Supercritical water oxidation with hydrothermal flame as internal heat source: Efficient and clean energy production from waste

Queiroz, Joao Paulo Silva; Bermejo, M. Dolores; Mato, Fidel; Cocero, Marı́a José

doi:10.1016/j.supflu.2014.09.018

Cited by 71 publications

(23 citation statements)

References 97 publications

(166 reference statements)

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“…Even though the most immediate application of hydrothermal flames is in the SCWO process for waste destruction, which is the most industrially developed hydrothermal process, it is possible to move from the idea of hydrothermal flame as a technology for the destruction of wastes to consider it as a technology for the generation of clean energy, which could eventually substitute the actual technologies based on atmospheric combustion [16]. Supercritical water is already applied in energy fields through gasification processes for waste valorization Facchinetti et al [17], R€ onnlund et al [18].…”

Section: Introductionmentioning

confidence: 99%

Supercritical water oxidation for energy production by hydrothermal flame as internal heat source. Experimental results and energetic study

Cabeza

Queiroz

Criado

et al. 2015

Energy

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This work presents experimental and model results from a new configuration of a cooled wall reactor working with two outlets: an upper outlet through which a salt-free hot effluent (500 -600 • C) is obtained and a lower outlet through which an effluent at subcritical temperature dissolving the precipitated salts is obtained. Different flow distributions were tested in order to find the best elimination conditions. Total organic carbon removal over 99.99% was obtained at injection temperatures as low as room temperature, when the fraction of products leaving the reactor in the upper effluent is lower than 70% of the feed flow. The performance of the reactor was tested with the oxidation of a recalcitrant compound such as ammonia, using isopropyl alcohol as co-fuel.Removals higher than 99% of N-NH + 4 were achieved in both effluents, working with temperatures near 700 • C. Slightly better eliminations were obtained in the bottom effluent because its residence time in the reactor is longer. The behavior of the reactor working with feeds with a high concentration of salts was also tested. Feeds containing up to 2.5% wt Na 2 SO 4 could be injected * Corresponding author. Phone: +34 983423166Email addresses: palabreras@gmail.com (Pablo Cabeza), joao.deq@gmail.com (Joao Paulo Silva Queiroz), mcriado_sastre@hotmail.com (Manuel Criado), crisbaterna@gmail.com (Cristina Jimenez), mdbermejo@iq.uva.es (Maria Dolores Bermejo), fidel@iq.uva.es (Fidel Mato), mjcocero@iq.uva.es (Maria Jose Cocero) 1 Present address: Dept. of Chemical Engineering -Universidade Federal de PernambucoProf. Artur de Sá, s/n, -Cidade Universitária -50740-521, Recife, PE -Brazil Preprint submitted to Energy March 2, 2015 in the reactor without plugging problems and a total organic carbon removal of 99.7% was achieved in these conditions. Upper effluent always presented a concentration of salt lower than 30 ppm. Finally, a theoretical analysis of the energy recovery of the reactor working with two outlets was made.

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Section: Introductionmentioning

confidence: 99%

Supercritical water oxidation for energy production by hydrothermal flame as internal heat source. Experimental results and energetic study

Cabeza

Queiroz

Criado

et al. 2015

Energy

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“…[16][17][18][19] Alternative processes have been suggested involving electrochemical, photochemical, electrophotochemical, and thermal approaches,a sw ell as using supercritical conditions. [20][21][22][23] Previous studies on the reactivity of amavadin with H 2 O 2 did not identify the source of gas generation. [7] Thus,a n oxidant without activated oxygen or metal-oxo species,a sis the case of Ce 4+ ,c ould provide au seful tool to identify the origin of the dioxygen evolution and was used in this study, which shows that very similar amavadin models act as mediators of water oxidation under mild conditions without requiring light assistance.…”

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confidence: 99%

Amavadin and Homologues as Mediators of Water Oxidation

et al. 2015

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The vanadium(IV) N-hydroxyiminodicarboxylate complexes [V(HIDPA)2](2-) and [V(HIDA)2](2-), close models of the amavadin (a natural product from Amanita fungi lacking the V=O group but exhibiting a rare NO-bound oxyiminate moiety), are shown to be the first recognized complexes of the early transition metals (up to periodic Group 7) that mediate the oxidation of water. The reactions were analyzed by visible spectrophotometry, mass spectrometry, and measurement of evolved dioxygen using Ce(4+) as sacrificial oxidant. A mechanism proposed on the basis of DFT calculations involves the reversible oxidation to the mononuclear V(V)-{OṄ<} center, where the redox active oxyimino group plays a key role and metal oxidation state variation is only one unit. The more similar model of the metallobiomolecule, [V(HIDPA)2](2-), displays a lower oxidation rate than [V(HIDA)2](2-) but does not undergo appreciable degradation, in contrast to the latter.

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“…The combustion products of a hydrothermal flame release enough energy to heat the low temperature feedstock to the desired reaction temperature, so reducing the risk of salt deposition in the preheating exchanger. This type of reactor not only improves the reliability of the SCWO system, but also reduces its operation cost [72,[96][97][98]. But more significantly, salt deposition is mainly concentrated to occur in the reactor, which can be overcome by reactor configuration.…”

Section: Particular Reactor Designsmentioning

confidence: 99%