Designing a New Bell-Type Primary Air Nozzle for a Large-Scale Circulating Fluidized Bed Boilers

Mustafa Metin Çam, Hakan Serhad Soyhan, Mansour Al Qubeissi, Cenk Çelik

Research output: Contribution to journalArticlepeer-review


The design of energy efficient engineering systems is crucial for sustainable operation when economic and environmental consequences are considered. Circulating Fluidized Bed (CFB) boilers, which are among the major contributors to world electricity production, are still increasing in numbers and unit sizes. Primary air nozzles are key components of CFB boilers that may decrease energy consumption and increase energy efficiency, and they need to be carefully designed. There are certain types of nozzles commonly used in the air distribution grate, but even minor design improvements on the nozzle can significantly decrease the pressure loss. This work is about optimizing the bell-type primary air nozzle used in the Turkish lignite-fired ÇAN Thermal Power Plant (CTPP), which has two 160 MWe CFB boilers, through computational fluid dynamics (CFD). Initially, the bell-type nozzle was designed newly by changing the inner head holes geometry. After that, the nozzle geometry was optimized by changing the orifice size and angle to decrease the pressure drop, increase the orifice velocity outlet, and flow uniformity through CFD simulations. With the optimum nozzle geometry, the velocity at the outlet orifices was increased, and a decrease of 2.86 kPa was achieved in the total pressure loss. Furthermore, when the nozzle orifices were designed downwardly with an angle of 105°, pressure drop across the nozzle decreased by 7.6%, and the uniformity index increased by 2 % at the outlet orifices. Using the bell-type primary air nozzle, which is newly designed, in the CTPP boiler not only will save 2.26 GWh/year of energy consumption but also minimize the backflow risk in the boiler operation.
Original languageEnglish
Article number127065
Number of pages14
Early online date9 Dec 2022
Publication statusPublished - 1 Mar 2023


  • Nozzle
  • CFD (computational fluid dynamics)
  • Fluidized bed combustion
  • Power Plant
  • Optimisation
  • Parametric analysis

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Mechanical Engineering


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