The decomposition reactions and pathways of polychlorinated biphenyls(PCBs) in transformer oil were investigated under the supercritical water oxidation. Experiments were carried out in a continuous flow system at a constant temperature of 500℃, using ...

The decomposition reactions and pathways of polychlorinated biphenyls(PCBs) in transformer oil were investigated under the supercritical water oxidation. Experiments were carried out in a continuous flow system at a constant temperature of 500℃, using hydrogen peroxide as oxidant in excess, and different pressure ranging from 24 to 29 MPa. The obtained results are summarized as follows ;
1. The analytical methods for the various organic compounds expected to be formed from the degradation of PCBs during supercritical water oxidation were considered to guarantee the analytical quality in this study.
2. A specially designed experiments were carried out in the absence and presence of methanol to understand the effect of oil contents on the supercritical water oxidation of PCBs in transformer oil. In the absence of methanol, PCBs were destructed after most of oils(98.5% of reduced oils and 37.2 seconds of residence time) were reduced and destruction rates(82.3%) of PCBs were finally achieved at the residence time of 54.9 seconds.
On the other hand, in the presence of methanol, the conversions of PCBs were increased by 2 times over that of PCBs in the absence of methanol and PCBs were destructed completely at the residence time of 52.3 seconds.
3. The initial step of PCBs degradation was evaluated. The congener specific analysis indicates that the dechlorination of PCBs into lower chlorinated biphenyls is feasible, which also undergo oxidation decomposition. The identified reaction products are biphenyl, lower chlorinated PCB congeners, chlorophenols, chlorobenzenes, lower PCDDs and PCDF, etc.
4. Chlorophenol, chlorobenzenes, dibenzofurans, and dibenzo-p-dioxin were identified as reaction products from oxidation of PCBs in transformer oil under the condition of supercritical water. These products are known as a reaction products from the phenol incineration. This observation suggests that there may be a relationship between the two thermal oxidation processes(SCWO and incineration).

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절연유 중 함유되어 있는 폴리염화비페닐을 초임계수 산화 방법에 의해 분해한 결과에 대하여 해석한 논문으로서 논문의 이론적 배경에 대한 고찰 및 문헌 조사가 적절히 수행되었으며 실제 실험을 통하여 얻어진 데이터에 대한 해석 방법 또한 적절한 것으로 판단되어집니다.
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