Regeneration system optimization for particles captured in a granular bed-cyclone coupled separator

CHANG Ming; FAN Yiping; LU Chunxi

doi:10.13732/j.issn.1008-5548.2026.02.014

Abstract：Objective Efficient removal of solid particulate matter from exhaust gases is crucial for ensuring clean production processes in the energy industry.This study investigates a granular bed-cyclone coupled separator system,which enhances separation perfor-mance by integrating centrifugal separation with granular bed filtration.The built-in granular bed effectively captures and filters fine particles(＜5 μm),which are difficult to remove using centrifugal force alone.However,these particles tend to clog over time.To ensure long-term stable operation,the granular bed must be regenerated rapidly and effectively to remove the trapped particles.Currently,spouted bed regeneration technology is employed,but issues such as captured particle attrition and second-ary pollution from regenerated gas still exist,hindering its industrial application.To address this,riser-spouted bed regenera-tion technology is adopted to stabilize the pressure drop in the coupled separation system.Nevertheless,this method can still cause secondary emissions of fine particles,resulting in additional environmental concerns. Methods This paper analyzed the effects of optimization techniques,such as a newly designed screening regenerator and tail gas recirculation,on the performance of a granular bed-cyclone coupled separator system.Large-scale cold-model experiments were conducted to investigate the impact of inlet gas flow rate and dust concentration on separation performance under various exhaust gas recirculation ratios.The research focused on key performance parameters,including pressure drop,overall collection effi-ciency,outlet particle size distribution,and grade efficiency.A vibrating regenerator was designed and evaluated based on the coupled separation device.Its separation characteristics,including regeneration efficiency and pressure drop performance,in the micro-airflow vibrating regenerator were examined through experiments and compared with those of the conventional spouted regeneration methods.Additionally,the effects of screening regeneration on the overall performance of the coupled separator were further explored. Results and Discussion The introduction of regenerated exhaust gas significantly enhanced the separation efficiency of the coupled separator,with collection efficiency exceeding 99.2％across all operating conditions.The median particle diameter of dust in the outlet gas stream decreased from 1.67 μm to 0.82～1.04 μm,and the grade efficiency for dust particles smaller than 3 μm was notably improved.At an inlet dust concentration of 14.99 g/m3 and an exhaust gas recirculation ratio of 25％,the coupled separator achieved relatively high collection efficiency.Additionally,fine particles in the recirculated exhaust gas were primarily distributed within the 0.323～1.047 μm range,playing a crucial role in filter cake formation.Among the separated particles,92％of dust particles larger than 10 μm were captured by the cyclone shell,while the particle size distribution cap-tured by the granular bed varied with the recirculation ratio,primarily ranging from 0.409 to 10.954 μm.The optimal operating conditions for the micro-airflow vibrating regenerator were as follows:Ws=0.69 kg/s,ui=0-0.035 m/s,ρin=7.5～22.5 kg/m3.The experimental results showed that the maximum operating pressure drop of the vibrating regenerator was 80 Pa,much lower than that of the riser-spouted regenerator under similar circulation volume(3 kPa).Moreover,the efficiency of the vibrating regen-erator remained stable at 85％to 95％.Additionally,due to the low gas velocity of the vibrating regenerator,no significant frag-mentation of the captured particles occurred during the separation process.Based on the dust particles collection behaviour in the novel regenerator,two key mechanisms were identified:entrainment and screening.In the free-settling space,gas-solid phase countercurrent contact separation was achieved through the entrainment mechanism,while the screening mechanism func-tioned via interception on the sieve surface.When the regenerative gas velocity was below 0.02 m/s,the screen separation mechanism dominated.Larger dust particles fell into the dust collection tank due to inertial and gravitational forces,contribut-ing 50％～80％to regeneration efficiency.When the regenerative gas velocity exceeded 0.02 m/s,the gas flow entrainment effect intensified,and the contribution rate from this mechanism could reach up to 70.8％.Under the micro-airflow vibrating regenera-tion mode,the separation efficiency of the coupled separator ranged from 89.9％to 99.6％,and the pressure drop remained rela-tively stable and nearly unaffected by the changes in regeneration gas velocity.The centrifugal separation performed effectively for dust particles larger than 10 μm,with a separation contribution rate of approximately 90％.The built-in granular bed effec-tively trapped dust particles within a range of 0.32～10.95 μm. Conclusion The optimization of the regeneration system,achieved through precise control of key regeneration mechanisms and structural improvements,significantly enhances the particulate matter capture efficiency of the coupled separator.This optimiza-tion enables effective interception and separation of particles across varying sizes while maintaining stable processing efficiency under complex operating conditions.It thus provides solid technical support and practical validation for advancing the technol-ogy from laboratory research to industrial application,establishing a strong foundation for subsequent large-scale engineering implementation.