The Claw — Vessel Integration & General Arrangement
The Claw -- Vessel Integration & General Arrangement
How every subsystem physically connects on an Aframax tanker conversion to form a functioning plasma processing vessel. This is the systems-level view that ties together the subsystem research into a unified ship design.
This document does NOT repeat subsystem details. It references:
- Internal Layout (node 54) for deck zones and space allocation
- Retrofit Engineering (node 55) for strip-out scope and structural mods
- Operations Plan (node 56) for power budgets and daily procedures
- PRRS Deep Dive (node 46) for reactor specifications
- Feedstock Science (node 65) for material flow and storage sizing
- Collection Systems (node 6) for collection hardware specs
- Syngas (node 22) for gas cleanup train specs
1. Process Flow: Plastic In, Power + Slag Out
The complete material path from ocean to output, showing every handoff between subsystems.
1.1 Primary Process Flow (Bow-to-Stern, Left-to-Right)
OCEAN OUTPUTS
| |
v v
[Boom/Drone] --> [Receiving] --> [Pre-Process] --> [PRRS] --> [Syngas Train] --> [Engine] --> ELECTRICITY
Collection Deck Line Reactor Gas Cleanup Genset (powers ship)
(stern/side) (stern) (mid-aft) (midship) (midship) (midship)
| | |
v v v
[Slag] [Scrubber [Exhaust
Hold Waste] Stack]
(below (hazmat (above
deck) tank) processing)
1.2 Detailed Handoff Chain (12 Steps)
| Step | From | To | Interface | Physical Connection |
|---|---|---|---|---|
| 1 | Ocean | Boom system | Water surface | 200-600m V-boom, 1-3m draft, towed or deployed from stern |
| 2 | Boom | Receiving deck | Boom recovery | Stern ramp or side conveyor. Hydraulic winch pulls boom codend to deck. Debris + seawater deposited in receiving hopper |
| 3 | Receiving hopper | Freshwater rinse | Gravity feed | Hopper drains seawater through grated floor. Overhead spray bar rinses salt. Runoff to process water system |
| 4 | Rinse station | Shredder | Conveyor belt | 600mm wide belt conveyor, 2-5m run, variable speed. Manual sorting station inline for oversized items (large nets pre-cut by crew) |
| 5 | Shredder | Dewatering | Conveyor/chute | Shredded output (50-100mm fragments) drops into dewatering centrifuge or screw press. Moisture reduced from 50-70% to 15-25% |
| 6 | Dewatering | Feed hopper | Screw conveyor | Enclosed screw conveyor, 3-5m run, delivers de-watered shredded feedstock to reactor feed hopper. 24-48 hour buffer capacity in hopper (decouples collection from processing) |
| 7 | Feed hopper | PRRS reactor | Sealed feed system | Ram feeder or screw injector pushes feedstock into reactor chamber. Air-locked to prevent syngas backflow. Continuous feed at 0.2-0.4 tonnes/hour |
| 8 | PRRS reactor | Syngas cleanup | Insulated pipe | Hot syngas exits reactor at 800-1,100C. Rapid water quench (<0.5 seconds) drops to <100C. 200mm diameter insulated pipe, 5-10m run to cleanup train |
| 9 | Syngas cleanup | Syngas buffer | Steel pipe | Clean, cool syngas at ~50C. Composition: H2 48-53%, CO 24-28%. Passes through cyclone, scrubber, carbon bed, cooler, moisture separator. Exits to 50m3 buffer tank at low pressure |
| 10 | Syngas buffer | Gas engine | Steel pipe | Regulated gas supply to Jenbacher J620 GS or equivalent. 150mm pipe, pressure-regulated, with flame arrestor at engine inlet |
| 11 | PRRS reactor | Slag hold | Gravity chute | Molten slag tapped from reactor bottom, water-quenched to granulate, conveyed to below-deck hold via enclosed chute. 100-300 kg/day |
| 12 | Gas engine | Ship electrical bus | Cable | 2-3 MW output at 6.6 kV or 440V, synchronized to ship main switchboard |
1.3 Secondary Flows
Process water loop: Rinse water + dewatering effluent + quench water + scrubber blowdown --> process water treatment (oil/water separator, filtration, pH adjustment) --> recirculation to rinse station and quench system. Makeup from RO watermaker. Zero overboard discharge.
