Comparative scaling analysis of two different sized pilot-scale fluidized bed reactors operating with biomass substrates

This paper presents a comprehensive study results on scale-up and biomass hold-up characteristics of biological fluidized bed reactors (BFBR). The overall objective of this study was to establish and test some basic design criteria for the scaling-up or scaling-down of anaerobic fluidized bed reactors. A 12.5 1 laboratory-scale fluidized bed was designed and constructed based on a geometrically similar 70 1 pilot scale fluidized bed and the process performances were compared. Biomass hold up characteristics of the BFBRs were also investigated during the experimental studies. A general expression was developed for predicting the biological fludized bed porosities. Using this expression, both the local and overall fluidized bed porosities could be predicted depending on biofilm thickness, expansion coefficient, media diameter and density. The validity of this expression was tested with the data from this study.

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Coarse-Grain DEM Modelling in Fluidized Bed Simulation: A Review

Processes ◽

10.3390/pr9020279 ◽

2021 ◽

Vol 9 (2) ◽

pp. 279

Author(s):

Alberto Di Renzo ◽

Erasmo Napolitano ◽

Francesco Di Maio

Keyword(s):

Fluidized Bed ◽

Fluidized Beds ◽

Circulating Fluidized Bed ◽

Coarse Graining ◽

Pilot Scale ◽

Contact Forces ◽

Coarse Grain ◽

Fluidized Bed Reactors ◽

Future Directions ◽

Spouted Beds

In the last decade, a few of the early attempts to bring CFD-DEM of fluidized beds beyond the limits of small, lab-scale units to larger scale systems have become popular. The simulation capabilities of the Discrete Element Method in multiphase flow and fluidized beds have largely benefitted by the improvements offered by coarse graining approaches. In fact, the number of real particles that can be simulated increases to the point that pilot-scale and some industrially relevant systems become approachable. Methodologically, coarse graining procedures have been introduced by various groups, resting on different physical backgrounds. The present review collects the most relevant contributions, critically proposing them within a unique, consistent framework for the derivations and nomenclature. Scaling for the contact forces, with the linear and Hertz-based approaches, for the hydrodynamic and cohesive forces is illustrated and discussed. The orders of magnitude computational savings are quantified as a function of the coarse graining degree. An overview of the recent applications in bubbling, spouted beds and circulating fluidized bed reactors is presented. Finally, new scaling, recent extensions and promising future directions are discussed in perspective. In addition to providing a compact compendium of the essential aspects, the review aims at stimulating further efforts in this promising field.

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Novel Synthesis of Silicon/Carbon Nanotubes Microspheres as Anode Additives Through Chemical Vapor Deposition in Fluidized Bed Reactors

SSRN Electronic Journal ◽

10.2139/ssrn.3659826 ◽

2020 ◽

Author(s):

Hong Zhao ◽

Ning TU ◽

Weibin Zhang ◽

Min Zhang ◽

Jian Wang

Keyword(s):

Carbon Nanotubes ◽

Chemical Vapor Deposition ◽

Fluidized Bed ◽

Vapor Deposition ◽

Chemical Vapor ◽

Fluidized Bed Reactors ◽

Novel Synthesis ◽

Silicon Carbon

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Influence of Seeding Conditions on Initial Biofilm Development during the Startup of Anaerobic Fluidized Bed Reactors

Water Science & Technology ◽

10.2166/wst.1989.0219 ◽

1989 ◽

Vol 21 (4-5) ◽

pp. 157-165 ◽

Cited By ~ 2

Author(s):

F. Ehlinger ◽

J. M. Audic ◽

G. M. Faup

Keyword(s):

Fluidized Bed ◽

Future Development ◽

Protein Concentration ◽

Specific Activity ◽

Fluidized Bed Reactor ◽

Fluidized Bed Reactors ◽

Support Material ◽

Biofilm Development ◽

Initial Biofilm

The characterization of the biofilm of an anaerobic fluidized-bed reactor was completed under standard conditions. The distribution of the fixed protein concentration depended on the level in the reactor. The protein concentration reached 1520 µg.g−1 of support at the top of the reactor and only 1200 µg.g−1 at the bottom after 504 hours of operation but the specific activity of the biofilm was 33×10−4 µM acetate.h−1.mg−1 proteins at the bottom and only 26×10−4 µM.h−1.mg−1 at the top. The efficiency of a fluidized bed reactor and the composition of the biofilm changed with an increase of the pH from 7 to 8.5 during the seeding of the support material. Future development of the biofilm and the specific activity of the support were affected.

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Anaerobic/aerobic biodegradation of pentachlorophenol using GAC fluidized bed reactors: optimization of the empty bed contact time

Water Science & Technology ◽

10.2166/wst.1997.0581 ◽

1997 ◽

Vol 36 (6-7) ◽

pp. 107-115 ◽

Cited By ~ 4

Author(s):

Gregory J. Wilson ◽

Amid P. Khodadoust ◽

Makram T. Suidan ◽

Richard C. Brenner

Keyword(s):

