scholarly journals Simulation of Thermal Effects on the Flow Field in a Pilot-Scale Kiln

2021 ◽  
Author(s):  
I. A. Sofia Larsson ◽  
Anna-Lena Ljung ◽  
B. Daniel Marjavaara
Keyword(s):  
Flow Field ◽  
Coal Combustion ◽  
Thermal Effects ◽  
Iron Ore ◽  
Combustion Process ◽  
Pilot Scale ◽  
Mixing Properties ◽  
Process Gas ◽  
Mixing Rates ◽  
Computational Fluid Dynamics Cfd

AbstractThe flow field and coal combustion process in a pilot-scale iron ore pelletizing kiln is simulated using a computational fluid dynamics (CFD) model. The objective of the work is to investigate how the thermal effects from the flame affect the flow field. As expected, the combustion process with the resulting temperature rise and volume expansion leads to an increase of the velocity in the kiln. Apart from that, the overall flow field looks similar regardless of whether combustion is present or not. The flow field though affects the combustion process by controlling the mixing rates of fuel and air, governing the flame propagation. This shows the importance of correctly predicting the flow field in this type of kiln, with a large amount of process gas circulating, in order to optimize the combustion process. The results also justify the use of down-scaled, geometrically similar, water models to investigate kiln aerodynamics in general and mixing properties in particular. Even if the heat release from the flame is neglected, valuable conclusions regarding the flow field can still be drawn.

Experimental Study on the Effects of Declivitous Angle of Secondary Air on the Flow Characteristics and Coal Combustion of a Down-Fired

2011 ◽  
Author(s):  
Jian Shi ◽  
Yuzhong Chen ◽  
Yubo Hou ◽  
Bin Yao
Keyword(s):  
Fly Ash ◽  
Flow Field ◽  
Carbon Content ◽  
Coal Combustion ◽  
Field Experiments ◽  
Combustion Process ◽  
Flow Characteristics ◽  
Cold Flow ◽  
Horizontal Momentum ◽  
Secondary Air

Aiming at Foster Wheeler (FW) technology down-fired boiler with horizontal F layer secondary air, in which the strong horizontal momentum of the secondary air seriously pounds the down flowing coal gas flame, making the problems of short trip of coal flame and low flame fullness of the furnace, and this leads to higher carbon content of fly ash and so on. A designed adjusting device making the declivitous angle of secondary air is erected in the F layer wind box of a FW down-fired furnace, so the declivitous angle of secondary air can be regulated freely. By this means, the declivitous angle of the F layer secondary air is able to be refined depending on the real combustion situation to achieve the best configuration of the momentum radio by downward momentum from the arch and horizontal momentum from the front/rear wall. As a result, it is able to adapt the change of the furnace combustion situation, extending the flame travel, and improving the combustion process and efficiency. This method was applied to a 300MW grade FW down-fired boiler, and the cold flow field results by fireworks showed the down flow depth of the primary air increasing with the declivitous angle. The best flow field was achieved as the declivitous angle was set to 45°. Based on the cold flow field experiments, combustion experiment was accomplished to compare with the coal combustion performance before the declivitous refinement of the F layer secondary air. It was shown that the carbon content of the fly ash was greatly decreased after the refinement, and the combustion efficiency was increased by 3.3%.

scholarly journals The Effect of Oxygen Staging on Nitrogen Conversion in Oxy-Fuel CFB Environment

2014 ◽  
Vol 35 (4) ◽  
pp. 489-496 ◽  
Author(s):  
Sylwia Jankowska ◽  
Tomasz Czakiert ◽  
Grzegorz Krawczyk ◽  
Paweł Borecki ◽  
Łukasz Jesionowski ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Oxygen Content ◽  
Flue Gas ◽  
Coal Combustion ◽  
Combustion Process ◽  
Pilot Scale ◽  
Control Points ◽  
Nitrogen Conversion ◽  
Gas Measurements ◽  
Effect Of Oxygen

Abstract This paper presents a study on nitrogen conversion in oxy-fuel coal combustion in a pilot scale CFB 0.1 MWth facility. The paper is focused on fuel-N behaviour in the combustion chamber when the combustion process is accomplished under oxy-fuel CFB conditions. The analysis is based on infurnace sampling of flue gas and calculations of the conversion ratios of fuel-nitrogen (fuel-N) to NO, NO2, N2O, NH3 and HCN. For the tests, O2/CO2 mixtures with the oxygen content of 21 vol.% (primary gas) and with the oxygen content varied from 21 to 35 vol.% (secondary gas), were used as the fluidising gas. Measurements were carried out in 4 control points located along the combustion chamber: 0.43 m, 1.45 m, 2.50 m and 4.88 m. Results presented below indicate that an increased oxygen concentration in the higher part of the combustion chamber has strong influence on the behaviour of fuel based nitrogen compounds.

