Semih Eser | Istanbul University (original) (raw)

Papers by Semih Eser

Petroleum Refining and Natural Gas Processing

Chemical engineering transactions, 2021

Activated carbons (AC) are widely used in a variety of applications because of their controllable... more Activated carbons (AC) are widely used in a variety of applications because of their controllable porosity and surface functionalities. In this work, AC were prepared from different hard woods through one- and two-step pyrolysis/activation for the adsorption of organic pollutants in water. Water vapor was used as the activating agent. The influence of the precursor and preparation methods on the properties of the resulting AC was evaluated through multiple techniques. Temperature-programmed oxidation (TPO) measured the reactivity toward oxygen of chars and AC, while temperature-programmed desorption coupled with mass spectrometry (TPD/MS) revealed functional groups on AC surface. Methylene blue adsorption tests evaluated the adsorption capacity of the prepared AC and the presence of mesopores. Depending on the oxidation reactivity of the char produced by pyrolysis, the resulting AC show different surface composition and adsorption performance. With the increasing char oxidation reac...

... WP-TR-2000-2120 FUEL DEGRADATION AND ALLIED STUDIES DELIVERY ORDER 5 ANDRE BOEHMAN, SEMIH ESE... more ... WP-TR-2000-2120 FUEL DEGRADATION AND ALLIED STUDIES DELIVERY ORDER 5 ANDRE BOEHMAN, SEMIH ESER, PAT ... I PROPULSION DIRECTORATE AIR FORCE RESEARCH LABORATORY AIR FORCE MATERIEL COMMAND WRIGHT-PATTERSON AIR FORCE ...

ACS Symposium Series, 2005

... Semih Eser, Guohua Wang, and Jennifer Clemons ... Hydrotreated samples gave high degrees of m... more ... Semih Eser, Guohua Wang, and Jennifer Clemons ... Hydrotreated samples gave high degrees of mesophase development (OTIs 91 and 93) presumably because of the low rate of carbonization due to the abundance of partially hydrogenated aromatics that act as hydrogen ...

KONA Powder and Particle Journal, 2007

The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and lase... more The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and laser light scattering. Vitrain samples were collected from obvious tree remains located in the ceilings of two Appalachian coal mines. Wet sieving produced narrow size cuts. The particles were determined to be oblong or blocky in shape, with average length-to-width ratio of 1.7 and sphericity of 0.78. They were analogous in shape to a square ended, rectangular "house brick". The two bituminous coals and different size cuts of each coal had essentially the same shape parameters. Characteristic heating times and terminal velocities were higher by 22 and 20%, respectively compared to spherical particles.

Applied Catalysis B: Environmental, 2015

This study analyzes the influence of chemical and physical properties of Pd/C and Pt/C hydrodechl... more This study analyzes the influence of chemical and physical properties of Pd/C and Pt/C hydrodechlorination (HDC) catalysts in the different evolution of their activity during time on stream. Pt/C showed stable activity in the HDC of dichloromethane (DCM) and chloroform (TCM), while Pd/C was deactivated after 90 hours of operation, particularly during HDC of DCM. The deactivation of Pd/C catalyst can be attributed to the lower proportion of zero-valent species and larger metal particle size. This appears to hinder the H 2 dissociation, enhance the irreversible chemisorption of reactants and reaction products, and favor coupling reactions (leading to the formation of carbonaceous deposits) and/or metal phase change reactions. The more extensive deactivation of Pd/C in the HDC of DCM is attributed to the stronger chemisorption of the reactant on the catalyst, which leads to the formation of a new PdC x phase by the incorporation of carbon atoms into the metal lattice.

Task 1: Investigation of the Quantitative Degradation Chemistry of Fuels.

Springer Series in Materials Science, 1998

... Page 172. 152 Semih Eser Figure 3 shows a plot of the concentrations of the six groups of com... more ... Page 172. 152 Semih Eser Figure 3 shows a plot of the concentrations of the six groups of com-pounds identified in the second set of decant oil and thermal tar samples. ... Solid State Chem. 9. 59 (1974) 8. H. Marsh, PL Walker. ...

