ROFA^® Technology—Nalco Mobotec’s Approach to Reducing Harmful Pollutants

Rotating Opposed Fired Air (ROFA-CFB) is Nalco Mobotec’s state-of-the-art, patented system for staging the CFB furnace, reducing NO_x and SO_x, and optimizing combustion.

ROTAMIX^® Technology is Nalco Mobotec’s patented, advanced Selective Non-Catalytic Reduction (SNCR) solution. In this process, the bulk flow upward through the furnace is set in rotation, using custom-designed, asymmetrically-placed air nozzles. This action brings about increased turbulent mixing and bulk rotation throughout the entire furnace—improving gas temperature and species distribution, heat absorption, CO oxidation, and particle burnout in the upper furnace.

ROFA-CFB mixing and rotation technology prevent bulk laminar flow and raise efficiency substantially, allowing more effective use of the entire furnace volume for the combustion and sorbent mixing processes. The ROFA-CFB technology swirl reduces maximum reaction temperature, reduces CFB emissions, burns out carbon more efficiently, and increases convective heat absorption. These improvements in combination can boost overall boiler efficiency significantly.

By mixing combustion air more effectively, the ROFA system also reduces the need for surplus air. Less unused combustion air means that less cooling takes place in the furnace—further raising the efficiency of heat absorption. The ROFA system has been proven to enhance CFB limestone utilization and SNCR chemical utilization, resulting in lower SO_x and NO_x.

Strategically placed along the furnace walls, ROFA boxes optimize reduction of SO_x and NO_x while raising combustion intensity. Ultimately, the performance and functionality of the entire ROFA system works in conjunction with, and is dependent on overall furnace geometry and operation. Operators realize significant savings by improving limestone utilization and SNCR performance while achieving the targeted reductions in CFB emissions.