Abstract: An exhaust gas purification catalyst of high resistance which allows highly effective purification of nitric oxide into nontoxic gas, even for an exhaust gas containing oxygen at a high concentration. A carrier of the catalyst includes crystalline pentasil-type aluminosilicate and supports copper and phosphori, the amount of the phosphori being supported ranges from 0.01% to 6.0% by weight as a conversion to P.sub.2 O.sub.5, and ratio of the phosphorus to the copper, i.e., P/Cu (molar ratio) is in 0<(P/Cu).ltoreq.0.7. A method of reducing and eliminating a nitrogen oxide in an exhaust gas in the presence of a hydrocarbon having a ratio of an overall THC concentration/NO.sub.x concentration of 0.5-50 at a reaction temperature of 200.degree.-800.degree. C. in an oxidative atmosphere.

Abstract: A coal combustion apparatus having prevented deterioration of a denitration catalyst due to volatile metal compounds contained in exhaust gases is provided, which apparatus comprises a combustion furnace, a denitration means for removing nitrogen oxides in an exhaust gas from the furnace by reducing nitrogen oxide with ammonia, a means for collecting ashes in the gas having left the denitration means and a means for recycling the collected ashes into the furnace, and is characterized in providing an oxygen concentration meter in the flow path of the gas between the furnace and the denitration means and also providing an oxygen concentration-controlling means relative to air fed inside the flow path of the gas from the furnace to the denitration means so as to control the oxygen concentration detected by the oxygen concentration meter to a definite value or higher.

Abstract: A catalyst for denitration by catalytic reduction using ammonia capable of preventing catalyst deterioation due to vapors of heavy metal compounds contained in exhaust gases and having a high strength and a superior resistance to poisons and a process for producing the catalyst are provided, which catalyst comprises TiO.sub.2, oxide(s) of at least one of V, Cu, Fe and Mn and oxide(s) of at least one of Mo, W and Sn, the total of the mol number(s) of the oxide(s) of at least one of Mo, W and Sn falling within a range of 2.times.10.sup.-6 to 20.times.10.sup.-6 mol/m.sup.2 per the unit specific surface of the catalyst, and which process comprises having oxide(s) of at least one of Mo, W and Sn adsorbed and supported onto a composition comprising TiO.sub.2 prepared in advance and oxide(s) of at least one of V, Fe, Cu and Mn so as to give the above-specified total of the mol number(s) of oxide(s) of at least one of Mo, W and Sn.

Abstract: A catalyst for denitration by catalytic reduction using ammonia capable of preventing catalyst deterioation due to vapors of heavy metal compounds contained in exhaust gases and having a high strength and a superior resistance to poisons and a process for producing the catalyst are provided, which catalyst comprises TiO.sub.2, oxide(s) of at least one of V, Cu, Fe and Mn and oxide(s) of at least one of Mo, W and Sn, the total of the mol number(s) of the oxide(s) of at least one of Mo, W and Sn falling within a range of 2.times.10.sup.-6 to 20.times.10.sup.-6 mol/m.sup.2 per the unit specific surface of the catalyst, and which process comprises having oxide(s) of at least one of Mo, W and Sn absorbed and supported onto a composition comprising TiO.sub.2 prepared in advance and oxide(s) of at least one of V, Fe, Cu and Mn so as to give the above-specified total of the mol number(s) of oxide(s) of at least one of Mo, W and Sn.

Abstract: A catalyst for removing nitrogen oxides contained in exhaust gases, particularly those containing vapor-form catalyst poisons, by catalytic reduction with ammonia, while retaining a high denitration performance for a long time, which catalyst comprises titanium oxide as a first component, molybdenum oxide and/or tungsten oxide as a second component and vanadium oxide and/or sulfate as a third component, the atomic ratio of the respective elements being Ti:Mo and/or W:V=80-96.6:3-15:0.5-5, and the size of the crystallite of the titanium oxide according to Sherrer's equation being in the range of 185 .ANG. to 300 .ANG. in the direction of a plane (101) (interplanar spacing: d=3.52 .ANG.).

Abstract: A catalyst for removing nitrogen oxides whose activity deterioration due to volatile poisons contained in exhaust gases is prevented and which has a superior endurance, and a process for producing the catalyst are provided, which catalyst comprises a titania having a surface area of 20 m.sup.2 /g or less and a zeolite having 0.01 to 20% by weight of copper supported thereon; having an average pore diameter of 10 .ANG. or less; and having a silica/alumina molar ratio of 10 or more, and which process comprises mixing powder of the zeolite with the titania or its precursor, followed by molding the mixture into a predetermined shape, followed by calcining the resulting material at 800.degree. C. or higher.