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Papers by maryam Khoshtinat Nikoo

Direct conversion of methane to methanol by partial oxidation in a thermal reactor has a poor yie... more Direct conversion of methane to methanol by partial oxidation in a thermal reactor has a poor yield of about 2% which is less than the expected economical yield of about 10%. Conventional thermal catalytic reactors have been proposed to be superseded by plasma reactors as a promising approach, due to strength of the electrical energy which can break C-H bonds of methane. Among the plasma techniques, non-thermal dielectric barrier discharge (DBD) plasma chemical process is one of the most future promising technologies in synthesizing methanol. The purpose of this paper is presenting a brief review of CH4 oxidation with O2 in DBD plasma reactors based on the recent investigations. For this reason, the effect of various parameters of reactor configuration, feed ratio, applied voltage, residence time (gas flow rate), type of applied catalyst, pressure and reactor wall temperature on methane conversion and methanol selectivity are discussed.

Journal of Environmental & Analytical Toxicology, 2016

During her PhD, she spent six months at the University of Sydney to compare the effects of marine... more During her PhD, she spent six months at the University of Sydney to compare the effects of marine pollutants between Mediterranean and Australian sea urchin species. Her research interests lie in ecotoxicology, cellular and molecular biology and development. She has published 4 papers in reputed journals and has been a speaker for more than 10 national and international conferences.

Renewable and Sustainable Energy Reviews, 2017

Global warming, fossil fuel depletion and energy security are driving scientists to investigate t... more Global warming, fossil fuel depletion and energy security are driving scientists to investigate the mechanism of hydrocarbons production from CO 2 hydrogenation. The need for more comprehensive understanding on mechanism of CO 2 hydrogenation to hydrocarbons remains controversial because of the complex reaction mechanism and a large number of involved species. The micromechanism of CO 2 hydrogenation to hydrocarbons has been considered as a possible remedy to fulfill the requirements. This review comprehensively discusses two processes: reverse water gas shift (RWGS) and CO 2 hydrogenation to hydrocarbons. The review includes reaction mechanisms and catalyst effects on yields and rates. In addition, the review outlines each of the Fischer-Tropsch (FT) micromechanisms. The review infers some mechanisms from existing work and proposes a new mechanism that improves several predictions. These mechanisms form the design basis for optimal reactor design.

Methane dry reforming (MDR) is a promising way for fuel production due to the mitigation of carbo... more Methane dry reforming (MDR) is a promising way for fuel production due to the mitigation of carbon dioxide (CO2) and methane (CH4) emissions, as well as tackling global warming. Recently, dielectric barrier discharge (DBD) has received much attention for greenhouse-gas conversion. This study is divided into two main parts. In the first part, the feasibility of the main reactions in MDR as well as the key reactions generating solid carbon was investigated. A carbon-free MDR is practically possible by increasing the temperature higher than 1173 K at the atmospheric pressure, yielding a considerable amount of syngas with hydrogen to carbon monoxide ratio of unity (H2/CO=1) suitable for downstream Fischer–Tropsch synthesis. A thermodynamic analysis was also performed for oxidative MDR to identify the condition for syngas production with no carbon deposition, with the minimum loss of syngas and a higher reactant conversion at a lower temperature. In the second part of the work, extensive...

