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.

The process for configuring or reconfiguring a sulfur removal plant having a plurality of Claus units that is greater than the number of downstream tail gas treating units (TGTUs) allows for the regeneration of one of the Claus units without shutting down any of the downstream TGTUs or the other Claus units. Specifically, the regeneration tail gas can be diverted to the reaction furnace of an in-service Claus unit, thereby allowing excess oxygen to be used to regenerate the Claus unit more efficiently, and without exceeding environmental SO2 emission requirements.

The invention describes a filter medium (10), in particular for an air filter, in particular an interior air filter or for a fuel cell, including at least three active layers: a catalytic active layer (12) comprising catalytic activated carbon particles (12a), a second active layer (14) comprising impregnated or catalytic activated carbon particles (14a), a third active layer (16) comprising impregnated or catalytic activated carbon particles (16a), wherein at least one active layer comprises impregnated activated carbon particles and the three active layers (12, 14, 16) differ from one another.

The invention further discloses a filter media body including the filter medium; a filter element including the filter media body or the filter medium; an air filter including the filter element or the filter media body or the filter medium, and a production method for producing the filter medium.

A catalyst for selectively oxidizing hydrogen sulfide to element sulfur, catalyst for burning tail-gas, and process for deeply catalytically oxidizing hydrogen sulfide to sulfur are disclosed. The catalyst for selectively oxidizing hydrogen sulfide to element sulfur is prepared by: 10-34% of iron trioxide and 60-84% of anatase titanium dioxide, and the balance being are auxiliary agents. Also a catalyst for burning tail-gas is prepared by: 48-78% of iron trioxide and 18-48% of anatase titanium dioxide, and the balance being auxiliary agents. The catalyst of the present invention has high selectivity and high sulfur recovery rate. An isothermal reactor and an adiabatic reactor of the present invention are connected in series and are filled with the above two catalysts for reactions, thus reducing total sulfur in the vented gas while having a high sulfur yield and conversion rate.

Catalysts for oxidative sulfur removal and methods of making and using thereof are described herein. The catalysts contain one or more reactive metal salts dispersed on one or more substrates. Suitable reactive metal salts include those salts containing multivariable metals having variable valence or oxidation states and having catalytic activity with sulfur compounds present in gaseous fuel streams. In some embodiments, the catalyst contains one or more compounds that function as an oxygen sponge under the reaction conditions for oxidative sulfur removal. The catalysts can be used to oxidatively remove sulfur-containing compounds from fuel streams, particularly gaseous fuel streams having high sulfur content. Due to the reduced catalyst cost, anticipated long catalyst life and reduced adsorbent consumption, the catalysts described herein are expected to provide a 20-60% reduction in annual desulfurization cost for biogas with sulfur contents ranges from 1000-5000 ppmv compared with the best adsorbent approach.

A preparation method of a titanium-dioxide-based double-layer hollow material includes the following steps: (1) using polystyrene nanospheres with particle size of 180 nm as a template, tetrabutyl titanate as a precursor, to prepare hollow titanium dioxide by calcining; (2) subjecting said hollow titanium dioxide to carboxylation modification to prepare carboxylated titanium dioxide; and (3) dispersing said carboxylated titanium dioxide in ethanol, using chromic nitrate nonahydrate as an assembly agent and trimesic acid as a crosslinking agent to carry out layer-by-layer self-assembly so as to prepare the titanium-dioxide-based double-layer hollow material.

Recovering helium from a gaseous stream includes contacting an acid gas removal membrane with a gaseous stream to yield a permeate stream and a residual stream, removing a majority of the acid gas from the residual stream to yield a first acid gas stream and a helium depleted clean gas stream, removing a majority of the acid gas from the permeate stream to yield a second acid gas stream and a helium rich stream, and removing helium from the helium rich stream to yield a helium product stream and a helium depleted stream. A helium removal system for removing helium from a gaseous stream including hydrocarbon gas, acid gas, and helium includes a first processing zone including a first acid gas removal unit, a second processing zone including a second acid gas removal unit, a third processing zone, and a helium purification unit.

This application is in the field of technologies for desulfurization and demercaptanization of raw gaseous hydrocarbons (including natural gas, tail gas, technological gas, etc, including gaseous media). It can be used for simultaneous dehydration and desulfurization/demercaptanization of any kind of raw gaseous hydrocarbons.

Organic sulfur compounds contained in refinery off gas streams having either high ort low concentrations of olefins are converted to hydrogen sulfides which can be then be removed using conventional amine treating systems. The process uses a catalytic reactor with or without a hydrotreater depending on the olefin concentration of the off gas stream. The catalytic reactor operates in a hydrogenation mode or an oxidation mode to convert a majority of organic sulfur compounds into hydrogen sulfides.

Provided is a renewable wet desulfurization process using a suspension bed, comprising mixing the desulfurization slurry with a hydrogen sulfide containing gas to obtain a first mixture, and passing the first mixture into a suspension bed reactor from bottom to top, with controlling the first mixture to have a dwell time of 5-60 minutes in the suspension bed reactor to allow they contact and react sufficiently with each other; and subjecting a second mixture obtained from the reaction to gas liquid separation to produce a rich solution and a purified gas, subjecting the resulting rich solution to flash evaporation and then reacting with an oxygen-containing gas for carrying out regeneration. The process of the present invention may reduce the hydrogen sulfide content in the hydrogen sulfide containing gas from 2.4-140 g/Nm.sup.3 to 50 ppm or less, so that the desulfurization efficiency is 98% or more. The present invention can achieve regeneration of a spent desulfurizer with a regeneration efficiency as high as 65%-83%, and the barren solution obtained by the regeneration may be recycled for being used as the desulfurization slurry, without generating secondary pollution, which is very suitable for industrial promotion.