Numerical Simulation Of Flow Field And Slag Thermal Stress In Keteng Gasifier

Atmospheric gasifier is the best choice for medium or small nitrogenous fertilizer plant with its low capitalized cost maintenance costs.Keteng gasifier is a new efficient atmospheric pulverized coal gasifier with strong swirl flow field,whose primary air and secondary air arrangementmakes a strong swirl flow field in furnace and influences the gasification reaction greatly.Keteng gasifier improves the refractories' life span,coal powder residence timeas well as efficiency of carbon con version.Numerical simulation on flow field of thermal state and slag thermal stress is beneficial to obtain the characteristics and optimize working condition and gasifier structure.In this paper,a geometric model is built for Keteng gasifier flow field,thermal state experiment working condition is simulated using Fluent software.Keteng gasifier thermal state experiment working condition characteristics is analysed.Influence of up and down secondary air ratio and coal flow rate on Keteng gasifier thermal state working condition characteristics is researched.Based on thermal state working condition calculation result,taking temperature field as boundary conditon,slag thermal stress field in Keteng gasifier is calculated by Ansys Mechanical APDL software.For thermal state working condition numerical simulation,the syngas effective gas proportion increases as the up and down secondary air ratio increases initially and decreases afterwards,the working condition up and down secondary air ratio is 2:8 is the best working condition.The syngas effective gas proportion increases as coal flow rate increases,in research range,the working condition coal flow rate is 4.796kg/s is the best working condition.For thermal state working condition numerical simulation,as furnace temperature increasing,thermal stress of slag near burner zone is high while near slag-SiC interface zone is low,the stress type is tension;as furnace temperature decreasing,thermal stress of both new slag and old slag near slag-SiC interface zone is high,while thermal stress of new slag ishigher,the stess type is compresive.When funace temperature decreses,slag layer is more easily to be destroyed.