Research On Flow-through Transformation Of 300MW Unit In Phase ? Of Ezhou Power Plant

The 300 MW thermal power unit is the oldest power generation equipment used in Ezhou Power Plant.There are many problems in the old unit such as high heat consumption and low efficiency of flow-through.With some small thermal power units are shut down by the government,it's particularly important for the 300 MW thermal power unit to increase the electric energy production capacity and the output.As a primary energy consumer,it can not be separated from reducing energy consumption to survive and get development.In order to reduce emissions and save energy,it's meaningful for Ezhou Power Plant to reduce coal consumption and the pollution by transforming the steam turbine.Considering the enterprise,the flow-through transformation of the steam turbines has increased the electric energy production capacity and reduced the cost of electricity.The transformation has obviously economic and social benefits,and it get a good progress in the electric power industry.The following parts are the contents what we studied:1)We analyzed the operation status of the 300MW#1 unit of Ezhou Power Plant,established a mathematical model for optimizing the energy loss of the cascade,and gave an optimization plan for the energy loss of the cascade.A new type of highly efficient post-loading layer flow vane type(SCH)is used at the high pressure cylinder pressure stage.We use a full three-dimensional vane design.In the radial direction of the blade,the pressure forms a “C” shape,and the stage efficiency can be increased by 1%~2%.On the high-pressure cylinder blades,we used a high-load moving blade type(HV blade type),and the stage efficiency was increased by 0.26%.In the high-pressure cylinder adjustment stage,we use the method of meridian contraction of the static cabinet to increase the efficiency of the adjustment stage by 1.7%.In the medium-pressure cylinder,we use high-efficiency post-loading laminar flow vane type and HV leaf type,and the stage efficiency is improved by 0.8%.In the last stage of the moving blade,we used a high-loaded moving-blade line,and the stationary blade was loaded with a laminar flow pattern.In terms of retrofitting,we widened the moving blades at the medium pressure level and replaced the nozzle vanes.The inlet end adopts the meridional contraction type line,and the high pressure partition is changed to the splitter cascade welding.2)We have established a mathematical optimization model for the leakage loss of the shaft seal.The moving blade of the high-pressure cylinder adopts the self-contained crown structure,and the steam-sealed tooth is changed to the urban wall tooth seal.The air leakage is reduced by 25% and the stage efficiency is increased by 0.4%.In the medium pressure cylinder,the tip of the steam seal has increased by 4 to 5 teeth,and the efficiency is increased by 0.15%.We analyzed the 3D CFD data of the steam seal and changed the steam seal to the CCB structure.In the optimization and modification of the shaft seal leakage energy,all the pressure level tip steam seals are designed to adjust the steam seal ring structure,cut off a section of the adjustment stage bucket top cylinder,widen the nozzle group outer ring,in the middle On the bridge steam seal,we increased the number of steam seal teeth and changed the low pressure shaft seal and the partition steam seal to the inclined flat tooth seal.3)We discussed other losses such as throttling loss,exhaust pipe pressure loss,and impact loss.On the moving blades,we used high-frequency quenching and waterproofing to optimize the structure.In the diaphragm structure,we use a sealing button outside the low-pressure three-stage separator to reduce the surface leakage.We optimize the 3D aerodynamic design of the balance hole to improve the efficiency of the stage.In the transformation,we used Stellite alloy on top of the last stage rotor.In the last stage of the moving blade,we use 958 blades,the low-pressure rotor has no central hole forging rotor,and the low-pressure moving blade uses the new college curved and twisted blades.4)By doing the field test and test the efficiency of the steam turbine after the transformation,comparing with the parameters of the steam turbine before the transformation.The results show that the transformation is successful.In this paper,the engineering issues in the production of the plant has been solved by discussing the technology of the flow-through transformation.How to apply the mature technology to solving the engineering issues is what this paper needs to discuss and solve in the professional degree.