Study of the Natural Circulation Heat Recovery Steam Generator Unsteady Behavior Using One Dimensional Model for the Evaporator Loop

Document Type : Research Article

Authors

1 Master of Science Graduate, Energy Conversion Department, Mechanical Engineering Faculty, Tarbiat Modares University, Tehran, Iran

2 Associate Professor, Energy Conversion Department, Mechanical Engineering Faculty, Tarbiat Modares University, Tehran, Iran

Abstract

Heat recovery steam generators as a vital part of cogeneration plants play a fundamental role in energy recovery processes. According to a necessity of accurate analysis of steam generators’ parameters variation rate to take a decision on steam generators processes such as start-up and shut-down, the present study aims to investigate the unsteady behavior of boilers using the dynamic simulation. In this respect, a one-dimensional model of the evaporator natural circulation loop along with boilers’ drum and heat transfer models are considered for simulation. Unsteady study scenarios include changes in the input heat to tube banks due to the change in the gas turbine load, feedwater flow rate and steam demand of the downstream cycle. A computer code has been developed to solve governing equations of a one- dimensional model and to demonstrate the response of boilers’ key parameters to different scenarios. Dynamic simulation results showed that a 5% increase in heat input to risers leads to an increase of 15% of the drum pressure as well as an increase of about 10 degrees of the tubes wall temperature. In addition, an increase of 20% in the heat input due to the change in the gas turbine load would increase the wall temperature of tubes by 35 degrees.

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References

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Amirkabir Journal of Mechanical Engineering
Volume 52, Issue 9
December 2020
Pages 2369-2386

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