Industrial & Engineering Chemistry Research, 2010

IEEE Antennas and Propagation Magazine, 2010

O pen-area test site (OATS) calibration is a fundamental antenna-engineering task. This issue's t... more O pen-area test site (OATS) calibration is a fundamental antenna-engineering task. This issue's tutorial is on the cali bration of an open-area test site. The requirements, the theoretical basis, related standards, and the procedure to be followed are dis cussed in this tutorial. The next tutorial, scheduled for the August 2010, issue is on the design of a digital-to-analog converter (DAC); its quiz was in the last issue. The problem of earthquake prediction (EP) is an important issue for electromagnetics and society, whether or not individuals are interested in it. Electromagnetic (EM) people are right at the center of these discussions, because the majority of these earth quake-prediction claims are based on EM precursors. The part of the community that deals with radars and sensing systems knows very well know that EM-precursor-based earthquake prediction is nothing but a multi-sensor surveillance problem. As mentioned in the last issue, there will be a tutorial on this topic, with a prospec tive title of "Prediction: Extrapolation to the Future," which is tentatively scheduled for the October 2010 issue. Readers who are interested in this topic are referred to [1-3] (and the references therein) for the initial information and potential content of the tuto rial. References I.

Fuel, 1994

... Effect of water vapour on the porous structure of activated carbon from lignite Nartzislav Pe... more ... Effect of water vapour on the porous structure of activated carbon from lignite Nartzislav Petrov, Katia Gergova* and Semih Eser* Chemistry ... The N; surface area and pore size distribution were determined using the BET equation13 and a procedure developed by Barrett et a/.14 ...

Fuel Processing Technology, 2012

Jatropha oil was extracted with hexane from the seeds of a shrub, Jatropha Curcas, in high yields... more Jatropha oil was extracted with hexane from the seeds of a shrub, Jatropha Curcas, in high yields, up to 40% by weight. The extracted oil was converted in a laboratory reactor to biodiesel methyl esters by transesterification with methanol using sodium hydroxide as catalyst. Analysis of Jatropha oil and the produced Jatropha biodiesel by 1 H nuclear magnetic resonance (1 H NMR) showed that Jatropha oil could be readily converted to a biodiesel product through conventional transesterification. 1 H NMR spectroscopy was proven to be a useful tool for monitoring the progress of transesterification reaction to convert Jatropha oil to biodiesel.

Energy & Fuels, 2003

A fluorescence depolarization technique was used to determine the molecular size of asphaltene so... more A fluorescence depolarization technique was used to determine the molecular size of asphaltene solubility fractions of a petroleum resid asphaltene. The molecular size was determined at different emission wavelengths for each solubility fraction. For each subfraction the range of molecular size was found to vary considerably. However, at a given emission wavelength, the molecular sizes for the different asphaltene solubility subfractions are very similar, that is the subfractions differ from each other by different population distributions of the same set of molecules. The size variation among the different subfractions is due to the different molecular population distributions of the constituent components. The population distribution was estimated from published LDMS results.

Energy & Fuels, 2009

The formation of solid carbons by LDPE pyrolysis has been studied in three different reactors: a ... more The formation of solid carbons by LDPE pyrolysis has been studied in three different reactors: a batch feed reactor with slow heating (BFRSH), a batch feed reactor with fast heating (BFRFH), and a semicontinuous feed reactor with fast heating (SFRFH). The yield to solid carbons was low in the batch reactors with slow and fast heating (<3%) even when LDPE was copyrolyzed with polystyrene, lignin, and other additives. The yield increased to values between 15 and 52% when a semicontinuous feed reactor with fast heating was employed, which can be attributed to a longer residence time of primary pyrolysis products and higher extents of condensation reactions. Using a quartz reactor in the semicontinuous feed reaction system produced solid carbons with a homogeneous morphology of monodisperse spherules in high yields (15-43%) at temperatures of 750 and 850°C. A Hastelloy reactor used in the same configuration produced higher yields of solid carbons (33-52%) because of wall catalysis, but the solid carbons obtained included metal alloy particles.

