The Experts below are selected from a list of 10374 Experts worldwide ranked by ideXlab platform
Jianlu Zhu - One of the best experts on this subject based on the ideXlab platform.
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experiment and dynamic simulation study on propane pre cooling double nitrogen expander liquefaction process for medium pilot lng plant
Applied Thermal Engineering, 2020Co-Authors: Jianlu Zhu, Wei Zhang, Shengna Liu, Miaoe Liu, I XieAbstract:Abstract In the field of LNG simulation study, most optimization studies have concentrated on the LNG processes at steady-state simulation, and only a few studies have reported the dynamic simulation of the LNG process, which is closer to actual operating conditions. The main purpose of this study was to design a dynamic model of propane pre-cooling double nitrogen-expander LNG process based on an actual LNG plant, to investigate the dynamic behavior of this process, which had been considered suitable for FLNG process in previous studies. Furthermore, this is one of the first studies to verify the dynamic simulation of this process through the actual operation of an LNG plant. First, the dynamic models of the main equipment used in this process were developed. Second, a dynamic simulation of this process was performed, and the dynamic behaviour was investigated. Finally, to verify the accuracy of the dynamic simulation, different types of dynamic conditions were added to the simulation to investigate the behaviour of the process, including disturbances in the Feed Gas Flow rate and shutting down of the propane system. Further, the dynamic responses and average errors between the experimental and simulated values were obtained and discussed. The results indicated that the two-stream heat exchange model can be used to replace the multi-stream heat exchange model for dynamic simulation, with the average error of dynamic simulation being under 10%, the control system can resolve the problem of excess cooling capacity and make the entire system run stably in the case of Feed Gas Flow rate disturbance, the whole system returns to stability within 100 min in the case of the propane system shutdown. The results can provide feasible prediction and verification methods for the construction of large experimental and liquefaction production devices in the future.
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Experiment on adaptability of Feed Gas Flow rate and sea conditions on FLNG spiral wound heat exchanger
International Journal of Heat and Mass Transfer, 2019Co-Authors: Jianlu Zhu, Chongzheng Sun, Shan WeiguangAbstract:Abstract As one of the core equipment of floating liquid natural Gas (FLNG), the spiral wound heat exchanger (SWHE) will be affected by Feed Gas Flow and sea conditions, which will lead to more complex Flow and heat transfer process inside the heat exchanger. In this paper, the experimental device of SWHE based on dual mixed refrigeration (DMR) liquefaction process is built to test the adaptability of Feed Gas Flow and sea conditions on SWHE. Meanwhile, a multi-phase four-stream code for liquid natural Gas (LNG) SWHE is developed. The following conclusions are obtained: (1) the parallel heat transfer calculation program can predict the change of the heat transfer coefficient and the temperature inside the heat exchanger well. (2) The temperature decreasing rate of Feed Gas inside SWHE decreases gradually. When the Feed Gas is liquefied completely, the temperature decreasing rate increases gradually. (3) The heat transfer performance of SWHE is greatly affected under sea conditions.
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Experimental research on the adaptability of liquid natural Gas spiral wound heat exchanger in dual mixed refrigeration liquefaction process
Experimental Thermal and Fluid Science, 2018Co-Authors: Chongzheng Sun, Jianlu Zhu, Hui Han, Shaowei WangAbstract:Abstract As the key equipment of natural Gas liquefaction process, the performance of spiral wound heat exchanger (SWHE) influences operating costs and reliability of the whole system. In order to investigate the adaptability of LNG SWHE in dual mixed refrigeration (DMR) liquefaction process, an experimental device using DMR liquefaction process and a multi-phase multi-stream thermal model for SWHE are both constructed. The variations of Feed Gas Flow rate are selected as disturbances to test the dynamic responses of the LNG SWHE. And the results show that when the Feed Gas mass Flow rate decreases to 0 kg h −1 , slug Flow may occur in the outlet pipeline of mixed refrigerant in shell-side. And during the cooling process of Feed Gas in SWHE, two critical values (−80 and −106 °C) were both obtained. In addition, with an adequate mass Flow rate of mixed refrigerant, the LNG SWHE in DMR liquefaction process could overcome some disturbances and can be operated at a stable state.
Ivar E. Reimanis - One of the best experts on this subject based on the ideXlab platform.
