Boiler feedwater temperature issue
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Our company currently has a boiler with a capacity of 4 tons per hour. The contract specifies that the feedwater temperature should be 20 degrees. I would like to use the company’s preheating system to heat the feedwater; I estimate that the temperature after preheating will be around 100 degrees. I was wondering if this is possible. I would appreciate any advice from those with more experience
What is the pressure of the boiler? Is a economizer included?
It is very important to determine whether a economizer is present, as per the question from a friend from Qin Yu. In general, the water supplied to small steam boilers is not sent directly into the boiler drum; instead, it is first heated through an economizer before entering. It would be even better if the company in question has other heat sources, allowing the water to be preheated to 100 degrees Celsius before being fed into the boiler, as this can effectively prevent oxygen corrosion of the boiler.
It is a feasible solution that can reduce the temperature difference stress between the pipeline and the boiler.
Yes, preheating the boiler feed water increases its temperature, which not only reduces the thermal stress at the inlet pipe of the boiler drum but also enhances the boiler’s output; meanwhile, the system’s energy-saving efficiency improves as well. However, this approach increases the risk of oxygen corrosion in the preheater. If the feedwater temperature is increased in front of the boiler’s economizer, the flue gas temperature can be raised, thereby reducing the likelihood of low-temperature corrosion in the tail ducts. Overall, it is highly beneficial for boiler operation. Keep it up, LZ. The operation of boilers involves various aspects, and there is much room for improvement during their operation.
This post was last edited by zjy_007 on 2009-5-9 at 10:22. There is a economizer; the maximum pressure is 1.2 Mpa, and the temperature reaches 100 degrees before the economizer. I’m mainly worried that too high a temperature might have an impact; I wonder if it can reach 100 degrees?
If 1.2 MPa is acceptable, it is necessary to ensure that the enthalpy at the exit of the economizer is 25 degrees. Otherwise, no vaporization will occur inside the boiler’s economizer, which poses a risk to the safety of the boiler.
7# feiyinglove: “The enthalpy at the outlet of the economizer is 25 degrees; otherwise, no vaporization will occur inside the boiler’s economizer.” What does that mean? I don’t quite understand it. How can vaporization take place inside the economizer?
Whether 100 degrees can be achieved depends on the flue gas temperature of the boiler; if possible, an air preheater can also be installed after the economizer.
Ours can reach 70 degrees; it mainly depends on what the flue gas temperature of the boiler can achieve, as well as on the size of the economizer’s heat exchange area A slightly higher inlet water temperature is still beneficial for the boiler.
Our factory has excess preheating capacity. The specific process is: tap water → soft water tank → economizer → boiler. In the soft water tank, the temperature reaches 100 degrees already, before reaching the economizer. I’m not sure if this is dangerous