Analysis of Exhaust Gas Dispersion Patterns and Design of High-Efficiency Gas Collection Systems in Semi-Steel Tire Vulcanization Production Lines
To address the issues of high air volume and unorganized emissions of waste gas in semi-steel vulcanization production lines, a combined approach of experimental testing and numerical simulation was employed to study the diffusion characteristics of VOCs-containing waste gas and the air volume of the collection system. The structure of the semi-enclosed hood was optimized, and pipe diameters were adjusted to achieve negative pressure balance, enabling efficient waste gas collection. Results showed that toluene concentration distributions from numerical simulation were largely consistent with experimental measurements, with a maximum average error of -3.9%. Existing hood inlet wind speeds ranged from 0.04 to 0.2 m/s, indicating uneven distribution. Under calm wind conditions, toluene diffusion in enclosed and semi-enclosed hoods was similar, with concentrations of 248 mg/m³ and 115 mg/m³, respectively, and deposition observed in trenches. For a single vulcanizer, at a design air volume of 2700 m³/h, the enclosed hood achieved a toluene concentration of 80 mg/m³ versus 63 mg/m³ for the semi-enclosed hood, demonstrating superior capture of hot fumes. Optimizing the semi-enclosed hood with soft curtains and a height of 1200 mm, at a total design air volume of 1.0×10⁵ m³/h, yielded an average hood inlet velocity of 0.35 m/s but still uneven distribution. Adding 900 mm gradual reducers and adjusting branch pipe diameters resulted in total air volume deviations of -0.44% and 0.38% for branches I and II, respectively, with individual hood deviations below 10%. This achieved negative pressure balance, effective collection, and improved workshop hygiene.