Quick cooling system capable of protecting inner cylinder and outer cylinder of turbine

Abstract

The invention discloses a rapid cooling system beneficial to protecting the inner and outer cylinders of a steam turbine, comprising an air inlet connected with parallel automatic main steam valves A and B, automatic main steam valve A and automatic main The steam valve is used to control the steam intake of the steam turbine, and can quickly close and cut off the steam intake in an emergency. The other ends of the automatic main steam valve A and the automatic main steam valve B are connected with steam trap one, high pressure cylinder and exhaust port one in turn. and check valve 1; the air inlet is also connected with steam trap 2 and the medium pressure cylinder in turn. Cylinder and vacuum breaker valve, the vacuum breaker valve is a safety valve. The invention has large heat transfer temperature difference, large steam intake, relatively uniform cooling of rotors and cylinders, and multiple air intake passages connected to the air intake port, that is, more air intake areas, which are convenient for monitoring and controlling the cooling rate.

Description

technical field [0001] The invention relates to a cooling system, in particular to a rapid cooling system beneficial to protecting the inner and outer cylinders of a steam turbine. Background technique [0002] A steam turbine is an external combustion rotary machine that converts steam heat energy into mechanical work. After the steam from the boiler enters the steam turbine, it passes through a series of ring-shaped nozzles and moving blades in sequence to convert the thermal energy of the steam into the mechanical energy of the rotation of the steam turbine rotor. In the steam turbine, the energy of steam is converted in different ways, thus constituting the steam turbine with different working principles. There are many types of steam turbines, and there are many classification methods according to the structure, working principle, thermal performance, application, and number of cylinders. According to the structure, it can be divided into single-stage steam turbine an...

AI Technical Summary

Problems solved by technology

[0003] Modern high-parameter and large-capacity steam turbine inner cylinders and outer cylinders have insulation layers with good thermal insulation performance, which is very effective in strengthening the thermal insulation of steam turbine inner cylinders and outer cylinders to reduce heat loss. However, during the natural cooling process after maintenance shutdown, due to The heat dissipation conditions of the inner and outer cylinders of the steam turbine are poor, the heat storage is large, and the wall temperature of the inner and outer cylinders of the steam turbine drops slowly, which requires a long cooling time. With the development of electric power technology and the improvement of automation level, most of the large-scale units in China Equipped with a powerful decentralized control system (DCS) and digital electro-hydraulic control system (DEH), and the operating conditions are very good, and can be evenly adjusted under the given value of DEH (that is, load, steam temperature, steam pressure) Steam temperature, steam pressure and unit output. Therefore, many power plants now use sliding parameter shutdown to reduce the temperature level of the inner and outer cylinders of the steam turbine before major repairs, so that the temperature of the inner and outer cylinders of the steam turbine can be reduced to a minimum, so as to start maintenance in time , to shorten the maintenance period. However, in the process of shutting down with sliding parameters, if the interlayer cooling steam source between the inner and outer cylinders of the steam turbine is not properly selected, the desired effect will not be achieved. In severe cases, the metal walls of the inner and outer cylinders of the steam turbine will be heated. Cracks caused by impact. Now the sliding parameter shutdown has been widely used in large-capacity steam turbine units. Due to the large capacity, high parameters, and large size of the unit, and the widespread use of high-quality insulation materials such as calcium silicate and aluminum silicate, the unit has brought After shutting down, the natural cooling speed slows down, which prolongs the maintenance and opening time of the unit and other problems

In addition to the normal major and minor repairs of the unit that need to be shut down for cooling, as there are many defects in the quality of the unit itself, there are also many random inspections. Every time it is shut down, it is allowed to cool naturally, which will inevitably greatly affect the availability of the unit. It also affects the normal performance of the superiority of the large unit, so it is necessary to perform forced cooling on the airflow pole

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