What is pet coke as a sea-borne cargo?
Petroleum coke (pet coke) is a refinery residue from delayed coker units, shipped as a high-carbon fuel and anode feedstock. The IMSBC PETROLEUM COKE schedule covers both uncalcined (green) and calcined grades, with Group B classification driven by sulphur and dust.
Pet coke sits in a tighter sea-borne trade than coal, with most recent estimates placing global sea-borne volume in the 50 to 70 million tonne range annually. It is produced as a residual solid at oil refineries running delayed coker units on heavy crude slates, and it ships in two distinct physical and commercial grades. Uncalcined or “green” pet coke is the raw coker output and ships predominantly as a fuel into cement kilns and into power-generation kilns in markets where coal is regulated more tightly than petcoke. Calcined pet coke has been further processed in a rotary kiln to drive off volatiles and is shipped as anode-grade feedstock into the aluminium-smelting industry.
The regulatory anchor for sea carriage is the IMSBC Code 2024, schedule entry PETROLEUM COKE (uncalcined or calcined). The schedule classifies the cargo Group B, meaning a chemical and dust hazard rather than a liquefaction risk. The dominant operational concerns are sulphur emission (petcoke is sulphur-rich relative to most thermal coals), respirable dust at load and discharge, and a residual self-heating sensitivity on freshly produced uncalcined material. P and I club guidance addresses the uncalcined versus calcined classification distinction and US PHMSA petcoke-handling guidance is a useful operational reference at US Gulf load ports.
Pet coke cargo properties
| Property | Value | Unit / Reference |
|---|---|---|
| Stowage factor | 1.25 to 1.67 | m3/t, varies by grade and particle size (IMSBC Code 2024, PETROLEUM COKE schedule) |
| IMSBC group | Group B | Chemical and dust hazard, not liquefaction |
| IMSBC schedule entry | PETROLEUM COKE (uncalcined or calcined) | Single schedule covers both grades, with sub-grade declaration in the cargo declaration |
| Bulk density | 0.6 to 0.8 | t/m3, calcined slightly denser than uncalcined (599 to 800 kg/m3, IMSBC schedule) |
| Angle of repose | Not applicable | Not specified in the PETROLEUM COKE schedule |
| Transportable moisture limit | Not applicable | Group B, TML applies only to Group A cargoes |
| Hazard profile | Sulphur, dust, residual self-heating on fresh uncalcined | IMSBC Code PETROLEUM COKE schedule |
| Reference | IMSBC Code 2024 edition | International Maritime Solid Bulk Cargoes Code, IMO |
The PETROLEUM COKE schedule treats uncalcined and calcined grades as variants of the same cargo and requires the shipper to declare which grade is presented. The operational implications diverge: uncalcined material is occasionally hot off the coker drum at the load port and can retain residual heat that needs to dissipate before loading commences, while calcined material is essentially inert chemically but is dustier in handling. Sulphur is the structural concern across both grades: pet coke can carry 3 to 7 pct sulphur on a weight basis, which exceeds typical thermal coal by a factor of two to five, and the long-run consequence is paint and steel corrosion in the holds and on deck. Dust emission is a port-acceptance issue, not a vessel-integrity issue, but it drives loading restrictions and occasionally fines at receiving terminals near residential areas.
Vessel typing and parcel sizes
| Vessel class | Suitability | Typical parcel size | Notes |
|---|---|---|---|
| Capesize | Common | 150,000 to 180,000 t | US Gulf and Saudi long-haul to India and China. Draught fit at US Gulf coker terminals is the binding constraint. |
| Panamax | Dominant | 65,000 to 82,000 t | Workhorse for US Gulf to India, US to Mediterranean, Venezuela to Asia. Hold cleanliness critical between fuel grades. |
| Supramax | Common | 50,000 to 63,000 t | Geared for receivers without shore cranes, especially Indian west coast cement-kiln terminals. |
| Handysize | Conditional | 25,000 to 38,000 t | Niche regional trade, smaller cement and power-station feed parcels. |
Pet coke parcel-size economics are similar to coal because the stowage factors are comparable, but with a smaller absolute trade volume the dominant typing settles a notch lower. Panamax is the workhorse for the US Gulf to India lane, which is the single largest pet coke trade, while Capesize lifts occur on the longer Atlantic-to-Asia and Saudi-to-Asia routes where the freight saving per tonne justifies the larger vessel. Hold cleanliness is the same recurring discipline as in coal: a vessel that lifted pet coke and is then nominated for a cleaner cargo needs a full wash and grade-up to clear inspection.
