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description Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Takuji Harada; Hirotatsu Watanabe; Yoshiyuki Suzuki; Haruyuki Kamata; Yohsuke Matsushita; Hideyuki Aoki; Takatoshi Miura;Abstract Numerical simulations of combined natural convection–conduction in a droplet of n-dodecane suspended from a thermocouple were carried out, taking into consideration evaporation, and the effect of thermocouple diameter on the evaporation characteristics was investigated. The calculated temperature history of the droplet is in good agreement with experimental results; both show that the rate of heating decreases with increasing thermocouple diameter. The maximum error in temperature due to the thermocouple increases linearly with increasing thermocouple diameter. Thus, in investigations involving a droplet suspended from a thermocouple, it is preferable to use a thermocouple with the smallest possible diameter.
International Journa... arrow_drop_down International Journal of Heat and Mass TransferArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.ijheatmasstransfer.2010.08.021&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 47 citations 47 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert International Journa... arrow_drop_down International Journal of Heat and Mass TransferArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.ijheatmasstransfer.2010.08.021&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type 2017Publisher:The Electrochemical Society Authors: Tsuyoshi Nagasawa; Merika Chanthanumataporn; Katsunori Hanamura; Hirotatsu Watanabe; +1 AuthorsTsuyoshi Nagasawa; Merika Chanthanumataporn; Katsunori Hanamura; Hirotatsu Watanabe; Masaru Kanie;The nickel/yttria-stabilized zirconia (Ni/YSZ) has widely used as an anode for solid oxide fuel cells (SOFCs). The high operation temperature allows an SOFC to operate on a wide range of fuels, including hydrocarbons and coal syngas. Direct internal reforming reactions inside SOFC porous anodes enable the hydrocarbon fuel and steam into H2 and CO. The internal reforming fuel cells eliminate the requirement for a separate fuel reformer, leading to more efficient system. Meanwhile, Ni is also a catalyst for carbon deposition reactions such as methane cracking. The deposited carbon deactivates the Ni catalyst and causes rapid cell degradation. Although the high steam/carbon ratio is able to suppress carbon formation, it lowers the electrical efficiency by steam dilution of the fuel. Thus, an optimum steam/carbon ratio results in high performance of SOFC. This study aims to investigate mechanisms of carbon deposition on Ni/YSZ anode experimentally and numerically. First, the carbon deposition on Ni/YSZ was observed with SEM/EDX. Then, carbon deposition pathways on Ni surface were studied by detailed reaction kinetics. Moreover, the impact of steam carbon ratio on carbon deposition was investigated. An electrolyte-supported button cell was used. The disk-type electrolyte was composed of YSZ (8 mol% Y2O3-stabilized ZrO2). The diameter and thickness of the cell were 20 mm and 300 mm, respectively. To manufacture the anode, a mixture of NiO/YSZ powder, ethyl cellulose, α-terpineol, a dispersant and a plasticizer was prepared and coated on one side of the disk (Ni:YSZ = 50:50 vol%). The disk was dried at 90 oC for 12 h and sintered at a temperature of 1300 oC. The fabricated cell was put into a quartz reactor. The temperature near the cell was measured by K-type thermocouple. The cell was heated in the reactor to 900 oC by an electric furnace. CH4 and Ar were supplied to the cell at 10 and 90 ml/min, respectively. The mixture gas impinged on the cell. During the experiment, H2 concentration in off-gas from the reactor was measured with GC. Before the cell was pulled out from the quartz reactor for ex-situ observation, the gas line was switched from CH4/Ar to Ar, and the reactor was rapidly cooled for reaction quench. Then, the carbon deposition on the cell was performed by SEM-EDX and off-gas analysis. The carbon was supposed to form on Ni surface. Thus, the one-dimensional stagnation flow model in which CH4/Ar flow impinged on the Ni plate like experimental setup was used in the calculation. Catalytic heterogeneous reactions were modeled by elemental step based reaction mechanisms developed by Maier et al. (Top. Catal., 54 (2011) 845-858). The 42 surface reactions involving 12 surface-adsorbed species were used. The transient surface coverage of carbon was calculated, and the carbon formation pathways were computationally studied. As a result, the amount of carbon was increased as time proceeded in the experiment. The amount of deposited carbon measured with the balance corresponded to that estimated from H2 concentration, assuming that the carbon was formed through CH4 decomposition (CH4 → C + 2 H2). It was shown that the mass was well balanced in the experimental system. SEM-EDX analysis showed that carbon was deposited on not YSZ but Ni surface, indicating Ni acted as catalyst for carbon deposition as reported by previous studies. 20 min after CH4/Ar was supplied, the Ni/YSZ layer started to expand. A swelling ratio based on the initial cell thickness became over 100 % after 60 min. SEM observation showed that the porous anode structure was destroyed by the carbon growth. In fact, the recovery of the anode structure was difficult once the anode was expanded even if the carbon was removed by reforming. Calculation showed that the surface coverage of carbon became over 0.9 within 10 sec when CH4/Ar was supplied to Ni substrate at the same condition as the experiment. Carbon was formed on the surface subsequent to CH4 adsorption on Ni surface and dissociation reactions. CH4 adsorption reaction on Ni surface showed a high sensitivity against the carbon formation. Calculation also showed that the carbon was not formed when S/C (steam carbon ratio) was less than 1.0 where the carbon was formed in equilibrium condition, indicating kinetics of surface reaction played an important role in the carbon deposition than equilibrium.
