In March this year, The U.S. Environmental Protection Agency proposal to designate waters off the North American coasts as an Emission Control Area was adopted by IMO, the International Maritime Organization. The North American ECA is a key part of a comprehensive EPA program to address harmful emissions from large ships. Which are the time schedules of upcoming emission regulations? How are marine engine manufacturers preparing for the tighter air emission limits being adopted? Henrik Segercrantz explores.
The North American 200 nautical mile Emission Control Area for sulphur oxides (SOx), nitrogen oxides (NOx) and particulate matter (PM) will also include Canada's Pacific and Atlantic coasts, the South coast of Alaska, and Hawaii.
The latest component of EPA’s coordinated strategy for addressing emissions from ocean-going vessels is a proposal, from August this year, to designate an Emission Control Area for the U.S. Caribbean. The United States submitted a proposal to IMO in advance of the September 2010 IMO meeting, requesting that waters around the coasts of Puerto Rico and the U.S. Virgin Islands be designated as an ECA.
Other EPA programs to address harmful emissions in the U.S. include voluntary partnerships under EPA’s Clean Ports USA program and implementation of a Clean Air Act rulemaking that EPA finalized last December.
The first designated ECA areas, governed by IMOs revised Annex VI (Regulations for the Prevention of Air Pollution from Ships) of the International Convention for the Prevention of Pollution from Ships (MARPOL convention), were those of the Baltic Sea and the North Sea area, which also includes the English Channel. The revised Annex VI allows for ECAs to be designated for SOx and particulate matter, or NOx, or all three types of emissions from ships. The regulations implementing the new North American ECA are expected to enter into force in August 2011, with the ECA becoming effective from August 2012.
In the U.S. Caribbean ECA proposal, ships operating in the area would be required to use lower sulfur fuel beginning as early as 2014, and new engines would have to meet emission standards requiring the use of advanced emission control technologies, beginning in 2016.
In coming years many new ECAs are expected to be set up along coastal areas worldwide.
In parallel with reductions in sulphur oxide emissions, taking place in coastal ECA areas and, on a less demanding and time lagging level globally, also nitrogen oxide (NOx) emissions from ships are being cut both globally, through upcoming Tier II, and within designated ECA areas, in which areas the very tough Tier III limit is being implemented.
These new and more stringent regulations to reduce harmful emissions from ships are expected to have a significant beneficial impact on the atmospheric environment and on human health particularly for people living in port cities and coastal communities.
Sulfur oxide and particulate matter
Catching up with the time schedules for the ECAs in Europe, and locally in California (see below), tougher EPA sulfur standards in North America are to phase in starting on August 1st, 2012, when sulfur content for ship fuels is limited to 1.00 percent, or 10,000 parts per million, and reaching a cap of 0.10 percent, or 1,000ppm, on January 1st 2015. As an alternative to switching to cleaner distillate marine fuels, shipowners have the alternative to install an exhaust gas cleaner, or scrubber, allowing heavy fuel oil to be used as fuel. Enforcing the stringent ECA standards on sulfur content in fuel will slash particulate matter emissions by 85 percent, according to EPA.
From July 1st this year, the sulfur content in fuels for the ECAs of the Baltic Sea and the North Sea including the English Channel, provided an approved scrubber is not in use, was limited to 1.00 percent (or 10,000ppm), from previous 1.5 percent (15.000ppm). As of year 2015, the limit is to be 0.1 percent (1,000ppm). Outside ECA areas the current global sulfur cap is still 4.5 percent, to be reduced to 3.5 percent from January 1st 2012. Ships sailing under the flag of a country that has not implemented Marpol Annex VI can, even then, continue to use less environmentally friendly fuels within ECA areas, as long as they do not call an ECA port. From year 2025 this is though to change when a limit of 0.5 percent is to enter into force globally. There is a checkpoint in 2018. If suitable fuels are available the starting year would be 2020.
