Emission control of nitrogen oxides in the oxy-fuel process

The interest in oxy-combustion as a method to capture carbon dioxide has increased drastically during recent years. The oxy-fuel process offers new process conditions and may take advantage of innovative techniques as well as of new ways to apply conventional measures for emission control. The present work reviews available techniques for controlling both the emission of nitrogen oxides (NOx) to the atmosphere and the content of NOx in the captured carbon dioxide. The results indicate that for a first generation of oxy-fuel power plants, conventional primary NOx control should be sufficient to meet today's emission regulations, if based on emission per unit of fuel supplied. However, there are several opportunities for new methods of NOx control in oxy-fuel plants, depending on future emission and storage legislation for carbon capture schemes. Improved understanding of the behaviour of nitric oxide and nitrogen dioxide during compression and condensation of carbon dioxide is needed, as well as improved knowledge on the influence of the parameters of oxy-combustion on nitrogen chemistry.