Co-oxidation of methylphosphonic acid and ethanol in supercritical water I: Experimental results

Ploeger, Jason M.; Bielenberg, Patricia A.; Lachance, Russell P.; Tester, Jefferson W.

doi:10.1016/j.supflu.2006.03.002

Cited by 17 publications

(12 citation statements)

References 15 publications

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“…Figure 4 compares the ammonia conversion data for three experiments at T = 700°C and P = 246 bar: [NH 3 ] o = 1 mM and [O 2 ] o = 0.75 mM (Φ = 1), [NH 3 ] o = 1 mM and [O 2 ] o = 1.05 mM, (Φ = 0.73), and [NH 3 ] o = [EtOH] o = 1 mM, [O 2 ] o = 1.05 mM (Φ = 1). The cooxidation enhancement of ethanol is approximately the same (∼10%) as the enhancement gained when oxygen is added, which is consistent with what was seen for low concentrations of ethanol added to methylphosphonic acid (MPA) 25…”

Section: Resultssupporting

confidence: 84%

Cooxidation of ammonia and ethanol in supercritical water, part 1: Experimental results

2007

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in Wiley InterScience (www.interscience.wiley.com).The cooxidative effect of ethanol on ammonia oxidation in supercritical water was studied for a range of temperatures (655-7058C), initial ammonia (1-3 mM), ethanol (0-1.0 mM), and oxygen concentrations (0.7-5.0 mM), corresponding to fuel equivalence ratios ranging from 0.9 to 2.2 for the complete combustion of both organic species. With a stoichiometric amount of oxygen available for complete oxidation, the addition of ethanol on an equivalent molar basis was found to increase ammonia conversion from 20 to 65% at initial concentrations of 1 mM for each reactant, T ¼ 7008C, P ¼ 246 bar, and t ¼ 2.5 s. Nitrous oxide was produced in much larger quantities for ammonia-ethanol cooxidation than for ammonia oxidation. Based on fractional yields of nitrogen product, this amounted to 40-75% for co-oxidation with ethanol versus 4-13% without ethanol present.

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Section: Resultssupporting

confidence: 84%

Cooxidation of ammonia and ethanol in supercritical water, part 1: Experimental results

2007

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“…SCWO mechanisms and rates were initially based on known gas-phase oxidation chemistry, with adjustments and additions made to replicate observed product yields under SCWO conditions. Increasingly complex chemical kinetic models ultimately led to a kinetic model for SCWO of ethanol, based on a modified Marinov mechanism. ,, As validated experimentally, ,, the mechanisms and rates for oxidation chemistry of ethanol in supercritical water are analogous to the gas-phase oxidation of ethanol in combustion systems. Thus, insights into the dominant mechanisms and pathways for oxidation of ethanol in SCW can be gained by studying the combustion literature.…”

Section: Introductionmentioning

confidence: 99%

“…Supercritical water oxidation (SCWO) has been demonstrated for the destruction of complex organic and inorganic compounds, with destruction and removal efficiencies (DRE) in excess of 99.99% and low char yields for optimized process parameters. , Applications have been limited due to the high capital costs of SCWO systems, which can mostly be attributed to the specialty alloys and elegant designs needed to mitigate known issues with material corrosion and salt precipitation. − Extensive previous work has been done to characterize the oxidation kinetics, pathways, and mechanisms for simple model compounds in supercritical water, including ethanol. Early model compound studies were performed at MIT, ,− Sandia National Laboratories, − and a few other places. ,− A brief summary of relevant SCWO studies is provided here.…”

Section: Introductionmentioning

confidence: 99%

Partial Oxidation of Ethanol in Supercritical Water

Pinkard

Purohit

Moore

et al. 2020

Ind. Eng. Chem. Res.

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Ethanol is partially oxidized in a continuous supercritical water reactor at temperatures from 500 to 530 °C, constant pressure of 25 MPa, initial ethanol concentration of 5 wt %, residence times of 3−8 s, and oxidant-to-fuel stoichiometric equivalence ratios of 5, 7.5, and 10%. The experimental conditions are selected to study the regime where ethanol oxidation happens rapidly but below the temperature necessary to initiate hydrolysis reactions. The reactions and interactions of intermediate species can be analyzed, leveraging previous experimental results and the existing body of literature on ethanol hydrolysis, pyrolysis, and oxidation. Higher oxidant concentration increases ethanol destruction and gasification efficiency, although significant coke/char buildup is qualitatively observed within the reactor. Product yields from the experiments are used to infer significant reaction mechanisms, and a pathway is postulated for the counterintuitive formation of char under the studied conditions.

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“…The co‐oxidation effect which served as an outstanding rate enhancer in SCW has drawn much attention in recent years, whereby the oxidation of the labile component could accelerate the decomposition of the recalcitrant component in supercritical water . By means of the co‐oxidation approach, which can enhance the destruction of the refractory pollutant prominently, the operation condition of the SCWO can be reduced, improving the corresponding corrosion and economic problems to a great extent.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the fact that SCW with a low dielectric constant is highly aprotic and nonpolar, it is the free radical reaction that occurred during the SCWO of the organic compounds and not the ionic pathway. Accordingly, the free radical reaction was the dominant process during the SCWO . The detailed chemical kinetics model takes elementary reaction mechanisms and kinetics as its foundation.…”

Section: Introductionmentioning

confidence: 99%

Experimental and kinetics study on oxidation of three‐component in supercritical water

et al. 2019

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The supercritical water oxidation of a methanol, acetic acid, and phenol mixture was investigated in this study. The experimental design was accomplished by means of response surface methodology. 16 experimental runs were performed in a continuous tubular reactor. Quadratic polynomial equations with a satisfactory data fit and accuracy were established on the basis of the experimental results. The calculation results demonstrate the promotion behaviour of methanol, the inhibition behaviour of acetic acid, and the positive effect of phenol on the supercritical water oxidation of the ternary mixture. The interactive effect of the mechanism was characterized by means of the computational simulation with the mechanism‐based kinetic model. It seems that the positive influence of methanol was derived from the co‐oxidation effect of the methanol in the destruction of both acetic acid and phenol. The oxidation of acetic acid was restrained in the mixture system, which is attributed to the more favourable radical capture for phenol, and, thus, the overall disappearance kinetics was retarded with the addition of acetic acid. Finally, the co‐oxidation enhancement of both methanol and acetic acid related to phenol oxidation in supercritical water contributed to the positive effect of phenol on mixture oxidation efficiencies.

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Co-oxidation of methylphosphonic acid and ethanol in supercritical water I: Experimental results

Cited by 17 publications

References 15 publications

Cooxidation of ammonia and ethanol in supercritical water, part 1: Experimental results

Cooxidation of ammonia and ethanol in supercritical water, part 1: Experimental results

Partial Oxidation of Ethanol in Supercritical Water

Experimental and kinetics study on oxidation of three‐component in supercritical water

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