Simulation Study of Shenmu Coal Pyrolysis by Gas Heat Carrier Based on a Moving Bed

Liang, Peng; Zhang, Yaqing; Jiang, Wenjing; Wei, Aifang; Liu, Tao; Wu, Jiafeng

doi:10.1021/acs.energyfuels.5b01821

Cited by 25 publications

(12 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Moreover, it should be mentioned that the convective heat flux is very sensitive to the relative velocity of the gas-solid phase (|u CG −u coal |). Thus, a moving-bed 19 or a fixed-bed reactor with specific internals 43 that enhance the interparticle mass transfer is suggested for lignite pyrolysis with SHCs to obtain high heating rates. Figure 5 shows the temperature history (a) and transient weight loss fraction of coal (b) along the radial direction within a lignite particle for the base conditions.…”

Section: Numerical Methods For Solving the Modelmentioning

confidence: 99%

A model of devolatilization behavior in lignite pyrolysis with solid heat carriers

Feng

et al. 2019

AIChE Journal

View full text Add to dashboard Cite

To elucidate the influence of the process conditions on pyrolytic products, the interactions between transport phenomena and pyrolysis kinetics are quantitatively analyzed at the level of a single coal particle. A comprehensive mathematical model is formulated to predict intraparticle multiphysics and devolatilization behaviors; the model contains two correlative one-dimensional unsteady heat conservation equations and ternary mass conservation equations in conjunction with the simplified dusty-gas model. Moreover, a multistep kinetic model of coal devolatilization is adopted to predict the generating rates of the lumped pyrolytic products. Validation of the model against experimental and literature data showed that can predict the transient temperature profiles of a coal particle and the yields of volatiles. Finally, the effects of the main process conditions on the intra-and extra-temperature history of lignite during pyrolysis with solid heat carriers are analyzed. The interactions between physical transport and the pyrolysis reaction are also examined. K E Y W O R D S devolatilization, heat transfer and mass transfer, lignite pyrolysis, numerical simulation, solid heat carrier 1 | INTRODUCTION Recently, the rapid consumption of high-quality coal resources has promoted innovative technologies for effective and efficient utilization of low-rank coal, that is, lignite, which has become a significant gateway to relieve ever-growing energy demands. To the best of our knowledge, lignite deposits are relatively abundant and have the advantage of low-cost mining; however, extensive application of lignite is stunted by its low degree of coalification, involving high moisture and ash content but relatively low energy density. To overcome these drawbacks, various upgrading technologies, including drying, dewatering, and pyrolysis, have been developed to improve lignite quality in terms of calorific value, heat stability, and moisture absorption. Among these techniques, pyrolysis with heat carriers at moderate temperatures is superior because it makes full use of the characteristics of lignite, such as its enriched volatile content and positive reactive behavior. Compared to the external heating mode, in which heat is input from the inner wall of a pyrolyzer, solid heat carriers (SHCs) as direct heat sources used in an internal heating system can greatly increase the effective heat transfer area, which weakens the bed axial temperature gradients and eliminates local overheating. In this way, the severe problem for tar species depositing or cracking on the inner walls of pyrolyzer is suppressed, although the effective separation between the tar and semi-coke powders remains to be solved. In addition, high value-added components are heavily concentrated in tar, such as aliphatic hydrocarbon, aromatic hydrocarbon, and phenols, since the oxygen-containing functional groups in lignite are well retained during pyrolysis, which leads to improved economic performance after hydrofining. Currently, coal pyrolysis with SHCs in a pi...

show abstract

Section: Numerical Methods For Solving the Modelmentioning

confidence: 99%

A model of devolatilization behavior in lignite pyrolysis with solid heat carriers

Feng

et al. 2019

AIChE Journal

View full text Add to dashboard Cite

show abstract

“…134 To this goal, different heat carriers have been considered as mediums, which enhance the heat transfer rate and the process efficiency. 135 In this way, sands, 135,136 gaseous compounds like nitrogen, 137 etc. have been considered as heating media.…”

Section: Introductionmentioning

confidence: 99%

Moving Bed Reactors: Challenges and Progress of Experimental and Theoretical Studies in a Century of Research

Shirzad

Karimi

Silva

et al. 2019

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Moving bed reactors (MBRs) have been proposed as a sign of significant progress in the reaction engineering area for performance improving and energy saving. Since their advent in 1890, the MBRs have attracted a wide acceptance in different industries, while they were first developed for the drying industries. The progress that this technology has made during its evolution led to the introduction of these reactors as a pioneer strategy in other industries including petroleum, petrochemical, pyrolysis, and biomass industries. In the traditional reaction systems, the process performance decreases during the operational conditions, while MBRs have obviated this drawback by having an all-around permanent acceptable efficiency. In this context, the present work provides an overview on the evolution of MBRs by investigating the main experimental and theoretical studies. In this way, the experimental studies have typically taken into account operational conditions and production rates of different products, while in the theoretical research, modeling, and simulation of conventional processes, the evaluation of novel configurations and the optimization techniques have been investigated. In the end, some suggestions are proposed to modify the traditional MBRs as helpful ideas for further studies.

show abstract

“…O leito móvel é particularmente valioso devido a sua condição estável de operação, aquecimento uniforme e ampla faixa de mudança no tempo de contato gás-sólido (LIANG, P. et al 2015), sendo uma técnica de aquecimento ou resfriamento de uma mistura de sólidos granulares e fluido em escoamento concorrente ou contracorrente (BERTOLI, 2000). A compreensão do escoamento multifásico e do comportamento térmico nestes reatores é importante para o projeto e otimização de processos (Yang, et al, 2015).…”

Section: Introductionunclassified

Solução Autoadjunta De Um Modelo De Transferência De Calor Em Leito Móvel Com Aquecimento Na Parede Por Gás De Combustão E Transferência De Calor Radiante Indireta

Krummenauer¹,

Wernke²,

Ender³

et al. 2018

Blucher Chemical Engineering Proceedings

View full text Add to dashboard Cite

RESUMO -Apresenta-se um modelo para a transferência de calor em leito móvel tubular e escoamento concorrente, incluindo efeitos de radiação térmica, com sólidos constituídos por esferas de raio uniforme, transportadas pneumaticamente pelo fluido de arraste em escoamento pistonado. A parede do reator é envolvida externamente por uma jaqueta, a qual é aquecida pelo gás de combustão que flui em região anular concêntrica. A transferência de calor radiante (indireta) entre as partículas e o gás de combustão é incluída no modelo de forma aproximada. A solução analítica é desenvolvida pelo Método dos Operadores Autoadjuntos (MOA). Os resultados são comparados com solução numérica obtida através de método híbrido: Método Analítico Finito (MAF) e Método de Diferenças Finitas (MDF) demonstrando concordância e assim, o potencial da solução analítica desenvolvida na verificação de soluções numéricas.

show abstract

Simulation Study of Shenmu Coal Pyrolysis by Gas Heat Carrier Based on a Moving Bed

Cited by 25 publications

References 24 publications

A model of devolatilization behavior in lignite pyrolysis with solid heat carriers

A model of devolatilization behavior in lignite pyrolysis with solid heat carriers

Moving Bed Reactors: Challenges and Progress of Experimental and Theoretical Studies in a Century of Research

Solução Autoadjunta De Um Modelo De Transferência De Calor Em Leito Móvel Com Aquecimento Na Parede Por Gás De Combustão E Transferência De Calor Radiante Indireta

Contact Info

Product

Resources

About