Systems and methods for increasing removal efficiency of at least one filter medium. In some embodiments, at least one oxidizing agent is introduced into the flue gas stream, so as to react SO2 with the at least one oxidizing agent to form sulfur trioxide (SO3), sulfuric acid (H2SO4), or any combination thereof. Some of the embodiments further include introducing ammonia (NH3) and or dry sorbent into the flue gas stream, so as to react at least some of the sulfur trioxide (SO3), at least some of the sulfuric acid (H2SO4), or any combination thereof, with the ammonia (NH3) and form at least one salt.

Methods, apparatus, and compositions for cleaning gas. The use of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. The use of different oxidation potentials may reduce unwanted ammonia slip.

The invention is directed to a process and apparatus for removing hydrogen sulfide from a gas stream comprising biogas. In accordance with the invention the gas stream is contacted with an oxidizing agent present in a vessel, whereby said hydrogen sulfide is oxidized into elemental sulfur and said oxidizing agent is reduced, wherein oxygen containing gas is also fed to said vessel, wherein said oxygen oxidizes at least part of said reduced oxidizing agent.

The invention present provides a method (and suitable apparatus) to convert biomass to ethanol, comprising gasifying the biomass to produce raw syngas; feeding the raw syngas to an acid-gas removal unit to remove at least some CO.sub.2 and produce a conditioned syngas stream; feeding the conditioned syngas stream to a fermentor to biologically convert the syngas to ethanol; capturing a tail gas from an exit of the fermentor, wherein the tail gas comprises at least CO.sub.2 and unconverted CO or H.sub.2; and recycling a first portion of the tail gas to the fermentor and/or a second portion of the tail gas to the acid-gas removal unit. This invention allows for increased syngas conversion to ethanol, improved process efficiency, and better overall biorefinery economics for conversion of biomass to ethanol.

A plasma abatement process for abating effluent containing compounds from a processing chamber is described. A plasma abatement process takes gaseous foreline effluent from a processing chamber, such as a deposition chamber, and reacts the effluent within a plasma chamber placed in the foreline path. The plasma dissociates the compounds within the effluent, converting the effluent into more benign compounds. Abating reagents may assist in the abating of the compounds. The abatement process may be a volatizing or a condensing abatement process. Representative volatilizing abating reagents include, for example, CH.sub.4, H.sub.2O, H.sub.2, NF.sub.3, SF.sub.6, F.sub.2, HCl, HF, Cl.sub.2, and HBr. Representative condensing abating reagents include, for example, H.sub.2, H.sub.2O, O.sub.2, N.sub.2, O.sub.3, CO, CO.sub.2, NH.sub.3, N.sub.2O, CH.sub.4, and combinations thereof.

A sorbent composition such as for the removal of a contaminant species from a fluid stream, a method for manufacturing a sorbent composition and a method for the treatment of a flue gas stream to remove heavy metals such as mercury (Hg) therefrom. The sorbent composition includes a porous carbonaceous sorbent such as powdered activated carbon (PAC) and a solid particulate additive that functions as a flow-aid to enhance the pneumatic conveyance properties of the sorbent composition. The solid particulate additive may be a flake-like material, for example a phyllosilicate mineral or graphite.

Methods, apparatus, and compositions for cleaning gas. The use of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. The use of different oxidation potentials may reduce unwanted ammonia slip.

Methods, apparatus, and compositions for cleaning gas. The use of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. The use of different oxidation potentials may reduce unwanted ammonia slip.

Methods and systems are provided for an exhaust gas treatment device. In one example, the exhaust gas treatment device comprises an electrochemical cell having a first electrode, a second electrode and an electrolyte provided between the first and second electrodes, wherein the electrochemical cell is configured to convert a first pollutant species, such as nitric oxide, within the exhaust gas to a second pollutant species, such as nitrogen dioxide, such that a concentration of the second pollutant species within the exhaust gases leaving the exhaust gas treatment device is increased relative to the exhaust gases entering the exhaust gas treatment device.

A method for disposing of excess sulfur dioxide in a flue gas from thermal oxidation of an acid gas stream including hydrogen sulfide recovered from a rich amine solution of an amine plant servicing at least one well head, includes cooling the flue gas to about 300 to about 650 degrees Fahrenheit, injecting a dry sorbent into the flue gas after the step of cooling the flue gas, reacting the dry sorbent after the step of injection, with the sulfur dioxide of the flue gas for sufficient time for formation of reaction byproduct and treated gas, and separating the reaction byproduct from the treated gas. Examples of the dry sorbent include calcium hydroxide, sodium bicarbonate, and trona, as well as magnesium hydroxide and sodium carbonate, and combinations.