Environmental technology company Nano Bubble Technologies (NBT) says its emulsion fuels offer the boiler industry environmental and economic benefits.

NBT points out that a feature common to emulsion fuels is that they can be used with minimal service and maintenance requirements in boiler plants.

The company offers stable and cost-effec-tive fuel emulsions. The production of these emulsions involves the use of chemical additives, a mechanical blending process and technical know-how, ensuring that the emul- sions are stable throughout the working temperature and pressure range. The benefits of using emulsified fuels are derived only if the emulsified fuel remains stable immediately prior to combustion. NBT’s technologies reli- ably produce stable emulsified fuels of consis-tent quality and standard, says the company.

“Emulsions are inherently unstable. Over time, they will separate into the stable states of the dispersed and continuous-phase materials. “To maintain the composition of an emulsion, surface-active agents, or ‘surfactants’, are incorporated into the production of an oil-phased emulsion. In an oil-phased emulsion, these surfactant agents encase the droplets of water distributed throughout the continuous oil phase and prevent the water droplets from joining and coalescing,” says NBT depot sales manager Karl Henriksen.

NBT’s proprietary technology creates stable mixtures of emulsified fuels, which contain varying percentages of water content. The emulsion technology can be applied to bind various base fuels with water, creating an array of environment-friendly products that reduce both oxides of nitrogen (NOx) and particulate matter (PM) pollution created during the combustion process.
“Combustion occurs on the surface of each fuel droplet as the fuel is exposed to oxygen in the air. Larger fuel droplets do not combust completely, causing unburned fuel to escape as particulate matter in exhaust gases. This reduces overall thermal efficiency and increases harmful emissions.

“Unlike ordinary fuels, when emulsified fuel droplets are sprayed into the combustion chamber, a secondary atomisation occurs as a result of the violent transformation of the water droplets into steam. This transformation of water into steam shatters the petroleum surrounding the water particle into much smaller fuel droplets,” explains Henriksen.

NBT emulsified fuels are a blend of traditional liquid fuels such as diesel, paraffin, heavy-fuel oil or biodiesel and water. The water is present as droplets of about 2 µm, which are distributed throughout the base fuel. The emulsion is known as an oil-phase emulsion. As a result, the finished emulsion has many of the physical characteristics of its base fuel.

Emulsion technology better atomises fuel through the vaporisation of water, allowing for a cooler and more complete combustion. In diesel- or biodiesel-based emulsions, extremely small water particles are entrained in the base fuel through a high-shear blending process that employs an additive to bind the water and fuel in a stable emulsion. Emulsions are the only fuel that simultaneously reduces both NOx and PM emissions.