2 O 3 ; Propylene production One of the important light alkenes as an advantageous intermediate i... more 2 O 3 ; Propylene production One of the important light alkenes as an advantageous intermediate in the manufacture of polyme s and chemicals is propylene. Nowadays, most of propylene is generated as a byproduct o f gaso line production; therefore, the gasoline market demands determine the quantity of pro pylene production. Catalytic dehydrogenatio n of the pro pane is the most selective and conventional route to pro duce this short-chain alkene which has the potential to compensate the sho rtfall o f propylene left by gasoline plants. Industrial dehydrogenation processes use platinum-based catalysts generally supported on alumina and promo ted h Sn. The biggest dehydrogenation unit in Iran has been established in MTBE plant o f BIPC (Bandar Imam Petrochemical Complex) which producing Isobutene from Isobutane by exploiting a commercial catalyst: Pt-Sn-K/Al 2 O 3 (DP-803). In order to feasibility study of propylene pro ductio n rather than Isobutene in this plant, as a prim ary study, some bench-scale reaction tests were perfo rmed on the mentioned catalyst with H 2 /C 3 H 8 as reactants. Fo r the purpose of obtaining the operational conditions, 6 g catalyst were packed in a fixed-bed quartz reactor with the ID o f 10 mm and the length of 62 cm, and then reduced in mixed H 2 /N 2 with a kind of stepwise method. The effects of temperature, WHSV and H 2 /C 3 H 8 ratio were investigated on conversion and yield of propylene. Designing o f the experiments by choosing of one parameter at a time method, 27 runs were accomplished under the reaction temperature range o f 610 to 630 ? C, WHSVs of 2 to 4, H 2 /C 3 H 8 ratio s of 0.6 to 0.8; and atmospheric pressure. Acco rding to data analysis and obtained results, conversion of reactants, yield o f propylene on Pt-Sn-K /Al 2 O 3 (DP-803) attained a maximum value at 34%, when the operational condition were 630 ? C, H 2 /C 3 H 8 = 0.6; and WH SV= 3 hr -1 . γ γ 3

Methanol is currently produced mainly from natural gas by a costly two-step process including syn... more Methanol is currently produced mainly from natural gas by a costly two-step process including syngas conversion to methanol after the production of synthesis gas by steam reforming of methane. This process is not only air-polluted as emits a considerable amount of green-house gases, but also dominant energy-intensive due to stability of methane and its difficult activation for reaction. Utilizing CH 4 along with CO 2 and/or O 2 as reactants in order to methanol production can mitigate global warming issues. Several technologies consisting of catalyst and plasma reactors have been proposed for methanol production because of the strength of the electrical energy which can break the C-H bonds of methane 1,2 . The main defect of the plasma reactors is that they are not as much selective as catalytic processes and lead to unpredictable product distribution. One way to control this difficulty is by using an active and selective catalyst coupled with the plasma reactor. Since gap distance between cathode and anode electrode, residence time of the reactants, feed composition, input power, Temperature, pressure and the type of the applied catalyst are the most effective variables on the hybrid-catalytic dielectric barrier discharge (DBD) plasma reactor efficiency and selectivity to produce methanol 3, 4 , a brief review based on the previous reports for CH 4 oxidation with the presence of CO 2 and/or O 2 are presented. According to the results, the smaller gap distance, relatively higher flow rate of reactants and input power is in favor of methanol production as well as smaller amount of oxygen has a beneficial effect on increasing the methanol yield 3, 5 . Moreover, transient and noble oxide metallic catalysts possessing mild basicity are suggested to be efficient for increasing the methanol yield at even ambient temperature 2, 3 .

A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of... more A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of methane in view of carbon formation was performed with Aspen plus based on direct minimization of Gibbs free energy method. The effects of CO 2 /CH 4 ratio (0.5-3), reaction temperature (573-1473 K) and pressure (1-25 atm) on equilibrium conversions, product compositions and solid carbon were studied. Numerical analysis revealed that the optimal working conditions for syngas production in Fischer-Tropsch synthesis were at temperatures higher than 1173 K for CO 2 /CH 4 ratio being 1 at which about 4 mol of syngas (H 2 /CO = 1) could be produced from 2 mol of reactants with negligible amount of carbon formation. Although temperatures above 973 K had suppressed the carbon formation, the moles of water formed increased especially at higher CO 2 /CH 4 ratios (being 2 and 3). The increment could be attributed to RWGS reaction attested by the enhanced number of CO moles, declined H 2 moles and gradual increment of CO 2 conversion. The simulated reactant conversions and product distribution were compared with experimental results in the literatures to study the differences between the real behavior and thermodynamic equilibrium profile of CO 2 reforming of methane. The potential of producing decent yields of ethylene, ethane, methanol and dimethyl ether seemed to depend on active and selective catalysts. Higher pressures suppressed the effect of temperature on reactant conversion, augmented carbon deposition and decreased CO and H 2 production due to methane decomposition and CO disproportionation reactions. Analysis of oxidative CO 2 reforming of methane with equal amount of CH 4 and CO 2 revealed reactant conversions and syngas yields above 90% corresponded to the optimal operating temperature and feed ratio of 1073 K and CO 2 :CH 4 :O 2 = 1:1:0.1, respectively. The H 2 /CO ratio was maintained at unity while water formation was minimized and solid carbon eliminated.

