Low NOx firing systems

We are making pulverized coal-fired boilers environmentally friendly by aplying best available practices to desing a powdered fuel low NO_x firing systems.

Since 1995, MORE, s.r.o. has carried out research on power generation boilers and applies its vast experience in improving the environmental friendliness and reduction of NO_x emissions as it carries out proposals of primary measures to reduce NO_x. It uses the CAE method and BAT for modifications of current boilers and supplies or offers retrofits and completely new projects.

Solution for reducing NOx emissions

We are focusing on the following areas during design process:

• Combustion system solution
• Detailed burner design
• Designs or modification of burners for low-emission combustion
• Application of the combustion system with respect to the shape and size of the combustion chamber and necessity to increase the range of regulation performance of the boiler so that it has high combustion stability
• Design of air zoning for an optimal combustion process layout
• Usage of recirculated flue gas to optimize combustion temperatures
• Ensuring a suitable temperature to enable usage of the SNCR method in the case that it is necessary to further lower NOx emission levels
• Preparation of pulverized coal in beater wheel mill circuits
• Securing good-quality grinding fineness of pulverized coal and optimization of classifier function
• Improving the mill’s performance during the change of fuel while maintaining grinding quality
• Regulation of relevant mode parameters of the pulverized coal mixture with respect to the performance of the entire mill
• Usage of recirculated flue gas to dry the fuel
• Transport and distribution of the pulverized coal mixture into burners
• Securing a regulated distribution of the pulverized coal mixture into burners and burner sections
• Regulation of the primary mixture flow rate and coal concentration after height levels according to boiler performance
• Operation of the combustion process and beater wheel mill circuits
• Design of modifications and completion of system measurement and regulation for boiler air mode operations and preparation of fuel
• Algorithms of combustion system regulation, including air zoning and flue gas recirculation
• Algorithms of beater wheel mill circuit regulation
• Optimization of the combustion process and beater wheel mill circuits
• Optimization of the combustion process with respect to minimization of NOx emissions, decreasing the frequency of operational problems, getting the necessary superheated steam and achieving a good performance of the boiler
• Optimization of the performance and grinding fineness of beater wheel mill circuits

 From proposal to final solution

The basic proposal of primary measures was carried out using our own SW and know-how and tested by CFD (via SW Ansys Fluent), enriched by our own proprietary approach enabling specific kinetics of pulverized coal combustion in a CFD model.

The basic concept that is tested is further optimized to achieve the necessary quality for further steps of the project. In addition to proving the concept of low NO_x firing system , and associated technology modifications by the CFD model, we also focus upon:

• Fuel circulation in the beater wheel mill
• Separation of pulverized coal in the classifier
• Flow in the pulverized coal pipeline and distribution of the pulverized coal mixture into burners
• Pulverized coal flame, pulverized coal flow and combustion in the furnace with air zoning and recirculated flue gas
• Using our knowledge in the kinetics of pulverized coal combustion, or measuring kinetics of new fuels in a drop tube at the Energy Research Centre, Technical University in Ostrava
• Possible testing of the fuel zoning proposal, air and inert for a specific type of fuel, and testing of the overall approach in the experimental combustion facility.