ECS Meeting Abstract... arrow_drop_down ECS Meeting AbstractsArticle . 2017 . Peer-reviewedLicense: IOP Copyright PoliciesData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/ma2017-03/1/248&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 4 citations 4 popularity Average influence Average impulse Average Powered by BIP!
more_vert ECS Meeting Abstract... arrow_drop_down ECS Meeting AbstractsArticle . 2017 . Peer-reviewedLicense: IOP Copyright PoliciesData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/ma2017-03/1/248&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 JapanPublisher:American Chemical Society (ACS) Authors: Hirotatsu Watanabe; Takashi Marumo; Ken Okazaki;doi: 10.1021/ef201702g
In this study, the effect of CO2 reactivity on low NOx combustion by varying CO2 mole fraction in inflow gas was experimentally and numerically investigated. A flat CH4 flame doped with NH3 for fuel N was formed in a reactor allowed secondary gas injection to simulate the fuel-rich region in a low NOx burner. The primary relative O2/CH4 ratio (λprimary) was 0.6 or 0.7, and the total relative O2/CH4 ratio was set to 0.8 by injecting a secondary gas. Measurement showed excited OH radical increased with increasing inlet CO2 mole fraction, and calculation showed that OH radical formation increased with increasing inlet CO2 mole fraction through the CO2 + H → CO + OH. N2 formation provided useful information to discuss low NOx combustion because an increase in the N2 yield indicated low NOx combustion. At λprimary = 0.7, the N2 yield decreased with increasing inlet CO2 mole fraction. Meanwhile, the N2 yield increased with increasing inlet CO2 mole fraction at λprimary = 0.6, regardless of the gas temperature. ...
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1021/ef201702g&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 38 citations 38 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1021/ef201702g&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2018 JapanPublisher:The Electrochemical Society Authors: Hirotatsu Watanabe; Minori Nakanouchi; Katsunori Hanamura;doi: 10.1149/2.0231807jes
A triple phase boundary reaction site was formed in a direct carbon fuel cell (DCFC) when the char wetted by molten carbonate was in contact with the anode. It has been reported that gases such as CO2 covered the anode during discharge, leading to high anode overpotential. In this study, a press-type DCFC was developed to overcome this issue. By pressing the perforated anode on the carbon/carbonate-packed bed, it was expected that the carbon particles would remain in contact with the anode, while the gas products would be released through the perforation due to their buoyancy. As a result, the power output achieved with the press-type DCFC was higher and more stable as compared with the conventional DCFC. The anodic impedance spectra showed that the arc size of the press-type DCFC was much smaller than that of the conventional DCFC. This was particularly noticeable at the low frequencies, indicating the anode resistance caused by the mass transfer processes including the gas products and the contact between the anode and carbon particles to be significantly less in the press-type DCFC.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/2.0231807jes&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/2.0231807jes&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 JapanPublisher:Japan Society of Mechanical Engineers Authors: Yukihiko Okumura; Hirotatsu Watanabe; Ken Okazaki;The purpose of this study is to clarify the fundamental and general features of N2O formation during the combustion of pulverized biomass under low temperature. First, the effect of various important factors, i.e., combustion temperature, volatilization process (i.e., either slow or rapid dispersion), and nitrogen content in biomass on N2O formation were investigated by theoretical analysis. The analysis of the effect of combustion temperature on the formation of nitrous oxide showed that N2O emission level increases with the decrease in combustion temperature, and both N2O and NO levels are strongly dependent on the combustion temperature. In other words, there is a trade-off relationship between the formation of NO and that of N2O. The analysis of the effect of the slow/rapid volatilization process on the formation of nitrous oxide showed that the conversion ratio of biomass-N to N2O increases with the decrease in the dispersion of volatile matter per unit time; it means that biomass-N is effectively converted to N2O during slow volatilization. Further, the gasification reactions between CO2, O2, and C occur simultaneously on the surface of biomass particles during combustion. With respect to the effect of nitrogen content in biomass, the N2O emission level increases with the increase in N-content of the biomass, while the NO emission level remains constant during low-temperature combustion.
