Development of Biomass Gasification Technology with Fluidized-Bed Reactors for Enhancing Hydrogen Generation: Part I, Hydrodynamic Characterization of Dual Fluidized-Bed Gasifiers

Chyou, Yau-Pin; Chang, Der-Ming; Chen, Po-Chuang; Chien, Hsiu-yun; Wu, Keng-Tung; Chein, Reiyu

doi:10.3390/app10010002

Cited by 18 publications

(7 citation statements)

References 23 publications

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“…The conversion of methanol to olefins (MTO) over acidic zeolites is an effective alternative way to cracking of naphtha to light olefins, as methanol can be expediently produced via synthesis gas from multifarious carbon sources such as coal, natural gas, and biomass. − In the past decades, a great deal of effort has been devoted to the elucidation of MTO mechanisms on the basis of experimental and theoretical studies. − A consensus has been reached that the hydrocarbon pool (HCP) mechanism, including aromatic-based and alkene-based cycles, dominates the reaction process at the steady period. In the aromatic-based cycle, polymethylbenzenes (polyMBs) trapped in zeolite pores are considered as active HCP species, whereas the alkene-based cycle is based on the successive methylation and cracking reactions of C 3 + alkenes .…”

Section: Introductionmentioning

confidence: 99%

Unraveling the Relationship between Zeolite Structure and MTO Product Distribution by Theoretical Study of the Reaction Mechanism

et al. 2021

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Determination of the relative contributions of aromatic-based and alkene-based cycles in the MTO process is essential for understanding the reaction mechanism and estimating the product selectivity over various zeolites. However, it is a great challenge due to the high complexity of the reaction network. Thus, the olefin formation mechanisms are systematically investigated here by the density functional theory with van der Waals dispersive corrections over structurally different zeolites. It is shown that the aromatic-based cycle dominates the MTO process over H-SAPO-34 with a side-chain route as the major reaction pathway, while the alkene-based cycle plays a major role on H-BEA and H-ZSM-5. Over H-ZSM-22, the alkene-based cycle is the main route with C 5 + alkenes as primary products. The energy barriers of the aromatic-based cycle are similar over the above four types of zeolites. A linear relationship is found between the ethene/propene molar ratios and the free energy barriers of alkene-based cycles over these zeolites, indicating that the ethene and propene selectivities are mainly determined by the propagation of the alkene-based cycle. This suggests that the ultimate free energy barrier of the alkene-based cycle can be used as a measure to predict the C 2 = /C 3 = molar ratios obtained on topologically different zeolites.

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Section: Introductionmentioning

confidence: 99%

Unraveling the Relationship between Zeolite Structure and MTO Product Distribution by Theoretical Study of the Reaction Mechanism

et al. 2021

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“…9 Various experiments and parametric studies were performed in the CFMs of different DFBG configurations to study the syngas characteristics and the hydrodynamic behaviors under different conditions. 20 Kaiser et al 21 studied the stability of operation, the pressure profile, and the SCR in a lab-scale DFB cold flow system. The effects of the solids inventory and the configuration of gasifier-riser connection on the system hydrodynamics were also investigated.…”

Section: Introductionmentioning

confidence: 99%

“…Besides predicting hydrodynamic parameters at different operating conditions of the system, CFMs further support investigating the thermo‐chemical processes in the hot models based on their outcomes 9 . Various experiments and parametric studies were performed in the CFMs of different DFBG configurations to study the syngas characteristics and the hydrodynamic behaviors under different conditions 20 . Kaiser et al 21 studied the stability of operation, the pressure profile, and the SCR in a lab‐scale DFB cold flow system.…”

Section: Introductionmentioning

confidence: 99%

Effect of sand particle size on the hydrodynamics of a dual fluidized bed cold flow system applied for waste‐to‐energy gasifiers

