A thermal nonlinear dynamic model for water tube drum boilers

Habib, Mohamed A.; Emara-Shabaik, Hosam E.; Al-Zaharnah, I.; Ayinde, T.

doi:10.1002/er.1548

Cited by 7 publications

(7 citation statements)

References 24 publications

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“…The initial value S 0 is constant and is independent of the location of r. The influence function u(r, t) allows to determine thermal stress S(r P ,t) for any continuous change of the medium temperature f(t), using Duhamel's integral, defined by Equation (2). The influence function u(r P ,t) at the points P 1 and P 2 describes the change of circumferential stresses at the edge of the opening, caused by a unit, stepwise increase of the fluid temperature.…”

Section: Mathematical Formulation Of the Methodsmentioning

confidence: 99%

“…Bi 5 Biot number, Bi 5 hL/k c 5 specific heat capacity (J kg À1 K À1 ) D 5 inner diameter of the drum (m) E 5 modulus of elasticity (MPa) f 5 fluid temperature (1C) F 5 number of future time steps F(x,t) 5 solution of the initial-boundary problem Fo 5 Fourier number, Fo 5 at/L 2 F, F 1 5 functions defined by Equations (21) and (22) h 5 heat transfer coefficient (W m À2 K À1 ) H, h 5 thickness of the drum and downcomer wall (m) k 5 thermal conductivity (W m À1 K À1 ) L 5 slab thickness (m) n t 5 number of time points p n 5 gauge pressure (MPa) p 1 5 initial pressure during start-up or shutdown of the boiler (MPa) p 2 5 final pressure during start-up or shutdown of the boiler (MPa) r 5 radius (m) r 5 position vector S 5 stress calculated using Duhamel integral (MPa) S e 5 sum of the temperature difference squares (K 2 ) t 5 time (s) T 5 temperature (1C or K) T 5 mean temperature over the wall thickness (1C) u 5 influence function (temperature or thermal stress for unit stepwise increase of the fluid temperature) U 5 uncertainty v T 5 rate of temperature changes (K s À1 ) x 5 cartesian coordinate (m) y 5 allowable stress (MPa)…”

Section: Nomenclaturementioning

confidence: 99%

“…Rapid startups and shutdowns of the steam boilers cause excessive thermal stresses in thick-walled pressure components [1][2][3]. Remnant life of the pressure components can be significantly reduced if the heating or cooling rates are too high.…”

Section: Introductionmentioning

confidence: 99%

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A new method for optimum heating of steam boiler pressure components

Taler

Dzierwa

2010

Int. J. Energy Res.

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SUMMARYA method for determining time-optimum medium temperature changes is presented. The heating and cooling of the pressure elements will be conducted in such a way that the circumferential stresses caused by pressure and fluid temperature variations at the edge of the opening and point of stress concentration do not exceed the allowable values. However, the calculated optimum temperature changes are difficult to follow in practice during the initial stage of heating. Nevertheless, it is possible to increase the fluid temperature stepwise to the minimum value and then heat the pressure component according to the determined optimum temperature changes. Allowing stepwise fluid temperature increase at the beginning of heating ensures that the heating time of a thick-walled component is shorter than the heating time resulting from the calculations according to EN 12952-3 European Standard or TRD 301 (Technische Regeln fu¨r Dampfkessel) regulations.

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Section: Mathematical Formulation Of the Methodsmentioning

confidence: 99%

Section: Nomenclaturementioning

confidence: 99%

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A new method for optimum heating of steam boiler pressure components

Taler

Dzierwa

2010

Int. J. Energy Res.

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“…CFD calculations for fuel-air mixtures were conducted by Mahesh et al [56] Mohanraj et al [58], Habib et al [59,60]. Mahesh et al [56] developed a numerical method using LES for simulating turbulent Figure 7.…”

Section: Cfd Calculations Of Oxyfuel Combustionmentioning

confidence: 99%

A review of recent developments in carbon capture utilizing oxy-fuel combustion in conventional and ion transport membrane systems

Habib

Badr

Ahmed

et al. 2010

Int. J. Energy Res.

Self Cite

170

102

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SUMMARYFossil fuels provide a significant fraction of the global energy resources, and this is likely to remain so for several decades. Carbon dioxide (CO 2 ) emissions have been correlated with climate change, and carbon capture is essential to enable the continuing use of fossil fuels while reducing the emissions of CO 2 into the atmosphere thereby mitigating global climate changes. Among the proposed methods of CO 2 capture, oxyfuel combustion technology provides a promising option, which is applicable to power generation systems. This technology is based on combustion with pure oxygen (O 2 ) instead of air, resulting in flue gas that consists mainly of CO 2 and water (H 2 O), that latter can be separated easily via condensation, while removing other contaminants leaving pure CO 2 for storage. However, fuel combustion in pure O 2 results in intolerably high combustion temperatures. In order to provide the dilution effect of the absent nitrogen (N 2 ) and to moderate the furnace/combustor temperatures, part of the flue gas is recycled back into the combustion chamber. An efficient source of O 2 is required to make oxycombustion a competitive CO 2 capture technology. Conventional O 2 production utilizing the cryogenic distillation process is energetically expensive. Ceramic membranes made from mixed ion-electronic conducting oxides have received increasing attention because of their potential to mitigate the cost of O 2 production, thus helping to promote these clean energy technologies. Some effort has also been expended in using these membranes to improve the performance of the O 2 separation processes by combining air separation and high-temperature oxidation into a single chamber. This paper provides a review of the performance of combustors utilizing oxy-fuel combustion process, materials utilized in ion-transport membranes and the integration of such reactors in power cycles. The review is focused on carbon capture potential, developments of oxyfuel applications and O 2 separation and combustion in membrane reactors. The recent developments in oxyfuel power cycles are discussed focusing on the main concepts of manipulating exergy flows within each cycle and the reported thermal efficiencies.

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“…In literature, there are found many mathematical models for simulating the dynamic behaviour of steam power plants. For example, Elmegaard (1999), Diaz (2003) and Habib et al (2010) present dynamic models. In this work, the aim is to develop the dynamic model of the supercritical circulating fluidized bed (CFB) Benson type once-through utility (OTU) boiler.…”

Section: Introductionmentioning

confidence: 99%