How pet coke ships in practice
Pet coke loads predominantly by shore conveyor at refinery-adjacent terminals (US Gulf coker complexes, Saudi refinery exports, Venezuelan refinery exports) or by grab from open storage at less-integrated terminals. Loading rates run from 15,000 to 35,000 t per day depending on the conveyor profile and the receiving vessel’s hatch configuration. The IMSBC schedule does not impose a surface-levelling requirement comparable to coal, but most port surveyors will require basic trimming before sailing for stability and stowage purposes.
Voyage care for pet coke is lighter than coal but not trivial. Fresh uncalcined material can retain residual heat from the coker drum at loading, and the operational standard is to allow the cargo to cool to ambient before close-out of hatch covers. Once at sea, hatch covers are kept closed and weather-tight. Sulphur and salt-air interaction can accelerate paint breakdown on uncoated steel surfaces, and coal-and-petcoke fleets typically run a more aggressive paint maintenance cycle than mineral-cargo fleets. Discharge is by grab and shore crane at most receivers, with bag-house or water-spray dust suppression at terminals near residential areas. The fixture is typically on FIO terms under voyage charter, with the dust-suppression and port-restriction clauses carrying material risk if mis-allocated.
Major trade routes
- US Gulf to India: ~15 to 20 M t/yr from Houston, Beaumont and Corpus Christi coker complexes to Indian west coast cement and power receivers, Panamax-dominant, the single largest pet coke lane.
- US Gulf and US East Coast to Mediterranean: ~5 to 8 M t/yr to Spanish, Italian and Turkish cement kilns, Panamax and Supramax, structurally stable but subject to European environmental restrictions.
- Venezuela to Asia and Caribbean: ~3 to 5 M t/yr, Panamax, structurally constrained by Venezuelan refinery output and sanctions exposure.
- Saudi Arabia to India: ~3 to 5 M t/yr from Jubail and Yanbu refinery exports, Panamax and Capesize, growing on Saudi downstream expansion.
- US Gulf to China: ~2 to 4 M t/yr, Capesize and Panamax, sensitive to Chinese aluminium-anode demand and environmental policy windows.
- Russia and Mediterranean to West Africa: smaller regional flows, Supramax and Handysize.
The US Gulf is the structural dominant origin, accounting for roughly half of global sea-borne pet coke trade on most recent estimates, with Indian and Mediterranean cement-kiln demand as the main destination cluster. Lane structure is more receiver-driven than coal because end-use is concentrated in a smaller number of buyer industries. The routes-markets hub carries the wider lane catalogue.
Pet coke vs coal
Pet coke and coal are the two dominant Group B fuel cargoes in dry bulk and are routinely confused at cargo-order stage, particularly by trading desks that handle both. The two are not interchangeable for loadport, voyage care or receiver-acceptance purposes.
| Pet coke (uncalcined) | Coal | |
|---|---|---|
| IMSBC group | Group B | Group B |
| Stowage factor | 1.25 to 1.67 m3/t | 0.79 to 1.53 m3/t |
| Sulphur content | 3 to 7 pct typical | 0.5 to 2 pct typical |
| Self-heating | Residual on fresh uncalcined, modest overall | Active and continuous, primary voyage concern |
| Methane emission | Negligible | Active, COAL schedule special precautions monitoring |
| Dust handling | Significant, port-acceptance issue | Significant, port-acceptance issue |
| IMSBC schedule | PETROLEUM COKE (uncalcined or calcined) | COAL |
Use the PETROLEUM COKE schedule when the commodity is a delayed-coker output (green pet coke) or rotary-kiln-calcined pet coke for anodes. Use the COAL schedule when the commodity is mined coal. Pet coke is bulkier per tonne (lower bulk density, higher stowage factor), sulphur-richer, and lower-self-heating than mined coal, and the IMSBC monitoring discipline differs: pet coke does not require continuous methane and oxygen monitoring under the schedule, while coal does. A fixture written against the wrong schedule will fail the loadport surveyor’s documentation review.
