The Cavitronix™ E2C® Process For Marine Diesel Applications

Emulsion Fuels For Marine Applications

It has been reported that international shipping contributes almost 3% of total world carbon emission (from human sources). High combustion temperatures of modern marine engines and lack of after-treatment methods cause high global emissions of NOx. Thus, there has been considerable recent attention given to water-in-fuel emulsion (“WIF”) technology for marine diesel applications. A number of companies – large and small – are involved in potential applications of WIF in both diesel marine fuels and heavy oil fuels. Several studies have been conducted pointing to advantages for WIF – primarily on the environmental side – in marine applications.1 In fact, emulsion fuel technology has been around for over 60 years. To date, according to the European Committee for Standardization, emulsion fuels are the only fuels that simultaneously reduce emissions of, nitrogen oxides, particulates and carbon dioxide of diesel engines without the need for any mechanical modifications.2

The Challenge:

An emulsification technology applicable to the huge marine transportation field has been challenged by the need for a process which allows substantial quantities of water to be incorporated into the marine fuel without causing engine deterioration, loss of power or engine reliability. The primary current approach to this challenge has spawned a number of organizations and companies looking at chemically stabilized fuels with the “right emulsifying agent”.

As noted below, the Cavitronix approach is different – it does not use chemical surfactants or other stabilizing agents. CavitroniX has a growing presence in the emulsion fuel field. Our technology provides for just-in-time creation of WIF – to be used – only as needed. This distinguishes it from other providers of WIF.

The “E2C®” Emulsion Process:

An E2C® system for marine application does not require modification of existing engines. The E2C® unit(s) sit near the engine(s).

First, the water and oil are fed together proportionately into the specially designed Cavitational Blending Reactor™ (“CBR”) manifold intake manifold. The ratio of water to oil depends on the application, usually about 15 percent water and 85 percent oil. Once inside the reactor, the water and oil are subjected to hydrosonically generated cavitation which is continuous and controlled. As the cavitation bubbles grow and implode they bring about huge internal stresses in the liquid. This disruptive force causes the water particles to disperse inside the oil in the form of minute spheres. This process results in oil being the “continuous phase” and water being the “discontinuous phase”.

The emulsion, thus formed, flows from the CBR chamber into a delivery manifold and then to the atomizer or injector. The droplets of water absorb the heat as they near the flame and burst into super heated steam. The process literally blows apart the oil droplet in a phenomenon generally known as “microexplosions” or “secondary atomization”.3 The result is a substantial increase of the surface area of the oil exposed to the flame which then burns faster and more completely.

Field studies by CavitroniX, including tests run on diesel generators, automobile and marine engines, have demonstrated that when temperature spikes in the combustion process of No. 2 fuel oil are reduced by the presence of minute particles of water or water vapor at the point of maximum temperature, the formation of NOx is also dramatically reduced. It is CavitroniX’s expectation that similar results will occur when the E2C® process is applied to the combustion of heavy fuel oils which need to be heated in order to flow as required (Fuel Oils Nos. 4, 5, 6, Bunker-C).

E2C® unit controls can be located in the engine room, bridge or elsewhere on board as required. They can also be integrated into a vessel’s automated fuel control system.

Benefits of the CavitroniX Emulsion Process Expected in Marine Diesel Applications:

