Abdullah Aitani | King Fahd University of Petroleum and Minerals (original) (raw)
Papers by Abdullah Aitani
Catalysis Letters, 2020
Infrared spectra of dealuminated high silica MFI zeolites were measured to elucidate the structur... more Infrared spectra of dealuminated high silica MFI zeolites were measured to elucidate the structure of silanol groups active for conversion of 1-butene to propene. The OH groups were replaced by OD groups to have clear vibrational spectra. Two sharp bands and one broad band were observed; isolated silanol at 2746 cm −1 , terminal silanol at 2725 cm −1 , and hydrogen-bonded silanols centered at 2570 cm −1 composed of more than one components. Based on the response of these bands to Na poisoning and pyridine adsorption together with the correlation with catalytic results, we propose that the active sites for propene formation are one of the terminal silanol groups and one of the hydrogen-bonded silanol groups in a silanol nest. The active hydrogen-bonded silanol groups are the one whose O atom is hydrogen-bonded to adjacent two H atoms in the silanol nest.
Journal of Industrial and Engineering Chemistry, 2021
Hierarchical composites of MCM-41 on zeolite Beta were synthesized by in-situ hydrothermal techni... more Hierarchical composites of MCM-41 on zeolite Beta were synthesized by in-situ hydrothermal technique, characterized and their catalytic performance for converting heavy reformate into valuable xylenes was evaluated. Systematic optimization of the hierarchical pore generation was carried out by varying the strength of the alkaline solution (0.10À0.45 M NaOH) during disintegration of zeolite Beta. The nanocomposites obtained were extruded with alumina binder and impregnated with 4.0 wt% Mo. The characterization results indicate the transition of mesophase occurs from distinct disordered phase to ordered/disordered and then to ordered mesophase with increasing alkaline concentration. The xylene yield over the hierarchical composite zeolite was 1.4 times more than the parent zeolite Beta. Incorporation of a well-dispersed mild hydrogenation function (4 wt.% Mo) was advantageous in improving the xylene yield and selectivity. The formulation prepared with moderately alkaline (0.2 M NaOH) solution exhibited optimum bimodal pore structure and improved dealkylation and transalkylation conversion resulting in a xylene yield of 33.0 wt.% and 1.7 times enhancement in xylene selectivity over parent zeolite Beta. A 30 h stability test showed steady performance and xylene yields. Hence, a potential application of hierarchical zeolite Beta and MCM-41 composite catalysts for the conversion of heavy aromatics to produce xylenes has been successfully demonstrated.
Journal of Analytical and Applied Pyrolysis, 2020
The catalytic and thermal cracking of three types of whole crude oils, having API gravity at 34°(... more The catalytic and thermal cracking of three types of whole crude oils, having API gravity at 34°(AL), 39°(AXL) and 51°(ASL), were investigated via a fixed-bed micro-activity test (MAT) unit at high temperature between 600 and 650°C. Equilibrium FCC catalyst (E-Cat)/ZSM-5 additive was used for catalytic cracking tests at 30 s and catalyst/oil (C/O) ratio of 2.0-6.0. For both thermal and catalytic cracking of all crude oils, the increase in reaction temperature resulted in higher conversion and enhanced yields of C 2-C 4 light olefins, LPG, coke, and dry gas at the expense of naphtha, heavy cycle oil (HCO), and light cycle oil (LCO). In thermal cracking, the yields of C 2-C 4 olefins at 650°C were as follows: AL (22.8 wt.%) > AXL (19.0 wt.%) > ASL (18.8 wt.%) associated with naphtha yields of 34.4, 38.1 and 48.0 wt.%, respectively. Compared with thermal, catalytic cracking over E-Cat/ ZSM-5 enhanced conversion, doubled the yields of light olefins and showed an increase in aromatics content of naphtha fraction. Contrary to thermal cracking, the yields of C 2-C 4 olefins in catalytic cracking were as follows: ASL (42.9 wt.%) > AXL (41 wt.%) > AL (39.1 wt.%) associated with naphtha yields of 31.7, 27.5, and 23.0 wt. %, respectively.
