Modeling and Comparison a Thermally Coupled Reactor of Methane Tri – Reforming and Dehydrogenation of Cyclohexane Reactions for Syngas Production in Both Co- & Counter-Current Modes

2018 ◽  
Vol 17 (1) ◽  
Author(s):  
E. Dehghanfard ◽  
Z. Arab Aboosadi
Keyword(s):  
Fixed Bed ◽  
Current Mode ◽  
Superior Performance ◽  
Hydrogen Yield ◽  
The Novel ◽  
One Dimensional ◽  
Syngas Production ◽  
Dehydrogenation Of Cyclohexane ◽  
Double Pipe ◽  
Counter Current

Abstract The aim of this work is a comparison of different inlets (Co- and Counter-current modes) to feed a thermally coupled reactor (TCR) in producing syngas as a valuable chemical. The novel thermally coupled reactor has been designed as a double pipe reactor where tri-reforming of methane for syngas production has been considered in the exothermic side of fixed bed plug reactor, and dehydrogenation of cyclohexane reaction occur in the endothermic side. The heat generated in the exothermic part by the walls of the tube side is transferred to the endothermic section. A steady-state homogeneous one-dimensional model predicts the performance of this reactor for simultaneous production of synthesis gas and benzene in an economical approach for both co- and counter-current modes of operation. The reversed flow of cyclohexane has been considered for the counter-current flow regime. The simulation results of co- and counter-current modes of TCR and also an optimized tri-reforming of methane (OTRM) single reactor are investigated and compared with each other. The results showed that methane conversion, hydrogen yield and ${H_2}/Co$ ratio in the exothermic side of TCR reached to 91.1 %, 1.82 and 2.1 in co-current mode and 87.8 %, 1.77 and 2.3 in counter-current mode, respectively. Additionally, the results showed that cyclohexane conversion at the endothermic side of the reactor in co- and counter-current modes achieved to 98.6 % and 99.9 %, respectively. So, the results for counter-current mode showed superior performance in hydrogen and benzene production in the endothermic side of TCR. Also, Changes in various operating parameters during the reactor have been studied.

Performance Study of a Thermally Double Coupled Multi-Tubular Reactor by Considering the Effect of Flow Type Patterns

2016 ◽  
Vol 14 (1) ◽  
pp. 63-78 ◽  
Author(s):  
Mohsen Abbasi ◽  
Mehdi Farniaei ◽  
Sedigheh Kabiri ◽  
Mohammad Reza Rahimpour ◽  
Saeid Abbasi
Keyword(s):  
Current Flow ◽  
Tubular Reactor ◽  
Current Mode ◽  
Superior Performance ◽  
Performance Study ◽  
Reversed Flow ◽  
One Dimensional ◽  
Production Of Hydrogen ◽  
Simulation Results ◽  
Counter Current

AbstractIn this study, a steady-state heterogeneous one-dimensional model predicts the performance of a thermally double coupled auto-thermal multi-tubular reactor for simultaneous production of hydrogen, benzene, methanol and dimethyether (DME) in an economical approach for both co- and counter- current modes of operation. Reversed flow of cyclohexane has been considered for the counter-current flow regime. The simulation results for co- and counter-current modes have been investigated and compared with corresponding predictions for conventional methanol reactor and traditional coupled methanol reactor. In addition, various operating parameters along the reactor have been studied. The simulation results present that methanol yield in co- and counter- current modes are reached to 0.3735 and 0.3363 in a thermally double coupled reactor, respectively. Also, results for counter-current mode show a superior performance in hydrogen and benzene production. Finally, the results of simulation illustrate that the coupling of these reactions could be beneficial.

scholarly journals Topological correlators and surface defects from equivariant cohomology

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Rodolfo Panerai ◽  
Antonio Pittelli ◽  
Konstantina Polydorou
Keyword(s):  
Quantum Mechanics ◽  
Equivariant Cohomology ◽  
Surface Defects ◽  
Star Product ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional System ◽  
The Novel ◽  
One Dimensional ◽  
Dual Quantum

