Hydrolysis of carbon sulfides on titania and alumina catalysts; the influence of water

Huisman, Henk; Berg, Patrik; Mos, R.; Dillen, A.J. van; Geus, J.W.

doi:10.1016/0926-860x(94)80385-4

Cited by 20 publications

(10 citation statements)

References 6 publications

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“…The activation enthalpy Δ r H m ≠ decreases slowly and monotonously with increasing temperature. We can also see that the activation energy of COS hydrolysis is lower than that of CS 2 hydrolysis, and the rate constant lnk 1 of step 1 is larger than the rate constant lnk 3 of step 3, which shows that CS 2 is more difficult than COS to hydrolyze, in agreement with the results of Huisman [7]. The activation energy of TS1 is the largest and the rate Steps [21] compared to the value of 168.04 kJ mol −1 obtained in our calculation, we reached the same conclusion: that the proton transfer process for the one-water hydrolysis mechanism of carbon disulfide is the rate-determining step.…”

Section: Kinetic Analysis Of Cs 2 Hydrolysissupporting

confidence: 90%

“…Apart from affecting catalysts, the presence of sulfur can also lead to increased corrosion of the reactors used in refining processes [4]. The need to remove CS 2 has become increasingly important, and some technologies-including catalytic hydrolysis, oxidation conversion, and hydrogenation conversion [5][6][7][8][9]-have been developed to remove CS 2 . Attention has recently focused on the hydrolysis of CS 2 due to the mild reaction conditions and relatively few side reactions involved, as well as the fact that it is inexpensive [10].…”

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confidence: 99%

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A theoretical study on the hydrolysis mechanism of carbon disulfide

et al. 2011

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The hydrolysis mechanism of CS(2) was studied using density functional theory. By analyzing the structures of the reactant, transition states, intermediates, and products, it can be concluded that the hydrolysis of CS(2) occurs via two mechanisms, one of which is a two-step mechanism (CS(2) first reacts with an H(2)O, leading to the formation of the intermediate COS, then COS reacts with another H(2)O, resulting in the formation of H(2)S and CO(2)). The other is a one-step mechanism, where CS(2) reacts with two H(2)O molecules continuously, leading to the formation of H(2)S and CO(2). By analyzing the thermodynamics and the change in the kinetic function, it can be concluded that the rate-determining step involves H and OH in H(2)O attacking S and C in CS(2), respectively, causing the C=S double bond to change into a single bond. The two mechanisms are competitive. When performing the hydrolysis of CS(2) with a catalyst, the optimal temperature is below 252°C.

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Section: Kinetic Analysis Of Cs 2 Hydrolysissupporting

confidence: 90%

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confidence: 99%

A theoretical study on the hydrolysis mechanism of carbon disulfide

et al. 2011

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“…Meanwhile, the rate of H 2 S produced by COS hydrolysis is much higher than that of COS produced by CS2 hydrolysis, which indicates that COS generated by CS 2 hydrolysis is the rate-controlling step of the whole series hydrolysis reaction. In addition, the results of Huisman et al [49] show that the order of hydrolysis reaction of CS 2 is closely related to the reaction temperature. When the hydrolysis temperature is lower than 252°C, the hydrolysis reaction of CS 2 is in the negative order for water; when the hydrolysis temperature is between 252-327°C, the hydrolysis reaction of CS 2 is in the positive order for water; when the hydrolysis temperature is higher than 327°C, the hydrolysis reaction of CS 2 is in the zero-order for water, and CS 2 is not affected by temperature.…”

Section: Kinetic Analysis Of Cs 2 Hydrolysismentioning

confidence: 97%

New insights on the theoretical study of hydrolysis mechanism of carbon disulfide (CS2) at low temperature: A density functional theory study