Waste heat recovery: Reactor shell radiation + syngas sensible heat + engine exhaust heat --> ORC (Organic Rankine Cycle) evaporator --> additional 50-100 kW electricity + feedstock thermal drying. The ORC is the key patent (US 9,447,705) that makes the energy loop close.
Scrubber waste: HCl scrubber (from PVC content ~5% of feedstock) produces acidic waste water with dissolved chlorides. Neutralized with caustic soda, stored in dedicated hazmat tank (below deck, double-walled), offloaded at port. Volume: ~0.5-1.0 m3/day.
2. Interface Specifications
The interfaces between subsystems are where integration failures happen. Each interface has mechanical, electrical, control, and safety requirements.
2.1 Collection-to-Processing Interface (CRITICAL -- least mature)
Physical location: Stern deck, transition from open collection area to enclosed pre-processing area.
Mechanical interface:
- Boom codend lifted by 25-40 tonne SWL crane onto receiving hopper
- Hopper: 5m x 3m x 2m, steel construction, grated floor for drainage
- Debris falls by gravity into rinse zone
- Large debris (ghost nets > 2m) requires manual pre-cutting before shredder
- Two-person crew station for manual sorting and oversized removal
Interface requirement: The receiving hopper and pre-processing line must handle:
- Debris pieces from 1mm (microplastic) to 5m+ (ghost net tangles)
- 50-70% moisture content
- Marine organism bycatch (crabs, fish, seaweed) -- must be sorted out before shredding
- Occasional non-plastic debris (metal, wood, rope) -- must be diverted
- Hydraulic grapple on crane for net handling
- Vibrating screen to separate fine debris from large items
- Manual sorting conveyor (slow speed, 0.2 m/s, crew on each side)
- Pre-cutting station: hydraulic shears for net bundles
- Magnetic separator for ferrous metals
- Metal detector on conveyor before shredder
2.2 Reactor-to-Syngas Interface
Physical location: Processing core, midship.
Mechanical interface:
- Syngas exits reactor at 800-1,100C through refractory-lined exit port
- Immediate water quench chamber (<0.5 second residence time) -- this prevents dioxin/furan formation
- Quench chamber produces steam + cooled syngas at <100C
- Quenched gas enters cyclone separator (removes particulates)
- Then wet scrubber (removes HCl, trace metals)
- Then activated carbon bed (removes remaining organics)
- Then gas cooler (drops to ~50C)
- Then moisture separator (removes water droplets)
- Then syngas buffer tank (50 m3, low pressure)
- Reactor exit to quench: 200mm bore, Inconel 625 or equivalent high-temperature alloy, < 2m length (minimize hot gas residence time)
- Quench to cyclone: 250mm bore, stainless steel 316L, insulated
- Cyclone to scrubber: 250mm bore, SS316L or FRP (fiberglass reinforced plastic)
- Scrubber to carbon bed: 200mm bore, SS316L
- Carbon bed to cooler: 150mm bore, SS316L
- Cooler to separator: 150mm bore, SS316L
- Separator to buffer tank: 150mm bore, carbon steel (gas is clean at this point)
- Buffer tank to engine: 150mm bore, carbon steel, with flame arrestor, pressure regulator, and emergency vent
- Gas composition analyzer after cleanup train (continuous H2, CO, CH4 monitoring)
- Pressure/temperature sensors at each stage
- Emergency vent to atmosphere (through flame arrestor) if syngas quality is off-spec
- Automatic shutdown if H2S > 50 ppm or HCl > 10 ppm at engine inlet
2.3 Engine-to-Ship Electrical Interface
Physical location: Processing core / engine room boundary.
