Problem:
- risk of sugar dust explosion in a beverage manufacturing plant
- need to adapt the plant to the requirements of the ATEX Directive
- slenderness of the silos requiring the selection of economically justified solutions
- need to update the EPD in the light of significant changes in the scope of explosive safety
Solution:
- selection of appropriate explosion protection systems adapted to the technical conditions to protect the silos and the related transport systems against the effects of a sugar dust explosion (delivery, installation, commissioning, service)
- update of the EPD to include the new explosion protection system
Sugar storage silos are part of the production facility, typical in the beverage industry. As sugar dust poses a serious risk of explosion, the silos and their associated transport systems must be effectively protected against the effects of an explosion.
Recommendations of the EPD indicating the need to upgrade the sugar silos
One of the largest beverage producers came to our company with a request to upgrade two sugar silos in order to adapt the plant to the requirements of the ATEX Directive. This was a result of the recommendations of the previously prepared Explosion Protection Document. As a result of the study, it was found that the plant does not have an explosion isolation system for the pneumatic transport between the silo and tanker and that it does not have an explosion decoupling system between the silo and the rest of the process system. In addition, the decompression area on the silos was found to be too small and had to be expanded to meet the requirements of EN 11491.
Adaptation of the plant to the requirements of the ATEX Directive – scope of modernisation
Initially, we considered protecting the silos by installing an HRD suppression system, but due to their slenderness, such a solution would require the use of a large number of HRD cylinders with a suppression agent, which would not be economical.
Therefore, we decided to increase the decompression area both on the side walls and on the roofs of the silos. This required appropriate calculations. As it was important for the client that the upgrade did not reduce the usable volume of the silos, we made special adapters which allowed the panels to be installed at the correct angle.
For the pneumatic transport between tanker and the silo, we used the HRD explosion decoupling system. The same protection was also installed on screw conveyors, which had been replaced by the client with ATEX-compliant ones as part of the deployment of the EPD recommendations.
In order to capture the ferromagnetic impurities from the sugar supply, which could become a source of ignition for the explosive atmosphere and also contaminate the product, we provided for magnetic separators for the systems for loading the silos from tankers.
Additionally, the tanker unloading station was equipped with an earthing control system with the possibility of blocking the technological process in the event that earthing failure is detected.
The performed works, which included technical calculations, supply, installation, commissioning as well as warranty and post-warranty service, helped the client to adapt the plant to the requirements of the ATEX Directive in the field of explosion safety.
Plant modifications must be followed by an update of the EPD
After the modernisation of the explosion protection of the silos, it became necessary to update the Explosion Protection Document, which will be carried out by our ATEX specialists. This must always be done after any modifications with a significant impact on the explosion safety have been made to the plant. The updated EPD shall take into account the new HRD explosion venting and decoupling system for each silo. In this way, the client will have a complete document required from the employers in accordance with the applicable law.
