Activated Carbon Fiber Adsorption and Desorption Tower (EHXT Series)

The EHXT series activated carbon fiber adsorption and desorption tower is designed for the purification and recovery of volatile organic compounds from low-concentration, high-air-volume exhaust gas or high-concentration intermittent emissions.

The system uses activated carbon fiber, commonly abbreviated as ACF, as the adsorption material. Through an efficient, safe and reliable adsorption, desorption and recovery process, combined with integrated electromechanical control, the equipment can effectively capture and recover organic compounds from industrial exhaust gas.

Activated carbon fiber adsorption is mainly based on physical adsorption. Because functional groups are present on the ACF surface, a certain degree of chemical adsorption may also occur. Before entering the adsorption tower, the exhaust gas passes through a pretreatment system to remove fine suspended particles, corrosive substances and liquid droplets.

The pretreated exhaust gas then passes through the activated carbon fiber bed. Organic pollutants are adsorbed by the ACF material, while the purified gas that meets the applicable emission requirements is discharged outdoors through the fan.

Adsorption Principle

Adsorption is a process in which molecules from a lower-density substance accumulate on the surface of a higher-density material when two different phases come into contact.

The material that captures and retains the molecules is called the adsorbent. It is usually a porous solid with a relatively high density. The substance being captured is called the adsorbate and is generally a gas or liquid with a relatively lower density.

Adsorption processes can include chemical adsorption, activated adsorption, capillary condensation and physical adsorption. Activated carbon fiber mainly works through a combination of capillary condensation and physical adsorption.

The micropores in activated carbon fiber can be regarded as extremely small capillaries. When gaseous or liquid organic molecules come into contact with the ACF surface, capillary forces cause the molecules to condense inside the micropores.

Physical adsorption is generated by intermolecular forces, also known as van der Waals forces, between the adsorbent and the adsorbate. No chemical reaction occurs during this process. Physical adsorption is rapid, reaches equilibrium quickly and is generally reversible.

Because the micropores of activated carbon fiber open directly onto the fiber surface, organic molecules can enter the pores through a very short diffusion path. Intermolecular attraction continuously draws additional molecules into the micropores until the available adsorption space is filled.

Effective adsorption depends on the relationship between the pore diameter and the molecular size of the organic compound. The pore structure must be slightly larger than the target molecule so that the molecule can fully enter and be retained. A pore that is too large or too small may reduce adsorption performance.

Different raw materials and activation conditions can therefore be used to produce activated carbon fiber with different pore structures for the selective adsorption of different organic compounds.

System Structure

The activated carbon fiber adsorption and recovery system uses a high-quality stainless steel housing. Each adsorption chamber contains a specified number of annular fixed beds wrapped with activated carbon fiber felt.

Depending on the required treatment capacity and adsorption efficiency, the system can be configured as a single-stage, two-stage or multi-stage adsorption process. Multiple adsorption chambers can be connected in parallel or in series through pipelines and automatic valves.

The chambers operate in alternating cycles so that adsorption, desorption, regeneration, drying and cooling can proceed continuously.

Process Stages

Activated Carbon Fiber Characteristics

• Highly developed pore structure with a large specific surface area
• Predominantly microporous structure with only a small proportion of transitional pores
• High ratio of effective adsorption pores
• Fine fiber diameter and pores that open directly onto the fiber surface
• Short adsorption and diffusion paths
• Large and uniformly distributed contact area
• Uniform pore diameter and narrow pore-size distribution
• Good adsorption selectivity for different organic compounds
• Flexible material forms, including yarn, cloth, felt and paper

These characteristics give activated carbon fiber a high adsorption capacity, rapid adsorption and desorption rates and the ability to selectively capture and recover different volatile organic compounds.

