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Owing to various advantages of artificial marble compared to natural marble, its application has been rising exponentially, which has resulted in the generation of a significant amount of waste artificial marble through various processes. This study focuses on the recovery of methyl methacrylate from the waste artificial marble powder through pyrolysis reaction. The pyrolysis experiment was conducted in a horizontal tubular furnace at various pyrolysis temperatures (300–500 °C) at an interval of 50 °C. The liquid product was obtained through condensation. Liquid and solid product characteristics were studied. Significant cracking of the liquid product was obtained for 450 and 500 °C. From the solid phase analysis, it was observed that aluminum oxide (Al2O3) was obtained through the calcination of waste artificial marble powder at 800 °C.
Jeeban Poudel; You Min Lee; Hyeok Jin Kim; Sea Cheon Oh. Methyl methacrylate (MMA) and alumina recovery from waste artificial marble powder pyrolysis. Journal of Material Cycles and Waste Management 2020, 23, 214 -221.
AMA StyleJeeban Poudel, You Min Lee, Hyeok Jin Kim, Sea Cheon Oh. Methyl methacrylate (MMA) and alumina recovery from waste artificial marble powder pyrolysis. Journal of Material Cycles and Waste Management. 2020; 23 (1):214-221.
Chicago/Turabian StyleJeeban Poudel; You Min Lee; Hyeok Jin Kim; Sea Cheon Oh. 2020. "Methyl methacrylate (MMA) and alumina recovery from waste artificial marble powder pyrolysis." Journal of Material Cycles and Waste Management 23, no. 1: 214-221.
Pretreatment of sewage sludge under inert condition can produce enhanced solid fuel qualities. In this study, sewage sludge was torrefied in a horizontal tubular reactor at temperatures ranging from 200 to 450 °C. Improved fuel characteristics with reduced oxidized compounds which become more like coal were depicted by the CHO index and Van Krevelen diagram. The CHO index based on molecular C, H, and O data obtained for 450 °C was − 0.65. Statistical Grindability Index (SGI) gradually decreased with the lowest value for 450 °C while the fuel ratio increased with increase in torrefaction temperature. The spontaneous combustion of sewage sludge was analyzed and the average spontaneous combustion temperature of 211.4 °C was obtained.
Joo Yeob Lee; Sujeeta Karki; Jeeban Poudel; Keun Won Lee; Sea Cheon Oh. Fuel characteristics of sewage sludge using thermal treatment. Journal of Material Cycles and Waste Management 2019, 21, 766 -773.
AMA StyleJoo Yeob Lee, Sujeeta Karki, Jeeban Poudel, Keun Won Lee, Sea Cheon Oh. Fuel characteristics of sewage sludge using thermal treatment. Journal of Material Cycles and Waste Management. 2019; 21 (4):766-773.
Chicago/Turabian StyleJoo Yeob Lee; Sujeeta Karki; Jeeban Poudel; Keun Won Lee; Sea Cheon Oh. 2019. "Fuel characteristics of sewage sludge using thermal treatment." Journal of Material Cycles and Waste Management 21, no. 4: 766-773.
The effectiveness of gas separation membranes and their application is continually growing owing to its simpler separation methods. In addition, their application is increasing for the separation of syngas (CO and H2) which utilizes cryogenic temperature during separation. Polymers are widely used as membrane material for performing the separation of various gaseous mixtures due to their attractive perm-selective properties and high processability. This study, therefore, aims to investigate the process design characteristics of syngas separation utilizing polyamide composite membrane with polyimide support. Moreover, characteristics of CO/H2 separation were investigated by varying inlet gas flow rates, stage cut, inlet gas pressures, and membrane module temperature. Beneficial impact in CO and H2 purity were obtained on increasing the flow rate with no significant effect of increasing membrane module temperature and approximately 97% pure CO was obtained from the third stage of the multi-stage membrane system.
Jeeban Poudel; Ja Hyung Choi; Sea Cheon Oh. Process Design Characteristics of Syngas (CO/H2) Separation Using Composite Membrane. Sustainability 2019, 11, 703 .
AMA StyleJeeban Poudel, Ja Hyung Choi, Sea Cheon Oh. Process Design Characteristics of Syngas (CO/H2) Separation Using Composite Membrane. Sustainability. 2019; 11 (3):703.