TRANSACTIONS OF THE ... arrow_drop_down TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series BArticle . 2013 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1299/kikaib.79.465&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 3 citations 3 popularity Average influence Average impulse Average Powered by BIP!
more_vert TRANSACTIONS OF THE ... arrow_drop_down TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series BArticle . 2013 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1299/kikaib.79.465&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 JapanPublisher:Elsevier BV Authors: Willy Yanto Wijaya; Shunsuke Kawasaki; Hirotatsu Watanabe; Ken Okazaki;Studies on the kinetics of methanol steam reforming (MSR) reaction have been extensively carried out in these past decades. However, in order to get a more thorough understanding of the MSR performance, it is necessary to integrate the reaction kinetics of MSR with the reactor design/operating parameters. This paper presents such works and employs Damkohler number (Da) to conveniently describe the trade-off between kinetics (reaction time scale) and operating parameters (residence time scale) of the MSR system. The correlation of Da and methanol conversion was also experimentally verified. Furthermore, feasibility criterion as a parameter to describe energy gain obtained by MSR reaction over the energy required by absorption heat pump (AHP) system was viewed, and its correlation with Da was investigated. Some results showed that even at various combinations of GHSV and MSR reaction temperature, the Da – methanol conversion empirically have a similar typical curve. On the other hand, for the combined AHP–MSR system, changing the value of Da, either by changing the GHSV or MSR reaction temperature, results in different profiles of feasibility criterion and hydrogen production rate.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apenergy.2012.01.041&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 18 citations 18 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apenergy.2012.01.041&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Authors: Willy Yanto Wijaya; Shunsuke Kawasaki; Hirotatsu Watanabe; Ken Okazaki;This paper presents an evaluation of combined absorption heat pump (AHP) and methanol steam reforming (MSR) system. To measure the effectiveness of this combined system, a feasibility criterion was proposed, which measured the ratio between net energy gain obtained by MSR reaction over energy required by AHP system. By using the proposed feasibility criterion, optimum AHP step number could be determined. Other parameters pertaining to both AHP and MSR system were also determined and calculated. In particular, discussions would focus on the effects of steam–carbon molar ratio (S/C) and gas hourly space velocity (GHSV) of experimental MSR upon feasibility criterion of combined system. It was shown that the decrease of GHSV caused the increase of feasibility criterion up to the AHP step number 3; meanwhile, the increase of S/C resulted in the shifting of feasibility criterion peak from AHP step number 3 to 2.
Energy Conversion an... arrow_drop_down Energy Conversion and ManagementArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.enconman.2010.11.013&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 8 citations 8 popularity Average influence Average impulse Average Powered by BIP!
