WORLDWIDE
          R. David Whitby
                                   Marine diesel engine oils
                 Oil requirements in Europe spark concern for the shipping industry.
              TECHNICAL REQUIREMENTS FOR                                                                                                  heavy-fuel oil in the future or that 
              MARINE DIESEL ENGINE OILS in                                                                                                it may not be cost effective for 
              Europe have been changing. The                                                                                              refineries to produce low-sulphur 
              primary drivers are fuel efficien-                                                                                           fuel specifically for the marine 
              cy, fuel type and reduced exhaust                                                                                           industry. Significant refinery up-
              emissions.                                                                                                                  grades would be needed to pro-
                  Most large marine diesel en-                                                                                            duce these fuels and companies 
              gines (both two-stroke and four-                                                                                            may have to charge a premium 
              stroke) are designed to run on                                                                                              for the fuels.
              residual fuel oil, which has a high                                                                                             Another problem is that there 
              sulphur content sometimes up to                                                                                             is little experience of operating 
              5 percent weight. During combus-                                                                                            large two-stroke marine diesel 
              tion, the sulphur is oxidized ulti-                                                                                         engines on distillate fuels for long 
              mately to sulphuric acid. Marine              Marine lubricant marketers differ on how to best formulate                    periods. The optimum TBN and 
              diesel engine oils must therefore             oils for use with low-sulphur fuels.                                          formulation for oils used with low-
              contain alkaline additives to neu-                                                                                          sulphur fuel still needs to be es-
              tralize the corrosive effects of the                                                                                        tablished.
              combustion acids. The amount of these addi-             Exhaust gas scrubbing is permitted by the IMO              Marine diesel engines also can be de-
              tives determines the total base number (TBN)            and the European Union as an alternative to            signed to burn liquefied natural gas (LNG). The 
              of the oil.                                             using low-sulphur fuel. Studies have demon-            long-term supply outlook for LNG is better 
                  Some of the sulphur is emitted from the             strated that scrubbing is economically attrac-         than for crude oil, and the energy-equivalent 
              engine either as sulphur dioxide or sulphur             tive, particularly for ships that operate most-        cost of LNG is generally lower than for heavy-
              trioxide. In 2005 the International Maritime            ly within ECAs.                                        fuel oil. Also there is considerable experience 
              Organization (IMO) imposed limits on emis-                  Switching between low-sulphur and high-            of using natural gas to power medium-speed 
              sions of nitrogen oxides (NOx) and sulphur              sulphur fuels needs little or no system chang-         engines while suitable oils for spark-ignition 
              oxides (SOx) in designated Emission Control             es. But it may require the use of two different        gas engines are available commercially. These 
              Areas (ECAs) under regulations in Annex VI to           engine oils: one with a low TBN from 10 to 20          oils also have low TBNs, but it is not as simple 
              the MARPOL Convention. SOx limits were im-              and another with a high TBN, between 70 and            as reducing the amount of alkaline additives, 
              posed in the Baltic Sea in 2005 and in the              100. The alternative is to use a mid-TBN oil (50       which have detergency properties. Deter-
              North Sea in 2006. (SOx, NOx and particulate            to 60) for both types of fuel.                         gency is necessary to reduce combustion and 
              limits were also imposed for North America in               Marine lubricant marketers differ on how           degradation deposits on pistons and piston 
              2011 and for the Caribbean Sea ECA in 2013.)            to best formulate oils for use with low-sulphur        rings. Supplementary detergent additives are 
                  The current limits for SOx from the start           fuels. Shell, ExxonMobil and Total endorse a           required.
              of 2015 are 0.10 percent for ECAs and for all           single TBN solution, while BP and Chevron                  At present few ships have been fitted with 
              ships at berth in European waters. The IMO              support OEM recommendations and endorse                scrubbers, and not many new ships have been 
              also has a global cap on SOx emissions, cur-            a two-oil approach. Many industry analysts             built with engines designed to run on LNG. 
              rently 3.5 percent, but it is proposed to reduce        believe that two oils are more likely to be re-        This may change as the shipping industry gets 
              this to 0.5 percent starting in 2020, subject to        quired, particularly as 2020 approaches and            closer to 2020.
              a feasibility review to be completed no later           distillate fuels are more widely required.
              than 2018.                                                  The single-oil solution may become at-
                  These limits mean that ships operating in           tractive if more ships are fitted with scrub-                             David Whitby is chief executive  
              the ECAs must either burn low sulphur distil-           bers and fuel suppliers are able to make                                 of Pathmaster Marketing Ltd. in 
              late fuel or fit scrubbing systems to remove             heavy fuel oils with lower sulphur contents.                             Surrey, England. You can contact 
              most of the sulphur from the exhaust gas.               There is some concern that oil refiners may                               him at pathmaster.marketing@
              They can burn higher sulphur fuel elsewhere.            not be able to make sufficient lower-sulphur                              yahoo.co.uk.
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