Electrical interface:
- Syngas engine: Jenbacher J620 GS, 2-3 MW output
- Generator: synchronous, 6.6 kV or 440V (depends on ship bus voltage)
- Synchronization: automatic sync panel connects syngas genset to main bus
- Diesel backup gensets remain on main bus for redundancy
- Shore power connection retained for port operations
- Automatic bus transfer switch (< 0.5 second transfer)
- Load sharing controller
- Reverse power relay (prevents syngas genset from motoring if gas supply drops)
- UPS for critical systems (navigation, comms, fire/gas detection): 30-minute battery backup minimum
2.4 Slag Handling Interface
Physical location: Below reactor, through deck penetration to cargo hold.
Mechanical interface:
- Molten slag exits reactor bottom via gravity tap
- Water granulation: molten slag drops into water bath, shatters into granules (2-10mm)
- Granulated slag + water pumped via slurry pipe to dewatering screen
- Dry granules drop into below-deck hold via enclosed chute through deck penetration
- Hold: repurposed cargo tank, no special coating needed (slag is inert)
Deck penetration: The slag chute passes through the main deck into the hold below. This penetration must be:
- Weathertight (prevents seawater ingress)
- Fire-rated (H-120 minimum -- molten material above, cargo hold below)
- Structurally reinforced (local deck stiffening around penetration)
- Accessible for maintenance (removable cover/hatch)
3. Electrical Architecture
3.1 Single-Line Diagram (Conceptual)
MAIN SWITCHBOARD (440V/6.6kV)
____________|____________
| | |
[Syngas Genset] [Diesel G1] [Diesel G2]
2-3 MW (primary) 1 MW (backup) 1 MW (emergency)
|
_______________|________________
| | | |
[Process] [Collection] [Hotel] [Propulsion]
Bus Bus Bus Bus
| | | |
Reactor Cranes HVAC Main Engine
Cleanup Conveyors Lighting Bow Thruster
Shredder Winches Galley
Pumps Sensors Comms
Navigation
3.2 Power Distribution
| Bus | Consumers | Peak Demand | Normal Demand | Priority |
|---|---|---|---|---|
| Process | PRRS torch (200-500 kW), APT (200 kW), cleanup train (30-50 kW), feed system (20-30 kW) | 780 kW | 550 kW | Critical -- loss means reactor shutdown |
| Collection | Cranes (150 kW intermittent), conveyors (30 kW), shredder (50-80 kW), dewatering (20-40 kW), boom winches (30 kW) | 330 kW | 150 kW | Important -- can pause without reactor impact |
| Hotel | HVAC (40-60 kW), lighting (20-30 kW), galley (30-50 kW), watermaker (15-25 kW), comms (15-25 kW), sewage (5-10 kW) | 200 kW | 150 kW | Essential -- life safety |
| Propulsion | Main engine (12-15 MW transit), bow thruster (500 kW), steering (30 kW) | 15,530 kW | 30 kW (station-keeping) | Transit only -- zero during processing |
3.3 Hazardous Area Classification
Syngas (H2 + CO) is flammable and toxic. The processing core must be classified per IEC 60079:
| Zone | Area | Equipment Requirement |
|---|---|---|
| Zone 0 | Inside reactor, syngas piping, buffer tank | Intrinsically safe only (not normally accessible) |
| Zone 1 | 3m radius around syngas equipment, gas cleanup train | Ex d (flameproof) or Ex e (increased safety) |
| Zone 2 | Processing deck generally, 5m from Zone 1 boundary | Ex n (non-sparking) |
| Non-hazardous | Accommodation, bridge, engine room (if separated by gas-tight bulkhead) | Standard equipment |
Ventilation: Processing deck is open (natural ventilation) wherever possible. Enclosed spaces within processing area have forced ventilation with independent fans, interlocked to gas detection. Minimum 12 air changes per hour in enclosed processing spaces.
4. Thermal Integration
The Claw generates significant waste heat. Capturing it improves energy efficiency and reduces cooling requirements.