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Measurement and Characterization of a High-Temperature, Coke-Resistant Bi-functional Ni/BZY15 Water-Gas-Shift Catalyst Under Steam-Reforming Conditions
Catalysis Letters, 2018Co-Authors: Dylan M. Jennings, Canan Karakaya, Chuancheng Duan, Ryan O’hayre, Gregory S. Jackson, Ivar E. ReimanisAbstract:This paper characterizes the bi-functional behavior of a unique, nano-dispersed Ni/BZY15 water-Gas-shift catalyst under steam-reforming conditions. The catalyst is highly active above 500 $$^\circ$$ ∘ C and has been found to be exceptionally stable in a hydrocarbon steam reforming environment. The performance can be attributed to two features: (1) well dispersed, nano-sized Ni particles with high surface area, and (2) the ability of the redox-active BZY15 support to remove carbon from the Ni. The bi-functionality is demonstrated through a comparison of WGS activity with BZY15 alone and with a traditional $$\text {Al}_2\text {O}_3$$ Al 2 O 3 support. The WGS activity is measured under a range of operating temperatures, steam-to-carbon ratios, and Feed-Gas Flow rates. A series of elementary reaction steps are proposed to explain the bi-functionality and to provide a basis for development of a detailed reaction mechanism. Graphical Abstract
In-sik Nam - One of the best experts on this subject based on the ideXlab platform.
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Nonthermal Plasma-Enhanced Catalytic Removal of Nitrogen Oxides over V2O5/TiO2 and Cr2O3/TiO2
Industrial & Engineering Chemistry Research, 2003Co-Authors: Young Sun Mok, Dong Jun Koh, Kyong Tae Kim, In-sik NamAbstract:A nonthermal plasma process (dielectric-packed bed reactor) was combined with catalyst to remove nitrogen oxides (NOx). Two different honeycomb catalysts such as V2O5/TiO2 and Cr2O3/TiO2 were compared with respect to the removal characteristic of NOx. The effect of oxygen content, water vapor, Feed Gas Flow rate, reaction temperature, and initial concentration on the removal of NOx was examined. The plasma discharge was found to largely enhance the removal of NOx on the catalyst. Without plasma discharge, V2O5/TiO2 was superior to Cr2O3/TiO2 in terms of NOx removal activity. However, the degree of enhancement in NOx removal as a result of plasma discharge was similar for each system. Cr2O3/TiO2 catalyst reduced NO2 to both NO and N2 while the reduction of NO2 back to NO was not significant on V2O5/TiO2 catalyst. The combined system of the nonthermal plasma with V2O5/TiO2 catalyst removed nearly 90% of NOx at 150 °C that is a relatively low temperature, compared to the typical temperature window of NOx red...
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Oxidation of volatile organic compounds by using a microwave-induced plasma process
Korean Journal of Chemical Engineering, 2003Co-Authors: Young Sun Mok, Ho-chul Kang, Moo Hyun Cho, In-sik NamAbstract:A microwave plasma system using a 2.45 GHz magnetron was applied to the decomposition of volatile organic compounds such as toluene and trichloroethylene. Designed for producing plasma at atmospheric pressure, this microwave plasma system consists of a magnetron detached from a household microwave oven, a directional coupler, a three-stub tuner, a tapered waveguide, and plasma flame section where a quartz tube with a nozzle is located. In this system, the organic compounds can be decomposed by thermal incineration as well as by reactions with various active species formed during plasma discharge. The effect of Feed Gas Flow rate on the decomposition was significant due to the decrease in the Gas temperature, but the initial concentration in the range of 210-2,100 ppm did not largely affect the decomposition efficiency. The principal byproduct was nitrogen oxides because this system was operated at high temperature. To improve the decomposition of the organic compounds, argon was used as a plasma-assisting Gas, together with the air-like Feed Gas mixture. Large enhancement in the decomposition efficiency was achieved by the use of argon.
