Technology In-Depth

The AFCO2 Scrubber is being developed to clean the air from industrial smokestacks. The process is elegant:

The majority of existing carbon capture and sequestration technologies are based on the MEA capture process. The dirty air flows through a monoethanolamine solvent that chemically absorbs gasses. The solution is sent to a stripper where it is heated to release almost pure CO2 that is then stored underground in salt deposits, saline aquifers, rock formations, and coals seams or utilized to enhance recovery of depleted oil and gas fields or oil-bed methane. The MEA solution is recycled to the absorber.

Our process offers the following advantages over existing technologies:

• Sales of calcium carbonate offer a profit stream.
• Greater carbon capture and plant efficiency.
• Increased carbon credit sales.
• Only slightly more electrical use than conventional Flu-Gas Desulferization (FGD) wet scrubbers, and water can be reused.
• Suited for retrofitting post-combustion CO2 sources and industrial processes that release CO2.
• Can be integrated with a FGD scrubber to remove sulfur dioxide emissions from industrial smokestacks.

 

The Aqueous-Froth Multi-Pollutant (AFMP) Scrubber will provide a full-spectrum solution for industrial wet scrubbing that will replace flu gas desulphurization (FGD). It will capture a wide range of pollutants from industrial smokestacks, including sulfur dioxide, SO2, mercury, lead, arsenic, and selenium, and particulate matter (PM10 and PM2.5).

The AFMP Scrubber will be installed in-line to clean flue-gas released during industrial burning of coal, oil, or natural gas and during cement, plaster, or gypsum production processes. It will prepare the exhaust gas for the last step of CO2 capture with the AFCO2 Scrubber.

The wet scrubber system is integrated by co-current flow of primary fluids: the flue gas and the transportation liquid. The co-current flow of primary fluids through the system provides a continuous process of evolution and optimization of the chemical composition of both fluids. A reduction of scaling (calcinations) is achieved by optimizing the liquid flow path through the system and by maximizing transportation of solids by fluid flow into settling tanks.

The AFMP Scrubber system:

• Provides a method of CO2 and SO2 recovery, conversion, and sequestration where other methods would not be economically feasible, environmentally responsible, or publicly accepted.
• Produces calcium carbonate and calcium sulfate that can be sold for production of cement, concrete, plaster, and gypsum and offset the cost of carbon.
• Sequesters the relatively small amounts of soluble methyl mercury found in smokestack emissions into concrete, plaster, and gypsum, reducing its environmental impact.

 

We observed how Mother Nature cleans the air during a rainstorm. This process is mimicked in the AFA Filter with Nucleation, where the contaminated air enters the filter and the particles act like the nuclei of raindrops, using principles of nucleation and condensation. Droplets of moisture condense onto particles in the air stream. The particles are captured in droplets that then combine to form a liquid and then are washed out of the airstream. The process achieves full-spectrum capture: particles, liquids, and gaseous pollutants. Clean air and an inert liquid exit the filter.

The AFA Filter with Nucleation is the first foam-bed wet scrubber that forms droplets inside the bubbles of the foam by heterogeneous nucleation to maximize contaminant capture efficiency. In nature, droplets form by heterogeneous nucleation onto contaminants in the air. Droplets increase and decrease in size through an irregular pattern of condensation and evaporation, depending on the ambient conditions around the droplet, until they are heavy enough to fall as rain.

 

The AFA Filter with Nucleation creates favorable conditions for droplet growth by saturating the air with vapor, then cooling the aqueous-froth in order to force a single one-way phase change throughout the volume of the bubbles and the froth column. This process accomplishes the expediency required in chem/bio and other indoor air quality applications. DF200 is Sandia National Laboratory’s patented decontamination foam that they tested for use with the AFA Filter for Nucleation.

As air and dust are drawn into the AFA Filter, it traps high volumes of large to sub-micron size particles. Water, the first level of filtration, grabs onto the dust particles. As the dust becomes saturated, it falls to the bottom of the container. The surface area of the water is increased with the aqueous froth, creating a froth matrix that captures additional dust particles and serves as the second level of filtration. When the bubbles’ aqueous froth contacts the coarse fiber filter element, the bubbles are absorbed and the (drywall) dust settles to the bottom of the bucket. A fourth level of filtration is provided with a fine fiber filter element.

The Aqueous-Froth Air (AFA) Filter has distinct advantages over other filters:

• It doesn’t plug up. It can handle large volumes of dust and extremely small particles.
• It is more efficient. The foam provides greater surface area to capture particles.
• It is scalable. It can work in small rooms or large factories to clean the air you breathe. 

Vac-U-Sand was the first product line of the AFA Filter. Peletex manufactured and nationally distributed a line of vacuum sanding tools for the drywall industry through Grabber Construction Products (2001-2004). The Vac-U-Sand demonstrates high-level capacity to capture and contain the large volume of particulate matter generated during drywall sanding. The system includes an AFA Filter, sanding pole, vacuum hose, and cart, and is powered by an external utility vacuum.

 

 

The Aqueous-Froth Generator is a method and an apparatus that improves the efficiency of an Aqueous-Froth Air Filter.

An array of saturated mesh assemblies interacts with an incoming contaminated air stream. As the air stream flows through the saturated mesh assemblies, an aqueous froth is generated immediately downstream of each mesh assembly. As the froth matrix moves downstream towards the next saturated mesh assembly, the velocity of the air stream causes some of the bubbles to burst. The bursting bubbles rupture into many micro-droplets. The micro-droplets are used together with the aqueous froth to coalesce with or bind with contaminants in the air stream. 

An optional feature is that massive particles greater than three microns in diameter are removed by inertial impaction, and the heavy particles collide with the walls of serpentine shaped vanes of a mist eliminator.