4.1 Heat Sources
| Source | Temperature | Thermal Output | Currently Wasted? |
|---|---|---|---|
| Reactor shell radiation | 200-400C (outer shell) | 50-150 kW thermal | Yes |
| Syngas sensible heat (pre-quench) | 800-1,100C | 200-400 kW thermal | Partially captured in quench |
| Engine exhaust | 400-500C | 300-600 kW thermal | Yes |
| Engine jacket cooling | 80-90C | 200-400 kW thermal | Yes |
| ORC condenser reject | 30-50C | 100-200 kW thermal | Yes (low grade, limited use) |
4.2 Heat Sinks (Useful Applications)
| Application | Temperature Needed | Heat Required | Source Match |
|---|---|---|---|
| Feedstock thermal drying | 80-120C | 100-300 kW | Engine jacket water or reactor shell |
| Freshwater (RO preheat) | 25-35C | 10-20 kW | ORC condenser reject |
| Accommodation heating | 20-25C | 20-40 kW | ORC condenser reject |
| Process water heating | 40-60C | 20-50 kW | Engine jacket water |
| ORC working fluid | 150-300C | 200-500 kW | Engine exhaust + reactor shell (THIS IS THE KEY RECOVERY) |
4.3 ORC Integration (Patent US 9,447,705)
The Organic Rankine Cycle recovers waste heat from the engine exhaust and reactor shell to generate additional electricity:
Engine exhaust (450C) ──> ORC evaporator ──> Working fluid vaporizes
|
Reactor shell (300C) ──> ORC evaporator ──> v
ORC turbine ──> Generator (50-100 kW)
|
v
ORC condenser ──> Seawater cooling
|
Pump ──> back to evaporator
ORC working fluid: R245fa or similar low-boiling-point organic fluid (boils at ~15C at atmospheric, operates at elevated pressure).
ORC location: Adjacent to engine and reactor, within processing core. Footprint: ~20-30 m2. Weight: ~5-10 tonnes.
The ORC is what makes the energy loop close at 5 TPD. Without it, the net energy surplus is marginal or negative at low throughput. With it, an additional 50-100 kW pushes the balance positive.
4.4 Cooling System
Seawater cooling is the primary heat rejection path. The GPGP surface water temperature is 18-24C (subtropical), providing an excellent cold sink.
- Engine cooling: seawater-to-freshwater heat exchanger (standard marine)
- ORC condenser: seawater-cooled (direct or via intermediate loop)
- Syngas cooler: seawater-cooled
- HVAC condenser: seawater-cooled
Seawater intake: existing tanker sea chest (hull-mounted intake), filtered. No modification needed. Discharge: overboard (heated seawater only -- no chemical contamination from cooling loop).
5. Control System Architecture
5.1 Distributed Control System (DCS)
The vessel needs an integrated control system that manages processing, power, and marine systems.
MAIN CONTROL ROOM
(Bridge Extension)
|
[DCS Server]
_____________|_____________
| | |
[Processing [Power [Marine
Controller] Controller] Controller]
| | |
- Reactor - Syngas - Navigation
- Feed system genset - Ballast
- Cleanup train - Diesel - Steering
- Shredder gensets - Fire/gas
- Dewatering - UPS - Comms
- Slag handling - Load shed - HVAC
- Collection - Shore power - Bilge
5.2 Automation Level
| System | Automation Level | Human Role |
|---|---|---|
| Reactor temperature control | Fully automatic (PID loop) | Monitor, adjust setpoints |
| Feed rate | Semi-automatic (operator adjusts based on feedstock quality) | Set rate, watch for jams |
| Syngas cleanup | Fully automatic | Monitor gas quality |
| Power management | Fully automatic (load sharing, bus transfer) | Monitor |
| Collection/boom | Manual with powered assists | Crane operator, deck crew |
| Pre-processing | Semi-automatic (conveyors auto, sorting manual) | Manual sorting, shredder feed supervision |
| Slag tapping | Semi-automatic (timed tap, auto granulation) | Monitor |
| Navigation | Autopilot with manual override | Watch officer |