ChemistrySelect, 2021
The literature on catalytic and mechanistic aspects of the sidechain alkenylation of toluene with... more The literature on catalytic and mechanistic aspects of the sidechain alkenylation of toluene with methanol for the formation of styrene on solid base catalysts is reviewed. The development of catalysts and catalysis are described mostly on alkali ion exchange zeolite catalysts with fundamental chemistry related to the side-chain alkenylation. Mechanistic studies performed from various viewpoints are described. Methods to elucidate the reaction mechanisms are discussed based on the identification of the adsorbed species of the reactants, use of plausible intermediate compounds as reactant, characterization of surface properties to examine the correlation with reaction results, poisoning of the active sites by certain molecules, and theoretical calculations of the energy profile along with the reaction coordinate. These studies are discussed with critical assessments. The review addresses several challenges that prevent the side-chain alkenylation of toluene with methanol from industrialization which include decomposition of methanol to CO and H 2, and co-production of ethylbenzene. The paper covers mostly literature published during the period from 2000 to early 2021.
Chemisrtyselect, 2020
We investigated the conversion of light paraffinic naphtha (C5-C6) into BTX (benzene, toluene, an... more We investigated the conversion of light paraffinic naphtha (C5-C6) into BTX (benzene, toluene, and xylenes) aromatics using 1.0 wt % Pt-M/ZSM-5 (modifier M = 1 wt% Zn, 2 wt % of Fe, La, Ga) prepared using wet-impregnation method. The effects of Pt and modifier on light naphtha conversion, yield and aromatic selectivity (benzene, toluene, xylene, C9 + aromatics) were studied in fixed-bed flow reactor in atmospheric pressure, at 550°C, and WHSV 1.0 h À 1. Catalytic efficiency of modified Pt or Pt-M ZSM-5 catalysts has been equated to conventional ZSM-5 [Si/Al 2 = 30] catalyst. While the yield of total aromatics was slightly increased over Pt/ZSM-5 comparison to parent ZSM-5 from 32 wt % to 37 wt %, the value for in situ formed mesoporous Pt-Ga/ZSM-5 was significantly improved reaching 60 wt %. The higher selectivity to aromatics is attributed to the induced mesoporous volumes and dehydrogenation activity of Ga species. These species associated with Pt were effective in the conversion of light naphtha to olefins, which later converted into aromatics by secondary reactions: cracking, isomerization and dimerization. The Pt-Ga/ZSM-5 showed good stability toward the selective production of aromatics at a low toluene/benzene ratio ∼ 0.5 due to Pt component.
Hydrogen Science and Engineering : Materials, Processes, Systems and Technology, 2016
Plasmas, both thermal and non-thermal, have been studied for the conversion of gaseous and liquid... more Plasmas, both thermal and non-thermal, have been studied for the conversion of gaseous and liquid hydrocarbons into hydrogen. Plasma systems such as gliding-arc, microwave, corona, dielectric barrier discharge, arc plasma-jet, radio frequency, and other types of plasmas with or without catalysts have shown potential for the production of hydrogen. Various reactor configurations and operating conditions have been investigated to perform plasma-based hydrocarbon reactions such as steam reforming, dry auto-thermal reforming, partial oxidation, or decomposition (pyrolysis) processes. The combination of these processes in a hybrid plasma–catalytic system has also been discussed.
Energy & Fuels, 2019
The upgrading of light naphtha (C5–C6 stream) to gasoline blending components has been the subjec... more The upgrading of light naphtha (C5–C6 stream) to gasoline blending components has been the subject of intensive research at both academic and industrial laboratories. The combination of high volatility and low-octane number has made this stream surplus at many refineries worldwide. This review presents the latest developments in selected catalytic upgrading processes and a brief discussion on the reaction mechanism and reactor models. A majority of the review falls within the development of catalysts for n-hexane isomerization to hydrocarbon isomers with a high octane number. There are three types of isomerization catalysts that include Pt/Al2O3–Cl, Pt/SO4–ZrO2, and Pt/zeolite. Efforts are ongoing to improve the catalyst performance for higher selectivity and catalyst lifetime. Very little work has been published on the conversion of n-pentane mainly as a result of its low activity and the limited options available for its transformation to gasoline blending components. Other approaches discussed in the review include dimerization and oligomerization of C5–C6 alkenes and methylative homologation. The review covers literature published during the period of 2000–2018.
