Characterization of Vinasse for Thermochemical Conversion - Fuel Fractionation, Release of Inorganics, and Ash-Melting Behavior

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Abstract

Thedistribution of ash-forming elements in dried vinasse was characterized bysequentially leaching it in H2O, NH4Ac, and HCl. In addition, the release of inorganics duringcombustion and CO2 gasification of the vinasse at 900 °C in a singleparticle reactor was determined. Furthermore, the vinasse was ashed at 500 °C,and the melting behavior of the ash as a function of temperature was firstpredicted using FactSage thermodynamic calculations and then validated usingdifferential scanning calorimetry (DSC)−thermogravimetric analysis (TGA)measurements. The fuel fractionation results revealed that almost all of theash-forming elements, except Si, Al, and Fe, in the vinasse were completelywater-soluble. Moreover, unlike other solid fuels, significant portions of Si,Al, and Fe in the vinasse were water-soluble, owing to its origin, juice fromwater-extracted cane stalks, and acidic nature. Analysis results of the ashesfrom the combustion and gasification experiments showed that none of the water-and acetate-soluble Si, Al, Fe, and P in the vinasse was released duringcombustion and gasification. However, significant levels of the water- andacetate-soluble K, Na, Ca, Mg, S, and Cl were released during the vinassethermal conversion in both gas conditions, with the release levels being higherin CO2 than in O2. The thermodynamic calculation and DSC−TGA measurementresults showed that the initial melting temperature of the vinasse ash was640−645 °C, and the temperatures corresponding to 15 and 70% melt fractionswere 650 and 670−690 °C, respectively. The low-temperature melting ash and therelease of significant amounts of water- and acetate-soluble alkali and alkalichlorides during thermal conversion suggest that vinasse is a challenging fuelfor combustion and gasification in conventional boilers and gasifiers.

Original languageUndefined/Unknown
Pages (from-to)5840–5848
JournalEnergy and Fuels
Volume33
Issue number7
DOIs
Publication statusPublished - 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • Ash-melting behavior
  • Ash-forming elements
  • Thermochemical conversion
  • Vinasse
  • Fuel fractionation

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