Emulsion fuels target market acceptance
Driven by an increasing focus on costs and tightening emissions regulations, ship owners and fuel suppliers are accelerating the refinement and commercialisation of water-in-fuel emulsions. Dag Pike reports.
MSAR may sound like a respiratory disease, but it is in fact a second-generation fuel emulsion – the Multiphase Superfine Atomised Residue – that is about to start a practical test at sea. Developed by British company Quadrise, MSAR is the latest development in the quest to mix fuel and water in a practical fuel for diesel engines.
It has always been the practice at sea to keep water and fuel separate because it seems logical that any water in the fuel would stop the engine from running. However the concept of mixing oil and water has been under evaluation for many years now and the research is being spurred on by the demands to reduce emissions from diesel engines and from an economy point of view. Water is cheap compared with oil products and any dilution of the fuel with water would improve the economics of the operation - provided that efficiency can be maintained.
Just mixing fuel with water does not work. The mixture has to be fully emulsified so that each tiny drop of water is encased in a film of fuel. Several companies are working on the technology and how this is achieved tends to be a closely guarded commercial secret. When injected into the cylinder of a diesel engine the oil film ignites in the usual way under compression and the increase in temperature causes the water to turn into steam thus aiding the expansion process that drives the piston downwards.
During this combustion process the energy required in the conversion of the water droplets into steam helps to reduce the temperature of the gasses in the cylinder. This in turn reduces the amount of harmful emissions that are generated by the combustion process.
Some emulsions simply mix the existing fuel, diesel or HFO with the water immediately before injection. The heavy fuel oil that is commonly used for ships' bunkers tends to be the 'bottom of the barrel' , the dregs that are left over once all of the lighter, more volatile parts of the crude oil has been distilled off, leaving the very heavy oil as the remainder. For this to be used as the fuel for a diesel engine requires it to be mixed with some 'lighter' distillates such as kerosene in order for it to flow and to burn adequately. This adds to the cost of using this 'heavy' fuel so by using emulsions these heavy oils are made more liquid by the addition of water which of course is a cheaper alternative. To ensure that the mix of heavy oil and water achieves the right consistency some chemicals have to be added but even so it is forecast that once the production reaches a considerable quantity the overall cost will still be lower that that of current heavy fuel oils.
There is a long history of the benefits of adding water to the fuel of diesel engines. Some of the earliest experiments focussed on injecting water into the inlet manifold close to the point of fuel injection. This also works by cooling the temperature in the cylinder on ignition when the water is turned to steam, but it lacks the finesse of modern emulsion systems by being relatively hit and miss in the way that the burn is controlled. This water injection has been used as a way to reduce emissions from the engine.
Whilst oil in water emulsions have worked in laboratory testing it was left to the oil company BP, working with Petroleos de Venezuela, to develop the product on a commercial basis. The impetus behind this work was to find an application for the bitumen based residues from the crude oil of Venezuela. The product developed was Orimulsion which was aimed specifically at the power generation market and it was specifically banned from the ship bunker market. The first developments were in 1990 and four years later demand was exceeding supply.
Over 60 million tonnes was produced before a political decision led to the closure of the operation. Of particular note from this operation was the fact that the emulsion was stable and could be stored and transport by conventional means using the existing infrastructure.
Other smaller scale operations have been started with Green Odin in Hong Kong, developing emulsion fuels mainly for road transport, and in New Zealand Green Diesel converting used lubricating oil into a viable emulsion for use in diesel engines. Exomission in Germany is working on the technology for smaller diesel engines and in the US Alternative Petroleum technologies is following a similar path. Another producer of the systems and fuels in NanOil in Denmark. As far as can be established these all use systems that mix the emulsion immediately before injection.
Also in New Zealand the ferry Arahura is operating a trial using fuel oil emulsion technology in one of the ship's auxiliary engines. This fuel mix is a watered down version of diesel fuel that has been developed by Blended Fuel Solutions NZ. Arahura is a 148m long ferry built is 1983 and operates on the ferry service between the North and South islands in New Zealand. She is shortly due to be replaced by a new ferry.
"If these trials are successful it looks as though it could reduce our use of fuel and the level of emissions as well as offering a significant financial saving," said Malcom Sims, the engineer in charge of the project. "The trial will last for three months and it follows a two day trial back in 2013 which showed reduced fuel consumption and emissions, thus opening the way to this more extensive operational trial," Sims added.
Nonox in the US is more advanced with the application of emulsion technology on the marine side and they report that there are four ships fitted with their system and more to follow. Three of these are ro-ro vessels in the Wallenius Wilhelmsen fleet and the fourth is the Swift Resolute, which is a 132,000 dwt bulk carrier. On the Wallenius ships the use of emulsion fuel is coupled with the fitting of a scrubber system so that the ships conform with the latest emission requirements.
Currently, Nonox is also equipping one of the Royal Caribbean cruise liners with their system on their six Wartsila diesels that power the diesel electric system. "We have found that the engine manufacturers and the engineers are very receptive to our emulsion system where the water content can be tuned to the particular engine requirements." commented Eric Cottel, the President of Nonox
With the Nonox system the mixing of the fuel and the water is done immediately before the fuel is used in the engine. The company claims that this allows the mix of fuel and water into an emulsion suitable for injection can be achieved without the addition of surfactants that are needed to be added to emulsions when they have to be stored to prevent separation of the fuel and water. The emulsifier unit can be installed in the engine room with minimum disruption and only requires the addition of a power source and a supply of potable water. The mix can contain up to 20% of water with the fuel.