Energy & Fuels, 2018
The catalytic cracking of light paraffinic crude oil with an API gravity of 51° was compared usin... more The catalytic cracking of light paraffinic crude oil with an API gravity of 51° was compared using two laboratory testing techniques, a fixed-bed microactivity test (MAT) unit and a fixed fluidized-bed advanced cracking evaluation (ACE) unit. Both units were operated using equilibrated FCC catalyst (E-Cat), MFI zeolite (ZSM-5), and E-Cat/MFI (equal mixture with MFI) at two temperatures (550 and 600 °C) and a constant catalyst-to-oil ratio of 4.0. Despite the different hydrodynamics in MAT and ACE reactors, both units gave similar catalyst ranking based on the conversion of 221+ °C feed fraction at 550 and 600 °C in the order of E-Cat > E-Cat/MFI > MFI, which is attributed to diffusion limitation of MFI catalyst. While both testing techniques showed variation in product yield structure (dry gas, LPG, naphtha, and unconverted 221+ °C) over the three catalysts, the ACE unit gave significantly higher coke yield compared with MAT. The highest yield of light olefins was obtained over E-Cat/MFI (29 wt %) at 600 °C in MAT compared with MFI (23 wt %) and E-Cat (21 wt %). The effect of high temperature (650 °C) on crude oil cracking in ACE showed an increase in conversion and light olefins yield for all catalysts as well as in thermal cracking case (no catalyst) associated with a decrease in naphtha yield. The highest yields of light olefins (35 wt%) was obtained at a naphtha yield of 37 wt % over E-Cat/MFI compared with 30 and 41 wt %, respectively, for no catalyst. However, the operation at high temperature introduced the adverse effects of thermal cracking resulting in high yields of dry gas (14 wt % for E-Cat and 17 wt % for no-catalyst), which reflects a significant contribution of pyrolytic cracking reactions.
Energy & Fuels, 2017
The direct catalytic cracking of Arab Extra Light (AXL) crude oil was conducted in a microactivit... more The direct catalytic cracking of Arab Extra Light (AXL) crude oil was conducted in a microactivity test (MAT) unit at 550 °C, where product recycling was simulated by mixing feed and liquid products in varying proportions. The effect of AXL mixing with total liquid product (LP) or a mixture of light cycle oil (LCO) and heavy cycle oil (HCO) was investigated at various ratios to determine the dependence of light olefins yield on feed composition. It was observed that mixing the least amount of LP with AXL yielded ∼20.3 wt % light olefins and 39.6 wt % naphtha. The cracking of AXL and LCO+HCO yielded similar results as the case of cracking LP. A configuration of 100% recycle of liquid product without blending with AXL feed showed an increase in the yield of light olefins from 20 wt % to 29 wt % associated with a decrease in naphtha yield from 40 wt % to 27 wt %. A second configuration of 100% recycle of LCO+HCO without blending with AXL feed showed that the yield of light olefins increased from 20 wt % to 26 wt % associated with an increase in naphtha yield from 40 wt % to 50 wt %. The study has shown that the recycling of low-value heavy fraction (LCO+HCO) is a cost-effective means to supplement the AXL feed without loss in the yield of desired light olefins and naphtha.
