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Ashwani K. Gupta - One of the best experts on this subject based on the ideXlab platform.

  • role of toluene and carbon dioxide on sulfur recovery efficiency in a Claus Process
    Energy Procedia, 2015
    Co-Authors: M Chardonneaua, Ashwani K. Gupta, S Ibrahim, A Alshoaibi
    Abstract:

    Examination of the effect of toluene and carbon dioxide, accompanying acid gases (mainly H2S) in the sulfur recovery Process is very critical to determining optimum operating conditions for enhanced sulfur recovery. Experimental and simulation results presented here with the addition of different amounts of toluene or carbon dioxide/toluene mixtures to the H2S gas stream provided direct quantification on the conversion efficiency. The results showed similar trends between the calculated and experimental data, which revealed a decrease in conversion efficiency with increase in toluene and carbon dioxide/toluene addition to the H2S gas stream. The role of reactor operating temperature was also examined. The toluene addition increased the optimum reactor temperature for enhanced sulfur recovery, whereas presence of CO2 reduced the optimum operating temperature. The presence of toluene and CO2 in the acid gas stream directly affects the sulfur recovery efficiency by altering the optimum temperature of the reactor. These results reveal the importance of temperature and its excursion for enhanced sulfur recovery in a Claus Process. Detailed results and analysis are presented in the paper.

  • role of benzene on thermal stage performance in a Claus Process
    53rd AIAA Aerospace Sciences Meeting, 2015
    Co-Authors: S Ibrahim, Ahmed Al Shoaibi, Ashwani K. Gupta
    Abstract:

    Experimental results are presented on the role of benzene addition to H2S combustion at an equivalence ratio of three with respect to H2S and complete combustion of benzene (i.e. under Claus condition). The results reported here are with addition of 0% and 1% benzene to H2S/O2 flame. The results showed that H2S combustion caused H2S to decompose to a minimum mole fraction, which resulted in the formation of SO2 to a maximum mole fraction and then decomposed due to the formation of elemental sulfur, which is favorable under Claus condition. Combustion of H2S and benzene mixture favored the formation of H2 and increased the amounts of H2S at reactor exit after combustion. Benzene also caused faster decomposition of formed SO2 and formation of CO and COS. It is conjectured that benzene hinders the efficiency of Claus reactors and help increase emissions from sulfur recovery plants. These results provide significant insight on direct impact of benzene on the performance of Claus reactor for sulfur capture from acid gases. The results are also of practical value to designers and operators of sulfur plants and policy makers on emission control.

  • role of toluene and carbon dioxide on sulfur recovery efficiency in Claus Process
    Volume 1: Fuels and Combustion Material Handling Emissions; Steam Generators; Heat Exchangers and Cooling Systems; Turbines Generators and Auxiliaries, 2014
    Co-Authors: S Ibrahim, Ahmed S Alshoaibi, Marie Chardonneau, Ashwani K. Gupta
    Abstract:

    Examination of the effect of toluene and carbon dioxide accompanying acid gases (mainly H2S) in the sulfur recovery Process is very critical to determine the optimum operating temperature for enhanced sulfur recovery. Experimental and simulation were used to quantify the conversion efficiency with the addition of different amounts of toluene and carbon dioxide/toluene mixtures to the H2S gas stream. The results showed similar trends between predictions and experimental data, which revealed a decrease in conversion efficiency with increase in toluene or carbon dioxide/toluene addition to the H2S gas stream in a reactor. Further simulations were carried out to seek for the effect of toluene and CO2 addition to acid gas stream on the more favorable operating temperature of the reactor. The results showed that toluene increases the optimum reactor temperature at which enhanced sulfur recovery occurs, whereas it reduces the optimum operating temperature in the presence of CO2. The presence of toluene and CO2 in the acid gas stream affects the sulfur recovery efficiency by altering the optimum temperature of the reactor. These results reveal the importance of reactor temperature and its excursion on sulfur recovery in a Claus Process. The effect of mean reactor temperature and its role on detailed chemical speciation from within the reactor as well as the role of key species formed in the Process on sulfur recovery are presented.Copyright © 2014 by ASME

  • role of toluene on hydrocarbon formation at thermal stage of Claus Process
    52nd Aerospace Sciences Meeting, 2014
    Co-Authors: S Ibrahim, Ahmed Al Shoaibi, Ashwani K. Gupta
    Abstract:

    Experimental results on hydrocarbon formation during the combustion of hydrogen sulfide and hydrogen sulfide-toluene mixture in H2/O2-N2 flames under Claus conditions (Φ=3) are presented. Toluene is often present in acid gases (mainly H2S and CO2) from crude natural gas wells so that combustion of H2S/C7H8 mixture is of significant importance in Claus Process that is used to recover sulfur and energy from acid gases. Role of toluene is isolated from direct comparison of the results from combustion of 100% H2S gas with that of 99% H2S/1% C7H8 gas mixture. The formation and destruction of hydrocarbons and other gas phase species during combustion of H2S and C7H8 mixture are presented. The results revealed decomposition of H2, H2S and the formation of SO2 during combustion of 100% H2S gas. Mole fractions of SO2 increased to an asymptotic value while simultaneously reducing the rate of formation of elemental sulfur. In contrast, combustion of H2S and toluene mixture reduced the rate of H2 oxidation and increased that of H2S, which is attributed to the additional amounts of H2 formation from toluene decomposition and also from the increased reactor temperature. This favored faster increase in SO2 formation to a peak mole fraction but the formed SO2 decomposed with axial distance along the reactor. The decay of SO2 is attributed to the reactions between SO2 and other sulfur containing radicals or formed hydrocarbons to produce elemental sulfur. Presence of toluene fostered the formation of methane, acetylene and carbon disulfide in the reactor. Rate of acetylene formation was observed to be faster than that of methane. Formation of carbon disulfide and hydrocarbons adversely impact the performance and efficiency of sulfur capture in a Claus Process.

  • hydrocarbon formation with toluene in thermal stage of Claus Process
    2014
    Co-Authors: S Ibrahim, Ahmed S Alshoaibi, Ashwani K. Gupta
    Abstract:

    Experimental results on hydrocarbon formation during the combustion of hydrogen sulfide and hydrogen sulfide-toluene mixture in H2/O2-N2 flames under Claus conditions (Φ=3) are presented. Toluene is often present in acid gases (mainly H2S and CO2) from crude natural gas wells so that combustion of H2S/C7H8 mixture is of significant importance in Claus Process that is used to recover sulfur and energy from acid gases. Role of toluene is isolated from direct comparison of the results from combustion of 100% H2S gas with that of 99% H2S/1% C7H8 gas mixture. The formation and destruction of hydrocarbons and other gas phase species during combustion of H2S and C7H8 mixture are presented. The results revealed decomposition of H2, H2S and the formation of SO2 during combustion of 100% H2S gas. Mole fractions of SO2 increased to an asymptotic value while simultaneously reducing the rate of formation of elemental sulfur. In contrast, combustion of H2S and toluene mixture reduced the rate of H2 oxidation and increased that of H2S, which is attributed to the additional amounts of H2 formation from toluene decomposition and also from the increased reactor temperature. This favored faster increase in SO2 formation to a peak mole fraction but the formed SO2 decomposed with axial distance along the reactor. The decay of SO2 is attributed to the reactions between SO2 and other sulfur containing radicals or formed hydrocarbons to produce elemental sulfur. Presence of toluene fostered the formation of methane, acetylene and carbon disulfide in the reactor. Rate of acetylene formation was observed to be faster than that of methane. Formation of carbon disulfide and hydrocarbons adversely impact the performance and efficiency of sulfur capture in a Claus Process.

Sourab Sinha - One of the best experts on this subject based on the ideXlab platform.

  • reaction mechanism for m xylene oxidation in the Claus Process by sulfur dioxide
    Journal of Physical Chemistry A, 2015
    Co-Authors: Sourab Sinha, Ahmed Al Shoaibi, Suk Ho Chung
    Abstract:

    In the Claus Process, the presence of aromatic contaminants such benzene, toluene, and xylenes (BTX), in the H2S feed stream has a detrimental effect on catalytic reactors, where BTX form soot particles and clog and deactivate the catalysts. Among BTX, xylenes are proven to be most damaging contaminant for catalysts. BTX oxidation in the Claus furnace, before they enter catalyst beds, provides a solution to this problem. A reaction kinetics study on m-xylene oxidation by SO2, an oxidant present in Claus furnace, is presented. The density functional theory is used to study the formation of m-xylene radicals (3-methylbenzyl, 2,6-dimethylphenyl, 2,4-dimethylphenyl, and 3,5-dimethylphenyl) through H-abstraction and their oxidation by SO2. The mechanism begins with SO2 addition on the radicals through an O-atom rather than the S-atom with the release of 180.0–183.1 kJ/mol of reaction energies. This exothermic reaction involves energy barriers in the range 3.9–5.2 kJ/mol for several m-xylene radicals. Thereafte...