In Californian waters Marine gas oil (DMA) with a maximum sulfur content of 1.5 percent or Marine diesel oil (DMB) with a maximum sulfur content of 0.5 percent has been in force since July 1st 2009, for ocean going ships within 24 nautical miles from the coastline. From year 2012 oceangoing vessels calling on California ports must switch to Marine gas oil (DMA) or Marine diesel oil (DMB) with or below 0.1% sulfur, within 24 nautical miles of the California coastline for the main and auxiliary diesel engines as well as auxiliary boilers.
Also in other areas low sulphur emissions is being promoted. The Port Authority of New York and New Jersey’s Ocean-Going Vessel Low-Sulfur Fuel Program reimburse vessel operators half of the costs for using low sulphur fuels within 20 nautical miles of the port on a first come first serve basis due to an annual budget cap. From the beginning of year 2010, ships in European Union ports have to run their engines on 0.1 percent sulfur fuels.
Nitrogen oxide emissions
Nitrogen oxide NOx emissions from ships are to be further cut from that of current IMO Tier I level, which entered into force for new ships from year 2000. The Tier II level of IMOs revised Marpol 73/78 Annex VI will enter into force globally from next year, for ships with keel laying on or after January 1st 2011. Tier II will reduce nitrogen oxides in the exhaust gas by 15.5 percent to 21.8 percent, depending on engine speed. From year 2016 Tier III enters into force in all ECA areas, including that also in North America. Nitrogen oxides are cut by as much as 80 percent from the current Tier I level, down to between 3.4g/kWh to 2g/kWh, depending on the engine speed.
EPA's final emission standards under the Clean Air Act for new Category 3 marine diesel engines with per-cylinder displacement at or above 30 liters installed on U.S.-flagged vessels were published on April 30, 2010. The final engine standards are equivalent to those adopted in the amendments to Marpol Annex VI Tier II and Tier III standards. EPA adopted changes to the diesel fuel program to allow for the production and sale of diesel fuel with up to 1,000 ppm sulfur for use in Category 3 marine vessels.
For the latest Emission Control Area (ECA) initiative for the U.S. Caribbean, EPA estimates that the total costs of improving ship emissions from current performance to ECA standards while operating in the proposed ECA will be approximately $70 million in 2020. The costs to reduce a ton of NOx, SOx and PM are estimated at $500, $1,000 and $10,000, respectively. EPA states in its announcement of the proposal: "The economic impacts of complying with the program on ships engaged in international trade are expected to be modest. For example, the impact on the price of a cruise on a medium-sized cruise ship that operates a route between the U.S. mainland and Puerto Rico is estimated to increase by approximately US$0.60 per passenger per day for a 5-day cruise. This represents a less than one percent increase in the price of such a cruise. Container ships operating in the proposed ECA are expected to see a cost increase of less than one percent of the cost of transport of a 20-foot container, or about $0.33 to $1.35 per unit, depending on the size of the ship and the length of the route."
Greenhouse gases, GHGs
Meanwhile, IMO is also addressing the reduction of greenhouse gases (GHGs) from ships.
Carbon dioxide CO2 greenhouse gas emissions are directly related to ships fuel efficiency and fuel consumption of the engines, and is thus relates directly to engine builders' R&D work for fuel efficiency and to total transport efficiency of ships, a topic gaining much attention by the shipbuilders.
According to IMO, good progress is being made on related technical and operational measures, with further work being undertaken on market-based measures. This work is to continue at the next session of IMO’s Marine Environment Protection Committee (MEPC 61), which will meet from 27 September to 1 October 2010.
At the MEPC 60 meeting in March, opposition was though evident on several matters. Several countries, including China and India, insist on requiring a differentiation between developed and developing nations regarding this issue and the need to comply with the principles of the UNFCCC (called the CBDR principle). To steer clear of this principle, a proposal was presented to regulate energy efficiency only, without specifically setting limits on CO2 or greenhouse gases. A working group was set up to continue the work on a plan for implementing a mandatory energy efficiency design index EEDI for ships, despite opposition. The COP15 meeting in Denmark last December left no guidelines on greenhouse gases to IMO.
