Research On The Diffusion Pattern Of Pollutants And Ventilation Design In Industrial Plants

The rubber vulcanization plant generates large amounts of harmful gases during production process,and many sources of gas generation occur due to multiple vulcanization equipment in plants.Most of these emissions are released into the surrounding environment in the form of unorganized exhaust gases.A good indoor environment in plants is essential for ensuring workers’health and improving work efficiency.Based on a vulcanization workshop,this study investigates the influence of displacement ventilation on the distribution of pollutant concentrations in an industrial plant through experimental and numerical research.By combining evaluation indicators,the study analyzes the effects of different ventilation methods and pollutant source characteristics on the velocity distribution and spatiotemporal diffusion of pollutants within the plant.Based on the constructed experimental test rig for multi-pollution sources diffusion,the distribution pattern of pollutants in the chamber was studied by changing position of pollution sources and supplying air velocity.The results showed that when the supply air velocity was 0m/s,the pollution concentration in the center of the multi-source pollution source was higher than that around the pollution source,and the concentration at each test point increases with time.When forced ventilation was adopted,pollutant concentration at each measurement point significantly decreases.With the increase of supplying air velocity from 0m/s to 0.35m/s,the pollutant concentration at the center test point decreases by 78.03%after 420s.Through comparative analysis of the diffusion characteristics of pollutants in industrial plants under different air changes per hour（ACH）,window height（WH）,exhaust outlet layout,and ventilation strategies,it was found that the pollutant concentration in industrial plants,decreases as ACH increases,and the decline rate becomes flat gradually.The ventilation efficiency also decreases with the increase of ACH.Generally,it is suggested that the optimal ACH for industrial plants is set as 20h^-1.When WH increases from 0.5m to 2.5m,the average pollutant concentration in industrial plants rises by 9.70%.By adopting the ventilation mode with exhaust outlet corresponding to the layout,the average pollutant concentration reduces by 35.84%,37.11%,and 37.26%,compared to the other three layout schemes.When the exhaust velocity fluctuates,the pollutant concentration and velocity trend change inversely.With the increase of variable airspeed cycle times,the magnitude of the pollutant concentration has obvious increases.When the wind speed decreases from 1.8m/s to1.2m/s,the pollutant concentration has increased by 58.65%.By comparing pollutants diffusion process in industrial plants under different pollution source temperatures,opening rates and intermittent emission concentrations,it was found that the increase in pollution source temperature was beneficial to the removal of pollutants.When the pollution source temperature increases from 313K to419K,the average concentration of pollutants in the working area decreases from12.292mg/m³ to 4.229 mg/m³,and the purification efficiency rises from 3.400 to 6.932.The overall concentration of pollutants in industrial plants increases linearly with the increase of the pollution source opening rate.When the opening rate of the pollution source increases from 25%to 100%,the concentration of pollutants has increased by312.99%.For the intermittent emission of pollutants,the overall trend of pollutant concentration in the plant increases first and then decreases over time,and the concentration of pollutants under different emission levels reaches the peak at about370s.With the increase of the emission rate of pollutants,the concentration of pollutants in plants increases basically in the same ratio.The diffusion process of pollutants in the industrial plant was comprehensively investigated in this study.The influence of different ventilation flow organization forms and pollution source distribution characteristics on the spatial-temporal distribution characteristics of pollutant concentrations in the plant,were researched and analyzed..The work conducted can deepen researchers’understanding of the diffusion patterns of pollutants in industrial plants under displacement ventilation.Additionally,it provides methods and references for optimizing the design of ventilation systems in industrial plants.