Optimal conditions for avoiding emission of polynuclear aromatic hydrocarbons (PAH) during combustion of sherred recycled tire rubber

Abstract

When burning in appropriate furnaces Tire Derived Fuel (TDF), emission of several Polynuclear Aromatic Hydrocarbon (PAH) specimens may occur if optimal conditions are not fulfilled. The exhaust fingerprint pattern ensuing from the equilibrium between pyrosynthesis vs. pyrolysis processes depends on the operating parameters of the furnace chamber. The investigated parameters were: temperature, air shortage, addition of preheated air, exhaust residence time, and presence of cement flour. To scan such conditions, five laboratory combustion simulations were carried out in the range of 400-1000°C. These experiments showed that burning TDF at 800°C is normally optimal for massive PAH production. By contrast, in highly oxidizing conditions above 1000°C and short residence time with no cement flour, only environmentally insignificant amount of PAH (especially those carcinogenic) are generated. Because cement industrial furnaces generally reach temperatures well above 1000°C and may easily fulfill optimal conditions, disposed tires can be conveniently exploited as an economic and environmental friendly alternative fuel. Copyright Enviromedia