The designing and assessment of a local exhaust ventilation system coupled with hybrid collectors for air pollution control of an alloy steel company

Air pollution is a risk factor for human health and the environment. Due to the nature of the process and also to employing melting furnaces, the production and emission of some pollutants such as harmful dust is very high in the steel industry. Therefore, considering the importance of the issue, control of dusts of an alloy steel production company has been discussed in the present work. In the present study, the VS-55-03 and VS-55-04 standards of industrial ventilation committee of ACGIH have been applied for the design of ventilation system. Ten high efficiency stairmand model cyclones were designed in parallel in order to remove the particulate emissions. Furthermore, a venturi scrubber was designed to be integrated with the ventilation system for controlling of fine particles passing through cyclones. After the system was designed, made, installed, and operated, the concentration of particulates was measured in the workplace, inside the ducts, as well as at the effluent gas to determine the efficiency of the system. The results showed that the average efficiency of the local exhaust system for the removal of the environmental and inhalable particle was 92.7, and 80.3 respectively. Moreover, the mean removal efficiency of the cyclone and venture scrubber was observed to be 73.8% and 98.6% respectively, while it was 99.63% by the coupled cyclone-scrubber system. According to the results, it seems that the hybrid collectors are appropriate alternatives for filtration systems which include constrictions such as sustainability to high temperatures and filter clogging resulting from greasy substances available on scraps.