| With the development of society and economy, the demand of humanities for energy increases year by year while the utilization of traditional fossil fuel is confronted with the environment pollution problems. The circulating fluidized bed(CFB) combustion technology is one kind of low pollution and high efficiency combustion technology which draws people’s attention gradually, and it is widely used currently. Thus, it is imperative to investigate the issue of CFB.Meanwhile, some accidents happened in the process of CFB utilization due to the CFB characteristics and CFB utilization equipment research is not known completely, for instance, the design defect of boiler hydrodynamic, too much ignition fuel is consumed during the start-up process and the air distribution is not uniform. Hence, it is essential to investigate these issues so as to improve the operation efficiency and security based on the characteristics of CFB boiler.The principles and characteristics of CFB boiler were introduced first in this thesis, as well as the development and research situation in China and foreign countries which followed by the purpose and research methods.The major design parameters, design fuel characteristics and the plant layout and operation conditions were illustrated in the second part which were according to the profile of a domestic large-scale 1036 t/h CFB boiler.In addition, the design defect of boiler hydrodynamic was investigated and then the boiler hydrodynamic- corner vortex flow field- circulation ratio strong coupling characteristics were obtained by the vortex flow field simulation, and the water wall pipe hydrodynamic uniformity improvement and optimization methods were put forward in order to improve the security and has great practical significance in large circulating fluidized bed boiler operation. CFB boiler ignition optimization was completed mainly by field test, and the fuel saving technique was found.The boiler fan output ratio optimization was studied finally, the results demonstrated that that when the unit was running in a stable condition, fine-tuning fan output could be considered to achieve better energy saving effect in addition to adjustment of secondary air under different load, the lower panel, which could make the bed temperature is uniform while can also reduce auxiliary power and improve the economic benefits of the unit. |
