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.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
References
Connolly, J. F., “Solubility of hydrocarbons in water near the critical temperature,”J. Chem. Eng. Data,11, 13 (1966).
Dell’Orco, P. C., Gloyna, E. F. and Buelow, S. J., “Reactions of Nitrate Salts with ammonia in supercritical water,”Ind. Eng. Chem. Res.,36, 2547 (1997).
DiNaro, J. L., Tester, J. W. and Howard, J. B., “Experimental measurements of benzene oxidation in supercritical water,”AIChE J.,46, 2274 (2000).
Goto, M., Nada, T., Ogata, A., Kodama, A. and Hirose, T., “Supercritical water oxidation for the destruction of municipal excess sludge and alcohol distillery wastewater of molasses,”J. Supercrit. Fluids,13, 277 (1998).
Hatakeda, K., Ikushima, Y., Sato, O., Aizawa, T. and Saito, N., “Supercritical water oxidation of polychlorinated biphenyls using hydrogen peroxide,”Chem. Eng. Sci.,54, 3079 (1999).
Kang, K. Y. and Chun, B. S., “Behavior of hydrothermal decomposition of silk fibroin to amino acids in near-critical water,”Korean J. Chem. Eng.,21, 654 (2004).
Konys, J., Fodi, S., Hausselt, J., Schmidt, H. and Casal, V., “Corrosion of high-temperature alloys in chloride-containing supercritical water oxidation systems,”Corrosion,55, 45 (1999).
Kriksunov, L. B. and Macdonald, D., “Corrosion in supercritical water oxidation systems: a phenomenological analysis,”J. Electrochem. Soc.,142, 4069 (1995).
Kritzer, P., Boukis, N. and Dinjus, E., “Corrosion of alloy 625 in aqueous solutions containing chloride and oxygen,”Corrosion,54, 824 (1998).
Kritzer, P., Boukis, N. and Dinjus, E., “Factors controlling corrosion in high-temperature aqueous solutions: a contribution to the dissociation and solubility data influencing corrosion processes,”J. Supercrit. Fluids,15, 205 (1999).
Lee, G., Nunoura, T., Matsumura, Y. and Yamamoto, K., “Comparison of the effects of the addition of NaOH on the decomposition of 2-chlorophenol and phenol in supercritical water and under supercritical water oxidation conditions,”J. Supercrit. Fluids,24, 239 (2002).
Lee, G., Nunoura, T., Matsumura, Y. and Yamamoto, K., “Effects of a sodium hydroxide addition on the decomposition of 2-chlorophenol in supercritical water,”Ind. Eng. Chem. Res.,41, 5427 (2002).
Lee, H. C., In, J. H., Kim, J. H. and Lee, C. H., “Optimal condition for decomposition of ethylenediaminetetraacetic acid (EDTA) in supercritical water oxidation,”Korean Chem. Eng. Res.,43, 318 (2005).
Lee, H. C., In, J. H., Lee, S. Y., Kim, J. H. and Lee, C. H., “An anti-corrosive reactor for the decomposition of halogenated hydrocarbons with supercritical water oxidation,”J. Supercrit. Fluids,36, 59 (2005).
Lee, H. C., Son, S. H., Hwang, K. Y. and Lee, C. H., “Surface chemical analysis on corrosion of alloys in supercritical water oxidation of halogenated hydrocarbon,”Ind. Eng. Chem. Res.,45, 3412 (2006).
Martino, C. J. and Savage, P. E., “Thermal decomposition of substituted phenols in supercritical water,”Ind. Eng. Chem. Res.,36, 1385 (1997).
Modell, M.,Final Draft for Chapter 8–11, Standard Hand-book for Hazardous Wastes Treatment and Disposal, H. M. Freeman. ed. (1986).
Peter, K. and Eckhard, D., “An assessment of supercritical water oxidation (SCWO): Existing problems, possible solutions and new reactor concepts,”Chem. Eng. J.,83, 207 (2001).
Zhou, N., Krishnan, A., Vogel, F. and Peters, W. A., “A computational model for supercritical water oxidation of organic toxic wastes,”Advances in Environmental Research,4, 79 (2000).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Son, SH., Kim, JH., Lee, HC. et al. Effect of NaOH on the decomposition of halogenated hydrocarbon by supercritical water oxidation. Korean J. Chem. Eng. 23, 385–390 (2006). https://doi.org/10.1007/BF02706739
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02706739