Energy & Fuels, 2007

This study investigates the molecular composition of fluid catalytic cracking (FCC) decant oil an... more This study investigates the molecular composition of fluid catalytic cracking (FCC) decant oil and its derivatives that are used as feedstocks for delayed coking to produce needle coke. Needle coke is a premium solid carbon used in manufacturing graphite electrodes for electric-arc furnace. For the first time in the open literature, this study reports data on the molecular composition of the feed that is actually introduced into the coke drum for delayed coking after fractionating the decant oil feedstock together with the liquid products generated from coking. The coker feed (CF), thus, includes the high-boiling fraction of the decant oil and the high-boiling fraction of liquid products (recycle). Hydrotreated fraction of the decant oil samples (HYD) and a vacuum tower bottom (VTB) obtained from decant oils were also analyzed. More emphasis was placed on analyzing the high-boiling fraction of the feedstocks that is not amenable to gas chromatography. Carbonaceous mesophase development from the feedstocks was also studied to seek relationships between the composition of the feedstocks and the needle coke texture. Commercial FCC decant oil (DO) samples and their derivatives (CF, HYD, and VTB) were carbonized in laboratory reactors. DO samples produced semi-cokes that displayed different degrees of mesophase development and CF, HYD and VTB give a higher degree of mesophase development compared to their parent decant oil. Significant differences were observed in the molecular composition of the different decant oil samples and between the decant oils and their derivatives. The principal compounds found in decant oils and their derivatives were found to consist of 3-to 6-ring PAHs v TABLE OF CONTENTS LIST OF TABLES.

Energy & Fuels, 1997

This study presents the first combined application of 13 C labeling and isotope-ratio-monitoring ... more This study presents the first combined application of 13 C labeling and isotope-ratio-monitoring gas chromatography-mass spectrometry (irmGCMS) to analyze the thermochemical transformations of specific organic compounds within a complex heavy oil. Specifically, this technique was used to monitor the hydrocarbons produced during the carbonization of a fluid catalytic cracking decant oil (FCCDO). Structural GC/MS analysis of these products has previously shown that 4-methyldibenzothiophene, 13 C-labeled at the methyl position (4-13 MDBT), undergoes methylation to form a number of polymethyldibenzothiophenes and cleavage of its aryl-methyl bond to give dibenzothiophene (Energy Fuels 1997, 11, 623, 631). The irmGCMS analysis of these products shows that the 4-13 MDBT is a source of 13 C-enriched methyl that reacts with polyaromatic hydrocarbons (PAH) to produce a number of methylated PAHs. Precise measurement of 13 C enrichment and concentration of specific compounds enables tracking of the labeled carbon within a complex mixture as a function of reaction time. There are large differences in apparent reactivities of mono-and dimethyl-substituted naphthalenes, phenanthrenes, and pyrenes. The differences in observed reactivities of methylnaphthalene, methylphenanthrene, and methylpyrene isomers are consistent with calculated free valence indices at specific positions. There is no significant 13 C enrichment in unsubstituted PAH compounds, indicating that the labeled methyl group is not involved in producing GC-amenable unsubstituted PAH during early carbonization. This combined use of 13 C-labeled reactants and irmGCMS analysis will have broad applications in oil processing and geochemical fields associated with the study of thermochemical transformations of organic compounds within complex mixtures.

Energy & Fuels, 1997

Two decant oils were spiked with 13 C-labeled 4-methyldibenzothiophene (4-13 MDBT) and carbonized... more Two decant oils were spiked with 13 C-labeled 4-methyldibenzothiophene (4-13 MDBT) and carbonized at 500°C to study the reactivity of the 13 C-labeled compound. A quantitative analysis of the reaction product maltenes was performed using GC/MS. The GC/MS was also used to estimate the isotopic enrichment in 13 C of the reaction products. Data shows that demethylation and methylation of 4-MDBT are the principal reactions occurring during the early carbonization of the compound in the decant oils and that the molecular composition of the decant oils is an important factor in determining the extent of these reactions. Incorporation of 4-13 MDBT into the solid phase (semicoke) is, therefore, attributed to an enhanced reactivity due to further alkylation of the molecule.

