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Conflict of Interest: In relation to this article, we declare that there is no conflict of interest.

Publication history: Received August 8, 2005
Accepted December 11, 2005

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Effect of NaOH on the decomposition of halogenated hydrocarbon by supercritical water oxidation

Sang-Ha Son Jong-Hwa Kim¹ Hyeon-Chul Lee² Chang-Ha Lee^†

Department of Chemical Engineering, Yonsei University, Seoul 120-749, Korea ¹New Energy and Environment System Research Institute, Yonsei University, Seoul 120-749, Korea ²Manufacturing Engineering R&D Institute, Samsung Electro Mechanics. Co., LTD., Suwon 443-743, Korea

Korean Journal of Chemical Engineering, May 2006, 23(3), 385-390(6), 10.1007/BF02706739

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Abstract

To protect alloys from corrosion phenomena in the supercritical water oxidation (SCWO) process, the effects of neutralizer on the conversion and corrosion were investigated. The surface morphologies of all the alloy coupons exposed to 2,4-Dichlorophenol (2,4-DCP) in the SCWO were significantly changed in microscopic images. The theoretical amount of NaOH as a neutralizer was calculated under the assumption of complete oxidation of 2,4-DCP. The pre-dosed NaOH in the range of 100% to 300% stoichiometric amount could not affect significantly the pH value in the SCWO. Moreover, the pH=7 was not achieved until 700% stoichiometric amount of NaOH was pre-dosed to the reactor. It is noted that the conversion rate recorded over 99% without oxidant when 800% of NaOH was pre-dosed into the reactor. In addition, under the addition of H2O2 as an oxidant, the increased amount of NaOH led to the improvement of conversion rate. The pre-dosed NaOH may contribute to the conversion rate of 2,4-DCP in the SCWO. However, due to low solubility of salt in the SCWO, the fouling problem should be solved in the SCWO process.

Keywords

Supercritical Water Oxidation Corrosion Neutralizer Alloy 2,4-DCP

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