A Study of High-Pressure CO2 Recycling Using Pinewood Char Gasification

2013 ◽  
Author(s):  
Indraneel Sircar ◽  
Anup Sane ◽  
Jay Gore
Keyword(s):  
Experimental Data ◽  
Mass Loss ◽  
Large Scale ◽  
High Pressures ◽  
Fixed Bed ◽  
High Sensitivity ◽  
Reaction Rates ◽  
Fixed Bed Reactor ◽  
Loss Data ◽  
High Pressure Co2

Measurements of the reaction rates at high-pressures for gasification of low-ash pinewood char with CO2 are presented. A fixed-bed reactor operated at 1140–1260 K and 1–10 atm was utilized in the present study. Product gas sampling and gas chromatograph measurements enabled tracking of the gasification progress and mass loss data. The mass loss data are interpreted using the volumetric and non-reactive core models. Activation energy, collision frequency and reaction order are reported for each model. The experimental data show high sensitivity to temperature. The data also show an increase of the apparent gasification rates with higher CO2 pressures. Comparison of computed char conversion profiles and experimental data are discussed in the context of mass transport and effects on the gasification rates. The findings from this study have applications to gasification modeling and design of large-scale gasification systems.

scholarly journals Pyrolysis Characteristics of Undervalued Wood Varieties in the Portuguese Charcoal Sector

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2537
Author(s):  
Felix Charvet ◽  
Felipe Silva ◽  
Luís Ruivo ◽  
Luís Tarelho ◽  
Arlindo Matos ◽  
...  
Keyword(s):  
Large Scale ◽  
Fixed Bed ◽  
Management Control ◽  
Fixed Bed Reactor ◽  
Fuel Load ◽  
Charcoal Production ◽  
Pyrolysis Characteristics ◽  
Major Market ◽  
Burnt Wood ◽  
Fuel Particles

Charcoal production in Portugal is mostly based on the valorization of woody residues from cork oak and holm oak, the latter being considered a reference feedstock in the market. Nevertheless, since wildfire prevention became a priority in Portugal, after the recent dramatic wildfires, urgent actions are being conducted to reduce the fuel load in the forests, which is increasing the amount of biomass that is available for valorization. Additionally, biomass residues from agriculture, forest management, control of invasive species, partially burnt wood from post-fire recovery actions, and waste wood from storm devastated forests need also to be considered within the national biomass valorization policies. This has motivated the present work on whether the carbonization process can be used to valorize alternative woody biomasses not currently used on a large scale. For this purpose, slow pyrolysis experiments were carried out with ten types of wood, using a fixed bed reactor allowing the controlled heating of large fuel particles at 0.1 to 5 °C/min and final temperatures within 300–450 °C. Apart from an evaluation of the mass balance of the process, emphasis was given to the properties of the resulting charcoals considering its major market in Portugal—barbecue charcoal for both recreational and professional purposes.

scholarly journals Conversion of Fructose to HMF in a Continuous Fixed Bed Reactor with Outstanding Selectivity

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1802 ◽  
Author(s):  
Eric Weingart ◽  
Sarah Tschirner ◽  
Linda Teevs ◽  
Ulf Prüße
Keyword(s):  
Large Scale ◽  
Continuous Process ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Water Addition ◽  
Batch Systems ◽  
Formation Conditions ◽  
High Yields ◽  
Optimized Conditions ◽  
By Products

5-Hydroxymethylfurfural (HMF) is a very promising component for bio-based plastics. Efficient synthesis of HMF from biomass is still challenging because of fast degradation of HMF to by-products under formation conditions. Therefore, different studies, conducted mainly in monophasic and biphasic batch systems with and without water addition have been published and are still under investigation. However, to produce HMF at a large scale, a continuous process is preferable. Until now, only a few studies have been published in this context. In this work, it is shown that fluorous alcohol hexafluoroisopropanol (HFIP) can act as superior reaction solvent for HMF synthesis from fructose in a fixed bed reactor. Very high yields of 76% HMF can be achieved in this system under optimized conditions, whilst the catalyst is very stable over several days. Such high yields are only described elsewhere with high boiling reaction solvents like dimethylsulfoxide (DMSO), whereas HFIP with a boiling point of 58 °C is very easy to separate from HMF.

Modeling of Low-Temperature Reduction of Metal Oxide in Hydrogen Treatment System for Severe Accidents in Nuclear Power Plants

2020 ◽  
Author(s):  
Kotaro Nakamura ◽  
Masashi Tanabe ◽  
Satoru Abe ◽  
Takashi Mawatari ◽  
Takao Nakagaki
Keyword(s):  
Water Vapor ◽  
Metal Oxide ◽  
Nuclear Power ◽  
Elevated Temperatures ◽  
Fixed Bed ◽  
Reaction Rates ◽  
Numerical Calculations ◽  
Treatment System ◽  
Fixed Bed Reactor ◽  
Hydrogen Treatment

Abstract At the Fukushima Daiichi nuclear power plant, zirconium in the fuel rod cladding reacted with water vapor at elevated temperatures due to a loss of cooling water, resulting in the production of a large amount of hydrogen. This hydrogen leaked from the reactor vessel and accumulated in the top of reactor building, eventually leading to an explosion. A hydrogen treatment system that re-oxidizes hydrogen to water vapor is one of the effective methods to prevent such an explosion. A prominent re-oxidation method is via a fixed bed reactor packed with metal oxide pellets. The advantages of this method are its relatively fast oxidation rate without external oxygen/air injection. In this study, experiments and complementary numerical calculations were performed on the hydrogen re-oxidation reaction by metal oxides. The oxidation of hydrogen by copper oxide is modeled by 5 interacting, elementary reactions consisting of 6 chemical species. Experiments were performed using two packed bed set-ups, with measurement of inlet/outlet gas composition and pre/post-analysis of solid composition used to determine constants of the individual reaction rates for numerical calculations. From these reaction constants, the temporal behavior of the outlet gas was predicted.

