Sumitomo Chemical Company, Limited

Takeshi Katsumata

Yasushi Okamoto

Shujiro Shiga

Takashi Nakata

Tadashi Hikasa

Shiga Shujiro

Atsushi Inmaru

Seiji Takaki

Tadashi Higasa

Eiji Inaba

Tsugio Nishioka

A method for the removal of nitrogen oxides from heavy oil combustion exhaust gases containing nitrogen oxides, sulfur oxides and dusts by a catalytic reduction process using a moving catalyst bed reactor wherein the exhaust gases are catalytically contacted with ammonia at 250.degree. to 450.degree. C., which is characterized in that a sealing gas having a temperature of 200.degree. C. or higher, preferably 280.degree. C. or higher, and a pressure higher than the average pressure at the outlet and inlet of the moving catalyst bed reactor is introduced into the portions of the reactor where the catalyst is taken out therefrom and is again supplied thereto, whereby the decrease of the catalyst activity can be effectively prevented.

Method for catalytically reducing nitrogen oxides using moving catalyst

A method for heat recovery in the processes of the removal of nitrogen oxides from exhaust gases containing sulfur oxides and nitrogen oxides by a catalytic or non-catalytic reduction thereof with ammonia. After passing through the reaction zone for the reduction of nitrogen oxides the down flow gases are subjected to the submitted air in a heat exchanger. The process is characterized in that the molar ratio of ammonia to sulfuric anhydride and the concentration of steam in the gases at the inlet of the heat exchanger is controlled in the range of O&lt;NH.sub.3 /SO.sub.3 &lt;2, preferably O&lt;NH.sub.3 /SO.sub.3 &lt;1.5 and more than 12% by volume, preferably more than 15% by volume, respectively, and thereby the process can continuously proceed without the production of ammonium sulfate and the deposition or adhesion thereof onto the surface of the various devices in the apparatus therefor.

Method for the heat recovery in the processes of the removal of nitrogen

A method for the removal of the dusts from combustion exhaust gases, particularly those of heavy oils, by using a fixed packed bed without a remarkable increase in the pressure loss at the fixed packed bed, which is characterized in that the filler filled in the fixed packed bed is a spherical, cylindrical or annular filler containing pores having a pore diameter which ranges from 100 to 70,000 A and a pore volume of not less than 0.1 cm.sup.3 /g, at least 20% of the pores have a pore diameter of not less than 1,000 A, and the filler having a diameter of 1 to 15mm at a minimum.

Method for the removal of the dusts from combustion exhaust gases

A method for removing nitrogen oxides from combustion exhaust gases obtained after removing sulfur oxides by a wet process, which is characterized in that the gases obtained after removing sulfur oxides from the combustion exhaust gases by a wet process are introduced into a wet electrostatic precipitator to remove most of the impurities such as dusts, fumes and mists, passed through a dummy catalyst layer in the form of a fixed bed or a moving bed to remove the remaining impurities which is set before or after heating the gases to a temperature suitable for the reaction of reducing nitrogen oxides, and passed through a metal oxides catalyst layer in the form of a fixed bed in the presence of ammonia which is used at least in the stoichiometric amount required for reducing nitrogen oxides to nitrogen gas by which the gases containing nitrogen oxides are reduced to harmless gases.

Method for removing nitrogen oxides from combustion exhaust gases

Growing community of inventors

Ichihara, Japan

Takeshi Katsumata