Numerical simulation of convective superheaters in steam boilers

Taler, Dawid; Trojan, Marcin; Dzierwa, Piotr; Kaczmarski, Karol; Taler, Jan

doi:10.1016/j.ijthermalsci.2018.03.005

Cited by 49 publications

(15 citation statements)

References 30 publications

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“…It is created as a result of coal combustion in furnaces and captured from a dynamic exhaust stream by electrostatic or mechanical dedusting devices [4][5][6][7]. In coal-fired power plants, the deposition of slug and fly ashes on heating surfaces such as combustion chamber walls and plate superheaters is a very serious problem [8][9][10]. This problem has become even more serious in recent years due to the necessity of co-combustion of biomass [11].…”

Section: Introductionmentioning

confidence: 99%

The influence of compaction and saturation on the compressibility of colliery waste

Kamińska¹,

Dzierwa

2019

THERM SCI

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Original scientific paper https://doi.org/10.2298/TSCI19S4345KUsing colliery waste to produce building materials, especially in earthworks to build different types of road and railway embankments, or to fill cavities and open-pit mines, requires us to determine the value of the settlement and the ability of fly ash to reduce its volume about its usability for mentioned purposes. Economic benefits and the need to protect the environment are the main reasons for using fly ash as secondary raw material. The purpose of this paper is to determine the effect of initial compaction and water conditions on the process and values of settlement as well as oedometric modulus of primary compression, decompression and secondary compression of fly ash. The tests were carried out in oedometers. The subject of the research was fly ash from Skawina Power Plant. Literature analysis covers the processes of waste production and management, types of waste depending on the grain size and composition, as well as the methods and ways of testing the compressibility of mineral and anthropogenic soils. The results of the tests allowed formulating conclusions on the influence of compaction and water conditions on the possibility of settling, consolidation and the values of compressibility moduli of the tested material. They also allowed determining the usability of the material for earth constructions and other purposes.

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Section: Introductionmentioning

confidence: 99%

The influence of compaction and saturation on the compressibility of colliery waste

Kamińska¹,

Dzierwa

2019

THERM SCI

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“…Molten ash, i. e. slag, is deposited on the heating surfaces of the boiler when the flue gas temperature exceeds 1200 °C. The heat-flow rate absorbed by the evaporator and superheaters can be assessed by calculating the following two indicators in on-line mode: sup can be used to determine of the superheater ash fouling degree [12], because the fouled superheater absorbs a lower heatflow rate compared to the heat-flow rate absorbed by the clean superheater at the same live steam mass-flow. In the case of an evaporator, the factor  ev is equal to one, regardless of whether the walls of the evaporator are slagged or not.…”

Section: Assessment Of the Degree Of Water Walls Slagging And Ash Foumentioning

confidence: 99%

On-line monitoring of the fouling of the boiler heating surfaces

2019

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Original scientific paper https://doi.org/10.2298/TSCI19S4289TThe designed system for the monitoring of the fouling of the furnace and superheaters/reheaters, presented in the paper, will make it possible to operate the boiler with high efficiency. Measurements of temperatures, pressures, flows, and gas analysis data are used to perform heat transfer analysis in the boiler furnace and evaporator. Power boiler efficiency is calculated by an indirect method. The local and average degree of the combustion chamber slagging is determined in an "on-line" mode. In the case of superheaters, the fouling coefficient is determined for each superheater stage, due to big differences in ash-related fouling of individual stages. Fouling processes deteriorate the boiler capacity and efficiency and increase the rate of corrosion of the boiler heating surfaces. The energy consumption of flue gas fans rises as well because the accumulation of slag and ash involves higher pressure losses at individual superheater stages. In addition, examples of ash fouling of individual boiler heating surfaces are presented and discussed in the paper.

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“…where the symbol  designates the gamma function [22]. The economizer was modeled in the same way as the superheaters, using the developed distributed parameter mathematical model proposed in [23,24]. The general assumptions made in the development of a numerical model of the boiler economizer are as follows: the water and gas flow is one dimensional, the physical properties of fluids are functions of temperature, axial heat conduction in the tube wall and fluid is negligible, the temperature and flue gas velocity are constant over the channel cross-section before the economizer, and heat transfer coefficients on the inner and outer tube surfaces are uniform.…”

Section: Mathematical Model Of the Boiler Economizermentioning

confidence: 99%

“…-(23), and(24) for the temperatures at nodes in steam, wall, and flue gas areas was solved by the Gauss-Seidel method. Finite control volume: (a) for the flue gas and steam (b) for the tube wall.…”

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Modeling of the boiler economizer

Trojan

Granda

2018

MATEC Web Conf.

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The boiler economizer is a tube heat exchanger located in the final part of the convective duct. In the economizer, water flowing into the boiler is preheated by flue gases. The paper presents the boiler economizer mathematical model with distributed parameters, which can be used to simulate its operation. The developed mathematical model makes it possible to determine temperatures of the tube and working medium of the boiler economizer. In addition, the non-linear mathematical model of the entire boiler allows to analyze the influence of ash fouling of individual boiler heating surfaces on the economizer operation. The proposed model can also be used for monitoring heat and flow parameters of the economizer in on-line mode.

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Numerical simulation of convective superheaters in steam boilers

Cited by 49 publications

References 30 publications

The influence of compaction and saturation on the compressibility of colliery waste

The influence of compaction and saturation on the compressibility of colliery waste

On-line monitoring of the fouling of the boiler heating surfaces

Modeling of the boiler economizer

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