more_vert Energy Conversion an... arrow_drop_down Energy Conversion and ManagementArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.enconman.2010.11.013&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Hirotatsu Watanabe; Yoshiyuki Suzuki; Takuji Harada; Hideyuki Aoki; Takatoshi Miura;This paper describes a mathematical model for predicting the mass of water vapor generated in micro-explosion. First, a single droplet experiment was carried out. A W/O (water/oil) emulsified fuel droplet suspended by a thermocouple was heated by a halogen spot heater, and micro-explosion was observed using a high-speed video camera. The progress of the coalescence of the dispersed water droplet was observed while droplet was heated, and an aggregated water droplet was formed in the oil layer. Based on the measured micro-explosion characteristics, a mathematical model for predicting water vapor mass generated in micro-explosion was proposed. The size of the aggregated water droplet just before micro-explosion was measured to verify the proposed mathematical model. Under certain assumptions, mass and energy conservation equations were applied to micro-explosion process, and an equation to calculate water vapor mass generated in micro-explosion was derived. The derived equation and some measurement results provide enough information to calculate water vapor mass generated in micro-explosion. The calculated diameter of the water droplet, which changed to vapor in micro-explosion, was compared to that of the aggregated water droplet just before micro-explosion. The calculated results roughly agreed with experimental ones, and the validity of the proposed model was verified.
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2011.04.038&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 23 citations 23 popularity Top 10% influence Top 10% impulse Average Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2011.04.038&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Authors: Hirotatsu Watanabe; Jun-ichiro Yamamoto; Ken Okazaki;Abstract The purpose of this study was to investigate the NO x formation and reduction mechanisms in staged O 2 /CO 2 combustion and in air combustion. A flat CH 4 flame doped with NH 3 for fuel-N was formed over the honeycomb, and NO x formation characteristics were investigated. In addition, chemiluminescence of OH * distribution was measured, and CHEMKIN-PRO was used to investigate the detailed NO x reduction mechanism. In general, the NO x conversion ratio decreases with decreasing primary O 2 /CH 4 ratio, whereas NH 3 and HCN, which are easily converted to NO x in the presence of O 2 , increases rapidly. Therefore, a suitable primary O 2 /CH 4 ratio exists in the staged combustion. Our experiments showed the primary O 2 /CH 4 ratio, which gave the minimum fixed nitrogen compounds in O 2 /CO 2 combustion, was lower than in air combustion. The NO x conversion ratio in O 2 /CO 2 combustion was lower than in air combustion by 40% in suitable staged combustion. This could be explained by high CO 2 concentrations in the O 2 /CO 2 combustion. It was shown that abundant OH radicals were formed in O 2 /CO 2 combustion through the CO 2 + H → CO + OH, experimentally and numerically. OH radicals produced H and O radicals through H 2 + OH → H + H 2 O and O 2 + H → OH + O, because a mass of hydrogen source exists in the CH 4 flame. O and OH radicals formed in the fuel-rich region enhanced the oxidation of NH 3 and HCN. NO x formed by the oxidation of NH 3 and HCN was converted to N 2 because the oxidation occurred in the fuel-rich region where the NO x reduction effect was high. In fact, the oxidation of NH 3 and HCN in the fuel-rich region was preferable to remaining NH 3 and HCN before secondary O 2 injection in the staged combustion. A significant reduction in NO x emission could be achieved by staged combustion in O 2 /CO 2 combustion.
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.combustflame.2010.11.006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 76 citations 76 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.combustflame.2010.11.006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2015 JapanPublisher:American Chemical Society (ACS) Authors: Hirotatsu Watanabe; Akihiro Kimura; Ken Okazaki;This study investigated the impact of ternary carbonate composition (Li2CO3/Na2CO3/K2CO3) on the morphology of the carbon/carbonate slurry and the continuous power generation by direct carbon fuel cells (DCFCs). Carbon/carbonate mixtures were melted to form a slurry at 1073 K. After cooling, the morphology of the solidified slurries was observed at the macro and micro scales. Notable differences were found in the morphology when the carbonate composition was changed. The solidified slurry surface was smooth, with surface carbon particles partly embedded in the carbonate, at Li/Na/K = 12.2/25/62.8 mol %, whereas the slurry surface was irregular, with carbon particles on the surface not embedded in the carbonate at Li/Na/K = 12.2/45/42.8 mol %. This suggested that the carbon particles were well-wetted in the former composition but not in the latter. It was also shown that wetting of the carbon particles was improved by decreasing the mole fraction of Na2CO3, which lowered the surface tension of the molten c...
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1021/acs.energyfuels.5b02224&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 12 citations 12 popularity Top 10% influence Average impulse Top 10% Powered by BIP!
