Salt precipitation and scale control in supercritical water oxidation—Part A: fundamentals and research

Hodes, Marc; Marrone, Philip A.; Hong, Glenn T.; Smith, Kenneth A.; Tester, Jefferson W.

doi:10.1016/s0896-8446(03)00093-7

Cited by 199 publications

(123 citation statements)

References 42 publications

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“…1 One such advantage is the potential for extraction and recovery of naturally occurring inorganic components, e.g., Ca, K, Mg, Na, P, S, N, from liquefied biomass stock during processing. As the solubility of dissolved inorganics decreases under hydrothermal conditions, 2 salts bearing the essential nutrients N, P, and K are precipitated and can be removed in a salt-separation step. This facilitates the recovery of inorganic material that can be recycled for use as fertilizer.…”

Section: Introductionmentioning

confidence: 99%

X-ray Absorption Fine Structure Study of the Effect of Protonation on Disorder and Multiple Scattering in Phosphate Solutions and Solids

et al. 2009

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Phosphorus K-edge X-ray absorption fine structure (XAFS) was explored as a means to distinguish between aqueous and solid phosphates and to detect changes in phosphate protonation state. Data were collected for H 3 PO 4 , KH 2 PO 4 , K 2 HPO 4 and K 3 PO 4 solids and solutions and for the more complex phosphates, hydroxylapatite (HAP) and struvite (MAP). The X-ray absorption near-edge structure (XANES) spectra for solid samples are distinguishable from those of solutions by a shoulder at ∼4.5 eV above the edge, caused by scattering from cation sites. For phosphate species, the intensity of the white line peak increased for solid and decreased for aqueous samples, respectively, with phosphate deprotonation. This was assigned to increasing charge delocalization in solid samples, and the effect of solvating water molecules on charge for aqueous samples. In the extended X-ray absorption fine structure (EXAFS), backscattering from first-shell O atoms dominated the (k) spectra. Multiple scattering (MS) via a four-legged P-O 1 -P-O 1 -P collinear path was localized in the lower k region at ∼3.5 Å -1 and contributed significantly to the beat pattern of the first oscillation. For EXAFS analysis, increasing Debye-Waller factors suggest more disorder in the P-O shell with addition of protons to the crystal structure due to the lengthening effects of P-OH bonds. This disorder produces splitting in the hybridized P 3p-O 2p band in the density of states. For aqueous samples, however, increased protonation reduced the structural disorder within this shell. This was linked to a change from kosmotropic to chaotropic behavior of the phosphate species, with reduced effects of H bonding on structural distortion. The intensity of MS is correlated to the degree of disorder in the P-O shell, with more ordered structures exhibiting enhanced MS. The observed trends in the XAFS data can be used to distinguish between phosphate species in both solid and aqueous samples. This is applicable to many chemical, geochemical and biological systems, and may be an important tool for determining the behavior of phosphate during the hydrothermal gasification of biomass.

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Section: Introductionmentioning

confidence: 99%

X-ray Absorption Fine Structure Study of the Effect of Protonation on Disorder and Multiple Scattering in Phosphate Solutions and Solids

et al. 2009

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“…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%

“…Corrosion has historically impeded SCW commercialization due to limited reactor life (Barner et al, 1992;Hodes et al, 2004). Metal corrosion in SCW systems is driven, in part, by water's own natural solvation characteristics and is largely localized to areas where water drops below the critical point (Marrone & Hong, 2009).…”

Section: Corrosion Influence On Reactor Designmentioning

confidence: 99%

“…Waste-dissolved salts can precipitate and, if not controlled, eventually block SCW reactors (Brunner, 2009a(Brunner, , 2009bDemirbas, 2011a;Marrone et al, 2004). Salt precipitation persistently complicates SCW systems (Du et al, 2010), thereby impeding widespread commercialization due to inherent practical difficulties of scale buildup, fouling, and corrosion (Cocero et al, 2003;Hodes et al, 2004). Salt handling represents one of the greatest remaining technical challenges for development of SCW biomass gasification processes at commercial scales .…”

Section: Salt Precipitation and Scaling Influence On Reactor Designmentioning

confidence: 99%

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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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“…Wet oxidation has shown its effectiveness and promising property with several industrial effluents, including benzene, biphenyls, amines and pyridine [8][9][10][11] .This process performed the liquid-phase oxidation of toxic or poorly biodegradable compounds under high temperature (150~350 °C) and pressure (2.0~15.0 MPa) conditions, using a gaseous source of oxygen or air. During this process, the pollutants were oxidized completely [12,13] . It should be noted that, this process can be considered as a green and environmental-friendly technology since it emits no harmful materials or secondary pollution to the environment [14,15] .…”

Section: Introductionmentioning

confidence: 99%

Wet hydrogen peroxide oxidation of synthetic pharmaceutical wastewater as a pretreatment method

Zeng¹,

Li²,

Zhao³

2016

Proceedings of the 2015 4th International Conference on Sensors, Measurement and Intelligent Materials

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Keywords: Wet hydrogen peroxide oxidation; Synthetic pharmaceutical wastewater; Pretreatment method. Abstract. Wet hydrogen peroxide oxidation of synthetic pharmaceutical wastewater as a pretreatment method was investigated. The reaction parameters, such as reaction temperature and time, pH and the additional amount of H 2 O 2 , were examined using a batch reactor with COD removal rate as a standard for assessing. Results showed that the highest removal rate of COD was obtained at 240 ºC for 60 min with the H 2 O 2 additional amount 2 mL. HPLC analysis results showed that the pollutants in synthetic pharmaceutical wastewater were converted into small molecule carboxylic acids after the reaction, therefore the biodegradability of wastewater was enhanced. Wet hydrogen peroxide oxidation treatment displayed effectively for the pretreatment of synthetic pharmaceutical wastewater.

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Salt precipitation and scale control in supercritical water oxidation—Part A: fundamentals and research

Cited by 199 publications

References 42 publications

X-ray Absorption Fine Structure Study of the Effect of Protonation on Disorder and Multiple Scattering in Phosphate Solutions and Solids

X-ray Absorption Fine Structure Study of the Effect of Protonation on Disorder and Multiple Scattering in Phosphate Solutions and Solids

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

Wet hydrogen peroxide oxidation of synthetic pharmaceutical wastewater as a pretreatment method

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