  • reaction mechanism for the oxidation of aromatic contaminants present in feed gas to Claus Process
    Energy Procedia, 2015
    Co-Authors: Sourab Sinha
    Abstract:

    Abstract Claus Process, consisting of a furnace and catalytic reactors, is used to recover sulfur from H 2 S found in raw natural gas and gases from refineries. H 2 S is accompanied by contaminants such as benzene, toluene, xylenes (collectively called BTX), other hydrocarbons, NH 3 , CO 2 , N 2 and sulfur compounds. Among these, BTX have attracted several research activities as they form soot and sulfur-hydrocarbons in catalytic units that clog and deactivate the catalysts. This work focusses on BTX oxidation by SO 2 as a potential solution that can be carried out in a BTX destruction unit placed between Claus furnace and catalytic units. To determine the extent of BTX destruction by SO 2 , reaction mechanisms are developed using density function theory. The rates of elementary reactions are evaluated using transition state theory. The pathways leading to the formation of CO and SO are obtained.

  • toluene destruction in the Claus Process by sulfur dioxide a reaction kinetics study
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Sourab Sinha, Ahmed S Alshoaibi, Saeed M. Alhassan, Suk Ho Chung
    Abstract:

    The presence of aromatics such as benzene, toluene, and xylene (BTX) as contaminants in the H2S gas stream entering Claus sulfur recovery units has a detrimental effect on catalytic reactors, where BTX forms soot particles and clogs and deactivates the catalysts. BTX oxidation, before they enter catalyst beds, can solve this problem. A theoretical investigation is presented on toluene oxidation by SO2. Density functional theory is used to study toluene radical (benzyl, o-methylphenyl, m-methylphenyl, and p-methylphenyl)–SO2 interactions. The mechanism begins with SO2 addition on the radical through one of the O atoms rather than the S atom. This exothermic reaction involves energy barriers of 4.8–6.1 kJ/mol for different toluene radicals. Thereafter, O–S bond scission takes place to release SO. The reaction rate constants are evaluated to facilitate Process simulations. Among four toluene radicals, the resonantly stabilized benzyl radical exhibited lowest SO2 addition rate. A remarkable similarity between...

  • Toluene Destruction in the Claus Process by Sulfur Dioxide: A Reaction Kinetics Study
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Sourab Sinha, Ahmed S Alshoaibi, Saeed M. Alhassan, Suk Ho Chung
    Abstract:

    The presence of aromatics such as benzene, toluene, and xylene (BTX) as contaminants in the H2S gas stream entering Claus sulfur recovery units has a detrimental effect on catalytic reactors, where BTX forms soot particles and clogs and deactivates the catalysts. BTX oxidation, before they enter catalyst beds, can solve this problem. A theoretical investigation is presented on toluene oxidation by SO2. Density functional theory is used to study toluene radical (benzyl, o-methylphenyl, m-methylphenyl, and p-methylphenyl)-SO2 interactions. The mechanism begins with SO2 addition on the radical through one of the O atoms rather than the S atom. This exothermic reaction involves energy barriers of 4.8-6.1 kJ/mol for different toluene radicals. Thereafter, O-S bond scission takes place to release SO. The reaction rate constants are evaluated to facilitate Process simulations. Among four toluene radicals, the resonantly stabilized benzyl radical exhibited lowest SO2 addition rate. A remarkable similarity between toluene oxidation by O2 and by SO2 is observed

  • Benzene Destruction in Claus Process by Sulfur Dioxide: A Reaction Kinetics Study
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Sourab Sinha, Ahmed S Alshoaibi, Saeed M. Alhassan, Suk Ho Chung
    Abstract:

