The morphological and mineralogical characteristics and thermal conductivity of ash deposits in a 220 MW CFBB firing Zhundong lignite

Long, Xiaofei; Li, Jianbo; Wang, Hongjian; Liang, Yintang; Lu, Xiaofeng; Zhang, Dongke

doi:10.1016/j.energy.2022.125842

Cited by 5 publications

(5 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In industrial practice, with an even higher thickness of 6.0-8.0 mm, the maximum temperature of the tube surface could be increased. Moreover, in order to maintain the rated output in industrial boilers, more fuel and a higher flue gas temperature are required [7]. These would inevitably raise the risks of tube explosions as a result of overheating.…”

Section: Discussionmentioning

confidence: 99%

“…In Equation (7), the first and second terms represent the deposition of sticky particles on the surface and the deposition of non-sticky particles on the sticky surface, respectively. p p (T p ) and p s (T s ) are the sticking probability of the particles and the deposition surface, which can be calculated using the critical viscosity formula Equation [8,13,35,36].…”

Section: Deposition Modelmentioning

confidence: 99%

“…On the j mesh surface in a time step, ∆δ j is the growth height, ∆m j is the deposition mass, A j is the mesh area, ρ p is the particle density and ε is the porosity, which is taken as 0.5 [18]. In order to prevent the phenomenon of "negative grid" between adjacent meshes, the growth height is homogenized, as shown in Equation (7), and the weighted average is applied to ∆δ j .…”

Section: Dynamic Meshmentioning

confidence: 99%

“…As a consequence, unplanned plant shutdowns have been incurred in certain cases, not to mention the thermal and economic deficiency during operation and maintenance [3][4][5]. For instance, severe ash deposition on superheaters and re-heaters has been reported during thermal utilization of Zhundong lignite [6,7]. Nonetheless, insights into the dynamic deposition process, including detailed mathematical descriptions and evaluations of the ash transportation process, are still insufficient [8].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Numerical Simulation Study into the Effect of Longitudinal and Transverse Pitch on Deposition of Zhundong Coal Ash on Tube Bundles

Guo,

Li,

Liang

et al. 2024

Processes

Self Cite

View full text Add to dashboard Cite

In this paper, the dynamic deposition behavior of Na-enriching Zhundong coal ash on tube bundles with varying longitudinal and transverse pitches was numerically studied. By using a modified critical viscosity model, an improved CFD deposition model has been established and key parameters, including deposit mass and morphology, particle trajectories and impaction and sticking probabilities, as well as the heat flux distribution, have been analyzed. The results show that the ash deposited on tubes in the first row is, respectively, 1.74 and 3.80 times higher than that on the second and third rows, proving that ash deposition in the downstream is lessened. As the longitudinal pitch increased from 1.50 D to 2.50 D, deposit mass in the downstream increased two times, suggesting that an increase in longitudinal pitch would aggravate ash deposition. The effect of transverse pitch, however, with the least deposit propensity at St/D = 1.75, is non-linear due to the joint effect of adjacent tubes and walls in affecting particle trajectory. In addition, due to the non-uniform distribution of the deposit, heat flux across the tube is the smallest at the stagnation point but becomes six times higher at two sides and the leeward, which makes the thermal damage of these sides to be warranted as a practical concern.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Deposition Modelmentioning

confidence: 99%

Section: Dynamic Meshmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Numerical Simulation Study into the Effect of Longitudinal and Transverse Pitch on Deposition of Zhundong Coal Ash on Tube Bundles

Guo,

Li,

Liang

et al. 2024

Processes

Self Cite

View full text Add to dashboard Cite

show abstract

“…13 Hence, the need to enhance its thermal conductivity is crucial. The prevalent approach involves incorporating high thermal conductivity particles, such as Al2O3, 14 Cu, 15 MWCNTs, 16 and graphene, 17 among others, into the PCM. For instance, Mani et al 18 effectively increased the thermal conductivity of pentaerythritol by 22.5% through the use of copper nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Oriented High Thermal Conductivity Solid–Solid Phase Change Materials for Mid-Temperature Solar-Thermal Energy Storage

Dai

Gao

Wang

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

As the global energy crisis intensifies, the development of solar energy has become a vital area of focus for many nations. The utilization of phase change materials (PCMs) for photothermal energy storage in the medium temperature range holds great potential for various applications, but their conventional forms face several challenges. For instance, the longitudinal thermal conductivity of photothermal PCMs is inadequate for effective heat storage on the photothermal conversion surface, and there is a risk of leakage due to repeated solid–liquid phase transitions. Here, we report a solid–solid phase change material, tris(hydroxymethyl)aminomethane (TRIS), which has a phase change temperature of 132 °C in the medium temperature range, enabling high-grade and stable solar energy storage. To overcome the low thermal conductivity problem, we propose a large-scale production of oriented high thermal conductivity composites by compressing a mixture of TRIS and expanded graphite (EG) using the pressure induction method to create in-plane highly thermally conductive channels. Remarkably, the resulting phase change composites (PCCs) exhibit a directional thermal conductivity of 21.3 W/(m·K). Furthermore, the high phase change temperature (132 °C) and large phase change entropy (213.47 J/g) enable a large-capacity high-grade thermal energy to be used. The developed PCCs, when combined with selected photo-absorbers, exhibit efficient integration of solar-thermal conversion and storage. Additionally, we also demonstrated a solar-thermoelectric generator device with an energy output of 93.1 W/m2, which is close to the power of photovoltaic systems. Overall, this work provides a technological route to the large-scale fabrication of mid-temperature solar energy storage materials with high thermal conductivity, high phase change enthalpy, and no risk of leakage, and also offers a potential alternative to photovoltaic technology.

show abstract

Investigation into the fusibility of biomass ashes and their mineral phase transformations at elevated temperatures by using the HT-XRD technique

Long

Zhu³

et al. 2023

Biomass and Bioenergy

View full text Add to dashboard Cite

The morphological and mineralogical characteristics and thermal conductivity of ash deposits in a 220 MW CFBB firing Zhundong lignite

Cited by 5 publications

References 32 publications

A Numerical Simulation Study into the Effect of Longitudinal and Transverse Pitch on Deposition of Zhundong Coal Ash on Tube Bundles

A Numerical Simulation Study into the Effect of Longitudinal and Transverse Pitch on Deposition of Zhundong Coal Ash on Tube Bundles

Oriented High Thermal Conductivity Solid–Solid Phase Change Materials for Mid-Temperature Solar-Thermal Energy Storage

Investigation into the fusibility of biomass ashes and their mineral phase transformations at elevated temperatures by using the HT-XRD technique

Contact Info

Product

Resources

About