Quality and environmental impacts of oil production through pyrolysis of waste tyres

The quality of tyre pyrolysis oil (TPO) and the pollution generated through tyre pyrolysis units were investigated. Two oil types are generally produced, known as light TPO and heavy TPO, exhibiting a pungent smell. Gross calorific value (GCV) of TPO varies from 18275.5 Btu/lb to 18641.8 Btu/lb. GCV shows TPO can be used as fuel oil in industries for energy recovery purposes. The density of heavy oil was lower as compared to light oil. Values of density for both oils were higher than the furnace oil and petroleum, which are 0.96 g/cm³ for local furnace oil and 0.98 g/cm³ for imported furnace oil and 0.88 for petroleum. Results showed that tyre pyrolysis units are badly affecting the surrounding environment. The emission level of CO was 2608 ± 1442.3 mg/Nm³ at site 1, NOx was 826.16 ± 645.52 mg/Nm³ at site 2, SO₂ was 997 ± 1164 at site 2 and emission of PM was 1629 ± 311.6 mg/Nm³ at site 2. The emission level of all these pollutants was above permissible limits. The effluents results show that the concentration of sulphate, TSS, TDS, copper (Cu⁺²), and manganese was above the allowable limit. COD was very high; it varied from 31809 mg/L to 42144 mg/L.