COSWEET^TM: A New Process to Reach Very High COS Specification on Natural Gas Treatment Combined with Selective H₂S Removal

Abstract

-COSWEET TM , developed for the treatment of COS containing natural gases, is based on a combination of deacidification with any alkanolamine solution and COS hydrolysis on a metal oxide based catalyst. Nearly complete COS conversion is reached, even at a relatively low operating temperature. Coupled with a classical sweetening unit, in which an adapted alkanolamine solvent is used in order to optimise the removal of H 2 S, CO 2 , as well as the H 2 S/CO 2 selectivity, the high catalyst activity and the original integration of the scheme secure the COS removal at minimum extra cost. Benefits on capital and operating expenditures of the plant result both from the reduction of the absorption column and solvent flow rate and from the quality of the acid gas which has positive consequences on the design of the sulfur recovery facilities units, including Claus unit. This paper presents the complete development process approach and the results obtained on COS conversion, the model and simulation tool as well as a case study showing the advantages of coupling COSWEET TM to amine based solvent.Résumé -COSWEET TM : procédé innovant de traitement du gaz naturel combinant une élimination sélective de l'H 2 S et une spécification poussée sur le COS -COSWEET TM , procédé développé pour le traitement du gaz naturel comportant du COS, est une intégration entre un procédé de désacidification à base d'une solution d'alcanolamine et une section catalytique assurant l'hydrolyse du COS à l'aide d'un catalyseur à base d'oxyde métallique. Ce procédé permet d'atteindre des conversions du COS proches de 100 % à basses températures. Lorsque la section catalytique est couplée à une section de désacidification mettant en oeuvre un solvant à base d'une alcanolamine adaptée de telle manière à optimiser l'élimination de l'H 2 S et du CO 2 et également la sélectivité H 2 S/CO 2 , la forte activité du catalyseur et l'intégration originale des deux sections permettent de garantir une spécification sur le COS tout en minimisant les coûts de traitement. Les gains sur les coûts d'investissements et opératoires sont dus non seulement à la réduction de la taille de l'absorbeur et du débit de solvant mais également à la qualité du gaz acide, qui impacte la chaîne soufre en aval, comprenant l'unité Claus.

Prediction of sulfur content in propane and butane after gas purification on a treatment unit

“…In the amine unit, H 2 S and COS are removed from propane using 21% of DEA (Di-Ethanol-Amine) solution as solvent. Amine solvents are very often used for natural gas deacidification purposes as they can be adapted to various specifications and to a wide range of feed gas compositions (Magné-Drisch et al, 2016). Amine section consists of an extractor column for H 2 S removal and a COS removal section with mixersettlers.…”

Understanding the hydrolysis mechanism of cyanogen chloride on copper and chromium surfaces

“…[6][7][8][9][10][11][12][13] In the realm of hydrogen cyanide (HCN) removal technologies, thermodynamically favorable hydrolysis reactions at low temperatures have aroused wide interest. [14,15] However, there is a lack of research on the catalytic hydrolysis reaction of CNCl, which could be pivotal in removing CNCl from specific atmospheres without the need for adsorbent regeneration, thereby providing a less harmful product. The catalytic hydrolysis reaction of CNCl can be represented as follows:…”

“…Several previous density functional theory (DFT) studies have investigated the adsorption strength and behavior of CNCl molecules on various substrates, suggesting the potential of materials such as Al‐ and Ga‐doped BN nanotubes, single‐walled AlN nanotubes, BN nanoclusters, blue phosphorene nanosheets, doped graphene, As‐arm nanoribbons, and red phosphorene nanosheets, as the CNCl toxic gas sensors [6–13] . In the realm of hydrogen cyanide (HCN) removal technologies, thermodynamically favorable hydrolysis reactions at low temperatures have aroused wide interest [14,15] . However, there is a lack of research on the catalytic hydrolysis reaction of CNCl, which could be pivotal in removing CNCl from specific atmospheres without the need for adsorbent regeneration, thereby providing a less harmful product.…”