    Benzene, toluene and xylene (BTX) are present as contaminants in the H 2S gas stream entering a Claus furnace. The exhaust gases from the furnace enter catalytic units, where BTX form soot particles. These particles clog and deactivate the catalysts. A solution to this problem is BTX oxidation before the gases enter catalyst beds. This work presents a theoretical investigation on benzene oxidation by SO2. Density functional theory is used to develop a detailed mechanism for phenyl radical -SO2 interactions. The mechanism begins with SO2 addition to phenyl radical after overcoming an energy barrier of 6.4 kJ/mol. This addition reaction is highly exothermic, where a reaction energy of 182 kJ/mol is released. The most favorable pathway involves O-S bond breakage, leading to the release of SO. A remarkable similarity between the pathways for phenyl radical oxidation by O2 and its oxidation by SO2 is observed. The reaction rate constants are also evaluated to facilitate Process simulations. © 2014 American Chemical Society

Suk Ho Chung - One of the best experts on this subject based on the ideXlab platform.

  • reaction mechanism for m xylene oxidation in the Claus Process by sulfur dioxide
    Journal of Physical Chemistry A, 2015
    Co-Authors: Sourab Sinha, Ahmed Al Shoaibi, Suk Ho Chung
    Abstract:

    In the Claus Process, the presence of aromatic contaminants such benzene, toluene, and xylenes (BTX), in the H2S feed stream has a detrimental effect on catalytic reactors, where BTX form soot particles and clog and deactivate the catalysts. Among BTX, xylenes are proven to be most damaging contaminant for catalysts. BTX oxidation in the Claus furnace, before they enter catalyst beds, provides a solution to this problem. A reaction kinetics study on m-xylene oxidation by SO2, an oxidant present in Claus furnace, is presented. The density functional theory is used to study the formation of m-xylene radicals (3-methylbenzyl, 2,6-dimethylphenyl, 2,4-dimethylphenyl, and 3,5-dimethylphenyl) through H-abstraction and their oxidation by SO2. The mechanism begins with SO2 addition on the radicals through an O-atom rather than the S-atom with the release of 180.0–183.1 kJ/mol of reaction energies. This exothermic reaction involves energy barriers in the range 3.9–5.2 kJ/mol for several m-xylene radicals. Thereafte...

  • toluene destruction in the Claus Process by sulfur dioxide a reaction kinetics study
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Sourab Sinha, Ahmed S Alshoaibi, Saeed M. Alhassan, Suk Ho Chung
    Abstract:

    The presence of aromatics such as benzene, toluene, and xylene (BTX) as contaminants in the H2S gas stream entering Claus sulfur recovery units has a detrimental effect on catalytic reactors, where BTX forms soot particles and clogs and deactivates the catalysts. BTX oxidation, before they enter catalyst beds, can solve this problem. A theoretical investigation is presented on toluene oxidation by SO2. Density functional theory is used to study toluene radical (benzyl, o-methylphenyl, m-methylphenyl, and p-methylphenyl)–SO2 interactions. The mechanism begins with SO2 addition on the radical through one of the O atoms rather than the S atom. This exothermic reaction involves energy barriers of 4.8–6.1 kJ/mol for different toluene radicals. Thereafter, O–S bond scission takes place to release SO. The reaction rate constants are evaluated to facilitate Process simulations. Among four toluene radicals, the resonantly stabilized benzyl radical exhibited lowest SO2 addition rate. A remarkable similarity between...

  • Toluene Destruction in the Claus Process by Sulfur Dioxide: A Reaction Kinetics Study
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Sourab Sinha, Ahmed S Alshoaibi, Saeed M. Alhassan, Suk Ho Chung
    Abstract:

    The presence of aromatics such as benzene, toluene, and xylene (BTX) as contaminants in the H2S gas stream entering Claus sulfur recovery units has a detrimental effect on catalytic reactors, where BTX forms soot particles and clogs and deactivates the catalysts. BTX oxidation, before they enter catalyst beds, can solve this problem. A theoretical investigation is presented on toluene oxidation by SO2. Density functional theory is used to study toluene radical (benzyl, o-methylphenyl, m-methylphenyl, and p-methylphenyl)-SO2 interactions. The mechanism begins with SO2 addition on the radical through one of the O atoms rather than the S atom. This exothermic reaction involves energy barriers of 4.8-6.1 kJ/mol for different toluene radicals. Thereafter, O-S bond scission takes place to release SO. The reaction rate constants are evaluated to facilitate Process simulations. Among four toluene radicals, the resonantly stabilized benzyl radical exhibited lowest SO2 addition rate. A remarkable similarity between toluene oxidation by O2 and by SO2 is observed