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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description Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Takuji Harada; Hirotatsu Watanabe; Yoshiyuki Suzuki; Haruyuki Kamata; Yohsuke Matsushita; Hideyuki Aoki; Takatoshi Miura;Abstract Numerical simulations of combined natural convection–conduction in a droplet of n-dodecane suspended from a thermocouple were carried out, taking into consideration evaporation, and the effect of thermocouple diameter on the evaporation characteristics was investigated. The calculated temperature history of the droplet is in good agreement with experimental results; both show that the rate of heating decreases with increasing thermocouple diameter. The maximum error in temperature due to the thermocouple increases linearly with increasing thermocouple diameter. Thus, in investigations involving a droplet suspended from a thermocouple, it is preferable to use a thermocouple with the smallest possible diameter.
International Journa... arrow_drop_down International Journal of Heat and Mass TransferArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.ijheatmasstransfer.2010.08.021&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 47 citations 47 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert International Journa... arrow_drop_down International Journal of Heat and Mass TransferArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.ijheatmasstransfer.2010.08.021&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type 2017Publisher:The Electrochemical Society Authors: Tsuyoshi Nagasawa; Merika Chanthanumataporn; Katsunori Hanamura; Hirotatsu Watanabe; +1 AuthorsTsuyoshi Nagasawa; Merika Chanthanumataporn; Katsunori Hanamura; Hirotatsu Watanabe; Masaru Kanie;The nickel/yttria-stabilized zirconia (Ni/YSZ) has widely used as an anode for solid oxide fuel cells (SOFCs). The high operation temperature allows an SOFC to operate on a wide range of fuels, including hydrocarbons and coal syngas. Direct internal reforming reactions inside SOFC porous anodes enable the hydrocarbon fuel and steam into H2 and CO. The internal reforming fuel cells eliminate the requirement for a separate fuel reformer, leading to more efficient system. Meanwhile, Ni is also a catalyst for carbon deposition reactions such as methane cracking. The deposited carbon deactivates the Ni catalyst and causes rapid cell degradation. Although the high steam/carbon ratio is able to suppress carbon formation, it lowers the electrical efficiency by steam dilution of the fuel. Thus, an optimum steam/carbon ratio results in high performance of SOFC. This study aims to investigate mechanisms of carbon deposition on Ni/YSZ anode experimentally and numerically. First, the carbon deposition on Ni/YSZ was observed with SEM/EDX. Then, carbon deposition pathways on Ni surface were studied by detailed reaction kinetics. Moreover, the impact of steam carbon ratio on carbon deposition was investigated. An electrolyte-supported button cell was used. The disk-type electrolyte was composed of YSZ (8 mol% Y2O3-stabilized ZrO2). The diameter and thickness of the cell were 20 mm and 300 mm, respectively. To manufacture the anode, a mixture of NiO/YSZ powder, ethyl cellulose, α-terpineol, a dispersant and a plasticizer was prepared and coated on one side of the disk (Ni:YSZ = 50:50 vol%). The disk was dried at 90 oC for 12 h and sintered at a temperature of 1300 oC. The fabricated cell was put into a quartz reactor. The temperature near the cell was measured by K-type thermocouple. The cell was heated in the reactor to 900 oC by an electric furnace. CH4 and Ar were supplied to the cell at 10 and 90 ml/min, respectively. The mixture gas impinged on the cell. During the experiment, H2 concentration in off-gas from the reactor was measured with GC. Before the cell was pulled out from the quartz reactor for ex-situ observation, the gas line was switched from CH4/Ar to Ar, and the reactor was rapidly cooled for reaction quench. Then, the carbon deposition on the cell was performed by SEM-EDX and off-gas analysis. The carbon was supposed to form on Ni surface. Thus, the one-dimensional stagnation flow model in which CH4/Ar flow impinged on the Ni plate like experimental setup was used in the calculation. Catalytic heterogeneous reactions were modeled by elemental step based reaction mechanisms developed by Maier et al. (Top. Catal., 54 (2011) 845-858). The 42 surface reactions involving 12 surface-adsorbed species were used. The transient surface coverage of carbon was calculated, and the carbon formation pathways were computationally studied. As a result, the amount of carbon was increased as time proceeded in the experiment. The amount of deposited carbon measured with the balance corresponded to that estimated from H2 concentration, assuming that the carbon was formed through CH4 decomposition (CH4 → C + 2 H2). It was shown that the mass was well balanced in the experimental system. SEM-EDX analysis showed that carbon was deposited on not YSZ but Ni surface, indicating Ni acted as catalyst for carbon deposition as reported by previous studies. 20 min after CH4/Ar was supplied, the Ni/YSZ layer started to expand. A swelling ratio based on the initial cell thickness became over 100 % after 60 min. SEM observation showed that the porous anode structure was destroyed by the carbon growth. In fact, the recovery of the anode structure was difficult once the anode was expanded even if the carbon was removed by reforming. Calculation showed that the surface coverage of carbon became over 0.9 within 10 sec when CH4/Ar was supplied to Ni substrate at the same condition as the experiment. Carbon was formed on the surface subsequent to CH4 adsorption on Ni surface and dissociation reactions. CH4 adsorption reaction on Ni surface showed a high sensitivity against the carbon formation. Calculation also showed that the carbon was not formed when S/C (steam carbon ratio) was less than 1.0 where the carbon was formed in equilibrium condition, indicating kinetics of surface reaction played an important role in the carbon deposition than equilibrium.