Engines bound for cleaner emissions
Marine engine manufacturers are working hard to develop and test technologies through which the demanding new emission levels can be met efficiently. Maritime Reporter talked to the two largest, MAN Diesel & Turbo SE, on their two-stroke low speed engine developments, and with Wärtsilä Corporation, on their developments on the four-stroke medium speed engine side.
Low speed engine developments
Mr. Lars Bryndum at MAN Diesel & Turbo SE is Director of Customer Supports, Marine Low Speed, Sales & Promotion. He has a long career within MAN, having worked at the company since 1979 in management positions for R&D, on vibrations, and later design of large bore engines. Bryndum holds degrees in Mechanical Engineering and Naval Architecture.
When asked about how MAN is approaching upcoming air emission regulations for their low speed engines, he goes directly to the point: "We have prepared for Tier II by means of internal adjustments of the engine. There is higher scavenging air pressure, another timing of the fuel injection, introduction of rate shaping in the fuel injection profile, and exhaust valve timing," he tells Maritime Reporter. "With all these things we are ready to meet Tier II but it has cost some increase in fuel oil consumption." He points out though that the increase is not that big on the engines where the fuel injection is electronically controlled. "We are all the time getting new information from testing the engines. We have 53 different models of stroke-bore ratio, rpm, loadings etc. so we are still learning things. We call it the Tier II evolution." MAN is currently actively testing its engines to adjust the parameters further to cut fuel consumption but to still meet the emission levels required. "We do not come back to Tier I level but we will cut back somewhat," Bryndum points out.
How is your development going on for Tier III, entering into force in 2016?
"For Tier III we have to reduce the NOx by 80 percent from the Tier I level. Only in ECA areas you need this drastic reduction. Outside ECA areas Tier II will apply." Bryndum notes that this will require shifting between modes of the engine or requiring engine adjustments. "NOx formation is a combustion feature resulting from high temperature and high pressure, where the nitrogen and the oxygen in the air react and create NOx, which is NO or NO2. In order to reduce this chemical process you need to lower the temperature." Bryndum mentions that there are several methods to do this. MAN has not tested spraying water directly in the combustion chamber, as some other engine builders, but has instead mixed water into the fuel, which then evaporates during the burning process resulting in a cooling of the gases. Bryndum points out that with this technology, called WIF, an 80 percent NOx reduction could not be reached. MAN has also tested another method, scavening air moistening, called SAM for two stroke engines (and HAM for four stroke) where water is sprayed into the hot air after the compressor on the turbocharger. Bryndum describes the process: You can spray in salt water which will immediately evaporate and cool down the scavening air. You then take out some droplets from that and spay in fresh water once more. Then you wash out any salt droplets after which a third spraying with fresh water takes place. The air goes through the cooler without any salt content and when the intake air enters the cylinder the temperature will be around 70-80 deg.C.. and completely humid, saturated with water vapor. This results in relatively less atmospheric air which reduces the amount of oxygen. Combined with the higher specific heat capacity of the water vapor and less oxygen with a lower partial pressure, the formation of NOx is lower. "That was one technology we tested some years back. We could reach a 60-70 percent NOx reduction but an 80 percent reduction seemed to be out of range, so we looked for a third technology." The technology Bryndum refers to is EGR, exhaust gas re-circulation. The principle is the same as with SAM, to use another gas which has less oxygen than the atmosphere in the combustion process. The engine's re-circulated exhaust gas has an oxygen level which is reduced. It is first cleaned from soot and for sulfur dioxide, components in engines burning heavy fuel oil. After this it passes through a cooler and to the scavenging air receiver. "The reduced oxygen level, from 21 percent, which is in the atmosphere, down to maybe 16 percent in the intake air, gives a tremendous lowering of the combustion temperature and therefore also in the formation of NOx." MAN has made lots of tests with EGR on their research engine proving that this technology works. With a recirculation of about 40 percent of the exhaust gas an 80 percent reduction of the NOx is reached. The cleaning process from soot and sulfur dioxide, needed to avoid corrosion of the engine air cooler, is done using a scrubber, developed and patented by MAN. The water in the scrubber will over time become acid and is neutralized with sodium hydroxide, or caustic soda, transforming into harmless natrium sulfide or natrium hydrosulfide, which can be discharged into the sea. A filter in the water loop takes out the soot. "I should add that with the EGR the fuel penalty, when you reduce NOx by 80 percent, is small, less than one percent." The pressure of the exhaust gas is approximately 0.3 bar lower than the scavenging air pressure. When the exhaust gas is cleaned in the scrubber, its pressure has to be increased using a blower. The additional power consumption of the blower is some one percent of the total power of the engine."