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Modeling of pulsed corona discharge process for the removal of nitric oxide and sulfur dioxide
Chemical Engineering Journal, 2002Co-Authors: Young Sun Mok, In-sik NamAbstract:Abstract A positive pulsed corona discharge process was applied to the removal of sulfur dioxide and nitric oxide from a simulated flue Gas stream, and a mathematical model was proposed to describe this process theoretically. The proposed model takes into account generation of radicals by pulsed corona discharge, followed by radical utilization for the removal of the pollutants. Radicals such as O, OH, N, H, etc. may be concerned in the removal of the pollutants. Their concentrations were derived by considering direct electron impact on the dissociation of Gaseous molecules (O 2 , N 2 , H 2 O) and subsequent excitation transfer reactions of excited oxygen atoms to produce O and OH radicals. The effects of various operating parameters such as Feed Gas Flow rate, initial concentration, oxygen content, humidity, peak voltage and pulse repetition rate on the removal were examined. So as to establish the validity of the model, the calculated results were compared with the experimental data. Although some discrepancy between the calculated and experimental results was observed at high pulse repetition rate, the proposed model was found to properly predict the experimental data on the whole.
Dylan M. Jennings - One of the best experts on this subject based on the ideXlab platform.
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Measurement and Characterization of a High-Temperature, Coke-Resistant Bi-functional Ni/BZY15 Water-Gas-Shift Catalyst Under Steam-Reforming Conditions
Catalysis Letters, 2018Co-Authors: Dylan M. Jennings, Canan Karakaya, Chuancheng Duan, Ryan O’hayre, Gregory S. Jackson, Ivar E. ReimanisAbstract:This paper characterizes the bi-functional behavior of a unique, nano-dispersed Ni/BZY15 water-Gas-shift catalyst under steam-reforming conditions. The catalyst is highly active above 500 $$^\circ$$ ∘ C and has been found to be exceptionally stable in a hydrocarbon steam reforming environment. The performance can be attributed to two features: (1) well dispersed, nano-sized Ni particles with high surface area, and (2) the ability of the redox-active BZY15 support to remove carbon from the Ni. The bi-functionality is demonstrated through a comparison of WGS activity with BZY15 alone and with a traditional $$\text {Al}_2\text {O}_3$$ Al 2 O 3 support. The WGS activity is measured under a range of operating temperatures, steam-to-carbon ratios, and Feed-Gas Flow rates. A series of elementary reaction steps are proposed to explain the bi-functionality and to provide a basis for development of a detailed reaction mechanism. Graphical Abstract
Young Sun Mok - One of the best experts on this subject based on the ideXlab platform.
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Destruction of Chlorodifluoromethane (CHF2Cl) by Using Dielectric Barrier Discharge Plasma
IEEE Transactions on Plasma Science, 2009Co-Authors: Young Sun Mok, Sang-baek Lee, Myung Shik ChangAbstract:The destruction of chlorodifluoromethane (CHF 2 Cl) was studied in a nonthermal atmospheric pressure plasma reactor with a perforated dielectric barrier, which is capable of producing intense streamers without significant pressure drop across the reactor. The performance of the dielectric barrier discharge reactor was evaluated with the parameters including oxygen content, input power, Feed-Gas Flow rate, and initial CHF 2 Cl concentration. It was found that the reactive species from N 2 mainly contributed to the destruction of CHF 2 Cl rather than those from oxygen and that the destruction efficiency largely decreased as the oxygen content increased. The change in the initial concentration did not nearly affect the destruction efficiency, which can partly be explained by the secondary destruction mechanism. The principle byproducts were identified using Fourier transform infrared spectroscopy, and chemical mechanisms were proposed for the destruction processes. According to the proposed mechanisms, COF 2 was found to act as the key intermediate destruction product to convert CHF 2 Cl into CO 2 and CO.
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Reduction of nitrogen oxides from simulated exhaust Gas by using plasma–catalytic process
Fuel Processing Technology, 2004Co-Authors: Young Sun Mok, Dong Jun Koh, Dong Nam Shin, Kyong Tae KimAbstract:Abstract Removal of nitrogen oxides (NO x ) using a nonthermal plasma reactor (dielectric-packed bed reactor) combined with monolith V 2 O 5 /TiO 2 catalyst was investigated. The effect of initial NO x concentration, Feed Gas Flow rate (space velocity), humidity, and reaction temperature on the removal of NO x was examined. The plasma reactor used can be energized by either ac or pulse voltage. An attempt was made to utilize the electrical ignition system of an internal combustion engine as a high-voltage pulse generator for the plasma reactor. When the plasma reactor was energized by the electrical ignition system, NO was readily oxidized to NO 2 . Performance was as good as with ac energization. Increasing the fraction of NO 2 in NO x , which is the main role of the plasma reactor, largely enhanced the NO x removal efficiency. In the plasma–catalytic reactor, the increases in initial NO x concentration, space velocity (Feed Gas Flow rate) and humidity lowered the NO x removal efficiency. However, the reaction temperature in the range up to 473 K did not significantly affect the NO x removal efficiency in the presence of plasma discharge.
