http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kinetic Analysis for Decomposition of 2,4-Dichlorophenol by Supercritical Water Oxidation
이창하,황경엽,이현철,Jung-Hyun In,Jong-Hwa Kim 한국화학공학회 2005 Korean Journal of Chemical Engineering Vol.22 No.6
2,4-Dichlorophenol (2,4-DCP), as a halogenated model pollutant, was decomposed by using supercritical water oxidation (SCWO) in a batch reactor made of Hastelloy C-276. SCWO experiments for 2,4-DCP decomposition were performed in the range of 380-420 oC, 230-280 bar and 0.074- 0.221 mol/L H2O2. The effect of oxidant concentration on decomposition rate and efficiency was significant near the critical temperature of 380 oC. However, the role of the oxidant concentration in the SCWO process decreased with an increase in temperature; also, excess oxidant played a key role in quite significantly decreasing the activation energy of 2,4-DCP oxidation. Variation of the reaction rate by the change of pressure was negligible even at a near critical temperature. The kinetic rate for the decomposition of 2,4-DCP in the SCWO process was well described by a simple first-order kinetic and global reaction rate model. From the SCWO experiments, the various intermediates identified with a GC/MS implied that the first reaction pathway for 2,4-DCP decomposition led to dimers such as dichlorophenoxyphenols, and the second led to single-ring and ringopening products.
Corrosion Behavior of 316L Stainless Steel in Supercritical Water
Yoon, SJ.H.,Kim, H.S.,Kim, Y.S.,Mitton, B.,Latanision, R.M. 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-
We were investigated intending to obtain the fundamental data for developing the corrosion resistant steel for the construction of SCWO (supercritical water oxidation) system. In order to match these objects, the effects of various factors on the corrosion resistance of flat specimen, welded specimen and U-bend specimen of 316L stainless steel in trimsol solution A trimsol solution of cutting oil produces a lot of Cl elements during the decomposition under supercritical condition. By the result, the corroded product of surface was composed of the composite and multi-layers that oxides or salts is mixed, and dealloying phenomena was observed in the nearest surface of 316L alloy. Main corrosion mechanism under SCWO condition is the intergranular corrosion and pitting corrosion and erosion. Initial corrosion of welded specimen that has the dendrite structure is generally progressed through the crevice of dendrite. Especially, in microstructure of the outer surface part in the U-bend specimen that maximum tensile stress is applied, some cracks with the intergranular and the intragranular corrosion with SCC were observed in the deep inside from the surface of the specimen. On the other hand, in inner side that compression stress is applied, the intergranular corrosion was only observed. The expected factors, dominating corrosion resistance of 316L alloy in supercritical water oxidation environments, are the amount of alloying elements and grain size and hardness that means resistance against erosion.
Pentachlorophenol oxidation rates in supercritical water
Han, Seung Ho,Veriansyah, Bambang,Kim, Jae-Duck,Lee, Jong-Chol Taylor & Francis Inc. 2007 Journal of Environmental Science and Health. Part Vol.42 No.14
<P> The oxidation rate of pentachlorophenol, [C6HCl5O] which is used to control termites and as a general herbicide and also as the probable human's carcinogen, was investigated in an isothermal continuous tubular reactor under supercritical water oxidation (SCWO) conditions. The experiments were conducted at a temperature of 400-550°C and a fixed pressure of 25 MPa, with a residence time that ranged from 6 s to 26 s. The conversion of PCP was monitored by analyzing total organic carbon (TOC) on the liquid effluent samples. The initial TOC concentrations of PCP were varied from 0.74 mmol/L to 2.91 mmol/L and the oxygen concentrations were varied from 0.46 mmol/L to 3.52 mmol/L. By taking into account the dependence of the oxidant and TOC concentration on the reaction rate, a global PCP oxidation rate was regressed from the data of 48 experiments, to a 95% confidence level. The resulting activation energy was determined to be 43.56 ± 1.47 kJ/mol, and the pre-exponential factor was (1.92 ± 0.46) × 102 L1.16 mmol-0.16 s-1. The reaction orders for the PCP (based on TOC) and the oxidant were 0.74 ± 0.02 and 0.42 ± 0.05, respectively.</P>