Dinh

Hsiau

et al. 2022

Intl J of Energy Research

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Summary Since the dual fluidized bed (DFB) system has been increasingly adopted for waste‐to‐energy gasification, a three‐dimensional computational fluid dynamics full‐loop model of a DFB cold flow system has been developed to predict the pressure and sand circulation rate (SCR) under various operating conditions. The pressure data were recorded at 18 specified points along the system height. In addition, the SCRs were determined at the two crucial positions connecting the riser and the gasifier and vice versa. The simulation results were then validated against the experimental data, taking into account the effects of the sand particle size (ds), the air inlet velocity in the riser (v0,riser), and the initial gasifier bed height (h0,gasifier). It could be observed in the riser that the flow structures of the smaller ds(s) were almost scattering patterns, while those of the bigger ones were mainly clusters. Compared with bigger ds(s), more homogeneous pressure distributions in the riser and higher bed expansion in the gasifier were obtained with smaller ones. A compromise between the system performance and pre‐treating cost for the feedstock particle sizes should be considered further to achieve the best system performance. On the other hand, the increases of the v0,riser and the h0,gasifier enhanced the gasifier bed pressure, facilitating the downward sand flow back to the riser via the LLS. Although some minor discrepancies existed between the simulation and experimental data, the predicted tendencies agreed well with the measured ones. It was also found that a system operating with ds = 500 μm, at v0,riser = 4.0 m/s and h0,gasifier = 0.25 m yielded stable flow characteristics and optimal global SCR. Moreover, some unexpected phenomena predicted and verified with the experimental observations could be avoided or minimized using suitable particle sizes of the feedstock and operating parameters. In sum, the better validation results with lower errors than our previous study, the more reasonable air‐sand flow patterns, and the substantial predictions of undesirable problems are the significant improvements of this study, providing valuable information for effectively designing and operating the practical DFB hot flow systems. Novelty Statement This study developed a 3D computational fluid dynamics full‐loop model of a DFB cold flow system for predicting the pressure and sand circulation rates under various operating conditions of particle size, inlet velocity, and initial bed height. The better validation results against the experimental data, the more reasonable air‐sand flow patterns, and the substantial predictions of undesirable problems are the significant improvements of this study, providing helpful information for designing and operating the DFB hot flow gasifiers.

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“…This is connected with several factors that have been discussed in many studies (e.g., References [1][2][3]). At the same time, one of the most remarkable trends of recent years is the investigation of different ways of producing energy from waste and biomass [4,5]. This field is developing rapidly since current rates of production and consumption result in large amounts of products suitable for secondary energy generation [6,7].…”

Section: Introductionmentioning

confidence: 99%

Multi-Criteria Efficiency Analysis of Using Waste-Based Fuel Mixtures in the Power Industries of China, Japan, and Russia

et al. 2020

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This paper presents the results of analyzing the efficiency of the following five fuel types: dry coal, wet coal processing waste, coal–water slurry, and two waste-derived slurries. In the calculations, we employed 16 criteria related to the energy industry, economy, social aspects, safety at plants, and environmental protection. We used the experimental data, obtained from the combustion of the fuels under study at three heating temperatures (700 °C, 800 °C, and 900 °C). Three countries were analyzed, where all of them have a high share of using fossil fuels in the energy industry: Japan, China, and Russia. The total performance indicator was calculated using three multiple-criteria decision analysis techniques (weighted sum method, weighted product method, and analytic hierarchy process). The choice of weight coefficients was confirmed for each method. We found that coal and coal–water slurry had the lowest integral efficiency indicators (0.016–0.535 and 0.045–0.566, respectively). The maximum effect was achieved when using waste-derived slurry with used turbine oil (0.190–0.800) and coal processing waste (0.535–0.907). There were, on average, 3%–60% differences in the integral efficiency indicator for the same fuel in different countries. The difference in the efficiency indicator of the same fuel in different countries was on average 3%–60%; with changes in temperature, the difference in efficiency was 5%–20%; and when changing the calculation procedure, the difference was 10%–90%.

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Development of Biomass Gasification Technology with Fluidized-Bed Reactors for Enhancing Hydrogen Generation: Part I, Hydrodynamic Characterization of Dual Fluidized-Bed Gasifiers

Cited by 18 publications

References 23 publications

Unraveling the Relationship between Zeolite Structure and MTO Product Distribution by Theoretical Study of the Reaction Mechanism

Unraveling the Relationship between Zeolite Structure and MTO Product Distribution by Theoretical Study of the Reaction Mechanism

Effect of sand particle size on the hydrodynamics of a dual fluidized bed cold flow system applied for waste‐to‐energy gasifiers

Multi-Criteria Efficiency Analysis of Using Waste-Based Fuel Mixtures in the Power Industries of China, Japan, and Russia

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