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Showing papers on "Packed bed published in 2010"


Journal ArticleDOI
TL;DR: In this article, a review of the literature describing the packing structure and effective thermal conductivity of randomly packed beds consisting of mono-sized particles is presented, with particular attention paid to the packing structures (porosity, coordination number, and contact angles) and heat transfer.

332 citations


Journal ArticleDOI
TL;DR: In this article, an extensive review on the research carried out on packed beds is presented, which includes the design of packed beds, materials used for storage, heat transfer enhancement, flow phenomenon and pressure drop through packed beds.
Abstract: Because of intermittent nature of solar energy, storage is required for uninterrupted supply in order to match the needs. Packed beds are generally used for storage of thermal energy from solar air heaters. A packed bed is a volume of porus media obtained by packing particles of selected material into a container. A number of studies carried out on packed beds for their performance analysis were reported in the literature. These studies included the design of packed beds, materials used for storage, heat transfer enhancement, flow phenomenon and pressure drop through packed beds. This paper presents an extensive review on the research carried out on packed beds. Based on the literature review, it is concluded that most of the studies carried out are on rocks and pebbles as packing material. A very few studies were conducted on large sized packing materials. Further no study has been reported so far on medium sized storage elements in packed beds.

271 citations


Journal ArticleDOI
TL;DR: In this paper, a post-combustion CO2 capture process based on cryogenic CO2 freeze-out in dynamically operated packed beds is proposed and developed, based on the differences in dew and sublimation points.

246 citations


Patent
07 Jul 2010
TL;DR: In this paper, an on-chip packed reactor bed design that allows for an effective exchange of packing materials such as beads at a miniaturized level is presented. But this design can be further extended to include integrated packed bed immuno- or enzyme reactors.
Abstract: The present invention provides an on-chip packed reactor bed design that allows for an effective exchange of packing materials such as beads at a miniaturized level. The present invention extends the function of microfluidic analysis systems to new applications including on-chip solid phase extraction (SPE) and on-chip capillary electrochromatography (CEC). The design can be further extended to include integrated packed bed immuno- or enzyme reactors.

200 citations


Journal ArticleDOI
TL;DR: In this article, the effects of packing form and particle shape on the flow and heat transfer inside small pores of some novel structured packed beds are numerically studied, where the packed beds with ellipsoidal or non-uniform spherical particles are investigated for the first time and some new transport phenomena are obtained.

173 citations


Journal ArticleDOI
TL;DR: In this paper, the performance of SCMFC with the packed bed anode configuration was studied using a mixed microorganism culture from real wastewaters in batch and continuous mode operation.

169 citations


Journal ArticleDOI
TL;DR: In this paper, a theoretical model for the tortuosity of a fixed bed randomly packed with identical particles has been developed, which is proportional to a packing structure factor ( ( 1 − e ) 4 / 3 / e φ 2 ) which is explicitly given in terms of bed voidage and particles shape factor (sphericity).

151 citations


Journal ArticleDOI
01 Sep 2010-Energy
TL;DR: In this article, the thermal performances of single and double pass solar air heaters with steel wire mesh layers instead of a flat absorber plate are investigated experimentally and the effects of mass flow rate of air on the outlet temperature and thermal efficiency were studied.

140 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigate the transport and transfer properties inside packed beds of spherical particles by means of CFD simulations and show that this treatment has very little influence on the results when analyzed with dimensionless numbers as Nu=f(Re, Pr) or Sh=f (Re, Sc).

121 citations


Journal ArticleDOI
01 May 2010-Energy
TL;DR: In this article, an effective packed bed model was developed, which could investigate the flow field as the fluid flows through the voids of the phase change material (PCM), and at the same time could account for the thermal gradients inside the PCM spheres.

