Simulation research on combustion and pollutants of a methanol-fired boiler

Abstract

With the development of low-carbon energy systems, clean fuel combustion has become an important research direction for industrial heating and boiler systems. Methanol is considered a promising alternative fuel because of its convenient storage, wide sources and relatively clean combustion characteristics. In this thesis, the combustion and pollutant formation characteristics of a methanol-fired boiler are studied by numerical simulation. Methanol is directly introduced into the combustion chamber in vapour form and mixed with air for combustion. A three-dimensional furnace model was established, and ANSYS Fluent was used to analyse the temperature distribution, NO formation and CO formation under different operating conditions.

The results show that the excess air coefficient and inlet air temperature have significant effects on the combustion process and pollutant emissions. Increasing the excess air coefficient reduces the outlet temperature and slightly decreases the CO mass fraction, but it increases the NO mass fraction because of increased oxygen availability. Increasing the inlet air temperature raises the outlet temperature and promotes NO formation, while the CO mass fraction does not show a clear monotonic trend. Overall, suitable air supply and inlet air temperature are important for balancing combustion stability, wall heat transfer, thermal efficiency and pollutant control. This study provides a reference for the operation optimization and emission control of methanol-fired boiler systems.