| Emergency shutdown | Fully automatic (gas detection, overpressure, fire) | Initiate manual ESD if needed |
5.3 Emergency Shutdown (ESD) System
Independent from DCS (hardwired, fail-safe). Three ESD levels:
| Level | Trigger | Action |
|---|---|---|
| ESD-1 (Process) | Gas detection 40% LEL, reactor overpressure, syngas quality off-spec | Stop feed, extinguish plasma arc, close syngas isolation valves, vent syngas through flame arrestor, maintain cooling |
| ESD-2 (Plant) | Fire in processing area, multiple gas alarms, loss of cooling | ESD-1 + trip syngas engine, start diesel genset, isolate processing area ventilation, activate fire suppression |
| ESD-3 (Abandon) | Uncontrollable fire, structural failure, vessel emergency | ESD-2 + general alarm, muster stations, prepare lifeboats |
6. General Arrangement: Plan Views
6.1 Main Deck Plan (Top View)
BOW STERN
| |
| [HELIPAD] [ACCOMMODATION] [PROCESSING CORE] [COLLECTION] [BRIDGE]
| 26m dia 3-4 deck block Reactor + Syngas + Receiving Super-
| + HRF Cabins, galley, Engine + ORC + hopper, structure
| + foam medical, rec, Cleanup train + rinse, Nav,
| + fuel workshop below Buffer tank + sort, Ops center
| Fire wall (A-60) → Exhaust stack shredder, Radio
| Fire wall (H-120) → dewater, GMDSS
| ~30m ~45m ~80m crane(s) ~30m
| ~60m
| PORT SIDE: Lifeboat station, pipe rack, walkway (3m min clearance)
| STARBOARD SIDE: Lifeboat station, pipe rack, walkway (3m min clearance)
|
Key design decisions:
- Processing core is midship (best motion characteristics -- least pitch/roll acceleration)
- Collection is aft (boom deploys from stern, crane access to water)
- Accommodation is forward (upwind of processing exhaust in prevailing trade winds)
- Helipad at bow (furthest from hot exhaust and collection operations)
- Bridge at stern superstructure (sightlines to collection operations)
- Fire walls separate each zone: A-60 between accommodation and processing, H-120 between processing and collection (H-120 because hot slag/reactor side faces collection)
6.2 Below-Deck Tank Arrangement
BOW STERN
| |
| [Ballast] [Fresh ] [Ballast] [Feed- ] [Slag ] [Ballast] [Diesel] [Ballast]
| Wing Water Wing stock Hold Wing Storage Wing
| tanks 2,000- tanks Buffer 3,000- tanks 500- tanks
| (P+S) 3,000 m3 (P+S) 2,000- 6,000 (P+S) 1,000 m3 (P+S)
| 4,000 m3 m3
| [Ballast] [Methanol] [Ballast] [Ballast] [Ballast] [Hazmat] [Slop/Sewage]
| Center 1,000- Center Center Center 500- 500 m3
| 2,000 m3 1,000 m3
| (Phase 1.5)
Tank assignment rationale:
- Ballast in wing tanks: Standard tanker practice. Active ballast management compensates for changing topsides weight as feedstock is consumed and slag accumulates
- Freshwater midship: Central location for distribution to accommodation (fwd) and processing (mid)
- Feedstock buffer mid-aft: Close to collection deck (aft) and reactor (midship). Enclosed screw conveyor connects to reactor feed hopper above
- Slag hold midship: Directly below reactor for gravity-fed slag chute. Shortest possible path for molten slag handling
- Methanol center tank (Phase 1.5): Amidships for stability. Double-hull protection required per IBC Code. N2 blanket system, cofferdams on all sides
- Diesel aft: Close to engine room. Standard tanker fuel tank location
- Hazmat aft: Scrubber waste, contaminated process water. Small volume, double-walled, segregated
6.3 Processing Core Detail (Expanded View)
PROCESSING CORE (~80m x 40m)
PORT STARBOARD
| |
| [Pipe [Syngas [PRRS [Feed [Pipe |
| rack] Cleanup Reactor Hopper rack] |
| Train] + Stack + Ram |
| Cyclone Feeder] |
| Scrubber |
| Carbon bed |
| Cooler |
| Separator] |
| |
| [ORC [Syngas [Jenbacher [Slag [Elec- |
