Supercritical water oxidation: A technical review

Bermejo, M. Dolores; Cocero, Marı́a José

doi:10.1002/aic.10993

Cited by 367 publications

(192 citation statements)

References 120 publications

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“…High-performance ceramics (e.g., Al2O3, ZrO2, SiO2, Si3N4, Ce2O3, and TiO2) have been used as supports for catalysts in SCW (Azadi et al, 2011;Ding et al, 1996;Lee, 2011). All of these ceramics are, however, subject to thermal creep at much lower temperatures than when exposed to hightemperature gases, thereby allowing the supported catalyst particles to contact each other, then sinter, weld, or polish, rendering them inactive (Bermejo & Cocero, 2006b;Hyde et al, 2001). Ceramic supports also serve as nucleation points for salts, which can quickly plug reactors and deactivate the catalysts (Aki & Abraham, 1999;Brunner, 2009a).…”

Section: Catalytically Augmented Supercritical Watermentioning

confidence: 99%

“…The objective of SCWO, however, is to oxidatively destroy organic compounds in water (Bermejo & Cocero, 2006b;Jing et al, 2008). The technology was originally developed nearly 30 years ago at the Massachusetts Institute of Technology for NASA, back when it was thought there would be a human colony on the moon and a need for a single system to treat and purify water was a priority (Bubenheim & Wydeven, 1994;Modell, 1977;Modell et al, 1982;Slavin & Oleson, 1991;Sloan et al, 2008;Svanström et al, 2004;Svanström et al, 2005).…”

Section: Supercritical Water Oxidation (Scwo)mentioning

confidence: 99%

“…The characterization of inherently arbitrary reactor feed equilibria, however, is complicated by thermodynamic mechanics of fluid mechanics, heat transfer, mass transfer, kinetics, and phase behavior . Modeling, predicting, and defining these thermodynamic mechanisms is difficult, and there is no straightforward explanation in the literature for SCW reaction kinetic mechanisms (Azadi & Farnood, 2011;Bermejo & Cocero, 2006b;Bernardi et al, 2010;Hodes et al, 2004;Lu et al, 2010). The assumed, basic reaction kinetics are represented by the formulas (3-8) listed below (Chun et al, 2011;White et al, 2011):…”

Section: Reactor Kinetics and Design Considerationsmentioning

confidence: 99%

“…Even when water's transport properties can be predicted, thermodynamic phase equilibria are still handicapped by varying real-world, compositions of reactant educts and the presence of inorganic salts (Bermejo & Cocero, 2006b). Furthermore, the sequential and simultaneous progression of hydrolysis, pyrolysis, steam-reforming, and water-gas shift reactions in supercritical gasification chemistry are complex and have yet to be comprehensively described beyond speculative assumptions based largely on limited observations and first-order kinetics (Calzavara et al, 2005;Kruse, 2009;Matsumura et al, 2005;Sato et al, 2004;Vogel et al, 2005).…”

Section: Reactor Kinetics and Design Considerationsmentioning

confidence: 99%

See 3 more Smart Citations

Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

Kamler¹,

Soria²

2012

Gasification for Practical Applications

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Section: Catalytically Augmented Supercritical Watermentioning

confidence: 99%

Section: Supercritical Water Oxidation (Scwo)mentioning

confidence: 99%

Section: Reactor Kinetics and Design Considerationsmentioning

confidence: 99%

Section: Reactor Kinetics and Design Considerationsmentioning

confidence: 99%

See 2 more Smart Citations

Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

Kamler¹,

Soria²

2012

Gasification for Practical Applications

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“…This process occurs in four main steps: (1) raising the pressure of the oxidizing agents, (2) the reaction, (3) separating the salt, and (4) depressurization and heat recovery. [22] While this method is expected to efficiently destroy acetic acid, the required high temperature and pressure conditions seem too extreme for a unit operation processing radioactive materials as part of the UREX+ process.…”

Section: Destructionmentioning

confidence: 99%

Development of Acetic Acid Removal Technology for the UREX+Process

Counce¹,

Watson²

2009

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OVERALL ABSTRACTIt is imperative that acetic acid is removed from a waste stream in the UREX+ process so that nitric acid can be recycled and possible interference with downstream steps can be avoided.Acetic acid arises from acetohydroxamic acid (AHA), and is used to suppress plutonium in the first step of the UREX+ process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for the removal of acetic acid.The tributyl phosphate (TBP)-dodecane diluent, used in both UREX and NPEX, was determined to be a solvent system that gave sufficient distribution coefficients for acetic acid in addition to a high separation factor from nitric acid. This solvent system was tested under various TBP concentrations in the dodecane to provide information that can be used for further flow sheet development. The role of water in the acetic acid removal step was quantified in this study and is reported here. The performance of the annual centrifugal contactor for this acetic acid removal step was also quantified and reported here.Each step in the UREX+ process was examined to determine if there was any acetic acid interference in the performance of any step of the UREX+ flow sheet that would make it necessary to remove the acetic acid prior to that step. It was found that no interference with acetic acid was present. Therefore, the acetic acid removal step can be placed essentially anywhere in the process. For simplicity, it has been proposed to place the removal step at the end of the process after TALSPEAK where all desirable metals have already been extracted and the nitric acid waste stream is prepared to be recycled. This project is funded by the Advanced Fuel Cycle Initiative (AFCI) as part of the Nuclear Energy Research Initiative (NERI) and the Global Nuclear Energy Partnership (GNEP). The goals of these programs are to establish a fuel reprocessing system capable of recovering fissile materials from spent nuclear fuel for reuse in nuclear power reactors, inhibit the purification of plutonium through co-extraction with actinides, and create an alternative process for recycle of spent nuclear fuel rather than co-extraction in the current once throughplutonium and uranium extraction (PUREX) method. The production of energy from uranium at an increased industrial level would create a substantial decrease in coal and petroleum dependence for our energy sources. The inhibition of plutonium purification makes it more difficult for plutonium to be used in non-peaceful uses. The recycle of the spent fuel components also creates much less waste for deposition into such repositories as Yucca Mountain. LIST OF TABLES LIST OF FIGURESOne process utilizing these objectives is the Uranium Extraction (UREX+) process. The first step in this flow sheet is the Uranium Extraction (UREX) ste...

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Supercritical Fluids

Martín

Cocero

2016

Kirk-Othmer Encyclopedia of Chemical Technology

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A supercritical fluid is a gas that is pressurized and heated to a compressed fluid state, which is above both the critical pressure and the temperature. In this state, density and subsequently solvent strength and transport properties are highly adjustable by modest changes in temperature and pressure. Complex phase behavior and interactions with materials occurring in this state can be examined experimentally and described by molecular thermodynamics. Carbon dioxide and water are two substances used frequently as supercritical fluids. Carbon dioxide, which may be used independently or in the presence of various cosolvents, is used because of its environmentally benign nature and low cost. Water is used because of its efficiency in destroying hazardous aqueous pollutants and hydrothermal synthesis.Numerous supercritical fluid processes have been commercialized, including coffee and tea decaffeination, supercritical water oxidation, and supercritical fluid chromatography. Process research and development involving supercritical fluids are progressing in many diverse areas, including extraction, membrane filtration, polymerization, particle formation, cleaning and drying, and applications in microelectronic engineering.

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Supercritical water oxidation: A technical review

Cited by 367 publications

References 120 publications

Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

Development of Acetic Acid Removal Technology for the UREX+Process

Supercritical Fluids

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