Effect of hydrogen content on engine using biogas-hydrogen in hybrid renewal energy system

Abstract

Hydrogen has special properties such as extended combustion limit, high combustion rate, large diffusion coefficient, high adiabatic temperature, so when added to biogas, it helps to improve efficiency and reduce pollutant emissions. However, when the hydrogen content is high, NO_x emissions increase due to the increase in combustion temperature. The level of NO_x emissions is closely related to the maximum pressure in the cylinder, the higher the peak pressure, the greater the NO_x emission level. When the engine is working with f=1, with a hydrogen content of 10-20%, the economic, technical and emission levels of the engine are improved. However, when the hydrogen content in the mixture increases beyond 20%, NO_x emissions increase sharply while the indicated engine cycle work of the engine increases insignificantly with the hydrogen content. Hydrogen content in the mixture with biogas about 20% is optimal both in terms of thermal efficiency and pollutant emission level.