Design And Theoretical Research Of Absorption Tower Desulfurization Pump For1000MW Thermal Power Unit

This paper is one of the main content of National Science and Technology Support Plan Project named "Key technology research and engineering demonstration application of typical centrifugal pump"(Project number:2011BAF14B00), and the Jiangsu Province Industry Science and Technology Support Plan Project named "Key technology development and application of series large scale flue gas desulfurization absorption tower circulating pump for thermal power plant"(Project number:BE2011141).Thermal power unit absorption tower desulfurization pumps are widely applied in national important industry such as thermal power plant, petroleum refinery, and chemical engineering. Development and application of thermal power unit absorption tower desulfurization pumps have important practical significance and remarkable economic and social benefit to reduce sulfur dioxide emissions from coal-fired power plants and environmental management. Therefore, the research of design method and theory for desulfurization pumps aim that developing its high efficiency structural and hydraulic model. The improving of the unit efficiency and reliability could provide possibility for the pump optimization design from the perspective of the internal flow field analysis. The main research work and creative achievements of this paper are shown as follows.(1) Present research situation of domestic and foreign liquid-solid two-phase flow theory and the liquid-solid two-phase flow pump were generalized from the independent aspects of design theory, experimental study, numerical simulation and comprehensive research. The advanced research progress on the method of blade machinery numerical simulation are briefly introduced, and the development history and growing trend of thermal power unit absorption tower desulphurization pump were analyzed. The Navier-Stokes equation for non compressible viscous fluid used in numerical simulation is analyzed, and the mathematical model required for simulation calculations in this paper is studied and selected.(2) Based on the design theory of liquid-solid two-phase flow pump, design method of thermal power unit absorption tower desulfurization pump was discussed. Two units thermal power unit absorption tower desulfurization pump products with given technical parameters were innovation designed by velocity coefficient method. The design method of blades greatly distorted structure was introduced based on the Bezier Curves, in which way the vibration noise and energy loss were greatly reduced by the twisted blades, and the hydraulic performance of pump was improved as well. The design method of the blades at impeller inlet super long extension was used to improve the pump efficiency and lower operating costs. The back blades arranged on the impeller balanced the axial force effectively. Automatic compensation equipment of impeller clearance and the impeller axial displacement adjusting device is arranged between the desulphurization pump impeller and the pump body, which ensured the efficient operation and the running reliability of the pump.(3) Numerical simulation of type TLB600-700desulfurization pump were separately carried out with clean water as single-phase flow, the medium with a solution containing limestone particles as liquid-solid two phase flow. Calculation results showed that the flow of pump internal flow field is comparative regular and reasonable, which clearly verified the feasibility of hydraulic design, and the characteristics curves of the pump when transport water was forecasted as well. The influence of particle physic-chemical parameters to the pump performance was analyzed under the conveying of liquid solid two phase flow, and the main wear position of impeller and volute were predicted by briefly analysis of desulphurization pump mainly flow components. The three dimensional unsteady numerical simulation of type TLB600-700desulfurization pump inner flow reveals the pressure fluctuation caused by rotor-stator interaction between the rotating impeller and volute.(4) Fluid-solid coupling analysis of impellers in series thermal power unit absorption tower desulphurization pumps were calculated according to ANASYS software. The impeller stress distribution intensive location of the desulphurization pumps, and the impeller maximum deformation position and deformation distribution were obtained. Finally, characteristics of series thermal power unit absorption tower desulfurization pump prototypes were tested, and test results showed that the series desulfurization pump prototypes that designed by innovative design method are reasonable and acceptable. It can be concluded that the design method is reliable and efficient, with a wide range of high efficiency, the pump prototypes efficiency were respectively increased by3.78percentage points and4.15percentage points than national standards.(5) Comparison and analysis between the numerical simulation results and test results showed that numerical simulation could reflect the pump internal flow accurately, which could prove the feasibility of improving thermal power unit absorption tower desulfurization pump efficiency by combine experiment and numerical simulation method. This research provides the possibility of rapid support for development and design theoretical study of series thermal power unit absorption tower desulphurization pump product, which will greatly shorten the design cycle, and simplify the cumbersome process of theoretical calculation.