Influence of Coke-Battery Age on Emission Levels when Heating with Coke Oven Gas

摘要

In 1998, the influence of coke-battery heating -- in particular, the combustion of coke oven gas in furnace heating -- on the quantity of nitrogen oxides (NO_x formed in the combustion products (smokestack gases) was investigated at the Donetsk coke plant (Rutchenkovsk section) in Ukraine [1]. The NO_x content in the emissions was found to increase with temperature rise in the furnace heating system, with increase in air excess coefficient a, and with decrease in recirculation. Most of the nitrogen oxides are formed in the combustion zone of the coke oven gas with thermochemical reaction between the oxygen and atmospheric nitrogen. The quantity of such oxides depends on the temperature and the quantity of oxygen involved in the reaction. Moreover, the NO_X content in the combustion products may increase considerably on account of nitrogen compounds present in the heating gas and the influx of fresh coke oven gas from the coking chamber into the heating system. This influx basically depends on the age of the battery, i.e., the physical state of the lining, the compliance with temperature stipulations, and so on. The influence of battery age on the quantity of NO_X in the smokestack gases is very important; in determining coke output, a key consideration is the associated atmospheric pollution in coke-producing regions and its impact on the biosphere as a whole. Such information is also required for the development of standards objectively reflecting the permissible NO_x emissions in coke production.