Chapter 5 - A comprehensive perspective on a promising fuel for thermal engines: Syngas and its surrogates

Syngas can be considered a promising fuel leading to a drastic reduction of greenhouse gas emissions in its life cycle. Given the strong demand for energy and the need to resort to energy systems, in general, and to thermal engines, in particular, that are sustainable in terms of polluting emissions, the use of innovative fuels, such as syngas, becomes essential. This work intends to present syngas as one of the possible candidates for advanced thermal engines. Specifically, this work investigates the energy capability of syngas in industrial applications based on the use of internal combustion engines. A brief overview on the production of syngas is given, followed by an analysis of the different applications of this fuel in thermal engines. Dual-fuel compression ignition, homogeneous charge and direct injection spark ignition engines are analyzed from performance and emissions perspectives, following both experimental and numerical approaches. The performance and emissions of these engines are compared with those of engines running on conventional fuels and the main differences are highlighted. One of the main conclusions is that the combustion characteristics of syngas are strongly dependent on its component species, which influence the low density, the laminar flame speed and the wide flammability range.