Hai Everyone. I am fresh in the power industry. First time working in a combined cycle power plant. May I ask what does the means by HRSG heat soaking

Can the original poster try to respond to the last thread ...
It would be much appreciated ! as we are not here to discuss in the wind !

I mean we make effort to reply so please try to do the same...gentlemen.

Thank you for your attention& comprehension

James
 
Hai James,

Thank you for the informative article that you sent and I apologize for the delay in my response to your previous thread. However, I would like to point out that my initial question which referred to HRSG heat soaking was not answered in the article. Hope I could get a better clarification from you.
 
Hai James,

Thank you for the informative article that you sent and I apologize for the delay in my response to your previous thread. However, I would like to point out that my initial question which referred to HRSG heat soaking was not answered in the article. Hope I could get a better clarification from you.
Hai Tarsyanraj,

Thank you for your feedback!

This article was for a better obverview on CC operatings first ...
Here a article where "soaking time" for HRSG is clearly described during Unit startup.

Hope this can help!
James
 

Attachments

Steam turbines have a massive case compared to the rotor. Heat soaking allows for thermal expansion of the case and rotor to "grow" evenly. Differential expansion can cause the rotating portions of the turbine to "rub" against the stationary portions. Thermal expansion of steam and combustion turbines is a well known enemy of a turbine's lifetime.
 
Hai James,

Thank you for the informative article that you sent and I apologize for the delay in my response to your previous thread. However, I would like to point out that my initial question which referred to HRSG heat soaking was not answered in the article. Hope I could get a better clarification from you.
Tarsyanraj,


Here some notes from some inetresting documents about HRSG and CC operating principe& concepts:

Before an HRSG is put online, it is filled with water, and heat is applied. The cold metal takes some time to get heated, and time is required to soak the HRSG. The HRSG starts producing steam after a soaking period of a few minutes. If the steam is not released, then the pressure starts building up. The amount of steam produced and the increase in the pressure depend on the amount of heat supplied. More heat produces more steam, and pressure increases at a faster rate.
An HRSG without a bypass damper can be started in different ways depending on the operating philosophy and auxiliary support provided. Initially, when the CT is started and is picking up speed, the hot gases, which have a temperature of about 700F, pass through the HRSG and heat the metal and the cold water in the tubes. The CT startup period until the CT attains the synchronous speed is thus utilized as a soaking in time for the HRSG.
To keep the thermal stress within acceptable limits, the increase in water saturation temperature should be limited to manufacturer design specifications. Steam drums with thickness of 3" and higher are considered to be thick-walled drums that require soaking. In a combined cycle system, the CT by itself will not impose any restriction to the plant startup operation. Generally, the HRSG may impose a restriction (like drum soak), only during cold startup of the plant. In warm start, the drum soak time will be minimal, and will require adjustments in the startup rate of individual CT and HRSG components and should be modified to match the load distribution requirements. Soak time will not typically be required during a plant hot start plant startup. To this effect, a plant startup curve for each style of startup (cold, warm, hot) should be prepared for the operators' benefit by integrating and modifying individual component startup curves. During initial startup, the HRSG system should be checked and confirmed to have no restrictions for thermal growth and movements of pressure parts (modules, pipes, etc.) and nonpressure parts (duct columns, etc.). Avoid trapping steam in the economizer by venting to the HP steam drum, using the valve located near the HP drum.


So have a good read !

I am sure that it can highlight you and help you to understand this concept!


James
 
Soak time will not typically be required during a plant hot start plant startup. To this effect, a plant startup curve for each style of startup (cold, warm, hot) should be prepared for the operators' benefit by integrating and modifying individual component startup curves. During initial startup, the HRSG system should be checked and confirmed to have no restrictions for thermal growth and movements of pressure parts (modules, pipes, etc.) and nonpressure parts (duct columns, etc.). Avoid trapping steam in the economizer by venting to the HP steam drum, using the valve located near the HP drum.
 
Thread starter Similar threads Forum Replies Date
R General Automation Chat 1
Top