Reciprocating Engines for Future Fuels and Emission Demands
Oil is still the dominating fuel for marine applications and will continue to be so for a considerable time. However, alternative fuels like gas, Orimulsion, and maybe wood based oil will start to take market share. Deciding for the direction of development is the relative strength of the main drivers, which are economy and environmental issues. Probably there will be increasing emphasis on environmental considerations. This paper describes how the reciprocating engines can cope with the demands of the future.
Key Words: Future Fuels, Emission Demands, Smokeless Engines
1. THE FUEL SCENARIO
For many decades oil has been the dominating fuel for marine applications. That situation is certainly going to continue for many decades to come. However, alternative fuels are going to take market share at a pace determined by the strength of the drivers. The strongest drivers known at the moment are the relative price of energy products and environmental consciousness. Other possible drivers could be change in trade patterns, break-through innovations concerning processes, or significant disturbances to world peace. Figure 1 shows a marine fuel scenario for which the author's company prepares the products.
Natural gas is a strong fuel candidate in a scenario dominated by environmental consciousness, as there is no sulphur in natural gas, the particle level is insignificant, and the carbon dioxide emissions are reduced due to the balance between carbon and hydrogen.
Wood-based oil would be the only fuel in the scenario which is truly renewable. The problem with wood-based oilis that it does not really exist. Small amounts are produced via a pyrolysis process, and engine tests have been made to confirm that it is a fuel useful for a diesel engine. It is certainly possible to think that a more sophisticated process would emerge which could turn wood and other waste into a consistency very similar to today's oil. Production of wood-based oil in significant quantities will demand farming of huge energy forests. For shipping wood-based oil is certainly an interesting alternative of utilizing solar energy for transportation.
Hydrogen is today pretty much in focus, because it is the fuel needed for fuel cells. Today hydrogen is extracted from natural gas or gasoline. Such a loop is of course not solving any of the world's future energy supply questions. If and when hydrogen becomes a popular fuel, it will need to be produced by solar power. In a way it is appealing to think that this is the future energy solution, because there will be no end to the supply. Whether the reciprocating engine will survive into the hydrogen era or not, is a question of the relative development speed of hydrogen production processes, the fuel cell technology and the efficiency of engine based systems. Whatever the future is in the very long run, the reciprocating engine has a reasonably long future, in fact much longer than the history up to now.