Formation of POM and NOx in connection with the combustion of natural gas in process burners

Measurements of the content of nitrogen oxides and 16 polyaromatic hydrocarbons (PAH), including napthaline, in flue gas from four natural-gas fired process burners with low emission of nitrogen oxides are presented in addition to measurements of the content of oxygen and carbon dioxide. PAH2 emission was highest at high temperatures and an input effect where the proportion of primary air was low. NOx emission was dependent on the variation of the proportion of primary air, flue gas temperature and input effect. NOX emission was highest where the input effect was low, and lowest where the proportion of primary air was low and input effect and flue gas temperature were high. It was possible to adjust the burners so that NO2 emission was reasonably low without PAH2 emission becoming high. It was concluded that the extent of carbon monoxide emission can be used to indicate that of PAH2. Several gas burners of varying design and combustion principles were evaluated with regard to emission of NOx and PAH. Fiber burners gave low emission except in the case of PAH2 which was the same as for the other burners. Carbon monoxide emission was higher in the case of duct burners, but in this case it did not mean that PAH2 emission was higher. (AB)