Co-oxidation in supercritical water : methylphosphonic acid-ethanol and ammonia-ethanol model systems

Supercritical water (SCW) is an effective solvent for the destruction of organic compounds by oxidation. Because both organics and oxygen have high solubility in water above its critical point (To = 374 °C (647 K), Pc = 221 bar), they can be reacted together in a single phase which avoids mass transfer limitations. At typical operating conditions (T= 450 to 650 °C, P = 240 to 300 bar) for supercritical water oxidation (SCWO), H-C-N compounds are rapidly and completely oxidized to water, carbon dioxide, nitrogen, and nitrous oxide. The destruction of organic compounds in SCWO takes place primarily through free radical pathways rather than the ionic pathways that dominate in liquid water. This is because SCW acts as a nonpolar solvent with a dielectric constant ranging from 1.2 at T= 650 °C and P = 250 bar to 2.5 at T= 450 °C and P = 250 bar as compared to ambient water which has a dielectric constant equal to 80. The ion product of water, K, similarly drops to between 10-8 and 102° over this temperature range as compared to the ambient value of 10-14. Typically, SCWO has been studied by the analysis of either the oxidation of single model compounds to determine detailed kinetic mechanisms or by the oxidation of complex simulated waste streams to measure DRE levels.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Ploeger, Jason M

Advisor dc:contributor.advisor

• Jefferson W. Tester.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/35518
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/35518

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/35518