ECS Meeting Abstract... arrow_drop_down ECS Meeting AbstractsArticle . 2017 . Peer-reviewedLicense: IOP Copyright PoliciesData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/ma2017-03/1/248&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 4 citations 4 popularity Average influence Average impulse Average Powered by BIP!
more_vert ECS Meeting Abstract... arrow_drop_down ECS Meeting AbstractsArticle . 2017 . Peer-reviewedLicense: IOP Copyright PoliciesData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/ma2017-03/1/248&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 JapanPublisher:American Chemical Society (ACS) Authors: Hirotatsu Watanabe; Takashi Marumo; Ken Okazaki;doi: 10.1021/ef201702g
In this study, the effect of CO2 reactivity on low NOx combustion by varying CO2 mole fraction in inflow gas was experimentally and numerically investigated. A flat CH4 flame doped with NH3 for fuel N was formed in a reactor allowed secondary gas injection to simulate the fuel-rich region in a low NOx burner. The primary relative O2/CH4 ratio (λprimary) was 0.6 or 0.7, and the total relative O2/CH4 ratio was set to 0.8 by injecting a secondary gas. Measurement showed excited OH radical increased with increasing inlet CO2 mole fraction, and calculation showed that OH radical formation increased with increasing inlet CO2 mole fraction through the CO2 + H → CO + OH. N2 formation provided useful information to discuss low NOx combustion because an increase in the N2 yield indicated low NOx combustion. At λprimary = 0.7, the N2 yield decreased with increasing inlet CO2 mole fraction. Meanwhile, the N2 yield increased with increasing inlet CO2 mole fraction at λprimary = 0.6, regardless of the gas temperature. ...
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1021/ef201702g&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 38 citations 38 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1021/ef201702g&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2018 JapanPublisher:The Electrochemical Society Authors: Hirotatsu Watanabe; Minori Nakanouchi; Katsunori Hanamura;doi: 10.1149/2.0231807jes
A triple phase boundary reaction site was formed in a direct carbon fuel cell (DCFC) when the char wetted by molten carbonate was in contact with the anode. It has been reported that gases such as CO2 covered the anode during discharge, leading to high anode overpotential. In this study, a press-type DCFC was developed to overcome this issue. By pressing the perforated anode on the carbon/carbonate-packed bed, it was expected that the carbon particles would remain in contact with the anode, while the gas products would be released through the perforation due to their buoyancy. As a result, the power output achieved with the press-type DCFC was higher and more stable as compared with the conventional DCFC. The anodic impedance spectra showed that the arc size of the press-type DCFC was much smaller than that of the conventional DCFC. This was particularly noticeable at the low frequencies, indicating the anode resistance caused by the mass transfer processes including the gas products and the contact between the anode and carbon particles to be significantly less in the press-type DCFC.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/2.0231807jes&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1149/2.0231807jes&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 JapanPublisher:Japan Society of Mechanical Engineers Authors: Yukihiko Okumura; Hirotatsu Watanabe; Ken Okazaki;The purpose of this study is to clarify the fundamental and general features of N2O formation during the combustion of pulverized biomass under low temperature. First, the effect of various important factors, i.e., combustion temperature, volatilization process (i.e., either slow or rapid dispersion), and nitrogen content in biomass on N2O formation were investigated by theoretical analysis. The analysis of the effect of combustion temperature on the formation of nitrous oxide showed that N2O emission level increases with the decrease in combustion temperature, and both N2O and NO levels are strongly dependent on the combustion temperature. In other words, there is a trade-off relationship between the formation of NO and that of N2O. The analysis of the effect of the slow/rapid volatilization process on the formation of nitrous oxide showed that the conversion ratio of biomass-N to N2O increases with the decrease in the dispersion of volatile matter per unit time; it means that biomass-N is effectively converted to N2O during slow volatilization. Further, the gasification reactions between CO2, O2, and C occur simultaneously on the surface of biomass particles during combustion. With respect to the effect of nitrogen content in biomass, the N2O emission level increases with the increase in N-content of the biomass, while the NO emission level remains constant during low-temperature combustion.