The company claims that there has been a significant reduction in the soot produced by the engines with reductions of between 60-90%. NOx reductions are in the order of 25-50% and the trials have shown that the fuel consumption can be reduced by between 5-15%. So far there have been no adverse effects on the engine wear and tear noted and indeed it is reported that there are reduced soot and carbon problems (which can materialise from slow steaming operations) and turbocharger performance is improved.
This system of creating an emulsion fuel is said to work with both regular diesel fuel and with heavy fuel oil. The captain of the Swift Resolute is quoted as saying that fuel consumption measurements taken before and afterwards have shown a fuel saving of 1.77 tonnes per day. The vessel is fitted with a 15,800hp Mitsui 6180GFCA engine. Nonox produces a range of emulsifiers units that are suitable handling from 25 to 2000 US gallons per hours of fuel.
The Orimulsion technology has been resurrected by Quadrise. Some executives from the original company have set up the new company with the aim of developing the emulsion fuel for use in diesel engines, mainly on ships. A key objective of this development programme is the production of a stable emulsion fuel that can be manufactured from different oil refinery heavy residues, with fuel properties that substantially eliminate the need for any marine engine modifications. The project includes marine engine tests on land and sea, third party verification and approvals, and conclusion of agreements with candidate oil refineries for commercial supply to bunker hubs.
When the Orimulsion technology was used for land-based power generation it was used in both boilers and in diesel engines, notably Wartsila diesels. With this experience and with the blessing of Wartsila, one of the first applications of the Quadrise emulsion fuel will be on a ship fitted with Wartsila diesel.
Quadrise has signed a joint development and royalty agreements with A.P. Moller-Maersk to jointly develop and, on success, commercialise Marine MSAR fuel oil. Maersk is the world’s largest container shipping organisation and one of the largest purchasers of bunker fuel oil. This development programme capitalises on Quadrise’s skills in emulsion fuel applications and in its use in large diesel engines. Maersk will contributes their vast shipping industry experience and provide unsurpassed technical expertise relating to naval architecture, machinery systems, fuels, exhaust gas emissions and ship management. As part of the agreement Maersk vessels will provide excellent testing platforms for these new technologies.
“Quadrise's specialist team are fully engaged on this exciting project which aims to supply marine MSAR as an approved lower cost replacement for bunker fuel oil." said the chairman of Quadrise, Ian Williams. "Bunker fuel oil constitutes approximately one third of the global heavy fuel oil market of 600 million tonnes annually, and is a major operating cost for shipping companies. Marine MSAR has the potential to reduce the impact of rising oil prices on the global freight market and is a key component of the future Quadrise business mix.
"The combination of lower cost Marine MSAR marine fuel and 'on-board' scrubbers offers a potentially compelling compliance solution for the marine fuels market. The Maersk relationship is a strong endorsement of the Quadrise management team, our alliance partner AkzoNobel, and MSAR technology."
Maersk Line has signed an agreement with Spanish energy company Compania Espanola De Petroleos S.A.U. (CEPSA) and Quadrise to test trial Marine MSAR as an alternative marine fuel and it is expected to provide a cheaper and potentially environmentally safer alternative to heavy fuel oil. The trials are due to begin in the first half of 2016, and will see the fuel supplied from the CEPSA Gibraltar-San Roque refinery to Maersk ships. This will follow the installation of an MSAR manufacturing unit at the refinery site. Installation and operation permits are currently being sought for the new unit.
The first Maersk ship to use the fuel will be the Sorø Maersk, a 92,000gt container ship fitted with a 60,000hp MAN B&W two-stroke diesel engine. The trial programme is expected to run until the end of 2016, or early 2017, when engine tests on the fuel will be completed. Subsequently, the sale of the fuel from the refinery would be made following regulatory and commercial approvals.
"We are delighted to have this opportunity to meet the fuel requirements of a leading partner in the marine industry with Maersk using a pioneering technology from Quadrise," said Federico Molina, head of CEPSA's refining unit.
The MSAR oil-in-water emulsion fuel technology reportedly makes heavy hydrocarbon residues easier to use by producing a lower viscosity oil mixed with water. Alternative fuel emulsions, which are water in oil, are produced from heavy fuel oil. By emulsifying refinery residues, as opposed to heavy fuel oil, the refiner is able to create more value, and also a lower priced fuel, by selling the distillates that would traditionally be blended into its heavy fuel oil, according to CEPSA.
So with the development of emulsion fuels there are two distinct technologies emerging. One is where the water is mixed with the existing fuel on a ship to create an emulsion fuel that is used directly from the blender. This is showing benefits in terms of reduced fuel consumption and reduced emissions and is a relatively simple retrofit. The other starts by using refinery residues that might otherwise be unsuitable for use directly as a fuel and which have to have lighter distillates added to make them viable. By using the MSAR technology these residues can be converted into a viable fuel by adding water and surfactants to create a stable fuel that also offers reduced consumption and reduced emissions.
Refineries are obviously in favour of the MSAR system because it offers the prospects of increased profitability and better use of the various grades of distillate from crude oil. This is perhaps a longer term solution to the use of fuel emulsions because it entails establishing refinery bunkering facilities for the fuel whereas systems such as that developed by Nonox are a relatively simple retrofit on the ship. What does seem certain is the fuel emulsions will become a significant part of the future marine bunker market.
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