Abstract:

Objective To control the emission of volatile organic compounds (VOCs) from trickle impregnation machines and protect workers, occupational health, the local exhaust ventilation (LEV) system was optimized to provide technical reference for VOC control in industrial settings.

Methods Occupational health field investigations, worksite monitoring, and numerical simulations were conducted to optimize the design of the LEV system and evaluate its control performance.

Results Following the system optimization, the measured capture velocity at the control plane of the LEV system installed for trickle impregnation machines increased from a range of 0.05 to 0.13 m/s to a range of 0.68 to 1.21 m/s. All measured capture velocities exceeded 0.4 m/s after modification, meeting the relevant standard requirements. During operation, the measured VOC concentration in the workshop decreased from (54.51 ± 4.91) mg/m³ to (25.60 ± 2.30) mg/m³, while under non-operating conditions, the measured VOC concentration decreased from (68.58 ± 6.87) mg/m³ to (36.68 ± 3.67) mg/m³. In both cases, VOC concentrations were reduced by more than 40% compared with those before the modification.

Conclusions The optimized LEV system improved airflow organization within the hood, enhanced VOC capture efficiency, and effectively reduced VOC concentrations in the workplace. The proposed approach has practical application potential for controlling VOC pollution in similar processes.