Abstract We find a one-dimensional protected subsector of $$ \mathcal{N} $$ N = 4 matter theories on a general class of three-dimensional manifolds. By means of equivariant localization we identify a dual quantum mechanics computing BPS correlators of the original model in three dimensions. Specifically, applying the Atiyah-Bott-Berline-Vergne formula to the original action demonstrates that this localizes on a one-dimensional action with support on the fixed-point submanifold of suitable isometries. We first show that our approach reproduces previous results obtained on S3. Then, we apply it to the novel case of S2× S1 and show that the theory localizes on two noninteracting quantum mechanics with disjoint support. We prove that the BPS operators of such models are naturally associated with a noncom- mutative star product, while their correlation functions are essentially topological. Finally, we couple the three-dimensional theory to general $$ \mathcal{N} $$ N = (2, 2) surface defects and extend the localization computation to capture the full partition function and BPS correlators of the mixed-dimensional system.

Synthesis of New Chalcogenide Materials. The Novel One-Dimensional Semiconductor K4 Ti3 S14

1987 ◽  
Vol 97 ◽  
Author(s):  
Steven A. Sunshine ◽  
Doris Kang ◽  
James A. Ibers
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Alkali Metal ◽  
The Novel ◽  
Conductivity Measurements ◽  
One Dimensional ◽  
General Utility ◽  
Solid State Materials ◽  
Chalcogenide Materials

ABSTRACTThe use of A2 Q/Q melts (A - alkali metal, Q - S or Se) for the synthesis of new one-dimensional solid-state materials is found to be of general utility and is illustrated here for the synthesis of K4 Ti3 SI4. Reaction of Ti metal with a K2 S/S melt at 375°C for 50 h affords K4 Ti3 SI4. The structure possesses one-dimensional chains of seven and eightcoordinate Ti atoms with each chain isolated from all others by surrounding K atoms. There are six S-S pairs (dave - 2.069(3) Å) so that the compound is one of TiIV and may be described as K4 [Ti3 (S)2 (S2)6]. Electrical conductivity measurements indicate that this material is a semiconductor.

scholarly journals Self-Consistent Solution of the Multi Band Boltzmann, Poisson and Hole-Continuity Equations

VLSI Design ◽  
1998 ◽  
Vol 6 (1-4) ◽  
pp. 257-260
Author(s):  
Surinder P. Singh ◽  
Neil Goldsman ◽  
Isaak D. Mayergoyz
Keyword(s):  
Boltzmann Transport Equation ◽  
The Novel ◽  
Boltzmann Transport ◽  
One Dimensional ◽  
Bipolar Junction Transistor ◽  
Continuity Equations ◽  
The Poisson Equation ◽  
Curvilinear Grid ◽  
Consistent Solution ◽  
Junction Transistor

The Boltzmann transport equation (BTE) for multiple bands is solved by the spherical harmonic approach. The distribution function is obtained for energies greater than 3 eV. The BTE is solved self consistently with the Poisson equation for a one dimensional npn bipolar junction transistor (BJT). The novel features are: the use of boundary fitted curvilinear grid, and Scharfetter Gummel type discretization of the BTE.

scholarly journals Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

2016 ◽  
Vol 11 (2) ◽  
pp. 220 ◽  
Author(s):  
Norazimah Harun ◽  
Jolius Gimbun ◽  
Mohammad Tazli Azizan ◽  
Sumaiya Zainal Abidin
Keyword(s):  
Carbon Dioxide ◽  
Tubular Reactor ◽  
Dry Reforming ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Impregnation Method ◽  
Glycerol Conversion ◽  
Syngas Production