Key Advantages

Innovative System Design

• The system uses cylinder-operated damper valves suitable for handling large exhaust gas volumes. Their cost is significantly lower than pneumatic butterfly valves of comparable size.
• A three-way bypass valve is installed before the adsorption system. If the equipment requires maintenance or experiences a fault, workshop production can continue without interruption.
• For systems requiring fan pressurization, the main fan is positioned before the three-way bypass valve. The fan can continue operating during maintenance or equipment shutdown, maintaining active workshop exhaust and improving the production environment.
• The annular fixed-bed structure is wrapped with activated carbon fiber felt. This design increases the effective ventilation area, reduces pressure resistance and improves exhaust gas treatment capacity.
• The equipment offers flexible selection and process configurations. For organic compounds that are difficult to adsorb, a recirculation system can repeatedly pass the exhaust gas through the adsorption bed to improve removal efficiency.
• The PLC control system follows a programmed sequence for adsorption, desorption, regeneration, drying and cooling. Even under frequent switching conditions, all system components operate in a coordinated and fully automatic manner.

Applicable Industries

The EHXT activated carbon fiber adsorption and recovery system is suitable for exhaust gas treatment and organic solvent recovery in the following industries:

• Petrochemical processing
• Pharmaceutical and chemical manufacturing
• Pesticide production
• Industrial coating and lamination
• Painting and surface coating
• Packaging and printing
• Leather manufacturing
• Microfiber and synthetic leather production
• Ultra-high-molecular-weight polyethylene fiber production
• Tank loading and oil storage facilities

The system captures organic compounds from industrial exhaust gas for recovery and reuse, helping reduce solvent consumption, atmospheric emissions and environmental pollution.

Recoverable Organic Compounds

Typical Application Projects

How the Continuous Operating Cycle Works

1. One adsorption chamber captures VOCs from the incoming exhaust gas.
2. Another saturated chamber begins steam desorption and regeneration.
3. The desorbed organic vapor enters the condenser for liquid recovery.
4. The regenerated ACF bed is dried and cooled with purge air.
5. The automatic valves switch the chambers into the next operating cycle.

This alternating operation allows the system to continuously treat industrial exhaust gas while recovering valuable organic solvents.

Frequently Asked Questions

What is an activated carbon fiber adsorption and desorption tower?

It is a VOC treatment and solvent recovery system that uses activated carbon fiber to adsorb organic compounds from industrial exhaust gas. The captured compounds are subsequently removed through steam desorption, condensed and recovered as liquid solvents.

What working conditions are suitable for the EHXT series?

The system is suitable for low-concentration, high-air-volume exhaust gas and high-concentration intermittent emissions containing recoverable organic compounds.

What is the difference between activated carbon fiber and granular activated carbon?

Activated carbon fiber has pores that open directly onto the fiber surface, providing a shorter diffusion path, faster adsorption and desorption speed and a relatively high effective adsorption area.

Can the captured organic solvents be reused?

Yes. After steam desorption and condensation, the recovered liquid mixture can be separated by gravity, distillation or rectification. Suitable recovered solvents may be returned to production after the required purification process.

Can the system operate continuously?

Yes. Multiple adsorption chambers can operate alternately. While one chamber performs adsorption, another can undergo desorption, regeneration, drying or cooling.

Can ES Air customize the process configuration?

Yes. ES Air can configure the system according to exhaust gas volume, VOC concentration, solvent composition, emission pattern, recovery requirements and installation conditions.

Customized VOC Adsorption and Solvent Recovery Solutions

ES Air provides activated carbon fiber adsorption, desorption and solvent recovery systems for industrial VOC treatment applications.

Equipment configuration should be determined according to the exhaust gas composition, concentration, air volume, temperature, humidity, emission pattern and solvent recovery requirements.

Contact ES Air for process evaluation, equipment selection, engineering design and customized VOC recovery solutions.

SEO Brief: The ES Air EHXT Series Activated Carbon Fiber Adsorption and Desorption Tower is designed for industrial VOC purification and organic solvent recovery. Using regenerable activated carbon fiber, steam desorption, condensation recovery and automatic PLC control, the system is suitable for petrochemical, pharmaceutical, coating, printing, leather, synthetic fiber and oil vapor recovery applications.