Coupled fluid dynamics and whole plant simulation of coal combustion in a tangentially-fired boiler

Calculations of PHEBUS FPT-1 are performed in the frame of CSNI International Standard Problem ISP-46. The objective of ISP-46 is to assess the capability of computer codes to provide an integral simulation of a severe accident in a Pressurised Water Reactor (PWR), from the initial stages of core heat-up to the behaviour of released fission products in the containment. The present calculations are performed using MELCOR, chosen as the main tool for assessment of Swiss nuclear plants by virtue of its whole-plant simulation capability, using modelling practices as similar as possible to those used in plant analyses. The calculations cover the bundle heat-up, degradation, the release, transport and retention of fission products and other materials, and the thermal-hydraulic and aerosol behaviour in the containment. Comparison between a best-estimate case and experiment demonstrates the code’s ability to capture most aspects of the sequence with fair to good accuracy. Uncertainties remain, particularly in regard to core degradation, and the chemistry and transport of fission products. Weaknesses of code models in these areas largely reflect limitations in current knowledge.

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Two-dimensional computational fluid dynamics simulation of coal combustion in a circulating fluidized bed combustor

Chemical Engineering Journal ◽

10.1016/j.cej.2010.09.048 ◽

2011 ◽

Vol 166 (1) ◽

pp. 306-314 ◽

Cited By ~ 54

Author(s):

W. Zhou ◽

C.S. Zhao ◽

L.B. Duan ◽

C.R. Qu ◽

X.P. Chen

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Fluidized Bed ◽

Coal Combustion ◽

Circulating Fluidized Bed ◽

Dynamics Simulation ◽

Two Dimensional ◽

Computational Fluid Dynamics Simulation ◽

Fluidized Bed Combustor

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Computational fluid dynamics applied to a cement precalciner

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1243/0957650001538353 ◽

2000 ◽

Vol 214 (3) ◽

pp. 269-280 ◽

Cited By ~ 9

Author(s):

D Giddings ◽

C N Eastwick ◽

S J Pickering ◽

K Simmons

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Calcium Oxide ◽

Coal Combustion ◽

Reaction Rate ◽

Gas Flows ◽

Coal Particles ◽

Computational Fluid Dynamics Cfd ◽

Burning Coal ◽

Future Work

This paper describes a study of the use of computational fluid dynamics (CFD) to investigate the performance of a precalciner vessel at a cement works, In this vessel, limestone, held in suspension, is calcined to calcium oxide and the endothermic reaction is supported by the combustion of coal. Results are presented from a CFD model that contains all the essential features of the precalciner as operated when burning coal. The model fully represents the reactions and fluid dynamics of the precalciner. Previously unidentified features are illustrated. Certain key features at points in the precalciner, where some limited measurements can be made, are compared with the parameters indicated by the computational model. The measurements are consistent with the results calculated by the model indicating fair validation. The CFD data show the following 1 The gases undergo distinct recirculation. 2 The coal particles entering at one inlet have significantly different trajectories and temperature histories from those entering at the second diametrically opposed inlet. 3 There is 90 per cent completion of coal combustion at the exit. 4 73 per cent limestone in the raw meal is calcined to calcined to calcium oxide at the exit from the precalciner. 5 The highest reaction rate of the raw meal is closer to one side of the vessel due to interaction with the gas flows. Future work is proposed which, firstly, will provide further validation of the results so far attained by selective measurements on the precalciner and, secondly, will model the combustion and aerodynamic behaviour of waste-derived fuels in the precalciner vessel, commencing with shredded car tyre chips.

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Reducing Operating Cost With Anammox In Wastewater Treatment -- A Simulation Study

10.32920/ryerson.14662002 ◽

2021 ◽

Author(s):

Eliav J. Eini

Keyword(s):

Total Nitrogen ◽

Simulation Study ◽

Operating Cost ◽

Operational Strategies ◽

Reduce Operating Cost ◽

Start Up ◽

Whole Plant ◽

Plant Simulation ◽

Biological Nitrogen ◽

Anammox Process

A simulation study is presented to investigate the use of the Anammox process for removing nitrogen compounds from wastewater to reduce operating cost. The literature review of technologies for removal of Total Nitrogen includes an overview of the biological nitrogen cycle, the discovery of Anammox, bioreactor design, operational strategies, and start-up of full-scale processes. A facility of 656 MLD with influent loading of 35 mg/L as NH3-N and 250 mg/L as BOD is used as a basis of the simulation study. Preliminary bioreactor sizing calculations are developed for six configurations. Subsequently, eight whole-plant simulation cases are compared to demonstrate operational savings for removal of Total Nitrogen. For the sample facility, this is shown to be on the order of $460 to $680K/year while attaining 66-70% Total Nitrogen removal and reduced greenhouse gas emissions by 2 kt CO2/year. The project concludes with ideas about future development of the Anammox process.

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