Method and system for the removal of nitrogen oxides, from flue gas at low temperatures.

Oxygen is removed from a gas feed such as a landfill gas, a digester gas or an industrial CO.sub.2 off-gas by removing sulfur-containing compounds and siloxanes from the feed gas, heating the feed gas, injecting one or more reactants for oxygen conversion into the heated feed gas, carrying out a selective catalytic oxygen conversion in at least onesuitable reactor and cleaning the resulting oxygen-depleted gas. The reactants to be injected comprise one or more of H.sub.2, CO, ammonia, urea, methanol, ethanol and dimethylether (DME).

A multifunctional microwave plasma and ultraviolet light deodorization treatment unit, which includes: a rapid decomposition device (1), a high frequency plasma electric field (2), a microwave plasma electric field (3), a high intensity ultraviolet radiation field (4), a low temperature plasma electric field (5), a high intensity ozone gas reaction chamber (6), a reaction termination chamber (7) and a clean gas organization chamber (8) sequentially installed inside a horizontal rectangular box which has an elongated body defining a horizontal axis and has a channel cavity therein. The deodorization treatment unit further includes an exhaust gas odor collecting pipe and an odor gas storage cabinet (9) connected to an air pump (10), the air pump (10) is connected to an odor gas inlet of the rapid decomposition device (1), the clean gas organization chamber (8) has one end connected to a clean gas exhaust pipe.

A method for the purification of a raw gas stream by selective catalytic oxidation, in which organic and inorganic sulfur compounds, halogenated and non-halogenated volatile organic compounds are selectively oxidized without substantially oxidizing the lower hydrocarbons and the sulfur containing compounds present in the gas to sulfur trioxide and excess of oxygen is removed by oxidation of lower alcohols, ethers or hydrogen added to the raw gas stream upstream the catalytic oxidation.

Oxygen is removed from a gas feed such as a landfill gas, a digester gas or an industrial CO.sub.2 off-gas by heating the feed gas, optionally removing siloxanes and silanols from the heated feed gas, optionally removing part of the sulfur-containing compounds in the heated feed gas, injecting one or more reactants for oxygen conversion into the heated feed gas, carrying out a selective catalytic conversion of any or all of the volatile organic compounds (VOCs) present in the gas, including sulfur-containing compounds, chlorine-containing compounds and any of the reactants injected, in at least one suitable reactor, and cleaning the resulting oxygen-depleted gas. The reactants to be injected comprise one or more of H.sub.2, CO, ammonia, urea, methanol, ethanol and dimethyl ether (DME).

A compact, lightweight, low power aircraft air filtration and VOC removal unit enables the removal of VOCs from cabin air in a passenger aircraft. A plurality of baffles having air flow-through airflow spaces are spaced apart along a duct. UV LEDs are mounted on the interior sides of the outermost baffles, and on both sides of all interior baffles. A filter module is disposed between pairs of baffles, and spaced from the baffles sufficiently to illuminate the entirety of both sides. Each filter modules comprises a plurality of filters. The filters are selected from a coarse foam, a fine foam, or a fused quartz filament felt. Each filter is loaded with a catalyst including one or more of AEROXIDE P25, other pure titanium dioxide (TiO.sub.2), iron-doped TiO.sub.2, carbon-doped TiO.sub.2, and combinations thereof. The catalysts on the filters, under UV illumination, chemically reduce VOCs in the airflow to non-VOC molecules.

A dip-conduit purification apparatus (102) comprises a purification line comprising a plurality of serially coupled purification conduits (124, 126, 128), each of the plurality of purification conduits (124, 126, 128) having an inlet at a first distal end thereof in fluid communication with an outlet at a second distal end thereof.

Systems and methods use oxygen uncoupling metal oxide material for decomposition of NO.sub.x. A gaseous input stream comprising NO.sub.x is contacted with a metal oxide particle, generating nitrogen (N.sub.2) gas and an oxidized metal oxide particle. After contacting the first gaseous input stream with the metal oxide particle, a first gaseous product stream is collected. The first gaseous product stream includes substantially no NO.sub.x. A second gaseous input stream comprising at least one sweeping gas is also contacted with the oxidized metal oxide particle. After contacting the oxidized metal oxide particle, the sweeping gas includes oxygen (O.sub.2) and a reduced metal oxide particle is generated. Then a second gaseous product stream is collected, where the second gaseous product stream includes oxygen (O.sub.2) gas.

A counter-current cross-flow heat exchanger for heating a first gas and cooling a second gas, includes modules in fluid communication with one another, each module being positioned on a plane, the planes mutually overlapping. Conduits allow entry and exit of the first and second gases into and out of the exchanger. Each module has heat exchange plates, with heating and cooling faces. The plates are orthogonal to the module plane and parallel to define alternating heating and cooling spaces. The first gas crosses each heating space with a direction substantially parallel to the plane of each module and the second gas crosses each cooling space with a direction substantially orthogonal to the plane of each module. The cooling spaces between adjacent modules are in direct fluid communication. The heating spaces between adjacent modules are in fluid communication with one another by conduits/conveyors, creating a serpentine path.

A carbon dioxide recovery apparatus has a separator which separates carbon dioxide from a gas by utilizing adsorption and desorption of carbon dioxide to and from an adsorbent caused by pressure fluctuation, the separator including a pressurizer which pressurizes the gas to a pressure that the adsorbent is capable of adsorbing carbon dioxide, and has a dryer having a hygroscopic agent for drying the gas. A regeneration system supplies the residual gas discharged from the separator to the dryer as a regeneration gas for regenerating the hygroscopic agent in the dryer, and the regeneration gas to be supplied to the dryer is heated by an energy converter by utilizing a pressure of a post-regeneration gas discharged by the regeneration of the hygroscopic agent.