Chemical Engineering Journal, 2016
Ethyltoluenes (ET) synthesis via different alkylation routes; toluene with ethanol and ethylbenze... more Ethyltoluenes (ET) synthesis via different alkylation routes; toluene with ethanol and ethylbenzene (EB) with methanol, was investigated over zeolites with three-dimensional (3D) pore system i.e. SSZ-33, TNU-9, ZSM-5, IM-5, and one-dimensional zeolite MOR in a fluidized-bed reactor in the temperature range 250–350 °C for reaction times of 5–20 s. Alkylation of toluene with ethanol provided higher yields and selectivities to ethyltoluenes over all zeolites. The maximum ET yield achieved for toluene ethylation was 13.7 wt.% using IM-5 and ZSM-5 whereas 12.5 wt.% was obtained in EB methylation over SSZ-33. SSZ-33 provided the highest ET-selectivity of ∼50% due to the combine effect of its 3D topology and 12-ring channels. In contrast to ET selectivity, p-ethyltoluene selectivity was almost the same, ∼26%, irrespective of the zeolite topology. Kinetic studies of toluene ethylation over the zeolites were conducted using power law coupled with time-on-stream deactivation model. A satisfactory correlation between experimental data and the model result was achieved. The activation energy of the various zeolites used for the alkylation of toluene to ET decreased in the order: IM-5 (58.2 kJ/mol) > SSZ-33 (39.7 kJ/mol) > TNU-9 (27.3 kJ/mol) > MOR (20.2 kJ/mol) > ZSM-5 (17.0 kJ/mol) which was explained by different acid strength and nature of the zeolites.
Petroleum Science and Technology, Mar 1, 2007
ABSTRACT This review covers publications in the open literature and patents issued during the las... more ABSTRACT This review covers publications in the open literature and patents issued during the last 10 years on issues related to fluid catalytic cracking (FCC) gasoline sulfur reduction. Emphasis was placed on FCC additives, their composition and performance. An attempt was made to elucidate the mechanism for sulfur reduction at FCC cracking conditions. Fluid catalytic cracking technology advances, both process and catalyst, have historically worked together to achieve significant improvements in FCC performance. There is every reason to expect that this will continue to be the case in the future. These advances will have an impact on the volume and quality of the FCC gasoline produced and will offer additional operating flexibility.
Oil and Gas Journal, Sep 26, 2005
ABSTRACT
Arabian Journal Science & Engineering , 1996
Available methods to reduce the amt. of refinery residues by phys. sepn., carbon rejection, or hy... more Available methods to reduce the amt. of refinery residues by phys. sepn., carbon rejection, or hydrogen addn., produce heavier residues of their own that need to be utilized or disposed of. One alternative that totally converts the residue and at the same time complies with environmental restraints is the gasification or partial oxidn. process. Practically, all types of refinery high-sulfur heavy residues may be utilized to produce hydrogen, syngas, or power. This study briefly describes the gasification process for heavy residues and com. projects in its application in refinery power generation. The economics of three options, namely, for hydrogen prodn., for power generation, and for coprodn. of hydrogen, power, and syngas, are examd. and compared. All three options provide reasonable payback periods of 3.3, 4.7, and 4.9 yr, resp. However, each refinery must det. its own needs and export potential in its configuration for coprodn. and final implementation of heavy residue gasification.
Applied Catalysis A: General, 2016
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, 1996
The purpose of this paper is to review recent studies on catalytic conversion of benzene in refo... more The purpose of this paper is to review recent studies on catalytic conversion of
benzene in reformate by hydrogenation, hydroisomerization, and alkylation.
Refineries throughout the world are facing challenges in meeting new fuel
specifications; one of them is benzene content in motor gasoline. Almost all the
proposed benzene reduction processes are within the naphtha processing area,
since the reformate is the major source of benzene (typically in the range 2.5-8.0
vol.%), as well as the major component in the gasoline pool. The catalytic
conversion approach discussed in this paper is the most flexible one since it allows
accurate monitoring of the benzene without altering the operation of the reformer
unit. The present paper also briefly compares the costs of various benzene
reduction options and their impact on refinery economics.
