If the steam boiler is used at reduced pressure, what will happen to the evaporation volume?
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This issue has also been discussed in the forum, but I feel it is not profound enough. I am also very confused about this issue. I hope that experienced friends, especially those from boiler manufacturers, will actively discuss it.: What will be the impact on the evaporation volume of a steam boiler after its pressure is reduced? For example, if a steam boiler of a certain tonnage with a rated pressure of 2.45MPa is used at a working pressure of 1.2MPa, will its evaporation volume increase? The excess evaporation volume is calculated based on the total heating heat balance. Or will the efficiency of the boiler decrease and the maximum evaporation capacity be calculated based on the tonnage with 10% overload? Please give me your best regards. Additional information: Boilers are mainly used for heating and saturated steam pressure. For example, some devices are out of production, and the steam pressure used by some other products is not high. This post was last posted by * Edited by eqiguo on 2008-11-10 13:19 ]
I personally think that boiler pressure reduction operation is feasible, and our factory has made some attempts in this regard. Mainly from the perspective of energy saving and plant-wide steam system balance, the evaporation volume will increase after pressure reduction operation while the fuel remains unchanged.
If the pressure is reduced, the quality of the steam will decrease, but the ratio of steam volume to coal combustion volume can be increased. It depends on whether you mainly provide heat or generate electricity.
The initial result of boiler depressurization operation must be an increase in evaporation. personal opinion
I’ll give you a rough answer first and then take a closer look when I come back tonight. Personally, I think the amount of steam will increase when the pressure is reduced. Because the temperature of the saturated steam decreases, the amount of steam will increase. Thermal efficiency requires further calculation. However, the feed water temperature should be changed when the pressure is reduced, otherwise the superheated steam temperature will be too high. It will also increase the exhaust smoke temperature. As for the specific thermal efficiency, I hope you can elaborate on the technical indicators you plan to change or introduce your current specific situation clearly, so that you can calculate it from the perspective of thermal efficiency.
According to the heat balance calculation, the evaporation amount should have increased, but in fact, in order to control the furnace tube temperature, the cycle rate will increase, and I think it is uncertain whether the evaporation amount will increase. Please ask Haiyou with practical operation experience to add, and the thermal efficiency of the boiler must have decreased, which is reflected in the increase in the exhaust gas temperature.
I think the steam volume will increase during decompression operation. Since the saturated steam temperature decreases and the latent heat of vaporization decreases, the steam volume will increase under the same heat absorption condition.
The evaporation capacity of the boiler cannot be increased much when the pressure is reduced, but the temperature of the steam decreases.
Our boilers also operate at reduced pressure, with rated pressure: 12.5MPa, working pressure: 8MPa, the steam volume will increase, but not by much.
During actual use, when the boiler is operated at reduced pressure, there is no significant increase in evaporation. At least I did not find any significant increase during the reduced pressure operation. The temperature of the superheated steam will drop, but not by much.
The efficiency must have dropped, or there is a rated working condition. If it deviates too much from the design working condition, it will definitely be poor. How does the voltage reduction operation work?