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Application of a pre-combustion chamber (PCC) ignition system is one of the methods to improve combustion stability and reduce toxic compounds emission, especially NO x . Using PCC allows the operation of the engine at lean combustion conditions or the utilization of low calorific gaseous fuels such as syngas or biogas. The paper presents the results of an experimental study of the combustion process in two stroke, large bore, stationary gas engine GMVH 12 equipped with two spark plugs (2-SP) and a PCC ignition system. The experimental research has been performed during the normal operation of the engine in an industrial compression station. It was observed that application of PCC provides less cycle-to-cycle combustion variation (more than 10%) and nitric oxide and carbon monoxide emissions decreased to 60% and 26% respectively. The total hydrocarbon (THC) emission rate is 25% higher for the engine equipped with PCC, which results in roughly two percent engine efficiency decrease. Another important criterion of engine retrofitting was the PCC location in the engine head. The experimental results show that improvement of engine operating parameters was recorded only for a configuration with one port offset by 45 • from the axis of the main chamber. The study of the ignition delay angle and equivalence ratio in PCC did not demonstrate explicit influence on engine performance.

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This paper presents the combustion process of gaseous fuels in turbine combustion chamber. Authors investigated fuels with significant amount of inert gases like nitrogen and carbon dioxide. For selected fuels, experimental studies in an experimental silo combustion chamber were performed. During the experiment the effect of molar fraction of nitrogen and excess air ratio on the temperature and gas composition inside and in the outlet channel of the combustion chamber were analyzed. At the same time the numerical calculation were performed with using Cantera and Ansys FLUENT software. Basic parameters like adiabatic flame temperature and laminar flame speed and process of the flow with combustion in simplified geometrical model of combustion chamber were calculated. Results from CFD calculation were compared qualitatively with the experimental result. The CFD part was supplemented with a calculation with carbon dioxide used as inert gas. Research on utilization of fuels like biogases, nitrogen-rich natural gases and their mixtures is very important, especially in countries where energy production is based on coal and lignite. The use of these kind of fuels in high-performance combined cycle allow to significantly reduce emission of toxic compound into the atmosphere.