Systems and methods for producing nitrates, nitric acid, salts thereof, or a mixture thereof are disclosed. The systems may include a feed conduit configured for receiving a feed stream comprising molecular oxygen and molecular nitrogen; an inlet conduit configured for receiving an inlet stream; a plasma reactor fluidically coupled to the inlet conduit, the plasma reactor fluidically coupled to a reactor-outlet conduit configured for receiving the reactor-outlet stream, the plasma reactor configured to produce oxidized nitrogen species; and an absorber fluidically coupled to the reactor-outlet conduit, the absorber configured to receive the reactor outlet stream and to produce nitrates, nitrites, nitric acid, salts thereof, or a mixture thereof from the reactor outlet stream. A recycle conduit may be fluidically coupled to the absorber and the inlet conduit, wherein the recycle conduit is configured to receive the gas-phase stream from the absorber and provide the gas-phase stream to the inlet conduit.

A gas turbine denitrifies combustion gas by using a denitrification catalyst and ammonia as a reducing agent, the gas turbine includes: a turbine provided with turbine blades, the turbine blades being exposed to the combustion gas reaching a temperature higher than an average value in a temperature distribution of the combustion gas, and a compressor configured to supply the turbine blades with a cooling air and the ammonia, wherein the gas turbine is configured to lower the temperature of the turbine blades by supplying the turbine blades with the ammonia and the cooling air.

An exhaust gas dust removal system, comprising a dust removal system inlet, a dust removal system outlet and an electric field apparatus, the electric field apparatus comprising an electric field apparatus inlet, an electric field apparatus outlet, a dust removal electric field cathode and a dust removal electric field anode, the dust removal electric field cathode and the dust removal electric field anode being used for producing an ionising dust removal electric field. A dust collection area of the dust removal electric field anode is larger than a discharge area of the dust removal electric field cathode, so that an asymmetric electrode attraction force is produced between the electrodes, to reduce electric field couplings.

An exhaust gas ozone purification method, specifically comprising: enabling a mixing reaction between an ozone stream and an exhaust gas stream, and removing nitric acid from mixed reaction products between the ozone stream and the exhaust gas stream by using an electrocoagulation device. The electrocoagulation device comprises: a first electrode (301) electrifying water spray of nitric acid; and a second electrode (302) applying an attraction force to the electrified water spray. The method can realize the purification of exhaust gas.

An exhaust gas ozone purification method, specifically comprising: enabling a mixing reaction between an ozone stream and an exhaust gas stream, and removing nitric acid from mixed reaction products between the ozone stream and the exhaust gas stream by using an electrocoagulation device. The electrocoagulation device comprises: a first electrode (301) electrifying water spray of nitric acid; and a second electrode (302) applying an attraction force to the electrified water spray. The method can realize the purification of exhaust gas.

A wet flue gas desulfurization apparatus includes an absorption tank in which an absorption solution containing an alkaline absorbent is stored; an absorption tower extending upward from the absorption tank; a flue gas inlet duct communicating with a first portion of the absorption tower; a flue gas outlet duct communicating with a second portion of the absorption tower; a spray unit to spray the absorption solution inside the absorption tower; a circulation pump to pump the absorption solution from the absorption tank and to supply the absorption solution to the spray unit; a byproduct discharging unit to discharge a byproduct downward from the absorption tank; and an oxygen supply pipe through which an oxygen-containing gas is supplied to a target point in the absorption tank, the target point being adjustable along a vertical direction or a horizontal direction, enabling adjustment of an internal position to which the gas is supplied.

A plant for producing at least partially desulfurized biogas, comprising a biomass digester and/or post-digester, the digester and/or post-digester comprising: a chamber (1) comprising the biomass (2) and the gas space (3), and a system (6) for injecting an oxidizing gas into the gas space,
wherein the injection system comprises a tubular means (4) comprising a T-shaped portion the vertical bar of which is placed in the axis of symmetry of the chamber and the horizontal bar of which has micro-injectors (5).

A method of reducing selenium contamination in a waste water stream is described herein. The method includes channeling a flue gas stream through an absorber, contacting the flue gas stream with an aqueous alkaline-based slurry, such that any selenium byproduct in the flue gas stream forms a selenium compound within the aqueous alkaline-based slurry, controlling oxidation of the selenium compound in the aqueous alkaline-based slurry, and adding a precipitation agent to the aqueous alkaline-based slurry to cause the selenium compound within the aqueous alkaline-based slurry to precipitate.

Plant for producing at least partially desulfurized biogas, comprising a biomass digester and/or post-digester, the digester and/or post-digester comprising: a chamber comprising the biomass and the gas space, and a means for introducing an oxidizing gas,

characterized in that the portion of the inner wall of the chamber situated at the level of the gas space exhibits expansions and/or hollows.

A plant for producing at least partially desulfurized biogas, comprising a biomass digester and/or post-digester, the digester and/or post-digester comprising: a chamber comprising the biomass and the gas space, and a means for introducing an oxidizing gas,
characterized in that the portion of the inner wall of the chamber situated at the level of the gas space is at least partly porous.