Chicago/Turabian StyleJeeban Poudel; Ja Hyung Choi; Sea Cheon Oh. 2019. "Process Design Characteristics of Syngas (CO/H2) Separation Using Composite Membrane." Sustainability 11, no. 3: 703.
The aim of this study was to investigate the optimal temperature range for waste wood and the effect torrefaction residence time had on torrefied biomass feedstock. Temperature range of 200–400 °C and residence time of 0–50 min were considered. In order to investigate the effect of temperature and residence time, torrefaction parameters, such as mass yield, energy yield, volatile matter, ash content and calorific value were calculated. The Van Krevelen diagram was also used for clarification, along with the CHO index based on molecular C, H, and O data. Torrefaction parameters, such as net/gross calorific value and CHO increased with an increase in torrefaction temperature, while a reduction in energy yield, mass yield, and volatile content were observed. Likewise, elevated ash content was observed with higher torrefaction temperature. From the Van Krevelen diagram, it was observed that at 300 °C the torrefied feedstock came in the range of lignite. With better gross calorific value and CHO index, less ash content and nominal mass loss, 300 °C was found to be the optimal torrefaction temperature for waste wood.
Jeeban Poudel; Sujeeta Karki; Sea Cheon Oh. Valorization of Waste Wood as a Solid Fuel by Torrefaction. Energies 2018, 11, 1641 .
AMA StyleJeeban Poudel, Sujeeta Karki, Sea Cheon Oh. Valorization of Waste Wood as a Solid Fuel by Torrefaction. Energies. 2018; 11 (7):1641.
Chicago/Turabian StyleJeeban Poudel; Sujeeta Karki; Sea Cheon Oh. 2018. "Valorization of Waste Wood as a Solid Fuel by Torrefaction." Energies 11, no. 7: 1641.
Thermal pre-treatment of non-lignocellulosic biomass, sewage sludge, using a lab-scale fluidized bed reactor was carried out in order to enhance its solid fuel properties. The influence of the torrefaction temperature range from 200–350 °C and 0–50 min residence time on the physical and chemical properties of the torrefied product was investigated. Properties of the torrefied product were analyzed on the basis of the degree of torrefaction, ultimate and proximate analysis, and gas analysis. An attempt was made to obtain the chemical exergy of sewage sludge. An elevated torrefaction temperature presented a beneficial impact on the degree of torrefaction and chemical exergy. Moreover, the effect of the torrefaction temperature and residence time on the elemental variation of sewage sludge exhibited an increase in the weight percentage of carbon while the H/C and O/C molar ratios deteriorated. Additionally, the product gas emitted during torrefaction was analyzed to study the pathway of hydrocarbons and oxygen containing compounds. The compounds with oxygen were emitted at higher temperatures in contrast to hydrocarbon gases. In addition, the study of various correlations for predicting the calorific value of torrefied sewage sludge was made.
Sujeeta Karki; Jeeban Poudel; Sea Cheon Oh. Thermal Pre-Treatment of Sewage Sludge in a Lab-Scale Fluidized Bed for Enhancing Its Solid Fuel Properties. Applied Sciences 2018, 8, 183 .
AMA StyleSujeeta Karki, Jeeban Poudel, Sea Cheon Oh. Thermal Pre-Treatment of Sewage Sludge in a Lab-Scale Fluidized Bed for Enhancing Its Solid Fuel Properties. Applied Sciences. 2018; 8 (2):183.
Chicago/Turabian StyleSujeeta Karki; Jeeban Poudel; Sea Cheon Oh. 2018. "Thermal Pre-Treatment of Sewage Sludge in a Lab-Scale Fluidized Bed for Enhancing Its Solid Fuel Properties." Applied Sciences 8, no. 2: 183.
