The Boc Group, Inc.

Stephen Rhys Graville

Richard William Watson

Jason Scott Norman

Vijay Ramanand Balse

John Allen Wainford

A feed gas stream containing hydrogen sulfide is subjected to a Claus reaction in a Claus furnace (). Oxygen or oxygen-enriched air containing at least 80% by volume oxygen is supplied to the furnace () to support combustion of the hydrogen sulfide. Sulfur vapour is condensed out of the resultant effluent gas in a sulfur condenser (). The sulfur depleted effluent gas is subjected to a plurality of stages of catalytic reaction of hydrogen sulfide in order to form further sulfur vapour in catalytic reactors () and () with the sulfur vapour being condensed out of the gas in sulfur condensers () and (). The sulfur dioxide content of the resulting tail gas is reduced to hydrogen sulfide in reactor ().

Process for recovering sulphur from a gas stream containing hydrogen sulphide

A method of conducting the partial oxidation to sulphur in at least one furnace of part of the hydrogen sulphide content of a feed gas mixture containing from 10 to 60% by volume of hydrogen sulphide but including at least one aromatic hydrocarbon impurity typically selected from benzene, xylene, toluene and ethyl benzene. A flame is created in the furnace. All the feed gas mixture is fed to the flame. Oxygen molecules are also fed to the flame. At last some of the oxygen molecules are supplied from a source of oxygen-enriched air to pure oxygen, and there is created in the flame at least one hot aromatic hydrocarbon impurity destruction region in which a substantial proportion, typically at least 75% by volume, of the aromatic hydrocarbon impurity is destroyed.

Partial oxidation of hydrogen sulphide

Oxygen or oxygen-enriched air is employed to support combustion in furnaces () and () of part of the hydrogen sulphide content of a first feed gas stream. Sulphur vapour is extracted in condenser () from the resulting gas mixture so as to form a sulphur vapour depleted gas stream. The sulphur vapour depleted gas stream is passed into a catalytic reduction reactor () in which all the residual sulphur dioxide is reduced to hydrogen sulphide. This reduced gas mixture has water vapour extracted therefrom in a quench tower (). The resulting water vapour depleted gas stream flows to a Claus plant for treatment typically together with a second feed gas steam comprising hydrogen sulphide. Employing both furnaces () and () makes it possible to obtain effective conversions to sulphur of the hydrogen sulphide in the feed gas without having the recycle any of the water vapour depleted gas.

Process and apparatus for recovering sulphur from a gas stream containing sulphide

Oxygen or oxygen-enriched air is employed to support combustion in furnace () of part of the hydrogen sulphide content of a first feed gas stream. Sulphur is extracted from the resulting gas stream in a sulphur condenser (). Catalyst Claus reaction between hydrogen sulphide and sulphur dioxide in the resulting sulphur vapour depleted gas stream takes place in a catalytic reactor (). Sulphur is extracted in a further sulphur condenser (). The resulting sulphur vapour depleted gas stream is passed into a catalytic reduction reactor () in which all the residual sulphur dioxide and any sulphur vapour are reduced to hydrogen sulphide. The resulting reduced gas mixture has water vapour extracted there from in a quench tower (). The resulting water vapour depleted gas stream flows to a Claus plant for further treatment typically together with a second feed gas stream.

Process and apparatus for recovering sulphur from a gas stream containing hydrogen sulphide

An air-oxygen hydrogen sulphide burner ( ) fires into a furnace ( ). The burner comprises a main passage for combustion-supporting gas containing air ( ), a multiplicity of spaced apart outer elongate fluid-conducting open ended tubes extending in parallel with each other along the main passage, each of the outlet tubes surrounding at least at the distal end of the burner a respective inner elongate fluid-conducting open ended tube, the inner tubes extending in parallel with one another, a first inlet to the burner for oxygen or oxygen-enriched air, and a second inlet to the burner for feed gas containing hydrogen sulphide, the first inlet communicating with the inner tubs, and the second inlets communicating with the outer tubes.

Sour gas containing hydrogen sulphide has hydrogen sulphide absorbed therefrom in an absorbent in a vessel . A hydrogen sulphide rich gas stream is formed by desorbing hydrogen sulphide from the absorbent in a vessel . The resulting hydrogen sulphide rich gas stream is partially burned in a furnace . Resulting sulphur dioxide reacts therein with residual hydrogen sulphide to form sulphur vapor which is extracted in a condenser . Residual sulphur dioxide and sulphur vapor are reduced to hydrogen sulphide in catalyst stage of a reactor . Water vapor is removed from the resulting reduced gas stream by direct contact with water in a quench tower . At least part of the resulting water vapor depleted gas stream is sent to the vessel with the incoming sour gas stream.