Catalysis Letters, 2020
Infrared spectra of dealuminated high silica MFI zeolites were measured to elucidate the structur... more Infrared spectra of dealuminated high silica MFI zeolites were measured to elucidate the structure of silanol groups active for conversion of 1-butene to propene. The OH groups were replaced by OD groups to have clear vibrational spectra. Two sharp bands and one broad band were observed; isolated silanol at 2746 cm −1 , terminal silanol at 2725 cm −1 , and hydrogen-bonded silanols centered at 2570 cm −1 composed of more than one components. Based on the response of these bands to Na poisoning and pyridine adsorption together with the correlation with catalytic results, we propose that the active sites for propene formation are one of the terminal silanol groups and one of the hydrogen-bonded silanol groups in a silanol nest. The active hydrogen-bonded silanol groups are the one whose O atom is hydrogen-bonded to adjacent two H atoms in the silanol nest.
Journal of Industrial and Engineering Chemistry, 2021
Hierarchical composites of MCM-41 on zeolite Beta were synthesized by in-situ hydrothermal techni... more Hierarchical composites of MCM-41 on zeolite Beta were synthesized by in-situ hydrothermal technique, characterized and their catalytic performance for converting heavy reformate into valuable xylenes was evaluated. Systematic optimization of the hierarchical pore generation was carried out by varying the strength of the alkaline solution (0.10À0.45 M NaOH) during disintegration of zeolite Beta. The nanocomposites obtained were extruded with alumina binder and impregnated with 4.0 wt% Mo. The characterization results indicate the transition of mesophase occurs from distinct disordered phase to ordered/disordered and then to ordered mesophase with increasing alkaline concentration. The xylene yield over the hierarchical composite zeolite was 1.4 times more than the parent zeolite Beta. Incorporation of a well-dispersed mild hydrogenation function (4 wt.% Mo) was advantageous in improving the xylene yield and selectivity. The formulation prepared with moderately alkaline (0.2 M NaOH) solution exhibited optimum bimodal pore structure and improved dealkylation and transalkylation conversion resulting in a xylene yield of 33.0 wt.% and 1.7 times enhancement in xylene selectivity over parent zeolite Beta. A 30 h stability test showed steady performance and xylene yields. Hence, a potential application of hierarchical zeolite Beta and MCM-41 composite catalysts for the conversion of heavy aromatics to produce xylenes has been successfully demonstrated.
Journal of Analytical and Applied Pyrolysis, 2020
The catalytic and thermal cracking of three types of whole crude oils, having API gravity at 34°(... more The catalytic and thermal cracking of three types of whole crude oils, having API gravity at 34°(AL), 39°(AXL) and 51°(ASL), were investigated via a fixed-bed micro-activity test (MAT) unit at high temperature between 600 and 650°C. Equilibrium FCC catalyst (E-Cat)/ZSM-5 additive was used for catalytic cracking tests at 30 s and catalyst/oil (C/O) ratio of 2.0-6.0. For both thermal and catalytic cracking of all crude oils, the increase in reaction temperature resulted in higher conversion and enhanced yields of C 2-C 4 light olefins, LPG, coke, and dry gas at the expense of naphtha, heavy cycle oil (HCO), and light cycle oil (LCO). In thermal cracking, the yields of C 2-C 4 olefins at 650°C were as follows: AL (22.8 wt.%) > AXL (19.0 wt.%) > ASL (18.8 wt.%) associated with naphtha yields of 34.4, 38.1 and 48.0 wt.%, respectively. Compared with thermal, catalytic cracking over E-Cat/ ZSM-5 enhanced conversion, doubled the yields of light olefins and showed an increase in aromatics content of naphtha fraction. Contrary to thermal cracking, the yields of C 2-C 4 olefins in catalytic cracking were as follows: ASL (42.9 wt.%) > AXL (41 wt.%) > AL (39.1 wt.%) associated with naphtha yields of 31.7, 27.5, and 23.0 wt. %, respectively.