<p>The carbon dioxide (CO<sub>2</sub>) dry reforming of glycerol for syngas production is one of the promising ways to benefit the oversupply crisis of glycerol worldwide. It is an attractive process as it converts carbon dioxide, a greenhouse gas into a synthesis gas and simultaneously removed from the carbon biosphere cycle. In this study, the glycerol dry reforming was carried out using Silver (Ag) promoted Nickel (Ni) based catalysts supported on silicon oxide (SiO<sub>2</sub>) i.e. Ag-Ni/SiO<sub>2</sub>. The catalysts were prepared through wet impregnation method and characterized by using Brunauer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Thermo Gravimetric (TGA) analysis. The experiment was conducted in a tubular reactor which condition fixed at 973 K and CO<sub>2</sub>:glycerol molar ratio of 1, under atmospheric pressure. It was found that the main gaseous products are H₂, CO and CH<sub>4</sub> with H₂:CO molar ratio &lt; 1.0. From the reaction study, Ag(5)-Ni/SiO<sub>2</sub> results in highest glycerol conversion and hydrogen yield, accounted for 32.6% and 27.4%, respectively. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 22<sup>nd</sup> January 2016; Revised: 22<sup>nd</sup> February 2016; Accepted: 23<sup>rd</sup> February 2016</em></p><strong>How to Cite</strong>: Harun, N., Gimbun, J., Azizan, M.T., Abidin S.Z. (2016). Characterization of Ag-promoted Ni/SiO<sub>2</sub> Catalysts for Syngas Production via Carbon Dioxide (CO<sub>2</sub>) Dry Reforming of Glycerol. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (2): 220-229 (doi:10.9767/bcrec.11.2.553.220-229)<p><strong>Permalink/DOI:</strong> http://dx.doi.org/10.9767/bcrec.11.2.553.220-229</p>

scholarly journals Hydrogen rich product gas from air-steam gasification of Indian biomasses with waste engine oil as binder

2021 ◽  
Author(s):  
Prashant Sharma ◽  
Bhupendra Gupta ◽  
Mukesh Pandey
Keyword(s):  
Equivalence Ratio ◽  
Calorific Value ◽  
Steam Gasification ◽  
Engine Oil ◽  
Small Scale ◽  
Hydrogen Yield ◽  
Syngas Production ◽  
Waste Engine Oil ◽  
Product Gas ◽  
Biomass Ratio

Abstract Present study concerns with the production of H2 rich product gas by thermochemical energy conversion having biomass gasification as a route for the four biomasses i.e., Kasai Saw Dust, Lemon Grass, Wheat Straw and Pigeon Pea Seed Coat. The biomasses are from the family of woody biomass, grasses, agricultural waste and food process industry wastes. Waste engine oil as an additive is used, which also acts as a binder. Air gasification and Air-steam gasification is applied and compared for product gas composition, hydrogen yield and other performance parameters like lower heating value, energy yield. Product gas constituents, hydrogen production is examined with different steam to biomass ratio (S/B ratio) and equivalence ratio. The equivalence ratio varies from 0.20–0.40 and the steam to biomass ratio varies between 0–4. The waster engine oil is mixed with the biomasses with different percentage of 5 and 10 wt%. For enhancement of feedstock quality palletization process is applied. The H2 yield is greatly affected by the equivalence ratio. Results show maximum H2 production and higher calorific value of product gas at an air to fuel of 0.26 for all the biomass pallets. Also, the S/B ratio observed as important aspect for hydrogen enrichment. Hydrogen yield is maximum at 2.4 steam to biomass ratio. This study considers the rarely studied Indian biomasses with waste engine oil as an additive for hydrogen-rich product gas production and will be beneficial for small scale hydrogen-rich syngas production considering the central Indian region originated biomasses. Statement of Novelty (SON): Research work belongs to eco-friendly use of rarely studied Indian biomass pallets. Equivalence air to fuel ratio (E/R ratio), steam to biomass ratio (S/B ratio) and waste engine oil as additive have been considered to upgrade H2 content and Calorific Value (CV) of the product gas. Novelty of work include use of waste engine oil as additive to make biomass pallets.

scholarly journals Co-digestion of Oil Palm Trunk Hydrolysate and Slaughterhouse Wastewater for Biohydrogen Production in a Fixed Bed Reactor by Immobilized Thermoanaerobacterium thermosaccharolyticum KKU19 on Expanded Clay