117 citations


ReportDOI
01 Aug 2010
TL;DR: In this article, the authors present an overview of the torrefaction process and do a literature review on the physical properties of torrefied raw material and torref reaction gas composition.
Abstract: The world is currently facing challenges to reduce the dependence on fossil fuels and to achieve a sustainable renewable supply. Renewable energies represent a diversity of energy sources that can help to maintain the equilibrium of different ecosystems. Among the various sources of renewable energy, biomass is finding more uses as it is considered carbon neutral since the carbondioxide released during its use is already part of the carbon cycle (Arias et al., 2008). Increasing the utilization of biomass for energy can help to reduce the negative CO2 impact on the environment and help to meet the targets established in the Kyoto Protocol (UN, 1998). Energy from biomass can be produced from different processes like thermochemical (combustion, gasification, and pyrolysis), biological (anaerobic digestion, fermentation) or chemical (esterification) where direct combustion can provide a direct near-term energy solution (Arias et al., 2008). Some of the inherent problems with raw biomass materials, like low bulk density, high moisture content, hydrophilic nature and low calorific value, limit the ease of use of biomass for energy purposes (Arias et al., 2008). In fact, due to its low energy density compared to fossil fuels, high volumes of biomass will be needed; adding to problems associated with storage, transportation and feed handling at a cogeneration plant. Furthermore, grinding biomass pulverizes, can be very costly and in some cases impractical. All of these drawbacks have given rise to the development of new technologies in order to increase the quality of biomass fuels. The purpose of the work is mainly in four areas 1) Overview of the torrefaction process and to do a literature review on i) Physical properties of torrefied raw material and torrefaction gas composition. 2) Basic principles in design of packed bed i) Equations governing the flow of material in packed bed ii) Equations governing the flow of the gases in packed bed iii) Effect of physical properties of the raw materials on the packed bed design 3) Design of packed bed torrefier of different capacities. 4) Development of an excel sheet for calculation of length and diameter of the packed bed column based on the design considerations.

Journal ArticleDOI
TL;DR: In this paper, the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, has been compared for ultra-pure hydrogen production via methane reforming using detailed theoretical models, the required membrane area to reach a given conversion and the prevailing temperature profiles have been compared.

Journal ArticleDOI
TL;DR: In this article, commercially available zeolites (CBV28014, CBV901) with a high Si/Al ratio were tested as adsorbents to recover 1-butanol from aqueous solutions such as acetone butanol-ethanol fermentation broth.


Journal ArticleDOI
TL;DR: In this article, a packed bed chemical-looping combustion was investigated experimentally to provide an experimental proof-of-principle, using information obtained from both the reduction and oxidation cycles, the measured maximum temperature rise and front velocities in the packed bed during the oxidation cycle correspond with analytical expressions describing the system, especially when the contribution of the formation of carbon during the reduction cycle was taken into account.

Journal ArticleDOI
TL;DR: In this paper, two types of novel porous plate packing were investigated respectively in a cross-flow rotating packed bed to examine their gas pressure drop and mass transfer characteristics with CO2−NaOH solution system.
Abstract: Structured packing were proposed and designed according to gas−liquid mass transfer and kinetic balance characteristics in a cross-flow rotating packed bed (RPB). Two types of novel porous plate packing were investigated respectively in a cross-flow RPB to examine their gas pressure drop and mass transfer characteristics with CO2−NaOH solution system. Compared with the literature, the pressure drop of the cross-flow rotating packed bed with new structured packing was slower than that of wire-gauze packing and was no more than a tenth that of the countercurrent rotating packed bed in the same operational condition. The volume mass transfer coefficient of RPB with new structured packing was higher than that with wire-gauze packing, which was higher than that of countercurrent RPB and was 1−2 orders of magnitude higher than that of the conventional packed tower. Moreover, the correlative expressions of gas pressure drop and volume mass transfer coefficients of RPB were obtained using the MATLAB program and i...

Journal ArticleDOI
TL;DR: High purity hydrogen was produced at 600 degrees C and 1 atm by steam reforming of waste cooking oil at a molar steam to carbon ratio of 4 using chemical looping, a process that features redox cycles of a Ni catalyst with the in-situ carbonation/calcination of a CO(2) sorbent (dolomite) in a packed bed reactor under alternated feedstreams of fuel-steam and air.

Journal ArticleDOI
TL;DR: The performances of 2.1mmx150mm columns packed with a new type of sub-2microm particles, the superficially porous Kinetex-C(18), and with the classical 1.7microm BEH-C (18) fully porous particles were measured and are discussed.