ChemistrySelect, 2021
The literature on catalytic and mechanistic aspects of the sidechain alkenylation of toluene with... more The literature on catalytic and mechanistic aspects of the sidechain alkenylation of toluene with methanol for the formation of styrene on solid base catalysts is reviewed. The development of catalysts and catalysis are described mostly on alkali ion exchange zeolite catalysts with fundamental chemistry related to the side-chain alkenylation. Mechanistic studies performed from various viewpoints are described. Methods to elucidate the reaction mechanisms are discussed based on the identification of the adsorbed species of the reactants, use of plausible intermediate compounds as reactant, characterization of surface properties to examine the correlation with reaction results, poisoning of the active sites by certain molecules, and theoretical calculations of the energy profile along with the reaction coordinate. These studies are discussed with critical assessments. The review addresses several challenges that prevent the side-chain alkenylation of toluene with methanol from industrialization which include decomposition of methanol to CO and H 2, and co-production of ethylbenzene. The paper covers mostly literature published during the period from 2000 to early 2021.
Chemisrtyselect, 2020
We investigated the conversion of light paraffinic naphtha (C5-C6) into BTX (benzene, toluene, an... more We investigated the conversion of light paraffinic naphtha (C5-C6) into BTX (benzene, toluene, and xylenes) aromatics using 1.0 wt % Pt-M/ZSM-5 (modifier M = 1 wt% Zn, 2 wt % of Fe, La, Ga) prepared using wet-impregnation method. The effects of Pt and modifier on light naphtha conversion, yield and aromatic selectivity (benzene, toluene, xylene, C9 + aromatics) were studied in fixed-bed flow reactor in atmospheric pressure, at 550°C, and WHSV 1.0 h À 1. Catalytic efficiency of modified Pt or Pt-M ZSM-5 catalysts has been equated to conventional ZSM-5 [Si/Al 2 = 30] catalyst. While the yield of total aromatics was slightly increased over Pt/ZSM-5 comparison to parent ZSM-5 from 32 wt % to 37 wt %, the value for in situ formed mesoporous Pt-Ga/ZSM-5 was significantly improved reaching 60 wt %. The higher selectivity to aromatics is attributed to the induced mesoporous volumes and dehydrogenation activity of Ga species. These species associated with Pt were effective in the conversion of light naphtha to olefins, which later converted into aromatics by secondary reactions: cracking, isomerization and dimerization. The Pt-Ga/ZSM-5 showed good stability toward the selective production of aromatics at a low toluene/benzene ratio ∼ 0.5 due to Pt component.
Hydrogen Science and Engineering : Materials, Processes, Systems and Technology, 2016
Plasmas, both thermal and non-thermal, have been studied for the conversion of gaseous and liquid... more Plasmas, both thermal and non-thermal, have been studied for the conversion of gaseous and liquid hydrocarbons into hydrogen. Plasma systems such as gliding-arc, microwave, corona, dielectric barrier discharge, arc plasma-jet, radio frequency, and other types of plasmas with or without catalysts have shown potential for the production of hydrogen. Various reactor configurations and operating conditions have been investigated to perform plasma-based hydrocarbon reactions such as steam reforming, dry auto-thermal reforming, partial oxidation, or decomposition (pyrolysis) processes. The combination of these processes in a hybrid plasma–catalytic system has also been discussed.
Energy & Fuels, 2019
The upgrading of light naphtha (C5–C6 stream) to gasoline blending components has been the subjec... more The upgrading of light naphtha (C5–C6 stream) to gasoline blending components has been the subject of intensive research at both academic and industrial laboratories. The combination of high volatility and low-octane number has made this stream surplus at many refineries worldwide. This review presents the latest developments in selected catalytic upgrading processes and a brief discussion on the reaction mechanism and reactor models. A majority of the review falls within the development of catalysts for n-hexane isomerization to hydrocarbon isomers with a high octane number. There are three types of isomerization catalysts that include Pt/Al2O3–Cl, Pt/SO4–ZrO2, and Pt/zeolite. Efforts are ongoing to improve the catalyst performance for higher selectivity and catalyst lifetime. Very little work has been published on the conversion of n-pentane mainly as a result of its low activity and the limited options available for its transformation to gasoline blending components. Other approaches discussed in the review include dimerization and oligomerization of C5–C6 alkenes and methylative homologation. The review covers literature published during the period of 2000–2018.