  • Benzene Destruction in Claus Process by Sulfur Dioxide: A Reaction Kinetics Study
    Industrial & Engineering Chemistry Research, 2014
    Co-Authors: Sourab Sinha, Ahmed S Alshoaibi, Saeed M. Alhassan, Suk Ho Chung
    Abstract:

    Benzene, toluene and xylene (BTX) are present as contaminants in the H 2S gas stream entering a Claus furnace. The exhaust gases from the furnace enter catalytic units, where BTX form soot particles. These particles clog and deactivate the catalysts. A solution to this problem is BTX oxidation before the gases enter catalyst beds. This work presents a theoretical investigation on benzene oxidation by SO2. Density functional theory is used to develop a detailed mechanism for phenyl radical -SO2 interactions. The mechanism begins with SO2 addition to phenyl radical after overcoming an energy barrier of 6.4 kJ/mol. This addition reaction is highly exothermic, where a reaction energy of 182 kJ/mol is released. The most favorable pathway involves O-S bond breakage, leading to the release of SO. A remarkable similarity between the pathways for phenyl radical oxidation by O2 and its oxidation by SO2 is observed. The reaction rate constants are also evaluated to facilitate Process simulations. © 2014 American Chemical Society

Mehdi Mehrpooya - One of the best experts on this subject based on the ideXlab platform.

  • energy exergy exergoeconomic and sensitivity analyses of modified Claus Process in a gas refinery sulfur recovery unit
    Journal of Cleaner Production, 2019
    Co-Authors: Meysam Hashemi, Fathollah Pourfayaz, Mehdi Mehrpooya
    Abstract:

    Abstract In this study, the sulfur recovery unit based on the modified Claus Process with the split flow is simulated and the results are validated with South Pars gas refinery data. Since optimum energy consumption is essential for community development, exergoeconomic and sensitivity analyses are conducted to prevent waste production and increase energy efficiency in this unit. Energy and exergy analyses are performed to identify the equipment with low exergy efficiency and calculate their exergy destruction extent. Reaction furnace with 4178.8 kW exergy destruction has the highest rate, and then waste heat boiler and P-7 pump are placed. After the pumps, the heat exchangers have the lowest exergy efficiency so that the acid gas preheater with the value of 60% has the lowest one. All equipment investment and operating and maintenance cost calculations are carried out so that the largest cost is related to the hydrolyzing Claus bed that followed by waste heat boiler and P-7 pump. Then equipment exergoeconomic parameters such as exergoeconomic factor, cost rate of exergy destruction and relative cost difference are obtained. The lowest exergoeconomic factor among the Process equipment is related to reaction furnace and second condenser with the values of 0.26% and 0.86%, respectively. The maximum exergoeconomic factor is 94% which is attributed to compressors. The reaction furnace with 4706.16 ($/h) and waste heat boiler with 4629.89 ($/h) have the highest cost rate of exergy destruction and CMPR-5 compressor with 0.2451 ($/h) has the lowest cost rate. Finally, considering some of the functional and economic parameters in the sensitivity analysis procedure, the influence of changing these variables on exergoeconomic parameters have been investigated.

  • modeling and multi optimization of thermal section of Claus Process based on kinetic model
    Journal of Natural Gas Science and Engineering, 2017
    Co-Authors: H Kazempour, Fathollah Pourfayaz, Mehdi Mehrpooya
    Abstract:

