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Full-Text Articles in Engineering
Synthesis Of Mwcnts By Chemical Vapor Deposition From Methane Using Femo/Mgo Catalyst : Role Of Hydrogen And Kinetic Study, Chawalkul Chotmunkhongsin
Synthesis Of Mwcnts By Chemical Vapor Deposition From Methane Using Femo/Mgo Catalyst : Role Of Hydrogen And Kinetic Study, Chawalkul Chotmunkhongsin
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this study, carbon nanotubes (CNTs) were synthesized by chemical vapor deposition (CCVD) of methane over FeMo/MgO catalyst in a fixed-bed reactor. The role of hydrogen on CNTs synthesis and kinetics of CNTs formation were experimentally investigated. The study revealed that hydrogen in the catalyst reduction process plays an important role in the structural changes of FeMo/MgO catalyst. The catalyst structure fully transformed into metallic FeMo, resulting in the increased yield of 5 folds higher than the non-reduced catalyst. However, the slightly larger diameter and lower crystallinity ratio of CNTs was obtained. The hydrogen co-feeding during the synthesis can slightly …
Novel Electrochemical Packed-Bed Reactor For Carbon Dioxide Reduction, Suwakul Chaiwarit
Novel Electrochemical Packed-Bed Reactor For Carbon Dioxide Reduction, Suwakul Chaiwarit
Chulalongkorn University Theses and Dissertations (Chula ETD)
Electrochemical reduction of carbon dioxide (CO2) is a promising strategy to recycle CO2 into valuable chemical products. Nevertheless, a conventional apparatus which usually utilizes stack design to maximize its surface-to-volume ratio requires many elements and complicated instruction assembly. The stack design often requires feed streams to flow in narrow channels throughout the cell, which is also constrained by membrane size roughly 1 m2 by current manufacture technology. This research focuses on development of a new type of electrochemical reactor that is suitable for industrial-scale applications. The novel electrochemical packed-bed reactor is designed for the electroreduction to covert CO2 into CO …
Effect Of Molecular Sieve Addition On Methanol Synthesis From Co2 And H2 Through Alcohol Assisted Method Over Cu/Zno Catalyst, Tanawut Boonamnuay
Effect Of Molecular Sieve Addition On Methanol Synthesis From Co2 And H2 Through Alcohol Assisted Method Over Cu/Zno Catalyst, Tanawut Boonamnuay
Chulalongkorn University Theses and Dissertations (Chula ETD)
Low-temperature methanol synthesis from CO2 and H2 was carried out using ethanol as catalytic solvent. The alcohol-assisted method reduced synthesis temperature and enhanced methanol yield (35.8%) at 150 oC (5.0 MPa, Cu/ZnO catalyst). However, ethyl acetate and water were generated as byproducts from the reaction. The byproducts formed azeotrope mixture with methanol and led to a complex product purification. Therefore, in this study, molecular sieves (MS) were introduced to adsorb the byproducts. The effect of different MS (3A and 5A) was studied. It was found that MS helped enhancing methanol yield. The highest methanol yield (42.6%) was obtained when adding …
Effect Of Cocatalyst Combination In Titanium-Based Ziegler-Natta Catalyst On Olefin Polymerization, Thanyaporn Pongchan
Effect Of Cocatalyst Combination In Titanium-Based Ziegler-Natta Catalyst On Olefin Polymerization, Thanyaporn Pongchan
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research focused on effect of cocatalyst types (TEA, TnOA, and TEA+TnOA) on titanium-based Ziegler-Natta catalyst in olefin polymerization both in slurry and gas-phase systems. This study has been divided into four sections. The commercial titanium-based catalyst was selected to investigate effect of reaction temperature and oxidation state of titanium from ESR measurement on slurry ethylene and propylene polymerization in the first and the second parts, respectively. The commercial catalyst with TEA exhibited the highest activity in ethylene polymerization. However, divalent, and trivalent of titanium (Ti2+ and Ti3+) was active in ethylene polymerization to produce more polymer. Stability of Ti3+ …
