ISO 11564 pdf download

ISO 11564 pdf download.Stationary source emissions – Determination of the mass concentration of nitrogen oxides – Naphthylethylenediamine photometric method 1 Scope This International Standard specifies a photometric method for the determination of the mass concentration of nitrogen oxides in exhaust gases from ducts or chimneys. NOTE – Nitrogen oxides (NOx) are practically defined as the sum of NO and NO,. The mass concentration of NOx is expressed as the equivalent NO, concentration in milligrams per cubic metre. The method is applicable to the determination of the mass concentration of nitrogen oxides in exhaust gases from combustion processes, processes for surface treatment of metals and from organic chemical reactions, if necessary after removal by washing, in-furnace reduction and/or catalytic denitration, prior to their dispersion into the atmosphere. This International Standard is applicable to the concentration range 5 mg/m3 to 1 O00 mg/m3 as NO, for a sample gas volume of 1 O00 ml. For gas concentrations greater than 1000 mg/m3, the determination of sample gas concentrations up to 5000 rng/m3 can be performed by diluting the sample solution or by taking an aliquot of the sample solution. This International Standard is not applicable to the determination of dinitrogen monoxide (N,O). 2 Principle Nitrogen oxides in a gas sample are absorbed in an alkaline hydrogen peroxide solution (1,2 mol/l NaOH/ 0,6 % H,OJ in the presence of cupric ions (Cu”), which catalyse the oxidation reaction into nitrite ions. At the above concentrations, nitrate ions are not produced in the absorption solution. Hydrogen peroxide in the absorption solution interferes with the colour development. Therefore, hydrogen peroxide is catalytically decomposed with cupric ions by heating the solution for 30 min in a hot water bath at 80 OC. Nitrite concentration is determined by measuring the absorbance of the coloured solution produced by the reaction with sulfanilamide and naphthylethylenediamine (NEDA) at a wavelength of 545 nm using a photometer. The mass concentration of nitrogen dioxide is obtained by comparison of the absorbance obtained with a calibration graph prepared using a pure sodium nitrite standard solution. The sampling time lies between 5 min and 1 2 min. The time required for the determination is about 60 min. 3 Reagents Use only reagents of recognized analytical grade and distilled water free of nitrite during the analysis. 3.1 Absorption solution (1,2 mol/l NaOH, 0,6 Yo H,O,, 4,O O h Nazco,, 0,0005 o/o HCOONa) Dissolve 48 g of sodium...