scholarly journals Variation of the Number of Heat Sources in Methane Dry Reforming: A Computational Fluid Dynamics Study

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Sunggeun Lee ◽  
Hankwon Lim
Keyword(s):  
Heat Source ◽  
Molten Salt ◽  
Flow Rate ◽  
Methane Conversion ◽  
Tubular Reactor ◽  
Dry Reforming ◽  
Hydrogen Yield ◽  
Hydrogen Flow Rate ◽  
Hydrogen Flow ◽  
Conversion Performance

To overcome the weak point of the gas type heating (failure in heating uniformly and persistently), liquid type molten salt as a concentration of solar energy was considered as a heat source for dry reforming. This high-temperature molten salt flowing through the center of the tubular reactor supplies necessary heat. The dependence on the number of heat source of the hydrogen production was investigated under the assumption of the fixed volume of the catalyst bed. By changing these numbers, we numerically investigated the methane conversion and hydrogen flow rate to find the best performance. The results showed that the methane conversion performance and hydrogen flow rate improved in proportion to the number of heating tubes. For the one heat source, the reactor surrounded by a heat source rather than that located in the center is the best in terms of hydrogen yield. In addition, this study considered the case in which the system is divided into several smaller reactors of equal sizes and a constant amount of catalyst. In these reactors, we saw that the methane conversion and hydrogen flow rate were reduced. The results indicate that the installation of as many heating tubes as possible is preferable.

Pyrolysis and Steam Gasification of Paper and Evaluation of Paper Char Kinetics

2009 ◽  
Author(s):  
Islam Ahmed ◽  
Ashwani K. Gupta
Keyword(s):  
Flow Rate ◽  
Steam Gasification ◽  
Energy Yield ◽  
Hydrogen Yield ◽  
Hydrogen Flow Rate ◽  
Hydrogen Flow ◽  
Char Gasification ◽  
Gasification Process ◽  
Reactor Temperature ◽  
Partial Overlap

Main characteristics of gaseous yield from steam gasification have been investigated experimentally. Results of steam gasification have been compared to that of pyrolysis. The temperature range investigated were 600 to 1000°C in steps of 100°C. Results have also been obtained under pyrolysis conditions at same temperatures. For steam gasification runs, steam flow rate was kept constant at 8.0 gr./Min.. Investigated characteristics were evolution of syngas flow rate with time, hydrogen flow rate, chemical composition of syngas, energy yield and apparent thermal efficiency. Residuals from both processes were quantified and compared as well. Material destruction, hydrogen yield and energy yield is better with gasification as compared to pyrolysis. This advantage of the gasification process is attributed mainly to char gasification process. Char gasification is found to be more sensitive to the reactor temperature than pyrolysis. Pyrolysis can start at low temperatures of 400 °C; however char gasification starts at 700 °C. A partial overlap between gasification and pyrolysis exists and is presented here. This partial overlap increases with increase in temperature. As an example, at reactor temperature 800 °C this overlap represents around 27% of the char gasification process and almost 95% at reactor temperature 1000°C.

Amorphous-to-nanocrystalline transition in silicon thin films by hydrogen diluted silane using PE-CVD method

2020 ◽  
Vol 13 ◽  
Author(s):  
Ashok Jadhavar ◽  
Vidya Doiphode ◽  
Ajinkya Bhorde ◽  
Yogesh Hase ◽  
Pratibha Shinde ◽  
...  
Keyword(s):  
Flow Rate ◽  
Volume Fraction ◽  
Defect Density ◽  
Hydrogen Flow Rate ◽  
Spectroscopy Analysis ◽  
Deposition Parameter ◽  
Hydrogen Flow ◽  
Cvd Method ◽  
Silicon Thin Films ◽  
Increasing Trend

: Herein, we report effect of variation of hydrogen flow rate on properties of Si:H films synthesized using PE-CVD method. Raman spectroscopy analysis show increase in crystalline volume fraction and crystallite size implying that hydrogen flow in PECVD promote the growth of crystallinity in nc-Si:H films with an expense of reduction in deposition rate. FTIR spectroscopy analysis indicates that hydrogen content in the film increases with increase in hydrogen flow rate and hydrogen is predominantly incorporated in Si-H2 and (Si-H2)n bonding configuration. The optical band gap determined using E04 method and Tauc method (ETauc) show increasing trend with increase in hydrogen flow rate and E04 is found higher than ETauc over the entire range of hydrogen flow rate studied. We also found that the defect density and Urbach energy also increases with increase in hydrogen flow rate. Photosensitivity (Photo /Dark) decreases from  103 to  1 when hydrogen flow rate increased from 30 sccm to 100 sccm and can attributed to amorphous-to-nanocrystallization transition in Si:H films. The results obtained from the present study demonstrated that hydrogen flow rate is an important deposition parameter in PE-CVD to synthesize nc-Si:H films.

scholarly journals Sliding Mode Control for Stabilizing of Boost Converter in a Solid Oxide Fuel Cell

2013 ◽  
Vol 13 (4) ◽  
pp. 139-147 ◽  
Author(s):  
Junsheng Jiao
Keyword(s):  
Fuel Cell ◽  
Sliding Mode Control ◽  
Flow Rate ◽  
Output Voltage ◽  
Sliding Mode ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Hydrogen Flow Rate ◽  
Dc Voltage ◽  
Hydrogen Flow

Abstract The output voltage of Solid Oxide Fuel Cell (SOFC) is usually changed with the temperature and hydrogen flow rate. Since the fuel cell can generate a wide range of voltages and currents at the terminals, as a consequence, a constant DC voltage and function cannot be maintained by itself as a DC voltage power supply source. To solve this problem, a simple SOFC electrochemical model is introduced to control the output voltage. The Sliding Mode Control (SMC) is used to control the output voltage of the DC-DC converter for maintaining the constant DC voltage when the temperature and hydrogen flow rate are changed. By the simulation results it can be seen that the SMC technique has improved the transient response and reduced the steady state error of DC voltage.

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>

Disilane addition versus silane-hydrogen flow rate effect on the PECVD of silicon thin films

2016 ◽  
Vol 34 (6) ◽  
pp. 061307
Author(s):  
Panagiotis Dimitrakellis ◽  
Eleftherios Amanatides ◽  
Dimitrios Mataras ◽  
Angelos G. Kalampounias ◽  
Nikolaos Spiliopoulos ◽  
...  
Keyword(s):  
Thin Films ◽  
Flow Rate ◽  
Rate Effect ◽  
Hydrogen Flow Rate ◽  
Hydrogen Flow ◽  
Silicon Thin Films ◽  
Flow Rate Effect
Sign in / Sign up

Export Citation Format

Share Document