Energy & Fuels, 2018
The catalytic cracking of light paraffinic crude oil with an API gravity of 51° was compared usin... more The catalytic cracking of light paraffinic crude oil with an API gravity of 51° was compared using two laboratory testing techniques, a fixed-bed microactivity test (MAT) unit and a fixed fluidized-bed advanced cracking evaluation (ACE) unit. Both units were operated using equilibrated FCC catalyst (E-Cat), MFI zeolite (ZSM-5), and E-Cat/MFI (equal mixture with MFI) at two temperatures (550 and 600 °C) and a constant catalyst-to-oil ratio of 4.0. Despite the different hydrodynamics in MAT and ACE reactors, both units gave similar catalyst ranking based on the conversion of 221+ °C feed fraction at 550 and 600 °C in the order of E-Cat > E-Cat/MFI > MFI, which is attributed to diffusion limitation of MFI catalyst. While both testing techniques showed variation in product yield structure (dry gas, LPG, naphtha, and unconverted 221+ °C) over the three catalysts, the ACE unit gave significantly higher coke yield compared with MAT. The highest yield of light olefins was obtained over E-Cat/MFI (29 wt %) at 600 °C in MAT compared with MFI (23 wt %) and E-Cat (21 wt %). The effect of high temperature (650 °C) on crude oil cracking in ACE showed an increase in conversion and light olefins yield for all catalysts as well as in thermal cracking case (no catalyst) associated with a decrease in naphtha yield. The highest yields of light olefins (35 wt%) was obtained at a naphtha yield of 37 wt % over E-Cat/MFI compared with 30 and 41 wt %, respectively, for no catalyst. However, the operation at high temperature introduced the adverse effects of thermal cracking resulting in high yields of dry gas (14 wt % for E-Cat and 17 wt % for no-catalyst), which reflects a significant contribution of pyrolytic cracking reactions.
Energy & Fuels, 2017
The direct catalytic cracking of Arab Extra Light (AXL) crude oil was conducted in a microactivit... more The direct catalytic cracking of Arab Extra Light (AXL) crude oil was conducted in a microactivity test (MAT) unit at 550 °C, where product recycling was simulated by mixing feed and liquid products in varying proportions. The effect of AXL mixing with total liquid product (LP) or a mixture of light cycle oil (LCO) and heavy cycle oil (HCO) was investigated at various ratios to determine the dependence of light olefins yield on feed composition. It was observed that mixing the least amount of LP with AXL yielded ∼20.3 wt % light olefins and 39.6 wt % naphtha. The cracking of AXL and LCO+HCO yielded similar results as the case of cracking LP. A configuration of 100% recycle of liquid product without blending with AXL feed showed an increase in the yield of light olefins from 20 wt % to 29 wt % associated with a decrease in naphtha yield from 40 wt % to 27 wt %. A second configuration of 100% recycle of LCO+HCO without blending with AXL feed showed that the yield of light olefins increased from 20 wt % to 26 wt % associated with an increase in naphtha yield from 40 wt % to 50 wt %. The study has shown that the recycling of low-value heavy fraction (LCO+HCO) is a cost-effective means to supplement the AXL feed without loss in the yield of desired light olefins and naphtha.
Chemical Engineering Journal, 2016
Ethyltoluenes (ET) synthesis via different alkylation routes; toluene with ethanol and ethylbenze... more Ethyltoluenes (ET) synthesis via different alkylation routes; toluene with ethanol and ethylbenzene (EB) with methanol, was investigated over zeolites with three-dimensional (3D) pore system i.e. SSZ-33, TNU-9, ZSM-5, IM-5, and one-dimensional zeolite MOR in a fluidized-bed reactor in the temperature range 250–350 °C for reaction times of 5–20 s. Alkylation of toluene with ethanol provided higher yields and selectivities to ethyltoluenes over all zeolites. The maximum ET yield achieved for toluene ethylation was 13.7 wt.% using IM-5 and ZSM-5 whereas 12.5 wt.% was obtained in EB methylation over SSZ-33. SSZ-33 provided the highest ET-selectivity of ∼50% due to the combine effect of its 3D topology and 12-ring channels. In contrast to ET selectivity, p-ethyltoluene selectivity was almost the same, ∼26%, irrespective of the zeolite topology. Kinetic studies of toluene ethylation over the zeolites were conducted using power law coupled with time-on-stream deactivation model. A satisfactory correlation between experimental data and the model result was achieved. The activation energy of the various zeolites used for the alkylation of toluene to ET decreased in the order: IM-5 (58.2 kJ/mol) > SSZ-33 (39.7 kJ/mol) > TNU-9 (27.3 kJ/mol) > MOR (20.2 kJ/mol) > ZSM-5 (17.0 kJ/mol) which was explained by different acid strength and nature of the zeolites.
