Removing hydrocarbons and benzene from air emissions at foundries
New regulations have come into force that impose stricter limits on air emissions from foundries and smitheries. DESOTEC provides mobile, sustainable filtration solutions to steel and metal companies seeking to purify their emissions of compounds including petroleum hydrocarbons (PH) and benzene, as this case study from The Netherlands demonstrates.
Key takeaways
- We design optimal filtration set-ups for our clients, always taking into account total cost of ownership as well as effectiveness.
- We partner with customers throughout the lifespan of a project, helping them find solutions to any unexpected issues that may arise.
- Our solutions are modular and able to flex in with changing regulations or production parameters.
The challenge
A major company has a foundry in The Netherlands where it manufactures steel, from iron ore through to finished products. Foundry and smithery processes include annealing and cold mill, where the steel is heated and made more malleable, and rolled into sheets.
Under the Best Available Techniques (BAT) Reference Document for the Smitheries and Foundries Industry (SF BREF), updated as part of the revision of the Industrial Emissions Directive (IED), such plants are now subject to more stringent emissions limits. These are aimed at protecting the environment, with a new focus on odour management.
This Dutch foundry has two air flows coming from its annealing facilities, each with a flow rate of 1 600m³/h. Both contain high concentrations of petroleum hydrocarbons (PH) and benzene, which carry serious occupational health and environmental risks.
The company already had a contract with DESOTEC to treat air emissions from a packaging line that contained the same compounds. We were in discussions about how best to tackle the emissions from the annealing plant when the environmental authorities stepped in.
The company was under pressure to resolve the issue fast, so turned to DESOTEC’s mobile filtration solutions.
The solution
Standard treatments for such foundry emissions include Regenerative Thermal Oxidisers (RTOs) and activated carbon filtration. However, our calculations showed that, due to the composition of the gas, neither technology would be sufficient on its own.
If an RTO was placed as a standalone treatment, it would need to be heated to extremely high temperatures to handle the high concentrations of PH in the flow. This would require huge amounts of gas, which would be very costly.
Therefore, our engineers worked with the customer to design an optimal filtration solution that was both effective and took into account Total Cost of Ownership (TCO).
Emissions are first passed through two lines of filters: two AIRCON HC-XL filters as a pre-treatment to remove PH and larger hydrocarbons, such as benzene; then two HC-XL filters to provide back-up.
Treated emissions are then passed through an RTO to remove smaller hydrocarbons such as methane, propane and ethane. The air is then safe for discharge to the environment.
The results
The system was installed in early 2022, and has provided effective treatment ever since. All the filters are working well, and the customer is delighted with the set-up. The company has now contacted us to provide treatment for sulfur oxide (SOx) emissions at the same foundry.
DESOTEC always offers customers ongoing support. At this foundry, our engineers are helping overcome a minor issue that sometimes arises during the colder winter months, when poly(ethylene-ran-hexene) (PEH) in the gas stream tends to condensate in the filter distributor, potentially causing blockages and pressure drop. Resolving this has been a simple matter of exchanging the filters more frequently, and we are now working with the customer on optimising the set-up. Our filtration solution remains the most cost-effective technology for this application.
Filter exchange is a swift and simple process requiring little to no production downtime. As part of our full-service solution, we handle all filtration waste, removing it from customers’ sites in closed units. We transport it to our facilities and destroy all compounds in our furnaces. Wherever possible, carbon is reactivated for reuse.
Our mobile filters are supplied on a rental basis. As they are modular, filters can be added or removed to meet changing production requirements or comply with stricter legislation, such as the new SF BREF.
This is now a highly fruitful partnership for both the customer and DESOTEC, which involves ongoing discussions about future requirements and projects. We look forward to continuing our work at this foundry for many years to come.
The updated SF BREF imposes stringent new standards on smitheries and foundries across Europe. DESOTEC can provide rapid solutions for companies in the metal and steel sectors, purifying emissions of a range of compounds, including odours.
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Our unique service
Our closed-loop, full-service model is as unique as your business needs. We’ll define the right filtration setup and safely recycle filtration waste, making it easy to go green. -
Hydrocarbons
The manufacture of fossil fuel based products emits hydrocarbons, resulting in odor and environmental challenges that require treatment. -
Steel and Metal Industry
Simple purification solutions for air emissions and wastewater, helping heavy industry tread more lightly on the planet.