Application of the computational method for predicting NOx reduction within large scale coal-fired boiler

• NOx reduction due to injecting swage sludge gasification gas into the combustion chamber.
• Modeling of the reburning process in large industrial pulverized coal boiler.
• Comparison of numerical results against limitations specified by the government regulations.

Constantly increase popularity of the reburning process for reduction of NOx emission, forces to investigate the impact of reburning process on the combustion conditions within the large scale industrial pulverized coal (PC) boiler. For that purpose the constantly developed numerical tools, like the Computational Fluid Dynamic (CFD) can be used. Presented paper shows the usability of the combustion of sewage sludge gasification gas within the retrofitted PC boiler for reduction of the NOx emission. In presented level of model complexity no modifications to the boiler construction for reburning process have been introduced. Evaluated results have been compared with specified limitation and requirements posted to the reburning technology in large scale industrial boilers. Presented paper should be seen as a case study where different location of the syngas injection ports and syngas proportion have been investigated. Moreover, the usability of NOx emission model from commercial CFD code has been presented.