Fuel Processing Technology, 2011

A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of... more A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of methane in view of carbon formation was performed with Aspen plus based on direct minimization of Gibbs free energy method. The effects of CO 2 /CH 4 ratio (0.5-3), reaction temperature (573-1473 K) and pressure (1-25 atm) on equilibrium conversions, product compositions and solid carbon were studied. Numerical analysis revealed that the optimal working conditions for syngas production in Fischer-Tropsch synthesis were at temperatures higher than 1173 K for CO 2 /CH 4 ratio being 1 at which about 4 mol of syngas (H 2 /CO = 1) could be produced from 2 mol of reactants with negligible amount of carbon formation. Although temperatures above 973 K had suppressed the carbon formation, the moles of water formed increased especially at higher CO 2 /CH 4 ratios (being 2 and 3). The increment could be attributed to RWGS reaction attested by the enhanced number of CO moles, declined H 2 moles and gradual increment of CO 2 conversion. The simulated reactant conversions and product distribution were compared with experimental results in the literatures to study the differences between the real behavior and thermodynamic equilibrium profile of CO 2 reforming of methane. The potential of producing decent yields of ethylene, ethane, methanol and dimethyl ether seemed to depend on active and selective catalysts. Higher pressures suppressed the effect of temperature on reactant conversion, augmented carbon deposition and decreased CO and H 2 production due to methane decomposition and CO disproportionation reactions. Analysis of oxidative CO 2 reforming of methane with equal amount of CH 4 and CO 2 revealed reactant conversions and syngas yields above 90% corresponded to the optimal operating temperature and feed ratio of 1073 K and CO 2 :CH 4 :O 2 = 1:1:0.1, respectively. The H 2 /CO ratio was maintained at unity while water formation was minimized and solid carbon eliminated.

Clean Technologies and Environmental Policy, 2015

Reviews in Chemical Engineering, 2015

The low-temperature Fischer-Tropsch (LTFT) process aims to produce heavy cuts such as wax and die... more The low-temperature Fischer-Tropsch (LTFT) process aims to produce heavy cuts such as wax and diesel. For many years, there have been studies and improvements on the LTFT process to make the existing reactors more efficient. Recent studies have proposed innovative configurations such as monolithic loop and membrane reactors as well as microchannel reactor, which improved the performance of LTFT synthesis. This persuades us to update the existing knowledge about the available reactors. Some fundamental features of the current reactors, which belong to the classes of conventional reactors (fixedbed reactors and slurry reactors) and innovative reactors, are discussed to assist the selection of the most efficient reactors specifically for heavy-cuts production. Published experimental and theoretical works with respect to developments in reactor technology and significant advances in catalysis (such as using structured packing, foams, and knitted wire as catalyst supports due to their excellent radial mixing properties) of the FT process are analyzed and discussed. Consequently, it is shown that the LTFT innovative reactors have higher CO conversions and selectivity of desired heavy cuts. Furthermore, the place of innovative reactors among conventional reactors in terms of effective process parameters on the product distribution has been estimated.