| Module] Buffer Gas Engine Granu- trical |
| Tank + Generator lation Switch |
| 50 m3] 2-3 MW] + Chute] room] |
| |
| 3m egress walkway on both sides |
Equipment arrangement logic:
- Reactor centrally located (heaviest item, best stability position)
- Feed hopper adjacent to reactor (shortest possible feed path)
- Syngas cleanup train inline from reactor exit (minimize hot gas piping length)
- Buffer tank between cleanup and engine (decouples gas production from consumption)
- Engine adjacent to electrical switchroom (shortest cable run for heavy power)
- ORC module between reactor and engine (captures waste heat from both)
- Slag granulation directly below reactor (gravity-fed through deck penetration)
- Pipe racks on both port and starboard for syngas, process water, cooling water, instrument air
7. Conversion Sequence: Shipyard Order of Operations
The conversion takes 24-36 months. The sequence matters -- some work must happen before other work can begin.
Phase 1: Strip-Out & Survey (Months 1-4)
| Month | Work | Notes |
|---|---|---|
| 1 | Vessel arrives at conversion yard. Drydock for hull survey | Full thickness measurement, ultrasonic testing, classification surveyor present |
| 1-2 | Strip cargo systems: pumps, piping, COW, IGS, heating coils | 500-800 tonnes removed. Hazmat survey (asbestos in old insulation) |
| 2-3 | Tank cleaning and gas-freeing. Internal inspection of all cargo tanks | Hydrocarbon residue removal. Decide which tanks need recoating |
| 3-4 | Stability calculation with new loading condition (preliminary) | Naval architect runs intact + damage stability with estimated topsides weight |
| 4 | Scope confirmation meeting with classification society | Final strip-out complete. Yard, designer, class agree on conversion scope |
Phase 2: Structural Modifications (Months 4-12)
| Month | Work | Notes |
|---|---|---|
| 4-6 | Deck reinforcement: new stiffeners, pillar supports through to tank top | 800-1,200 tonnes new steel. Hot work permits, confined space entry |
| 5-7 | Reactor foundation: grillage, thermal isolation, secondary containment | 80-120 tonnes. Heaviest single foundation on the vessel |
| 6-8 | Bulkheads and fire walls: A-60 between zones, H-120 around processing | 300-500 tonnes. Must be gas-tight where separating hazardous areas |
| 7-9 | Crane pedestals (2x), helipad structure, accommodation extension | Crane bases need deep foundations to hull structure |
| 8-10 | Exhaust stack structure, pipe rack foundations, equipment stools | All major steel complete by month 10 |
| 10-12 | Hull repairs (as identified in survey), recoating, anode replacement | Drydock work if needed |
Phase 3: Equipment Installation (Months 10-22)
| Month | Work | Notes |
|---|---|---|
| 10-12 | Crane installation. Heavy lift required for 25-40 tonne SWL cranes | Yard crane or floating crane |
| 12-14 | PRRS reactor module delivery and installation | Heaviest single lift (80-150 tonnes). Must be lifted over side and set on foundation. Alignment critical |
| 13-15 | Syngas cleanup train installation (cyclone, scrubber, carbon bed, cooler) | Modular -- can be pre-assembled at manufacturer then shipped as skid |
| 14-16 | Jenbacher gas engine + generator installation | Engine room modification. Vibration mounts, exhaust routing, cooling connections |
| 15-17 | ORC module installation | Adjacent to engine. Thermal connections to engine exhaust and reactor shell |
| 16-18 | Collection equipment: boom winches, conveyors, shredder, dewatering | Stern area. Can proceed independent of processing core installation |
| 17-19 | Electrical: new switchboard, cable pulls, motor connections, lighting | Thousands of meters of cable. Hazardous area equipment installation |
