LPG as auxiliary fuel for GenSets

摘要

The L16/24 GenSet is adapted to utilise different types of LPG. The target was to develop a dual fuel medium speed engine, which is able to utilise LPG with minimum influence on the thermodynamic internal processes in the engine. However all aspects of safety matters are carefully considered during the design of the gas system including gas piping in the engine compartment and they fulfil all requirements from the involved classification society. The development of the gas system is based on experience from spark ignited gas engines produced by MAN B&W Diesel, four-stroke. The main idea during development was simplicity to enhance both safety and transparency of gas handling, and engines processes. Advanced PLC equipment monitors engine parameters and controls the correct conditioning of the gas supply to ensure proper engine operation at all conditions. The PLC equipment is coordinated and integrated in the existing diesel engine control and survey system. The primary measure to obtain simplicity is keeping the fluid fuel, MDO or HFO, as main fuel. This ensures that both load and the combustion process are controlled by the injection of liquid fuel. The test of the developed system has included start and stop, shifting to and from gas mode, load steps, efficiency evaluation, emissions as well as thorough verification of the gas supply unit function and all the safety equipment. The tests are conducted applying both marine gasoil and heavy fuel oil as liquid fuel. In total seven different LPG types were performance tested and released for operation in field. The gas types, which have been tested, are butane as the heaviest and ethylene as the lightest. After the laboratory tests are finished, the first commercial installations are brought into service and the paper will address also the first field experience.