Break | AIChE


In recent years, the entire globe is concerned about the drastic effects of hazardous environmental air pollution. Due to several uncontrollable sources of outdoor and indoor air hazards, the environmental norms cannot be maintained at their level of the threshold value. Moreover, the effects of environmental air nuisance are imposing a direct threat to the health of several life forms and the balanced ecosystem existing on our mother planet. The overall air pollution mainly includes hazardous gaseous effluents and solid particulate matter (PM10, PM2.5, PM1). The present century is suffering from the continuous exposure of carbonaceous gaseous matter CO2, CO, and its associated dust particulates. Such target pollutants or effluents can be easily found from the outlets of steel industrial belts, coal mines, sponge iron industries, etc. as industrial flue gas effluents. Besides tracking down the sources, causes, and associated problems arising out of the concerned target material, it is also quite essential to control as well as monitor or control the entire effects of air pollution. The present study mainly details the design of a modified self-primed venturi scrubber for almost complete removal of target material like CO2 from flue gas and its associated coal dust matters. Coal dust particulate matter constitutes among the greatest source of dust-laden mass and can accordingly harm the natural environment or lifeforms in various ways. The modification of the conventional venturi scrubber has been done in the fully submerged self-priming mode to operate in a more economical way along with a higher level of removal efficiency. The self-primed venturi scrubber is primarily composed of the conventional section, throat section, and diverging section along with the outer cylinder mounted around the periphery of the venturi section. Experimentation proves that a higher level of mass transfer as well as removal efficiency is achieved at a higher liquid level or height of liquid solution within the cylinder. Moreover, inlet liquid velocity and concentration of gaseous mixture or concentration of dust-laden particulate matter like coal dust are the governing parameters for calculating or tabulating the overall removal efficiency. An additional comparison study was carried out between fully and partially submerged conditions, which resulted in 50% greater removal for the former as compared with the latter. Considering the fine coal dust matters, 99.90% of removal was noted at the highest liquid inlet velocity of 60 m/s, having an inlet dust concentration of 3 g/m3 and liquid height of 1m in the outer
cylinder. In the case of CO2 emission from industrial flue gases, similarly, a self-primed venturi scrubber is used for its removal at greater heights. 97.5% maximum removal is recorded with an inlet gaseous concentration of 1500 ppm, having a liquid inlet velocity of 80 m/s with a liquid height of 1m within the outer cylinder. The results quite clearly depict that the highest removal was achieved at higher liquid height within the fully submerged condition, maximum inlet concentration of inlet effluent from industrial flue gas, and highest inlet liquid throat velocity or flow rate. The experimentation was successfully run with recycled wastewater or household
greywater or industrial makeup water as the scrubbing liquid for maintaining environmental sustainability, zero discharge norms, and the economical prospect of the modified scrubbing device. The air-water molecular level of interaction using the physics of phenomena like atomization, direct interception, gravitation, and centrifugal force of action helps in enhanced removal of target material in an energy-efficient way. As an overall study, the modified scrubbing device is capable of eliminating maximum hazardous carbonaceous gaseous matter and solid particulate matter within a short device residence time using low-cost scrubbing as a water
medium. This innovative user-friendly scrubbing technique mainly helps in maintaining or controlling the atmospheric pollution level at its best and accordingly monitoring the ecological balance between nature as well as mankind.