Explosive solid fines filtration

Date: 30-04-2020

Royal Dahlman has been awarded with a challenging contract for a newly built specialty chemicals plant in Asia. This contract builds on an established record for Royal Dahlman in this niche market of plastics production, dating back to 1996.

In close cooperation with our Dutch partner, licensor of the most advanced solidification technology, and our local partner taking care of the fabrication, installation and start-up of the plant, Royal Dahlman will provide the know-how and engineering, as well as the proprietary hardware for a large bag house filtration system, removing synthetic organic dust fines from cooling air. One of the main challenges of this specific application is to provide a reliable filtration solution to the customer, that also guarantees the safety of personnel working in the plant. The product being filtered in fact has extremely high explosive characteristics.

Inside a dust filtration system there is a high concentration of solid fines especially immediately after the filter media are automatically cleaned in situ (during operation). When a cloud of fine solid particles in air ignites, it will rapidly combust and dust explosion will take place. The speed with which the flames will propagate through the cloud of combustibles can vary from 10m/s up to more than 100m/s.

Compared with explosives, where the flame speed is measured in km/s, this speed is relatively slow. This makes it possible to extinguish the explosion before it can take disastrous proportions. To accomplish this, the explosion is detected in a very early stage and an extinguishing agent is injected extremely quickly. Immediately following ignition, the explosion is detected either as a fast growing fireball, or by the rising pressure caused by the combustion gases. From the very moment a dedicated control unit receives the signal from one of the explosion detectors, it activates the suppressors. Only a few milliseconds later the injection of the extinguishing agent starts and the fireball is smothered, hence extinguished. This limits the explosion pressure (Pred) to a few tenths of a bar, substantially lower than the maximum pressure obtained by an explosion that develops uninhibited. It takes no imagination at all to understand that a bag house filter can be a potential bomb if it not well-designed and if it is not provided with reliable and proven explosion protection technology.

Having delivered multiple of these very specific and advanced bag house filter packages, we are proud that Royal Dahlman has been selected by this new customer, based on our proven performance and for offering the most reliable and safe filtration technology available.