TRANSACTIONS OF THE ... arrow_drop_down TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series BArticle . 2013 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1299/kikaib.79.465&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 3 citations 3 popularity Average influence Average impulse Average Powered by BIP!
more_vert TRANSACTIONS OF THE ... arrow_drop_down TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series BArticle . 2013 . Peer-reviewedData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1299/kikaib.79.465&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2012 JapanPublisher:Elsevier BV Authors: Willy Yanto Wijaya; Shunsuke Kawasaki; Hirotatsu Watanabe; Ken Okazaki;Studies on the kinetics of methanol steam reforming (MSR) reaction have been extensively carried out in these past decades. However, in order to get a more thorough understanding of the MSR performance, it is necessary to integrate the reaction kinetics of MSR with the reactor design/operating parameters. This paper presents such works and employs Damkohler number (Da) to conveniently describe the trade-off between kinetics (reaction time scale) and operating parameters (residence time scale) of the MSR system. The correlation of Da and methanol conversion was also experimentally verified. Furthermore, feasibility criterion as a parameter to describe energy gain obtained by MSR reaction over the energy required by absorption heat pump (AHP) system was viewed, and its correlation with Da was investigated. Some results showed that even at various combinations of GHSV and MSR reaction temperature, the Da – methanol conversion empirically have a similar typical curve. On the other hand, for the combined AHP–MSR system, changing the value of Da, either by changing the GHSV or MSR reaction temperature, results in different profiles of feasibility criterion and hydrogen production rate.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apenergy.2012.01.041&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 18 citations 18 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.apenergy.2012.01.041&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Authors: Willy Yanto Wijaya; Shunsuke Kawasaki; Hirotatsu Watanabe; Ken Okazaki;This paper presents an evaluation of combined absorption heat pump (AHP) and methanol steam reforming (MSR) system. To measure the effectiveness of this combined system, a feasibility criterion was proposed, which measured the ratio between net energy gain obtained by MSR reaction over energy required by AHP system. By using the proposed feasibility criterion, optimum AHP step number could be determined. Other parameters pertaining to both AHP and MSR system were also determined and calculated. In particular, discussions would focus on the effects of steam–carbon molar ratio (S/C) and gas hourly space velocity (GHSV) of experimental MSR upon feasibility criterion of combined system. It was shown that the decrease of GHSV caused the increase of feasibility criterion up to the AHP step number 3; meanwhile, the increase of S/C resulted in the shifting of feasibility criterion peak from AHP step number 3 to 2.
Energy Conversion an... arrow_drop_down Energy Conversion and ManagementArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.enconman.2010.11.013&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 8 citations 8 popularity Average influence Average impulse Average Powered by BIP!
