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Armando T. Quitain

Bio: Armando T. Quitain is an academic researcher from Kumamoto University. The author has contributed to research in topics: Catalysis & Supercritical fluid. The author has an hindex of 28, co-authored 121 publications receiving 2406 citations. Previous affiliations of Armando T. Quitain include Nagoya University & Toyohashi University of Technology.


Papers
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TL;DR: In this article, the decomposition behavior of five selected amino acids in high-temperature and high-pressure water was studied using a continuous-flow tubular reactor, and the effect of temperature on reaction products, pathway, and rate was determined as a function of reaction time.
Abstract: Decomposition behavior of five selected amino acids in high-temperature and high-pressure water was studied using a continuous-flow tubular reactor. The reaction was carried out in the temperature range of 200−340 °C at a pressure of 20 MPa. Alanine and its derivatives leucine, phenylalanine, serine, and aspartic acid were used as model amino acids. The effect of temperature on reaction products, pathway, and rate was determined as a function of reaction time. Alanine decomposed into lactic acid and pyruvic acid, then finally mineralized to carbon dioxide with an activation energy of 154 [kJ/mol] at 20 MPa. The degradation rate decreased in the following order: aspartic acid, serine, phenylalanine, leucine, and alanine. The general reaction network of amino acids under hydrothermal conditions takes two main paths: deamination to produce ammonia and organic acids, and decarboxylation to produce carbonic acid and amines. Deamination was the predominant reaction in the decomposition of aspartic acid, an ac...

290 citations

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TL;DR: Production of low-molecular-weight carboxylic acids from the hydrothermal treatment of representative organic wastes and compounds with or without oxidant demonstrated that the presence of oxidants favored formation of organic acids with acetic acid being the major product.

137 citations

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TL;DR: In this article, the effect of temperature, pressure and reaction time on the subcritical and supercritical hydrothermal liquefaction of oil palm empty fruit bunch, palm mesocarp fiber and palm kernel shell was investigated using a Inconel batch reactor.

108 citations

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TL;DR: In this paper, the liquefaction of three types of oil palm biomass; empty fruit bunch (EFB), palm mesocarp fiber (PMF) and palm kernel shell (PKS) using water at subcritical and supercritical conditions was investigated.
Abstract: This paper presents the studies on the liquefaction of three types of oil palm biomass; empty fruit bunch (EFB), palm mesocarp fiber (PMF) and palm kernel shell (PKS) using water at subcritical and supercritical conditions. The effect of temperature (330, 360, 390 °C) and pressure (25, 30, 35 MPa) on bio-oil yields were investigated in the liquefaction process using a Inconel batch reactor. The optimum liquefaction condition of the three types of biomass was found to be at supercritical condition of water i.e. at 390 °C and 25 MPa, with PKS yielding the maximum bio-oil yield of 38.53 wt%, followed by EFB and PMF, with optimum yields of 37.39 wt% and 34.32 wt%, respectively. The chemical compositions of the bio-oils produced at optimum condition were analyzed using GC–MS and phenolic compounds constituted the major portion of the bio-oils, with other minor compounds present such as alcohols, ketones, aromatic hydrocarbons and esters.

101 citations

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TL;DR: The possibility of amino acids and glucosamine production from the treatment of shrimp shells in high-temperature and high-pressure water was investigated in this paper, where the highest amount of amino acid (70 mg/g of dry shrimp shell) from hydrolysis of proteins was obtained at a reaction temperature of 523 K in 60 min.
Abstract: The possibility of amino acids and glucosamine production from the treatment of shrimp shells in high-temperature and high-pressure water was investigated. Under the tested conditions, the highest amount of amino acids (70 mg/g of dry shrimp shell) from hydrolysis of proteins was obtained at a reaction temperature of 523 K in 60 min. This amount was about 2.5 times the total amino acids obtained at 363 K, the temperature at which shrimp extracts for use in noodles soup are being prepared. The amount of simple amino acids such as glycine and alanine increased with increasing temperature up to 523 K and decreased thereafter. This behavior has also been observed from other seafood processing wastes such as fish entrails and scallop wastes. Glucosamine was not detected presumably because of its deamination to produce glucose or cellulose. To further investigate the reason for the nonformation of glucosamine from shrimp shells, experiments on chitin as the starting reaction material were carried out.

101 citations


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TL;DR: Several biomass hydrothermal conversion processes are in development or demonstration as mentioned in this paper, which are generally lower temperature (200-400 °C) reactions which produce liquid products, often called bio-oil or bio-crude.
Abstract: Hydrothermal technologies are broadly defined as chemical and physical transformations in high-temperature (200–600 °C), high-pressure (5–40 MPa) liquid or supercritical water. This thermochemical means of reforming biomass may have energetic advantages, since, when water is heated at high pressures a phase change to steam is avoided which avoids large enthalpic energy penalties. Biological chemicals undergo a range of reactions, including dehydration and decarboxylation reactions, which are influenced by the temperature, pressure, concentration, and presence of homogeneous or heterogeneous catalysts. Several biomass hydrothermal conversion processes are in development or demonstration. Liquefaction processes are generally lower temperature (200–400 °C) reactions which produce liquid products, often called “bio-oil” or “bio-crude”. Gasification processes generally take place at higher temperatures (400–700 °C) and can produce methane or hydrogen gases in high yields.

1,822 citations

Journal ArticleDOI
01 May 2011-Energy
TL;DR: In this paper, the authors present a review of the current status of the hydrothermal liquefaction of biomass with the aim of describing the current state of the technology, which is a medium-temperature, high-pressure thermochemical process which produces a liquid product, often called bio-oil or bi-crude.

1,451 citations

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TL;DR: Supercritical extraction and fractionation of natural matter is one of the early and most studied applications in the field of supercritical fluids in the last 10 years, studies on the extraction of classical compounds like essential and seed oils from various sources, with or without the addition of a co-solvent have been published.
Abstract: Supercritical extraction and fractionation of natural matter is one of the early and most studied applications in the field of supercritical fluids In the last 10 years, studies on the extraction of classical compounds like essential and seed oils from various sources: seeds, fruits, leaves, flowers, rhizomes, etc, with or without the addition of a co-solvent have been published Supercritical extraction of antioxidants, pharmaceuticals, colouring matters, and pesticides has also been studied The separation of liquid mixtures and the antisolvent extraction are other processes that can perform very interesting separations Mathematical modelling has also been developed and refined for some of these processes The objective of this review is to critically analyze traditional and new directions in the research on natural matter separation by supercritical fluids extraction and fractionation

1,003 citations

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TL;DR: Broad agreement is reached between predictive yields and actual yields for the microalgae based on their biochemical composition, and the yields of bio-crude follow the trend lipids>proteins>carbohydrates.

973 citations

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TL;DR: In this paper, researches on biochar are discussed in terms of production method and application, and different processes for biochar production, such as pyrolysis, gasification, hydrothermal carbonization, etc.

809 citations