Many industrial operations produce an atmosphere laden with dust and Volatile Organic Compounds (VOCs). Or because the operation simultaneously emits these dusts and VOCs. Or because the workshop or industrial shed houses parallel operations that independently generate dust or VOCs , which then mix with the ambient air.
What’s more, some operations produce odor nuisances linked to VOC or dust emissions. Moreover, a large proportion of the VOCs emitted into the workshop air come from the solvents used in these operations. However, most solvents are flammable, creating an explosive atmosphere (ATEX). Fine particles suspended in the air have combustible potential. The gaseous VOC-dust mixture increases the ATEX risk.
For the manufacturer, this means treating both VOCs and dust. In fact, regulations require it to prevent the health and safety risks implied by their presence in the building’s atmosphere.
Depending on the production context, the industrialist may choose to call on an assembly of treatment devices, or opt for a filter that combines in-house dust and VOC treatment technologies. In general, VOC treatment alsoeliminates odours. In addition, to respond to the ATEX risk, the industrialist will equip himself with equipment that conforms to the ATEX zone in which it will be placed.
After an overview of some of the industrial sectors and activities that produce atmospheres combining VOCs and dust, often odorous or explosive, we’ll look at possible treatment techniques. Then we’ll look in detail at VOC and dust emissions by industry, as well as the olfactory nuisances and ATEX risks they generate.
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Some examples of industrial processes emitting dust and VOCs
Many industrial processes can emit both airborne particles (dust) and volatile organic compounds (VOCs). This may involve the simultaneous emission of VOCs and dust, or combined emissions from parallel or successive tasks performed in the same volume. Here are a few examples:
Chemical industry
Chemical plants manufacturing organic chemicals can emit VOCs during the synthesis, polymerization, handling and storage processes. In addition, particles can be generated during the handling of solid raw materials or the production of powdered products.
Automotive industry
Activities such as paint application, welding and grinding in automotive production can generate both metallic or plastic fine dusts and VOCs from the paints, solvents and adhesives used.
Wood industry
Sawing, sanding and wood treatment operations can release wood particles and VOCs from the chemicals used in wood treatment and finishing.
Plastics industry
The production of plastics, particularly by injection molding or thermoforming, can result in emissions of plastic particles and VOCs from the base materials and processing agents.
Paint and coatings industry
Painting, coating and finishing processes in sectors such asconstruction, aerospace and marine can release both particulates and VOCs from paints, solvents and thinners.
Food industry
Some food processing activities, such as roasting, drying and frying, can generate food particles and VOCs from cooking and processing.
These examples illustrate how certain industrial volumes can contain both dust and VOCs, underlining the importance of controlling and reducing these emissions to protect human health and the environment.
What technologies are needed to treat dust and VOCs?
There are several types of technology available for the joint treatment of dust and volatile organic compounds (VOCs). Here are a few frequently used ones.
Adsorption on activated carbon
Activated carbon adsorption systems are designed to trap VOCs by making them adhere to a structured surface of activated carbon. These systems can be combined with other filtration technologies to treat both dust and VOCs.
Bag filters
Baghouses use fabric filter bags to capture airborne particles. Some models are also equipped with absorbent materials that can trap VOCs. These systems can be effective in treating both dust and VOCs, but sometimes require pre-treatment to improveVOC capture efficiency.
Combination systems
Some air pollution control systems combine several technologies, such as bag filters andactivated carbon adsorption, to effectively treat both dust and VOCs.
Electrostatic precipitators
Electrostatic precipitators use an electrical charge to capture airborne particles. Some models can also be fitted with adsorbent materials to capture VOCs. Electrostatic precipitators can be effective in treating both dust and VOCs, but may require regular maintenance to maintain their efficiency.
Biofiltration systems
Biofilters use microorganisms to break down VOCs into less harmful compounds. Some biofilters can also be fitted with filter media to capture airborne particles. Biofiltration systems can be effective in treating both dust and VOCs, but may require specific conditions to maintain the activity of the microorganisms.
It is important to select the technology according tothe specific characteristics of the process and the nature of the contaminants present in industrial emissions.
Dust collectors with integrated VOC filtration
A dust collector combining bag filters andactivated carbon adsorption treats both dust and volatile organic compounds (VOCs). It’s an integrated system operating in several processing stages. Here’s how this type of dust collector works
Dust capture stage
The system begins by filtering airborne particles using bag filters. Filter bags are generally made of a fabric or porous material whose holes have a diameter smaller than the size of the particles in the effluent gas. Dust-laden air passes through filter bags, where particles are trapped on the surface or in the fibers of the material. The air, filtered of dust, leaves the bag filters still loaded with VOCs.
VOC capture stage
After passing through bag filters, the dust-filtered air is transferred to a bed of activated carbon or other adsorbent material. The material traps VOC molecules on its surface, acting like a kind of chemical sponge. In the end, the air is purified of both dust and VOCs before being exhausted.
Maintenance and care
Bag filters must be cleaned or replaced regularly to maintain their efficiency. To remove accumulated particles, filters are cleaned by shaking or blowing out with compressed air, either manually or automatically via a module integrated into the dust collector.
The activated carbon bed also needs to be replaced or regenerated periodically, as its adsorption capacity diminishes over time.
Control and monitoring
Typically, a dust collector is equipped with sensors and monitoring devices to control its efficiency, including dust and VOC levels in the filtered air. The data collected by these sensors will be used to adjust system parameters and ensure optimal operation.
Advantages of combined dust and VOC filter
This type of combination dust collector offers the advantage of treating both dust and VOCs, making it an effective solution for many industrial applications where both types of contaminant are present. Combined dust-VOC mobile filters have the advantage of being easily adaptable to changing workload configurations.
Conclusion: the importance of simultaneously treating dust and VOC emissions
In industry, it’s important to install dust collection and VOC control systems , such as dust collectors combining baghouse and activated carbon capture technologies, or a combination of independent devices, e.g. baghouses and activated carbon filters, as well as appropriate ventilation systems, to simultaneously manage dust and VOC emissions. This helps maintain a safe working environment that complies with air quality regulations. Odor nuisance is managed through VOC filtration. ATEX risks can be prevented by choosing an ATEX-marked device.