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Nonthermal Plasma-Enhanced Catalytic Removal of Nitrogen Oxides over V2O5/TiO2 and Cr2O3/TiO2
Industrial & Engineering Chemistry Research, 2003Co-Authors: Young Sun Mok, Dong Jun Koh, Kyong Tae Kim, In-sik NamAbstract:A nonthermal plasma process (dielectric-packed bed reactor) was combined with catalyst to remove nitrogen oxides (NOx). Two different honeycomb catalysts such as V2O5/TiO2 and Cr2O3/TiO2 were compared with respect to the removal characteristic of NOx. The effect of oxygen content, water vapor, Feed Gas Flow rate, reaction temperature, and initial concentration on the removal of NOx was examined. The plasma discharge was found to largely enhance the removal of NOx on the catalyst. Without plasma discharge, V2O5/TiO2 was superior to Cr2O3/TiO2 in terms of NOx removal activity. However, the degree of enhancement in NOx removal as a result of plasma discharge was similar for each system. Cr2O3/TiO2 catalyst reduced NO2 to both NO and N2 while the reduction of NO2 back to NO was not significant on V2O5/TiO2 catalyst. The combined system of the nonthermal plasma with V2O5/TiO2 catalyst removed nearly 90% of NOx at 150 °C that is a relatively low temperature, compared to the typical temperature window of NOx red...
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Oxidation of volatile organic compounds by using a microwave-induced plasma process
Korean Journal of Chemical Engineering, 2003Co-Authors: Young Sun Mok, Ho-chul Kang, Moo Hyun Cho, In-sik NamAbstract:A microwave plasma system using a 2.45 GHz magnetron was applied to the decomposition of volatile organic compounds such as toluene and trichloroethylene. Designed for producing plasma at atmospheric pressure, this microwave plasma system consists of a magnetron detached from a household microwave oven, a directional coupler, a three-stub tuner, a tapered waveguide, and plasma flame section where a quartz tube with a nozzle is located. In this system, the organic compounds can be decomposed by thermal incineration as well as by reactions with various active species formed during plasma discharge. The effect of Feed Gas Flow rate on the decomposition was significant due to the decrease in the Gas temperature, but the initial concentration in the range of 210-2,100 ppm did not largely affect the decomposition efficiency. The principal byproduct was nitrogen oxides because this system was operated at high temperature. To improve the decomposition of the organic compounds, argon was used as a plasma-assisting Gas, together with the air-like Feed Gas mixture. Large enhancement in the decomposition efficiency was achieved by the use of argon.
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Modeling of pulsed corona discharge process for the removal of nitric oxide and sulfur dioxide
Chemical Engineering Journal, 2002Co-Authors: Young Sun Mok, In-sik NamAbstract:Abstract A positive pulsed corona discharge process was applied to the removal of sulfur dioxide and nitric oxide from a simulated flue Gas stream, and a mathematical model was proposed to describe this process theoretically. The proposed model takes into account generation of radicals by pulsed corona discharge, followed by radical utilization for the removal of the pollutants. Radicals such as O, OH, N, H, etc. may be concerned in the removal of the pollutants. Their concentrations were derived by considering direct electron impact on the dissociation of Gaseous molecules (O 2 , N 2 , H 2 O) and subsequent excitation transfer reactions of excited oxygen atoms to produce O and OH radicals. The effects of various operating parameters such as Feed Gas Flow rate, initial concentration, oxygen content, humidity, peak voltage and pulse repetition rate on the removal were examined. So as to establish the validity of the model, the calculated results were compared with the experimental data. Although some discrepancy between the calculated and experimental results was observed at high pulse repetition rate, the proposed model was found to properly predict the experimental data on the whole.