Removing VOCs during the production of bitumen roofing

We installed a small filter, the AIRCON 200, on an airstream of 100 m3/h. The total flow rate from the production hall is 20 000 to 40 000 m3/h, so if the pilot proved successful, we would need to scale up by a factor of 200 to 400.

We employed a two-step process to measure the outcome. Firstly, by a simple smell test of the treated air at the outlet. Secondly, by using a flame ionisation detector (FID) already installed by the client.

As expected, we found that the fresh activated carbon in our filters adsorbed all the compounds at the beginning of the pilot project. As the filter beds became more saturated, we began to detect low concentrations of hydrocarbonsin the treated flow.

From this, we could ascertain how long each filter would last; and analyse the spent carbon to see how much pollution it was adsorbing. We calculated that our large standard filter, the AIRCON V-XL, would be appropriate as a long-term solution.

However, the client wanted to be certain there would be no breakthrough, so we decided to place a second filter in series as back-up. This also means that the first filter can be fully exhausted before it is exchanged, lowering carbon consumption and operating costs.

During the development of the project, the client decided to include a further emissions stream in the set-up. The final design, therefore, was for two AIRCON V-XL filters in series.

This factory varies its production level to meet demand, increasing hours in the spring and summer, reducing them in the autumn, and shutting down completely for a period in the winter. Activated carbon is ideal for discontinuous production, as it can be simply put on hold with no standby costs until production restarts.