On the atomization and combustion of liquid biofuels in gas turbines: towards the application of biomass-derived pyrolysis oil

摘要

The combustion of liquid biofuels in gas turbines is an efficient way of generating heat and power from biomass. Gas turbines play a major role in the global energy supply and are suitable for a wide range of applications. However, biofuels generally have different properties compared to conventional fossil fuels. This can lead to various problems in case biofuels are directly used in existing installations. This thesis aims to provide better insight into the combustion of biomass-derived pyrolysis oil in gas turbines. Pyrolysis oil is a combustible liquid that can be produced from non-edible biomass via the fast pyrolysis process. Two research objectives have been formulated to support the development of pyrolysis oil combustion technology. The first objective is to describe the evaporation and flame characteristics of pyrolysis oil. This objective has been addressed by developing a CFD model based on the Euler-Lagrange method in ANSYS Fluent. The second objective is to determine the effect of fuel viscosity on the atomization and combustion in a gas turbine. Given that pyrolysis oil is an unstable fuel, reducing viscosity via preheating is only possible up to a limited temperature. Therefore, pyrolysis oil is more viscous than standard gas turbine fuels such as diesel, which can deteriorate the performance of the atomizer. This problem has been studied by measuring the fuel spray characteristics, and relating these to burning tests in a micro gas turbine. The present research provides more fundamental knowledge, mathematical models, experimental setups and practical guidelines that may speed up further developments in combustion technology for pyrolysis oil.