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71.
Pannipha Dokamaingam Navadol Laosiripojana Apinan Soottitantawat Suttichai Assabumrungrat 《American Institute of Chemical Engineers》2010,56(6):1639-1650
Mathematical models of direct internal reforming solid oxide fuel cell (DIR‐SOFC) fueled by methane are developed using COMSOL® software. The benefits of inserting Ni‐catalyst rod in the middle of tubular‐SOFC are simulated and compared to conventional DIR‐SOFC. It reveals that DIR‐SOFC with inserted catalyst provides smoother temperature gradient along the system and gains higher power density and electrochemical efficiency with less carbon deposition. Sensitivity analyses are performed. By increasing inlet fuel flow rate, the temperature gradient and power density improve, but less electrical efficiency with higher carbon deposition is predicted. The feed with low inlet steam/carbon ratio enhances good system performances but also results in high potential for carbon formation; this gains great benefit of DIR‐SOFC with inserted catalyst because the rate of carbon deposition is remarkably low. Compared between counter‐ and co‐flow patterns, the latter provides smoother temperature distribution with higher efficiency; thus, it is the better option for practical applications. © 2009 American Institute of Chemical Engineers AIChE J, 2010 相似文献
72.
Eakkapon Promaros Suttichai Assabumrungrat Navadol Laosiripojana Piyasan Praserthdam Tomohiko Tagawa Shigeo Goto 《Korean Journal of Chemical Engineering》2007,24(1):44-50
The carbon dioxide reforming of methane under periodic operation over a commercial Ni/SiO2·MgO catalyst was investigated at two different temperatures, 923 and 1,023 K. According to this operation, pure methane and
carbon dioxide were alternately fed to the catalyst bed where methane cracking and the reverse Boudouard reaction took place,
respectively. Therefore, hydrogen and carbon monoxide products appeared separately in different product streams. The performance
of this operation was compared to that of the steady state operation with simultaneous feed of both carbon dioxide and methane.
At 1,023 K, the methane conversion and hydrogen yield from the periodic operation initially decreased with time on stream
and eventually leveled off at values about half of those obtained in the steady state operation with co-feed of both reactants.
The decreased catalytic activity was due to the accumulation of carbonaceous deposit and loss of metal active sites. However,
a different trend was observed at 923 K. The methane conversion and hydrogen yield were almost constant over the time on stream,
although more carbonaceous deposit was progressively accumulated on the catalyst bed during the reaction course. At this temperature,
the periodic operation offered the equivalent hydrogen yield to the steady state operation. The observed behavior could be
due to the different mechanisms of carbon formation over the catalyst. Finally, it was found that cycle period and cycle split
did not influence the reaction performance within the ranges of this study. 相似文献
73.
Amornchai Arpornwichanop Chantarawadee Wiwittanaporn Suthida Authayanun Suttichai Assabumrungrat 《Korean Journal of Chemical Engineering》2008,25(6):1252-1266
The recovery of dilute acetic acid, which is widely found as a by-product in many chemical and petrochemical industries, becomes
an important issue due to economic and environmental awareness. In general, separation of acetic acid in aqueous solution
by conventional distillation columns is difficult, requiring a column with many stages and high energy consumption. As a result,
the primary concern of the present study is the application of reactive distillation as a potential alternative method to
recover dilute acetic acid. The direct use of dilute acetic acid as reactant for esterification with butanol to produce butyl
acetate in the reactive distillation is investigated. Simulation studies are performed in order to investigate effect of the
concentration of dilute acetic acid and key process parameters on the performance of the reactive distillation in terms of
acetic acid conversion and butyl acetate production. In addition, three alternative control strategies are studied for the
closed loop control of the reactive distillation. The control objective is to maintain the butyl acetate in a bottom product
stream at the desired purity of 99.5 wt%. 相似文献
74.
75.
