A Generalized Dynamic Water Side Model for a Once-Through Benson Boiler

Yli-Fossi, Timo; Köykkä, Petri; Majanne, Yrjö

doi:10.3182/20110828-6-it-1002.01909

Cited by 4 publications

(2 citation statements)

References 7 publications

(8 reference statements)

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“…The model block calculates time derivatives of metal and refractory walls temperatures. (Yli-Fossi et al, 2011;Yli-Fossi et al, 2012) Pressure point model block calculates time derivatives of pressure and outlet fluid mass flow(s). The calculation of pressure [Pa] for single-phase water and steam is based on the following equation (Lu, 1999) The time derivative of pressure for two-phase liquid and vapour mixture can be calculated as (Lu, 1999 .…”

Section: Basic Process Componentsmentioning

confidence: 99%

Functionality Testing of Water Pressure and Flow Calculation for Dynamic Power Plant Modelling

Yli-Fossi¹

2018

Linköping Electronic Conference Proceedings

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Water pressure and flow rate calculation in dynamic boiler models is challenging because of stiff system dynamics meaning that time constants of model states vary by several orders of magnitude. Furthermore, strong interconnections between pressures and flow variables may cause instability problems in simulation runs. This study presents a method to implement and test dynamic thermal power plant water-steam system models. A dynamic water-steam system model is presented. The model is applied for testing of the functionality of the presented computation model. Computational performance was tested using different numerical solvers. Also sensitivity to changes in initial values of system states and model parameters was tested. The results indicate that a workable way to make flexible models was found.

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Section: Basic Process Componentsmentioning

confidence: 99%

Functionality Testing of Water Pressure and Flow Calculation for Dynamic Power Plant Modelling

Yli-Fossi¹

2018

Linköping Electronic Conference Proceedings

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“…5 Further, development cases of in-house codes using physics-based models have been reported for the dynamic prediction of the steam flow of the OTU boiler. 6–9 Meanwhile, various CFB FUR models were introduced to simulate the solid–gas flow inside the FUR. 10–12 To predict the performance of a CFB FUR with a drum-loop-type steam generator, dynamic models have been developed to simulate the heat transfer from the solid–gas flow to the water–steam flow.…”

Section: Introductionmentioning

confidence: 99%

Dynamic simulation study of the steam temperature in a ultra-supercritical circulating fluidized bed boiler system

Kim

Choi

Song

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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A dynamic simulation of a modern ultra-supercritical circulating fluidized bed (USC-CFB) boiler system was performed using a physics-based model, where the boiler system was composed of an integrated system of heat exchanger (HEX) blocks. In each of the discretized elements of the HEX blocks, supercritical steam flow interacted with the solid–gas flow via heat transfer, and conservation laws, and physical phenomena of the CFB, and the supercritical steam flow was modeled to obtain the flow properties of each material side. By utilizing this model, the dynamic behavior of the main steam temperature, which was selected as the representative performance parameter for achieving safe and fast load changes, was simulated in response to changes applied to the main operating parameters such as the feedwater and fuel flow rates. The dynamic characteristics of the USC-CFB boiler were demonstrated by presenting the temperature responses of the steam and the circulating solid–gas after a step change in the feedwater and fuel flow rates. In the case of a load change, the dynamic response of the steam temperature was quantitatively presented by showing the transient overshoot and undershoot behavior, depending on the selection of the ramp speed when changing the feedwater and fuel flow rates. The steam temperature was also shown to be controlled by manipulating the inlet solid mass flow rate into the final superheater section of the external HEX. The comprehensive set of plant performance data that was generated from the model simulation can be utilized in setting up the operation strategies and/or in determining the control parameters for achieving stable steam temperature behavior during a load change.

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