Selection of boiler water sampling points
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The boiler drum used in our company does not have a dedicated sampling point; currently, sampling is carried out through the downcomer pipeline. We plan to modify the sampling device. There are basically three opinions regarding sampling online: 1. Take samples from the surface drains of the drum； 2. Take samples from the downcomer line from the drum to the heat exchanger ； 3. Insert the pipe at a level of 50% of the drum water level, which corresponds to 25% liquid level in the drum ； I would like to ask which of these sampling methods is more reasonable, and why? :handshake
I can only say that for all the boilers I’ve seen, water samples are taken from the exhaust ducts, including coal-fired boilers, circulating fluidized bed boilers, and gas boilers
Does the amount of continuous discharge affect water quality or steam quality? The water that enters the heat exchanger enters from the bottom of the steam drum, right? If you want to control corrosion, you should pay attention to that area
Due to evaporation, the TDS value of the boiler water is highest at the surface where evaporation occurs; therefore, the sampling point should be as close as possible to this surface. To avoid the impact of bubbles, it is generally kept about 10 CM below the liquid surface. The boiler sampling point should be at the same location as the boiler’s exhaust stack.
The samples are taken from the top of the steam drum, which affects the quality of the steam. I’m not sure where the heat exchanger you mentioned is installed; could you briefly describe your process? Under normal circumstances, the steam exits the drum as saturated steam; after passing through the superheater, it emerges as superheated steam