| 18-20 | Piping: syngas, process water, cooling water, fire main, instrument air | Major piping campaign. Hydrostatic testing of all process piping |
| 19-21 | Instrumentation: DCS, gas detection, fire detection, ESD system | Control room fit-out. Loop testing of every instrument |
| 20-22 | Accommodation fit-out: cabins, galley, medical bay, recreation | Can proceed parallel to processing installation |
| 21-22 | Helipad: deck surfacing, lighting, foam system, fuel system | Late installation to avoid damage during construction |
Phase 4: Commissioning & Testing (Months 22-28)
| Month | Work | Notes |
|---|---|---|
| 22-23 | Mechanical completion. Punch list. | Walk-through every system, identify incomplete items |
| 23-24 | Cold commissioning: run all systems without feedstock/plasma | Pump tests, valve stroke tests, electrical load tests, control system verification |
| 24-25 | Hot commissioning: first plasma ignition, first syngas production | PyroGenesis engineers on board. Controlled feedstock (clean plastic pellets, not ocean debris) |
| 25-26 | Performance testing: energy balance verification, throughput test | Run at design rate for 48-72 hours continuous. Measure everything |
| 26-27 | Inclining experiment and stability verification | Required by classification society. Confirms actual vs. predicted stability |
| 27-28 | Sea trials: 3-5 days at sea. Full system testing underway | Navigation, propulsion, station-keeping, collection system deployment, processing at sea |
| 28 | Classification certificate issued. Flag state registration | Vessel officially approved for operations |
8. Combined Weight & Stability Analysis
8.1 Weight Budget
Consolidating equipment weights from all subsystem research:
| Item | Weight (tonnes) | Source Doc | CG Height Above Keel (m) |
|---|---|---|---|
| Lightship (stripped tanker) | 14,000-16,000 | Hull selection | ~9.5 (standard Aframax) |
| New structural steel | 1,800-2,700 | Retrofit engineering | ~14 (deck level) |
| PRRS reactor module | 80-150 | PRRS deep dive | ~16 (on main deck) |
| Syngas cleanup train | 54-103 | Syngas / retrofit | ~16 |
| Gas engine + generator | 85-100 | Retrofit engineering | ~8 (engine room level) |
| ORC module | 5-10 | This document | ~15 |
| Cranes (2x) | 60-80 | Retrofit engineering | ~18 (above deck) |
| Collection equipment | 50-80 | Collection systems | ~15 |
| Helipad structure | 80-120 | Internal layout | ~18 (elevated) |
| Accommodation extension | 100-200 | Retrofit engineering | ~20 (multi-deck) |
| Piping + electrical | 100-200 | Retrofit engineering | ~12 (distributed) |
| Misc (coatings, furniture, outfit) | 50-100 | Estimate | ~12 |
| TOTAL TOPSIDES | 2,464-3,843 | Combined | ~14.5 (weighted avg) |
8.2 Deadweight Items (Variable)
| Item | Weight (tonnes) | CG Above Keel (m) |
|---|---|---|
| Ballast water | 25,000-40,000 | ~5 (low, in double bottom and wing tanks) |
| Diesel fuel | 400-800 | ~6 |
| Freshwater | 2,000-3,000 | ~6 |
| Feedstock buffer | 0-2,000 | ~6 (in cargo tank) |
| Slag (accumulated) | 0-500 | ~5 (below deck) |
| Methanol (Phase 1.5) | 0-200 | ~6 |
| Provisions/stores | 50-100 | ~12 |
| Crew + effects | 5-10 | ~15 |
8.3 Stability Assessment
Key metric: GM (metacentric height)
An Aframax tanker has GM of 2-5m in various loading conditions. Adding ~2,500-3,800 tonnes of topsides at ~14.5m CG height raises the overall KG (center of gravity).
Preliminary estimate (from internal layout doc): KG ~6.6m with topsides installed. This is LOW and favorable -- the heavy ballast water in low tanks keeps the CG well below the metacenter.
