Combustion is a complex chemical process, and there is no such thing as “complete” combustion. In a typical furnace, poor and inefficient combustion results from uneven flow and temperature distribution across the furnace and higher levels of unburned carbon. This uneven flow of gases creates “hot spots” in the furnace and results in poor distribution of the oxygen needed to complete combustion.

The Nalco MobotecSystem™ was Developed to Improve Combustion Control and Optimization

Increasing the turbulence in the boiler produces better mixing in the system providing more contact of the reactants for combustion. This increased turbulence is achieved by introducing very high velocity air into the upper part of the boiler, thus enhancing the three T’s of combustion: Time, Temperature, and Turbulence. This process breaks up the laminated flow and results in a consistent combustion temperature and allow for combustion optimization. The principle is the same concept of stirring a cup of coffee to dissolve the sugar evenly.

Comparison of a Traditional Combustion System with the MobotecSystem™

The graphic above on the left shows a traditional combustion system plotted for time versus temperature. As temperature and retention time increase, so does the formation of NO_x. Lower temperature and retention time result in poor combustion increasing CO and unburned carbon levels, while reducing the formation of NO_x. Traditional low-NO_x burners operate in this area. Good combustion is confined to the center of the time temperature curve.

The bell-shaped curves of the traditional combustion system graphic indicate distribution of retention time and temperature, showing only a small part of the curve in the good combustion zone.

The graphic above on the right shows the time versus temperature plot following installation of the Nalco MobotecSystem, with the bell-shaped curves more centered in the area of good combustion. NO_x formation has decreased, while CO and unburned carbon have been stabilized or reduced.

The Nalco MobotecSystem Offers Cost-Effective Combustion Optimization Solutions

Increasing the efficiency of the combustion process provides several positive, profitable effects: fuel consumption decreases, total efficiency increases, and harmful environmental emissions decline. Reduced fuel consumption is a direct cost saving, and reduced emissions help preserve our natural environment. A typical Nalco MobotecSystem installed to improve combustion control pays for itself within a very short period of time.

Baseline vs. ROFA^® SYSTEM Burnout

Compares unburned carbon before and after the ROFA^® System is in place in a tangentially fired (T-fired) boiler. In both cases, the actual unburned carbon is very low. However, it is easy to see the typical fireball associated with a T-fired boiler before the ROFA System and the superior mixing that occurs after the installation of the ROFA System. It also shows more unburned carbon is captured as bottom ash prior to ROFA installation.

Comparison of CO levels before and after the ROFA system in T-Fired AND wall-fired boilers

The level of CO emissions in the flue gas leaving the boiler is a good indicator of complete combustion. The lower the CO levels, the more efficient the combustion process. Compare CO levels in T-fired and wall-fired boilers before and after ROFA System installation. The fireball associated with a T-fired boiler can be seen before ROFA System installation and afterwards, with the fireball broken up and CO level reduced.