A lab-scale downdraft fixed bed reactor was used for the study of sewage sludge, a non-lignocellulosic biomass, torrefaction to enhance the thermochemical properties of sewage sludge. The torrefaction was carried out for a temperature range of 200–350 °C and a residence time of 0–50 min. Degree of torrefaction, torrefaction index, chemical exergy, gas analysis, and molar ratios were taken into account to analyze the torrefied product with respect to torrefaction temperature. The effect of torrefaction temperature was very pronounced and the temperature range of 250–300 °C was considered to be the optimum torrefaction temperature range for sewage sludge. Chemical exergy, calorific value and torrefaction index were significantly influenced by the change in the relative carbon content resulting in decrease of the O/C and H/C molar ratios.
Sujeeta Karki; Jeeban Poudel; Sea Cheon Oh. Utilizing Downdraft Fixed Bed Reactor for Thermal Upgrading of Sewage Sludge as Fuel by Torrefaction. Applied Sciences 2017, 7, 1189 .
AMA StyleSujeeta Karki, Jeeban Poudel, Sea Cheon Oh. Utilizing Downdraft Fixed Bed Reactor for Thermal Upgrading of Sewage Sludge as Fuel by Torrefaction. Applied Sciences. 2017; 7 (11):1189.
Chicago/Turabian StyleSujeeta Karki; Jeeban Poudel; Sea Cheon Oh. 2017. "Utilizing Downdraft Fixed Bed Reactor for Thermal Upgrading of Sewage Sludge as Fuel by Torrefaction." Applied Sciences 7, no. 11: 1189.
Transesterification of waste vegetable oil is one of the promising partial substitutes for fossil fuels. The degradation characteristics of waste vegetable oil using supercritical alcohols (ethanol and methanol) have been studied in this research. The elementary target was to conduct comparative analysis of the effect of supercritical methanol and supercritical ethanol as solvents on the transesterification along with the analysis of product obtained in terms of carbon number. The experiments were carried out at transesterification temperatures of 250, 270 and 290 °C, retention time of 0 to 60 min at an interval of 15 min and oil to alcohol molar ratios of 1:6, 1:12 and 1:18 for both alcohols. The conversion increased with increase in transesterification temperature and retention time. At 290 °C, almost 99% conversion was achieved for 60-min holding time for both alcohols. Increase in conversion of waste vegetable oil was observed as the molar ratio increased. Supercritical transesterification resulted into ester yield higher than 95% with non-ester composition and glycerol collectively less than 5%.
Sujeeta Karki; Nawaraj Sanjel; Jeeban Poudel; Ja Hyung Choi; Sea Cheon Oh. Supercritical Transesterification of Waste Vegetable Oil: Characteristic Comparison of Ethanol and Methanol as Solvents. Applied Sciences 2017, 7, 632 .
AMA StyleSujeeta Karki, Nawaraj Sanjel, Jeeban Poudel, Ja Hyung Choi, Sea Cheon Oh. Supercritical Transesterification of Waste Vegetable Oil: Characteristic Comparison of Ethanol and Methanol as Solvents. Applied Sciences. 2017; 7 (6):632.
Chicago/Turabian StyleSujeeta Karki; Nawaraj Sanjel; Jeeban Poudel; Ja Hyung Choi; Sea Cheon Oh. 2017. "Supercritical Transesterification of Waste Vegetable Oil: Characteristic Comparison of Ethanol and Methanol as Solvents." Applied Sciences 7, no. 6: 632.
Comparative analysis of transesterification of virgin cooking oil (VCO) and waste cooking oil (WCO) in catalyzed and supercritical transesterification process using methanol and ethanol as solvents has been conducted in this study. The luminous point of this research was the direct comparison of catalytic and supercritical process using the ester composition obtained from virgin cooking oil and waste cooking oil transesterification. Oil to alcohol molar ratio of 1:6 and reaction condition of 65 °C and 1 bar pressure were considered for the catalytic process, while 260 °C and high pressure (65 and 75 bar for methanol and ethanol, respectively) were accounted for the supercritical process. Distinct layer separation was observed for both processes. Ester, fatty acid and glycerol composition was studied for both the upper and lower layers separately, from which 100% ester composition in the upper layer and a mixture of ester and other composition in the lower layer was obtained for the catalytic process owing to succeeding filtration and washing. However, mixture of ester (>75%) and other composition was obtained in both layers for the supercritical process where purification process was not implemented. The similarity in the result obtained demonstrates the superiority of waste cooking oil compared to virgin cooking oil, taking cost into consideration.