2021 ◽  
Vol 9 ◽  
Author(s):  
Sontaya Khamtib ◽  
Sureewan Sittijunda ◽  
Tsuyoshi Imai ◽  
Alissara Reungsang
Keyword(s):  
Oil Palm ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Hydrogen Yield ◽  
Support Material ◽  
Slaughterhouse Wastewater ◽  
Term Operation ◽  
Oil Palm Trunk ◽  
Thermoanaerobacterium Thermosaccharolyticum

The goal of this study was to evaluate the use of expanded clay as a support material for Thermoanaerobacterium thermosaccharolyticum KKU19 to produce hydrogen from oil palm trunk hydrolysate (OPT) and slaughterhouse wastewater (SHW) in a fixed-bed reactor (FBR) under non-sterile conditions. The effects of hydraulic retention time (HRT) on the performance of the FBR were also investigated. The FBR was operated at an OPT hydrolysate to SHW ratio of 2.55:1 (v:v), 60°C, initial pH 6.5, and 1.2 mg (as total volatile solids/g expanded clay) of T. thermosaccharolyticum KKU19 immobilized on expanded clay. A maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 7.15 ± 0.22 L/L day and 234.45 ± 5.14 mL H2/g-COD, respectively, were obtained at an HRT of 6 h. Long-term operation of FBR at 6 h HRT indicated that expanded clay efficiently immobilizes T. thermosaccharolyticum KKU19, for which an HPR of 6.82 ± 0.56 L H2/L day, and an HY of 231.99 ± 19.59 mL H2/g-COD were obtained. Furthermore, the COD removal efficiency of 30% obtained under long-term operation was comparable to that under short-term operation at an HRT of 6 days. Butyric and acetic acids were the main soluble metabolite products, thereby indicating a butyrate–acetate type fermentation. Our findings indicate that expanded clay is an effective support material that contributes to the protection of microbial cells and can be used for long-term operation.

scholarly journals Human Consensus-Oriented Image Captioning

2020 ◽  
Author(s):  
Ziwei Wang ◽  
Zi Huang ◽  
Yadan Luo
Keyword(s):  
Data Quality ◽  
Ground Truth ◽  
Superior Performance ◽  
The Novel ◽  
Image Captioning ◽  
Visual Objects ◽  
Grammatical Errors ◽  
Wrong Identification ◽  
Model Training ◽  
Treat All

Image captioning aims to describe an image with a concise, accurate, and interesting sentence. To build such an automatic neural captioner, the traditional models align the generated words with a number of human-annotated sentences to mimic human-like captions. However, the crowd-sourced annotations inevitably come with data quality issues such as grammatical errors, wrong identification of visual objects and sub-optimal sentence focus. During the model training, existing methods treat all the annotations equally regardless of the data quality. In this work, we explicitly engage human consensus to measure the quality of ground truth captions in advance, and directly encourage the model to learn high quality captions with high priority. Therefore, the proposed consensus-oriented method can accelerate the training process and achieve superior performance with only supervised objective without time-consuming reinforcement learning. The novel consensus loss can be implemented into most of the existing state-of-the-art methods, boosting the BLEU-4 performance by maximum relative 12.47% comparing to the conventional cross-entropy loss. Extensive experiments are conducted on MS-COCO Image Captioning dataset demonstrating the proposed human consensus-oriented training method can significantly improve the training efficiency and model effectiveness.

Synthesis and Structural Systematics of Nitrogen Base Adducts of Group 2 Salts. VII. Some Complexes of Group 2 Metal Halides With Aromatic N,N'-Bidentate Ligands

1996 ◽  
Vol 49 (1) ◽  
pp. 99 ◽  
Author(s):  
BW Skelton ◽  
AF Waters ◽  
AH White
Keyword(s):  
Room Temperature ◽  
The Novel ◽  
Bidentate Ligands ◽  
Nitrogen Base ◽  
One Dimensional ◽  
X Ray ◽  
L System ◽  
L Systems ◽  
Group 2 ◽  
Structural Characterizations

