Numerical Simulation And Experimental Study On The Fluidization And Abrasion In A CFB Boiler

The circulating fluidized bed (CFB) which was developed as an efficient and low-pollution combustion technology in the recent decades, has achieved a rapid commercial development at home and abroad. However, due to the complexity of the gas-solid two-phase flow in the furnace of CFB boiler, so far, whether in the academic theory or in the projects, the study of this flow model is still not perfect. At the same time, abrasion, as one of the most important factors that restricts the advantage of CFB boiler, is also a problem that needed to solve badly. So studying on the problems above plays an important role on the design and operating of a CFB boiler.Through a combinative method of numerical simulation and experiment, the paper has studied the flow dynamic characteristics of two different furnaces, a traditional type and an improved type. The paper has also studied the porosity distribution, the velocity distribution of the air and solids, the pressure distribution and the bed resistance characteristics in the furnace, the analysis showed that the improved furnace structure made a better performance in the porosity distribution and the solids velocity distribution, especially in the radial direction, it can increase the uniformity of the flow in the furnace, which can make a better combustion and a more uniform bed temperature distribution, and can also avoid leakage of residue, coking and other undesirable consequences.According to the study of flow dynamic characteristics in the furnace, the paper brought up a new structure of anti-abrasion, and studied the different impact on the gas-solid two-phase fluidized state and the relative abrasion of two different furnaces. The results show that the different structures of the furnace have a great influence on the gas-solid two-phase flow in the furnace. According to the cubic speed equation measuring the relative abrasion, we can clearly see the improvement of the new anti-abrasion structure. The simulation results can provide theoretical reference for the design and operation of large-scale CFB boiler.