Clean Technologies and Environmental Policy, 2015

Direct conversion of methane to methanol by partial oxidation in a thermal reactor has a poor yie... more Direct conversion of methane to methanol by partial oxidation in a thermal reactor has a poor yield of about 2% which is less than the expected economical yield of about 10%. Conventional thermal catalytic reactors have been proposed to be superseded by plasma reactors as a promising approach, due to strength of the electrical energy which can break C-H bonds of methane. Among the plasma techniques, non-thermal dielectric barrier discharge (DBD) plasma chemical process is one of the most future promising technologies in synthesizing methanol. The purpose of this paper is presenting a brief review of CH4 oxidation with O2 in DBD plasma reactors based on the recent investigations. For this reason, the effect of various parameters of reactor configuration, feed ratio, applied voltage, residence time (gas flow rate), type of applied catalyst, pressure and reactor wall temperature on methane conversion and methanol selectivity are discussed.

Journal of Environmental & Analytical Toxicology, 2016

During her PhD, she spent six months at the University of Sydney to compare the effects of marine... more During her PhD, she spent six months at the University of Sydney to compare the effects of marine pollutants between Mediterranean and Australian sea urchin species. Her research interests lie in ecotoxicology, cellular and molecular biology and development. She has published 4 papers in reputed journals and has been a speaker for more than 10 national and international conferences.

Renewable and Sustainable Energy Reviews, 2017

Global warming, fossil fuel depletion and energy security are driving scientists to investigate t... more Global warming, fossil fuel depletion and energy security are driving scientists to investigate the mechanism of hydrocarbons production from CO 2 hydrogenation. The need for more comprehensive understanding on mechanism of CO 2 hydrogenation to hydrocarbons remains controversial because of the complex reaction mechanism and a large number of involved species. The micromechanism of CO 2 hydrogenation to hydrocarbons has been considered as a possible remedy to fulfill the requirements. This review comprehensively discusses two processes: reverse water gas shift (RWGS) and CO 2 hydrogenation to hydrocarbons. The review includes reaction mechanisms and catalyst effects on yields and rates. In addition, the review outlines each of the Fischer-Tropsch (FT) micromechanisms. The review infers some mechanisms from existing work and proposes a new mechanism that improves several predictions. These mechanisms form the design basis for optimal reactor design.

Methane dry reforming (MDR) is a promising way for fuel production due to the mitigation of carbo... more Methane dry reforming (MDR) is a promising way for fuel production due to the mitigation of carbon dioxide (CO2) and methane (CH4) emissions, as well as tackling global warming. Recently, dielectric barrier discharge (DBD) has received much attention for greenhouse-gas conversion. This study is divided into two main parts. In the first part, the feasibility of the main reactions in MDR as well as the key reactions generating solid carbon was investigated. A carbon-free MDR is practically possible by increasing the temperature higher than 1173 K at the atmospheric pressure, yielding a considerable amount of syngas with hydrogen to carbon monoxide ratio of unity (H2/CO=1) suitable for downstream Fischer–Tropsch synthesis. A thermodynamic analysis was also performed for oxidative MDR to identify the condition for syngas production with no carbon deposition, with the minimum loss of syngas and a higher reactant conversion at a lower temperature. In the second part of the work, extensive...

