DIESEL TO GAS ENGINE POWER PLANT CONVERSION: A REVIEW AND PRELIMINARY DESIGN FOR AN OPERTING POWER PLANT

The continuous growth in global electricity demand to sustain the ever-growing economy and electrification programs has put pressure on fossil fuels as convenient means of generating electricity. More energy is needed to meet growing industrial energy needs and automotive application in transport with diesel and petrol being the main fuel options. In this study, an operating diesel engine power plant of capacity 119.7 MWe is analysed for potential conversion to a to a natural gas-powered plant with whose main objectives are to reduce total emissions and cost of electricity by substitution of more polluting heavy fuel oil and industrial diesel with cleaner natural gas as fuel. The study showed that the use of natural gas simultaneously reduces the cost of generation per kWh and total emissions. The conversion process involves modification of the fuel injection system to cope with new fuel injection and ignition requirements, newcontrol for fuel injection and reduced air to fuel ratio and lowering of the engines’ compression ratios by increasing the clearance volume for the engine cylinder. The conversion requires provision for natural gas storage facilities and supply system where natural gas can be stored as compressed natural gas(CNG) or liquefies natural gas (LNG). The dual fuel mode proposed a diesel/natural gas ratio of 1:4, which reduced the diesel specific fuel consumption (sfc) for diesel by 81.2% with natural gas consumption rate of 2196.72kg/h leading to annual fuel saving of USD 4.5 million computed at power plant load factor of 0.5.