AeroScrub Emission Control Systems

For hospital and hazardous waste incinerators
and waste-to-energy plants

Designed specifically to meet the air pollution requirements
for incinerator applications.

With significant cost savings over conventional scrubbing systems.
Now there’s a new flue gas system that meets air pollution control and local government restraints on airborne emissions, and the economic constraints of your waste management facility.

From small hospital incinerators, handling as little as 300 lb/hr, to large waste-to-energy plants, processing 1000 tons/day, the new AeroScrub™ System has been designed to offer all the effectiveness and efficiency of the best wet or dry scrubbing systems… but at a much lower cost.

The disadvantages of current flue gas processing technology.
To understand why the AeroScrub System does a better job at a lower cost, consider standard wet and dry scrubbing technologies.

With a wet scrubbing system, the gas stream enters the scrubber at temperatures of 1000-1500° F. However, the water that is injected to remove acids and particulate lowers the temperature of the flue gas below the acid dew point. Therefore, the scrubber must be fabricated from very expensive specialty metals; otherwise the system would not stand up to the combination of high temperature and corrosive conditions.

To meet codes on heavy metal particulate emissions, wet scrubbing systems produce a large pressure drop in the flue gas stream. Even their wet scrubbers cannot meet the codes. To overcome this pressure drop, these systems require large induced draft fans. 

These fans are expensive to operate; in fact, the AeroScrub System can typically save you $5,000 per year/per 1000 cfm (cubic feet per minute) of gas, or more. Furthermore, the possibility of a failure in the caustic feed system means this fan must also be fabricated of expensive corrosion resistant metal.

Finally, there’s the wet effluent generated by a wet scrubbing system. This is another costly problem you simply don’t have to deal with in an AeroScrub System.

In dry scrubbing systems, flue gas enters a spray dryer where a slurry of slaked lime is injected to neutralize acids. Because of the chemical reaction of the acid gas in the dryer, 80 to 95% is converted to solids that can then be removed, along with other particulate, by a baghouse collector.

Relatively speaking, the dry effluent in a dry scrubbing system lowers operating costs. However, dry scrubbing systems require large initial capital investments. In fact, dry scrubbers are typically beyond the budgets of all but the largest waste management facilities. Plus, the lime handling systems required by the dryer are very maintenance intensive.

AeroScrub combines the best of wet and dry processes.
For hospital incinerators and other small units. In the AeroScrub System, as shown below, incinerator flue gas passes through a heat recovery boiler where waste energy is recaptured to product steam for heating or process applications. In addition to providing cost-free steam, the heat recovery boiler reduces the temperature of the exhaust gas stream to approximately 425° F.

At this point, calcium hydroxide is injected directly into the gas stream using either air or steam as the conveying medium. (Steam injection* offers the advantage of improving the stoichiometry of the reaction, requiring less calcium hydroxide for a given amount of acid.) The reaction of HCL with calcium hydroxide reduces concentrations by up to 90%. More expensive chemicals, such as sodium bicarbonate can increase the removal efficiencies even more. This is only the first stage of the AeroScrub system. However, for many small units and most hospital incinerator jobs, this first phase is sufficient to provide a flue gas system that meets all applicable codes.

Waste to energy and other large systems. For larger or more critical jobs, a down-stream wet scrubbing unit removes most of the small amount of acid remaining. Typical system performance will achieve HCL or SO₂ removal down to less than 30 parts per million. The effluent from this wet scrubber is neutralized with sodium hydroxide and then injected upstream and evaporated. As a result, there is zero liquid discharge to deal with in this system.

In this system, 30,000 cfm of gas with hazardous solvents and toxic vapors are incinerated at 1400° F. The flue gas contains high concentrations of halogen acids and submicron metal oxide fumes. Dry sodium bicarbonate reacts with the acid gases and the inert solids discharged from the baghouse are suitable for landfill disposal. The AeroScrub Emission Control System combines the best features of wet and dry scrubbing to give you a low-cost system suitable to a variety of incinerator or waste-to-energy applications. AeroPulse … Better answers to burning questions.

For 35 years, AeroPulse has been designing and fabricating air pollution control systems that meet or exceed federal and local air quality standards.

Most AeroPulse dust collectors incorporate reverse pulse jet cleaning and felt media. Pulse jet technology eliminates the need for mechanical shakers and compartmenting valves to give you a lower cost collector that requires less maintenance.

Felted media allows higher air-to-cloth ratios than woven bags so collectors are smaller and less costly.

Every AeroPulse air pollution control system is custom engineered for the temperature, gas flow, chemistry and particulate conditions of the specific application. Find out how the AeroScrub System can provide you with an effective, cost efficient answer for your incinerator or boiler.