Claus

The concentrated hydrogen sulfide gas is then sent to the sulfur production unit (Claus process). 

The Claus process converts the H2S to sulfur by controlled combustion of the acid gas and Claus reaction on a catalyst. 

Practically all of the H2S and NH3 is stripped from the water, and, with a small amount of phenols remaining, the gas effluent is sent to the Claus unit. 

Purification of refinery gases by elimination of hydrogen sulfide as well as Claus units for sulfur recovery began to make their appearance. 

In the framework of the new approach third parties have a particular responsibility. Their task has become more difficult especially in cases where products are manufactured directly to the essential requirements. In that case competent interpretation and judgement needs to be applied in order to evaluate whether the required safety level is achieved or not. Not only safeguard clauses and their economic consequences should be avoided but also possible distortion of the market. An exchange of experience between bodies which are notified for a given directive is therefore normally organised with a view to ensuring its coherent application and to avoid such negative consequences. 

Free movement, market surveillance and safeguard clause... 

Where a Member State ascertains tliat a product, bearing the CE-marking and used in accordance with its intended use, is liable to endanger the safety of persons or health, it shall take all appropriate measures to withdraw such a product from the market. That Member State shall immediately Inform the Commission which is obliged to investigate whether or not the measure is justified. Where the Commission considers that the measure is justified, it shall immediately inform the Member State which took the initiative and also the other Member States. This entails that the other Member States must also take action against the product concerned. That latter disposition is referred to as the safeguard clause. 

Tuier circuit (thti tiouse of Santa Claus) a graph can drawn m one path if tlie degree of all the nodes is a 2 3 ... 

In 1875, Mulder (43) extended the synthesis reaction of thiohydantoine to the ethyl ester and amide of chloroacetic acid. Claus (44) demonstrated the acidic properties of thiohydantoin and its ability to form metallic salts. 

The formation of a sulfur-containing ring was justified by the attack of the halogenated carbon of the cMoroacetyl derivative by the sulfur atom of thiourea, a fact in accordance with the results just discussed by Wallach (49,50) and Claus (51). The new formula (37) of thiohydantoine explained why, contrary to thiourea, its desulfuration was difficult. 

These rules are executed in order until a set of rules is satisfied. If all the rules fail then the last default type OS is assigned. The tests on neighboring lines are AND ed together and sets of tests (clauses) separated by blank lines are OR ed. 

R. O. Claus and K. A. Murphy, Proceedings of the Society of Photo-Optical Instrumentation Engineers 2nd International Conference on Optoelectronic Science and Engineering 94, Beijing, Chiaa, Aug. 15—18,1994, 2321, 404—407 (1994). 

The cmde product from the gasifier contains CO2 and H2S, which must be removed before the gas can be used to produce chemicals. The Rectisol process is used to remove these contaminants from the gas. This is accompHshed by scmbbing the product with cold methanol which dissolves the CO2 and H2S and lets the H2 and CO pass through the scmbber. The H2S is sent to a Claus sulfur plant where over 99.7% of the sulfur in the coal feed is recovered in the form of elemental sulfur. A portion of the clean H2 and CO are separated in a cryogenic distillation process. The main product from the cryogenic distillation is a purified CO stream for use in the acetic anhydride process. The remaining CO and hydrogen are used in the methanol plant. 

In 1991, there were approximately 418 sulfur production plants associated with oil and gas production in operation throughout the world. Approximately 86% of these plants were based on the Claus process, and there were 118 Claus units operating in natural gas processing faciHties (11). 

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