Deactivation Of Pdni Catalyst On Nanoporous Carbon Support Derived From Cattail Leaves In Synthesis Of Partially Hydrogenated Biodiesel(H-Fame), Tripob Longprang
Deactivation Of Pdni Catalyst On Nanoporous Carbon Support Derived From Cattail Leaves In Synthesis Of Partially Hydrogenated Biodiesel(H-Fame), Tripob Longprang
Chulalongkorn University Theses and Dissertations (Chula ETD)
Nowadays, biodiesel is an alternative energy that is widely used to replace fossil fuels because of its high heat value comparable to fossil fuels. Biodiesel was easily oxidized within air. It is commonly blended with diesel fuel to have the proper properties and increase shelf life. Partial hydrogenation is one of the processes used to enhance the properties of biodiesel. In this research, bimetallic PdNi on nanoporous carbon (NPC) support derived from cattail leaves was successfully synthesized via hydrothermal carbonization and chemical activation. The prepared nanoporous carbon has a high surface area of 2002 m2g-1, obtained by activation process with …
Synthesis, Characteristic And Application Of Mesocellular Foam Carbon (Mcf-C) As Catalyst For Dehydrogenation Of Ethanol, Yoottapong Klinthongchai
Synthesis, Characteristic And Application Of Mesocellular Foam Carbon (Mcf-C) As Catalyst For Dehydrogenation Of Ethanol, Yoottapong Klinthongchai
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research aims to investigate the synthesis of MCF-C as catalyst for dehydrogenation of ethanol. The study was classified into 3 parts. In the first part, the mesocellular foam silica (MCF-Si) was converted to mesocellular foam carbon using a surfactant residue as a carbon source, and followed by testing the dehydrogenation of ethanol to acetaldehyde. Surfactant residue in the inside of MCF-Si could be used as the carbon source for MCF-C synthesis. The obtained material could maintain the meso-structure, and exhibited higher activity for ethanol dehydrogenation in comparison to MCF-Si. For the second part, MCF-C was examined for 12 h …
A Comparative Simulation Of Glycerol Steam Reforming With Foam And Conventional Pellet Catalysts In Packed Bed Reactor, Chattharika Phitchayakorn
A Comparative Simulation Of Glycerol Steam Reforming With Foam And Conventional Pellet Catalysts In Packed Bed Reactor, Chattharika Phitchayakorn
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research aimed to study the effect of different catalyst structures to the hydrogen production process with glycerol steam reforming in packed bed reactors via the COMSOL Multiphysics program. 2D pseudo-homogeneous steady-state model of a 6-inch diameter adiabatic reactor has been developed to describe a transport phenomenon inside the packed bed reactors with two different catalyst structures of conventional 1-inch pellet catalyst and 10-30PPI foam catalyst. The simulated results show that the novel foam catalyst improved the process performance in terms of pressure drop and hydrogen yield comparing to the conventional 1-inch pellet catalyst. The reactor packed with the conventional …
Production Of Γ-Valerolactone (Gvl) From One-Pot Cascade Transformation Of Furfural Over Pt/Zeolite-Based Catalysts, Jukkapan Saengin
Production Of Γ-Valerolactone (Gvl) From One-Pot Cascade Transformation Of Furfural Over Pt/Zeolite-Based Catalysts, Jukkapan Saengin
Chulalongkorn University Theses and Dissertations (Chula ETD)
γ-valerolactone (GVL) is a green renewable resource, which can be used as fuel additives, organic solvent in food industries, pharmaceutical intermediates. The direct production of GVL from furfural in a one-pot transformation is highly desirable in order to minimize the use of solvents, the number of unit operations, and the production cost. The cascade reaction was carried out in a single reactor, using a secondary alcohol as the hydrogen donor with acid catalysts (so-called Meerwein–Ponndorf–Verley reaction). In this work, the transfer hydrogenation of furfural with 2-propanal as a hydrogen donor was investigated on various zeolites including of HY with Si/Al …
