A review of recent advances in numerical simulations of microscale fuel processor for hydrogen production

Holladay, Johnathan E.; Wang, Yong

doi:10.1016/j.jpowsour.2015.01.079

Cited by 35 publications

(38 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They are also able to improve the designs to achieve the desired performance. Furthermore, the numerical simulation tools have proven to be extremely useful in evaluating new designs, understanding the manifold impact on flow distribution, and projecting thermal distribution and efficiency (Holladay and Wang, 2015). To illustrate the primary mechanism, a relatively simple system may provide valuable insights.…”

Section: Computational Fluid Dynamics Modelmentioning

confidence: 99%

CFD Modeling of the Combustion Characteristics and Stability in Catalytic Micro-Channels

Junjie¹,

Xu²

2017

AJHMT

View full text Add to dashboard Cite

Combustion characteristics and stability of premixed methane-air mixtures in catalytic micro-channels is studied numerically, using CFD (computational fluid dynamics). The characteristics of the fluid mechanics are also analyzed. A two-dimensional CFD model with detailed reaction mechanisms and multicomponent transport is developed to evaluate the effect of operating conditions on the combustion stability. The laminar flow is assumed, and steady-steady simulations are performed. The fuel-lean equivalence ratio operation limit for the system is determined by the analysis of Reynolds number. The primary focus is on CFD as a means of understanding thermal management at small scales. It is shown that an appropriate choice of the flow velocity is crucial in achieving the self-sustained operation. Large gradients in temperature and species concentration are observed, despite the small scales of the system under certain conditions. The flow velocity is very important as it determines the flame location. Furthermore, the flow velocity plays a dual, competing role in the stability of the system. Low flow velocities reduce the heat generation, whereas high flow velocities reduce the convective time-scale. There is a narrow regime of flow velocities that allows self-sustained operation. When a low-power system is desired, highly insulating materials should be preferred, whereas a high-power system would favor highly conductive materials. Engineering maps that delineate combustion stability are constructed. In order to gain further insight into the combustion characteristics of the system, the optimum Reynolds number is determined. Finally, design recommendations are made.

show abstract

Section: Computational Fluid Dynamics Modelmentioning

confidence: 99%

CFD Modeling of the Combustion Characteristics and Stability in Catalytic Micro-Channels

Junjie¹,

Xu²

2017

AJHMT

View full text Add to dashboard Cite

show abstract

“…Development of efficient and low cost hydrogen production technologies is an urgent task due to the increased demand of clean energy generation [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. At present more than 50 million tons of hydrogen are produced annually worldwide and much of this hydrogen is used in the chemical and refinery industries [15].…”

Section: Introductionmentioning

confidence: 99%

“…Although the "green" or carbon-neutral path from current fossil-based to future hydrogen economy is preferable and provides sustainable development [1][2][3][4], to date H 2 is usually produced from fossil fuels without CO 2 capture and storage [16,10,13]. Natural gas remains main feedstock for hydrogen production [8,13,14,16,17]. The typical technologies for production of hydrogen from natural gas are steam methane reforming (SMR), partial oxidation (POX) and autothermal reforming (ATR).…”

Section: Introductionmentioning

confidence: 99%

Application of POSS Nanotechnology for Preparation of Efficient Ni Catalysts for Hydrogen Production

Исмагилов

Матус

Kuznetsov

et al. 2017

Eurasian Chem. Tech. J.

View full text Add to dashboard Cite

POSS (polyhedral oligomeric silsesquioxanes) nanotechnology was applied for preparation of efficient Ni catalysts for hydrogen production through autothermal reforming of methane (ATR of CH 4 ). The novel metal-POSS precursor [Nickel (II) -HeptaisobutylPOSS (C 4 H 9 ) 7 Si 7 O 9 (OH)O 2 Ni] of Ni nanoparticles was introduced into Ce 0.5 Zr 0.5 O 2 support with following calcination and reduction stages of activation. The peculiarity of the genesis of Ni/SiO 2 /Ce 0.5 Zr 0.5 O 2 nanomaterials and their characteristics versus deposition mode were studied by X-ray fluorescence spectroscopy, thermal analysis, N 2 adsorption, X-ray diffraction, high-resolution transmission electron microscopy and H 2 temperature-programmed reduction. The two kinds of supported Ni-containing particles were observed: highly dispersed Ni forms (1-2 nm) and large Ni-containing particles (up to 50-100 nm in size). It was demonstrated that the textural, structural, red-ox and, consequently, catalytic properties of ex-Ni-POSS catalysts depend on the deposition mode. The increase of a portion of difficultly reduced Ni 2+ species is found upon application of intermediate calcination during Ni-POSS deposition that has detrimental effect on the activity of catalyst in ATR of CH 4 . The Ni/SiO 2 /Ce 0.5 Zr 0.5 O 2 catalyst prepared by one-step Ni-POSS deposition exhibits the highest H 2 yield -80% at T = 800 °C.

show abstract

“…Steam reforming is a strongly endothermic reaction and heat must be supplied to the system by an external device [13]. In order to maximize the hydrogen yield, an excess of water is usually fed to carry out the water-gas shift reaction [14]. Ethanol steam reforming is a very complex reaction where many reaction pathways are possible [15].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Production by the Steam Reforming of Bio-Ethanol over Nickel-Based Catalysts for Fuel Cell Applications

Chen¹,

Xu²

2017

IJSGE

View full text Add to dashboard Cite

Abstract:The bio-ethanol steam reforming over nickel-based catalysts when the temperature is within the range of 700 to 800 K is studied for fuel cell applications. The effect of operating conditions such as the temperature, space time, water-to-ethanol molar ratio, and oxygen-to-ethanol molar ratio on the product distribution is evaluated. The water-gas shift reaction is examined in the reforming process. Adjusting feed ratios to favor carbon removal from the surface is discussed in detail. It is shown that a nickel-supported-on-alumina catalyst completely converts bio-ethanol and high hydrogen yields are obtained. High temperatures and water-to-ethanol ratios can promote hydrogen production. There is no evidence that the water-gas shift reaction occurs over nickel-based catalysts. Carbon formation can be minimized by using high water-to-ethanol ratios. The presence of oxygen in the feed plays a favorable effect on the carbon deposition, but the carbon monoxide production is not reduced. There are several reaction pathways that could occur in the bio-ethanol steam reforming process, and the catalyst produces ethylene and acetaldehyde as intermediate products. The region of carbon formation depends on the temperature as well as the water-to-ethanol and oxygen-to-ethanol molar ratios. Finally, an overall reaction scheme as a function of temperature is proposed. The best catalysts appear to be those that are sufficiently basic to inhibit the dehydration of ethanol to ethylene, which subsequently polymerizes and causes coke formation.

show abstract

A review of recent advances in numerical simulations of microscale fuel processor for hydrogen production

Cited by 35 publications

References 52 publications

CFD Modeling of the Combustion Characteristics and Stability in Catalytic Micro-Channels

CFD Modeling of the Combustion Characteristics and Stability in Catalytic Micro-Channels

Application of POSS Nanotechnology for Preparation of Efficient Ni Catalysts for Hydrogen Production

Hydrogen Production by the Steam Reforming of Bio-Ethanol over Nickel-Based Catalysts for Fuel Cell Applications

Contact Info

Product

Resources

About