"You have to switch on this EGR, when you go into an ECA area. There will be more and more ECAs in the world," Bryndum reflects. "If the Mediterranean Sea becomes an ECA area it will have a huge impact on how many ships that has to have Tier III reduction technology onboard."
In order to comply with Tier III, required for ships with a keel laying after January 1st, 2016, MAN applies a strict development schedule both using test engines and in testing in real operating conditions. One EGR is currently in service test, since last May, on container vessel Alexander Maersk, on its MAN 7S50MC low speed engine. MAN is looking for experiences with the scrubber design and with the water cleaning system, and the impact of the re-circulated exhaust gas on the engine, cylinder and air cooler. "This is a long term test where you will see the results after one year. We have made the first inspection and it looks nice, but we need more," he points out. As this is a retrofit design, MAN is now also working on a final EGR design, integrated and optimized for its various engine types. Also these need to be tested before year 2016.
MAN is currently proposing to shipowners to become test partners in testing the first integrated EGR engine. "We want an owner who is interested and where we can access the vessel. We can not have one sailing in the South Pacific all the time. We need someone coming to Europe or Singapore frequently, allowing us to get onboard and examine the engine. The long term service experience we can only get from tests onboard a commercial vessel."
"After 2016 maybe 1,000 shipsr will have their keel laying, every year. How many of these ships, maybe 50 percent, will have to have the possibility to meet Tier III, Bryndum asks. "You can see there is a risk that you will go from a few prototypes to something like 500 engines with EGR every year. If there is something we have to modify later on, while in service, we can become very busy if the design is not well proven," Bryndum reflects. "There is one strange thing with this as you can imagine that many shipowners will order their ships just before 2016, as these only have to fulfill Tier II. They can go with Tier II into all ECA areas without any EGR or a catalytic converter. There could be an advantage to order ships with keel laying before 2016, resulting in a halt or in a reduction of orders of new vessels after that. Economically, the vessels which are not operating with Tier III equipment will be more efficient. Tier III equipment will cost more due to extra fuel and energy consumption." But MAN has an attractive card up its sleeve. With the EGR running with a tested 21 percent recirculation, one fulfills the Tier II requirements regarding NOx emissions, but also with a reduction in fuel consumption compared to Tier I. He shows a graph showing -2.6 percent excluding the power loss of the EGR blower. "This is a result of our internal engine development for fuel savings," Bryndum notes. "This means that when you have installed your EGR and you sail in a Tier II area, you can still used the EGR and be more efficient than with a ship without an EGR. This is what we hope will be the bait for the shipowners to go into a test with a final execution of this EGR system."
Bryndum points out that MAN walks two paths regarding technologies for reducing NOx, the other one being catalytic converters, a proven technology that works well, with a handful of vessels operating such already. "There you take the exhaust gas before the turbocharger. That means at a high temperature, at a high pressure, and then you put it into a Selective Catalytic Reactor, SCR, and then through the turbocharger. "We go for these two solutions equally, because we know there are those who would prefer one of the technologies." For MAN there is no hesitation in this matter. "These are the two only options," Bryndum stresses. "We have to work very hard and invest a lot of efforts and money to have reliable and proven technology ready in 2016." Bryndum notes further that the SCR will need ammonia, or urea, to operate and wonders will that be available in the upcoming ECAs around the world? He notes, on the other hand, that the EGR requires caustic soda, or sodium hydroxide. "But this is more available worldwide, we guess." "We now go full steam for both solutions. We have to drive the market and to give clear guidance now what to go for."
