The B&W cyclone is an oddity among the various firing systems used in electric utilities.  Back in the 1950s and 1960s the cyclone was thought to be the final answer for fuel flexibility with minimum conditioning, and B&W was selling a lot of them.  Then NO_X regulations appeared and the cyclone, which fired extremely hot, produced so much NO_X that it seemed to be doomed.  Indeed, not many were built after about 1970 because of the new regulations.  The loss of interest was accompanied by a loss of cyclone experts, as the inventors retired and no one really replaced them.

Today we have found new ways to drastically reduce NO_X produced by the cyclone, with the primary method being overfire air.  Personnel at Exothermic Engineering were among the pioneers at developing and applying overfire air systems to cyclone-fired boilers, beginning in the early 1990s.  Currently we have either designed, tuned or participated in the design of approximately 10 cyclone units overfire air systems.  The latest is installed and operating at Nebraska Public Power District's Sheldon Station Unit No. 2.

In addition to overfire air systems Exothermic Engineering has experience and expertise to correctly tune, control and operate cyclone-fired boilers.  We have tuned or redesigned cyclones with vortex burners and scroll burners as well as the much more common radial burner.  Other projects include LOI reduction, improving slagging, CO reduction and damper automation.  Techniques include both primary and secondary air kinetic energy minimization technique via CFD modeling and tuning, independently controlling primary air pressure and flow for more precise velocity control, adding OFA to reduce cyclone air throughput and re-entry velocity, coal grind correction and blanking plate design.

Exothermic Engineering used Reaction Engineering International (REI) exclusively for all cyclone CFD modeling.