Methods and systems for producing aromatics and light olefins from a mixed plastics stream are described. The method may include feeding a plastic feedstock to a dechlorination operation to melt the plastic feedstock to release HCl and generate a liquid plastic stream; feeding the liquid plastic stream to a pyrolysis reactor, the pyrolysis reactor to generate hydrocarbon vapors; feeding the hydrocarbon vapors to an acid gas removal reactor with a solid inorganic alkali salt disposed within the reaction vessel to remove residual HCl and sulfur-containing compounds from the hydrocarbon vapors to generate a plastic derived oil; and feeding the plastic derived oil to a steam enhanced catalytic cracking reactor to generate a product stream comprising light olefins having a carbon number of C.sub.2-C.sub.4 and aromatics. The associated system for processing mixed plastics into aromatics and light olefins is also described.

Methods of controlling hydrogen sulfide concentration of a biogas occupying an anaerobic membrane bioreactor (AnMBR) containing a submerged membrane are disclosed herein. Methods of controlling dissolved sulfide concentration of a mixed liquor within the AnMBR are disclosed. The methods include directing wastewater containing sulfur and a chemical oxygen demand (COD) to an AnMBR, withdrawing at least a fraction of the biogas from the AnMBR, directing a pre-determined amount of the withdrawn biogas to a scrubber, directing a remainder of the withdrawn biogas to a gas distributor, and directing the scrubbed biogas to the AnMBR. Systems for treating wastewater having sulfur and COD are disclosed. The systems include an AnMBR, a scouring gas closed loop, a scrubber, and a control mechanism for directing biogas to the scrubber and to a gas distributor. Methods of retrofitting a system for treating wastewater having sulfur and COD are disclosed.

It is an object of the present invention to provide a filter which remove acidic gas in the atmosphere with high efficiency and has excellent water resistance. A filter comprising: an aluminium substrate; and an adsorption layer on a surface of the aluminium substrate, wherein the adsorption layer contains activated carbon, a manganese oxide, and an acrylic resin having a pH of 3.0 to 6.5.

The invention is directed to a continuous process to treat a hydrogen sulphide comprising gas comprising the following steps: (a) contacting the hydrogen sulphide comprising gas with an aqueous alkaline solution further comprising sulphide oxidising bacteria thereby obtaining a loaded aqueous solution comprising sulphide compounds and sulphide oxidising bacteria. (b) contacting the loaded aqueous solution with an oxygen comprising gas to regenerate the sulphide oxidising bacteria to obtain a liquid effluent comprising regenerated sulphide oxidising bacteria which is partly used as the aqueous alkaline solution in step (a). (c) separating elemental sulphur as prepared by the sulphide oxidising bacteria in steps (a) and (b) from the loaded aqueous solution of step (a) and/or from the liquid effluent of step (b) and wherein the consumption of oxygen in step (b) is measured and wherein the supply of oxygen in step (b) is controlled by the measured consumption of oxygen.

Provided herein are methods and systems for treating a tail gas of a Claus process to remove sulfur-containing compounds. The method includes combusting a tail gas of a Claus process in an excess of oxygen gas to yield a thermal oxidizer effluent. The thermal oxidizer effluent includes sulfur dioxide, water vapor, and oxygen. The effluent is routed to a quench tower and contacted with a dilute aqueous acid quench stream to yield sulfurous acid, hydrated sulfur dioxide, or both. The sulfurous acid or hydrated sulfur dioxide is oxidized with the excess oxygen from the thermal oxidizer effluent to yield sulfuric acid.

A method to purify a hydrocarbon gas with hydrogen sulfide as an impurity comprises: (a) charging a chamber with a bed of active-metal carbide of a predetermined mesh-size range; (b) conducting the hydrocarbon gas through the bed of active-metal carbide, forming additional hydrocarbon gas by reaction of the active-metal carbide and the hydrogen sulfide; and (c) filtering from the chamber the hydrocarbon gas without the hydrogen sulfide.

Provided an air cleaning system, which includes: a first reactor which has a first inlet and a first outlet and in which a channel is formed; a first moisture adsorption filter and a first water-soluble gas pollutant adsorption filter that are provided inside the first reactor and are provided so that a gas passes therethrough sequentially while flowing along the channel from the first inlet to the first outlet; a plurality of first magnetrons that are provided at a lateral portion of the first reactor so as to correspond respectively to the first moisture adsorption filter and the first water-soluble gas pollutant adsorption filter and selectively apply microwaves to the first moisture adsorption filter and the first water-soluble gas pollutant adsorption filter; and a heat exchanger that receives hot air containing a water-soluble gas pollutant and moisture, both of which are desorbed from the first moisture adsorption filter and the first water-soluble gas pollutant adsorption filter and are discharged by the first outlet, condenses the moisture into water, and dissolves and discharges the water-soluble gas pollutant in the condensed water. According to the present invention, the air cleaning system can unify a dehumidifying process and a water-soluble gas pollutant removing process to simplify an air cleaning process, recover and recycle waste heat by introducing microwaves and the heat exchanger so as to contribute to energy saving, and be used semi-permanently without a need to periodically replace a filter.

Structured adsorbent beds comprising a high cell density substrate, such as greater than about 1040 cpsi, and a coating comprising adsorbent particles, such as DDR and a binder, such as SiO.sub.2 are provided herein. Methods of preparing the structured adsorbent bed and gas separation processes using the structured adsorbent bed are also provided herein.

A process is disclosed for the removal of hydrogen sulfide (H.sub.2S) from natural. This process provides for passing a natural gas feedstream comprising H.sub.2S though a regenerable adsorbent media which adsorbs H.sub.2S to provide an H.sub.2S-lean natural gas product and H.sub.2S. The regenerable adsorbent media of the present invention is a tertiary amine functionalized cross-linked macroporous polymeric adsorbent media.

An acid-gas capturing apparatus according to an embodiment includes an absorption unit configured to discharge an absorption-unit exhaust gas, and a regeneration unit configured to discharge a regeneration unit exhaust gas. The regeneration unit exhaust gas is compressed in a compression unit. The absorption-unit exhaust gas or the regeneration unit exhaust gas before it is compressed by the compression unit is cleaned in a first cleaning unit by means of a first cleaning liquid. A compression-condensate liquid, which is generated by the compression of the regeneration unit exhaust gas in the compression unit, is mixed into the first cleaning liquid through a first compression-condensate-liquid line whose one end is connected to the compression unit.