Petroleum Refining and Natural Gas Processing

Chemical engineering transactions, 2021

Activated carbons (AC) are widely used in a variety of applications because of their controllable... more Activated carbons (AC) are widely used in a variety of applications because of their controllable porosity and surface functionalities. In this work, AC were prepared from different hard woods through one- and two-step pyrolysis/activation for the adsorption of organic pollutants in water. Water vapor was used as the activating agent. The influence of the precursor and preparation methods on the properties of the resulting AC was evaluated through multiple techniques. Temperature-programmed oxidation (TPO) measured the reactivity toward oxygen of chars and AC, while temperature-programmed desorption coupled with mass spectrometry (TPD/MS) revealed functional groups on AC surface. Methylene blue adsorption tests evaluated the adsorption capacity of the prepared AC and the presence of mesopores. Depending on the oxidation reactivity of the char produced by pyrolysis, the resulting AC show different surface composition and adsorption performance. With the increasing char oxidation reac...

... WP-TR-2000-2120 FUEL DEGRADATION AND ALLIED STUDIES DELIVERY ORDER 5 ANDRE BOEHMAN, SEMIH ESE... more ... WP-TR-2000-2120 FUEL DEGRADATION AND ALLIED STUDIES DELIVERY ORDER 5 ANDRE BOEHMAN, SEMIH ESER, PAT ... I PROPULSION DIRECTORATE AIR FORCE RESEARCH LABORATORY AIR FORCE MATERIEL COMMAND WRIGHT-PATTERSON AIR FORCE ...

ACS Symposium Series, 2005

... Semih Eser, Guohua Wang, and Jennifer Clemons ... Hydrotreated samples gave high degrees of m... more ... Semih Eser, Guohua Wang, and Jennifer Clemons ... Hydrotreated samples gave high degrees of mesophase development (OTIs 91 and 93) presumably because of the low rate of carbonization due to the abundance of partially hydrogenated aromatics that act as hydrogen ...

KONA Powder and Particle Journal, 2007

The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and lase... more The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and laser light scattering. Vitrain samples were collected from obvious tree remains located in the ceilings of two Appalachian coal mines. Wet sieving produced narrow size cuts. The particles were determined to be oblong or blocky in shape, with average length-to-width ratio of 1.7 and sphericity of 0.78. They were analogous in shape to a square ended, rectangular "house brick". The two bituminous coals and different size cuts of each coal had essentially the same shape parameters. Characteristic heating times and terminal velocities were higher by 22 and 20%, respectively compared to spherical particles.

Applied Catalysis B: Environmental, 2015

This study analyzes the influence of chemical and physical properties of Pd/C and Pt/C hydrodechl... more This study analyzes the influence of chemical and physical properties of Pd/C and Pt/C hydrodechlorination (HDC) catalysts in the different evolution of their activity during time on stream. Pt/C showed stable activity in the HDC of dichloromethane (DCM) and chloroform (TCM), while Pd/C was deactivated after 90 hours of operation, particularly during HDC of DCM. The deactivation of Pd/C catalyst can be attributed to the lower proportion of zero-valent species and larger metal particle size. This appears to hinder the H 2 dissociation, enhance the irreversible chemisorption of reactants and reaction products, and favor coupling reactions (leading to the formation of carbonaceous deposits) and/or metal phase change reactions. The more extensive deactivation of Pd/C in the HDC of DCM is attributed to the stronger chemisorption of the reactant on the catalyst, which leads to the formation of a new PdC x phase by the incorporation of carbon atoms into the metal lattice.

Task 1: Investigation of the Quantitative Degradation Chemistry of Fuels.

Springer Series in Materials Science, 1998

... Page 172. 152 Semih Eser Figure 3 shows a plot of the concentrations of the six groups of com... more ... Page 172. 152 Semih Eser Figure 3 shows a plot of the concentrations of the six groups of com-pounds identified in the second set of decant oil and thermal tar samples. ... Solid State Chem. 9. 59 (1974) 8. H. Marsh, PL Walker. ...