Evaluation of alkalinity spatial distribution in an up-flow fixed bed anaerobic digester

2017 ◽  
Vol 77 (4) ◽  
pp. 948-959 ◽  
Author(s):  
Maha Hmissi ◽  
Jérôme Harmand ◽  
Victor Alcaraz-Gonzalez ◽  
Hedi Shayeb
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Spatial Distribution ◽  
Volatile Fatty Acids ◽  
Fixed Bed ◽  
Control Process ◽  
Fixed Bed Reactor ◽  
Hydrodynamic Behavior ◽  
Sampling Points ◽  
Tequila Vinasses

Abstract In this paper, an experimental study upon alkalinity and hydrodynamic behavior in an anaerobic up-flow fixed bed reactor for the treatment of tequila vinasses is presented. Measurements of volatile fatty acids, pH, alkalinity and bicarbonate were obtained at three sampling points in the reactor in the axial axis. Then, the spatial distribution of alkalinity is studied and discussed. Moreover, for further control process purposes, a hydrodynamic model based on the use of two interconnected two-steps reduced AM2 type models is proposed and its parameters are identified using experimental data.

scholarly journals Condensation By-Products in Wet Peroxide Oxidation: Fouling or Catalytic Promotion? Part II: Activity, Nature and Stability

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 518 ◽  
Author(s):  
Asunción Quintanilla ◽  
Jose L. Diaz de Tuesta ◽  
Cristina Figueruelo ◽  
Macarena Munoz ◽  
Jose A. Casas
Keyword(s):  
Catalyst Deactivation ◽  
Fixed Bed ◽  
Reaction Rates ◽  
Fixed Bed Reactor ◽  
Intrinsic Activity ◽  
Peroxide Oxidation ◽  
Air Oxidation ◽  
Carbonaceous Deposits ◽  
Wet Peroxide Oxidation ◽  
By Products

The deposition of condensation by-products onto the catalyst surface upon wet peroxide and wet air oxidation processes has usually been associated with catalyst deactivation. However, in Part I of this paper, it was demonstrated that these carbonaceous deposits actually act as catalytic promoters in the oxygen-assisted wet peroxide oxidation (WPO-O2) of phenol. Herein, the intrinsic activity, nature and stability of these species have been investigated. To achieve this goal, an up-flow fixed bed reactor packed with porous Al2O3 spheres was used to facilitate the deposition of the condensation by-products formed in the liquid phase. It was demonstrated that the condensation by-products catalyzed the decomposition of H2O2 and a higher amount of these species leads to a higher degree of oxidation degree The reaction rates, conversion values and intermediates’ distribution were analyzed. The characterization of the carbonaceous deposits on the Al2O3 spheres showed a significant amount of condensation by-products (~6 wt.%) after 650 h of time on stream. They are of aromatic nature and present oxygen functional groups consisting of quinones, phenols, aldehydes, carboxylics and ketones. The initial phenol concentration and H2O2 dose were found to be crucial variables for the generation and consumption of such species, respectively.

scholarly journals Synthesis of methanol in microchnnel

2021 ◽  
Vol 2119 (1) ◽  
pp. 012113
Author(s):  
S V Dimov
Keyword(s):  
Experimental Data ◽  
Carbon Monoxide ◽  
Chemical Reactions ◽  
Synthesis Gas ◽  
Methanol Synthesis ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Microchannel Reactor ◽  
Flow Rates ◽  
Synthesis Of Methanol

Abstract Systematic experimental data have been obtained on the results of catalytic chemical reactions in a microchannel reactor for the synthesis of methanol from synthesis gas. Synthesis gas contains hydrogen, carbon monoxide and dioxide, as well as nitrogen in the ratio 58/29/5/8. The experiments were carried out at different flow rates in the temperature range 190-260C. Experiments were also carried out for methanol synthesis in fixed bed reactor at different synthesis pressures.

Simulation Analysis of Fixed Bed Reactor for Au-Cu Non-Mercury Catalytic Acetylene Hydrochlorination

2013 ◽  
Vol 455 ◽  
pp. 94-98 ◽  
Author(s):  
Lei Wang ◽  
Ben Xian Shen ◽  
Ruo Fan Ren ◽  
Ji Gang Zhao
Keyword(s):  
Experimental Data ◽  
Simulation Analysis ◽  
Hot Spot ◽  
Fixed Bed ◽  
Axial Direction ◽  
Fixed Bed Reactor ◽  
Two Dimensional ◽  
Acetylene Hydrochlorination ◽  
Valuable Data ◽  
Operation Conditions

A two-dimensional pseudo-homogenous mathematical model was established according to the Au-Cu non-mercury catalytic reaction kinetics. The Crank-Nicholson method was used to solve the equations on the basis of experimental data. The results showed that a violent reaction at the entrance of the fixed bed reactor led to a hot spot in the acetylene hydrochlorination reaction over the Au-Cu Non-mercury catalyst. The conversion increased rapidly initially, and then flattened gradually in the axial direction. The result of simulation provided valuable data to optimize the design of reactor and the industrial operation conditions.

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