A process for the removal of hydrogen sulfide and sulfur recovery from a H.sub.2S-containing gas stream by catalytic direct oxidation and Claus reaction through two or more serially connected catalytic reactors, wherein a specific control of the oxygen supplement is operated. The control and improvement of the process is obtained by complementing, in each major step of the process, the H.sub.2S-containing gas stream by a suitable flow of oxygen, namely before the H.sub.2S-containing gas stream enters the Claus furnace, in the first reactor of the process and in the last reactor of the process. Especially in application in a SubDewPoint sulfur recovery process the H.sub.2S/SO.sub.2 ratio is kept constant also during switch-over of the reactors R1 and R by adding the last auxiliary oxygen containing gas directly upstream the last reactor R so that the H.sub.2S/SO.sub.2 ratio can follow the signal of the ADA within a few seconds.

A method for treating an acid gas stream in a sulfur recovery system is provided, the method including providing a motive fluid to an ejector, providing the acid gas stream to the ejector to obtain a mixture, the mixture comprising the motive fluid and the acid gas stream, providing the mixture to a reaction furnace, providing a combustion gas to the reaction furnace, the combustion gas comprising oxygen, and reacting the contents of the reaction furnace. An apparatus for treating an acid gas stream is also provided.

Disclosed is a process for the concurrent production of hydrogen and sulphur from a H.sub.2S-containing gas stream, with zero emissions. The method comprises the thermal oxidative cracking of H.sub.2S so as to form H.sub.2 and S.sub.2. Preferably, the oxidation is conducted using oxygen-enriched air, preferably pure oxygen. The ratio H.sub.2S/O.sub.2 in the feedstock is higher than 2:1, preferably in the range of 3:1-5:1.

A method for increasing sulfur recovery from an acid gas feed comprising the steps of introducing the acid gas feed and a sulfur dioxide enriched air stream to a Claus process to produce a product gas stream, introducing the product gas stream to a thermal oxidizer to produce a flue gas stream, cooling the flue gas stream to produce a cooled take-off stream, separating the cooled take-off stream into a saturated gas stream, heating the saturated gas stream to produce a membrane gas stream, introducing the membrane gas stream to a membrane sweeping unit, the membrane sweeping unit comprises a membrane, the sulfur dioxide in the membrane gas stream permeates the membrane of the membrane sweeping unit, introducing a sweep air stream, the sweep air stream collects the sulfur dioxide to create the sulfur dioxide enriched air stream.

A system and method for removing sulfur compounds from gas, including discharging tail gas having sulfur compounds from a sulfur recovery unit (SRU) to a non-thermal plasma (NTP) catalytic unit including an NTP reactor, providing oxidant to the NTP reactor and placing the oxidant in an NTP state in the NTP reactor to give an oxidative reactive species formed from the oxidant, converting (oxidizing) the sulfur compounds with the oxidative reactive species and catalyst in the NTP catalytic unit into sulfur oxides (SO.sub.x) to discharge the tail gas as treated having the formed SO.sub.x without the sulfur compounds that were converted. The SO.sub.x is absorbed into water in a quench tower to give the tail gas beneficially having only small amounts (e.g., less than 200 ppmv) of sulfur compounds. SO.sub.x may be degassed from water discharged from the quench tower and sent to the SRU furnace.

A method for recovering sulfur from an acid gas feed is provided. The method comprising the steps of mixing the acid gas feed and an absorption process outlet stream to form a combined Claus feed, introducing the combined Claus feed and a sulfur dioxide enriched air feed to a Claus process to produce a Claus outlet gas stream, introducing the Claus outlet gas stream to a thermal oxidizer, treating the thermal oxidizer outlet stream in a gas treatment unit to produce a dehydrated stream, introducing the dehydrated stream to a membrane sweeping unit to produce a sweep membrane residue stream and a sulfur dioxide enriched air feed, introducing a sweep air stream to a permeate side of the membrane sweeping unit, and introducing the sweep membrane residue stream to a sulfur dioxide absorption process to produce the absorption process outlet stream and a stack feed.

A system includes an outlet flowline from an activated carbon bed, a bypass flowline, a furnace, and a control system. The outlet flowline is configured to flow an acid gas stream out of the activated carbon bed after the activated carbon bed has removed benzene, toluene, and xylene from the acid gas stream. The bypass flowline includes a bypass valve and provides an alternative flow path for the acid gas stream exiting the activated carbon bed. The furnace includes a burner configured to combust at least a portion of the acid gas stream. The control system includes a temperature sensor and a controller. The temperature sensor is configured to measure a furnace temperature. The controller is configured to reduce a percent opening of the bypass valve based on the measured furnace temperature.

A method for heat integration in a sulfur recovery unit, the method comprising the steps of reacting the acid gas stream and the air stream in the reaction furnace to produce a reaction effluent, where the reaction effluent comprises elemental sulfur, reducing the temperature of the reaction effluent in the heating extension to produce an effluent stream, reducing the temperature of the reaction effluent in the waste heat boiler to produce a cooled effluent stream, reducing the temperature of the cooled effluent in the sulfur condenser to produce a liquid sulfur stream and a cooled gases stream, where the liquid sulfur stream comprises the elemental sulfur, and increasing a temperature of the cooled gases stream to produce a hot gases stream, where the heating extension is configured to capture heat from the reaction effluent and release the heat to the cooled gases stream.

A process for the removal of hydrogen sulfide and sulfur recovery from a H.sub.2S-containing gas stream by catalytic direct oxidation and Claus reaction through two or more serially connected catalytic reactors, wherein a specific control of the oxygen supplement is operated. The control and improvement of the process is obtained by complementing, in each major step of the process, the H.sub.2S-containing gas stream by a suitable flow of oxygen, namely before the H.sub.2S-containing gas stream enters the Claus furnace, in the first reactor of the process and in the last reactor of the process. Especially in application in a SubDewPoint sulfur recovery process the H.sub.2S/SO.sub.2 ratio is kept constant also during switch-over of the reactors R1 and R by adding the last auxiliary oxygen containing gas directly upstream the last reactor R so that the H.sub.2S/SO.sub.2 ratio can follow the signal of the ADA within a few seconds.

A method for recovering sulfur from an acid gas feed is provided. The method comprising the steps of mixing the acid gas feed and an absorption process outlet stream to form a combined Claus feed, introducing the combined Claus feed and a sulfur dioxide enriched air feed to a Claus process to produce a Claus outlet gas stream, introducing the Claus outlet gas stream to a thermal oxidizer, treating the thermal oxidizer outlet stream in a gas treatment unit to produce a dehydrated stream, introducing the dehydrated stream to a membrane sweeping unit to produce a sweep membrane residue stream and a sulfur dioxide enriched air feed, introducing a sweep air stream to a permeate side of the membrane sweeping unit, and introducing the sweep membrane residue stream to a sulfur dioxide absorption process to produce the absorption process outlet stream and a stack feed.