The function of the waste heat boiler recirculation pipe
Thread Content
This question should ideally be posted in the boiler technology discussion forum, but it falls outside my area of responsibility. I believe our refining department will also be able to provide the correct answer, as many people there have experience operating boilers as well.
In boilers with a capacity of over 20 tons, there is a line that connects the outlet of the feedwater mixer and the inlet of the economizer to the bottom of the boiler’s steam drum or to the downcomer. This is what we call a circulation pipe. Its main function is to protect the economizer during the start-up and shutdown of the boiler: when the flow rate through the economizer is low but the flue gas temperature is high, this can shorten the lifespan of the economizer or even cause damage to it. This circulation line is used to enable water circulation within the steam drum in order to protect the economizer; it is usually closed off, in my opinion