Thermal effects on arsenic emissions during coal combustion process

2018 ◽  
Vol 612 ◽  
pp. 582-589 ◽  
Author(s):  
Weiqiang Zhang ◽  
Qiang Sun ◽  
Xiuyuan Yang
Keyword(s):  
Coal Combustion ◽  
Thermal Effects ◽  
Combustion Process

scholarly journals Combustion Enhancement of Pulverized Coal with Targeted Oxygen-Enrichment in an Ironmaking Blast Furnace

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 440
Author(s):  
Zhenfeng Zhou ◽  
Ruihao Wang ◽  
Qiujie Yi ◽  
Guang Wang ◽  
Chunyuan Ma
Keyword(s):  
Blast Furnace ◽  
Coal Combustion ◽  
Particle Temperature ◽  
Combustion Process ◽  
Oxygen Enrichment ◽  
Oxygen Utilization ◽  
O2 Concentration ◽  
Computational Fluid Dynamics Cfd ◽  
Enrichment Technology ◽  
Cfd Method

In this study, a targeted oxygen-enrichment technology was proposed to enhance coal combustion in an ironmaking blast furnace. The coal flow and combustion characteristics under targeted oxygen-enrichment were investigated using the computational fluid dynamics (CFD) method. The results showed that oxygen utilization and coal burnout were significantly increased under targeted oxygen-enrichment. The coal burnout at 24% O2 concentration was 86.29%, which was the maximum and indicated an increase of 13.13%. However, the cooling effect of room-temperature oxygen had some adverse effects on coal combustion. Given this, the effect of coal particle temperature on coal combustion was investigated based on targeted oxygen-enrichment. The coal combustion process was further enhanced. The coal burnout at a 600 K particle temperature and 25% oxygen concentration was 91.12% and had an increase of 17.96%, which was the maximum.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

scholarly journals Rheological Properties of Wood–Plastic Composites by 3D Numerical Simulations: Different Components

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 417
Author(s):  
Xingcong Lv ◽  
Xiaolong Hao ◽  
Rongxian Ou ◽  
Tao Liu ◽  
Chuigen Guo ◽  
...  
Keyword(s):  
Flow Field ◽  
Rheological Properties ◽  
Wood Fiber ◽  
Velocity Shear ◽  
Wood Plastic Composites ◽  
Shear Rates ◽  
Plastic Composites ◽  
Power Law Fluids ◽  
Field Information ◽  
Computational Fluid Dynamics Cfd

The rheological properties of wood–plastic composites (WPCs) with different wood fiber contents were investigated using a rotational rheometer under low shear rates. The flow field information was analyzed and simulated by Ansys Polyflow software. The results showed that the WPCs with different wood fiber contents behaved as typical power-law fluids. A higher wood fiber content increased the shear thinning ability and pseudoplasticity of the WPCs. The pressure, velocity, shear rate, and viscosity distributions of the WPC during extrusion could be predicted by computational fluid dynamics (CFD) Ansys Polyflow software to explore the effects of different components on the flow field of WPCs.

Analysis of Single- and Two-Phase Flows in Turbopump Inducers

1967 ◽  
Vol 89 (4) ◽  
pp. 577-586 ◽  
Author(s):  
P. Cooper
Keyword(s):  
Equation Of State ◽  
Flow Field ◽  
Thermal Effects ◽  
Single Phase ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Recent Theory ◽  
Two Phase ◽  
Overall Efficiency

A model is developed for analytically determining pump inducer performance in both the single-phase and cavitating flow regimes. An equation of state for vaporizing flow is used in an approximate, three-dimensional analysis of the flow field. The method accounts for losses and yields internal distributions of fluid pressure, velocity, and density together with the resulting overall efficiency and pressure rise. The results of calculated performance of two sample inducers are presented. Comparison with recent theory for fluid thermal effects on suction head requirements is made with the aid of a resulting dimensionless vaporization parameter.

Construction Ventilation Scheme Optimization of Underground Main Powerhouse Based on CFD

2013 ◽  
Vol 368-370 ◽  
pp. 619-623
Author(s):  
Zhen Liu ◽  
Xiao Ling Wang ◽  
Ai Li Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Air Flow ◽  
Scheme Optimization ◽  
Pressure Distributions ◽  
Air Volume ◽  
Computational Fluid Dynamics Cfd ◽  
Traditional Construction ◽  
Ventilation Scheme

For the purpose of avoiding the deficiency of the traditional construction ventilation, the ventilation of the underground main powerhouse is simulated by the computational fluid dynamics (CFD) to optimize ventilation parameters. A 3D unsteady RNG k-ε model is performed for construction ventilation in the underground main powerhouse. The air-flow field and CO diffusion in the main powerhouse are simulated and analyzed. The two construction ventilation schemes are modelled for the main powerhouse. The optimized ventilation scheme is obtained by comparing the air volume and pressure distributions of the different ventilation schemes.

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