Will the development on the turbocharger side, for example in two-stage turbocharging, affect low speed engines regarding NOx emissions?
Two-stage turbocharging development takes place for our four-stroke engines, in connection with Tier III complience" Bryndum notes. "However the on-off operation of the EGR system in ECA and non-ECA calls for flexible turbocharger performance, and there our VTA Variable Turbine Area technology will be very useful. In the long run the higher scavenging air pressure available with two-stage turbocharging might be beneficial also on two-stroke engines but that is a next step in the evolution.
How does the decreasing on sulfur dioxide in fuels influence on your low speed engines?
"You can say that up to 1950 the low speed engines were running on low sulfur fuels, as they were running on diesel oil, and they were running very well. It took us fifty years to refine the design so that they could run on these heavy fuels with high sulfur and all kinds of bad things in the fuel. Now the pendulum is not swinging back, but we have to run on both, the very clean gas oil or diesel oils and the dirty heavy fuel, and this is a challenge," Bryndum notes. "But this has been done already for some years, on the U.S. West Coast, where there have been strict voluntary rules on sulfur emissions. The big container and other ships have been switching to marine gas oil in California voluntarily." Bryndum points out that if one is running a low speed engine on low sulfur fuel for a prolonged time, say for more than a week, one should change the cylinder lube oil. The cylinder lube oil has an detergent agent which neutralizes the sulfur. If there is no sulfur to neutralize then this agent which contains calcium, and if supplird in too big quantities, starts to build up deposits on the piston top and in the piston ring grooves etc. Another issue Bryndum points out is that the low sulfur fuels have nature low viscosity. "We have a limit for the fuel regarding viscosity, two centistoke at 40 degrees. There are some marine gas oils and also maybe diesels which can be delivered down to 1.4 centistroke at 40 degrees. We are now introducing a cooler just before the engine inlet that assures that we will have sufficient viscosity. That is simply because a higher viscosity gives a better oil film, and less risk of seizure of the parts." A suitable high viscosity is also needed by the fuel supply pumps of the ship. A third issue is with old, somewhat worn fuel pumps, where, according to Bryndum, the fuel might be too thin to allow building up the injection pressure due to leakages, with a risk of not being able to start the engine. "These are the three big issues on running on low sulfur marine gas oil or diesel oils."
Any comments on the discussion on heavy fuel oils fouling the Selective Catalytic Reactor?
"With SCR we take the exhaust gas before the turbocharger. That means it has sufficient temperature to go into the catalytic reactor without clogging, even with high sulfur contents. In addition we are also able to match that with the engine. We can at least with the electronic engines adjust the timing in order to increase the temperature of the exhaust gas at lower engine loads. Thus we are able to operate our engines together with the catalytic reactor and high sulfur fuels also at low load," Bryndum notes. "But you should think at one thing. When you aim at Tier III and need to lower the NOx by the catalytic reactor you are not allowed at the same time to use high sulfur fuels. Therefore that helps for the sulfur clogging of the catalytic reactor."
Developments with medium speed engines
Maritime Reporter talked with Mr. Mikael Troberg, Director, Testing and Performance, R&D, at Wärtsilä Corporation, who has worked at the company since year 1993. He started his carer at Wärtsilä's diesel engine plant in Turku and then worked at the Vasa Engine Laboratory for four year. For the last eleven years, he has been located in Trieste, in charge of the Testing and Performance activates within Wärtsilä covering both two-stroke and four-stroke diesel and gas engines. "We have twenty-one test engines in our engine laboratories two of which are located in Finland, and one in Italy, Switzerland and in Spain. The performance development is related to the output, emissions and efficiency of our products," Troberg notes.
Tier II enters into force quite soon. How are your engines prepared to cope with these rules?