  1. Improved Net Efficiency. More even combustion temperatures apparently limit exhaust burning and boiler or engine overheating. Leaner ratios reduce carbon monoxide (CO) emissions. The presence of water yields a cleaner combustion chamber in a boiler and more expansive work in the power stroke per unit of fuel used in an engine.4 The reduced maximum combustion temperature spikes can also reduce cylinder wall losses. The net result is a smoother, cleaner, more efficient engine consuming less fuel.
  2. Reduced Emissions (reduced NOx and Particulates). The surface area of the oil is increased due to the rapid phase change of the added water wherein the surface areas of the oil is increased. The presence of some water in combustion means that dissociation temperatures are not fully realized, and NOx emissions are reduced significantly. It also reduces black smoke or exhaust and unburned carbon particles (depending on the combustion system and exhaust situation prior to installation of the CavitroniX E2C® equipment). CO2 is reduced by the burning of less fuel. It is expected that SOx emissions are also reduced. These benefits are especially relevant in view of ever tightening International Maritime Commission MARPOL emissions restrictions.
  3. Internally Cleaner Engine (no carbon buildup). During combustion, the internal water droplets vaporize, causing micro explosions of the fuel, leading to a much finer atomization and a very thorough mixing of air and fuel. This allows complete combustion with much less air and a dramatic reduction in carbon buildup. The reduced soot buildup on vital engine parts allows better heat transfer because soot buildup is an effective insulator that inhibits heat transfer.
  4. Reduced Back-End problems. Use of the E2C® process reduces back-end problems such as fouling – even when scrubbers, filters, bag houses or other mechanisms are used for environmental purposes.
  5. Cost Effectiveness. The cost of equipment and installation in most cases can be covered by the fuel savings achieved in one or two years depending on fuel cost and consumption. Economic savings can also be realized from expected reductions in engine maintenance, and likely useful life extension of existing engines.

Prior Testing:

Test results for marine emulsion fuel systems from other companies can be found on the web (search terms “marine emulsion fuels tests”). CavitroniX has conducted numerous tests of both the operation of the E2C® as an emulsifier of water and oil (utilizing No.2 diesel fuel oil) and as an effective methodology for reducing fuel consumption while also reducing harmful emissions. The tests have been undertaken at the CavitroniX Lab and in the field by CavitroniX at pilot installation sites on land and at sea.

According to the Danish EPA report, “engine tests devoted to mapping of the emission reduction potential of the WIF method effectively demonstrate that both NOx, CO and soot emissions are reduced when water is added to the injected fuel.” (Danish Report, p.17).

No tests have been conducted to date by CavitroniX at pilot sites or on vessels utilizing heavy fuel oils requiring heating in order to flow. CavitroniX recognizes the need for such tests and invites collaboration from appropriate resources. Other companies have claimed savings utilizing chemically stabilized fuels.5 It has yet to be demonstrated by the Company that similar, or even better, results in fuel savings and emissions reduction will occur when heavier, less viscous fuels are used via the E2C® surfactant-free emulsion fuel.

Conclusion:

It is the CavitroniX premise that an un-stabilized water in fuel emulsion is a better choice than chemically stabilized fuel emulsions for applications in engines and boilers where there is the opportunity to “make it and burn it” in real time as needed – without the challenges of transportation, storage and possible separation of water and oil, and possible contamination when chemical surfactants are used with chemically stabilized WIF.

Footnotes:

  1. See for example: “Water-in-fuel emulsion as marine engine fuel for reduced NOx and particulate emissions”. Danish Environmental Protection Agency Project No. 1380-2011. (the “Danish Report”). Note, the Danish Report and studies listed on the extensive bibliography reviewed and considered primarily chemically stabilized additives in WIF and/or stabilized emulsion fuels.
  2. CEN Workshop 19 “Water in diesel fuel emulsion for use in internal combustion engines”.
  3. Princeton Professor C.K. Law has written extensively on Oil-Water droplets and the chemistry and physics of oil-water emulsions – again, chemically stabilized. See, for example: C.K. Law “A Model for the Combustion of Oil Water Emulsion Droplets.” Combustion Science and Technology, 1977
  4. Cotefco/Cavitronix Technical Report January 2008, Note on Boiler Inspection and observation of tests in Gulf of Mexico on MV Ruby River (Trico Marine) by Charles Markert, CavitroniX Chief Engineer. The fuel utilized in these tests was No. 2.
  5. See, for example, claims at: www.Next-Alternative.com; www.quadrisefuels.com; www.altpetrol.com; and www.monohakobi.com.