Petroleum Science and Technology, Mar 1, 2007
ABSTRACT This review covers publications in the open literature and patents issued during the las... more ABSTRACT This review covers publications in the open literature and patents issued during the last 10 years on issues related to fluid catalytic cracking (FCC) gasoline sulfur reduction. Emphasis was placed on FCC additives, their composition and performance. An attempt was made to elucidate the mechanism for sulfur reduction at FCC cracking conditions. Fluid catalytic cracking technology advances, both process and catalyst, have historically worked together to achieve significant improvements in FCC performance. There is every reason to expect that this will continue to be the case in the future. These advances will have an impact on the volume and quality of the FCC gasoline produced and will offer additional operating flexibility.
Oil and Gas Journal, Sep 26, 2005
ABSTRACT
Arabian Journal Science & Engineering , 1996
Available methods to reduce the amt. of refinery residues by phys. sepn., carbon rejection, or hy... more Available methods to reduce the amt. of refinery residues by phys. sepn., carbon rejection, or hydrogen addn., produce heavier residues of their own that need to be utilized or disposed of. One alternative that totally converts the residue and at the same time complies with environmental restraints is the gasification or partial oxidn. process. Practically, all types of refinery high-sulfur heavy residues may be utilized to produce hydrogen, syngas, or power. This study briefly describes the gasification process for heavy residues and com. projects in its application in refinery power generation. The economics of three options, namely, for hydrogen prodn., for power generation, and for coprodn. of hydrogen, power, and syngas, are examd. and compared. All three options provide reasonable payback periods of 3.3, 4.7, and 4.9 yr, resp. However, each refinery must det. its own needs and export potential in its configuration for coprodn. and final implementation of heavy residue gasification.
Applied Catalysis A: General, 2016
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, 1996
The purpose of this paper is to review recent studies on catalytic conversion of benzene in refo... more The purpose of this paper is to review recent studies on catalytic conversion of
benzene in reformate by hydrogenation, hydroisomerization, and alkylation.
Refineries throughout the world are facing challenges in meeting new fuel
specifications; one of them is benzene content in motor gasoline. Almost all the
proposed benzene reduction processes are within the naphtha processing area,
since the reformate is the major source of benzene (typically in the range 2.5-8.0
vol.%), as well as the major component in the gasoline pool. The catalytic
conversion approach discussed in this paper is the most flexible one since it allows
accurate monitoring of the benzene without altering the operation of the reformer
unit. The present paper also briefly compares the costs of various benzene
reduction options and their impact on refinery economics.
Workshop ‘Commercializing Innovations in Petrochemicals’, 2021
An integrated process catalytically cracks whole light crude oil into light olefins , especially ... more An integrated process catalytically cracks whole light crude
oil into light olefins , especially propylene and ethylene . The
process is integrated with an adjacent conventional fluid
catalytic cracking unit whereby the heavy liquid product
mixture ( light and heavy cycle oils ) from whole crude oil
cracking is mixed with vacuum gas oil ( VGO ) for further processing . The process comprises recycling total product
fraction of light cracked naphtha ( LCN ) and mixing with
fresh crude oil feed . High propylene and ethylene yields are
obtained by cracking the whole light crude oil and LCN in
an FCC configuration using a mixture of FCC catalyst and
ZSM - 5 additive at a temperature between , that of conven
tional FCC and steam cracking .