"Our engines are Tier II compliant. We have further developed the Tier II performance package for all our engines which we are implementing. These have an improved performance regarding fuel consumption. Normally when you want to decrease NOx emissions fuel consumption increases. We have done some developments to optimize the engine for Tier II, and are to improve the fuel consumption near to that of Tier I, although we have Tier II." Troberg points out that with the latest development “package” the Tier II engines of Wärtsilä will remain competitive "as they are". "We are not going to do much upgrading on these. We focus instead very much on Tier III. This is a big step. Most of our product development aims at having competitive engines that fulfill the Tier III requirements."
Wärtsilä looks at three different technologies for Tier III, Troberg describes. First there is the technology called "after treatment", which is a completely standard Selective Catalytic Reactor, SCR. "Anyone can buy a standard SCR and place it after the engine. The problem with SCR is that if it is not delivered together with the engine one does not receive a fully optimized package. We can optimize the engine if we also supply the SCR." Secondly Wärtsilä is looking into the engine technology. "This is perhaps the area where the main focus is within our engine R&D." The third technology promoted by the company is to use engines driven by natural gas, which produce very low emissions. Troberg notes that there is further development taking place also on these engines. "These are the three main technologies we believe in."
"The most demanding work is naturally on the engine technology side, where we have the goal to work between both Tier II and Tier III. The engines operate sometimes in a Tier II area and sometimes in a Tier III area. A quite intelligent engine is needed to get it to function well, both on the fuel injection side and regarding the valve mechanism. This double requirement comes from the fact that Tier III applies only in ECA areas, and some ships operate in ECA areas only occasionally. The shipowner wants an engine optimized for Tier III when operating in a Tier III area and for Tier II when operating in a Tier II area, as there is a definite difference in the engine efficiency. Probably some day in the future all coastal areas will be governed by the Tier III regulation," Troberg estimates.
Troberg presents various NOx reduction technologies under development by the company, and their current ability to reduce NOx emissions. The list comprises High Pressure 2-stage turbo charging reducing NOx by some 40 percent, Low NOx combustion tuning achieving a reduction of about 10 percent, an EGR Exhaust Gas Recirculation system achieving a 60 percent reduction in NOx, Charge air humidification -40 percent, Water fuel emulsion -25 percent, Direct water injection -50 percent and an SCR system achieving a NOx reduction in the exhaust gases of some 80 percent. By using a Wärtsilä Gas engine with fuel conversion, i.e. using a dual fuel engine, a NOx reduction of some -85% can be achieved. Currently only Gas engine technologies and an SCR system fulfil Tier III. Wärtsilä is currently develping also the following technologies to meet Tier III, alone, or in combination: two-stage turbocharging, Exhaust Gas Recirculation, Water Fuel Emulsion, and Direct Water Injection. "Operational flexibility between different emission areas will be a success factor for the future engine concepts," Troberg states.
When looking at the other engine technologies, apart from the SCR and gas engines, there is the High Pressure two-stage turbocharging where the changed combustion results in reduced NOx gas emissions by some 40%. "Through this we have reached halfway of the Tier III requirements. In addition to this we need something else," Troberg describes. Wärtsilä is looking at various alternatives here, an SCR on the engine, an EGR system where exhaust, or as a third solution, various ways of humidification, where DWI, Direct Water Injection, is one possibility, or to inject water behind the compressor. A third method is Emulsified fuel, where water is mixed into the fuel itself. "When the water in the cylinder evaporates, it consumes energy, resulting in a lower combustion temperature," Troberg describes. "The challenge with these methods has been to combine them with high sulfur fuels of more than 3.5 percent, which might results in corrosion. Now in ECA areas where sulfur content will be low these methods can be used without problems, and also in the future when there will be a one percent global cap on sulfur content in fuels, these technologies will become very competitive," he points out. "There is a benefit with water. It is always nearby. We use quite high quality water today, but we work on technologies where sea water could be used directly. That would be ideal."
