregate — a broad-spectrum test that catches contamination the specific tests were not designed to find. A short permanganate time on an otherwise clean certificate is a signal to stop and look at the history. |
| Carbonizables | Material that chars under acid. Another aggregate contamination indicator rather than a named impurity. |
| Distillation range, 1.0 °C | A purity proxy. Pure methanol boils over a very narrow range; anything that widens it is something else in the cargo. |
| Chloride, 0.5 mg/kg | Stress corrosion cracking in stainless steel downstream, and catalyst damage. A very tight limit for a reason. |
| Acidity | Corrosion, and a marker of oxidation in storage. |
| Non-volatile matter | What is left after evaporation. Solids, and evidence of carry-over from a dirty system. |
| Appearance and colour | The cheapest tests on the sheet, and the first indication of a problem. Methanol should be water-clear. |
Water
Fully miscible, which means it cannot be settled out.
On a hydrocarbon cargo, free water sinks to the tank bottom and can be drained. Methanol and water mix completely in all proportions, so water contamination is homogeneous, invisible, and not removable by any operation available on a ship or at a terminal.
The consequences are worth stating plainly. A wet tank, a wet line, residual tank-cleaning water or an ingress during a rainy discharge does not produce a layer to be drained — it produces a cargo with a higher water content throughout. If that pushes the parcel above 0.100 % w/w, the cargo is off-specification and there is no shipboard remedy.
Which is why dryness of the receiving system is a contractual matter on this product, not a housekeeping one, and why the water result at discharge is the number both sides watch. It is also why we ask about tank-cleaning method and drying, not merely about the previous cargo.
Destinations
Who buys it, and what each one cares about.
Formaldehyde and resins
The largest single chemical outlet. Silver or metal-oxide catalysts, so iron, chloride and sulphur are the parameters that matter most.
Acetic acid
Carbonylation, with catalyst systems sensitive to trace contaminants. Purity and the aggregate contamination tests carry real weight here.
MTBE and TAME
Gasoline ethers — the link back to our gasoline desk, where the ether ceiling and the oxygen limit decide how much can go in.
Olefins — methanol to olefins
Large-volume methanol into ethylene and propylene. Feed consistency matters as much as any single parameter.
Biodiesel
Transesterification of vegetable oils and fats. Water content is the critical parameter — water drives the reaction toward soap formation rather than ester.
Marine fuel
An emerging outlet as shipping looks past conventional bunkers. We supply methanol as a cargo; delivery into a ship is a bunkering operation and not something we do — see Marine Fuels.
Carriage & safety
A chemical tanker cargo, and a genuinely dangerous liquid.
Methanol moves as a bulk liquid chemical, not as an oil product, and it deserves more caution than its familiarity suggests.
| Item | Position |
|---|---|
| Tank type | Stainless steel or an appropriate coating. Unlined carbon steel is the source of the iron problem described above, and we ask what the tank is made of rather than assuming. |
| Tank history and cleaning | Three-cargo history as standard, plus the cleaning and drying method. On a water-miscible cargo, how the tank was dried matters as much as what it held. |
| Inerting | Nitrogen blanketing where required. Methanol's flammable range is wide and its flash point low. |
| Toxicity | Toxic by ingestion, inhalation and skin absorption, with a delayed onset that makes exposure easy to underestimate. Handling is closed, and the safety data sheet travels in the destination language as a matter of course. |
| Fire behaviour | Burns with a pale, almost invisible flame in daylight. Relevant to terminal and vessel emergency planning, and a reason methanol is treated differently from a hydrocarbon of similar flash point. |
| Parcels | Chemical and parcel tankers, and ISO tank containers for smaller lots. FOB, CFR, CIF or delivered to a nominated terminal. |
Scope
Where our obligation ends.
- What we supply
- Methanol to the IMPCA Reference Specification as seaborne parcels and ISO tanks, with independent inspection at both ends.
- What we do not do
- We do not produce methanol, we do not operate storage terminals or drumming facilities, and we do not bunker ships.
- Renewable and low-carbon methanol
- Where a cargo carries a sustainability claim, that claim has to be certified and documented to audit standard — we handle it as a certified stream with evidence attached, on the same basis as our certified components, rather than as a description on an invoice.
- Tank dryness
- The receiving system's condition is the buyer's. We will raise it, we will ask what the tank held and how it was dried, and we will decline a fixture where the answer suggests the cargo cannot arrive on-specification.
How to specify
Six lines and we can price it.
Shorter than most, because the specification is not the variable here.
IMPCA version
The version and date, so the test methods are fixed as well as the limits. Plus any parameter you need tighter than the reference.
Optional parameters you need
Trimethylamine and aromatics are optional in the reference specification. If your process is sensitive, make them contractual.
Your process
Formaldehyde, acetic acid, ethers, olefins, biodiesel or fuel use. It tells us which contamination parameters to watch hardest.
Receiving tank
Material, coating, previous cargo and drying method. On this product that is a quality question.
Quantity, format and basis
Tonnes, bulk parcel or ISO tanks, FOB / CFR / CIF / delivered, one lot or a term programme.
Pricing basis
Posted contract price reference or spot, with the publication and pricing period named.
Quality
Tested at both ends, because the voyage is the risk.
Independent inspection by an agency appointed for the cargo — SGS, Bureau Veritas or Intertek — instructed jointly, sampling under supervision at a point agreed in advance, with sealed retains at both ends.
Methanol is the product where load-port and discharge-port analysis most often differ, and the differences are informative rather than random: iron points at the tank, water at the system's dryness, and permanganate time at something nobody has named yet. Testing only at load is testing the wrong end.
- Full IMPCA set
- Every parameter in the table above, with the method designation stated rather than left as "ASTM".
- Watched hardest
- Water, iron in solution, permanganate time, chloride and appearance. Those five carry most of the information about what happened between load and discharge.
- Tank documentation
- Three-cargo history, tank material and coating, cleaning and drying method, and a dry-tank certificate where the receiving system requires one.
- Retained samples
- Sealed retains at both ends, so a water or iron dispute is settled on the cargo rather than on correspondence.
- Documentation per parcel
- Certificate of Quality, Certificate of Analysis, Certificate of Quantity, Certificate of Origin, safety data sheet in the destination language, bill of lading, tank history and the independent inspection report.
Straight answer
What we will tell you before you ask.
- That the specification is the easy part
- IMPCA is stable and both sides mean the same thing by it. If a methanol trade goes wrong it is contamination, and contamination is a logistics question.
- That water cannot be drained out of methanol
- Full miscibility means no layer, no settling, no shipboard fix. A wet system produces an off-specification cargo, so we ask about drying and not just about the previous cargo.
- That iron in solution is a tank problem
- Not a producer problem. If dissolved iron is high at discharge, the answer is in the steel the cargo travelled in, and the fix is the next fixture rather than this one.
- That permanganate time is the test worth reading first
- It catches contamination the named tests were not designed to find. A short time on an otherwise clean sheet is a reason to look harder, not to accept the pass.
- That a sustainability claim needs certification, not adjectives
- Renewable or low-carbon methanol is a documented, audited stream or it is a description. We will supply the first and decline to write the second.
- 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.