Amornchai Arpornwichanop Nuttapong Chalermpanchai Yaneeporn Patcharavorachot Suttichai Assabumrungrat Moses Tade 《International Journal of Hydrogen Energy》2009,34(18):7780-7788
A theoretical study of a solid oxide fuel cell (SOFC) fed by ethanol is presented in this study. The previous studies mostly investigated the performance of ethanol-fuelled fuel cells based on a thermodynamic analysis and neglected the presence of actual losses encountered in a real SOFC operation. Therefore, the real performance of an anode-supported SOFC with direct-internal reforming operation is investigated here using a one-dimensional isothermal model coupled with a detailed electrochemical model for computing ohmic, activation, and concentration overpotentials. Effects of design and operating parameters, i.e., anode thickness, temperature, pressure, and degree of ethanol pre-reforming, on fuel cell performance are analyzed. The simulation results show that when SOFC is operated at the standard conditions (V = 0.65 V, T = 1023 K, and P = 1 atm), the average power density of 0.51 W cm−2 is obtained and the activation overpotentials represent a major loss in the fuel cell, followed by the ohmic and concentration losses. An increase in the thickness of anode decreases fuel cell efficiency due to increased anode concentration overpotential. The performance of the anode-supported SOFC fuelled by ethanol can be improved by either increasing temperature, pressure, degree of pre-reforming of ethanol, and steam to ethanol molar ratio or decreasing the anode thickness and fuel flow rate at inlet. It is suggested that the anode thickness and operating conditions should be carefully determined to optimize fuel cell efficiency and fuel utilization. 相似文献
76.
Maximum power point tracking using adaptive fuzzy logic control for grid-connected photovoltaic system 总被引:1,自引:0,他引:1
Nopporn Patcharaprakiti Suttichai Premrudeepreechacharn Yosanai Sriuthaisiriwong 《Renewable Energy》2005,30(11):1693
This paper proposes a method of maximum power point tracking using adaptive fuzzy logic control for grid-connected photovoltaic systems. The system is composed of a boost converter and a single-phase inverter connected to a utility grid. The maximum power point tracking control is based on adaptive fuzzy logic to control a switch of a boost converter. Adaptive fuzzy logic controllers provide attractive features such as fast response, good performance. In addition, adaptive fuzzy logic controllers can also change the fuzzy parameter for improving the control system. The single phase inverter uses predictive current control which provides current with sinusoidal waveform. Therefore, the system is able to deliver energy with low harmonics and high power factor. Both conventional fuzzy logic controller and adaptive fuzzy logic controller are simulated and implemented to evaluate performance. Simulation and experimental results are provided for both controllers under the same atmospheric condition. From the simulation and experimental results, the adaptive fuzzy logic controller can deliver more power than the conventional fuzzy logic controller. 相似文献
77.
N. Khunathorncharoenwong P. Charoensuppanimit S. Assabumrungrat P. Kim-Lohsoontorn 《International Journal of Hydrogen Energy》2021,46(48):24591-24606
The novel methanol production from carbon dioxide (CO2) and hydrogen (H2) called alcohol-assisted process is simulated. Although the alcohol-assisted process allows the reduction in operating temperature and pressure, the subsequent product purification is complicated. Comparative studies between the conventional CO2 hydrogenation and the alcohol-assisted processes are carried out (case I–V). The alcohol-assisted processes present the opportunity of increasing the CO2 conversion per-pass and reducing 25% of the hydrogen consumption, the barriers in the conventional process. However, the product purifications remain challenging due to the azeotrope of methanol and by-products. Energy consumptions decrease in the feed and reaction sections of the alcohol-assisted processes but significant increase in the product purifications. The formation of by-products and the sequence of purification units affect process performance and economics. The obtained results indicate that the product purification and the catalyst development to increase methanol selectivity and produce an easy-separated by-product play key roles in the enhancement of the process feasibility. 相似文献
78.
Thirasak Pairojpiriyakul Worapon Kiatkittipong Suttichai Assabumrungrat Eric Croiset 《International Journal of Hydrogen Energy》2014
Glycerol reforming was investigated under supercritical water conditions (450–575 °C, 250 bar). A feed containing 5 wt.% of glycerol was continuously fed to an empty Inconel 625 reactor. The products of the reaction were separated into gas and liquid phases in a condenser. At a feed rate of 2.15 g/min, the glycerol conversion significantly increased from 0.05 to 0.97 when increasing operating temperature from 450 to 575 °C. Although lowering the feed rate (i.e. increasing the residence time) could considerably improve the conversion, carbon formation became a problem especially at high operating temperatures (550–575 °C). The major gaseous products were hydrogen (approximately 60 mol%), carbon monoxide, carbon dioxide and methane with some traces of ethane, ethylene, propane, and propylene. Various liquid products were detected including acetaldehyde, acetol, methanol, acetic acid, propionaldehyde, allyl alcohol, acetone, acrolein, ethanol, ethylene glycol, and acrylic acid but the major liquid components were acetaldehyde and acetol. With a feed glycerol concentration of 2.5 wt.% and operating temperature of 525 °C, glycerol conversion of 0.91 and H2 yield of 2.86 can be obtained without carbon formation. Finally, it was demonstrated that higher H2 yield with much lower carbon formation was observed in supercritical water reforming (250 bar) compared to conventional steam reforming at 1 bar under similar temperatures. 相似文献