Stability is not a limiting factor. The vessel started as a tanker designed to carry 80,000-120,000 tonnes of crude oil at a high CG. The topsides equipment is ~3% of the original cargo weight. Ballast management provides ample margin.
What DOES matter: asymmetric loading. If feedstock accumulates on one side, or a crane lifts a heavy load to one side, the vessel lists. Active ballast management (automatic ballast transfer to compensate for list) is essential.
9. Critical Integration Risks
| Risk | Impact | Mitigation |
|---|---|---|
| PRRS dimensions differ from estimates | Foundation doesn't fit, piping runs change | Get exact dims from PyroGenesis during FEED. Foundation design uses maximum envelope + 15% margin |
| Syngas composition varies with feedstock mix | Engine detonation, cleanup train overload | Gas composition analyzer before engine. Automatic feed rate adjustment. Conservative engine tuning |
| Collection interface doesn't handle net tangles | Processing starved, crew overworked at manual sorting | Size pre-cutting station for worst case. Budget for 2-person sorting crew per watch |
| Electrical load exceeds generation at 5 TPD | Must run diesel backup, breaks self-power narrative | Design for 10 TPD capacity, accept that 5 TPD may need diesel assist. ORC recovery is critical at low throughput |
| Vibration from processing equipment affects navigation/accommodation | Crew fatigue, instrument calibration drift | Vibration isolation mounts on all major rotating equipment. Vibration survey during commissioning |
| Thermal expansion of reactor piping | Pipe stress, flange leaks, syngas release | Expansion bellows, sliding supports, proper pipe stress analysis during detailed design |
| Hot work near syngas systems during maintenance | Fire/explosion risk | Comprehensive hot work permit system. Gas-free certification before any hot work. Never do hot work while reactor is operating |
10. What FEED Must Resolve
The Front End Engineering Design (FEED) phase turns this conceptual design into an engineering specification. These items cannot be resolved without FEED:
1. Exact PRRS reactor dimensions and weight -- from PyroGenesis, after PoC results confirm technology selection 2. Specific hull selection -- hull condition determines structural modification scope 3. Syngas composition from actual ocean plastic -- from PoC Stage 2, determines engine selection and cleanup train sizing 4. Classification society requirements -- from AiP process, may drive design changes 5. Shipyard-specific constraints -- crane capacity, drydock dimensions, labor availability 6. Detailed pipe stress analysis -- thermal expansion, vibration, ship motion 7. Finite element analysis -- hull structure under combined loading (topsides + wave + mooring) 8. Electrical load study -- actual equipment specifications, cable sizing, short circuit analysis 9. HAZOP study -- systematic identification of process hazards, required for classification approval 10. Escape route analysis -- fire safety engineering, mustering routes, lifeboat access from all locations
Summary
This document provides the systems-level integration view that connects the subsystem research into a unified ship design. Key takeaways:
1. 12-step process flow from ocean to output, with every handoff specified 2. 4 critical interfaces defined: collection-to-processing (least mature), reactor-to-syngas, engine-to-electrical, slag handling 3. Electrical architecture with load shedding priority and hazardous area classification 4. Thermal integration recovers ~850-1,750 kW waste heat; ORC is the key to closing the energy loop at 5 TPD 5. 28-month conversion sequence (optimistic) with 4 phases and critical path through PRRS procurement 6. Combined weight budget shows ~2,500-3,800 tonnes topsides on a ship designed for 80,000-120,000 tonnes cargo. Stability is not a concern 7. 10 FEED items that must be resolved with actual equipment data before detailed design can proceed
The collection-to-processing interface is the least mature element. Everything else has industrial precedent (FPSO conversion, PAWDS marine plasma, syngas engines). The integration challenge is engineering, not invention.
Research compiled March 2026. Integrates content from 10 existing knowledge tree documents (nodes 6, 7, 22, 46, 54, 55, 56, 58, 65) into a unified vessel design view. No subsystem detail is duplicated -- this document covers only interfaces, integration, sequence, and combined analysis.