Many industries emit obnoxious odours through their processes and the wastes generated. These odours are not only unpleasant but also contain toxic substances that hinder the sate of well-being of the industrial workers, and the people living in the surroundings. Chemical scrubbers have emerged as an effective solution to all odour problems. They can effectively eliminate a broad range of odour causing compounds, and hence make the environment clean, odour-free and pleasant.
Chemical scrubber is the most common type of odour control system. The scrubber’s basic objective is to provide a contact between chemicals, water and odourous air, so as to allow entrainment or oxidation of the odour causing compounds. The scrubber liquid absorbs the odourous compounds. In the scrubber liquid, the odourous compounds are oxidized or removed in the form of a blowdown stream or an overflow.
The scrubber basically consists of a mist eliminator, a sump, recirculation pump, liquid recirculation system having spray nozzles, packing material and a vessel. The odourous air is pushed into the scrubber with the help of a fan. The air passes the packing bed. A liquid solution is sprayed from nozzles over the packing bed. This liquid solution comes in contact with the air, and it absorbs the air. After passing the packing bed, the liquid solution falls within the sump. In the sump, the solution is either discarded or re-circulated. The, the air exits from the packing bed, and it is passed via the mist eliminator for preventing liquid droplets from leaving the scrubber.
Using a Chemical Scrubber:
If you need to remove ammonia or other nitrogen compounds, consider using a two-stage chemical scrubber system, and place a dilute solution of sulfuric acid in its first stage. Sulfuric acid reacts with ammonia and results in the formation of ammonium sulfate. Ammonium sulfate is a non-volatile and soluble salt, which is eliminated from the effluent of the scrubber through overflow.
These scrubbers have proved that they can eliminate about 99.5% of ammonia and hydrogen, even when they are at high concentrations. The footprint required by these systems is relatively small, but they call for significant attention when it comes to storage and chemical handling, and their maintenance and operation. The disposal of wastewater from scrubber effluent also needs to be carried out properly. The operators of such systems should be trained extensively before allowing them to handle these systems. This is because the chemicals involved in these systems have special handling requirements, and should be handled quite carefully. However, the scrubbers are not effective for removing VOCs (Volatile Organic Compounds), and for reduced sulfur compounds, such as dimethyl disulfide.
The common chemicals used in the scrubber for oxidizing hydrogen sulfide and some other reduced sulfur compounds are sodium hydroxide (caustic) and sodium hypochlorite (bleach). The oxidation reactions depend largely on the pH. The optimum pH of the scrubber solution should be within the range of 9.5 to 10.5. In this range, the recirculation liquid absorbs the hydrogen sulfide.
Chemical Scrubbers can effectively eliminate a broad range of odour causing compounds arising from various industrial processes. Industries are widely using this technology to remove malodours effectively. If you want to know any kind of information about this service, please click here and get more.