Design and Analysis of Air Distributors and Bed Materials of Fluidized Bed Boiler

Abstract

This research deals with the design and analysis of the nozzle and bed materials required for fluidized bed boiler. The design parameters (Diameter of the bed particle, Range of the terminal velocities, Minimum Fluidization /Bubbling velocities, Maximum amplitude and steady velocities) were calculated using Microsoft Excel by interpreting and solving various formulas. Best bed material was selected on the basis of their various characteristics like porosity, adhesive or cohesive properties, resistance to flow etc. An important characteristic change of air distributor velocity with combustion chamber temperature has been established. ANSYS was used as a simulation tool for the analysis. Static Structural solver was used to carry out the strength analysis of the designed wind box. Likewise, computational fluid dynamics (CFD) was carried out using FLUENT solver. Air flow inside the wind box and fluidization phenomena was verified using FLUENT. Furthermore, the designed system was checked for its validity by comparing the results from the Excel sheets and theoretical calculations with simulation results. Lastly, correlation between temperature and velocity inside combustion temperature were determined to identify their relationship with each other.

Designing a new bell-type primary air nozzle for large-scale circulating fluidized bed boilers

“…CFB boiler's air grate main purpose is to distribute the primary air uniformly in the combustion chamber [8]. Therefore, its design has great importance in terms of combustion efficiency in the CFB boilers [9]. Due to the defects of distributor grate design, many problems may be occurring in the boiler operation.…”