Industrial & Engineering Chemistry Research, 2010

IEEE Antennas and Propagation Magazine, 2010

O pen-area test site (OATS) calibration is a fundamental antenna-engineering task. This issue's t... more O pen-area test site (OATS) calibration is a fundamental antenna-engineering task. This issue's tutorial is on the cali bration of an open-area test site. The requirements, the theoretical basis, related standards, and the procedure to be followed are dis cussed in this tutorial. The next tutorial, scheduled for the August 2010, issue is on the design of a digital-to-analog converter (DAC); its quiz was in the last issue. The problem of earthquake prediction (EP) is an important issue for electromagnetics and society, whether or not individuals are interested in it. Electromagnetic (EM) people are right at the center of these discussions, because the majority of these earth quake-prediction claims are based on EM precursors. The part of the community that deals with radars and sensing systems knows very well know that EM-precursor-based earthquake prediction is nothing but a multi-sensor surveillance problem. As mentioned in the last issue, there will be a tutorial on this topic, with a prospec tive title of "Prediction: Extrapolation to the Future," which is tentatively scheduled for the October 2010 issue. Readers who are interested in this topic are referred to [1-3] (and the references therein) for the initial information and potential content of the tuto rial. References I.

Fuel, 1994

... Effect of water vapour on the porous structure of activated carbon from lignite Nartzislav Pe... more ... Effect of water vapour on the porous structure of activated carbon from lignite Nartzislav Petrov, Katia Gergova* and Semih Eser* Chemistry ... The N; surface area and pore size distribution were determined using the BET equation13 and a procedure developed by Barrett et a/.14 ...

Fuel Processing Technology, 2012

Jatropha oil was extracted with hexane from the seeds of a shrub, Jatropha Curcas, in high yields... more Jatropha oil was extracted with hexane from the seeds of a shrub, Jatropha Curcas, in high yields, up to 40% by weight. The extracted oil was converted in a laboratory reactor to biodiesel methyl esters by transesterification with methanol using sodium hydroxide as catalyst. Analysis of Jatropha oil and the produced Jatropha biodiesel by 1 H nuclear magnetic resonance (1 H NMR) showed that Jatropha oil could be readily converted to a biodiesel product through conventional transesterification. 1 H NMR spectroscopy was proven to be a useful tool for monitoring the progress of transesterification reaction to convert Jatropha oil to biodiesel.

Energy & Fuels, 2003

A fluorescence depolarization technique was used to determine the molecular size of asphaltene so... more A fluorescence depolarization technique was used to determine the molecular size of asphaltene solubility fractions of a petroleum resid asphaltene. The molecular size was determined at different emission wavelengths for each solubility fraction. For each subfraction the range of molecular size was found to vary considerably. However, at a given emission wavelength, the molecular sizes for the different asphaltene solubility subfractions are very similar, that is the subfractions differ from each other by different population distributions of the same set of molecules. The size variation among the different subfractions is due to the different molecular population distributions of the constituent components. The population distribution was estimated from published LDMS results.

Energy & Fuels, 2009

The formation of solid carbons by LDPE pyrolysis has been studied in three different reactors: a ... more The formation of solid carbons by LDPE pyrolysis has been studied in three different reactors: a batch feed reactor with slow heating (BFRSH), a batch feed reactor with fast heating (BFRFH), and a semicontinuous feed reactor with fast heating (SFRFH). The yield to solid carbons was low in the batch reactors with slow and fast heating (<3%) even when LDPE was copyrolyzed with polystyrene, lignin, and other additives. The yield increased to values between 15 and 52% when a semicontinuous feed reactor with fast heating was employed, which can be attributed to a longer residence time of primary pyrolysis products and higher extents of condensation reactions. Using a quartz reactor in the semicontinuous feed reaction system produced solid carbons with a homogeneous morphology of monodisperse spherules in high yields (15-43%) at temperatures of 750 and 850°C. A Hastelloy reactor used in the same configuration produced higher yields of solid carbons (33-52%) because of wall catalysis, but the solid carbons obtained included metal alloy particles.