    Abstract The Claus Process consists of two basic stages: thermal and catalytic sections. In this study, modeling by a kinetic model and multi-objective optimization of the thermal section of Claus Process were described. The industrial data of the South Pars Refinery in Asaluyeh, Iran was used to validate this model. In order to investigate the influences of the inlet flow rates of fuel and air, inlet stream temperature, furnace pressure and waste heat boiler (WHB) outlet temperature on the sulfur recovery efficiency, the steam production and the H2S/SO2 ratio, a sensitivity analysis was done by simulator software. Three objects of the sulfur recovery efficiency, the steam production and the H2S/SO2 ratio were optimized by using the software and a multi-optimization approach based on the response surface methodology. The results showed that the decrease of the sulfur recovery efficiency from 0.6129 to 0.6099 leads to the addition of 8.54 Kg mole/h to the medium pressure steam production capacity and more closeness of the H2S/SO2 ratio to number 2 for better performance of the catalytic section. However, the 66% improvement in the H2S/SO2 ratio leads to increase the conversion of H2S in the catalytic section, compensating the decrease of the sulfur recovery efficiency in the thermal section. Moreover, the total fuel consumption was reduced about 0.6843 kg mol/h.

S Ibrahim - One of the best experts on this subject based on the ideXlab platform.

  • role of toluene and carbon dioxide on sulfur recovery efficiency in a Claus Process
    Energy Procedia, 2015
    Co-Authors: M Chardonneaua, Ashwani K. Gupta, S Ibrahim, A Alshoaibi
    Abstract:

    Examination of the effect of toluene and carbon dioxide, accompanying acid gases (mainly H2S) in the sulfur recovery Process is very critical to determining optimum operating conditions for enhanced sulfur recovery. Experimental and simulation results presented here with the addition of different amounts of toluene or carbon dioxide/toluene mixtures to the H2S gas stream provided direct quantification on the conversion efficiency. The results showed similar trends between the calculated and experimental data, which revealed a decrease in conversion efficiency with increase in toluene and carbon dioxide/toluene addition to the H2S gas stream. The role of reactor operating temperature was also examined. The toluene addition increased the optimum reactor temperature for enhanced sulfur recovery, whereas presence of CO2 reduced the optimum operating temperature. The presence of toluene and CO2 in the acid gas stream directly affects the sulfur recovery efficiency by altering the optimum temperature of the reactor. These results reveal the importance of temperature and its excursion for enhanced sulfur recovery in a Claus Process. Detailed results and analysis are presented in the paper.

  • role of benzene on thermal stage performance in a Claus Process
    53rd AIAA Aerospace Sciences Meeting, 2015
    Co-Authors: S Ibrahim, Ahmed Al Shoaibi, Ashwani K. Gupta
    Abstract:

    Experimental results are presented on the role of benzene addition to H2S combustion at an equivalence ratio of three with respect to H2S and complete combustion of benzene (i.e. under Claus condition). The results reported here are with addition of 0% and 1% benzene to H2S/O2 flame. The results showed that H2S combustion caused H2S to decompose to a minimum mole fraction, which resulted in the formation of SO2 to a maximum mole fraction and then decomposed due to the formation of elemental sulfur, which is favorable under Claus condition. Combustion of H2S and benzene mixture favored the formation of H2 and increased the amounts of H2S at reactor exit after combustion. Benzene also caused faster decomposition of formed SO2 and formation of CO and COS. It is conjectured that benzene hinders the efficiency of Claus reactors and help increase emissions from sulfur recovery plants. These results provide significant insight on direct impact of benzene on the performance of Claus reactor for sulfur capture from acid gases. The results are also of practical value to designers and operators of sulfur plants and policy makers on emission control.

  • role of toluene and carbon dioxide on sulfur recovery efficiency in Claus Process
    Volume 1: Fuels and Combustion Material Handling Emissions; Steam Generators; Heat Exchangers and Cooling Systems; Turbines Generators and Auxiliaries, 2014
    Co-Authors: S Ibrahim, Ahmed S Alshoaibi, Marie Chardonneau, Ashwani K. Gupta
    Abstract:

