What is a chemical filter and what problems are it mainly used to solve?

Chemical filters are a type of air purification device that specifically handles gaseous pollutants. It is different from the common HEPA and ULPA - those filters deal with particles, while chemical filters deal with gas molecules.

At its core is a layer of adapted adsorption or reaction media. When the airflow passes through the medium, the target gas is adsorbed, trapped or reacted, thereby reducing the concentration in the outlet air. Acidic gases, alkaline gases, organic vapors, and odor components may all be treated by it. But what exactly it can handle does not depend on the name 'chemical filter', but on what media is inside and which gases the media has been certified for.

Distinguish the objects to be processed first

There are many types of gaseous pollutants, and their properties vary widely.

Acid gases : sulfur dioxide, hydrogen chloride, nitrogen oxides, etc. Commonly found in external industrial emissions, specific processes or laboratory environments.

Alkaline gas : ammonia, amines, etc. It can be introduced by cleaning agents, certain material releases or external sources.

Organic vapor : solvent volatiles, formaldehyde, toluene, etc. Paints, adhesives, and cleaning processes are common sources.

Odor components : usually not a single substance, but may be mixed with sulfides, ammonia, organic acids, etc. For deodorizing projects, you must first understand the main ingredients, and you cannot choose the medium based on smell alone.

Different target gases require matching different media. Just because a medium is effective for a certain type of organic matter does not mean it is equally effective for acid gas or ammonia. When selecting, the gas composition, concentration, temperature and humidity conditions must be provided together to confirm whether the medium is suitable.

It's not the same thing as a particle filter

Many people compare chemical filters with HEPA and ULPA, but in fact they solve different problems.

HEPA/ULPA : Intercepts particulate matter. Efficiency ratings describe the ability to filter particles of a specific particle size.

Chemical filters : Process gaseous molecules. The evaluation indicators are target gas removal efficiency, adsorption capacity, penetration time, etc.

The two often need to be used together. In clean rooms or equipment, particle filtration and chemical filtration are often set up in layers and perform their own duties. Good particle filtration can reduce dust covering chemical media; good chemical filtration can reduce the impact of gaseous pollution on the process. But no layer can replace another layer.

Specific products can be referred to the chemical filter product range . Description of

Processing capabilities are formed only after being installed into the system

The chemical filter itself has no power, it relies on a fan to push the air flow through the media. So the actual effect depends not only on the medium but also on the system conditions.

The air volume must match. The air volume passing through the filter material is too high, and the contact time between the gas and the medium is insufficient, so the removal effect may be reduced; the air volume is too low, and the processing capacity is insufficient.

The seal must be reliable. The frame bypass will allow untreated air to bypass the filter material, and the outlet concentration will naturally not decrease.

The installation location must be correct. Filters should be placed where contaminated air must pass. If the source of contamination is downstream of the filter, or the airflow is bypassed, the best media will not be effective.

Maintenance needs to keep up. The replacement of chemical filters is based on gas processing capacity consumption, not pressure difference. A normal pressure difference does not mean that the outlet is still up to standard.

Common application scenarios

Chemical filters have different uses in different industries.

Semiconductors and precision manufacturing : control AMC (air molecular pollution) and protect key processes such as photolithography and etching. Acid and alkali gases and organic matter may be targets.

Pharmaceutical and biomedicine : Aseptic filling and packaging areas may be affected by external odors, and filter sections need to be configured for specific gases.

Data centers and computer rooms : Assess gaseous corrosion pollution and protect the reliability of electronic components.

Food and cosmetics : control odors in the production environment and improve the working environment and product quality.

Laboratory and exhaust system : To deal with the specific gases generated during the experiment, the medium needs to be selected according to the nature of the pollutants.

Different scenarios have different requirements for filters. When selecting, the specific target gas, air volume, environmental conditions and acceptance methods should be combined, and not just the industry name.

What to confirm before choosing

If the project requires a chemical filter, it is recommended to clarify the following items first.

Pollutant components : What kind of gas is it specifically, what is the concentration range, and whether there is mixed pollution.

Processing air volume : What is the air volume passing through the filter section and whether it is stable.

Environmental conditions : temperature, humidity, and whether there is a risk of condensation.

Export target : what concentration level is expected to be achieved and what method is used to detect it.

Installation space : available dimensions, interface forms, maintenance access.

The more complete this information is, the more targeted the selection will be. When key conditions are lacking, air sampling or trials can be arranged first and then the plan is determined.

Involving device-side applications such as FFU with chemical filter or For MAU box-type chemical filters , it is also necessary to check the interface, resistance, and control method of the filter section and the air supply equipment.

Project judgment example

A data center computer room showed signs of circuit board corrosion, but the particle filtering system was operating normally.

The investigation found that there were industrial emissions near the fresh air inlet and there were acidic gases in the air. The particle filter has no ability to process gas, so the corrosion problem cannot be solved.

Adjustment direction: First detect the relevant gas concentrations in the fresh air and the computer room, and then evaluate adding a chemical filtration section to the fresh air section or adjusting the inlet position. The selection of the filtration section should be based on the detected acidic components, rather than randomly selecting an activated carbon.

This case shows that the problem solved by the chemical filter must start from the source of pollution and the target gas. No matter how good the particle filtration is, it cannot stop gas molecules.

Key points for selection and acceptance inspection

About Aili Industrial’s chemical filtration packages

Aili Industrial provides chemical filter product series and related clean air equipment. You can compare the FFU package, box type, flat type and V-type products based on the target gas and installation location, and then check the air volume, resistance and detection conditions. Aili Industry has independent manufacturing capabilities in the R&D and production of motors, fans, control systems, sheet metal, filters and complete machine assembly, which can be used to connect the configuration of filter sections and air supply equipment; the specific gas applicability and performance still need to be confirmed based on the model, filter material and usage conditions.

Related products:Chemical filter product range . First clarify the pollution and protection goals, then check the product conditions, and finally verify the on-site effect.