| Popis: |
The removal of organic pollutants from ship emission was studied using two processes namely electron beam (EB) and hybrid EB with wet scrubbing process. A mobile accelerator unit was used to treat 4915 Nm3/h of flue gas emitted from a tugboat in Riga Shipyard. A volume of 3 m3 seawater containing 36.8 mM of NaClO2 oxidant was used as a wet scrubber solution. Organic pollutants, mainly volatile organic pollutants (VOCs), were collected at three different sampling points, before and after irradiation vessels, and after wet-scrubber unit, respectively. They were collected with glass sampling bottles, tedlar bags, Coconut Shell Charcoal (CSC) sorbents and XAD-2 sorbents. CH3OH and CH3OH/CH2Cl2 (1:1) were used to extract VOCs from CSC and XAD-2 sorbents, respectively. Syringe filters were used to obtain the solid-free extraction solutions. They were concentrated using a micro-extractor under continuously blowing high-purity Ar. A gas chromatography–mass spectrometry (GC-MS) was used for analysis. The identified organic compounds were: aliphatic hydrocarbons (dodecane C12H26 to eicosane C20H42), aromatic hydrocarbon (toluene), esters (C3H7COOCH3, (C4H9OCO)2C6H4), nitro compounds (C3H5NO3, C4H7NO2) and acid (C7H15COOH). After 4.2 kGy EB irradiation, around 50–100% aliphatic hydrocarbons, 83% toluene and 7.5% (C4H9OCO)2C6H4 were removed from the off-gases, and after EB hybrid wet-scrubber process, most organic compounds including nitro compounds were removed. Only trace amount of toluene, hexadecane, octadecane and dibutyl phthalate were found to be present in the gas phase. |
