An energy optimization of production of a thermoplastic material, polyamid-6. i.e. nylon-6, using boiler flue gases heat recovery is presented. Energy and environmental Studies show in increase of process efficiency simultaneously with a decrease of thermal pollution, If the feed water is heated with flue gases, the fuel consumption is reduced by about 13%, while the boiler outlet flue gases temperature decreases from 232degreesC to 55degreesC. Using an air preheater for combustion air preheating. 7.9%, of the fuel will be saved. and at the same time, the atmospheric thermal pollution is diminished because the exhaust flue gases temperature becomes 62degreesC instead of 232degreesC. The combination of feed water and air preheating show's fuel savings of 13.6%, and the outlet flue gases temperature is reduced to 29.7degreesC.