How does the pressure in a steam header react to a sudden load change?

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Discussion Overview

The discussion revolves around the effects of sudden load changes on the pressure in a steam header within a steam power plant. Participants explore the relationship between pressure variations and the operational dynamics of the system, including the response of the control system and the implications for turbine performance.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Chandu inquires about how a sudden increase in load affects the pressure in the steam header and its influence on the overall process.
  • One participant suggests that pressure can be modeled as the integral of the mismatch between energy in and energy out, noting that energy storage is influenced by both temperature and pressure.
  • A follow-up question raises concerns about the potential delay in the control system's response to changes in energy demand and its effect on pressure stability.
  • Another participant confirms that there is a mathematical relationship between pressure drop in the header and turbine output, indicating that turbine power is proportional to pressure times mass flow rate.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding regarding the relationship between pressure changes and system dynamics. While some concepts are acknowledged, there is no consensus on the specifics of the pressure's impact on the process or the exact nature of the mathematical relationships involved.

Contextual Notes

The discussion includes assumptions about system behavior, such as the constancy of temperature in simplified models, and acknowledges the complexity of the control system's response time, which remains unresolved.

Who May Find This Useful

Individuals interested in steam power plant operations, control systems in thermal dynamics, and the mathematical modeling of energy systems may find this discussion relevant.

Chandrakanth_balusa
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Hello People,
I have querry regarding the pressure variation in the steam header in the steam power plant.
if there is a sudden change in the load and the mass flow through the turbine has to be increased, i would like to know how it effects the pressure value? if yes how does this change influence the process?

could you also suggest me a nice resoure where I can study about the header and it operation.

thanks in advance

BR

Chandu
 
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This is probably a drum type boiler.

A simplified model would be to think of pressure as the integral of the mismatch between energy in and energy out. Actually, energy storage depends on both temperature and pressure, but in a simplified model, imagine temperature to be constant.

So what happens when you make a step change in energy out?

How does the control system respond to change the energy in? How long does that take?
 
anorlunda said:
This is probably a drum type boiler.

A simplified model would be to think of pressure as the integral of the mismatch between energy in and energy out. Actually, energy storage depends on both temperature and pressure, but in a simplified model, imagine temperature to be constant.

So what happens when you make a step change in energy out?

How does the control system respond to change the energy in? How long does that take?
so I understand from you response that the pressure is a function of energy in and out.
but if the pressure in the header varies, does it effect the process? I know that this variation is going to be for a very short time since the control system triggers the energy in based on the energy out value.

i am a bit curious to know what if the boiler takes a bit long to serve the energy in and the pressure in the header goes on reducing. mathematically is there any relation between pressure drop in the header and the output f turbine or torque or speed.

thanks in advance
 
Chandrakanth_balusa said:
mathematically is there any relation between pressure drop in the header and the output f turbine or torque or speed.

Yes. Again speaking in very approximate numbers, turbine power is proportional to presssure times mass flow rate
 

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