Electrochemical Reduction Of Carbon Dioxide To Formate On Bi And Bisn Electrodes Prepared By Electrodeposition On Copper Foil, Jutamas Wasombut
Electrochemical Reduction Of Carbon Dioxide To Formate On Bi And Bisn Electrodes Prepared By Electrodeposition On Copper Foil, Jutamas Wasombut
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this study, The Bix/Cu electrocatalysts were prepared by electrodeposition of Bi on Cu foil, and the BixSny/Cu electrocatalysts were prepared by electrodeposition of Bi and Sn on Cu foil in deposition solution bath with different Bi3+ ion concentrations of 0.05, 0.1, and 0.2 M (Bi0.05/Cu, Bi0.1/Cu, Bi0.2/Cu), while the Sn2+ ion concentration was constant at 0.025 M (Bi0.05Sn0.025/Cu, Bi0.1Sn0.025/Cu, Bi0.2Sn0.025/Cu). The electrocatalysts were characterized by SEM-EDX, XRD, and XPS and tested in the electrochemical CO2 reduction reaction. The results demonstrate that the Bi concentrations in the deposition bath affect the structure of Bi into different forms, including bulky structure …
Selective Hydrogenation Of Acetophenone To 1-Phenylethanol On Pt/ Tio2 Catalysts Prepared By Pulsed Dc Magnetron Sputtering, Khunarnon Ditsataporncharoen
Selective Hydrogenation Of Acetophenone To 1-Phenylethanol On Pt/ Tio2 Catalysts Prepared By Pulsed Dc Magnetron Sputtering, Khunarnon Ditsataporncharoen
Chulalongkorn University Theses and Dissertations (Chula ETD)
1-Phenylethanol (PHE) is a high-value chemical with various applications in fragrance and pharmaceutical industries. It is extensively used as strawberry fragrance additives in yogurts and chewing gums and an intermediate of anti-inflammatory drugs such as Ibuprofen. In this study, selective hydrogenation of acetophenone (AP) to PHE was investigated using platinum catalysts supported on different types of titanium dioxide including PC500 (pure anatase) and P25 (anatase mixed rutile). Pt was deposited on the titanium dioxide supports by pulsed direct current magnetron sputtering (PDC-MSD) method with deposition time spent on Pt coating at 3, 6, and 9 minutes. For comparison purposes, Pt/TiO2 …
Electrochemical Reduction Of Co2 To Co On Zn Electrodes Prepared By Electrodeposition Method, Krongkwan Poonbun
Electrochemical Reduction Of Co2 To Co On Zn Electrodes Prepared By Electrodeposition Method, Krongkwan Poonbun
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, the effect of substrates including Cu and Ti on the catalytic activity of Zn electrocatalysts prepared by electrodeposition method was investigated in the electrochemical reduction of CO2 (CO2ER). As analyzed by SEM-EDX and XRD results, it indicated that the different substrates did not have any influence on the morphologies of catalysts and the conductivity of substrate was the main factor on the CO2ER performance. The effect of Zn precursor concentration in the range of 0.025 M to 0.4 M was further studied on the characteristics and the activity of Zn/Cu catalysts in the CO2ER. . At low …
Effect Of Single Metal Loading On Cao/Al2o3 Pellet Catalyst For Biodiesel Production, Nattawadee Munbupphachart
Effect Of Single Metal Loading On Cao/Al2o3 Pellet Catalyst For Biodiesel Production, Nattawadee Munbupphachart
Chulalongkorn University Theses and Dissertations (Chula ETD)
Biodiesel is a sustainable biofuel mainly derived from transesterification of vegetable oil or animal fat. Transesterification is increasingly being catalyzed by heterogeneous catalysts in recent years. As a result of a high-pressure drop, solid base catalysts in a powder form are not suitable for a continuous process. A pellet catalyst is more convenient, but it has lower surface per volume as well as lower in its catalytic activity for transesterification. This research aims at studying the effect of metal oxides loading on CaO/Al2O3 pellet catalyst for improvement of catalytic activity of transesterification. The 20 wt.% single metal loading of metal …
