Dynamics of reactions of O( 3 P) atoms with CS, CS 2 and OCS

Hsu, David S.; Shaub, Walter M.; Burks, Terrance; Lin, Ming‐Chang

doi:10.1016/0301-0104(79)80114-7

Cited by 32 publications

(20 citation statements)

References 32 publications

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“…66 Measurements of the product distribution at low temperatures indicate values of k 4 /k tot of 8−10% 67−69 whereas k 5 /k tot appears to be in the range 1−5%. 67,69,70 Data for k 4 /k tot in the 250−500 K range 68 and at 1100 K 71 indicate that the branching fraction decreases slightly with temperature but differences may be within experimental uncertainty. We assume that the branching fraction for CS 2 + O is independent of temperature and combine the overall rate constant from Singleton and Cvetanovic 66 and the product distribution from the low temperature work 67−69 to obtain values for k 3 , k 4 , and k 5 .…”

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

Oxidation of Reduced Sulfur Species: Carbon Disulfide

et al. 2014

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A detailed chemical kinetic model for oxidation of CS 2 has been developed, on the basis of ab initio calculations for key reactions, including CS 2 + O 2 and CS + O 2 , and data from literature. The mechanism has been evaluated against experimental results from static reactors, flow reactors, and shock tubes. The CS 2 + O 2 reaction forms OCS + SO, with the lowest energy path involving crossing from the triplet to the singlet surface. For CS + O 2 , which yields OCS + O, we found a high barrier to reaction, causing this step to be important only at elevated temperatures. The model predicts low temperature ignition delays and explosion limits accurately, whereas at higher temperatures it appears to overpredict both the induction time for CS 2 oxidation and the formation rate of [O] upon ignition. The predictive capability of the model depends on the accuracy of the rate constant for the initiation step CS 2 + O 2 , which is difficult to calculate due to the intersystem crossing, and the branching fraction for CS 2 + O, which is measured only at low temperatures. The governing reaction mechanisms are outlined on the basis of calculations with the kinetic model. ■ INTRODUCTIONOff-gases containing carbon disulfide (CS 2 ) are produced together with other sulfur containing compounds such as H 2 S from a range of industrial processes, including the Claus process 1−3 and production of viscous fibers, 4 and in gasification of coal 5 and biomass. 6 Similar to H 2 S and the oxidation product SO 2 , carbon disulfide is toxic and harmful to the environment. Efficient treatment of the sulfur containing off gases becomes a bottleneck in these processes as strict emission requirements must be met. Hence, knowledge of the CS 2 oxidation mechanism is important. Investigations have shown that CS 2 / O 2 mixtures are able to autoignite at low temperature and low pressure 7−13 under conditions of negligible self-heating. Two explosion limits have been reported in the literature, 7−9 and studies have been carried out to determine the effect upon the limits with a change in surface conditions and addition of inert gases. The induction times range from a few seconds to several minutes. 9,11,14 At higher temperatures, CS 2 oxidation has been investigated in flow reactors, 2,15 shock tubes, 16−18 and laminar premixed flames. 19−23 Much of the high-temperature work has been motivated by interest in the CO laser. CS 2 /O 2 flames form CO with its vibrational population inverted, facilitating production of a CO flame laser.Previous studies of the reaction mechanism of carbon disulfide oxidation have mostly been restricted to fuel-lean, dry conditions. 17,18,20,24,25 No reported chemical kinetic models are found to satisfactory describe experimental data across a wider range of mixture composition, temperature, and pressure as the mechanism is complex and accurate kinetic data have been unavailable for several important reactions. The objective of the present study is to develop a detailed chemical kinetic model for oxidation of...

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Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

Oxidation of Reduced Sulfur Species: Carbon Disulfide

et al. 2014

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“…This is in qualitative agreement with previous work, although our value for klb/k{ is somewhat greater than the best previous estimate of 0.014. 18 The carbon monoxide signals (and therefore our value for klb/kf could potentially include a contribution from the following secondary reaction O + CS -CO + S (3) with rate constant (2.0-2.2) X 10"11 cm3 molecule'1 s'1.26 '27 We have performed kinetic modeling calculations on this system using the acuchem kinetic modeling program28 in order to examine the possible effects of this reaction. Figure 4 shows the model predictions for [CO] yield from reactions lb and 3 as a function of photolysis laser power.…”

Section: Calculation Of Number Densities From the Transient Signals W...mentioning

confidence: 99%

“…Energy transfer from vibrationally excited CS or SO into the OCS vx mode is expected to be inefficient because of the large energy mismatch and the requirement for multiple quantum transitions. V-V energy transfer from CO, however, is nearly resonant in energy and is therefore expected to be efficient: CO(u=l) + OCS(00°0) -CO(u=0) + OCS(10°0) (8) Using the CO vibrational distribution measured by Lin et al 18 we can determine the average number of vibrational excitation quanta produced in CO via (lb). Assuming that all of this energy is transferred into vx excitation in OCS, we calculate a maximum possible excitation of 0.37 vx quanta/OCS via this process.…”

Section: Calculation Of Number Densities From the Transient Signals W...mentioning

confidence: 99%

An infrared laser study of the atomic oxygen (3P) + carbon disulfide reaction

Cooper¹,

Hershberger²

1992

J. Phys. Chem.

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“…Hsu et al . conducted an experimental study on COS and O reactions at a low temperature of 300 K and a residence time of few microseconds using an isotope of oxygen, O 18 .…”

Section: Resultsmentioning

confidence: 99%

A reaction kinetics study and model development to predict the formation and destruction of organosulfur species (carbonyl sulfide and mercaptans) in Claus furnace

Rahman

Raj

2018

Int J of Chemical Kinetics

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Carbonyl sulfide (COS), carbon disulfide (CS 2 ), and mercaptans (e.g., CH 3 SH) are unwanted sulfurous species that are produced in sulfur recovery units (SRUs). They can cause equipment corrosion, reduce catalyst activity, and are pollutants for the environment. This necessitates process optimization to minimize their formation in the SRUs using an accurate kinetic model. In this paper, new reactions of COS and mercaptans are studied using the CBS-QB3 level of theory, and their kinetics are evaluated using transition state theory. Such reactions are added to a detailed SRU reaction mechanism, and the updated mechanism is validated using the data on COS and mercaptans from lab-scale experimental setups and an industrial plant. Compared to the previous models, significant improvements in the predicted concentrations of the important species such as COS, carbon monoxide (CO), and sulfur oxides (SO and SO 2 ) are observed due to the inclusion of the new reactions in the mechanism. The simulation studies in a homogeneous reactor within the temperature range of 800-2000 K revealed that furnace temperatures near 1300 K are required to minimize CO and COS formation, while ensuring the oxidation of methane (CH 4 ), mercaptans, and aromatics. Mercaptan formation mainly took place at low temperatures near 900 K.Claus furnace simulations are conducted using industrial feed and operating conditions to show that the optimized inlet air temperature and fuel gas flow rate can assist in simultaneously reducing the emissions of CO and harmful sulfurous species such as COS, CH 3 SH, and CS 2 from the furnace.

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Dynamics of reactions of O( 3 P) atoms with CS, CS 2 and OCS

Cited by 32 publications

References 32 publications

Oxidation of Reduced Sulfur Species: Carbon Disulfide

Oxidation of Reduced Sulfur Species: Carbon Disulfide

An infrared laser study of the atomic oxygen (3P) + carbon disulfide reaction

A reaction kinetics study and model development to predict the formation and destruction of organosulfur species (carbonyl sulfide and mercaptans) in Claus furnace

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