Performance And Emissions Modeling Of Natural Gas Dual Fuelling Of Large Diesel Engines

ABSTRACT This paper presents numerical investigations the combustion characteristics and maximum possible natural gas substitution on a large stationary diesel engine dual fuelled with natural gas operation at 600 RPM. The performance effect in the dual fuel diesel engines is investigated using the coupled 1D3D computer simulation of GT-POWER and KIVA-3 computer codes for combustion optimization and emissions reduction. Numerical modeling was performed by varying engine load conditions from 100 to 77 while with increasing the quantity of natural gas substitution from up to 80. The main target of this contribution is to examine the combustion characteristic of a heavy duty 18 cylinder 6 MW electricity generator diesel engine operating in dual fuel mode at various engine loads. Results indicate that up to 80 natural gas substitution is possible over wide range of engine load conditions at higher engine loads. However for 77 engine load conditions depict noticeable engine performance deterioration above 60 natural gas deterioration of particular is higher BSFC and excessive CO emissions. Compared with straight diesel the in-cylinder NOx formation was significantly reduced by as the quantity of natural gas substitution was increased. For example NOx was reduced by 50 while engine at 80 engine load fuelled with 60 natural gas substitution. This is consistent with the reduced peak flame temperature observed in the combustion chamber and that was confined with the fuel spray zone.