Modification of rotary air preheater toward achieving extended life-span utilizing porous media approach: A case study

Abstract

The main goal of this study is to achieve the extended operating life of the rotary regenerative air pre-heater (Ljungström) of Bandar Abbas power plant by modifying operational parameters by decreasing the corrosion. To achieve this goal, a three-dimensional CFD simulation of the Ljungström is carried out, utilizing the thermal non-equilibrium porous media model. Temperatures are validated against measured data from the power plant with a maximum relative error of 5.54% on the Celsius scale, and mass flow rates are validated with a maximum relative error of −5.25%. The effect of the Ljungström key parameters including the rotational speed, cold layer material, inlet air/flue gas temperature, and mass flow rate, are analyzed in presence of leakages and neglecting it, using porous media approach. The leakage effect is investigated considering radial and axial/peripheral clearances. Finally, a simulation is performed by applying feasible improved parameters extracted from the above analyses considering the effect of all parameters together in presence of leakages, which shows a 6.14% improvement in the Ljungström effectiveness, reducing the total leakage to about one-third of the actual model and eliminating any corrosion.

A Novel Numerical Simulation Study of Air Leakage in Rotary Air Preheaters Based on Rotor Thermal Deformation

“…The exploration of the intricate air leakage distribution within the confines of the air preheater proves to be a formidable task, owing to the inherent complexity of its structural design. The manifestation of air leaks in the rotary preheater, induced by discernible pressure differentials, necessitates a nuanced classification into radial, circumferential, and axial domains [4,5]. This intricate phenomenon unfolds at numerous fluid interfaces, notably at the cold and hot ends of the rotor, where their interconnection exhibits a dynamic interplay, resulting in the emergence of a sophisticated flow network.…”

Investigation of safe operating conditions for reducing acid corrosion and ABS deposition in rotary air preheater using computational fluid dynamics

“…They could predict the safe operating temperature of rotary regenerative preheater. Hajebzadeh and Ansari [9] investigated the thermal performance of a rotary regenerative air preheater intending to increase life span by calculating the dew point temperature and modifying the key performance parameters accordingly. However, their work did not focus on the region of air preheater affected by H2SO4 corrosion.…”