A combustion system operated at low cost is provided. A combustion system 1 includes a combustion device 10 that burns fuel, an exhaust line L1 through which exhaust gas flows, the exhaust gas being generated through combustion of the fuel in the combustion device 10, an air preheater 30 that is disposed in the exhaust line L1 and that recovers heat from the exhaust gas, and a denitration device 40 that is disposed in the exhaust line L1 and that removes nitrogen oxide from the exhaust gas using a denitration catalyst. The denitration device 40 is disposed downstream from the air preheater 30 in the exhaust line L1, and the denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more.

Provided is a catalyst including: a support including titanium oxide; an active catalyst component including vanadium oxide; and a co-catalyst including antimony and cerium, in which the catalyst is included in a deNox reduction reaction that decomposes nitrogen oxide. The catalyst may improve sulfur poisoning tolerance characteristics while improving the deNox efficiency at a temperature in a wide range from low temperature to high temperature.

A exhaust gas mixing apparatus includes an outer cylinder being configured to an insulating ceramic; fins being configured to an insulating ceramic, the fins being provided on an inner side of the outer cylinder; and an electric heating portion embedded in at least a part of the outer cylinder and/or the fins.

An apparatus for treating exhaust gas of a thermal power plant according to the present invention includes: a diffusion module part controlling an exhaust gas flow between a duct disposed at a rear end of a gas turbine of the thermal power plant and the gas turbine to guide the exhaust gas flow toward an inner wall of the duct; a plurality of injection nozzles installed in a flow section in the duct in which the exhaust gas guided toward the inner wall of the duct from the diffusion module part flows, and protruding from the inner wall of the duct; a fluid supply pipe connected to the injection nozzles and extending outside the duct; a fluid supply part supplying a pollutant treatment fluid in liquid phase to the injection nozzles through the fluid supply pipe; and a catalyst module disposed at rear ends of the injection nozzles.

Described is a selective catalytic reduction catalyst comprising a zeolitic framework material of silicon and aluminum atoms, wherein a fraction of the silicon atoms are isomorphously substituted with a tetravalent metal. The catalyst can include a promoter metal such that the catalyst effectively promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H.sub.2O selectively over a temperature range of 150 to 650 C. In another aspect, described is a selective catalytic reduction composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state of IV. The SCR catalyst material promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H.sub.2O selectively over a temperature range of 150 C. to 600 C., and the SCR catalyst material is effective to store ammonia at temperatures of 400 C. and above. A method for selectively reducing nitrogen oxides, and a method for simultaneously selectively reducing nitrogen oxide and storing ammonia are also described. Additionally, an exhaust gas treatment system is also described.

A process for the removal of nitrous oxide (N.sub.2O) contained in a process off-gas in an axial flow reactor. The process includes the steps of (a) adding an amount of reducing agent into the process off-gas; (b) in a first stage passing in axial flow direction the process off-gas admixed with the reducing agent through a first monolithic shaped catalyst active in decomposing nitrous oxide by reaction with the reducing agent to provide a gas with a reduced amount of nitrous oxide and residual amounts of reducing agent; and (c) in a second stage passing the gas with a reduced amount of nitrous oxide and residual amounts of the reducing agent in axial flow direction through a second monolithic shaped catalyst active in oxidation of the residual amounts of the reducing agent.

The present invention relates to a catalyst comprising at least one oxide of vanadium, at least one oxide of tungsten, at least one oxide of cerium, at least one oxide of titanium and at least one oxide of niobium, and an exhaust system containing said oxides.

A process for the cleaning of a lean gas stream contaminated with volatile organic compounds (VOCs) and/or sulfur-containing compounds comprises the steps of adding ozone to the contaminated lean gas stream, subjecting the ozone-containing lean gas stream to ultraviolet irradiation, thereby transforming VOCs to particles, maintaining the irradiated gas stream in a stay zone for a sufficient time to allow aerosol particle growth, and passing the gas stream through a catalytic bag filter at a temperature down to room temperature to remove the formed particles and eliminate any remaining ozone. The bag filter has been made catalytic by impregnation with one or more metal oxides in which the metals are selected from V, W, Pd and Pt, supported on TiO.sub.2.

The present disclosure describes hybrid binary catalysts (HBCs) that can be used as engine aftertreatment catalyst compositions, specifically 4-way catalyst compositions. The HBCs provide solutions to the challenges facing emissions control. In general, the HBCs include a porous primary catalyst and a secondary catalyst. The secondary catalyst partial coats the surfaces (e.g., the internal porous surface and/or the external surface) of the primary catalyst resulting in a hybridized composition. The synthesis of the HBCs can provide a primary catalyst whose entire surface, or portions thereof, can be coated with the secondary catalyst.

The present invention relates to an exhaust gas purification apparatus and an exhaust gas purification method using the same. According to a specific embodiment., the exhaust gas purification apparatus comprises: a diesel oxidation catalyst (DOC) unit for convening nitrogen oxides (NO.sub.8), contained in an exhaust gas introduced therein through a gas inlet portion, into nitrogen dioxide (NO.sub.2); a composite diesel particulate filter (DPF) unit connected to the rear end of the DOC unit through an inflow line and removing harmful components including particulate substances and nitrogen oxides from the exhaust gas discharged from the DOC unit and introduced therein; and a circulation line disposed in the inflow line so as to introduce the exhaust gas discharged from the DOC unit into the gas inlet portion.