What is the process of filling a steam drum with water?
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When our unit is in operation, we first bring the pressure in the steam drum to match that of the main system; the pressure is that of saturated steam at 40 kilograms per square centimeter. After that, we activate the water supply process to the steam drum, with a water supply pressure of 60 kilograms per square centimeter and a temperature of around 120°C. I thought that at the moment water enters the steam drum, it would flash off, causing the pressure in the drum to rise sharply. Yet in reality, the water supply results in only a slight decrease in the drum’s pressure. Why is that?
It is recommended that you find a schematic diagram of a steam drum; once you understand its working principle, your problem will no longer be an issue. This is for your reference.
This post was last edited by pzhmotor on 2023-10-17 at 15:30. My understanding is that the higher the pressure, the higher the temperature of the saturated steam. Saturated steam at 120°C has a pressure of 0.097 Mpa. When connected in series with the main pipe, the drum pressure is approximately 4 Mpa, and the temperature of the saturated steam is around 252 degrees℃ ； The temperature of saturated steam at 6 Mpa is approximately 277°C. The feedwater temperature is much lower than the saturated steam temperature; therefore, no flashing occurs in the drum after feedwater is added. (The flash tank is usually under negative pressure.) Water at 120°C inside the drum, once introduced into the steam main, will absorb saturated steam and thereby heat up (until it reaches the saturation temperature); as a result, this will lower the pressure in the main. When synchronizing boilers, generally the outlet of the steam drum is not first paralleled with the steam main. Because during the furnace startup process, the steam pressure and temperature in the drum are unstable, which can cause fluctuations in the main pipe pressure; additionally, this can also lead to a sharp increase in the amount of condensate in the main pipe during the steam supply process. Usually, after the furnace is operating properly and the pressure in the drum is close to that in the main pipe, it is then connected to the main pipe.