Chapter 11 - Effects of fuel reformulation techniques in NOx reduction

Abstract

Energy security and climate change are two major issues faced by governments globally. Reformulations of conventional fossil fuels such as diesel and gasoline using alternative fuels can be an optimal solution for meeting the global energy demand and controlling NOx emissions generated from internal combustion engines. In order to achieve a high-quality fuel that caters to the current legislative norms, additives such as alcohols, ethers, and nanoadditives are used for reformulating conventional fuels blended with alternative biofuels. They play an important role in improving the fuel physicochemical properties and blends, and thereby provide competitive benefits on negating NOx emissions. The formulation aspects of surrogate fuels emulating conventional fossil fuels include the production and refining features of the fuel and their molecular arrangement supported by blend stability after they are homogenized. Furthermore, the concentrations of the additives in the base fuel-biofuel blend play crucial roles in deciding the nature of combustion within the cylinder and the volume of NOx emissions given out while the engine is operating in different operating conditions. From the studies, it is evident that formulating a tertiary combination of a diesel-biodiesel-alcohol blend with carbon nanotubes showed significant reductions of NOx emissions of up to 45% in diesel engines due to the combined effect of the catalytic and oxidative effect of nano metal oxides. Although alcohols are perfect additives in certain concentrations in gasoline engines, their oxygenated nature along with the presence of a substantial quantity of water molecules results in excessive NOx emissions upon combustion.