Jeeban Poudel; Sujeeta Karki; Nawaraj Sanjel; Malesh Shah; Sea Cheon Oh. Comparison of Biodiesel Obtained from Virgin Cooking Oil and Waste Cooking Oil Using Supercritical and Catalytic Transesterification. Energies 2017, 10, 546 .
AMA StyleJeeban Poudel, Sujeeta Karki, Nawaraj Sanjel, Malesh Shah, Sea Cheon Oh. Comparison of Biodiesel Obtained from Virgin Cooking Oil and Waste Cooking Oil Using Supercritical and Catalytic Transesterification. Energies. 2017; 10 (4):546.
Chicago/Turabian StyleJeeban Poudel; Sujeeta Karki; Nawaraj Sanjel; Malesh Shah; Sea Cheon Oh. 2017. "Comparison of Biodiesel Obtained from Virgin Cooking Oil and Waste Cooking Oil Using Supercritical and Catalytic Transesterification." Energies 10, no. 4: 546.
In this work, the characteristics of waste pig fat degradation using supercritical alcohols have been studied. Comparative analysis of the influence of supercritical methanol and supercritical ethanol as solvents on the transesterification was the primary focus of this research. The experiments were carried out with waste pig fat to alcohol weight ratios of 1:1.5 (molar ratio: 1:40.5 for methanol and 1:28 for ethanol), 1:2.0 (molar ratio: 1:54 for methanol and 1:37.5 for ethanol) and 1:2.5 (molar ratio: 1:67.5 for methanol and 1:47 for ethanol) at transesterification temperatures 250, 270 and 290 °C for holding time 0, 15, 30, 45 and 60 min. Increase in the transesterification and holding time increased the conversion while increase in alcohol amount from 1:1.5 to 1:2.0 and 1:2.5 had minimal effect on the conversion. Further, majority of the ester composition in using SCM as solvent falls in the carbon range of C17:0, C19:1 and C19:2 while that for SCE falls in the carbon range of C18:0, C20:1 and C20:2. Glycerol was only present while using SCM as solvent.
Jeeban Poudel; Malesh Shah; Sujeeta Karki; Sea Cheon Oh. Qualitative Analysis of Transesterification of Waste Pig Fat in Supercritical Alcohols. Energies 2017, 10, 265 .
AMA StyleJeeban Poudel, Malesh Shah, Sujeeta Karki, Sea Cheon Oh. Qualitative Analysis of Transesterification of Waste Pig Fat in Supercritical Alcohols. Energies. 2017; 10 (3):265.
Chicago/Turabian StyleJeeban Poudel; Malesh Shah; Sujeeta Karki; Sea Cheon Oh. 2017. "Qualitative Analysis of Transesterification of Waste Pig Fat in Supercritical Alcohols." Energies 10, no. 3: 265.
This paper describes the effect of torrefaction on the characteristics of empty fruit bunches (EFB) and palm kernel shell (PKS). The torrefaction of EFB and PKS was investigated in a horizontal tubular reactor at a temperature ranging from 150 to 600 °C, for torrefaction residence time varying from 0 to 50 min. The torrefied products were characterized in terms of their elemental composition, energy yield, ash content and volatile fraction. The present study developed the torrefaction kinetics of EFB and PKS in a thermogravimetric analyzer to obtain the kinetic parameters. EFB and PKS exhibited excellent energy yield values. The gaseous products from torrefaction of EFB and PKS were also analyzed. Furthermore, the study reveals that the carbon content increases with an increasing torrefaction temperature but the O/C ratio, hydrogen and oxygen content decrease for both EFB and PKS. The energy yield and mass yield were found to decrease with an increase in the torrefaction temperature while the higher heating value (HHV) increased. From this study, torrefaction temperature between 290 and 320 °C is the optimum torrefaction temperature for EFB while torrefaction temperature between 300 and 320 °C is the optimum torrefaction temperature for PKS.
Jeeban Poudel; Tae-In Ohm; Jae Hoi Gu; Myung Chul Shin; Sea Cheon Oh. Comparative study of torrefaction of empty fruit bunches and palm kernel shell. Journal of Material Cycles and Waste Management 2016, 19, 917 -927.
