REI doesn’t just solve NOx problems; we work with our clients to optimize furnace performance in many different industrial applications. Our state-of-the-art models give us the ability to manage LOI, corrosion and slagging.


Combustion modifications for NOx control in coal-fired boilers can increase the unburned carbon (UBC) in the ash, as measured by an increase in loss-on-ignition (LOI) in the ash. Increases in LOI reduce combustion efficiency and can have negative impact on electrostatic precipitator (ESP) performance and sale of the fly ash.

REI’s 3D, multi-phase, reacting CFD codes have been combined with an advanced model of char burnout accounting for the effects of thermal annealing and coal heterogeneity. As a result, REI’s models are used to predict unburned carbon levels in fly ash, as a result of the effects of coal type and operating conditions.


Utilities with low-NOx firing systems would like to quantify the increased potential for waterwall wastage when evaluating strategies involving combustion modifications. A decision-making tool is needed to quantify the effect of these modifications on wastage rates.

REI performed computational simulations on several utility boilers (tangential, wall-fired and cyclone) with the goal of understanding and addressing corrosion difficulties related to combustion difficulties related to combustion modifications for the reduction of NOx emissions. Units evaluated include both subcritical and supercritical units.

REI has coupled corrosion monitoring technology with CFD analysis to develop a Corrosion Management System that can effectively monitor and anticipate corrosion behavior in combustion systems.


Deposition of ash in coal-fired boilers reduces heat transfer and may increase NOx emissions and/or corrosion. Excessive slagging can be expensive for utilities in terms of outages (planned and unplanned) and boiler de-rating.

REI couples 3D multi-phase CFD models of full-scale boilers with sophisticated models for ash deposition and deposit heat transfer. The result is a unique capability to predict deposit initiation and growth in a coal-fired boiler.