Provided is a method for desulphurizating and denitrating a flue gas in an integrated manner based on low-temperature adsorption. The method includes: decreasing a temperature of the flue gas below a room temperature by using a flue gas cooling system; removing moisture in the flue gas by using a dehumidification system; sending the flue gas to a SO.sub.2 and NO.sub.x adsorbing column system; and simultaneously adsorbing SO.sub.2 and NO.sub.x of the flue gas with a material of activated coke, activated carbon, a molecular sieve or diatom mud in the SO.sub.2 and NO.sub.x adsorbing column system to implement an integration of desulphurization and denitration of the flue gas based on the low-temperature adsorption. With the present method, SO.sub.2 and NO.sub.x of the flue gas can be adsorbed simultaneously in an environment having a temperature below the room temperature.

A system and method for purifying engine exhaust by using ozone; the system for purifying engine exhaust by using ozone comprises a reaction field (202), which is used to mix an ozone stream and an exhaust stream for reaction; the system has an excellent purification effect without needing to add a large amount of urea.

This exhaust gas purifying catalyst is provided with a substrate 10 and a catalyst layer 20 formed on a surface of the substrate 10. The catalyst layer 20 contains zeolite particles 22 that support a metal, and a rare earth element-containing compound 24 that contains a rare earth element. The rare earth element-containing compound 24 is added in such an amount that the molar ratio of the rare earth element relative to Si contained in the zeolite 22 is 0.001 to 0.014 in terms of oxides.

This exhaust gas purifying catalyst is provided with a substrate 10 and a catalyst layer 20 formed on a surface of the substrate 10. The catalyst layer 20 contains zeolite particles 22 that support a metal, and a rare earth element-containing compound 24 that contains a rare earth element. The rare earth element-containing compound 24 is added in such an amount that the molar ratio of the rare earth element relative to Si contained in the zeolite 22 is 0.001 to 0.014 in terms of oxides.

Provided is a method for using selective non-catalytic reduction to reduce nitrogen dioxide in exhaust gas generated during an olefin production process. Nitrogen dioxide generated in a catalyst regeneration step of a continuous PDH process can be efficiently removed by the method of the present disclosure. Ultimately, the generation of visible fumes can be prevented through the removal of nitrogen dioxide.

Provided is a method for using selective non-catalytic reduction to reduce nitrogen dioxide in exhaust gas generated during an olefin production process. Nitrogen dioxide generated in a catalyst regeneration step of a continuous PDH process can be efficiently removed by the method of the present disclosure. Ultimately, the generation of visible fumes can be prevented through the removal of nitrogen dioxide.

Methods related generally to the removal of atmospheric pollutants from the gas phase, are provided. The methods involve contacting a first stream comprising NO and/or NO.sub.2 with a second stream comprising (ClO.sub.2).sup.0 to provide a third stream comprising NO and NO.sub.2 at a molar ratio of about 1:1; and contacting the third stream with a fourth stream comprising an aqueous metal hydroxide (MOH) solution to convert NO and NO.sub.2 to MNO.sub.2.

Methods related generally to the removal of atmospheric pollutants from the gas phase, are provided. The methods involve contacting a first stream comprising NO and/or NO.sub.2 with a second stream comprising (ClO.sub.2).sup.0 to provide a third stream comprising NO and NO.sub.2 at a molar ratio of about 1:1; and contacting the third stream with a fourth stream comprising an aqueous metal hydroxide (MOH) solution to convert NO and NO.sub.2 to MNO.sub.2.

An exhaust gas treatment system, comprising an ozone purification system. The ozone purification system comprises an ozone amount control apparatus (209), used to control an amount of ozone so as to effectively oxidize gas components to be treated in exhaust gas, the ozone amount control apparatus (209) comprising a control unit (2091). By means of the present exhaust gas treatment system, particulate matter can be effectively removed from exhaust gas, and the system features a better exhaust gas purification treatment effect.

An exhaust gas treatment system, comprising an ozone purification system. The ozone purification system comprises an ozone amount control apparatus (209), used to control an amount of ozone so as to effectively oxidize gas components to be treated in exhaust gas, the ozone amount control apparatus (209) comprising a control unit (2091). By means of the present exhaust gas treatment system, particulate matter can be effectively removed from exhaust gas, and the system features a better exhaust gas purification treatment effect.