Methanol Synthesis Via Hydrogenation Of Mixed Co/Co2 Over Mn Modified Cu/Zno/Al2o3 Catalyst, Papawin Tunyasitikun
Methanol Synthesis Via Hydrogenation Of Mixed Co/Co2 Over Mn Modified Cu/Zno/Al2o3 Catalyst, Papawin Tunyasitikun
Chulalongkorn University Theses and Dissertations (Chula ETD)
The purposes of this study are to investigate the methanol synthesis by using mixed CO/CO2 hydrogenation on Mn modified Cu/ZnO/Al2O3 catalyst which is prepared by the co-precipitation method and to investigate the overall energy consumption of methanol synthesis based on experimental results through the simulation process using Aspen Plus V.9. The improvement of catalytic activity is performed by a continuous fixed bed microreactor at 250°C under atmospheric pressure for 5 hours on the stream through hydrogenation of different feed composition of CO2/H2, CO/H2, and CO/CO2/H2, and 24000 ml/gcat∙h of GHSV. The physical and chemical properties of the catalysts are measured …
Performance Of Carbon Nanotubes As Supports Of Nickel-Iron Catalysts For Carbon Dioxide Methanation, Phanatchakorn Mala
Performance Of Carbon Nanotubes As Supports Of Nickel-Iron Catalysts For Carbon Dioxide Methanation, Phanatchakorn Mala
Chulalongkorn University Theses and Dissertations (Chula ETD)
Nowadays, an increase in CO2 emission is one of the main reasons of global warming. Many studies have tried to solve the problem by developing catalysts to efficiently convert CO2 into CH4. Herein, bimetallic Ni-Fe catalyst was studied to improve the catalyst activity of Ni-based catalyst which has low activity and is easily deactivated. Carbon nanotubes (CNTs) have been identified as one of the most promising nanomaterials with unique electrical, thermal, and mechanical properties. In this thesis, CNTs was synthesized from eucalyptus oil as a renewable carbon source and then employed as catalyst support material in methanation. Variations of synthesis …
Deoxygenation Of Palm Fatty Acid Distillate To Green Diesel Over Molybdenum Nitride And Carbide-Based Catalysts In A Trickle-Bed Reactor, Wanwipa Leangsiri
Deoxygenation Of Palm Fatty Acid Distillate To Green Diesel Over Molybdenum Nitride And Carbide-Based Catalysts In A Trickle-Bed Reactor, Wanwipa Leangsiri
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this present work, the deoxygenation of palm fatty acid distillate (PFAD) to green diesel over γ-Al2O3 supported bimetallic CoMo and NiMo carbide and nitride catalysts was conducted in a trickle bed reactor. The catalysts were prepared by a single-step decomposition method of mixture containing hexamethylenetetramine and corresponding metal salts in presence of hydrogen and nitrogen for carbide and nitride forms, respectively at 700 oC. The prepared catalysts were characterized by XRD, XPS, N2-sorption, SEM/EDX and TGA techniques. The catalyst performance was evaluated at a temperature of 330 °C, hydrogen pressure of 5 MPa, LHSV of 1 h−1, and H2/feed …
Esterification Of Ethanol And Lactic Acid With Wo3 On Montmorillonite Catalysts For Ethyl Lactate Production, Suthicha Mukjinda
Esterification Of Ethanol And Lactic Acid With Wo3 On Montmorillonite Catalysts For Ethyl Lactate Production, Suthicha Mukjinda
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research aims to study the characteristics, catalytic properties and stability of tungsten oxide (13.5 wt%) supported on montmorillonite (W/MMT) catalysts prepared by using three different calcination temperatures including 375 (W/MMT375), 475 (W/MMT475) and 575 (W/MMT 575) °C. All catalysts were examined in esterification of ethanol and lactic acid at 80 °C. Characterization studies showed that the W/MMT475 catalyst exhibited the highest acidity, followed by W/MMT375 and W/MMT575, respectively. However, from the surface area result, W/MMT375 exhibited the highest surface area, followed by W/MMT475 and W/MMT575, respectively. When all catalysts were tested in esterification of ethanol and lactic acid, it …