Syntheses and room-temperature single-crystal X-ray structural characterizations are recorded for a number of adducts of Group 2 halides with the aromatic N,N′- bidentate ligands L = 2,2'-bipyridine ( bpy ) and 1,10-phenanthroline ( phen ). One adduct of 1 : 1 MX2/L stoichiometry is recorded: [( bpy )Ca(μ-Br)(4/2)](∞ ׀ ∞) (1) is monoclinic, C 2/c, a l7.102(5), b 9.845(1), c 7.600(2) Ǻ, β 107.65(2)°, Z = 4 f.u .; conventional R on #1472; F ׀ at convergence was 0.057 for No 817 independent 'observed' ( I > 3σ(I)) reflections, the compound being a one-dimensional polymer… CaL (μ-Br)2CaL(μ-Br)2…, with six-coordinate calcium, cis-CaN2(μ-Br)4, on a twofold axis. 1 : 2 MX2/L systems have been described for two types of array: [( bpy )2CaI2] (2), orthorhombic, Pnca, a 16.914(4), b 13.80(1), c 9.290(4) Ǻ, Z = 4 f.u .; R 0.039 for No 1738, is discrete mononuclear, containing cis-CaN4I2 six-coordinate calcium, whereas the barium analogue is an infinite one-dimensional polymer, [( bpy )2Ba(μ-I)(4/2)](∞׀ ∞) (3), triclinic, Pī, a 11.318(2), b 11.078(2), c 9.206(4) Ǻ, α 80.87(2), β 77.52(2), γ 87.53(1)°, Z = 2 f.u .; R 0.032 for No 4154, with eight-coordinate (N2)2Ba(μ-I)4. The perchlorate analogue, [( bpy )2Ba(μ-OClO2O)(4/2)](∞ ׀ ∞) (4), although of similar stoichiometry, has a trans-rather than a cis-linked chain; it is monoclinic, P 21/c, a 6.606(2), b 18.661(7), c 19.440(8) Ǻ, β 109.45(4)°, Z = 4 f.u .; R 0.044 for No 4060, with μ-I replaced by O,O'-ClO4 bridging units and eight-coordinate barium, (N2)2BaO4. The 1 : 3 MX2/L system is represented (as its hemi( bipyridine ) 'solvate') by mononuclear [( bpy )3SrI2].0.5bpy (5), monoclinic, P 21/c, a 20.834(8), b 9.735(4), c 18.460(7) Ǻ, β 114.87(3)°, Z = 4 f.u .; R 0.039 for No 3711, containing eight-coordinate strontium, [(N2)3SrI2]; there is also an isomorphous calcium/ perchlorate analogue [( bpy )3Ca(OClO3)2].0.5bpy (6), a 21.413(6), b 9.813(4), c 18.659(2) Ǻ, β 115.67(2)°, R 0.057 for No 3090, in which unidentate O-ClO4 ligands replace the iodine about the metal atom. A 1 : 4 adduct is obtained with CaI2/phen; ionic [Ca( phen )4] I2 (7), triclinic, Pī , a 14.703(3), b 13.292(3), c 11.38(1) Ǻ, α 92.78(4), β 96.15(4), γ 105.22(2)°, Z = 2 f.u ., R 0.053 for No 3658, contains eight-coordinate Ca(N2)4 arrays, while the novel 1 : 5 adduct [ Ba ( phen )4] I2.MeCN (8) is triclinic, Pī , a 12.170(6), b 13.760(7), c 18 254(8) Ǻ, α 77.05(9), ,β 71.96(4), γ 70.83(9)°, Z = 2 f.u ., R 0.040 for No 4447, containing 10-coordinate barium, [ Ba (N2)5]. A 1 : 4 adduct formed with BaBr2 is [ BrBa( phen )4] Br.MeOH (9), triclinic, Pī , a 17.748(4), b 17.418(2), c 15.535(7) Ǻ, α 91.63(2), β 100.53(3), γ 115.39(1)°, Z = 4 f.u ., R 0.062 for No 4092, containing nine-coordinate barium, [ BrBa (N2)4].

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