Why is the small turbine used for backpressure warming, rather than the main air stream?
Thread Content
Why is the small turbine used for backpressure warming, rather than the main air stream?
When the small turbine is in operation, 10 kg of steam is used, while the pressure of the main steam is 35 kg – high-pressure steam at 400 degrees Celsius certainly cannot be used with the small turbine
I remember that the main shaft of the small turbine is in an interference fit with the impeller; the installation and removal temperature is 260 degrees. If high-pressure, high-temperature steam is used, this can cause the fit to loosen, affecting the operation of the equipment. Additionally, high-pressure steam will definitely cause damage to the nozzles and blades. The back pressure at the outlet of the small turbine is only 3 kilograms, unlike in large steam turbines where the steam seals are arranged in stages to gradually reduce pressure. Due to the smaller number of stages and fewer steam seals, the small turbine has a poor pressure reduction effect, which makes it difficult to control its speed and increases the risk of it running out of control. Moreover, the safety valve on the small turbine is not capable of withstanding such conditions
I think the answers are all a bit off-topic. What the original poster is asking is why the main steam isn’t used; it doesn’t refer to high-pressure steam, but rather to the inlet steam during normal operation