2 O 3 ; Propylene production One of the important light alkenes as an advantageous intermediate i... more 2 O 3 ; Propylene production One of the important light alkenes as an advantageous intermediate in the manufacture of polyme s and chemicals is propylene. Nowadays, most of propylene is generated as a byproduct o f gaso line production; therefore, the gasoline market demands determine the quantity of pro pylene production. Catalytic dehydrogenatio n of the pro pane is the most selective and conventional route to pro duce this short-chain alkene which has the potential to compensate the sho rtfall o f propylene left by gasoline plants. Industrial dehydrogenation processes use platinum-based catalysts generally supported on alumina and promo ted h Sn. The biggest dehydrogenation unit in Iran has been established in MTBE plant o f BIPC (Bandar Imam Petrochemical Complex) which producing Isobutene from Isobutane by exploiting a commercial catalyst: Pt-Sn-K/Al 2 O 3 (DP-803). In order to feasibility study of propylene pro ductio n rather than Isobutene in this plant, as a prim ary study, some bench-scale reaction tests were perfo rmed on the mentioned catalyst with H 2 /C 3 H 8 as reactants. Fo r the purpose of obtaining the operational conditions, 6 g catalyst were packed in a fixed-bed quartz reactor with the ID o f 10 mm and the length of 62 cm, and then reduced in mixed H 2 /N 2 with a kind of stepwise method. The effects of temperature, WHSV and H 2 /C 3 H 8 ratio were investigated on conversion and yield of propylene. Designing o f the experiments by choosing of one parameter at a time method, 27 runs were accomplished under the reaction temperature range o f 610 to 630 ? C, WHSVs of 2 to 4, H 2 /C 3 H 8 ratio s of 0.6 to 0.8; and atmospheric pressure. Acco rding to data analysis and obtained results, conversion of reactants, yield o f propylene on Pt-Sn-K /Al 2 O 3 (DP-803) attained a maximum value at 34%, when the operational condition were 630 ? C, H 2 /C 3 H 8 = 0.6; and WH SV= 3 hr -1 . γ γ 3

Methanol is currently produced mainly from natural gas by a costly two-step process including syn... more Methanol is currently produced mainly from natural gas by a costly two-step process including syngas conversion to methanol after the production of synthesis gas by steam reforming of methane. This process is not only air-polluted as emits a considerable amount of green-house gases, but also dominant energy-intensive due to stability of methane and its difficult activation for reaction. Utilizing CH 4 along with CO 2 and/or O 2 as reactants in order to methanol production can mitigate global warming issues. Several technologies consisting of catalyst and plasma reactors have been proposed for methanol production because of the strength of the electrical energy which can break the C-H bonds of methane 1,2 . The main defect of the plasma reactors is that they are not as much selective as catalytic processes and lead to unpredictable product distribution. One way to control this difficulty is by using an active and selective catalyst coupled with the plasma reactor. Since gap distance between cathode and anode electrode, residence time of the reactants, feed composition, input power, Temperature, pressure and the type of the applied catalyst are the most effective variables on the hybrid-catalytic dielectric barrier discharge (DBD) plasma reactor efficiency and selectivity to produce methanol 3, 4 , a brief review based on the previous reports for CH 4 oxidation with the presence of CO 2 and/or O 2 are presented. According to the results, the smaller gap distance, relatively higher flow rate of reactants and input power is in favor of methanol production as well as smaller amount of oxygen has a beneficial effect on increasing the methanol yield 3, 5 . Moreover, transient and noble oxide metallic catalysts possessing mild basicity are suggested to be efficient for increasing the methanol yield at even ambient temperature 2, 3 .

A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of... more A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of methane in view of carbon formation was performed with Aspen plus based on direct minimization of Gibbs free energy method. The effects of CO 2 /CH 4 ratio (0.5-3), reaction temperature (573-1473 K) and pressure (1-25 atm) on equilibrium conversions, product compositions and solid carbon were studied. Numerical analysis revealed that the optimal working conditions for syngas production in Fischer-Tropsch synthesis were at temperatures higher than 1173 K for CO 2 /CH 4 ratio being 1 at which about 4 mol of syngas (H 2 /CO = 1) could be produced from 2 mol of reactants with negligible amount of carbon formation. Although temperatures above 973 K had suppressed the carbon formation, the moles of water formed increased especially at higher CO 2 /CH 4 ratios (being 2 and 3). The increment could be attributed to RWGS reaction attested by the enhanced number of CO moles, declined H 2 moles and gradual increment of CO 2 conversion. The simulated reactant conversions and product distribution were compared with experimental results in the literatures to study the differences between the real behavior and thermodynamic equilibrium profile of CO 2 reforming of methane. The potential of producing decent yields of ethylene, ethane, methanol and dimethyl ether seemed to depend on active and selective catalysts. Higher pressures suppressed the effect of temperature on reactant conversion, augmented carbon deposition and decreased CO and H 2 production due to methane decomposition and CO disproportionation reactions. Analysis of oxidative CO 2 reforming of methane with equal amount of CH 4 and CO 2 revealed reactant conversions and syngas yields above 90% corresponded to the optimal operating temperature and feed ratio of 1073 K and CO 2 :CH 4 :O 2 = 1:1:0.1, respectively. The H 2 /CO ratio was maintained at unity while water formation was minimized and solid carbon eliminated.

