500-200000 DWT 200-3000t/h Rail Mobile Screw Coal Ship Unloader

AOTUO Rail Mobile Screw Coal Ship Unloader: Product Positioning

This rail mobile screw coal ship unloader is a continuous, fully enclosed coal unloading machine. AOTUO developed and applied the first unit to a power plant coal transport system in China in 2018. The machine uses a rail-mounted bogie to move between berths, a rotating tower for horizontal positioning, and a vertical screw arm to feed coal into the horizontal screw conveyor and then to the shore conveying system.

The design is aimed at coal handling where dust control, high availability and low energy cost per ton matter. The screw conveying path is closed from intake to discharge, so coal is not dropped through open air. The rail-mounted configuration lets one machine serve multiple berths, which suits terminals with changing vessel sizes and berth allocation.

Technical Specifications and Operating Boundaries

Capacity is calculated on coal bulk density of 0.8 to 1.1 t/m³. Actual throughput depends on coal type, moisture, angle of repose and hold geometry. The table below summarises the main parameters we confirm at proposal stage.

Coal Handling Design Features

Coal is abrasive and often carries gangue and hard impurities. AOTUO applies an ultra-wear-resistant alloy layer to the intake and lower wear parts, with hardness up to 75 HRC. This extends the service life of the reclaimer and keeps the machine productive in high-wear coal service.

• Reinforced screw flighting: pitch-to-diameter ratio of 1.2, chrome carbide hardfacing (550-600 Brinell) on flighting edges and liner plates; optional tungsten carbide overlay for coal with HGI below 40.
• Large lump capability: tapered intake entry and grizzly bar section handle lump coal up to 400 mm and prevent oversize jamming.
• Variable frequency drive: main screw speed range 40-120 RPM, flow modulation from 20 to 100% capacity.
• Dust collection: closed conveying system with dry fog dust suppression and spark arrestor; dust emission controlled to 10 mg/m³.
• Rail mobility: four-point support bogie, transfer time between berths 5-8 minutes, track length typically 200-600 m.

Application Fit Across Coal Terminals

The rail mobile screw coal ship unloader fits coal export terminals, power plant coal receiving berths, multi-berth coal terminals, steel plant raw material yards and industrial boiler fuel terminals. It handles bituminous coal, sub-bituminous coal and lignite within the stated moisture and temperature limits.

For terminals that also handle cement, clinker or grain, AOTUO supplies related equipment such as the 1000-70000 DWT 200-1500t/h Rail mobile Screw Ship Unloader and the 300-1500t/h 800-50000DWT Rail Mobile Ship Loader For Loading Bulk Materials. Auxiliary equipment including dust collectors, belt conveyors and air slides can be integrated into the same transfer system.

Controls, Automation and Safety Integration

The unloader is delivered with a PLC-based control system, remote monitoring interface, production logging and maintenance alerts. The main screw is driven by a variable frequency drive for flow modulation. The control system can be configured around the required line interface, including the shore conveying system and the terminal's central control room.

Safety features for coal dust service include explosion venting panels per NFPA 68, spark detection sensors at the screw intake and discharge hopper with automatic shutdown, grounding straps for static discharge, and dust-ignition-protected electrical components (Class II, Division 2). Methane monitoring is available for coal with volatile matter above 35%.

Installation, Commissioning and Acceptance

Rail foundation requirements include rail gauge 6000-8000 mm, foundation load rating 35 tonnes per wheel, rail straightness tolerance ±3 mm over 10 m, and maximum gradient 0.3%. Power supply is 6600 V or 690 V, 50/60 Hz, three-phase, with cable reel or festoon system along the track.

Factory acceptance testing is carried out at 100% capacity with coal-simulant material. On-site commissioning includes a 12-hour continuous run test with actual coal and a load test to 110% of rated capacity. Operator training covers coal dust safety, explosion prevention, boom controls, emergency procedures and dust system monitoring.

Maintenance and Serviceability

Coal dust accumulation requires weekly inspection of the dust collection system and spark detection sensors. Screw flighting wear inspection is recommended every 400 operating hours for bituminous coal and 300 hours for sub-bituminous or lignite. Hardfacing replacement typically falls at 3000-4500 hours depending on coal abrasiveness. Dust filter bag replacement is every 18-24 months.

AOTUO provides spare parts supply, technical documentation and service support. The company operates a global service system with response commitments for installation, after-sales, operation and maintenance personnel.

Information We Use to Configure Your Solution

To prepare a configuration and quotation for a rail mobile screw coal ship unloader, we need the following project inputs. This list is not a purchasing checklist; it is the engineering data our team uses to size the machine and confirm the interface.

• Vessel range: minimum and maximum DWT, typical hatch sizes and freeboard heights.
• Coal properties: bulk density, lump size distribution, moisture content, HGI, volatile matter and temperature.
• Capacity target: required t/h, operating hours per day and annual throughput.
• Berth layout: number of berths to be served, rail track length, gauge and foundation conditions.
• Power supply: voltage, frequency and available installed power.
• Shore interface: receiving conveyor capacity, belt width and transfer point elevation.
• Environmental limits: dust emission target, noise limit and applicable local standards.
• Automation scope: central control interface, remote monitoring and data logging requirements.

Frequently Asked Questions

What is the maximum lump coal size the rail mobile screw coal ship unloader can handle?

The standard screw configuration handles lump coal up to 400 mm, with 90% passing a 400 mm screen. A grizzly bar section at the intake prevents oversize material above 450 mm from jamming the screw.

How does the rail-mounted design benefit a coal terminal?

A single rail-mounted unit can serve 2 to 5 berths, reducing equipment count by 30-50% compared with fixed unloaders. Transfer time between berths is 5-8 minutes, and track length typically ranges from 200 to 600 m depending on terminal layout.

What dust emission level does the unloader achieve?

The closed conveying system and dry fog dust suppression control dust emission to 10 mg/m³ or less at the stack outlet, meeting coal terminal environmental permit requirements.

What coal moisture content is acceptable?

The unloader handles up to 15% moisture for bituminous coal and up to 25% for sub-bituminous coal. Coal temperature can range from ambient to 60°C. Materials with HGI below 40 require upgraded wear protection.

How is capacity calculated for a specific project?

Capacity values are based on bituminous coal with bulk density of 0.85 t/m³, free-flowing condition, moisture below 8%, and lump size distribution 0-400 mm with 50% passing 100 mm. Actual throughput varies with coal type, moisture, angle of repose and hold geometry; reduction factors apply for high-moisture lignite or cohesive coals.

What safety features address coal dust explosion risks?

The dust collection system includes explosion venting panels per NFPA 68. Spark detection sensors at the screw intake and discharge hopper trigger automatic shutdown. Grounding straps prevent static discharge, and electrical components are dust-ignition protected (Class II, Division 2). Oxygen monitoring is optional for high-risk coals.