The primary goal of this project is to evaluate a technology called advanced layered technology application (ALTA) as a means to achieve NOx emissions below 0.15 lb/MMBtu in a wall-fired boiler. Reaction Engineering International (REI) is conducting combustion modeling and pilot-scale testing to refine the process design, define the optimum technology parameters, and assess system performance.

The ALTA NOx control technology for wall-fired boilers combines low-NOx burners with deep staging from overfire air, rich reagent injection (RRI), and selective non-catalytic reduction (SNCR). However, the burners are being designed for complete near-burner combustion, rather than traditional staged combustion. The objective of the burner design is to achieve homogeneity of the combustion products in the boiler. Not only does this create ideal conditions for combustion-related NOx control, it also results in a stoichiometry and temperature distribution above the burners that is ideal for the chemistry involved in RRI. REI is conducting computational fluid dynamics (CFD) modeling and pilot-scale testing to optimize the near-burner combustion system and reagent injection. The pilot-scale testing is being conducted on a 5 million Btu/hr coal combustion pilot-scale furnace operated by the University of Utah.

REI will be conducting a second set of CFD modeling studies based on initial pilot-scale combustion results to refine the process design. The final task of the project will involve CFD modeling of a full-scale boiler to evaluate the impact of burner modifications combined with deeper staging and RRI on NOx emissions, unburned carbon, waterwall corrosion, and boiler heat balance.