Activated carbon gives benzene no chance
The removal of different substances is quite rightly an absolute priority in the European Community as a matter of public health. Besides the already stringent European standard, the Netherlands recently went a step further to limit the emission of benzene to an absolute minimum. Activated carbon filtration as the last step of a purification line helps companies to easily comply with the considerably more stringent standards for benzene.
Benzene is a substance found in mineral oil and is mainly produced from petroleum. It is very commonly found at refineries in the petrochemical industry, tank terminals for the storage and transfer of crude oil, petroleum, naphtha, and so on. Also used in numerous other applications, the pure substance benzene is among the most widely produced chemical substances. It is also an important chemical base component for many other substances.
The use of benzene is increasingly being curtailed. The European Union already has strict standards for benzene emissions. In Belgium, the maximum concentration amounts to 1 ppm. The same standard was also in force in the Netherlands up to 1 October 2017. In the meantime, based on current knowledge the GR (Health Council) in the Netherlands has again assessed the effects of benzene and has been able to derive a threshold value. The legal limit value for benzene has therefore been decreased from 3.25 mg/m3 (1 ppm) to 0.7 mg/m3 (0.2 ppm) at a time-weighted average of 8 hours (TWA8).
In view of the strong presence of the petrochemical industry in Belgium, among other countries, it is quite possible that Belgium will adopt this strict standard in the long term. At European level, too, a tightening of the standard is certainly in place over time. Most European countries currently maintain a level of 1 ppm. Some countries, such as Denmark, Sweden and Finland, have already introduced a reduced limit of 0.5 ppm.
Full control of benzene emissions is perfectly possible by the addition of activated carbon filtration as the last step in an air purification process. During the last ‘polish’ phase you can, for example, opt for two activated carbon filtration in series. With this redundant system, the first activated carbon filter ensures the elimination of the very last benzene concentrations. When the first filter is saturated, the second filter immediately takes over.
Desotec obviously ensures correct sizing depending on the project. This quickly integrative approach has numerous advantages. The consumption of activated carbon remains very limited, considering the filter works as the last step in the purification line and the benzene concentrations have already been considerably reduced. The system also barely requires any maintenance. Investing in such a solution certainly pays off in the long term, because there will be an even more stringent approach to emissions of these substances in the future.
At DESOTEC’s facilities, all used carbon is analysed so the right measures can be taken for handling and removing the saturated carbon out of the mobile filters. All molecules that were adsorbed on the activated carbon at the customers’ site, are desorbed inside DESOTEC’s reactivation furnaces. These contaminants are then fully destroyed, in accordance with National and European legislation, by an incineration and neutralisation setup. The entire installation and it's emissions are under continuous on-line monitoring, which guarantees that only harmless water vapour is seen exiting the chimney.