A Review of Mass Transfer Controlling the Reaction Rate in Heterogeneous Catalytic Systems

Klaewkla, Raweewan; Arend, Matthias G.; Hoelderich, Wolfgang F.

doi:10.5772/22962

Cited by 103 publications

(94 citation statements)

References 11 publications

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“…Increasing the superficial gas velocity will lead to an increase in the degree of agitation and gas-to-particle heat transfer. In the gas-solid reaction, the mass transfer of the gas first takes place from the main stream of fluid to the external surface of the particle [58]. A series of five tests were achieved at temperature 750 °C and ER = 0.2 to investigate the effect of external diffusion on the gasification of AROK and are shown in Fig.…”

Section: Influence Of Superficial Gas Velocity On Gasificationmentioning

confidence: 99%

Kinetics and Performance of Raw and Torrefied Biomass in a Continuous Bubbling Fluidized Bed Gasifier

Al-Farraji

Marsh

Steer

et al. 2017

Waste Biomass Valor

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This paper is an experimental study of the kinetics of gasification of olive kernel by using a thermogravimetric fluidized bed reactor technique. Gasification of 'as received' and torrefied olive kernels were investigated in a lab-scale bubbling fluidized bed gasifier, operating at up to 3.2 kg/h. The effect of bed temperature between 550 and 750 °C in 50 °C increments on the gasification product gas at mass-based equivalence ratios of 0.15 and 0.2 was studied. To explore the potential of torrefied biomass, the gasification results were compared to that of the 'as received' biomass. The product gas from torrefied biomass produced higher H 2 , CO and CH 4 concentrations at identical oxidant flow rates in addition to higher cold gas efficiency and higher product gas heating value. The influence of equivalence ratio in gasification was also investigated at reactor temperatures of 750 °C and five equivalence ratios (0.15, 0.2, 0.25, 0.3, and 0.35). The results revealed that the torrefied biomass has the highest HHV at an equivalence ratio of 0.2 with a value of 6.09 MJ/Nm 3 , while 'as received' biomass 4.72 MJ/Nm 3 . Kinetic experiments under isothermal conditions were performed for the gasification of the materials in continuous mode. A mass balance model was successfully used to provide the capability of separately determining the rate constant of the reactions taking place. The kinetic parameters were calculated by a first order reaction model giving activation energies for 'as received' olive kernels of 84 kJ/mol and for torrefied olive kernels of 106 kJ/mol.

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Section: Influence Of Superficial Gas Velocity On Gasificationmentioning

confidence: 99%

Kinetics and Performance of Raw and Torrefied Biomass in a Continuous Bubbling Fluidized Bed Gasifier

Al-Farraji

Marsh

Steer

et al. 2017

Waste Biomass Valor

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“…However, it is important to remember that the average timescale of acquiring a spectrum (typically up to 1 min) can be incompatible with fast catalytic reactions (typically ms or s). Furthermore, for heterogeneous reaction mixtures (either solid-liquid, liquid-liquid, or liquid-gas), the issue of mass transfer is an important consideration [23]. In theory, any heterogeneous reactions would ultimately encounter mass transfer limitations.…”

Section: Indirect Methods For Detecting Catalyst Leachingmentioning

confidence: 99%

Catalysis in Flow: Why Leaching Matters

Hii

Hellgardt

2015

Organometallic Flow Chemistry

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“…78 Thrust generated via decomposition of H 2 O 2 fuel is therefore dependent on the introduction rate of the fuel to the Pt-CNT-MM surface.…”

mentioning

confidence: 99%

High Aspect Ratio Carbon Nanotube Membranes Decorated with Pt Nanoparticle Urchins for Micro Underwater Vehicle PropulsionviaH₂O₂Decomposition

et al. 2015

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The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial agility is often impaired when maneuvers require burst-propulsion. Herein we develop highaspect ratio (150:1), multiwalled carbon nanotube microarray membranes (CNT-MMs) for propulsive, MUV thrust generation by the decomposition of hydrogen peroxide (H 2 O 2 ). The CNT-MMs are grown via chemical vapor deposition with diamond shaped pores (nominal diagonal dimensions of 4.5 × 9.0 μm) and subsequently decorated with urchin-like, platinum (Pt) nanoparticles via a facile, electroless, chemical deposition process. The Pt-CNT-MMs display robust, high catalytic ability with an effective activation energy of 26.96 kJ mol -1 capable of producing a thrust of 0.209 ± 0.049 N from 50% [w/w] H 2 O 2 decomposition within a compact reaction chamber of eight Pt-CNT-MMs in series. A n upward trend in the research and use of unmanned underwater vehicles (UUVs), and in particular micro underwater vehicles (MUVs, small UUVS between 1 and 50 cm in length), for exploration of confined spaces such as ship wrecks, submerged oil pipelines, and various military purposes has been observed over recent years. 1À3 The locomotion of these vehicles is typically controlled by propellerbased systems, which are often used for long-endurance missions. 4À6 However, propeller-based systems are usually limited in their ability to perform tight radius turns, burst-driven docking maneuvers, and lowspeed course corrections. ABSTRACT The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial

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A Review of Mass Transfer Controlling the Reaction Rate in Heterogeneous Catalytic Systems

Cited by 103 publications

References 11 publications

Kinetics and Performance of Raw and Torrefied Biomass in a Continuous Bubbling Fluidized Bed Gasifier

Kinetics and Performance of Raw and Torrefied Biomass in a Continuous Bubbling Fluidized Bed Gasifier

Catalysis in Flow: Why Leaching Matters

High Aspect Ratio Carbon Nanotube Membranes Decorated with Pt Nanoparticle Urchins for Micro Underwater Vehicle PropulsionviaH₂O₂Decomposition

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A Review of Mass Transfer Controlling the Reaction Rate in Heterogeneous Catalytic Systems

Cited by 103 publications

References 11 publications

Kinetics and Performance of Raw and Torrefied Biomass in a Continuous Bubbling Fluidized Bed Gasifier

Kinetics and Performance of Raw and Torrefied Biomass in a Continuous Bubbling Fluidized Bed Gasifier

Catalysis in Flow: Why Leaching Matters

High Aspect Ratio Carbon Nanotube Membranes Decorated with Pt Nanoparticle Urchins for Micro Underwater Vehicle PropulsionviaH2O2Decomposition

Contact Info

Product

Resources

About

High Aspect Ratio Carbon Nanotube Membranes Decorated with Pt Nanoparticle Urchins for Micro Underwater Vehicle PropulsionviaH₂O₂Decomposition