more_vert Energy Conversion an... arrow_drop_down Energy Conversion and ManagementArticle . 2011 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.enconman.2010.11.013&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Hirotatsu Watanabe; Yoshiyuki Suzuki; Takuji Harada; Hideyuki Aoki; Takatoshi Miura;This paper describes a mathematical model for predicting the mass of water vapor generated in micro-explosion. First, a single droplet experiment was carried out. A W/O (water/oil) emulsified fuel droplet suspended by a thermocouple was heated by a halogen spot heater, and micro-explosion was observed using a high-speed video camera. The progress of the coalescence of the dispersed water droplet was observed while droplet was heated, and an aggregated water droplet was formed in the oil layer. Based on the measured micro-explosion characteristics, a mathematical model for predicting water vapor mass generated in micro-explosion was proposed. The size of the aggregated water droplet just before micro-explosion was measured to verify the proposed mathematical model. Under certain assumptions, mass and energy conservation equations were applied to micro-explosion process, and an equation to calculate water vapor mass generated in micro-explosion was derived. The derived equation and some measurement results provide enough information to calculate water vapor mass generated in micro-explosion. The calculated diameter of the water droplet, which changed to vapor in micro-explosion, was compared to that of the aggregated water droplet just before micro-explosion. The calculated results roughly agreed with experimental ones, and the validity of the proposed model was verified.
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2011.04.038&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 23 citations 23 popularity Top 10% influence Top 10% impulse Average Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.energy.2011.04.038&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2011 JapanPublisher:Elsevier BV Authors: Hirotatsu Watanabe; Jun-ichiro Yamamoto; Ken Okazaki;Abstract The purpose of this study was to investigate the NO x formation and reduction mechanisms in staged O 2 /CO 2 combustion and in air combustion. A flat CH 4 flame doped with NH 3 for fuel-N was formed over the honeycomb, and NO x formation characteristics were investigated. In addition, chemiluminescence of OH * distribution was measured, and CHEMKIN-PRO was used to investigate the detailed NO x reduction mechanism. In general, the NO x conversion ratio decreases with decreasing primary O 2 /CH 4 ratio, whereas NH 3 and HCN, which are easily converted to NO x in the presence of O 2 , increases rapidly. Therefore, a suitable primary O 2 /CH 4 ratio exists in the staged combustion. Our experiments showed the primary O 2 /CH 4 ratio, which gave the minimum fixed nitrogen compounds in O 2 /CO 2 combustion, was lower than in air combustion. The NO x conversion ratio in O 2 /CO 2 combustion was lower than in air combustion by 40% in suitable staged combustion. This could be explained by high CO 2 concentrations in the O 2 /CO 2 combustion. It was shown that abundant OH radicals were formed in O 2 /CO 2 combustion through the CO 2 + H → CO + OH, experimentally and numerically. OH radicals produced H and O radicals through H 2 + OH → H + H 2 O and O 2 + H → OH + O, because a mass of hydrogen source exists in the CH 4 flame. O and OH radicals formed in the fuel-rich region enhanced the oxidation of NH 3 and HCN. NO x formed by the oxidation of NH 3 and HCN was converted to N 2 because the oxidation occurred in the fuel-rich region where the NO x reduction effect was high. In fact, the oxidation of NH 3 and HCN in the fuel-rich region was preferable to remaining NH 3 and HCN before secondary O 2 injection in the staged combustion. A significant reduction in NO x emission could be achieved by staged combustion in O 2 /CO 2 combustion.
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.combustflame.2010.11.006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 76 citations 76 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.combustflame.2010.11.006&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Journal 2015 JapanPublisher:American Chemical Society (ACS) Authors: Hirotatsu Watanabe; Akihiro Kimura; Ken Okazaki;This study investigated the impact of ternary carbonate composition (Li2CO3/Na2CO3/K2CO3) on the morphology of the carbon/carbonate slurry and the continuous power generation by direct carbon fuel cells (DCFCs). Carbon/carbonate mixtures were melted to form a slurry at 1073 K. After cooling, the morphology of the solidified slurries was observed at the macro and micro scales. Notable differences were found in the morphology when the carbonate composition was changed. The solidified slurry surface was smooth, with surface carbon particles partly embedded in the carbonate, at Li/Na/K = 12.2/25/62.8 mol %, whereas the slurry surface was irregular, with carbon particles on the surface not embedded in the carbonate at Li/Na/K = 12.2/45/42.8 mol %. This suggested that the carbon particles were well-wetted in the former composition but not in the latter. It was also shown that wetting of the carbon particles was improved by decreasing the mole fraction of Na2CO3, which lowered the surface tension of the molten c...
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You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1021/acs.energyfuels.5b02224&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 12 citations 12 popularity Top 10% influence Average impulse Top 10% Powered by BIP!
more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1021/acs.energyfuels.5b02224&type=result"></script>'); --> </script>
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