Treatment of a gas stream containing hydrogen sulphide

A process and apparatus for recovering sulphur from a combustible gas stream comprising hydrogen sulphide, air, commercially pure oxygen or oxygen-enriched air. The combustible gas stream are fed to a burner which fires into an elongate furnace. A longitudinally extending flame is created which as a relatively oxygen-poor endothermic hydrogen sulphide dissociation region, and a relatively oxygen-rich, intense hydrogen sulphide combustion region. Residual hydrogen sulphide reacts with sulphur dioxide formed by the combustion to produce sulphur vapor. The furnace has an aspect ratio of about 8:1. The flame diverges from its root to occupy at its maximum cross-sectional area at least about 80% of the cross-sectional area of the furnace interior coplanar therewith.

Treatment of a combustible gas stream

A feed gas stream containing hydrogen sulphide is subjected in a furnace to reactions in which part of the hydrogen sulphide is burned to form sulphur dioxide, and is which the sulphur dioxide reacts with residual hydrogen sulphide to form sulphur vapor. The sulphur vapor is condensed from the gas stream exiting the furnace in a sulphur condenser . Residual sulphur dioxide is reduced back to hydrogen sulphide by hydrogen in a reactor . Water vapor is removed from the reduced gas in a quench tower to form a water vapor-depleted gas stream. One part of the water vapor-depleted gas stream is sent to an adsorber vessel in which hydrogen sulphide is absorbed in an absorbent. The resulting hydrogen sulphide-depleted gas stream is vented from the vessel as a purge stream. Another part of the water vapor-depleted gas stream and a hydrogen sulphide-rich gas formed by desorbing hydrogen sulphide from the absorbent in a vessel are returned as recycle streams to the furnace

Treatment of gas streams containing hydrogen sulphide

Sulphur is recovered from a first gas stream comprising hydrogen sulphide and at least 50% by volume of ammonia and from a second gas stream comprising hydrogen sulphide but essentially no ammonia, the first gas stream, the second gas stream, and combustion supporting gas comprising at least one stream of essentially pure oxygen or oxygen-enriched air are fed to a single combustion zone or a plurality of combustion zones in parallel with each other without premixing of first gas stream or the second gas stream with oxygen or air, and creating in the or each combustion zone at least one region in which thermal cracking of ammonia takes place, and taking from the reactor an effluent gas stream including sulphur vapor, sulphur dioxide, and hydrogen sulphide, but essentially no residual ammonia.

Sulphur recovery

A gas stream containing at least 50% by volume of ammonia but eventually no hydrogen sulphide is burned in a reaction region which is supplied with oxygen and oxygen-enriched air. Both combustion and thermal cracking of ammonia takes place in the reaction region. The rate of supplying oxygen moleculars to the reaction region is from 75 to 98% of the stoichiometric rate required for full combustion of all combustible fluids supplied to the reaction region. Under these conditions essentially no ammonia remains in the effluent gas but formation of oxides of nitrogen can be minimised.

Destruction of waste gas

Sulfur vapor is formed by partial oxidation of hydrogen sulphide. A burner is operated so as to establish a flame in a furnace in or into which the burner fires. There is supplied to the flame from the first region of the mouth of the burner at least one flow of a first combustible gas comprising hydrogen sulfide. At least one second flow of a first oxidizing gas is caused to issue from the mouth of the burner and mix in the flame with the first combustible gas. There is supplied to the flame from a second region of the mouth of the burner surrounding and spaced from the said first region at least one third flow of a second combustible gas comprising hydrogen sulfide. At least one fourth flow of a second oxidizing gas is caused to issue from a region or regions of the mouth of the burner surrounded by said second region and mix in the flame with the second combustible gas. At least one fifth, outermost flow of a third oxidizing gas is caused to mix in the flame with the second combustible gas. A resultant gas mixture including sulfur vapor, water vapor, sulfur dioxide, hydrogen and residual hydrogen sulfide is withdrawn from the furnace.

Partial combustion of hydrogen sulphide

Apparatus for recovering sulphur from a combustible gas stream comprising hydrogen sulphide is provided. The combustible gas stream, air and oxygen, or an oxygen-rich stream, are fed via a coaxial burner into an elongate furnace thereby creating a longitudinally-extending flame which has one or more relatively oxygen-rich, intense, combustion regions wherein hydrogen sulphide is combusted to form sulphur dioxide and one or more relatively oxygen-poor, endothermic, thermal dissociation regions. Residual hydrogen sulphide reacts with sulphur dioxide formed by the combustion to produce sulphur vapor. The apparatus includes a waste heat boiler to reduce the temperature of the furnace effluent and a condenser to remove sulphur therefrom. The furnace has an aspect ratio of about 8:1. The flame diverges from its root to occupy at its maximum cross-sectional area at least about 80% of the cross-sectional area of the furnace interior coplanar therewith.

Apparatus for burning a combustible gas containing hydrogen sulfide

A combustion apparatus includes a moderator gas supply which is added to the fuel to be combusted by concurrent injection to form an intimate admixture as it enters the combustion chamber. Such intimate mixture facilitates a high degree of temperature control within the combustion zone of the flame itself, thereby protecting combustion components and at least reducing or eliminating the formation of thermal NO.sub.x.

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Sheffield, United Kingdom

Stephen Rhys Graville