| Boiler is one of the main steam power plants. Compared by the other boilers, CFB boiler has its own character and merit. Especially as the advanced clean burning technology, the large CFB boiler has a strong competitive edge in the market. However, the large one also brings some problems that is need to be solved urgently. So it has important theoretical and practical meaning to study on the key problems of the large CFB boiler. This dissertation has done some research on the nozzle structure, nozzle drag character, uneven distributor plate, penetrated depth and track of nozzle jet in the dense phase heat transfer between gas and solid in the furnace, etc.Nozzle is the important burner in the CFB boiler, and its drag coefficient is the base on the nozzle design. The nozzle resistance has impact greatly on the economy and stability of the running CFB boiler. The nozzle resistance relates on the nozzle structure, the nozzle size and the current in the nozzle. The second chapter establishes the nozzle test stand, and study four typical nozzle drag coefficient, the bell type,Γtype, symmetrical arrow type and side arrow type that is developed independently, which compares qualitatively their own advantage and disadvantage. Thus the research helps to choose the nozzle in the engineering design. The side arrow type has been applied in the two CFB boilers (470t/h) reconstruction in the first Baotou power plant, and the results are good.Jet's moving in the dense phase from the nozzle is an important research subject. The forth chapter Based on the momentum theorem, simplified properly, physical models of the nozzle jet on the depth of penetration and the track of the jet in the dense phase have been developed. The depth of penetration of the vertical jet is a Cartan cubic equation, which has analytic solution. The track of jet in the dense phase is a second-order differential equation, simplified properly, which can be numerical solved...
|
PDF Full Text Request