Validation and application of CPFD model in simulating gas-solid flow and combustion of a supercritical CFB boiler with improved inlet boundary conditions

Yan, Jin; Lu, Xiaofeng; Xue, Rui; Lu, Junhui; Zheng, Yue; Zhang, Yi; Liu, Zhuo

doi:10.1016/j.fuproc.2020.106512

Cited by 26 publications

(10 citation statements)

References 42 publications

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“…There are three furnace outlets at one side of the 600 MW CFB boiler, and each outlet corresponds to two returning ports. The flow rate of each circulation loop was determined by our previous experimental and calculated results [17]. Simulations in this study were performed with Ansys FLUENT.…”

Section: Computational Mesh and Solution Methodsmentioning

confidence: 99%

“…In particular, the standard deviations of the lateral diffusion distance of the IUSA and ILSA increased nearly three times under the non-uniform SA condition. The reason is that the solid concentration on the inclined wall of the pent-leg furnace is higher than that on the outer wall [17], so changes of SA velocity distribution have a greater impact on the gas lateral diffusion.…”

Section: Influence Of Sa Uniformity On Jet Penetration and Diffusionmentioning

confidence: 99%

“…In large-scale utility CFB boilers, this effect cannot be ignored. Therefore, based on our previous work related to SA [16,17], this paper took the first 600 MW supercritical CFB boiler as a research object and carried out a numerical simulation based on the actual SA velocity distributions. The influence of SA distribution uniformity, load variation on SA jet penetration and diffusion, and changes of gas-solid flow in the furnace were analyzed in detail.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study of the Influence of Secondary Air Uniformity on Jet Penetration and Gas-Solid Diffusion Characteristics in a Large-Scale CFB Boiler

et al. 2021

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The uniformity of secondary air (SA) in large-scale CFB boilers has an important influence on gas-solid flow and combustion, but was seldom considered in previous studies. Numerical simulation based on the Eulerian–Eulerian and RNG k-ε turbulence models was conducted to explore the influence of SA uniformity and load variation on jet penetration, diffusion characteristics and gas-solid mixing in the first 600 MW supercritical CFB boiler. The results showed that better SA uniformity was conductive to the uniformity of SA penetration and gas-solid mixing along the furnace height, although the penetration depth and diffusion distance showed an opposite trend. In addition, the penetration depth and diffusion distance got enhanced with higher boiler load. The inner and outer SA jets could not cover the furnace width, and the uneven SA uniformity led to a huge deviation of the solid concentration within 10 m of the air distributor. Eventually, a calculation model was successfully established for predicting the penetration depth of inclined thermal SA jets during boiler operation.

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Section: Computational Mesh and Solution Methodsmentioning

confidence: 99%

Section: Influence Of Sa Uniformity On Jet Penetration and Diffusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical Study of the Influence of Secondary Air Uniformity on Jet Penetration and Gas-Solid Diffusion Characteristics in a Large-Scale CFB Boiler

et al. 2021

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“…The Ecom-J2KN type analyzer was for routine use, while the Testo 350 type analyzer would be used in the areas with odd values or large concentration gradients as a check. According to our experience of on-site tests, the gas composition would still show sinusoidal fluctuation under stable loads [32,33], so at least two groups of peak/valley values of flue gas should be recorded. As the height of the horizontal flue pass was 10 m and the ash deposition layer at the bottom was about 2-3 m, the maximum penetration depth of 7 m could basically cover the flow area of the SNCR inlets.…”

Section: Measurement Port Arrangement and Test Proceduresmentioning

confidence: 99%

An Experimental Study on the Characteristics of NOx Distributions at the SNCR Inlets of a Large-Scale CFB Boiler

Yan

Zhang

et al. 2021

Energies

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The unknown NOx distributions inside large-scale CFB (circulating fluidized bed) boilers have always hindered the economy of the SNCR (selective non-catalytic reduction) process. In this study, field tests were carried out on a typical 300 MW CFB boiler, where multi-level 316 L-made probe and Ecom-J2KN/Testo 350 analyzers were used to perform detailed two-dimensional distributions of flue gas composition at SNCR inlets for the first time. The penetration depth inside the horizontal flue pass was up to 7 m. The NOx distributions were analyzed in detail combining with the auxiliary test in the dilute phase zone. Key results show that the average O2 concentrations in #A and #C regions were 6.52% and 0.95%, respectively. The vertical NOx distributions of #A and #C SNCR inlets were similar, showing a trend of first increasing and then decreasing with peak value all appeared at 5 m depth, while the NOx distribution of #B SNCR inlet was basically increasing. Some local areas with extremely high NOx concentration (over 2000 mg/m3) were observed near the inclined edge of SNCR inlets, which has never been reported before. Based on this, the optimization of urea injections was conducted, which could save 15.7% of the urea solution consumption while ensuring ultra-low emission of NOx.

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“…The CFD models can be used for complex analysis of multi-fuel CFB (circulating fluidized bed) unit operation concepts [ 6 , 7 , 8 , 9 ]. Various 3D-CFB models can be found in the literature [ 10 , 11 , 12 , 13 , 14 , 15 ], some of which consider the multi-fuel, CFB concept; however, the use of gaseous fuel, with a properly organized gas supply system, cannot be found in said literature. Such an idea may be beneficial for a power unit’s flexibility and provides the stable operation of a boiler furnace with a substantial demand reduction in its capacity.…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive, Three-Dimensional Analysis of a Large-Scale, Multi-Fuel, CFB Boiler Burning Coal and Syngas. Part 2. Numerical Simulations of Coal and Syngas Co-Combustion

Krzywański

Sztekler

Szubel

et al. 2020

Entropy

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This paper presents the results of numerical computations for a large-scale OFz-425 CFB (circulating fluidized bed) boiler utilizing coal and syngas. Four different operating scenarios are considered, including the reference variant, corresponding to the conventional, mono-combustion of bituminous coal, and three tests involving replacement of secondary air and part of the coal stream with syngas fed by start-up burners. Pressure, gas velocity, temperature, and carbon dioxide distribution in the combustion chamber are discussed in the paper. The results indicate that the syngas supply leads to an increase in local temperature and carbon dioxide concentrations. The proposed concept is not advisable as it may lead to frequent emergency stops of the CFB boiler.

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Validation and application of CPFD model in simulating gas-solid flow and combustion of a supercritical CFB boiler with improved inlet boundary conditions

Cited by 26 publications

References 42 publications

Numerical Study of the Influence of Secondary Air Uniformity on Jet Penetration and Gas-Solid Diffusion Characteristics in a Large-Scale CFB Boiler

Numerical Study of the Influence of Secondary Air Uniformity on Jet Penetration and Gas-Solid Diffusion Characteristics in a Large-Scale CFB Boiler

An Experimental Study on the Characteristics of NOx Distributions at the SNCR Inlets of a Large-Scale CFB Boiler

A Comprehensive, Three-Dimensional Analysis of a Large-Scale, Multi-Fuel, CFB Boiler Burning Coal and Syngas. Part 2. Numerical Simulations of Coal and Syngas Co-Combustion

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