Fuel Processing Technology, 2011

A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of... more A thermodynamic equilibrium analysis on the multi-reaction system for carbon dioxide reforming of methane in view of carbon formation was performed with Aspen plus based on direct minimization of Gibbs free energy method. The effects of CO 2 /CH 4 ratio (0.5-3), reaction temperature (573-1473 K) and pressure (1-25 atm) on equilibrium conversions, product compositions and solid carbon were studied. Numerical analysis revealed that the optimal working conditions for syngas production in Fischer-Tropsch synthesis were at temperatures higher than 1173 K for CO 2 /CH 4 ratio being 1 at which about 4 mol of syngas (H 2 /CO = 1) could be produced from 2 mol of reactants with negligible amount of carbon formation. Although temperatures above 973 K had suppressed the carbon formation, the moles of water formed increased especially at higher CO 2 /CH 4 ratios (being 2 and 3). The increment could be attributed to RWGS reaction attested by the enhanced number of CO moles, declined H 2 moles and gradual increment of CO 2 conversion. The simulated reactant conversions and product distribution were compared with experimental results in the literatures to study the differences between the real behavior and thermodynamic equilibrium profile of CO 2 reforming of methane. The potential of producing decent yields of ethylene, ethane, methanol and dimethyl ether seemed to depend on active and selective catalysts. Higher pressures suppressed the effect of temperature on reactant conversion, augmented carbon deposition and decreased CO and H 2 production due to methane decomposition and CO disproportionation reactions. Analysis of oxidative CO 2 reforming of methane with equal amount of CH 4 and CO 2 revealed reactant conversions and syngas yields above 90% corresponded to the optimal operating temperature and feed ratio of 1073 K and CO 2 :CH 4 :O 2 = 1:1:0.1, respectively. The H 2 /CO ratio was maintained at unity while water formation was minimized and solid carbon eliminated.

Clean Technologies and Environmental Policy, 2015

Reviews in Chemical Engineering, 2015

The low-temperature Fischer-Tropsch (LTFT) process aims to produce heavy cuts such as wax and die... more The low-temperature Fischer-Tropsch (LTFT) process aims to produce heavy cuts such as wax and diesel. For many years, there have been studies and improvements on the LTFT process to make the existing reactors more efficient. Recent studies have proposed innovative configurations such as monolithic loop and membrane reactors as well as microchannel reactor, which improved the performance of LTFT synthesis. This persuades us to update the existing knowledge about the available reactors. Some fundamental features of the current reactors, which belong to the classes of conventional reactors (fixedbed reactors and slurry reactors) and innovative reactors, are discussed to assist the selection of the most efficient reactors specifically for heavy-cuts production. Published experimental and theoretical works with respect to developments in reactor technology and significant advances in catalysis (such as using structured packing, foams, and knitted wire as catalyst supports due to their excellent radial mixing properties) of the FT process are analyzed and discussed. Consequently, it is shown that the LTFT innovative reactors have higher CO conversions and selectivity of desired heavy cuts. Furthermore, the place of innovative reactors among conventional reactors in terms of effective process parameters on the product distribution has been estimated.

Clean Technologies and Environmental Policy, 2015