Reference example
Panamax uncalcined pet coke, US Gulf to West coast India
- Cargo grade
- 70,000 mt uncalcined petroleum coke, 4.5 pct sulphur, 10 pct molo
- Lane
- US Gulf coker terminal to West coast India cement receiver range
- Vessel band
- Modern Panamax, 78,000 dwt
- Parcel size
- 70,000 mt
- Loading rate
- 20,000 T/D SHINC, shore conveyor
- Discharge rate
- 15,000 T/D SHINC, grab and shore crane with dust-suppression
- Notable clause
- Cargo declaration confirming uncalcined sub-grade under PETROLEUM COKE schedule, dust-suppression cost allocated to receiver, freight prepaid against original BL
The lane runs roughly 9,500 nautical miles one way around Cape of Good Hope. At a stowage factor of around 1.30 m3/t the vessel loads close to full holds, which is the normal load picture for a Panamax pet coke voyage on the US Gulf to India lane.
Pre-loading documentation included a cargo declaration filed under IMSBC Section 4 and a sulphur content certificate at 4.5 pct. The shipper declared uncalcined sub-grade, and the master confirmed that the cargo was not hot off the drum at load by reference to the terminal’s stockpile-age log. Holds were prepared by sweep and freshwater rinse from the previous voyage and surveyed grain-clean before loading commenced.
The fixture was on FIO terms with laytime calculated against weather working days SHINC at both ends. Demurrage was set at the spot Panamax daily TCE for the month of fixture. Dust-suppression cost at the receiving terminal was allocated to the receiver under a bespoke clause, which is the standard ask on Indian west-coast pet coke discharges given the residential adjacency of some kiln terminals.
Common loading and discharge issues
- Dust emission and port restrictions: Indian and Mediterranean discharge ports near residential areas increasingly impose dust-suppression requirements (water spray, bag-house, covered conveyor) and occasional outright bans on uncovered grab handling. The cargo handling clause must align with the receiving port’s published norm or the cost falls on the wrong party.
- Hot loading on fresh uncalcined material: freshly produced green pet coke can retain coker-drum heat and is not safe to load until cooled. The master is entitled to refuse loading on this basis, and IMSBC Code guidance supports the position.
- Uncalcined versus calcined misdeclaration: shippers occasionally declare the wrong sub-grade on the cargo declaration, which causes surveyor delay at the loadport and exposes the charterer to the resulting laytime cost. P and I club guidance is mature on the classification distinction.
- Sulphur corrosion damage: cumulative across a pet-coke programme this is a hidden cost that affects paint, steel and electrical equipment near the hatch coamings. It does not show up on a single fixture but compounds across the drydock cycle.
- Hold cleanliness for the next cargo: residual pet coke dust will fail a grain-clean or alumina inspection, and the wash-up routine is longer than for coal because of the sulphur residue.
- Receiver acceptance limits on sulphur and metal content: some Indian cement kilns and European receivers have contractual sulphur and vanadium ceilings, and shipments outside spec are subject to deduction or rejection. The cargo certificate must be aligned with the receiver’s acceptance criteria before fixture.
Scope and what this page does not cover
This page explains petroleum coke as a sea-borne dry bulk commodity, the IMSBC operational regime that governs uncalcined and calcined carriage, and the dominant vessel-class and lane structure. It does not forecast pet coke prices, opine on which refinery origin to fix from next quarter, or interpret jurisdiction-specific case law on cargo claims arising from sulphur or dust incidents. For those, work with chartering counsel and a desk broker against current Argus and Roskill data.