Wang

Zhang

Shi

et al. 2022

Preprint

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Density functional theory (DFT) is used to investigate the two-step hydrolysis mechanism of CS2. By optimizing the structure of reactants, intermediates, transition states, and products, the conclusion shows that the first step of CS2 (CS2 reacts with H2O first to form COS intermediate); The second step (COS intermediate reacts with H2O to form H2S and CO2). Therefore, hydrogen migration is crucial to the mechanism of CS2 hydrolysis. In the first step of the reaction, the rate-determining step in both the single C=S path and the double C=S path has a higher barrier of 199.9 kJ/mol, but the 127.9 kJ/mol barrier in the double C=S path has a lower barrier of 142.8 kJ/mol in the single C=S path. So the double C=S path is better. Similarly, the order of the barriers for the three paths in the second reaction is C=S path < C=S path and C=O path < C=O path. So the C=S path is better. Also, to further explore the reaction of CS2 hydrolysis, the natural bond orbital (NBO) analysis of the transition states was carried out. Besides, to further explain which reaction path is better, the hydrolysis kinetics of CS2 was analyzed. It was found that the hydrolysis of CS2 was an exothermic reaction, and the increase in temperature was unfavorable to the reaction. During the hydrolysis of CS2, the six reaction paths are parallel and competitive. The results will provide a new way to study the catalytic hydrolysis of CS2.

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“…The equilibrium reaction is convoluted by the existence of different species, whose equilibrium concentrations in relation to each other are not exactly known for the total range of process conditions. As stated, other impurities are also produced, which are proven to produce 20-50% of the tail-gas pollutants [13,20]. For instance, Chardonneaua et al [21] showed that 1-3% of toluene as impurity leads to a 50% reduction in conversion efficiency of hydrogen sulfide in the Claus process.…”

Section: Process Descriptionmentioning

confidence: 99%

“…Catalytic pathway for thermally decomposing H 2 S has shown great efficiency, while providing an opportunity to recover the produced hydrogen [10]. Other methods including thermochemical process, photocatalytic approach, electrolysis, hydrolysis and reactive adsorption have also been attempted, showing great potentials for hydrogen recovery and high sulfur recovery rate, but they are all still in their infancy [9,[11][12][13]]. Yet, the Claus process is still the leading pathway for converting hydrogen sulfide to elemental sulfur, owing to its maturity developed over several years of research and operation.…”

Section: Introductionmentioning

confidence: 99%

Investigating efficiency improvement in sulfur recovery unit using process simulation and numerical modeling

Fazlollahi

Asadizadeh

Khoshooei

et al. 2021

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Hydrogen sulfide exists mostly as a detrimental byproduct in the gas processing units as well as refineries, and it must be eliminated from natural gas streams. In a Sulfur Recovery Unit (SRU), hydrogen sulfide is converted into the elemental sulfur during the modified Claus process. Efficiency of sulfur recovery units significantly depends on the reaction furnace temperature. In this work, the effect of oxygen and acid gas enrichment on the reaction furnace temperature and accordingly on sulfur recovery is studied, using both numerical modeling and process simulation. Then, simulation and numerical model are benchmarked against the experimental data of an SRU unit. The validated model provides spotlight on optimizing the upstream sulfur removal unit as well as the oxygen purification process. Two cases of acid gas streams with low and high H2S content, 30% and 50%, are studied to investigate the effect of operating parameters on the overall recovery. Finally, average errors of the models are presented. According to the absolute difference with experimental values, the developed numerical model shows great potential for accurately estimating overall efficiency of the recovery unit.

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Hydrolysis of carbon sulfides on titania and alumina catalysts; the influence of water

Cited by 20 publications

References 6 publications

A theoretical study on the hydrolysis mechanism of carbon disulfide

A theoretical study on the hydrolysis mechanism of carbon disulfide

New insights on the theoretical study of hydrolysis mechanism of carbon disulfide (CS2) at low temperature: A density functional theory study

Investigating efficiency improvement in sulfur recovery unit using process simulation and numerical modeling

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