    Examination of the effect of toluene and carbon dioxide accompanying acid gases (mainly H2S) in the sulfur recovery Process is very critical to determine the optimum operating temperature for enhanced sulfur recovery. Experimental and simulation were used to quantify the conversion efficiency with the addition of different amounts of toluene and carbon dioxide/toluene mixtures to the H2S gas stream. The results showed similar trends between predictions and experimental data, which revealed a decrease in conversion efficiency with increase in toluene or carbon dioxide/toluene addition to the H2S gas stream in a reactor. Further simulations were carried out to seek for the effect of toluene and CO2 addition to acid gas stream on the more favorable operating temperature of the reactor. The results showed that toluene increases the optimum reactor temperature at which enhanced sulfur recovery occurs, whereas it reduces the optimum operating temperature in the presence of CO2. The presence of toluene and CO2 in the acid gas stream affects the sulfur recovery efficiency by altering the optimum temperature of the reactor. These results reveal the importance of reactor temperature and its excursion on sulfur recovery in a Claus Process. The effect of mean reactor temperature and its role on detailed chemical speciation from within the reactor as well as the role of key species formed in the Process on sulfur recovery are presented.Copyright © 2014 by ASME

  • role of toluene on hydrocarbon formation at thermal stage of Claus Process
    52nd Aerospace Sciences Meeting, 2014
    Co-Authors: S Ibrahim, Ahmed Al Shoaibi, Ashwani K. Gupta
    Abstract:

    Experimental results on hydrocarbon formation during the combustion of hydrogen sulfide and hydrogen sulfide-toluene mixture in H2/O2-N2 flames under Claus conditions (Φ=3) are presented. Toluene is often present in acid gases (mainly H2S and CO2) from crude natural gas wells so that combustion of H2S/C7H8 mixture is of significant importance in Claus Process that is used to recover sulfur and energy from acid gases. Role of toluene is isolated from direct comparison of the results from combustion of 100% H2S gas with that of 99% H2S/1% C7H8 gas mixture. The formation and destruction of hydrocarbons and other gas phase species during combustion of H2S and C7H8 mixture are presented. The results revealed decomposition of H2, H2S and the formation of SO2 during combustion of 100% H2S gas. Mole fractions of SO2 increased to an asymptotic value while simultaneously reducing the rate of formation of elemental sulfur. In contrast, combustion of H2S and toluene mixture reduced the rate of H2 oxidation and increased that of H2S, which is attributed to the additional amounts of H2 formation from toluene decomposition and also from the increased reactor temperature. This favored faster increase in SO2 formation to a peak mole fraction but the formed SO2 decomposed with axial distance along the reactor. The decay of SO2 is attributed to the reactions between SO2 and other sulfur containing radicals or formed hydrocarbons to produce elemental sulfur. Presence of toluene fostered the formation of methane, acetylene and carbon disulfide in the reactor. Rate of acetylene formation was observed to be faster than that of methane. Formation of carbon disulfide and hydrocarbons adversely impact the performance and efficiency of sulfur capture in a Claus Process.

  • hydrocarbon formation with toluene in thermal stage of Claus Process
    2014
    Co-Authors: S Ibrahim, Ahmed S Alshoaibi, Ashwani K. Gupta
    Abstract:

    Experimental results on hydrocarbon formation during the combustion of hydrogen sulfide and hydrogen sulfide-toluene mixture in H2/O2-N2 flames under Claus conditions (Φ=3) are presented. Toluene is often present in acid gases (mainly H2S and CO2) from crude natural gas wells so that combustion of H2S/C7H8 mixture is of significant importance in Claus Process that is used to recover sulfur and energy from acid gases. Role of toluene is isolated from direct comparison of the results from combustion of 100% H2S gas with that of 99% H2S/1% C7H8 gas mixture. The formation and destruction of hydrocarbons and other gas phase species during combustion of H2S and C7H8 mixture are presented. The results revealed decomposition of H2, H2S and the formation of SO2 during combustion of 100% H2S gas. Mole fractions of SO2 increased to an asymptotic value while simultaneously reducing the rate of formation of elemental sulfur. In contrast, combustion of H2S and toluene mixture reduced the rate of H2 oxidation and increased that of H2S, which is attributed to the additional amounts of H2 formation from toluene decomposition and also from the increased reactor temperature. This favored faster increase in SO2 formation to a peak mole fraction but the formed SO2 decomposed with axial distance along the reactor. The decay of SO2 is attributed to the reactions between SO2 and other sulfur containing radicals or formed hydrocarbons to produce elemental sulfur. Presence of toluene fostered the formation of methane, acetylene and carbon disulfide in the reactor. Rate of acetylene formation was observed to be faster than that of methane. Formation of carbon disulfide and hydrocarbons adversely impact the performance and efficiency of sulfur capture in a Claus Process.