Activated carbon is a highly porous inert material with a very large internal surface area (700-1500 m²/g). The high surface area makes it ideal for adsorption. Activated carbon is produced from materials containing amorphous carbon, such as wood, coal, peat, and coconut shells. It is created through a thermal process where volatile components are removed from the carbonaceous material (feedstock) in an oxygen-rich environment. Special treatments are applied to create a unique pore structure that determines the adsorption capacity and characteristics of the activated carbon.
In an activated carbon adsorber, the gas stream is passed through the activated carbon, where the components to be removed are adsorbed onto the carbon until saturation is reached. Once the activated carbon reaches its saturation point, it is replaced or regenerated.
Typically, when the saturation point is reached, the spent activated carbon is sent to a disposal facility and can be reused after regeneration.
The saturation level is usually expressed as g/kg of activated carbon. The saturation level is determined by the concentration of the components present in the air. In experimental setups, adsorption isotherms can be created to show the relationship between the partial pressure of the components in the air and the amount of component that can be collected per gram of activated carbon.
The isotherm of activated carbon is linear, and the capacity increases proportionally with higher partial pressures. This means that at a specific temperature, activated carbon has a higher adsorption capacity at higher inlet concentrations compared to lower inlet concentrations. However, at higher temperatures, the adsorption capacity will decrease.
As a reference, an adsorption capacity of 20-25 g solvent (expressed as carbon) per 100 g of activated carbon can be achieved during effective adsorption. If the component is a weak adsorbate, the capacity will decrease with increasing temperature or humidity.
Filled Bed Adsorber: Single-bed adsorbers are designed in horizontal or vertical configurations. Multiple adsorbers consist of one or several stages in panel form within the vessel. The system includes two or more separate adsorbent vessels, allowing regeneration by vapor reactivation when the air flow reaches the saturation point due to the adsorption of pollutants.
Carbon Filter Adsorber: When the airflow reaches saturation, it can be easily replaced with fresh ones.
Adsorption through activated carbon can occur using filled cartridges, as carbon in a packed bed, or through powdered carbon injection combined with a fabric filter.
In low-flow applications, activated carbon is sometimes provided in pre-filled filter cartridges that are periodically replaced in the filter installation. In systems requiring larger amounts of activated carbon, a bed with added activated carbon granules is used. This can be implemented as a container system. In high-flow and low-concentration applications, powdered activated carbon is sometimes added and then filtered. The latter is typically used for the removal of dioxins. If dry lime absorption is already present, a combination of lime and activated carbon is also injected to capture acidic components as well as dioxins and VOCs.
After the carbon bed becomes saturated with pollutants, it is possible to regenerate the carbon through heating or chemical washing in order to restore the majority of its activity. However, certain pollutants such as VOCs, dioxins, or furans are not typically recommended for carbon adsorption due to the complexities of disposal or regeneration processes. The applications engineers at MDSJ AIR Equipment can provide specific recommendations.
A wide range of adsorbents: A wide range of adsorbents are used as filling materials, such as carbon, zeolite, and synthetic polymers. Capacities of 150,000-200,000 m3/h can be installed for a single unit. Up to 99% efficiency can be achieved.
The body structures can be made of various materials, including carbon, steel, stainless steel, PVC, HRP, FRP, CTP, PP, and other materials.
The systems are delivered with complete instrumentation and electrical controls.
MDSJ Carbon Adsorbers are made from corrosion-resistant materials, especially PP, FRP, and stainless steel.
MDSJ Carbon Adsorber features a standard or staged carbon bed. The carbon depth and specific type of carbon can be selected specifically to maximize performance for the desired service conditions and minimize operating costs.
Complete systems can be supplied, including fans, ventilation ducts, control panels, and instruments.