Why should chemical filters be selected according to the target gas?

In the discussion of chemical filter selection, the phrase 'select according to target gas' is often mentioned. But why this is done, some projects may not delve into it.

The reason is simple: different gaseous pollutants require different media to handle. Just because a filter material is effective for a certain gas does not mean it is equally effective for another gas. If only 'deodorization', 'air purification' or 'VOC treatment' are written during model selection, the supplier cannot confirm what media should be configured, and there is no clear basis for judgment during project acceptance. For specific configuration methods, please refer to the chemical filter product range . Description of

Medium is not the universal answer

The core of chemical filtration is the interaction between the medium and the target gas. This effect is selective, and not all gases can be effectively treated by the same medium.

Physical adsorption. Media such as activated carbon adsorb gas molecules through surface pores. This method is more effective for some organic matter, but the adsorption capacity is affected by gas properties, concentration, temperature and humidity. It may be effective for low concentration, weakly polar organic matter, but has limited effect on highly polar or low molecular weight gases.

Chemical adsorption or reaction. Impregnated media, or specialized chemical adsorption materials, capture target gases through chemical reactions. Such media are usually designed for specific gas classes, such as acid gases, alkaline gases, or certain organic compounds.

Different media have different application ranges. A medium for organic vapors may have little effect on ammonia; a medium for acid gases may not be of much help with organic matter. Therefore, the first step in selection is to confirm what the target gas is.

The report must correspond to the gas

When you get a performance report for a chemical filter, you need to confirm what gas it measures.

Test gases should match project objectives. If the report measures toluene and the project needs to control ammonia, this data cannot be directly used to judge the effect of ammonia treatment.

The test conditions should be close to actual working conditions. Air volume, inlet concentration, temperature and humidity, and gas mixing conditions will all affect the media performance. The data in the report were obtained under specific conditions and cannot be copied directly without the conditions.

There are also differences between filter material samples and finished product reports. The sample test reflects the performance of the material itself, and the finished product also considers the effects of filling, sealing and airflow distribution. For specific inspection project implementation methods, please refer to Discussion of why chemical filter performance reports list specific target gases .

Data for single gases cannot be directly extrapolated to mixed pollution. If there are multiple gases in the gas stream, different components may compete for adsorption sites, or some components may react preferentially. In this case, it needs to be re-evaluated for mixed conditions.

Selection input determines solution boundaries

In addition to the gas name, there are several inputs that affect the scheme design.

What is the object of protection? Is it to improve personnel's sense of smell or to protect precision equipment or process products? Depending on the target, the allowed outlet concentrations and detection methods may differ.

Inlet concentration range. The gas concentration will affect the medium capacity and service life. High concentration scenarios may require pretreatment or more frequent replacement.

Operating environment conditions. Temperature, humidity, and whether there is a risk of condensation will all affect the state of the medium. In a high-humidity environment, some media may absorb moisture and degrade in performance, so the applicability needs to be confirmed.

Air volume and system conditions. The amount of filter material and structural form are determined by the air volume, available resistance, and installation space of the filter section.

Once these inputs are complete, the supplier can determine which medium, dosage, and structure are more suitable. When key information is missing, recommendations can only be based on default conditions, and the actual results may deviate from expectations. involving The fresh air project of MAU box-type chemical filter also needs to consider the inlet location, seasonal changes and pre-filtration configuration.

Project judgment example

A certain project needs to deal with the gas generated by the cleaning process, and a conventional activated carbon filter was initially selected.

After running it, it was found that some of the odors had improved, but still remained. Testing confirmed that the main residual component is ammonia, and conventional activated carbon has limited adsorption capacity for ammonia.

Adjustment plan: After the original filter section, add special media for alkaline gas. Before configuration, recheck the ammonia concentration, air volume, temperature and humidity conditions, and confirm the media type and dosage. After adjustment, the outlet concentration meets the requirements.

This case illustrates: When selecting, you must first confirm the target gas and then select the corresponding medium. If you only rely on experience or generic labels for selection, key ingredients may be missed. involving FFU supporting chemical filter also needs to check the media plan according to the target gas. The local circulation project of

Key points for selection and acceptance inspection

About Aili Industrial’s gas selection support

The premise of selecting a chemical filter is to clearly explain the target gas and working conditions. The more complete this information is, the more targeted the media configuration will be.

Aili Industrial has independent manufacturing capabilities in filters, motors, fans, control systems and sheet metal processing, and can provide chemical filter product series and supporting air supply equipment. For projects that require target gas selection, the gas composition, concentration, temperature and humidity, air volume and installation conditions can be combined to assist in checking the filter material type and structural configuration. When the filter is matched with MAU, FFU, EFU and other equipment, the resistance, interface and maintenance methods can be confirmed uniformly.

Related products:Chemical filter product series、MAU box chemical filter、FFU comes with chemical filter . Provide a target gas list and system conditions when enquiring, to help confirm the appropriate media solution. The specific selection is subject to the technical documents and test results confirmed by the project.