Back pressure type steam turbine rapid starting method based on cold end optimization

Abstract

The invention discloses a back pressure type steam turbine rapid starting method based on cold end optimization. The back pressure type steam turbine comprises a negative pressure cold end system, thenegative pressure cold end system comprises a back pressure machine and a cooling water main pipe, one side of an output end of the back pressure machine is connected with a body hydrophobic expansion container, and the other end of the output end of the back pressure machine is connected with a steam condenser. The steam condenser is connected with a condensate pump and a steam-jetting steam extractor, and an outlet of the steam-jetting stream extractor is connected with a condenser. When back pressure type steam turbine is used, the heating speed of a steam cylinder can be increased, the temperature difference between an upper and lower cylinders of the steam turbine is reduced, the risk of dynamic and static collision grinding and large shaft bending is reduced, the steam turbine is safer and more stable, the safety of a power plant is improved, meanwhile, emission of carbon dioxide, sulfur dioxide, nitrogen oxide and the like can be reduced, the steam exhaust and hydrophobic heatof the back pressure machine is recycled, meanwhile, the outward steam supply amount of the power plant is increased, and the economical efficiency of the power plant is improved. The method is suitable for starting processes of various back-pressure steam turbines and is suitable for popularization and use.

Description

technical field [0001] The invention relates to the technical field of steam turbine operation, in particular to a back pressure steam turbine quick start method based on cold end optimization. Background technique [0002] Steam turbine start-up refers to the dynamic process in which the steam turbine rotor accelerates from static to rated speed and gradually rises to rated load. A reasonable start-up method not only needs to ensure the safety and reliability of parts during the heating process, but also requires the best temperature rise rate, which is economical and convenient, and shortens the start-up time. [0003] At present, no matter whether the back pressure steam turbine is started in a hot state or a cold state, it usually starts by exhausting steam into the air. That is, all the steam used is exhausted into the atmosphere before rushing, warming up and speeding up, and connecting to the grid, which wastes energy and at the same time It also produces more than 1...

AI Technical Summary

Problems solved by technology

[0005] Since most of the back pressure machines adopt a single-layer cylinder design without interlayer heating, the positive expansion difference of the unit is large during the start-up stage, which often triggers the expansion difference alarm signal; the main reason is that the pressure difference between the cylinder body and the hydrophobic expander is small, and the hydrophobic The cylinder is not smooth, there is water accumulation in the cylinder, and the phenomenon of "dynamic and static friction" occurs when cranking; the warm-up stage requires an average of one or two "stuck cylinder" processes, which directly lengthens the warm-up time; exhausted, due to the limited amount of steam exhausted by each drain pipe of the cylinder, it still cannot meet the needs of cylinder heating, and the positive differential expansion is still very large, which seriously affects the safety of the unit. Therefore, we have designed a back pressure steam turbine based on cold end optimization. Quick start method to solve the above problems

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