FID Injector – Water-Fuel Emulsion for Marine Engines

How the FID Injector Works with Water-Fuel Emulsions

A controlled quantity of water is introduced into the fuel stream. Inside the homogenizer, high shear forces disperse the water as fine droplets throughout the fuel, producing a uniform emulsion for delivery to the engine.

During combustion, the water absorbs heat as it vaporizes, helping reduce peak combustion temperatures and NOx formation. The emulsion also supports fuel breakup and mixing during combustion, reducing soot and unburned material.

The process uses mechanical treatment without requiring emulsifying additives.

Installation Before the Engine Circulation System

The FID Injector is typically installed between the booster feed pump and the mixing tank, before the engine circulation system. This places controlled water addition and emulsification in the fuel feed to the circulation loop.

The arrangement includes fuel-flow measurement, a dedicated water supply and dosing system, and the homogenizer. Final integration is coordinated with the existing pumps, mixing tank, heaters, filters and engine controls.

Controlled Water Dosing

The Injector Plus configuration uses Emerson Coriolis mass flow measurement and PLC-controlled water injection to monitor fuel and water flows and regulate the selected water addition.

The system can accommodate water addition up to 20%, with the operating setting selected for the engine, fuel and load conditions. The maximum setting is not the recommended setting for every operating point.

Engine injection timing and control strategy are considered when selecting the water-dosing programme and evaluating the benefit of emulsification.

Fuel Savings and Emission Reduction

IPCO Power reports the following performance figures for HFO water-fuel emulsion applications:

Reported performance

Fuel saving — four-stroke engines: Up to 2%

Fuel saving — two-stroke engines: Up to 3%

NOx reduction: Up to 20%

Particulate matter reduction: Up to 90%

Results depend on the engine, fuel, load and water-dosing setting. These figures describe different performance measures and should not be assumed to occur simultaneously at every operating point.

Lower soot and particulate formation supports cleaner combustion chambers and exhaust systems and can reduce the soot burden on downstream scrubbers. Lower fuel consumption also reduces associated CO₂ emissions at comparable engine output.

When evaluating fuel savings, compare the mass of fuel consumed for equivalent output, excluding the added water. Include system power consumption when calculating the net operational saving.

Planning a Water-Fuel Emulsion Installation

Which fuels and engines is the FID Injector intended for?

The documented Injector Plus configuration is intended for HFO applications. Engine suitability is assessed from the engine type, injection equipment, operating loads and control strategy. These details determine the proposed water-dosing programme and installation arrangement.

What water percentage should be used?

The appropriate setting depends on the engine and operating objective. Water addition is selected and evaluated under the relevant load conditions, with fuel consumption, emissions and engine performance assessed together. The maximum dosing capability is not a universal operating recommendation.

How does water-fuel emulsification differ from homogenization alone?

Homogenization alone conditions the fuel without deliberately adding water. Water-fuel emulsification adds a controlled quantity of water and disperses it through the fuel to influence combustion and emissions.

The preferred mode depends on the engine and its injection and control strategy. For some engine configurations, homogenization without water is the more effective approach.

Does the FID Injector add value if my vessel already has a scrubber?

Yes. A conventional SOx scrubber treats exhaust gases after combustion. The FID Injector acts before combustion, improving fuel efficiency and reducing the formation of NOx, soot and particulate matter.

Less soot entering the scrubber can reduce the particulate load in its washwater. In closed-loop operation, this can also ease the load on the water treatment system and reduce soot-derived sludge.

The technologies therefore complement each other: the scrubber controls sulphur emissions, while the FID Injector improves combustion at source. The additional benefits depend on the engine, fuel and scrubber operating conditions.

FID Injector Specifications

Application: Water-in-fuel emulsification for HFO

Homogenizer: High-shear vertical rotor–stator design

Housing: Aluminum 7075-T6 with proprietary hard-coat protection

Coupling: Magnetic coupling; no mechanical seals

Homogenizing chamber: Self-lubricating

Water dosing: Integrated high-pressure water pump and PLC control

Flow measurement: Emerson Coriolis mass flow meters

Standard listed capacities: 4,500 / 9,000 / 12,000 l/h

Maximum pressure: 12 bar

Minimum HFO temperature: 90°C

Main power options: 400 / 440 / 460 / 690 V

Control-panel supply: 230 V at 50 Hz / 250 V at 60 Hz

Protection class: IP54

Connections: DN50 and SAE flanges, as specified for the system

Frame finish: RAL 7016

Higher capacities are available on request. Final selection is based on the operating flow and required water-dosing duty.

Available interface connections include ship ESD signals, running and fault contacts, and a water-in-fuel percentage output. The interface arrangement is agreed for the installation.

Discuss Your Water-Fuel Emulsion Application

Send us your engine make and model, fuel details, operating load profile and fuel-system drawing. Include the fuel flow, temperature and pressure at the proposed installation point and details of the available water supply.

We will help assess the application, select the system capacity and define the water-dosing and control arrangement.