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Abstract Natural gas is considered nowadays to be one of the most vital sources of energy. It is extracted from different area. Natural gas consists of different gases which differ in percentages depending 011the extraction place, and also differ within the same source from time to another. This obviously results in variation in both the physical and chemical properties; and hence particular considerations should be taken when using natural gas as a fuel in internal combustion engines. The aim of this work is to study the effect of using the associated natural gas as a fuel .on a natural gas engine specified and adjusted with another natural gas fuel by the engine manufacturer. The experimental work was performed on a stationary gas engine generator set .on an off shore platform for crude oil collection in the Gulf of sue~. It has a brake power of 450 kW at 1200 rpm and compression ratio of 7: 1. Appropriate adj ustrnents of the engine fuel y tern, and the ignition timing \ ere implemented to accommodate for the difference in gas characteristics. The main differences between the two gases are the calorific value and the Octane number. The engine was loaded by different loads (1/4, 112, 3/4, and full load). The measurements include the values of the brake power and the percentages of the dry volume fractions of CO and O2 in the exhaust during each run. Hence, the air/fuel ratio was calculated. Also, the differential pressure between the gas and air at the mixer entry was monitored.The results show that the brake power was the same as the rated power specified by the manufacturer. This was gained due to the adjustments done to air/fuel ratio and the ignition timing according to the gas characteristics. Also the engine performance was compared to the engine performance data given by the manufacturer. Also, this thesis includes a survey of some relevant literatures in the use of natural gas in both petrol and diesel engine. It also covers the technical aspects related to the conver ion of both engines types to use natural gas instead. Key words: Gas engines, Natural gas as an engine fuel, Spark ignited reciprocating gas engine, Gas composition. |