AMA StyleJeeban Poudel, Tae-In Ohm, Jae Hoi Gu, Myung Chul Shin, Sea Cheon Oh. Comparative study of torrefaction of empty fruit bunches and palm kernel shell. Journal of Material Cycles and Waste Management. 2016; 19 (2):917-927.
Chicago/Turabian StyleJeeban Poudel; Tae-In Ohm; Jae Hoi Gu; Myung Chul Shin; Sea Cheon Oh. 2016. "Comparative study of torrefaction of empty fruit bunches and palm kernel shell." Journal of Material Cycles and Waste Management 19, no. 2: 917-927.
Malesh Shah; Jeeban Poudel; Hyun Kwak; Sea Cheon Oh. Kinetic analysis of transesterification of waste pig fat in supercritical alcohols. Process Safety and Environmental Protection 2015, 98, 239 -244.
AMA StyleMalesh Shah, Jeeban Poudel, Hyun Kwak, Sea Cheon Oh. Kinetic analysis of transesterification of waste pig fat in supercritical alcohols. Process Safety and Environmental Protection. 2015; 98 ():239-244.
Chicago/Turabian StyleMalesh Shah; Jeeban Poudel; Hyun Kwak; Sea Cheon Oh. 2015. "Kinetic analysis of transesterification of waste pig fat in supercritical alcohols." Process Safety and Environmental Protection 98, no. : 239-244.
Jeeban Poudel; Tae-In Ohm; Sea Cheon Oh. A study on torrefaction of food waste. Fuel 2015, 140, 275 -281.
AMA StyleJeeban Poudel, Tae-In Ohm, Sea Cheon Oh. A study on torrefaction of food waste. Fuel. 2015; 140 ():275-281.
Chicago/Turabian StyleJeeban Poudel; Tae-In Ohm; Sea Cheon Oh. 2015. "A study on torrefaction of food waste." Fuel 140, no. : 275-281.
Dae-Won Lim; Jeeban Poudel; Sea Cheon Oh. A Study on Torrefaction Characteristics of Sewage Sludge. Applied Chemistry for Engineering 2014, 25, 510 -514.
AMA StyleDae-Won Lim, Jeeban Poudel, Sea Cheon Oh. A Study on Torrefaction Characteristics of Sewage Sludge. Applied Chemistry for Engineering. 2014; 25 (5):510-514.
Chicago/Turabian StyleDae-Won Lim; Jeeban Poudel; Sea Cheon Oh. 2014. "A Study on Torrefaction Characteristics of Sewage Sludge." Applied Chemistry for Engineering 25, no. 5: 510-514.
This study presents the effects of torrefaction on the basic characteristics of corn stalks. Corn stalks were torrefied in a horizontal tubular reactor at temperatures ranging from 150 °C to 400 °C, for torrefaction periods varying from 0 min to 50 min. The torrefied corn stalk products were characterized in terms of their elemental composition, energy yield, ash content, and volatile fraction. The gaseous products were also analyzed. Thermogravimetric analysis (TGA) of the samples was carried out in order to obtain the apparent activation energy for the torrefaction of corn stalks. The weight loss data according to the degradation temperature were analyzed using three different methods. The energy and mass yield were found to decrease with an increase in the temperature, whereas the higher heating value (HHV) increased. From this work, it was found that the compounds with oxygen were emitted at a temperature lower than that for hydrocarbon gases and the temperatures of 290–330 °C were the optimum torrefaction temperatures for corn stalks.
Jeeban Poudel; Sea Cheon Oh. Effect of Torrefaction on the Properties of Corn Stalk to Enhance Solid Fuel Qualities. Energies 2014, 7, 5586 -5600.
AMA StyleJeeban Poudel, Sea Cheon Oh. Effect of Torrefaction on the Properties of Corn Stalk to Enhance Solid Fuel Qualities. Energies. 2014; 7 (9):5586-5600.
Chicago/Turabian StyleJeeban Poudel; Sea Cheon Oh. 2014. "Effect of Torrefaction on the Properties of Corn Stalk to Enhance Solid Fuel Qualities." Energies 7, no. 9: 5586-5600.
