Research On Through-flow Reconstruction And Performance Test Of The300MW Steam Cylinder

Energy conservation and consumption reduction is the main objective for the facilityreconstruction of the coal-fired power plants. In the earlier stage, the steam turbine inservice had a poor performance in heat rate and through-flow efficiency and its maincomponents exposed many potential security risks after being in service for a long time. Itshould positively adopt the advanced and mature technology to upgrade the steam cylinder,hardly dig up the internal potential, perfect the working security, economical efficiency,minimize the contamination to the environment and further adjust to the peak regulation ofthe power grid with the purpose of adapting to the new situation, ensuring the steamcylinder advanced technology, improving the operation efficiency, reducing the energyconsumption and bettering the economical returns.This thesis illustrates the theoretical basis of through-flow reconstruction, thetechnical regulations before reconstruction, main structure and current operation situationand confirm the main factor of influencing the efficiency–low efficiency of thethrough-flow of steam cylinder by further studying the test regulation of the heatingperformance, calculation methods, etc.,conductingpre-reconstruction tests,comprehensively analyzing testing data of the unit performance, efficiency value of everycylinder and the testing data of underload operation.After making a comparison of the economical returns and security between twotransformation schemes, it‘s decided to carry out a comprehensive reconstruction schemeon the high, medium and low through-flow. Reconstructing the through-flow of certain300MW steam cylinder in service by using the present mature technology can improve theworking efficiency, increase the service life and the power output and better the operationreliability and economical efficiency.The main technologies and measures taken in this through-flow reconstruction are:1) reconstructing the countercurrent of the high-pressure cylinder to concurrent andincreasing grades of the high and medium through-flow;2) using the brandonsteam seal for balancing piston of high, medium pressure; 3) forming a entire high-pressure internal cylinder composed of high-pressurebalancing piston, internal cylinder and high voltage static ring;4) using the bend torsion joint forming blade.After finishing the reconstruction of the through-flow, we evaluate the economicalreturns of the reconstruction by analyzing the main thermal performance‘s index and pointout the shortcomings appearing during the reconstruction and also provide lessons for thethrough-flow reconstruction of the similar units.