"As a basis for Tier III we have the two-stage turbocharging, SCR, EGR, and the water technologies. These should all be such that they can be turned off without losing anything in engine efficiency. It should become better when turned off. These technologies should not impair on engine efficiency."
Of these technologies, are there any preferred technical solutions you would opt for today?
"Not actually," Troberg answers. "For the client lifetime cost is what is interesting, and it is very unclear yet what these technologies will cost and which will have the lowest operating costs. Two-stage turbocharging gives a benefit both for NOx and in fuel consumption. That is why we see it as very attractive. It remains to be seen which other technology, applied on this base technology, is the most competitive." Wärtsilä has entered into a cooperation agreement with ABB Turbo Systems and Swiss company specialized in aftertreatment, Hug Engineering, in order to develop a technology comprising two-stage turbocharging and SCR. "We build in the SCR on the engine itself. When the client buys an engine, it is Tier III compliant without the need for any additional outside equipment. If this technology proves cost efficient we will introduce it on the market." Troberg points out that this is a development Wärtsilä believes in much. "First we achieve low emissions. Then the SCR becomes smaller and also the amount of urea needed, as it only needs to reduce about half the amount of NOx. Also the higher pressure reduces the needed size of the SCR. This makes it possible to place it on the engine itself. We are going to build a prototype Tier III compliant engine. When looking at the various environmental requirements being planned or implemented today, the Tier III requirement is the most demanding as such, and is the focus area for the engine builders today," Troberg notes.
CO2 greenhouse gas emissions are directly related to fuel consumption, and thus relates directly to the R&D for fuel efficiency for the engine manufacturers. Troberg points out that their goal is to develop an IMO Tier III minus 80 percent NOx compliant engine without a penalty in fuel consumption. "This is our goal. Things become much simpler if one allows for higher fuel consumption, and higher CO2 emissions, but we believe that there will also be CO2 trading in the future, so this is just a thing where we have to be good."
How do you look at the requirements of the lube oil with various sulfur content fuels?
"Our engines operate with fuels with any sulfur levels. We have no problems with running our engines on low sulfur fuels. The only thing is that our minimum viscosity requirements have to be fulfilled, which is a minimum 1.8 centistoke. The reason is simply that otherwise leakage occurs in the fuel injection pump and the performance is affected. Problems can also arise if the maintenance interval recommendations are not followed. Normally when you run on heavy fuel oil you use lube oil with a high TBN number to help neutralize combustion gases. If you run on low sulfur fuel, you do not need a high TBN content in the lube oil. This is a question of the cost of lube oil. It does not have a practical implication on the engine itself. If the operator knows he will be running on low sulfur fuel for an extended time he can use cheaper low TBN lube oils to save in costs. On the medium speed engine side the problems with calcium build-up on the piston etc., as experienced with low speed engines, has not been found."
Your comments on Selective Catalytic Reactors getting clogged when using heavy fuel oil?
"Yes this is true. We have some challenges. There are development projects ongoing for developing an SCR without fuel grade limitations. Until now there has not been a big demand for an SCR with high sulphur content heavy fuel oil, as the ECA areas are introducing the sulphur cap. The market is looking for a solution with heavy fuel oil also for the ECA areas. This would mean that an exhaust gas scrubber in combination with an SCR would be preferred for the ECA areas," Troberg notes. "It is not the sulphur as such that causes problems, but mainly the ash and the vanadine in the fuel. Within our own company Ecotec, we sell and develop SCR. We strongly believe that the winner in this game will be the one that can handle both low sulfur fuels and high sulfur fuels. A scrubber behind the engine is something that will most probably be attractive. A scrubber capable of running on bad heavy fuel oils will most probably be very competitive in the future. The price of good quality fuels will rise and the difference in price between good quality fuels and heavy fuels will increase from what it is today. The cost efficiency of a combination of a scrubber operating on heavy fuel will improve from what it is today. We do not always deliver the SCR though. There are projects where a client buys our engine and an SCR from somewhere else."