For the control of the outlet temperature of the heating furnace, should the parameter in the secondary circuit be the gas pressure or the gas flow rate?
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This post was last edited by 328104062 on 2012-12-25 22:14. As the title suggests, what is the difference between using pressure control and flow control as the secondary loop? ? ? ? Take a look at our furnaces: one is a atmospheric pressure furnace that burns gas (or oil), with the auxiliary controller regulating the gas flow; the other is a steam superheating furnace that also burns gas, with the auxiliary controller controlling the gas pressure. Both furnaces have negative pressure chambers, and they are equipped with blowers and exhaust fans. They look pretty similar
This is determined by the manufacturing process, and factors such as the influence of secondary parameters on the main parameter, the detection of secondary parameters, and the relationship between the measured values and the main parameter need to be taken into account. Personally, I think it’s the gas flow rate.
Gas pressure is related to the shape and stiffness of the flame, right? Gas flow rate is related to the calorific value. The heating furnace should have temperature control; in that case, the calorific value should be more direct to determine.
Some of our furnaces have pressure controllers in their secondary circuits, while others use flow controllers. I’m not sure why there’s a difference ? ? ? ? ? ? ? ? ? ?
Our furnaces are controlled via flow regulation, but it hasn’t been implemented yet – the flow meters keep breaking down
It depends on which parameter is more stable; it can be adjusted, right? For example, if flow rate was used previously and there are many impurities in the gas, a stable flow rate does not guarantee a stable calorific value. I’ll go with pressure after all. The same is true in reverse. There isn’t a uniform model for each factory, right?
Controlling pressure is, in fact, controlling flow rate—for burners and the pipeline section downstream of the valve, their resistance characteristics are fixed; therefore, increases or decreases in pressure directly determine corresponding increases or decreases in gas flow rate.
We also use a secondary controller for flow control. As for the reasons, I think the other users up above have already discussed them in great detail; it was very informative!
Is it the same type of furnace? Since the furnaces operate in different ways, their control methods must also be different. You had better specify the type of furnace and its operating mechanism. In this way, netizens in the same industry will be able to provide more targeted answers.
One is a atmospheric-pressure furnace that burns gas (or oil), with the auxiliary controller being the gas flow rate; the other is a steam superheating furnace that also burns gas, with the auxiliary controller being the gas pressure. Both furnaces have negative-pressure chambers, and they are equipped with blowers and exhaust fans. They look similar in appearance
As I recall, the secondary loop of cascade control is mainly used to increase the control speed. The temperature of a heating furnace is a physically quantity with large lag, so cascade control is often employed. The secondary circuit is used for pressure regulation; this generally indicates that the fuel pressure is not very stable, which in turn causes fluctuations in temperature. The secondary circuit is used for flow regulation; generally, this indicates that the fuel flow is not very stable, which in turn leads to temperature fluctuations. The different control methods may be related to the different fuel supply methods for the two furnaces in your plant.