Energy & Fuels, 2007

This study investigates the molecular composition of fluid catalytic cracking (FCC) decant oil an... more This study investigates the molecular composition of fluid catalytic cracking (FCC) decant oil and its derivatives that are used as feedstocks for delayed coking to produce needle coke. Needle coke is a premium solid carbon used in manufacturing graphite electrodes for electric-arc furnace. For the first time in the open literature, this study reports data on the molecular composition of the feed that is actually introduced into the coke drum for delayed coking after fractionating the decant oil feedstock together with the liquid products generated from coking. The coker feed (CF), thus, includes the high-boiling fraction of the decant oil and the high-boiling fraction of liquid products (recycle). Hydrotreated fraction of the decant oil samples (HYD) and a vacuum tower bottom (VTB) obtained from decant oils were also analyzed. More emphasis was placed on analyzing the high-boiling fraction of the feedstocks that is not amenable to gas chromatography. Carbonaceous mesophase development from the feedstocks was also studied to seek relationships between the composition of the feedstocks and the needle coke texture. Commercial FCC decant oil (DO) samples and their derivatives (CF, HYD, and VTB) were carbonized in laboratory reactors. DO samples produced semi-cokes that displayed different degrees of mesophase development and CF, HYD and VTB give a higher degree of mesophase development compared to their parent decant oil. Significant differences were observed in the molecular composition of the different decant oil samples and between the decant oils and their derivatives. The principal compounds found in decant oils and their derivatives were found to consist of 3-to 6-ring PAHs v TABLE OF CONTENTS LIST OF TABLES.

Energy & Fuels, 1997

This study presents the first combined application of 13 C labeling and isotope-ratio-monitoring ... more This study presents the first combined application of 13 C labeling and isotope-ratio-monitoring gas chromatography-mass spectrometry (irmGCMS) to analyze the thermochemical transformations of specific organic compounds within a complex heavy oil. Specifically, this technique was used to monitor the hydrocarbons produced during the carbonization of a fluid catalytic cracking decant oil (FCCDO). Structural GC/MS analysis of these products has previously shown that 4-methyldibenzothiophene, 13 C-labeled at the methyl position (4-13 MDBT), undergoes methylation to form a number of polymethyldibenzothiophenes and cleavage of its aryl-methyl bond to give dibenzothiophene (Energy Fuels 1997, 11, 623, 631). The irmGCMS analysis of these products shows that the 4-13 MDBT is a source of 13 C-enriched methyl that reacts with polyaromatic hydrocarbons (PAH) to produce a number of methylated PAHs. Precise measurement of 13 C enrichment and concentration of specific compounds enables tracking of the labeled carbon within a complex mixture as a function of reaction time. There are large differences in apparent reactivities of mono-and dimethyl-substituted naphthalenes, phenanthrenes, and pyrenes. The differences in observed reactivities of methylnaphthalene, methylphenanthrene, and methylpyrene isomers are consistent with calculated free valence indices at specific positions. There is no significant 13 C enrichment in unsubstituted PAH compounds, indicating that the labeled methyl group is not involved in producing GC-amenable unsubstituted PAH during early carbonization. This combined use of 13 C-labeled reactants and irmGCMS analysis will have broad applications in oil processing and geochemical fields associated with the study of thermochemical transformations of organic compounds within complex mixtures.

Energy & Fuels, 1997

Two decant oils were spiked with 13 C-labeled 4-methyldibenzothiophene (4-13 MDBT) and carbonized... more Two decant oils were spiked with 13 C-labeled 4-methyldibenzothiophene (4-13 MDBT) and carbonized at 500°C to study the reactivity of the 13 C-labeled compound. A quantitative analysis of the reaction product maltenes was performed using GC/MS. The GC/MS was also used to estimate the isotopic enrichment in 13 C of the reaction products. Data shows that demethylation and methylation of 4-MDBT are the principal reactions occurring during the early carbonization of the compound in the decant oils and that the molecular composition of the decant oils is an important factor in determining the extent of these reactions. Incorporation of 4-13 MDBT into the solid phase (semicoke) is, therefore, attributed to an enhanced reactivity due to further alkylation of the molecule.