Study On The Improvement Scheme Of The Flow Passage Of Taidian 600MW Steam Turbine

Energy conservation and environmental protection are the two most important directions for China’s energy development.For coal-fired power plants,on the one hand,they respond to national policies,on the other hand,they can improve their own economic effects,enhance their competitiveness,and pass on existing steam turbine units.Flow transformation is one of the most effective measures at present.To this end,for the Taipower 600MW unit to optimize the flow-through part of the structure and transformation,select the optimal solution for the actual transformation,and verify the performance of the unit after the transformation of the program,the optimization program is as follows:(1)The high-pressure cylinder adopts the high-pressure vane ring-holding integrated design scheme,including the high-pressure vane adopting the curved and twisted new blade type,and the high-pressure rotor replacing the end shaft seal to optimize 10 transformations.(2)The medium-pressure cylinder transformation plan includes 9-stage optimization of medium-pressure vane baffle with new blade design replacement,medium-pressure vane with curved and twisted new blade type,and end shaft seal optimization.(3)The low-pressure cylinder retrofit solution consists of 11 optimized retrofits.The fifth and sixth stage tips are made of honeycomb-sealed final blades with 915mm blades.After testing,the system performance after optimization is as follows:Under the working condition of THA,the efficiency of the high pressure cylinder of the steam turbine is 88.44%,which is 0.46%higher than the design value,which is about 0.27%higher than the guaranteed value,and the efficiency is 3.20%higher than that of the modified front cylinder.In the test,the cylinder efficiency was 93.53%,which was 0.6%higher than the design value,0.92%higher than the guaranteed value,and 3.05%higher than before the transformation.The average low-pressure cylinder efficiency(UEEP)after correction of the low-pressure cylinder exhaust volume flow rate is 90.28%,which is 0.70%higher than the design value and 1.07%higher than the guaranteed value.Under the full opening condition of the valve,the efficiency of the high pressure cylinder is 90.04%,and the efficiency of the medium pressure cylinder is 93.48%.After the first and second types of correction,the heat consumption rate is 7852.1kJ/(kW·h),which is 17.9kJ lower than the design value./(kW·h),the economy is 0.23%higher.The flow capacity of the unit under the four-valve full-open(4VWO)condition reaches a design value of 630 MW.It can be seen that after the flow reform,the high and medium cylinder efficiency under the THA condition reaches the guaranteed value and the design value,and the low pressure efficiency reaches the design value.The four-valve full-opening condition has improved the flow capacity of the unit,and the transformation is successful with good results.