Kyung Seok Choi; Jeeban Poudel; Sea Cheon Oh. Influence of Temperature on Separation of CO and H2Mixed Gas Using Polyamide Composite Membrane. Clean Technology 2012, 18, 360 -365.
AMA StyleKyung Seok Choi, Jeeban Poudel, Sea Cheon Oh. Influence of Temperature on Separation of CO and H2Mixed Gas Using Polyamide Composite Membrane. Clean Technology. 2012; 18 (4):360-365.
Chicago/Turabian StyleKyung Seok Choi; Jeeban Poudel; Sea Cheon Oh. 2012. "Influence of Temperature on Separation of CO and H2Mixed Gas Using Polyamide Composite Membrane." Clean Technology 18, no. 4: 360-365.
In this work, the characteristics of wood degradation using supercritical alcohols have been studied. Supercritical ethanol and supercritical methanol were used as solvents. The kinetics of wood degradation were analyzed using the nonisothermal weight loss technique with heating rates of 3.1, 9.8, and 14.5 °C/min for ethanol and 5.2, 11.3, and 16.3 °C/min for methanol. Three different kinetic analysis methods were implemented to obtain the apparent activation energy and the overall reaction order for wood degradation using supercritical alcohols. These were used to compare with previous data for supercritical methanol. From this work, the activation energies of wood degradation in supercritical ethanol were obtained as 78.0–86.0, 40.1–48.1, and 114 kJ/mol for the different kinetic analysis methods used in this work. The activation energies of wood degradation in supercritical ethanol were obtained as 78.0–86.0, 40.1–48.1, and 114 kJ/mol. This paper also includes the analysis of the liquid products obtained from this work. The characteristic analysis of liquid products on increasing reaction temperature and time has been performed by GC-MS. The liquid products were categorized according to carbon numbers and aromatic/aliphatic components. It was found that higher conversion in supercritical ethanol occurs at a lower temperature than that of supercritical methanol. The product analysis shows that the majority of products fall in the 2 to 15 carbon number range.
Jeeban Poudel; Sea Cheon Oh. Degradation Characteristics of Wood Using Supercritical Alcohols. Energies 2012, 5, 5038 -5052.
AMA StyleJeeban Poudel, Sea Cheon Oh. Degradation Characteristics of Wood Using Supercritical Alcohols. Energies. 2012; 5 (12):5038-5052.
Chicago/Turabian StyleJeeban Poudel; Sea Cheon Oh. 2012. "Degradation Characteristics of Wood Using Supercritical Alcohols." Energies 5, no. 12: 5038-5052.
The kinetic analysis method for degradation of wood in supercritical ethanol and methanol was proposed in this work. This method was applied to predict the degradation of wood in supercritical ethanol and supercritical methanol by a nonisothermal weight loss technique with heating rates of 3.1, 9.8, and 14.5 °C/min for ethanol and 5.2, 11.3, 16.3 °C/min for methanol. To verify the effectiveness of the kinetic analysis proposed in this work, the experimental values were compared with those of the numerical integration results using kinetic parameters obtained in this work. The kinetic analysis method proposed in this work gave reliable values of kinetic parameter for wood degradation in supercritical ethanol and supercritical methanol. To understand the effectiveness of the solvents as supercritical fluid, the calculation results of wood weight loss using the kinetic parameters obtained from this work were studied at a heating rate of 7 °C/min for both supercritical ethanol (SCE) and supercritical methanol (SCM). From this work, it can be seen that SCE is better solvent than SCM for wood degradation in supercritical alcohols.
Jeeban Poudel; Sea Cheon Oh. A Kinetic Analysis of Wood Degradation in Supercritical Alcohols. Industrial & Engineering Chemistry Research 2012, 51, 4509 -4514.
AMA StyleJeeban Poudel, Sea Cheon Oh. A Kinetic Analysis of Wood Degradation in Supercritical Alcohols. Industrial & Engineering Chemistry Research. 2012; 51 (12):4509-4514.
Chicago/Turabian StyleJeeban Poudel; Sea Cheon Oh. 2012. "A Kinetic Analysis of Wood Degradation in Supercritical Alcohols." Industrial & Engineering Chemistry Research 51, no. 12: 4509-4514.