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 the 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 air volume of the system. The structure of the semi-enclosed hood was optimized， and the pipe diameter was adjusted to achieve negative pressure balance in the collection system， thereby enabling efficient waste gas collection. The results showed that the toluene concentration distribution obtained from numerical simulation was largely consistent with the experimental test results. The hood inlet wind speeds at various collection hoods on the existing vulcanization production line ranged from 0.04 m/s to 0.2 m/s， indicating uneven wind speed distribution. Under calm wind condition， the toluene diffusion characteristics inside the enclosed hood and the semi-enclosed hood were similar， with toluene concentrations of 248 mg/m³ in the enclosed hood， and 115 mg/m³ in the semi-enclosed hood， and toluene waste gas deposition was observed in the trench. By optimizing the structure of the semi-enclosed hood， with a designed air volume of 1.0×10⁵ m³/h， the average hood inlet wind speed was 0.35 m/s， but the wind speed distribution at the hood inlets remained uneven. Gradual diameter reduction pipes were added to the branches， and the pipe diameters were adjusted. After optimization， the total air volume deviation for branch Ⅰ was -0.44%， and for branch Ⅱ， it was 0.38%. The air volume deviation at each hood inlet was less than 10%， achieving negative pressure balance in the waste gas collection system， which allows for effective waste gas collection and improves the labor hygiene conditions in the workshop. This study can provide industrial parameter references for effective collection of waste gas in semi-steel vulcanization production lines.