Fluidized Bed ◽

Oxygen Demand ◽

Aerobic Biodegradation ◽

Fluidized Bed Reactors ◽

Reactor Performance ◽

Reactor Operation ◽

Significant Cost ◽

Second Stage ◽

Primary Substrate ◽

Chlorinated Phenolic Compounds

An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to predominately equimolar concentrations (>99%) of monochlorophenol (MCP) in two GAC fluidized bed reactors at Empty Bed Contact Times (EBCTs) ranging from 18.6 to 1.15 hours. However, at lower EBCTs, MCP concentrations decreased to less than 10% of the influent PCP concentration suggesting mineralization. The optimal EBCT was determined to be 2.3 hours based on PCP conversion to MCPs and stable reactor operation. Decreasing the EBCT fourfold did not inhibit degradation of PCP and its intermediates, thus allowing removal of PCP at much lower detention time and resulting in a significant cost advantage. Analytical grade PCP was fed via syringe pumps into two fluidized bed reactors at influent concentrations of 100 mg/l and 200 mg/l, respectively. Acting as the primary substrate, ethanol was also fed into the reactors at concentrations of 697 and 1388 mg/l. Effluent PCP and chlorinated phenolic compounds were analyzed weekly to evaluate reactor performance. Biodegradation pathways were also identified. 3-chlorophenol (CP) was the predominant MCP and varied simultaneously with 3,5-dichlorophenol (DCP) concentrations. Likewise, 4-CP concentrations varied simultaneously with 3,4-DCP concentrations. A second stage aerobic GAC fluidized bed reactor was added after the anaerobic reactor to completely mineralize the remaining MCP and phenols. Data show no presence of phenol and MCP in the effluent or on the GAC. Overall, the chemical oxygen demand (COD) fed to the system was reduced from 75 g/d in the influent to less than 1.5 g/d in the effluent.

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Aromatic Transformation in Fluidized Bed Reactors

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20081061 ◽

2008 ◽

Vol 73 (8-9) ◽

pp. 1061-1088

Author(s):

Sule Rabiu ◽

Sulaiman Al-Khattaf

Keyword(s):

Fluidized Bed ◽

The Other ◽

Fluidized Bed Reactors ◽

Y Zeolite ◽

Y Zeolites ◽

Toluene Disproportionation ◽

Xylene Isomerization ◽

Toluene Methylation ◽

Toluene Conversion ◽

Medium Acidity

In this work three important aromatic transformations, namely: toluene disproportionation, toluene methylation and m-xylene isomerization, were investigated in a riser simulator which closely mimics the operation of commercial fluidized bed reactors. The transformations were studied over a ZSM-5 based catalyst with medium acidity of 0.23 mmol/g and a series of Y zeolites of acidities between 0.55 and 0.03 mmol/g. For pure toluene feed, it was observed that conversion over the ZSM-5 based catalyst and the weakly acidic Y zeolite (USY-1) was very low. However, with the highly acidic Y zeolite (H-Y), significant toluene conversion was observed with paring reaction more prominent than disproportionation. On the other hand, when toluene was alkylated with methanol, higher toluene conversions were achieved over both the ZSM-5 based and the weakly acidic USY-1 catalysts as compared to when pure toluene feed was used. In addition, p-xylene/o-xylene (P/O) ratios higher than the equilibrium values were obtained in the reaction product over both catalysts. Finally, for m-xylene isomerization it was found that m-xylene conversion increased initially as the acidity of the catalyst increased up to 0.1 mmol/g beyond which any further increase in acidity resulted in a slight decrease in the m-xylene conversion.

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Optimal polymer grade transitions for fluidized bed reactors

Journal of Process Control ◽

10.1016/j.jprocont.2020.02.001 ◽

2020 ◽

Vol 88 ◽

pp. 86-100 ◽

Cited By ~ 1

Author(s):

Yajun Wang ◽

Lorenz T. Biegler ◽

George S. Ostace ◽

Rita A. Majewski

Keyword(s):

Fluidized Bed ◽

Fluidized Bed Reactors

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Hydrogen Production by Fluidized Bed Reactors: A Quantitative Perspective Using the Supervised Machine Learning Approach

J ◽

10.3390/j4030022 ◽

2021 ◽

Vol 4 (3) ◽

pp. 266-287

Author(s):

Zheng Lian ◽

Yixiao Wang ◽

Xiyue Zhang ◽

Abubakar Yusuf ◽

Lord Famiyeh ◽

...

Keyword(s):

Machine Learning ◽

Hydrogen Production ◽

Fluidized Bed ◽

Biomass Gasification ◽

Supervised Machine Learning ◽

Fluidized Bed Reactors ◽

Hydrogen Yield ◽

Carbon Conversion ◽

Operational Parameters ◽

Operational Conditions

The current hydrogen generation technologies, especially biomass gasification using fluidized bed reactors (FBRs), were rigorously reviewed. There are involute operational parameters in a fluidized bed gasifier that determine the anticipated outcomes for hydrogen production purposes. However, limited reviews are present that link these parametric conditions with the corresponding performances based on experimental data collection. Using the constructed artificial neural networks (ANNs) as the supervised machine learning algorithm for data training, the operational parameters from 52 literature reports were utilized to perform both the qualitative and quantitative assessments of the performance, such as the hydrogen yield (HY), hydrogen content (HC) and carbon conversion efficiency (CCE). Seven types of operational parameters, including the steam-to-biomass ratio (SBR), equivalent ratio (ER), temperature, particle size of the feedstock, residence time, lower heating value (LHV) and carbon content (CC), were closely investigated. Six binary parameters have been identified to be statistically significant to the performance parameters (hydrogen yield (HY)), hydrogen content (HC) and carbon conversion efficiency (CCE)) by analysis of variance (ANOVA). The optimal operational conditions derived from the machine leaning were recommended according to the needs of the outcomes. This review may provide helpful insights for researchers to comprehensively consider the operational conditions in order to achieve high hydrogen production using fluidized bed reactors during biomass gasification.

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