Journal ArticleDOI
TL;DR: In this article, a butanol production process by immobilized Clostridium acetobutylicum in a continuous packed bed reactor (PBR) using Tygon® rings as a carrier was reported.
Abstract: In this study, we report on a butanol production process by immobilized Clostridium acetobutylicum in a continuous packed bed reactor (PBR) using Tygon® rings as a carrier. The medium was a solution of lactose (15–30 g/L) and yeast extract (3 g/L) to emulate the cheese whey, an abundant lactose-rich wastewater. The reactor was operated under controlled conditions with respect to the pH and to the dilution rate. The pH and the dilution rate ranged between 4 and 5, the dilution rate between 0.54 and 2.4 h−1 (2.5 times the maximum specific growth rate assessed for suspended cells). The optimal performance of the reactor was recorded at a dilution rate of 0.97 h−1: the butanol productivity was 4.4 g/Lh and the selectivity of solvent in butanol was 88%w.

Journal ArticleDOI
TL;DR: In this paper, the thermal conductivity of solid ceramic sponges made of alumina, mullite and oxidic-bonded silicon carbide (OBSiC) at moderate temperatures is investigated.

Journal ArticleDOI
TL;DR: Repeated cycling revealed some output oscillations in reactant conversion and in the extent of Ni-NiO conversion, but did not exhibit deterioration by the 6th cycle, resulting in a repeatable syngas composition with H(2) selectivity very close to the optimum.

Journal ArticleDOI
TL;DR: The nature of the packing material remarkable influenced the process performances, by greatly affecting the biofilm bacterial community structure, which can be exploited in the biotechnological production of polyhydroxyalkanoates.

Journal ArticleDOI
TL;DR: In this article, a metal monolith catalyst has been applied for NG steam reforming to increase heat transfer efficiency, which is mainly due to enhanced heat-transfer via metal monolithic catalyst, and the heat flux obtained in the monolithic bed reactor was about twice higher than that in the packed bed reactor.

Journal ArticleDOI
Zhi Qian1, Lianbin Xu1, Li Zhenhu1, Hua Li1, Kai Guo1 
TL;DR: In this article, the authors investigated the selective absorption of H2S from a gas mixture with CO2 into N-methyldiethanolamine (MDEA) in a rotating packed bed (RPB).
Abstract: In this work, selective absorption of H2S from a gas mixture with CO2 into N-methyldiethanolamine (MDEA) is investigated experimentally and theoretically in a rotating packed bed (RPB). In the RPB, various rotating speeds, gas flow rates, liquid flow rates, and concentrations of MDEA aqueous solutions were studied by means of the evaluation of removal efficiency, selectivity, and overall volumetric mass transfer coefficient. The reaction−diffusion mass transfer model based on penetration theory for the selective absorption process is developed, accordingly. The results of experiment and model show that the uppermost function of RPB in selective absorption of H2S is to restrain the CO2 removal efficiency but sharply intensify the absorption of H2S. The mass transfer coefficient of CO2 absorption is enhanced in RPB. However, the total amount of CO2 mass transfer virtually is low because of the short gas−liquid contact time, small volume of packing, and large gas−liquid ratio within the RPB, and the CO2 remo...

Journal ArticleDOI
TL;DR: The derivatization process of the pristine nanotubes was a key factor to achieve a successful separation of both the light n-alkanes and related isomers and Satisfactory results were similarly obtained in the case of separation of aromatic hydrocarbons.

Journal ArticleDOI
TL;DR: This study presents the external mass transfer effects on the reduction of hexavalent chromium (Cr(VI) using calcium alginate immobilized Bacillus sp.

Journal ArticleDOI
TL;DR: In this article, an algorithm for random close packing of polydisperse particles is presented which can be used for arbitrary pebble bed containing geometries, and the microstructure of a packed bed in both the bulk and near-wall regions can be determined.

Journal ArticleDOI
TL;DR: In this paper, the effects of pyrolytic gasification temperature, catalyst content, steam reforming temperature, and weight hourly space velocity for a Ru catalyst used in a 60g−h−1-scale continuous experimental apparatus was evaluated.

Journal ArticleDOI
TL;DR: In this paper, the hydrogen production from NH3 decomposition for fuel cell applications using packed Ni-Pt/Al2O3 particles as the catalyst is theoretically and numerically predicted.

Journal ArticleDOI
TL;DR: In this paper, an impinging stream-rotating packed bed (IS-RPB) was proposed for improving the micromixing efficiency of iodide and iodate.