REMOVAL OF BUTYLACETATE AND XYLENE FROM AIR BY ELECTRON-BEAM - A PRODUCT STUDY

VOC emissions from industrial processes can cause hazardous impacts on the environment through increased ozone and smog formation. Previously, it was demonstrated that the electron beam technology is a powerful tool to scrub small amounts of VOC from large volume flows at ambient temperature. In this paper, product analyses are presented for the removal of common aliphatic and aromatic hydrocarbons from air. Butylacetate and xylene were added to an air stream of 1000 Nm(3)/h at concentration levels close to 100 mg C/Nm(3), and irradiated with 550 keV electrons at the AGATE-2 pilot plant of KfK. The removal efficiencies were measured by FID and GC in the dose range 0 - 10 kGy. The removal efficiency of xylene was found to be close to 90% at 10 kGy which is almost twice as high as that of butylacetate. Three types of products were measured quantitatively by wet chemical analysis, filtration, and FTIR: (i) organic acids (formic, acetic, propionic, butyric acid) (ii) aerosol (iii) inorganic products and by-products (CO, CO2, O-3, NOx) The major product obtained from xylene irradiation was a particulate matter with a molecular C/O ratio close to 1.5. No aerosol formation was observed in case of butylacetate, the major irradiation product of which was acetic acid. Less than 15% of the removed carbon were converted to CO and CO2 in both cases. The total carbon balance was 95 +/- 15% in all experiments. By model calculation with the AGATE-code, the removal efficiencies and product distributions can be interpreted starting from OH radical attack on the hydrocarbon molecules and subsequent mechanisms which are known from atmospheric chemistry.