Efficient and compliant tank cleaning with proven impact on fuel and maintenance performance

Tank Cleaning — Technical Specification

Integrated Cleaning Framework

Seachios® delivers tank cleaning for HFO/IFO, VLSFO/LSFO, MGO/DO, slop, settling/service tanks and selected cargo tanks using a combined methodology: fixed tank cleaning machines (rotary jet/Butterworth), controlled hot-wash cycles, high-pressure hydrojets, and cargo-specific chemical systems. Operations are governed by MARPOL Annex I, SOLAS, ISGOTT, Port State Control and internal HSE standards (confined-space entry, LOTO, ATEX equipment, gas testing). Waste streams are segregated and transferred to Port Reception Facilities (PRF) with full chain-of-custody and Oil Record Book documentation.

Tank Types and Typical Contamination

* Cargo/chemical tanks are treated only where scope and coating compatibility permit.

Process Workflow

Step 1 — Isolation, Permits & Gas Testing

• Permit-to-Work (PTW), LOTO of lines/pumps/heaters, inerting status verified.

• Confined-space entry per ISGOTT/NR-33: O₂ ~20.9%, HC vapors < 10% LEL (or stricter terminal limit), toxics < TLV.

• Bonding/earthing in place; EX/ATEX portable equipment only.

Step 2 — Sludge Management & Pre-Drain

• Drain to slop; mucking/suction of settled sludge and cat-fine sediment.

• Circulate/hear oil (if safe) to reduce viscosity before removal.

Step 3 — Mechanical Cleaning (Fixed Machines)

• Rotary jet/Butterworth heads on programmable patterns (short/long cycles).

• Typical operating window: 10–18 bar (145–260 psi) and 20–60 L/min per head.

• Hot-wash 50–80 °C (122–176 °F) where coating and safety allow.

• Multiple passes for baffles, shadow zones, stiffeners.

Step 4 — High-Pressure Hydrojet Assistance

• Portable hydrojets 200–500 bar (2,900–7,250 psi) for heavy deposits, frames, ladders, sumps, suctions.

• Rotating/fan nozzles selected to match coating limits and residue hardness.

Step 5 — Chemical Treatment (Cargo-Specific)

• Alkaline degreasers for heavy petroleum residues/asphaltenes.

• Solvent boosters/emulsifiers (coating-compatible) for wax/varnish films.

• Neutral detergents for veg-oil/cargo odor, food-grade contexts.

• Microbicides/biocides (as allowed) for diesel-bug remediation in MGO.

• Demulsifiers for slop phase separation; neutralizers if acidic carryover.

• Dosing via fixed heads or recirculation; controlled soak times before rinse.

Step 6 — Rinsing, Stripping & Line/Heater Clean-through

• Fresh-water rinse to remove chemical traces; hot potable water if required.

• Strip lines, purge heaters/coils and suction bellmouths; verify drains.

Step 7 — Gas Freeing & Ventilation

• Continuous ventilation/blowers (explosion-proof), air-changes documented.

• LEL trending and dew-point control to avoid condensate/flash rust.

Step 8 — Inspection, Sampling & Handover

• Visual & wipe tests, drip-sample/line flush for fuel paths.

• ISO 8217 readiness for fuel quality; odor checks for cargo/veg-oil tanks.

• Handover pack: photos/videos, measurements, PRF receipts, ORB entries.

Technical Parameters & Controls

• Fixed-machine cycles: selectable angles (e.g., 60°/90°/120°), programmable dwell for heavy zones.

• Temperature control: hot-wash limited by coating spec and flashpoint; interlocks prevent overheating.

• Nozzle selection: rotating vs. fan jets; orifice matched to flow/pressure envelope.

• Compatibility: coating datasheets govern chemical pH/solvent use and max temperature.

• Safety interlocks: LEL/O₂ interlocks on blowers; manwatch and rescue plan per confined-space rules.

• Documentation: PTW, gas tests, SDS for chemicals, risk assessments, toolbox talks logged.

Residues and Treatment Matrix

Fuel/Cargo Readiness Standards

• Fuel-system readiness: lines/heaters free of sludge, water bottoms removed, samplable points clean for ISO 8217 verification.

• Changeover compliance: tanks/lines prepared to prevent cross-contamination when switching HFO↔VLSFO↔MGO.

• Terminal/PSC auditability: gas-free certificates, PRF receipts, ORB entries, SDS and PTW bundle available for inspection.

• Odor-critical cargo readiness (where applicable): neutral pH, no film/odor residue, wipe tests acceptable to surveyor.

KPIs and Performance Envelope

• Cycle time: machine passes sized to tank geometry; heavy fouling may require multi-pass + hydrojet assist.

• Ventilation time: driven by LEL decay and dew-point targets; logged trend required before entry/handover.

• Quality gates: interim inspections after each major step (mechanical → chemical → rinse → gas-free).

• Non-conformities: punch-list, root-cause, and re-clean plan issued before final sign-off.

Waste & Environmental Management

• Segregation: oils, emulsions, and solids kept in separate streams; chemicals documented by SDS.

• MARPOL Annex I compliance: no overboard discharge; all oily residues to PRF with receipts.

• Oil Record Book: entries for transfer/handling; reconciliation with PRF documentation.

• Spill prevention: drip-trays, absorbents, sealed transfer; emergency kit staged and briefed.

Safety & Risk Management

• Confined Space: NR-33/ISGOTT compliance, standby rescue, continuous gas monitoring.

• ATEX/EX: certified blowers, lighting, instruments; bonding/earthing throughout.

• PPE: chemical-resistant clothing, eye/face protection, intrinsically safe comms, fall protection.

• Hot vs. Cold Work: hot work only after documented gas-free/permit; cold work within LEL and toxic limits.

• Toolbox Talks: pre-job hazards, chemical handling, emergency communications and evacuation.

Deliverables & Documentation

• Operational report with timestamps, photos/videos, machine settings, chemical lots, temperatures, pressures, flow rates.

• Gas-free and cleanliness certificates as applicable; PRF receipts, ORB extracts, PTW bundle.

• Recommendations for coating care, changeover strategy, and preventive maintenance intervals.